U.S. patent application number 15/307561 was filed with the patent office on 2017-02-23 for device.
This patent application is currently assigned to SONY CORPORATION. The applicant listed for this patent is SONY CORPORATION. Invention is credited to Sho FURUICHI, Hiroaki TAKANO, Hiromasa UCHIYAMA.
Application Number | 20170055202 15/307561 |
Document ID | / |
Family ID | 54392350 |
Filed Date | 2017-02-23 |
United States Patent
Application |
20170055202 |
Kind Code |
A1 |
UCHIYAMA; Hiromasa ; et
al. |
February 23, 2017 |
DEVICE
Abstract
A device including a measurement unit configured to perform
measurement of each of one or more frequency bands that are a part
of a plurality of frequency bands that are not used by a terminal
device. The measurement unit does not perform measurement of each
of the remaining frequency bands among the plurality of frequency
bands or performs measurement of each of the remaining frequency
bands at a frequency lower than a frequency of the measurements of
each of the one or more frequency bands, which makes it possible to
improve measurement performed by a terminal device.
Inventors: |
UCHIYAMA; Hiromasa; (Tokyo,
JP) ; TAKANO; Hiroaki; (Saitama, JP) ;
FURUICHI; Sho; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SONY CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
SONY CORPORATION
Tokyo
JP
|
Family ID: |
54392350 |
Appl. No.: |
15/307561 |
Filed: |
February 17, 2015 |
PCT Filed: |
February 17, 2015 |
PCT NO: |
PCT/JP2015/054271 |
371 Date: |
October 28, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 52/0209 20130101;
H04L 5/0048 20130101; Y02D 70/164 20180101; Y02D 70/142 20180101;
Y02D 70/1262 20180101; Y02D 70/21 20180101; Y02D 30/70 20200801;
Y02D 70/1264 20180101; H04W 88/02 20130101; H04W 24/10 20130101;
H04W 72/0453 20130101; Y02D 70/166 20180101; H04W 72/04 20130101;
H04W 48/16 20130101 |
International
Class: |
H04W 48/16 20060101
H04W048/16; H04W 72/04 20060101 H04W072/04; H04L 5/00 20060101
H04L005/00; H04W 52/02 20060101 H04W052/02 |
Foreign Application Data
Date |
Code |
Application Number |
May 9, 2014 |
JP |
2014-097822 |
Claims
1-16. (canceled)
17. A device comprising: a measurement unit configured to perform
measurement of a first frequency band based on a discovery
reference signal transmitted in the first frequency band within a
first period included in a measurement gap and perform measurement
of a second frequency band based on a reference signal transmitted
in the second frequency band within a second period included in the
measurement gap.
18. The device according to claim 17, wherein the measurement gap
is an extended measurement gap.
19-21. (canceled)
22. The device according to claim 17, wherein the reference signal
transmitted in the second frequency band is a discovery reference
signal.
23. (canceled)
24. The device according to claim 17, wherein the measurement unit
performs the measurement of the first frequency band that is used
by the same base station based on a discovery reference signal and
a cell-specific reference signal transmitted by the same base
station in the first frequency band within the first period or
performs the measurement of the second frequency band that is used
by the same base station based on a discovery reference signal and
a cell-specific reference signal transmitted by the same base
station in the second frequency band within the second period.
25. The device according to claim 24, wherein at least one of the
first period and the second period is a period shorter than 6
milliseconds.
26. The device according to claim 17, wherein the measurement unit
performs measurement of a frequency group and measurement of one or
more other frequency bands or measurement of one or more other
frequency groups based on a priority of the frequency group
including the first frequency band and the second frequency band
and a priority of the one or more other frequency bands or a
priority of the one or more other frequency groups.
27-28. (canceled)
29. The device according to claim 17, wherein the measurement gap
includes an additional period, and the measurement unit performs
measurement of an additional frequency band based on a discovery
reference signal transmitted in the additional frequency band
within the additional period.
30. A device comprising: an acquiring unit configured to acquire
information indicating a first frequency band in which a discovery
reference signal is transmitted within at least a first period
included in a measurement gap; and a control unit configured to
notify a terminal device of the first frequency band and the
measurement gap.
31. The device according to claim 30, wherein the measurement gap
further includes a second period in which a reference signal is
transmitted in a second frequency band.
32. The device according to claim 30, wherein the measurement gap
is an extended measurement gap.
33. (canceled)
34. The device according to claim 30, wherein the acquiring unit
acquires information indicating a frequency group including the
first frequency band and a second frequency band, and the control
unit notifies a terminal device of the frequency group and the
measurement gap.
35-36. (canceled)
37. A device comprising: an acquiring unit configured to acquire
information about a first frequency band in which a discovery
reference signal is transmitted; and a control unit configured to
decide an extended measurement gap including at least a part of a
transmission period in which a discovery reference signal is
transmitted in the first frequency band.
38. The device according to claim 37, wherein the control unit
controls the transmission period such that at least a part of the
transmission period is included in the extended measurement
gap.
39. The device according to claim 37, wherein the information about
the first frequency band includes information indicating the
transmission period, and the control unit decides the extended
measurement gap based on the transmission period.
40. A device comprising: an acquiring unit configured to acquire
information about two or more frequency bands in which a discovery
reference signal is transmitted; and a control unit configured to
decide a frequency group including at least a first frequency band
and a second frequency band among the two or more frequency bands,
wherein the first frequency band is a frequency band in which a
discovery reference signal is transmitted within at least a first
period included in a measurement gap, and the second frequency band
is a frequency band in which a discovery reference signal is
transmitted within at least a second period included in the
measurement gap.
41. The device according to claim 40, wherein the control unit
controls a transmission period in which a discovery reference
signal is transmitted in the first frequency band such that the
discovery reference signal is transmitted in the first frequency
band within at least the first period, or controls a transmission
period in which a discovery reference signal is transmitted in the
second frequency band such that the discovery reference signal is
transmitted in the second frequency band within at least the second
period.
42. The device according to claim 40, wherein the information about
the two or more frequency bands includes information indicating a
transmission period in which a discovery reference signal is
transmitted in each of the two or more frequency bands, and the
control unit decides the frequency group based on the transmission
period.
43. A device comprising: a measurement unit configured to perform
first measurement of each of a plurality of frequency bands and
perform second measurement of each of one or more frequency bands
that are a part of the plurality of frequency bands, wherein the
first measurement is measurement that is performed based on a
reference signal transmitted within a period having a first length,
and the second measurement is measurement that is performed based
on a reference signal transmitted within a period having a second
length that is greater than the first length.
44. The device according to claim 43, wherein the one or more
frequency bands are frequency bands that are selected from among
the plurality of frequency bands based on a result of the first
measurement.
45. (canceled)
46. The device according to claim 43, wherein the device is a
terminal device or a module for the terminal device, and each of
the plurality of frequency bands is a frequency band that is not
used by the terminal device.
47-50. (canceled)
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a device.
BACKGROUND ART
[0002] In cellular systems according to communication standards
such as Long Term Evolution (LTE), a terminal device performs
measurement based on a reference signal for cell selection/cell
reselection and a handover. For example, measurement of a frequency
band that the terminal device does not use is referred to as
inter-frequency measurement and is performed in a measurement
gap.
[0003] Various technologies for measurement performed by a terminal
device are proposed. For example, Patent Literature 1 discloses a
technology in which a measurement gap is assigned to more component
carriers as channel quality decreases.
CITATION LIST
Patent Literature
[0004] Patent Literature 1 JP 2014-53971A
SUMMARY OF INVENTION
Technical Problem
[0005] However, when more frequency bands (for example, component
carriers) are assigned to a system, for example, more measurements
are necessary. For example, more inter-frequency measurements are
necessary. In this case, for example, a terminal device performs
inter-frequency measurement at a higher frequency. As a result,
power consumption of the terminal device increases and system
throughput may decrease or inter-frequency measurement may consume
much time.
[0006] Therefore, it is preferable to provide a mechanism through
which measurement performed by a terminal device can be
improved.
Solution to Problem
[0007] According to the present disclosure, there is provided a
device including: a measurement unit configured to perform
measurement of each of one or more frequency bands that are a part
of a plurality of frequency bands that are not used by a terminal
device. The measurement unit does not perform measurement of each
of remaining frequency bands among the plurality of frequency bands
or performs the measurement of each of the remaining frequency
bands at a frequency lower than a frequency of the measurements of
each of the one or more frequency bands.
[0008] According to the present disclosure, there is provided a
device including: an acquiring unit configured to acquire
information about a plurality of frequency bands that are not used
by a terminal device; and a control unit configured to instruct the
terminal device to perform measurement of each of one or more
frequency bands that are a part of the plurality of frequency
bands, and not to perform measurement of each of remaining
frequency bands among the plurality of frequency bands or to
perform the measurement of each of the remaining frequency bands at
a frequency lower than a frequency of the measurements of each of
the one or more frequency bands.
[0009] According to the present disclosure, there is provided a
device including: a measurement unit configured to perform
measurement of a first frequency band based on a discovery
reference signal transmitted in the first frequency band within a
first period included in a measurement gap and perform measurement
of a second frequency band based on a reference signal transmitted
in the second frequency band within a second period included in the
measurement gap.
[0010] According to the present disclosure, there is provided a
device including: an acquiring unit configured to acquire
information indicating a first frequency band in which a discovery
reference signal is transmitted within at least a first period
included in a measurement gap; and a control unit configured to
notify a terminal device of the first frequency band and the
measurement gap.
[0011] According to the present disclosure, there is provided a
device including: an acquiring unit configured to acquire
information about a first frequency band in which a discovery
reference signal is transmitted; and a control unit configured to
decide an extended measurement gap including at least a part of a
transmission period in which a discovery reference signal is
transmitted in the first frequency band.
[0012] According to the present disclosure, there is provided a
device including: an acquiring unit configured to acquire
information about two or more frequency bands in which a discovery
reference signal is transmitted, and a control unit configured to
decide a frequency group including at least a first frequency band
and a second frequency band among the two or more frequency bands.
The first frequency band is a frequency band in which a discovery
reference signal is transmitted within at least a first period
included in a measurement gap, and the second frequency band is a
frequency band in which a discovery reference signal is transmitted
within at least a second period included in the measurement
gap.
[0013] According to the present disclosure, there is provided a
device including: a measurement unit configured to perform first
measurement of each of a plurality of frequency bands and perform
second measurement of each of one or more frequency bands that are
a part of the plurality of frequency bands. The first measurement
is measurement that is performed based on a reference signal
transmitted within a period having a first length, and the second
measurement is measurement that is performed based on a reference
signal transmitted within a period having a second length that is
greater than the first length.
Advantageous Effects of Invention
[0014] As described above, according to the present disclosure, it
is possible to improve measurement performed by a terminal device.
Note that the effects described above are not necessarily
limitative. With or in the place of the above effects, there may be
achieved any one of the effects described in this specification or
other effects that may be grasped from this specification.
BRIEF DESCRIPTION OF DRAWINGS
[0015] FIG. 1 is an explanatory diagram for describing an example
of a small cell.
[0016] FIG. 2 is an explanatory diagram for describing an example
of a small cell cluster.
[0017] FIG. 3 is a sequence diagram illustrating an example of a
schematic flow of an on/off process of a small cell.
[0018] FIG. 4 is a sequence diagram illustrating an example of a
schematic flow of an on/off process of a small cell when a DRS is
used.
[0019] FIG. 5 is an explanatory diagram for describing an example
of a measurement gap.
[0020] FIG. 6 is an explanatory diagram for describing a first
scenario of carrier aggregation (CA).
[0021] FIG. 7 is an explanatory diagram for describing a second
scenario of carrier aggregation (CA)
[0022] FIG. 8 is an explanatory diagram for describing a third
scenario of carrier aggregation (CA).
[0023] FIG. 9 is a first explanatory diagram for describing an
example of measurement in a small cell on/off environment.
[0024] FIG. 10 is a second explanatory diagram for describing an
example of measurement in a small cell on/off environment.
[0025] FIG. 11 is an explanatory diagram illustrating an example of
a schematic configuration of a communication system according to an
embodiment of the present disclosure.
[0026] FIG. 12 is a block diagram illustrating an example of a
configuration of a terminal device according to a first
embodiment.
[0027] FIG. 13 is an explanatory diagram for describing a first
example of measurement according to the first embodiment.
[0028] FIG. 14 is an explanatory diagram for describing a second
example of measurement according to the first embodiment.
[0029] FIG. 15 is an explanatory diagram for describing a third
example of measurement according to the first embodiment.
[0030] FIG. 16 is a block diagram illustrating an example of a
configuration of a base station according to the first
embodiment.
[0031] FIG. 17 is a sequence diagram illustrating a first example
of a schematic flow of a process according to the first
embodiment.
[0032] FIG. 18 is a sequence diagram illustrating a second example
of a schematic flow of a process according to the first
embodiment.
[0033] FIG. 19 is an explanatory diagram for describing a first
example of measurement according to a modification example of the
first embodiment.
[0034] FIG. 20 is an explanatory diagram for describing a second
example of measurement according to a modification example of the
first embodiment.
[0035] FIG. 21 is an explanatory diagram for describing a third
example of measurement according to a modification example of the
first embodiment.
[0036] FIG. 22 is a block diagram illustrating an example of a
configuration of a terminal device according to a second
embodiment
[0037] FIG. 23 is an explanatory diagram for describing a first
example of measurement according to the second embodiment.
[0038] FIG. 24 is an explanatory diagram for describing a second
example of measurement according to the second embodiment.
[0039] FIG. 25 is an explanatory diagram for describing a third
example of measurement according to the second embodiment.
[0040] FIG. 26 is a block diagram illustrating an example of a
configuration of a base station according to the second
embodiment.
[0041] FIG. 27 is a block diagram illustrating an example of a
configuration of a control entity according to the second
embodiment
[0042] FIG. 28 is a sequence diagram illustrating an example of a
schematic flow of a process according to the second embodiment.
[0043] FIG. 29 is a sequence diagram illustrating a first example
of a schematic flow of a frequency group decision process according
to the second embodiment.
[0044] FIG. 30 is a sequence diagram illustrating a second example
of a schematic flow of a frequency group decision process according
to the second embodiment.
[0045] FIG. 31 is a block diagram illustrating an example of a
configuration of a terminal device according to a third
embodiment
[0046] FIG. 32 is an explanatory diagram for describing a first
example of measurement according to the third embodiment.
[0047] FIG. 33 is an explanatory diagram for describing a second
example of measurement according to the third embodiment.
[0048] FIG. 34 is an explanatory diagram for describing a third
example of measurement according to the third embodiment.
[0049] FIG. 35 is an explanatory diagram for describing a fourth
example of measurement according to the third embodiment.
[0050] FIG. 36 is a block diagram illustrating an example of a
configuration of a base station according to the third
embodiment.
[0051] FIG. 37 is a block diagram illustrating an example of a
configuration of a control entity according to the third
embodiment.
[0052] FIG. 38 is a sequence diagram illustrating an example of a
schematic flow of a process according to the third embodiment.
[0053] FIG. 39 is a sequence diagram illustrating a first example
of a schematic flow of an extended measurement gap decision process
according to the third embodiment.
[0054] FIG. 40 is a sequence diagram illustrating a second example
of a schematic flow of an extended measurement gap decision process
according to the third embodiment.
[0055] FIG. 41 is a block diagram illustrating an example of a
configuration of a terminal device according to the second
embodiment.
[0056] FIG. 42 is an explanatory diagram for describing an example
of frequency bands that are targets of first measurement and second
measurement according to a fourth embodiment.
[0057] FIG. 43 is a flowchart illustrating an example of a
schematic flow of a process according to the fourth embodiment
[0058] FIG. 44 is a block diagram illustrating an example of a
schematic configuration of a server.
[0059] FIG. 45 is a block diagram illustrating a first example of a
schematic configuration of an eNB
[0060] FIG. 46 is a block diagram illustrating a second example of
the schematic configuration of the eNB.
[0061] FIG. 47 is a block diagram illustrating an example of a
schematic configuration of a smartphone.
[0062] FIG. 48 is a block diagram illustrating an example of a
schematic configuration of a car navigation apparatus.
DESCRIPTION OF EMBODIMENT(S)
[0063] Hereinafter, (a) preferred embodiment(s) of the present
disclosure will be described in detail with reference to the
appended drawings. In this specification and the drawings, elements
that have substantially the same function and structure are denoted
with the same reference signs, and repeated explanation is
omitted
[0064] In this specification and the drawings, there are cases in
which components having substantially the same functional
configuration are distinguished by adding different alphabets to
the end of the same reference numeral. For example, a plurality of
components having substantially the same functional configuration
are distinguished like small base stations 15A, 15B, and 15C as
necessary. However, when a plurality of components having
substantially the same functional configuration need not be
particularly distinguished, only the same reference numeral is
added. For example, when the small base stations 15A, 15B, and 15C
need not be particularly distinguished, they are referred to simply
as a "small base stations 15."
[0065] The description will proceed in the following order.
1. Introduction
[0066] 1.1. Related technology 1.2. Problems related to measurement
2. Schematic configuration of communication system
3. First Embodiment
[0067] 3.1. Configuration of terminal device 3.2. Configuration of
base station 3.3. Process flow 3.4. Modification example
4. Second Embodiment
[0068] 4.1. Configuration of terminal device 4.2. Configuration of
base station 4.3. Configuration of control entity 4.4. Process flow
4.5. First modification example 4.6. Second modification
example
5. Third Embodiment
[0069] 5.1. Configuration of terminal device 5.2. Configuration of
base station 5.3. Configuration of control entity 5.4. Process flow
5.5. First modification example 5.6. Second modification
example
6. Third Embodiment
[0070] 6.1. Configuration of terminal device 6.2. Process flow 7.
Application examples 7.1. Application examples for control entity
7.2. Application examples for base station 7.3. Application
examples for terminal device
8. Conclusion
1. Introduction
[0071] First, a technology related to an embodiment of the present
disclosure and problems related to an embodiment of the present
disclosure will be described with reference to FIG. 1 to FIG.
10.
1.1. Related Technology
[0072] A technology related to an embodiment of the present
disclosure will be described with reference to FIG. 1 to FIG. 8.
Specifically, a small cell, a measurement and carrier aggregation
will be described.
(Small Cell)
(a) Small Cell
[0073] A small cell is a cell smaller than a macro cell. For
example, the small cell partially or entirely overlaps the macro
cell. Hereinafter, an example of the small cell will be described
with reference to FIG. 1.
[0074] FIG. 1 is an explanatory diagram for describing an example
of a small cell Referring to FIG. 1, a macro base station 11, a
macro cell 13, a small base station 15 and a small cell 17 are
shown. The macro base station 11 is a base station of the macro
cell 13. The small base station 15 is a base station of the small
cell 17. In other words, the macro cell 13 is a coverage area of
the macro base station 11 (that is, a communication area), and the
small cell 17 is a coverage area of the small base station 15 (that
is, a communication area).
[0075] A base station of LTE is referred to as an evolved node B
(eNB). Here, a macro base station of LTE is referred to as a macro
eNB, and a small base station of LTE is referred to as a small eNB.
In addition, a terminal device of LTE is referred to as user
equipment (UE).
(b) Small Cell Cluster
[0076] Small cells arranged at a high density form a small cell
cluster. Hereinafter, an example of the small cell cluster will be
described with reference to FIG. 2.
[0077] FIG. 2 is an explanatory diagram for describing an example
of a small cell cluster. Referring to FIG. 2, the macro base
station 11, the macro cell 13 and the small cell 17 are shown. For
example, small cells 17 arranged at a high density form a small
cell cluster 19.
(c) Small Cell on/Off
[0078] In a case in which small cells are arranged at a high
density, inter-cell interference causes a serious problem. In
general, the small base station transmits a cell-specific reference
signal (CRS) regardless of the presence or absence of traffic of
the small cell. In the case in which small cells are arranged at a
high density, it is known that a CRS causes large interference in a
neighbor cell. Therefore, various technologies for reducing
interference are being studied.
[0079] As a technology for reducing such inter-cell interference, a
small cell on/off technology has currently been focused on. In the
small cell on/off technology, an on/off state of a small cell is
adaptively switched, and thus it is possible to suppress
interference in a surrounding cell of the small cell. While a
trigger for switching an on/off state of the small cell has not yet
been specifically decided, a trigger for switching based on, for
example, a traffic amount, association of a terminal device, or
arrival of a packet is being studied. Hereinafter, an example of a
small cell on/off procedure will be described with reference to
FIG. 3.
[0080] FIG. 3 is a sequence diagram illustrating an example of a
schematic flow of a small cell on/off process. The small cell
on/off process is a process that is disclosed in R1-134318 of the
Third Generation Partnership Project (3GPP) When data to be
transmitted is generated, the UE transmits an uplink signal to a
macro eNB of a macro cell that is a serving cell (S1001). Then, the
macro eNB searches for a small eNB in an off state that is
positioned around the UE, and instructs the appropriate small eNB
to switch to an on state when there is an appropriate small eNB
(S1003). Then, the small eNB performs switching from the off state
to the on state (S1005). Then, the small eNB transmits downlink
signals such as a primary synchronization signal (PSS), a secondary
synchronization signal (SSS), a cell-specific reference signal
(CRS) and a physical broadcast channel (PBCH) signal (S1007). In
addition, the UE performs a cell search and RRM measurement
(S1009), and performs measurement reporting to the macro eNB
(S1011). Then, a handover of the UE from the macro cell to the
small cell is performed (S1013). Then, the UE and the small eNB
perform an access procedure (S1015) and perform data transmission
(S1017).
[0081] According to the procedure shown in FIG. 3, it is possible
to switch an on/off state of a small cell. However, according to
the procedure, a transition time may become relatively longer. That
is, according to the procedure, a time from when a terminal device
attempts to transmit data until the terminal device actually
transmits the data may become relatively longer. Therefore, large
improvement of throughput is difficult. In order to improve the
transition time, while the small cell is in the off state, a
measurement process that serves as a main delay factor is
preferably performed by the terminal device.
(d) Discovery Reference Signal
[0082] Introduction of a discovery reference signal (DRS) is being
studied in order to reduce the transition time. The DRS enables
measurement of a small cell in the off state. The DRS is also
referred to as a discovery signal (DS). A small base station (for
example, a small eNB) transmits a DRS while a small cell (or a
small base station) is in the off state, and a terminal device (for
example, UE) performs measurement based on a DRS. Hereinafter, an
example of a small cell on/off procedure when a DRS is used will be
described with reference to FIG. 4.
[0083] FIG. 4 is a sequence diagram illustrating an example of a
schematic flow of a small cell on/off process when a DRS is used.
The small cell on/off process is a process that is disclosed in
R1-134318 of the 3GPP. A macro eNB instructs a small eNB to
transmit a DS (S1031), and the small eNB transmits the DS in
downlink (S1033). The UE performs measurement based on the DS
(S1035) and reports a result of the measurement to the macro eNB
(that is, an eNB of a macro cell that is a serving cell) (S1037)
The UE and the small eNB perform data transmission through
subsequent procedures (S1041 to S1049) (S1051).
[0084] According to the procedure shown in FIG. 4, while the small
cell is in the off state, the terminal device can perform
measurement. Therefore, the transition time is removed and
throughput may be improved.
[0085] As various technologies for reducing interference,
enhancement on a transmission side and a reception side such as
muting, multiple instance and interference cancellation is also
being studied.
(Measurement)
(a) CRS Measurement
[0086] In LTE, a terminal device performs measurement based on a
CRS transmitted by a base station. Specifically, the terminal
device receives a CRS transmitted by a base station and thus
performs measurement of quality of a propagation path between the
base station and the terminal device. The measurement is referred
to as "radio resource management (RRM) measurement," or is simply
referred to as "measurement."
[0087] A result of the measurement is used to select a cell for a
terminal device. As a specific example, the result of the
measurement is used for cell selection/cell reselection by a
terminal device that is in a radio resource control (RRC) idle (RRC
Idle) state. In addition, for example, the result of the
measurement is reported to a base station by a terminal device that
is in an RRC connected state and is used for a handover decision by
the base station.
(b) RSRP and RSRQ
[0088] In LTE, CRS measurement is measurement of reference signal
received power (RSRP) and/or reference signal received quality
(RSRQ). In other words, a terminal device acquires RSRP and/or RSRQ
as a result of the measurement of the CRS. The RSRQ is calculated
from the RSRP and a received signal strength indicator (RSSI).
[0089] The RSRP is reception power of a CRS for each single
resource element. That is, the RSRP is an average value of
reception power of the CRS. The reception power of the CRS is
obtained by detecting a correlation between a reception signal in a
resource element of the CRS and a known signal CRS. The RSRP
corresponds to a desired signal "Signal (S)."
[0090] The RSSI is total power of signals for each Orthogonal
Frequency Division Multiple Access (OFDMA) symbol. Therefore, the
RSSI includes a desired signal, an interference signal and noise.
That is, the RSSI corresponds to "Signal (S)+Interference (I)+Noise
(N)."
[0091] The RSRQ is RSRP/(RSRI/N). N denotes the number of resource
blocks used for calculating an RSSI. The resource blocks are
resource blocks that are arranged in a frequency direction.
Therefore, the RSRQ is a value that is obtained by dividing the
RSRP using the RSRI for each resource block. That is, the RSRQ
corresponds to a signal-to-interference-plus-noise ratio
(SINR).
[0092] As described above, according to the measurement of the CRS,
reception power (that is, RSRP) and reception quality (that is,
RSRQ) such as an SINR are obtained.
(c) Measurement Timing
[0093] Measurement of a frequency band that a terminal device uses
is referred to as intra-frequency measurement. Conversely,
measurement of a frequency band that a terminal device does not use
is referred to as inter-frequency measurement
[0094] The terminal device can receive a CRS transmitted in a
frequency band that is used without switching a frequency of a
radio frequency (RF) circuit. That is, it is unnecessary to switch
a frequency of the RF circuit for intra-frequency measurement.
[0095] Conversely, in order for the terminal device to receive a
CRS transmitted in a frequency band that is not used, it is
necessary to switch a frequency of a radio frequency (RF) circuit.
That is, it is necessary to switch a frequency of the RF circuit
for inter-frequency measurement. Therefore, a period called a
measurement gap is used for inter-frequency measurement.
[0096] During the measurement gap, the base station does not
transmit a downlink signal addressed to a terminal device. In
addition, the measurement gap is shared between the base station
and the terminal device. For example, the base station transmits a
message (for example, an RRC connection reconfiguration message)
including information indicating a measurement gap to the terminal
device. For example, the measurement gap is indicated by a
measurement gap length (MGL), a measurement gap repetition period
(MGRP) and a gap offset. In addition, a combination of the MGL and
the MGRP is determined as, for example, a gap pattern. Hereinafter,
an example of the measurement gap will be described with reference
to FIG. 5
[0097] FIG. 5 is an explanatory diagram for describing an example
of a measurement gap. FIG. 5 shows a matrix including columns of
radio frames whose SFNs are 0 to 9 and rows of 10 subframes
(subframes whose subframe numbers are 0 to 9) included in radio
frames. In this example, the MGL is 6 milliseconds (ms), the MGRP
is 40 ms, and the gap offset is 0. Therefore, the measurement gap
has a length of 6 ms and appears every 40 ms. More specifically,
for example, six subframes whose subframe numbers are 0 to 5 among
radio frames whose SFNs are 0, 4 and 8 are the measurement gap.
Inter-frequency measurement is performed during the measurement
gap.
(d) Measurement Reporting
[0098] The terminal device reports a measurement result to the base
station. The reporting is referred to as measurement reporting.
[0099] The measurement reporting is periodic reporting or
event-triggered reporting. The periodic reporting is reporting that
is performed at set periods. Conversely, the event-triggered
reporting is reporting that is performed when a reporting event is
generated. Reporting events A1 to A5 are events associated with a
handover within a system, and reporting events B1 to B2 are events
associated with a handover between systems.
TABLE-US-00001 TABLE 1 Event Type Description Event A1 Serving
becomes better than threshold Event A2 Serving becomes worse than
threshold Event A3 Neighbour becomes offset better than serving
Event A4 Neighbour becomes better than threshold Event A5 Serving
becomes worse than threshold1 and neighbour becomes better than
threshold2 Event B1 Inter RAT neighbour becomes better than
threshold Event B2 Serving becomes worse than threshold1 and inter
RAT neighbour becomes better than threshold2
(Carrier Aggregation)
[0100] Carrier aggregation (CA) is a technology through which
communication is performed using a plurality of component carriers
(CCs) at the same time. The component carrier is a frequency band
having a maximum of a 20 MHz bandwidth. The carrier aggregation
includes three scenarios. Hereinafter, three scenarios of the
carrier aggregation will be described with reference to FIG. 6 to
FIG. 8.
[0101] FIG. 6 to FIG. 8 are explanatory diagrams for describing
first to third scenarios of carrier aggregation (CA). As
illustrated in FIG. 6, in the first scenario (intra-band
contiguous) of CA, the terminal device uses CCs adjacent in the
same operating. As illustrated in FIG. 7, in the second scenario
(intra-band non-contiguous) of CA, the terminal device uses CCs
that are not adjacent in the same operating. As illustrated in FIG.
8, in the third scenario (inter-band non-contiguous) of CA, the
terminal device uses CCs that are not adjacent in different
operating.
1.2. Problems Related to Measurement
[0102] (Problem Caused when Plurality of Frequency Bands are
Used)
[0103] When more frequency bands (for example, component carriers)
are assigned to a system, for example, more measurements are
necessary. For example, more inter-frequency measurements are
necessary. In this case, for example, the terminal device performs
inter-frequency measurement at a higher frequency. As a result,
power consumption of the terminal device increases and system
throughput may decrease or inter-frequency measurement may consume
much time.
[0104] Accordingly, in the embodiment of the present disclosure,
for example, it is possible to improve measurement performed by the
terminal device.
(Problem Caused in Small Cell on/Off Environment)
[0105] In addition, in current standards of 3GPP, inter-frequency
measurements are performed at periods of 40 ms or 80 ms. That is,
the inter-frequency measurement is frequently performed.
Conversely, in the current RAN2/RAN4, improvement of
inter-frequency measurement is being studied. For example, when a
measurement period increases, a measurement frequency decreases. As
a result, throughput and power consumption may be improved. The
measurement is referred to as relax measurement. However, when
relax measurement is introduced into an environment in which an
on/off state of a small cell is switched (hereinafter referred to
as a "small cell on/off environment"), for example, a discovery of
a small cell in the off state is delayed. This is because a base
station of a small cell (that is, a small base station) in the off
state periodically transmits a DRS.
[0106] Measurement in Current Cellular System
[0107] In a current cellular system, a terminal device generally
performs measurement based on a CRS transmitted in each subframe.
For example, the terminal device can perform intra-frequency
measurement based on a CRS transmitted in any subframe. In
addition, for example, the terminal device can perform
inter-frequency measurement based on a CRS transmitted in a
measurement gap.
[0108] Measurement in Small Cell on/Off Environment
[0109] As described above, transmission of a DRS in a small cell
on/off environment is being studied. A case in which a DRS is
transmitted for a relatively long period (for example, a period of
several tens to several hundreds of ms) in a small cell in the off
state is assumed. In addition, a case in which a DRS is transmitted
not only in a small cell in the off state but also in a small cell
in the on state is being studied. That is, in the small cell on/off
environment, only a DRS is transmitted in the small cell in the off
state and, conversely, a CRS and a DRS or only a CRS is transmitted
in the small cell in the on state.
[0110] The above-described measurements are summarized as
follows.
TABLE-US-00002 TABLE 2 Measurement Scenario Reference Signal
Transmission Period Period Existing CRS Always 40 ms or 80 ms Small
cell (on)DRS + CRS CRS: Always not yet On/Off or CRS only DRS: per
dozens/ determined (off)DRS hundreds of millisecond
Specific Example
[0111] Hereinafter, an example of measurement in a small cell
on/off environment will be described with reference to FIG. 9 and
FIG. 10.
[0112] FIG. 9 is a first explanatory diagram for describing an
example of measurement in a small cell on/off environment.
Referring to FIG. 9, the macro base station 11, the macro cell 13,
the small base station 15, the small cell 17 and a terminal device
21 are shown. A small cell 17A and a small cell 17B are included in
a small cell cluster 19A. A small cell 17C and a small cell 17D are
included in a small cell cluster 19B. The terminal device 21 is
connected to the macro base station 11.
[0113] In the macro cell 13, a CC0 is used by the macro base
station 11. Therefore, a CRS is transmitted by the macro base
station 11 in the CC0.
[0114] The small cell 17A is in the on state. A CC1 is used by the
small base station 15A in the small cell 17A. Therefore, in the
CC1, a CRS is transmitted by the small base station 15A.
[0115] The small cell 17B is in the off state and a CC2 is used by
the small base station 15B in the small cell 17B. Therefore, a DRS
is transmitted by the small base station 15B in the CC2.
[0116] The small cell 17C is in the on state and a CC3 is used by
the small base station 15C in the small cell 17C. Further, the
small cell 17D is in the off state and a CC3 is used by the small
base station 15D in the small cell 17D. Therefore, in the CC3, a
CRS is transmitted by the small base station 15C and a DRS is
transmitted by the small base station 15D.
[0117] FIG. 10 is a second explanatory diagram for describing an
example of measurement in a small cell on/off environment.
Referring to FIG. 10, a CRS is transmitted in a CC0, a CRS is
transmitted in a CC1, a DRS is transmitted in a CC2 and a CRS and a
DRS are transmitted in a CC3 identically to those described with
reference to FIG. 9. The terminal device 21 performs
intra-frequency measurement of the CC0. In addition, the terminal
device 21 performs inter-frequency measurement of the CC1, CC2 and
the CC3 using a measurement gap having a period of 40 ms or 80
ms.
[0118] As shown in the example, an inter-frequency measurement
frequency may increase when the number of CCs increases. In
addition, since a DRS is transmitted even when a small cell is in
the off state in the small cell on/off environment, an
inter-frequency measurement frequency may increase regardless of an
on/off state of the small cell. Alternatively, an inter-frequency
measurement frequency is maintained and, as a result,
inter-frequency measurement may consume much time.
[0119] In addition, it is necessary for the terminal device 21 to
perform inter-frequency measurement in consideration of a timing at
which a DRS is transmitted. Therefore, since inter-frequency
measurement based on a DRS whose transmission period is long has a
limited opportunity, the inter-frequency measurement based on a DRS
may consume much time.
[0120] In the embodiment of the present disclosure, it is possible
to improve inter-frequency measurement based on a DRS.
2. Schematic Configuration of Communication System
[0121] Next, a schematic configuration of a communication system 1
according to an embodiment of the present disclosure will be
described with reference to FIG. 11. FIG. 11 is an explanatory
diagram illustrating an example of a schematic configuration of the
communication system 1 according to an embodiment of the present
disclosure. As illustrated in FIG. 11, the communication system 1
includes a terminal device 100, a base station 200 and a control
entity 300. The communication system 1 is a system supporting, for
example, LTE, LTE-Advanced or a communication standard equivalent
thereto.
[0122] The terminal device 100 wirelessly communicates with the
base station 200. In addition, the terminal device 100 performs
measurement of each frequency band that is used by the base
station. In addition, the terminal device 100 reports a result of
the measurement to the base station 200.
[0123] The base station 200 wirelessly communicates with one or
more terminal devices including the terminal device 100. The base
station 200 may be a base station of a macro cell (that is, a macro
base station) or a base station of a small cell (that is, a small
base station).
[0124] The control entity 300 performs control according to each
embodiment of the present disclosure. The control entity 300 is,
for example, an existing or new core network node. Alternatively,
when the base station 200 is a small base station, the control
entity 300 may be a macro base station.
3. First Embodiment
[0125] Next, a first embodiment of the present disclosure will be
described with reference to FIG. 12 to FIG. 21.
[0126] A terminal device 100-1 according to the first embodiment
performs measurement of each of one or more frequency bands that
are a part of a plurality of frequency bands that are not used by
the terminal device 100-1. Specifically, according to the first
embodiment, the terminal device 100-1 does not perform measurement
of each of the remaining frequency bands among the plurality of
frequency bands or performs the measurement of each of the
remaining frequency bands at a frequency lower than a frequency of
the measurements of each of the one or more frequency bands.
Accordingly, for example, it is possible to improve measurement
performed by the terminal device 100-1. As a specific example, a
measurement load on the terminal device 100-1 may be reduced.
3.1. Configuration of Terminal Device
[0127] First, an example of a configuration of the terminal device
100-1 according to the first embodiment will be described with
reference to FIG. 12 to FIG. 15. FIG. 12 is a block diagram
illustrating an example of a configuration of the terminal device
100-1 according to the first embodiment. As illustrated in FIG. 12,
the terminal device 100-1 includes an antenna unit 110, a wireless
communication unit 120, a storage unit 130 and a processing unit
140.
(Antenna Unit 110)
[0128] The antenna unit 110 emits a signal output by the wireless
communication unit 120 into space as radio waves. In addition, the
antenna unit 110 converts spatial radio waves into a signal and
outputs the signal to the wireless communication unit 120.
(Wireless Communication Unit 120)
[0129] The wireless communication unit 120 transmits and receives
signals. For example, the wireless communication unit 120 receives
a downlink signal from a base station and transmits an uplink
signal to the base station.
(Storage Unit 130)
[0130] The storage unit 130 temporarily or permanently stores
programs and data for operations of the terminal device 100-1.
(Processing Unit 140)
[0131] The processing unit 140 provides various functions of the
terminal device 100-1. The processing unit 140 includes an
information acquiring unit 141, a measurement unit 143 and a
reporting unit 145. Alternatively, the processing unit 140 may
further include a component other than these components. That is,
the processing unit 140 may also perform an operation other than
operations of these components.
(Information Acquiring Unit 141)
[0132] The information acquiring unit 141 acquires information
about a frequency band.
[0133] For example, the information acquiring unit 141 acquires a
measurement configuration of a frequency band. For example, a base
station 200-1 transmits an RRC connection reconfiguration message
including the measurement configuration to the terminal device
100-1, and the information acquiring unit 141 acquires the
measurement configuration. The measurement configuration includes
information such as measurement objects, reporting configurations,
measurement identities (measurement IDs) and measurement gaps.
[0134] For example, the information acquiring unit 141 acquires a
neighboring cell list (NCL). For example, the information acquiring
unit 141 acquires an intra-frequency NCL and an inter-frequency
NCL. For example, the base station 200-1 informs the information
acquiring unit 141 of an intra-frequency NCL within a system
information block (SIB) 4, and the information acquiring unit 141
acquires the intra-frequency NCL. In addition, for example, the
base station 200-1 informs the information acquiring unit 141 of an
inter-frequency NCL within an SIB5, and the information acquiring
unit 141 acquires the inter-frequency NCL
(Measurement Unit 143)
[0135] The measurement unit 143 performs measurement of a frequency
band.
[0136] In the first embodiment, the measurement unit 143 performs
measurement of each of one or more frequency bands that are a part
of a plurality of frequency bands that are not used by the terminal
device 100-1. Conversely, the measurement unit 143 does not perform
measurement of each of the remaining frequency bands among the
plurality of frequency bands or performs the measurement of each of
the remaining frequency bands at a frequency lower than a frequency
of the measurements of each of the one or more frequency bands.
Accordingly, for example, it is possible to improve measurement
performed by the terminal device 100-1.
(a) Frequency Band
[0137] Component Carrier (CC)
[0138] For example, each of the plurality of frequency bands is a
component carrier (CC) of carrier aggregation.
[0139] The Same Operating Band
[0140] For example, the remaining frequency bands are frequency
bands included in the same operating band as the one or more
frequency bands. That is, the plurality of frequency bands are
included in a single operating band.
[0141] Accordingly, for example, general measurement of a
representative frequency band among a plurality of frequency bands
that are assumed to have similar characteristics (that is, a
plurality of frequency bands in a single operating band) is
performed. Therefore, for example, when there is a frequency band
through which favorable communication quality can be provided to
the terminal device 100-1, the terminal device 100-1 can use the
frequency band with a high probability while reducing a measurement
load
[0142] Further, for example, each of the remaining frequency bands
is a frequency band adjacent to any frequency band included in the
one or more frequency bands.
[0143] Accordingly, for example, general measurement of a
representative frequency band between two frequency bands that are
assumed to have fairly similar characteristics (that is, two
adjacent frequency bands) is performed. Therefore, for example,
when there is a frequency band through which favorable
communication quality can be provided to the terminal device 100-1,
the terminal device 100-1 can use the frequency band with a fairly
high probability while reducing a measurement load.
[0144] Frequency Band of Small Cell
[0145] For example, each of the plurality of frequency bands is a
frequency band that is used by a base station of a small cell.
[0146] Accordingly, for example, in an environment in which small
cells are arranged, it is possible to reduce a measurement
load.
[0147] The plurality of frequency bands have been described above.
The first embodiment is not limited thereto. For example, the
plurality of frequency bands may include frequency bands included
in a different operating band. In addition, the plurality of
frequency bands may include a frequency band that is used only by a
macro base station.
(b) Measurement
[0148] (b-1) Measurement Based on Reference Signal
[0149] For example, the measurement of each of the one or more
frequency bands is measurement based on a reference signal
transmitted in each of the one or more frequency bands. In
addition, the measurement of each of the remaining frequency bands
is measurement based on a reference signal transmitted in each of
the remaining frequency bands.
[0150] For example, the reference signal is a cell-specific
reference signal (CRS). Accordingly, for example, it is possible to
reduce a measurement load regarding a small cell in the on state. A
measurement load regarding a macro cell may also be reduced.
[0151] The measurement of each of the one or more frequency bands
is RRM measurement. For example, the measurement of each of the one
or more frequency bands is measurement of reception power or
reception quality. More specifically, for example, the measurement
of each of the one or more frequency bands is measurement of RSRP
or RSRQ. In addition, for example, the measurement of each of the
one or more frequency bands is performed for each cell in which
each of the one or more frequency bands is used (that is, a base
station that uses each of the one or more frequency bands).
(b-2) Measurement of Remaining Frequency Bands
First Example
Without Measurement
[0152] As a first example, the measurement unit 143 does not
perform the measurement of each of the remaining frequency bands.
Hereinafter, this will be described with reference to a specific
example of FIG. 13.
[0153] FIG. 13 is an explanatory diagram for describing a first
example of measurement according to the first embodiment. As
illustrated in FIG. 13, a CRS is transmitted in a CC0 and a CC1. In
this example, the terminal device 100-1 performs inter-frequency
measurement of the CC0. Conversely, inter-frequency measurement of
the CC1 is not performed.
[0154] Accordingly, for example, a frequency band that is a
measurement (that is, inter-frequency measurement) target is
limited. Therefore, it is possible to further decrease a frequency
of measurements performed by the terminal device 100-1. As a
result, a load of measurements performed by the terminal device
100-1 may be reduced. In addition, power consumption of the
terminal device 100-1 may decrease and throughput may be improved.
Alternatively, measurement of a specific frequency band can be
intensively performed for a short period. As a result, measurement
of the specific frequency band may be performed more quickly.
Second Example
Measurement at Low Frequency
[0155] As a second example, the measurement unit 143 performs the
measurement of each of the remaining frequency bands at a frequency
lower than a frequency of the measurements of each of the one or
more frequency bands.
[0156] More specifically, for example, the measurement unit 143
performs the measurement of each of the remaining frequency bands
using fewer measurement gaps than measurement gaps used for the
measurement of each of the one or more frequency bands.
[0157] As an example, the measurement unit 143 skips a part of the
measurement gaps assigned to each of the remaining frequency bands
without measurement. Hereinafter, this will be described with
reference to a specific example of FIG. 14.
[0158] FIG. 14 is an explanatory diagram for describing a second
example of measurement according to the first embodiment. As
illustrated in FIG. 14, a CRS is transmitted in a CC0 and a CC1. In
this example, the same number of measurement gaps is assigned to
the CC0 and CC1. The terminal device 100-1 performs measurement of
the CC0 using all measurement gaps assigned to the CC0. Conversely,
the terminal device 100-1 skips a part of all measurement gaps
assigned to the CC1 without measurement of the CC1, and performs
measurement of the CC1 using the rest of the all measurement gaps
assigned to the CC1.
[0159] Accordingly, for example, a frequency of measurements
performed by the terminal device 100-1 (that is, inter-frequency
measurement) decreases. As a result, a load of measurements
performed by the terminal device 100-1 may be reduced. In addition,
power consumption of the terminal device 100-1 may decrease and
throughput may be improved.
[0160] As another example, measurement gaps assigned to each of the
remaining frequency bands may be fewer than measurement gaps
assigned to each of the one or more frequency bands. Hereinafter,
this will be described with reference to a specific example of FIG.
15
[0161] FIG. 15 is an explanatory diagram for describing a third
example of measurement according to the first embodiment. As
illustrated in FIG. 15, a CRS is transmitted in a CC0 and a CC1. In
this example, more measurement gaps are assigned to the CC0 and
fewer measurement gaps are assigned to the CC1. The terminal device
100-1 performs measurement of the CC0 using the more measurement
gaps assigned to the CC0, and performs measurement of the CC1 using
the fewer measurement gaps assigned to the CC1.
[0162] Accordingly, for example, measurement of a specific
frequency band can be intensively performed for a short period. As
a result, measurement of the specific frequency band may be
performed more quickly.
[0163] The measurement of each of the remaining frequency bands is
RRM measurement. For example, the measurement of each of the
remaining frequency bands is measurement of reception power or
reception quality. More specifically, for example, the measurement
of each of the remaining frequency bands is measurement of RSRP or
RSRQ. In addition, for example, the measurement of each of the
remaining frequency bands is performed for each cell in which each
of the remaining frequency bands is used (that is, a base station
that uses each of the remaining frequency bands).
(c) Measurement Control
[0164] For example, the measurement by the measurement unit 143 is
performed according to an instruction from the base station 200-1.
That is, the terminal device 100-1 performs the measurement by the
measurement unit 143 according to an instruction from the base
station 200-1
[0165] The measurement by the measurement unit 143 may be
voluntarily performed. That is, the terminal device 100-1 may
voluntarily perform the measurement by the measurement unit 143. In
this case, the base station 200-1 may not perform some or all of
operations which will be described.
(Reporting unit 145)
[0166] The Reporting Unit 145 Reports a Result of the Measurement
of a Frequency band to the base station 200-1.
(a) Reporting of Result of Measurement of One or More Frequency
Bands
[0167] The reporting unit 145 reports a result of the measurement
of each of the one or more frequency bands to the base station
200-1.
(b) Reporting of Result of Measurement of Remaining Frequency
Bands
First Example
Without Measurement
[0168] As described above, as a first example, the measurement unit
143 does not perform the measurement of each of the remaining
frequency bands. In this case, the reporting unit 145 does not
report a result of the measurement of each of the remaining
frequency bands to the base station 200-1.
[0169] The reporting unit 145 may substitute a result of
measurement of a first frequency band included in the one or more
frequency bands with a result of measurement of a second frequency
band included in the remaining frequency bands, and thus may report
the result of the measurement of the second frequency band to the
base station 200-1. Accordingly, for example, a frequency band that
is not actually measured may be selected as a frequency band that
is used by the terminal device 100-1.
Second Example
Measurement at Low Frequency
[0170] As described above, as the second example, the measurement
unit 143 performs the measurement of each of the remaining
frequency bands at a frequency lower than a frequency of the
measurements of each of the one or more frequency bands. In this
case, the reporting unit 145 reports a result of the measurement of
each of the remaining frequency bands to the base station 200-1
(c) Reporting Method
[0171] For example, the reporting unit 145 reports a result of
measurement to the base station 200-1 according to a reporting
configuration included in the measurement configuration from the
base station 200-1.
[0172] For example, the reporting unit 145 reports the result of
the measurement to the base station 200-1 through the antenna unit
110 and the wireless communication unit 120.
3.2. Configuration of Base Station
[0173] Next, an example of a configuration of the base station
200-1 according to the first embodiment will be described with
reference to FIG. 16. FIG. 16 is a block diagram illustrating an
example of a configuration of the base station 200-1 according to
the first embodiment. Referring to FIG. 16, the base station 200-1
includes an antenna unit 210, a wireless communication unit 220, a
network communication unit 230, a storage unit 240, and a
processing unit 250.
(Antenna Unit 210)
[0174] The antenna unit 210 radiates a signal output from the
wireless communication unit 220 into the air as radio waves. The
antenna unit 210 converts the radio waves in the air into a signal,
and outputs the signal to the wireless communication unit 220.
(Wireless Communication Unit 220)
[0175] The wireless communication unit 220 transmits or receives a
signal. For example, the wireless communication unit 220 transmits
the downlink signal to the terminal device, and receives the uplink
signal from the terminal device.
(Network Communication Unit 230)
[0176] The network communication unit 230 communicates with other
nodes. For example, the network communication unit 230 communicates
with a core network node and other base stations. For example, the
network communication unit 230 communicates with a control entity
300-1.
(Storage Unit 240)
[0177] The storage unit 240 temporarily or permanently stores a
program and data for an operation of the base station 200-1.
(Processing Unit 250)
[0178] The processing unit 250 provides various functions of the
base station 200-1. The processing unit 250 includes an information
acquiring unit 251 and a control unit 253. The processing unit 250
may further include any other component in addition to the
above-mentioned components. In other words, the processing unit 250
may also perform an operation other than operations of the
above-mentioned components.
(Information Acquiring Unit 251)
[0179] The information acquiring unit 251 acquires information
about a plurality of frequency bands that are not used by the
terminal device 100-1.
[0180] Descriptions of the plurality of frequency bands are the
same as those described above in the measurement unit 143 of the
terminal device 100-1. Therefore, redundant descriptions will be
omitted here
[0181] The information about the plurality of frequency bands
includes information indicating each of the plurality of frequency
bands (for example, a downlink carrier frequency or identification
information)
(Control Unit 253)
[0182] The control unit 253 instructs the terminal device 100-1 to
perform measurement of each of one or more frequency bands that are
a part of the plurality of frequency bands, and not to perform
measurement of each of the remaining frequency bands among the
plurality of frequency bands or perform the measurement of each of
the remaining frequency bands at a frequency lower than a frequency
of the measurements of each of the one or more frequency bands.
(a) Frequency Band
[0183] For example, the control unit 253 selects the one or more
frequency bands from among the plurality of frequency bands.
Alternatively, the control unit 253 may select the remaining
frequency bands other than the one or more frequency bands from
among the plurality of frequency bands.
[0184] Descriptions of the one or more frequency bands and the
remaining frequency bands are the same as those described above in
the measurement unit 143 of the terminal device 100-1. Therefore,
redundant descriptions will be omitted here.
(b) Measurement of Remaining Frequency Bands
(b-1) First Example
Without Measurement
[0185] As a first example, the control unit 253 instructs the
terminal device 100-1 to perform the measurement of each of the one
or more frequency bands and not to perform measurement of each of
the remaining frequency bands among the plurality of frequency
bands.
[0186] The control unit 253 may substitute a result of measurement
of a first frequency band included in the one or more frequency
bands with a result of measurement of a second frequency band
included in the remaining frequency bands.
[0187] For example, the control unit 253 substitutes a result of
measurement of the first frequency band with a result of
measurement of the second frequency band and thus may perform a
handover decision. As an example, the second frequency band may be
a frequency band that is adjacent to the first frequency band.
Accordingly, for example, a frequency band that is not actually
measured may be selected as a frequency band that is used by the
terminal device 100-1.
(b-2) Second Example
Measurement at Low Frequency
[0188] As a second example, the control unit 253 instructs the
terminal device 100-1 to perform the measurement of each of the
remaining frequency bands at a frequency lower than a frequency of
the measurements of each of the one or more frequency bands.
[0189] As a specific example, the control unit 253 instructs the
terminal device 100-1 to perform the measurement of each of the
remaining frequency bands using fewer measurement gaps than
measurement gaps used for the measurement of each of the one or
more frequency bands.
[0190] As an example, the control unit 253 instructs the terminal
device 100-1 to skip a part of measurement gaps assigned to each of
the remaining frequency bands without measurement.
[0191] As another example, the control unit 253 may instruct the
terminal device 100-1 to assign fewer measurement gaps to each of
the remaining frequency bands than to each of the one or more
frequency bands. Alternatively, the control unit 253 may decide
measurement gap assignment such that the measurement gaps assigned
to each of the remaining frequency bands are fewer than measurement
gaps assigned to each of the one or more frequency bands. Thus, the
control unit 253 may instruct the terminal device 100-1 to perform
the decided assignment.
(c) Specific Process
[0192] For example, the control unit 253 performs an instruction
according to individual signaling to the terminal device 100-1. For
example, the individual signaling is RRC signaling.
[0193] As an example, the control unit 253 may transmit an RRC
connection reconfiguration message including a measurement
configuration through the antenna unit 210 and the wireless
communication unit 220, and thus may perform the instruction.
3.3. Process Flow
[0194] Next, examples of processes according to the first
embodiment will be described with reference to FIG. 17 and FIG.
18.
First Example
Without Measurement
[0195] FIG. 17 is a sequence diagram illustrating a first example
of a schematic flow of a process according to the first
embodiment.
[0196] The base station 200-1 (the information acquiring unit 251)
acquires information about a plurality of frequency bands that are
not used by the terminal device 100-1 (S401).
[0197] Then, the base station 200-1 (the control unit 253)
instructs the terminal device 100-1 to perform measurement of each
of one or more frequency bands that are a part of the plurality of
frequency bands and not to perform measurement of each of the
remaining frequency bands among the plurality of frequency bands
(S403).
[0198] Then, the terminal device 100-1 (the measurement unit 143)
performs measurement of each of the one or more frequency bands
(S405). The terminal device 100-1 (the measurement unit 143) does
not perform measurement of each of the remaining frequency
bands.
[0199] Then, the terminal device 100-1 (the reporting unit 145)
reports a result of the measurement to the base station 200-1
(S407).
Second Example
Measurement at Low Frequency
[0200] FIG. 18 is a sequence diagram illustrating a second example
of a schematic flow of a process according to the first
embodiment.
[0201] The base station 200-1 (the information acquiring unit 251)
acquires information about a plurality of frequency bands that are
not used by the terminal device 100-1 (S411).
[0202] Then, the base station 200-1 (the control unit 253)
instructs the terminal device 100-1 to perform measurement of each
of one or more frequency bands that are a part of the plurality of
frequency bands and perform measurement of each of the remaining
frequency bands among the plurality of frequency bands at a
frequency lower than a frequency of the measurements of each of the
one or more frequency bands (S413)
[0203] Then, the terminal device 100-1 (the measurement unit 143)
performs measurement of each of the one or more frequency bands,
and performs the measurement of each of the remaining frequency
bands at a frequency lower than a frequency of the measurements of
each of the one or more frequency bands (S415)
[0204] Then, the terminal device 100-1 (the reporting unit 145)
reports a result of the measurement to the base station 200-1
(S417).
3.4. Modification Example
[0205] Next, a modification example of the first embodiment will be
described with reference to FIG. 19 to FIG. 21.
[0206] As described above, for example, the measurement of each of
the one or more frequency bands is measurement based on a reference
signal transmitted in each of the one or more frequency bands. In
addition, the measurement of each of the remaining frequency bands
is measurement based on a reference signal transmitted in each of
the remaining frequency bands. In addition, in the above-described
example of the first embodiment, the reference signal is a CRS.
Conversely, in the modification example of the first embodiment,
the reference signal is a discovery reference signal (DRS).
(Terminal Device 100-1: Measurement Unit 143)
(b) Measurement
[0207] (b-1) Measurement Based on Reference Signal
[0208] As described above, for example, the measurement of each of
the one or more frequency bands is measurement based on a reference
signal transmitted in each of the one or more frequency bands. In
addition, the measurement of each of the remaining frequency bands
is measurement based on a reference signal transmitted in each of
the remaining frequency bands.
[0209] Specifically, in the modification example of the first
embodiment, the reference signal is a discovery reference signal
(DRS). Accordingly, for example, it is possible to reduce a
measurement load regarding a small cell in the off state.
[0210] The DRS is a reference signal that is transmitted by a base
station of the small cell in an off state. The DRS may also be
referred to as a discovery signal (DR).
(b-2) Measurement of Remaining Frequency Bands
First Example
Without Measurement
[0211] As a first example, the measurement unit 143 does not
perform the measurement of each of the remaining frequency bands.
Hereinafter, this will be described with reference to a specific
example of FIG. 19.
[0212] FIG. 19 is an explanatory diagram for describing a first
example of measurement according to a modification example of the
first embodiment. As illustrated in FIG. 19, a DRS is transmitted
in a CC0 and a CC1. In this example, in the terminal device 100-1,
inter-frequency measurement of the CC0 is performed
[0213] Conversely, inter-frequency measurement of the CC1 is not
performed.
Second Example
Measurement at Low Frequency
[0214] As a second example, the measurement unit 143 performs the
measurement of each of the remaining frequency bands at a frequency
lower than a frequency of the measurements of each of the one or
more frequency bands.
[0215] As an example, the measurement unit 143 skips a part of
measurement gaps assigned to each of the remaining frequency bands
without measurement Hereinafter, this will be described with
reference to a specific example of FIG. 20.
[0216] FIG. 20 is an explanatory diagram for describing a second
example of measurement according to a modification example of the
first embodiment. As illustrated in FIG. 20, a DRS is transmitted
in a CC0 and a CC1. In this example, the same number of measurement
gaps is assigned to the CC0 and the CC1. The terminal device 100-1
performs measurement of the CC0 using all measurement gaps assigned
to the CC0. Conversely, the terminal device 100-1 skips a part of
all measurement gaps assigned to the CC1 without measurement of the
CC1 and performs measurement of the CC1 using the rest of the all
measurement gaps assigned to the CC1.
[0217] As another example, measurement gaps assigned to each of the
remaining frequency bands may be fewer than measurement gaps
assigned to each of the one or more frequency bands. Hereinafter,
this will be described with reference to a specific example of FIG.
21.
[0218] FIG. 21 is an explanatory diagram for describing a third
example of measurement according to a modification example of the
first embodiment. As illustrated in FIG. 21, a DRS is transmitted
in a CC0 and a CC1. In this example, more measurement gaps are
assigned to the CC0 and fewer measurement gaps are assigned to the
CC1. The terminal device 100-1 performs measurement of the CC0
using the more measurement gaps assigned to the CC0, and performs
measurement of the CC1 using the fewer measurement gaps assigned to
the CC1.
4. Second Embodiment
[0219] Next, a second embodiment of the present disclosure will be
described with reference to FIG. 22 to FIG. 30.
[0220] A terminal device 100-2 according to the second embodiment
performs measurement of a first frequency band based on a discovery
reference signal transmitted in the first frequency band within a
first period included in a measurement gap, and performs
measurement of a second frequency band based on a reference signal
transmitted in the second frequency band within a second period
included in the measurement gap. Specifically, in the second
embodiment, the reference signal transmitted in the second
frequency band is a DRS. That is, in the second embodiment, the
terminal device 100-2 performs measurement of a frequency group
including the first frequency band and the second frequency band
using the measurement gap. Accordingly, for example, it is possible
to improve measurement performed by a terminal device 100-3.
4.1. Configuration of Terminal Device
[0221] First, an example of a configuration of the terminal device
100-2 according to the second embodiment will be described with
reference to FIG. 22 to FIG. 25. FIG. 22 is a block diagram
illustrating an example of a configuration of the terminal device
100-2 according to the second embodiment. As illustrated in FIG.
22, the terminal device 100-2 includes the antenna unit 110 the
wireless communication unit 120, the storage unit 130 and a
processing unit 150.
[0222] There is no difference in descriptions of the antenna unit
110, the wireless communication unit 120 and the storage unit 130
between the first embodiment and the second embodiment except for
different reference numerals. Therefore, redundant descriptions
will be omitted here, and only the processing unit 150 will be
described.
(Processing Unit 150)
[0223] The processing unit 150 provides various functions of the
terminal device 100-2. The processing unit 150 includes an
information acquiring unit 151, a measurement unit 153 and a
reporting unit 155. The processing unit 150 may further include a
component other than these components. That is, the processing unit
150 may also perform an operation other than operations of these
components.
(Information Acquiring Unit 151)
[0224] The information acquiring unit 151 acquires information
indicating a first frequency band in which a DRS is transmitted
within at least a first period included in a measurement gap.
Specifically, in the second embodiment, the information acquiring
unit 151 acquires information indicating a frequency group
including the first frequency band and a second frequency band. For
example, the second frequency band is a frequency band in which a
DRS is transmitted within at least a second period included in the
measurement gap.
[0225] In addition, the information acquiring unit 151 acquires
information indicating the measurement gap.
[0226] For example, a base station 200-2 notifies the terminal
device 100-2 of the frequency group and the measurement gap. As a
specific example, the base station 200-2 transmits information
indicating the frequency group and information indicating the
measurement gap to the terminal device 100-2. As an example, the
base station 200-2 transmits an RRC connection reconfiguration
message including a measurement configuration including the
information indicating the frequency group and the information
indicating the measurement gap to the terminal device 100-2. Then,
the information acquiring unit 151 acquires the information
indicating the frequency group and the information indicating the
measurement gap.
(Measurement Unit 153)
[0227] The measurement unit 153 performs measurement of a frequency
band.
[0228] In the second embodiment, the measurement unit 153 performs
measurement of a first frequency band based on a DRS transmitted in
the first frequency band within a first period included in a
measurement gap. In addition, the measurement unit 153 performs
measurement of a second frequency band based on a reference signal
transmitted in the second frequency band within a second period
included in the measurement gap. Accordingly, for example, it is
possible to improve measurement performed by the terminal device
100-3.
(a) Frequency Band
[0229] Component Carrier (CC)
[0230] For example, the first frequency band and the second
frequency band each are component carriers (CCs) of carrier
aggregation.
[0231] Frequency Band of Small Cell
[0232] For example, each of the first frequency band and the second
frequency band is a frequency band that is used by a base station
of a small cell
[0233] Frequency Band that is not Used
[0234] For example, each of the first frequency band and the second
frequency band is a frequency band that is not used by the terminal
device 100-2
[0235] In view of the above points, for example, each of the first
frequency band and the second frequency band is a CC that is used
by a base station of a small cell, and the CC is not used by the
terminal device 100-2
(b) Measurement
[0236] The measurement of the first frequency band and the
measurement of the second frequency band are RRM measurements, for
example, measurements of reception power or reception quality. As a
specific example, the measurement of the first frequency band and
the measurement of the second frequency band are measurements of
RSRP or RSRQ.
[0237] In addition, for example, measurement is performed in units
of a combination of a frequency band and a cell (a base station).
For example, the measurement of the first frequency band is
performed for each cell in which the first frequency band is used
(that is, a base station that uses the first frequency band). In
addition, for example, the measurement of the second frequency band
is performed for each cell in which the second frequency band is
used (that is, a base station that uses the second frequency
band).
(c) Reference Signal
[0238] Specifically, in the second embodiment, the reference signal
transmitted in the second frequency band is a DRS. That is, the
measurement unit 153 performs measurement of the first frequency
band and the second frequency band in which a DRS is transmitted
using the measurement gap.
[0239] The DRS is a reference signal that is transmitted by a base
station of a small cell in the off state. The DRS may also be
referred to as a discovery signal (DR).
(d) Measurement Gap
[0240] For example, the measurement gap is a period having a length
of 6 milliseconds. That is, the measurement gap is a general
measurement gap.
[0241] For example, each of the first period and the second period
is a period shorter than 6 milliseconds. That is, a shorter period
is used for measurement based on a DRS than general measurement
based on a CRS.
(e) Specific Example of Measurement
[0242] Hereinafter, a first example of measurement according to the
second embodiment will be described with reference to FIG. 23.
[0243] FIG. 23 is an explanatory diagram for describing a first
example of measurement according to the second embodiment.
Referring to FIG. 23, a measurement gap having a length of 6
subframes is shown. In this example, the measurement unit 153
performs measurement of a CC1 based on a DRS transmitted in the CC1
(a first frequency band) within a period (a first period) from a
1st subframe to a 3rd subframe within the measurement gap. In
addition, the measurement unit 153 performs measurement of a CC2
based on a DRS transmitted in the CC2 (a second frequency band)
within a period (a second period) from a 4th subframe to a 6th
subframe within the measurement gap.
[0244] When measurement of the first frequency band and measurement
of the second frequency band are collectively performed using the
measurement gap, for example, it is possible to perform measurement
of the first frequency band and measurement of the second frequency
band using fewer measurement gaps. Therefore, measurement based on
a DRS (that is, inter-frequency measurement of a frequency band
that is used by a base station of a small cell) may be efficiently
performed. As a specific example, measurement based on a DRS may be
performed more quickly.
[0245] In addition, as described above, when measurement based on a
DRS is performed using a short period, it is possible to actually
perform measurement of two frequency bands (or two or more
frequency bands) using the same measurement gap.
(f) Measurement of Additional Frequency Band
[0246] The measurement gap may include an additional period. The
measurement unit 153 may perform measurement of an additional
frequency band based on a DRS transmitted in the additional
frequency band within the additional period. Hereinafter, this will
be described with reference to a specific example of FIG. 24.
[0247] FIG. 24 is an explanatory diagram for describing a second
example of measurement according to the second embodiment.
Referring to FIG. 24, a measurement gap having a length of 6
subframes is shown. In this example, the measurement unit 153
performs measurement of a CC1 based on a DRS transmitted in the CC1
(a first frequency band) within a period (a first period) including
a 1st subframe and a 2nd subframe within the measurement gap. In
addition, the measurement unit 153 performs measurement of a CC2
based on a DRS transmitted in the CC2 (a second frequency band)
within a period (a second period) including a 3rd subframe and a
4th subframe within the measurement gap. Further, the measurement
unit 153 performs measurement of a CC3 based on a DRS transmitted
in the CC3 (an additional frequency band) within a period (an
additional period) including a 5th subframe and a 6th subframe
within the measurement gap.
[0248] Accordingly, measurement based on a DRS (that is,
inter-frequency measurement) may be further efficiently
performed.
[0249] While an example in which the measurement gap includes one
additional period and the measurement unit 153 performs measurement
of one additional frequency band has been described, it should be
understood that the second embodiment is not limited thereto. The
measurement gap may include two or more additional periods and the
measurement unit 153 may perform measurement of two or more
additional frequency bands.
(g) Measurement Based on CRS and DRS
[0250] The measurement unit 153 may perform the measurement of the
first frequency band that is used by the same base station based on
a DRS and a CRS transmitted by the same base station in the first
frequency band within the first period Additionally or
alternatively, the measurement unit 153 may perform the measurement
of the second frequency band that is used by the same base station
based on a DRS and a CRS transmitted by the same base station in
the second frequency band within the second period. In this case,
the first period may be a period shorter than 6 milliseconds.
[0251] As a specific example, a base station of a small cell in the
on state transmits both a DRS and a CRS in the first frequency
band. In this case, the measurement unit 153 may perform
measurement of the first frequency band that is used by the base
station based on the DRS and the CRS transmitted by the base
station in the first frequency band within the first period.
Hereinafter, hereinafter, this will be described with reference to
a specific example of FIG. 25.
[0252] FIG. 25 is an explanatory diagram for describing a third
example of measurement according to the second embodiment.
Referring to FIG. 25, a measurement gap having a length of 6
subframes is shown. In this example, the measurement unit 153
performs measurement of a CC1 based on a DRS and a CRS transmitted
by the same base station using the CC1 (a first frequency band)
within a period (a first period) from a 1st subframe to a 4th
subframe within the measurement gap. In addition, the measurement
unit 153 performs measurement of a CC2 based on a DRS transmitted
in the CC2 (a second frequency band) within a period (a second
period) including a 5th subframe and a 6th subframe within the
measurement gap.
[0253] Accordingly, for example, measurement of the first frequency
band or the second frequency band (that is, inter-frequency
measurement) is performed based on more reference signals.
Therefore, the measurement of the first frequency band or the
second frequency band used by the base station may be performed
using a shorter period than when it is performed based on only a
CRS. Therefore, measurement of the first frequency band and
measurement of the second frequency band (that is, measurement of a
frequency band that is used by a base station of a small cell in
the on state and measurement of a frequency band that is used by a
base station of another small cell) may be performed using the same
measurement gap.
(h) Priority
[0254] Measurement Based on Priority
[0255] For example, the measurement unit 153 performs measurement
of a frequency group and measurement of one or more other frequency
bands or measurement of one or more other frequency groups based on
a priority of the frequency group including the first frequency
band and the second frequency band and a priority of the one or
more other frequency bands or a priority of the one or more other
frequency groups.
[0256] As a specific example, a frequency group or a frequency band
having a higher priority is sequentially selected from among the
frequency group including the first frequency band and the second
frequency band, the one or more other frequency bands, and the one
or more other frequency groups. Then, the measurement unit 153
performs measurement of the selected frequency group or frequency
band
[0257] As an example, the priority of the frequency band is a
priority included in an inter-frequency NCL contained in the SIB5.
As another example, the priority of the frequency band may be a
priority that is decided by the terminal device 100-2.
[0258] The priority of the frequency group (and/or a priority of
each of the one or more other frequency groups) may be decided in
consideration of power consumption and/or a communication request
of the terminal device 100-2. As an example, when suppression of
power consumption is requested, the priority of the frequency group
may be higher. This is because, when the priority of the frequency
group is high, measurement of more frequency bands is performed
using a measurement gap. As another example, when high throughput
is requested, the priority of the frequency group may be lower.
This is because, when the priority of the frequency group is low,
measurement of a frequency band that is used by a base station of a
cell in the on state is preferentially performed, and, as a result,
a handover is preferentially performed without a transition
time.
[0259] Measurement in Consideration of Transmission Period of
DRS
[0260] For example, the measurement unit 153 performs the
measurement of the frequency group, and the measurement of the one
or more other frequency bands or the measurement of the one or more
other frequency groups in consideration of a transmission period in
which a DRS is transmitted in the first frequency band. As a
specific example, the measurement unit 153 performs measurement of
another frequency band or another frequency group whose priority is
lower than the frequency group before the measurement of the
frequency group outside of the transmission period.
[0261] Accordingly, for example, measurement may be performed more
smoothly without wasting the measurement gap.
(Reporting Unit 155)
[0262] The reporting unit 155 reports a result of measurement of
the frequency band to the base station 200-2.
[0263] For example, the reporting unit 155 reports a result of
measurement of the first frequency band to the base station 200-2.
In addition, for example, the reporting unit 155 reports a result
of measurement of the second frequency band to the base station
200-2. In addition, the frequency group may include an additional
frequency band, and the reporting unit 155 may report a result of
measurement of the additional frequency band to the base station
200-2.
4.2. Configuration of Base Station
[0264] Next, an example of a configuration of the base station
200-2 according to the second embodiment will be described with
reference to FIG. 26. FIG. 26 is a block diagram illustrating an
example of a configuration of the base station 200-2 according to
the second embodiment. Referring to FIG. 26, the base station 200-2
includes an antenna unit 210, a wireless communication unit 220, a
network communication unit 230, a storage unit 240, and a
processing unit 260.
[0265] There is no difference in descriptions of the antenna unit
210, the wireless communication unit 220, the network communication
unit 230 and the storage unit 240 between the first embodiment and
the second embodiment except for different reference numerals.
Therefore, redundant descriptions will be omitted here, and only
the processing unit 260 will be described.
(Processing Unit 260)
[0266] The processing unit 260 provides various functions of the
base station 200-2. The processing unit 260 includes an information
acquiring unit 261 and a control unit 263. The processing unit 260
may further include any other component in addition to the
above-mentioned components. In other words, the processing unit 260
may also perform an operation other than operations of the
above-mentioned components.
(Information Acquiring Unit 261)
(a) Frequency Group
[0267] The information acquiring unit 261 acquires information
indicating a first frequency band in which a DRS is transmitted
within at least a first period included in a measurement gap
[0268] For example, the measurement gap further includes a second
period in which a reference signal is transmitted in a second
frequency band.
[0269] Specifically, in the second embodiment, the information
acquiring unit 261 acquires information indicating the frequency
group including the first frequency band and the second frequency
band. The second frequency band is a frequency band in which a DRS
is transmitted within at least a second period included in the
measurement gap
[0270] More specifically, for example, a control entity 300-2
decides the frequency group and notifies the base station 200-2 of
the frequency group. Then, the information indicating the frequency
group is stored in the storage unit 240 The information acquiring
unit 261 acquires the information indicating the frequency group at
any time thereafter.
(b) Measurement Gap
[0271] Further, for example, the information acquiring unit 261
acquires information indicating the measurement gap.
[0272] More specifically, for example, the control entity 300-2
decides the measurement gap and notifies the base station 200-2 of
the measurement gap. Then, information indicating the measurement
gap is stored in the storage unit 240. The information acquiring
unit 261 acquires the information indicating the measurement gap at
any time thereafter.
[0273] Alternatively, the measurement gap is decided by a device
other than the control entity 300-2 and the base station 200-2 may
be notified thereof. Alternatively, the measurement gap is decided
by the base station 200-2, and may be stored in the storage unit
240.
(Control Unit 263)
(a) Notification of Frequency Group and Measurement Gap
[0274] The control unit 263 notifies the terminal device 100-2 of
the first frequency band and the measurement gap. Specifically, in
the second embodiment, the control unit 263 notifies the terminal
device 100-2 of the frequency group including the first frequency
band and the second frequency band and the measurement gap.
[0275] As a specific example, the control unit 263 transmits
information indicating the frequency group and information
indicating the measurement gap to the terminal device 100-2 through
the antenna unit 210 and the wireless communication unit 220. As an
example, the control unit 263 transmits an RRC connection
reconfiguration message including a measurement configuration
including the information indicating the frequency group and the
information indicating the measurement gap to the terminal device
100-2 through the antenna unit 210 and the wireless communication
unit 220.
(b) Priority Notification
[0276] For example, the control unit 263 notifies the terminal
device 100-2 of a priority of the frequency group and a priority of
one or more other frequency bands or a priority of one or more
other frequency groups.
[0277] As a specific example, the control unit 263 transmits
information indicating the priority of the frequency group and the
priority of one or more other frequency bands or the priority of
one or more other frequency groups to the terminal device 100-2
through the antenna unit 210 and the wireless communication unit
220. As an example, the information is included in the
inter-frequency NCL within the SIB5, and the control unit 263
informs the terminal device 100-2 of the SIB5 including the
inter-frequency NCL through the antenna unit 210 and the wireless
communication unit 220.
4.3. Configuration of Control Entity
[0278] Next, an example of a configuration of the control entity
300-2 according to the second embodiment will be described with
reference to FIG. 27. FIG. 27 is a block diagram illustrating an
example of a configuration of the control entity 300-2 according to
the second embodiment. Referring to FIG. 27, the control entity
300-2 includes a communication unit 310, a storage unit 320, and a
processing unit 330.
(Communication Unit 310)
[0279] The communication unit 310 communicates with other nodes.
For example, the communication unit 310 communicates with a core
network node and a base station. For example, the communication
unit 310 communicates with the base station 200-2.
(Storage Unit 320)
[0280] The storage unit 320 temporarily or permanently stores a
program and data for an operation of the control entity 300-2.
(Processing Unit 330)
[0281] The processing unit 330 provides various functions of the
control entity 300-2. The processing unit 330 includes an
information acquiring unit 331 and a control unit 333. The
processing unit 330 may further include any other component in
addition to the above-mentioned components. In other words, the
processing unit 330 may also perform an operation other than
operations of the above-mentioned components.
(Information Acquiring Unit 331)
[0282] The information acquiring unit 331 acquires information
about two or more frequency bands in which a DRS is
transmitted.
[0283] Each of the two or more frequency bands is a frequency band
that is used by a base station of a small cell. When a base station
of a small cell in the off state transmits a DRS and a base station
of a small cell in the on state does not transmit a DRS, each of
the two or more frequency bands is a frequency band that is used by
the base station of the small cell in the off state. Conversely,
when a base station of a small cell transmits a DRS regardless of
an on/off state, each of the two or more frequency bands is a
frequency band that is used by the base station of the small
cell.
(Control Unit 333)
(a) Decision of Frequency Group
[0284] The control unit 333 decides a frequency group including at
least a first frequency band and a second frequency band among the
two or more frequency bands.
[0285] The first frequency band is a frequency band in which a DRS
is transmitted within at least a first period included in a
measurement gap. In addition, the second frequency band is a
frequency band in which a DRS is transmitted within at least a
second period included in the measurement gap.
[0286] In addition, for example, the control unit 333 decides the
measurement gap.
(a-1) First Method
[0287] For example, as a first method, the control unit 333
controls a transmission period in which a DRS is transmitted in a
first frequency band such that the DRS is transmitted in the first
frequency band within at least the first period or controls a
transmission period in which a DRS is transmitted in a second
frequency band such that the DRS is transmitted in the second
frequency band within at least the second period.
[0288] More specifically, for example, the control unit 333 decides
a frequency group including at least the first frequency band and
the second frequency band among the two or more frequency bands.
For example, the frequency group is any frequency band among the
two or more frequency bands and the number thereof is equal to or
less than a predetermined maximum number. For example, when a
measurement gap has a length of M subframes (for example, 6
subframes) and a period used for measurement based on a DRS is N
subframes (for example, 3 subframes), the predetermined maximum
number is M/N (for example, 2). Further, the control unit 333
decides the measurement gap. Then, the control unit 333 instructs a
base station that transmits a DRS in each of the frequency bands
included in the frequency group to transmit the DRS during the
measurement gap. For example, the control unit 333 instructs a base
station that transmits a DRS in the first frequency band and a base
station that transmits a DRS in the second frequency band to
transmit the DRSs during the measurement gap.
[0289] Accordingly, for example, it is possible to more reliably
perform measurement of two or more frequency bands using the same
measurement gap.
(a-2) Second Method
[0290] As a second method, the information about the two or more
frequency bands (that is, information acquired by the information
acquiring unit 331) may include information indicating a
transmission period in which a DRS is transmitted in each of the
two or more frequency bands. Then, the control unit 333 may decide
the frequency group based on the transmission period.
[0291] More specifically, for example, based on the information
indicating a transmission period in which a DRS is transmitted in
each of the two or more frequency bands, the control unit 333
decides at least two frequency bands whose transmission periods of
the DRSs are the same (or similar) among the two or more frequency
bands as a frequency group. The control unit 333 decides frequency
bands whose number is equal to or less than a predetermined maximum
number as a frequency group. In addition, the control unit 333
decides a measurement gap that overlaps the transmission period of
the DRS.
[0292] Accordingly, for example, it is possible to perform
measurement of each of the two or more frequency bands using the
same measurement gap without the control entity 300-2 instructing a
base station.
(b) Provide Notification to Base Station 200-2
[0293] For example, the control unit 333 notifies the base station
200-2 of the frequency group. In addition, for example, the control
unit 333 notifies the base station 200-2 of the measurement
gap.
[0294] As a specific example, the control unit 333 transmits a
message including information indicating the frequency group and
information indicating the measurement gap to the base station
200-2 through the communication unit 310.
4.4. Process Flow
[0295] Next, examples of processes according to the second
embodiment will be described with reference to FIG. 28 to FIG.
30.
(Overall Process Flow)
[0296] FIG. 28 is a sequence diagram illustrating an example of a
schematic flow of a process according to the second embodiment.
[0297] The control entity 300-2 performs a frequency group decision
process (S430). That is, the control entity 300-2 (the control unit
333) decides a frequency group including at least a first frequency
band and a second frequency band among two or more frequency bands
in which a DRS is transmitted. In addition, for example, the
control entity 300-2 decides a measurement gap that is used for
measurement of the frequency group.
[0298] Then, the control entity 300-2 notifies the base station
200-2 of the frequency group and the measurement gap (S451).
[0299] Further, the base station 200-2 notifies the terminal device
100-2 of the frequency group and the measurement gap (S453).
[0300] Then, the terminal device 100-2 (the measurement unit 153)
performs measurement of the frequency group (S455). Specifically,
the measurement unit 153 performs measurement of the first
frequency band based on a DRS transmitted in the first frequency
band within a first period included in the measurement gap. In
addition, the measurement unit 153 performs measurement of the
second frequency band based on a reference signal transmitted in
the second frequency band within a second period included in the
measurement gap.
[0301] Then, the terminal device 100-2 (the reporting unit 155)
reports a result of measurement of the frequency band to the base
station 200-2 (S457).
(Frequency Group Decision Process)
(a) First Example
[0302] FIG. 29 is a sequence diagram illustrating a first example
of a schematic flow of a frequency group decision process according
to the second embodiment.
[0303] The processing unit 330 determines whether two or more
frequency bands in which a DRS is transmitted exist (S431). When
two or more frequency bands do not exist (NO in S431), the process
ends.
[0304] When two or more frequency bands in which a DRS is
transmitted exist (YES in S431), the information acquiring unit 331
acquires information about the two or more frequency bands in which
a DRS is transmitted (S433).
[0305] Then, the control unit 333 decides a frequency group
including at least a first frequency band and a second frequency
band among the two or more frequency bands (S435).
[0306] In addition, the control unit 333 decides a measurement gap
(S437).
[0307] Then, the control unit 333 controls a transmission period in
which a DRS is transmitted in the first frequency band such that
the DRS is transmitted in the first frequency band within at least
a first period included in the measurement gap (S438). For example,
the control unit 333 instructs a base station that transmits a DRS
in the first frequency band to transmit the DRS during the
measurement gap
[0308] In addition, the control unit 333 controls a transmission
period in which a DRS is transmitted in the second frequency band
such that the DRS is transmitted in the second frequency band
within at least a second period included in the measurement gap
(S439). For example, the control unit 333 instructs a base station
that transmits a DRS in the second frequency band to transmit the
DRS during the measurement gap. Then, the process ends.
(b) Second Example
[0309] FIG. 30 is a sequence diagram illustrating a second example
of a schematic flow of a frequency group decision process according
to the second embodiment.
[0310] The processing unit 330 determines whether two or more
frequency bands in which a DRS is transmitted exist (S441). When
two or more frequency bands do not exist (NO in S441), the process
ends.
[0311] When two or more frequency bands in which a DRS is
transmitted exist (YES in S441), the information acquiring unit 331
acquires information about the two or more frequency bands in which
a DRS is transmitted (S443). The information about the two or more
frequency bands includes information indicating a transmission
period in which a DRS is transmitted in each of the two or more
frequency bands.
[0312] Then, the control unit 333 determines whether at least two
frequency bands whose transmission periods of a DRS are the same
(or similar) are included in the two or more frequency bands (S445)
When the at least two frequency bands are not included (NO in
S445), the process ends
[0313] When the at least two frequency bands are included (YES in
S445), the control unit 333 decides a frequency group including at
least two frequency bands (at least a first frequency band and a
second frequency band) whose transmission periods of a DRS are the
same (or similar) among the two or more frequency bands (S447).
[0314] In addition, the control unit 333 decides a measurement gap
that overlaps the transmission period of the DRS (S449). Then, the
process ends.
4.5. First Modification Example
[0315] Next, a first modification example of the second embodiment
will be described.
[0316] In the first modification example of the second embodiment,
the base station 200-2 decides the frequency group (and the
measurement gap) instead of the control entity 300-2. Then, the
base station 200-2 notifies the terminal device 100-2 of the
frequency group (and the measurement gap) it decided.
[0317] For example, in the first modification example of the second
embodiment, the processing unit 260 of the base station 200-2
further includes the information acquiring unit 331 and the control
unit 333.
4.6. Second Modification Example
[0318] Next, a second modification example of the second embodiment
will be described.
[0319] In the first modification example of the second embodiment,
the terminal device 100-2 decides the frequency group (and the
measurement gap) instead of the control entity 300-2. Then, the
base station 200-2 performs measurement of the frequency group it
decided.
(Terminal Device 100-2: Processing Unit 150)
[0320] In the second modification example of the second embodiment,
the processing unit 150 decides a frequency group including at
least a first frequency band and a second frequency band among two
or more frequency bands in which a DRS is transmitted. In addition,
for example, the processing unit 150 decides a measurement gap that
is used for measurement of the frequency group.
[0321] As a specific example, the base station 200-2 notifies the
terminal device 100-2 of two or more frequency bands in which a DRS
is transmitted. For example, the base station 200-2 informs of the
inter-frequency NCL (SIB5) including information indicating whether
a DRS is transmitted for each frequency band and a transmission
period of a DRS. For example, the processing unit 150 decides at
least two frequency bands whose transmission periods of a DRS are
the same (or similar) among the two or more frequency bands as a
frequency group based on information about the transmission period.
The processing unit 150 decides frequency bands whose number is
equal to or less than a predetermined maximum number as a frequency
group. In addition, the processing unit 150 decides a measurement
gap that overlaps the same transmission period.
(Terminal Device 100-2: Information Acquiring Unit 151)
[0322] As described above, the information acquiring unit 151
acquires information indicating the frequency group including the
first frequency band and the second frequency band. In addition,
the information acquiring unit 151 acquires information indicating
the measurement gap.
[0323] In the second modification example of the second embodiment,
for example, as described above, the processing unit 150 decides
the frequency group and the measurement gap. Then, the information
acquiring unit 151 acquires information indicating the decided
frequency group and information indicating the decided measurement
gap.
5. Third Embodiment
[0324] Next, a third embodiment of the present disclosure will be
described with reference to FIG. 31 to FIG. 40
[0325] The terminal device 100-3 according to the third embodiment
performs measurement of a first frequency band based on a discovery
reference signal transmitted in the first frequency band within a
first period included in a measurement gap, and performs
measurement of a second frequency band based on a reference signal
transmitted in the second frequency band within a second period
included in the measurement gap. Specifically, in the third
embodiment, the measurement gap is an extended measurement gap.
Accordingly, for example, it is possible to improve measurement
performed by the terminal device 100-3.
5.1. Configuration of Terminal Device
[0326] First, examples of configurations of the terminal device
100-3 according to the third embodiment will be described with
reference to FIG. 31 to FIG. 35. FIG. 31 is a block diagram
illustrating an example of a configuration of the terminal device
100-3 according to the third embodiment. As illustrated in FIG. 31,
the terminal device 100-3 includes the antenna unit 110, the
wireless communication unit 120, the storage unit 130 and a
processing unit 160.
[0327] There is no difference in descriptions of the antenna unit
110, the wireless communication unit 120 and the storage unit 130
between the first embodiment and the third embodiment except for
different reference numerals Therefore, redundant descriptions will
be omitted here, and only the processing unit 160 will be
described.
(Processing Unit 160)
[0328] The processing unit 160 provides various functions of the
terminal device 100-3. The processing unit 160 includes an
information acquiring unit 161, a measurement unit 163 and a
reporting unit 165. The processing unit 160 may further include a
component other than these components. That is, the processing unit
160 may also perform an operation other than operations of these
components.
(Information Acquiring Unit 161)
[0329] The information acquiring unit 161 acquires information
indicating a first frequency band in which a DRS is transmitted
within at least a first period included in a measurement gap. For
example, the information acquiring unit 161 acquires information
indicating a frequency group including the first frequency band and
a second frequency band. Specifically, in the third embodiment, the
measurement gap is an extended measurement gap. In addition, for
example, the second frequency band is a frequency band in which a
reference signal is transmitted within at least a second period
included in the measurement gap (that is, the extended measurement
gap).
[0330] In addition, the information acquiring unit 161 acquires
information indicating the measurement gap. The measurement gap
(that is, the extended measurement gap) will be described below in
detail.
[0331] For example, a base station 200-3 notifies the terminal
device 100-3 of the first frequency band (or the frequency group)
and the measurement gap. As a specific example, the base station
200-3 transmits information indicating the first frequency band (or
the frequency group) and information indicating the measurement gap
to the terminal device 100-3. As an example, the base station 200-3
transmits an RRC connection reconfiguration message including a
measurement configuration including the information indicating the
first frequency band (or the frequency group) and the information
indicating the measurement gap to the terminal device 100-3. Then,
the information acquiring unit 161 acquires the information
indicating the first frequency band (or the frequency group) and
the information indicating the measurement gap.
(Measurement Unit 163)
[0332] The measurement unit 163 performs measurement of a frequency
band.
[0333] In the third embodiment, the measurement unit 163 performs
measurement of a first frequency band based on a DRS transmitted in
the first frequency band within a first period included in a
measurement gap. In addition, the measurement unit 163 performs
measurement of a second frequency band based on a reference signal
transmitted in the second frequency band within a second period
included in the measurement gap. Accordingly, for example, it is
possible to improve measurement performed by the terminal device
100-3.
(a) Frequency Band
[0334] Component Carrier (CC)
[0335] For example, each of the first frequency band and the second
frequency band is a component carrier (CC) of carrier
aggregation.
[0336] Frequency Band of Small Cell
[0337] For example, each of the first frequency band and the second
frequency band is a frequency band that is used by a base station
of a small cell.
[0338] Frequency Band that is not Used
[0339] For example, each of the first frequency band and the second
frequency band is a frequency band that is not used by the terminal
device 100-3.
[0340] In view of the above points, for example, each of the first
frequency band and the second frequency band is a CC that is used
by a base station of a small cell, and the CC is not used by the
terminal device 100-3.
(b) Measurement
[0341] The measurement of the first frequency band and the
measurement of the second frequency band are RRM measurement, for
example, measurement of reception power or reception quality. As a
specific example, the measurement of the first frequency band and
the measurement of the second frequency band are measurement of
RSRP or RSRQ.
[0342] In addition, for example, measurement is performed in units
of a combination of a frequency band and a cell (a base station).
For example, the measurement of the first frequency band is
performed for each cell in which the first frequency band is used
(that is, a base station that uses the first frequency band). In
addition, for example, the measurement of the second frequency band
is performed for each cell in which the second frequency band is
used (that is, a base station that uses the second frequency
band).
(c) Reference Signal
[0343] For example, the reference signal transmitted in the second
frequency band is a CRS. That is, the measurement unit 163 performs
measurement of the first frequency band in which a DRS is
transmitted and measurement of the second frequency band in which a
CRS is transmitted using the measurement gap.
[0344] Alternatively, the reference signal transmitted in the
second frequency band may be a DRS.
[0345] The DRS is a reference signal that is transmitted by a base
station of the small cell in the off state. The DRS may also be
referred to as a discovery signal (DR).
(d) Measurement Gap
[0346] Specifically, in the third embodiment, the measurement gap
is an extended measurement gap. More specifically, for example, the
extended measurement gap is a period longer than 6 milliseconds
(ms). For example, a general measurement gap (that is, a
measurement gap that is not extended) is a period having a length
of 6 ms.
[0347] Further, for example, the first period is a period shorter
than the second period. As described above, for example, since the
reference signal transmitted in the second frequency band within
the second period is a CRS, a shorter period is used for
measurement of the first frequency band based on a DRS than
measurement of the second frequency band based on a CRS.
(e) Specific Example of Measurement
[0348] Hereinafter, examples of measurement according to the third
embodiment will be described with reference to FIG. 32 and FIG.
33.
[0349] FIG. 32 is an explanatory diagram for describing a first
example of measurement according to the third embodiment. Referring
to FIG. 32, an extended measurement gap having a length of 8
subframes is shown. In this example, the measurement unit 163
performs measurement of a CC2 based on a CRS transmitted in the CC2
(a second frequency band) within a period (a second period) from a
1st subframe to a 6th subframe within the extended measurement gap.
In addition, the measurement unit 163 performs measurement of a CC1
based on a DRS transmitted in the CC1 (a first frequency band)
within a period (a first period) including a 7th subframe and an
8th subframe within the extended measurement gap.
[0350] FIG. 33 is an explanatory diagram for describing a second
example of measurement according to the third embodiment. Referring
to FIG. 33, an extended measurement gap having a length of 8
subframes is shown. In this example, the measurement unit 163
performs measurement of a CC1 based on a DRS transmitted in the CC1
(a first frequency band) within a period (a first period) including
a 1st subframe and a 2nd subframe within the extended measurement
gap. In addition, the measurement unit 163 performs measurement of
a CC2 based on a CRS transmitted in the CC2 (a second frequency
band) within a period (a second period) from a 3rd subframe to an
8th subframe within the extended measurement gap.
[0351] When measurement of the first frequency band and measurement
of the second frequency band are collectively performed using the
extended measurement gap, for example, it is possible to perform
measurement of the first frequency band and measurement of the
second frequency band using fewer measurement gaps. For example,
the terminal device 100-3 can perform measurement of the first
frequency band based on a DRS while performing measurement of the
second frequency band based on a CRS. Alternatively, the terminal
device 100-3 can perform measurement of the second frequency band
based on a CRS while performing measurement of the first frequency
band based on a DRS Therefore, measurement based on the DRS (that
is, inter-frequency measurement of a frequency band that is used by
a base station of a small cell) may be efficiently performed. As a
specific example, measurement based on the DRS may be performed
more quickly.
[0352] In addition, as described above, when measurement based on a
DRS is performed using a short period, the extended measurement gap
may be shortened. That is, a period in which transmission of a
signal from the terminal device 100-3 and transmission of a signal
to the terminal device 100-3 are not continuous may be
shortened.
(f) Measurement of Additional Frequency Band
[0353] The measurement gap (that is, the extended measurement gap)
may include an additional period. The measurement unit 163 may
perform measurement of an additional frequency band based on a DRS
transmitted in the additional frequency band within the additional
period. Hereinafter, this will be described with reference to a
specific example of FIG. 34.
[0354] FIG. 34 is an explanatory diagram for describing a third
example of measurement according to the third embodiment. Referring
to FIG. 34, an extended measurement gap having a length of 10
subframes is shown. In this example, the measurement unit 163
performs measurement of a CC2 based on a CRS transmitted in the CC2
(a second frequency band) within a period (a second period) from a
1st subframe to a 6th subframe within the extended measurement gap.
In addition, the measurement unit 163 performs measurement of a CC1
based on a DRS transmitted in the CC1 (a first frequency band)
within a period (a first period) including a 7th subframe and an
8th subframe within the extended measurement gap. Further, the
measurement unit 163 performs measurement of a CC3 based on a DRS
transmitted in the CC3 (an additional frequency band) within a
period (an additional period) including a 9th subframe and a 10th
subframe within the extended measurement gap.
[0355] Accordingly, measurement based on a DRS (that is,
inter-frequency measurement) may be further efficiently
performed.
[0356] While an example in which the measurement gap (that is, the
extended measurement gap) includes one additional period and the
measurement unit 163 performs measurement of one additional
frequency band has been described, it should be understood that the
third embodiment is not limited thereto. The measurement gap may
include two or more additional periods, and the measurement unit
163 may perform measurement of two or more additional frequency
bands.
(g) Measurement Based on CRS and DRS
[0357] The measurement unit 163 may perform the measurement of the
first frequency band that is used by the same base station based on
a DRS and a CRS transmitted by the same base station in the first
frequency band within the first period. Additionally or
alternatively, the measurement unit 163 may perform the measurement
of the second frequency band that is used by the same base station
based on a DRS and a CRS transmitted by the same base station in
the second frequency band within the second period. In this case,
the first period may be a period shorter than 6 milliseconds.
[0358] As a specific example, a base station of a small cell in the
on state transmits both a DRS and a CRS in the second frequency
band. In this case, the measurement unit 163 may perform
measurement of the second frequency band that is used by the base
station based on the DRS and the CRS transmitted by the base
station in the second frequency band within the second period.
Hereinafter, hereinafter, this will be described with reference to
a specific example of FIG. 35.
[0359] FIG. 35 is an explanatory diagram for describing a fourth
example of measurement according to the third embodiment. Referring
to FIG. 35, an extended measurement gap having a length of 8
subframes is shown. In this example, the measurement unit 163
performs measurement of a CC2 based on a DRS and a CRS transmitted
by the same base station using the CC2 (a second frequency band)
within a period (a second period) from a 1st subframe to a 4th
subframe within the extended measurement gap. In addition, the
measurement unit 163 performs measurement of a CC1 based on a DRS
transmitted in the CC1 (a first frequency band) within a period (a
first period) including a 5th subframe and a 6th subframe within
the measurement gap. Further, the measurement unit 163 performs
measurement of a CC3 based on a DRS transmitted in the CC3 (an
additional frequency band) within a period (an additional period)
including a 7th subframe and an 8th subframe within the extended
measurement gap.
[0360] Accordingly, for example, measurement of the first frequency
band or the second frequency band (that is, inter-frequency
measurement) is performed based on more reference signals.
Therefore, the measurement of the first frequency band or the
second frequency band used by the base station may be performed
using a shorter period than when it is performed based on only a
CRS. Therefore, the extended measurement gap may be shortened.
(h) Priority
[0361] For example, the measurement unit 163 performs measurement
of a frequency group and measurement of one or more other frequency
bands or measurement of one or more other frequency groups based on
a priority of the frequency group including the first frequency
band and the second frequency band and a priority of the one or
more other frequency bands or a priority of the one or more other
frequency groups.
[0362] As a specific example, a frequency group or a frequency band
having a higher priority is sequentially selected from among the
frequency group including the first frequency band and the second
frequency band, the one or more other frequency bands and the one
or more other frequency groups. Then, the measurement unit 163
performs measurement of the selected frequency group or frequency
band.
[0363] As an example, the priority of the frequency band is a
priority included in an inter-frequency NCL contained in the SIB5.
As another example, the priority of the frequency band may be a
priority that is decided by the terminal device 100-3.
[0364] The priority of the frequency group (and/or a priority of
each of the one or more other frequency groups) may be decided in
consideration of power consumption and/or a communication request
of the terminal device 100-3. As an example, when suppression of
power consumption is requested, the priority of the frequency group
may be higher. This is because, when the priority of the frequency
group is high, measurement of more frequency bands using a
measurement gap is performed. As another example, when high
throughput is requested, the priority of the frequency group may be
lower. This is because, when the priority of the frequency group is
low, measurement of a frequency band that is used by a base station
of a cell in the on state is preferentially performed, and, as a
result, a handover is preferentially performed without a transition
time.
[0365] Measurement in Consideration of Transmission Period of
DRS
[0366] For example, the measurement unit 163 performs the
measurement of the frequency group, the measurement of the one or
more other frequency bands or the measurement of the one or more
other frequency groups in consideration of a transmission period in
which a DRS is transmitted in the first frequency band. As a
specific example, the measurement unit 163 performs measurement of
another frequency band or another frequency group whose priority is
lower than the frequency group before the measurement of the
frequency group outside of the transmission period.
[0367] Accordingly, for example, measurement may be performed more
smoothly without wasting the measurement gap
(Reporting Unit 165)
[0368] The reporting unit 165 reports a result of measurement of
the frequency band to the base station 200-3
[0369] For example, the reporting unit 165 reports a result of
measurement of the frequency band to the base station 200-3. In
addition, for example, the reporting unit 165 reports a result of
measurement of the second frequency band to the base station 200-3.
In addition, the frequency group may include an additional
frequency band, and the reporting unit 165 may report a result of
measurement of the additional frequency band to the base station
200-3.
5.2. Configuration of Base Station
[0370] Next, an example of a configuration of the base station
200-3 according to the third embodiment will be described with
reference to FIG. 36. FIG. 36 is a block diagram illustrating an
example of a configuration of the base station 200-3 according to
the third embodiment. Referring to FIG. 36, the base station 200-3
includes an antenna unit 210, a wireless communication unit 220, a
network communication unit 230, a storage unit 240, and a
processing unit 270.
[0371] There is no difference in descriptions of the antenna unit
210, the wireless communication unit 220, the network communication
unit 230 and the storage unit 240 between the first embodiment and
the third embodiment except for different reference numerals.
Therefore, redundant descriptions will be omitted here, and only
the processing unit 270 will be described.
(Processing Unit 270)
[0372] The processing unit 270 provides various functions of the
base station 200-3. The processing unit 270 includes an information
acquiring unit 271 and a control unit 273. The processing unit 270
may further include any other component in addition to the
above-mentioned components. In other words, the processing unit 270
may also perform an operation other than operations of the
above-mentioned components.
(Information Acquiring Unit 271)
(a) Frequency Group
[0373] The information acquiring unit 271 acquires information
indicating a first frequency band in which a DRS is transmitted
within at least a first period included in a measurement gap.
[0374] Specifically, in the third embodiment, the measurement gap
is an extended measurement gap. For example, the measurement gap
further includes a second period in which a reference signal is
transmitted in a second frequency band. More specifically, for
example, the measurement gap includes a second period in which a
CRS is transmitted in the second frequency band.
[0375] For example, the information acquiring unit 271 acquires
information indicating a frequency group including the first
frequency band and the second frequency band. The second frequency
band is a frequency band in which a DRS is transmitted within at
least a second period included in the measurement gap.
[0376] More specifically, for example, a control entity 300-3
decides the frequency group and notifies the base station 200-3 of
the frequency group. Then, the information indicating the frequency
group is stored in the storage unit 240. The information acquiring
unit 271 acquires the information indicating the frequency group at
any time thereafter.
(b) Measurement Gap
[0377] Further, for example, the information acquiring unit 271
acquires information indicating the measurement gap. As described
above, the measurement gap is an extended measurement gap.
[0378] More specifically, for example, the control entity 300-3
decides an extended measurement gap and notifies the base station
200-3 of the extended measurement gap. Then, the information
indicating the extended measurement gap is stored in the storage
unit 240. The information acquiring unit 271 acquires the
information indicating the extended measurement gap at any time
thereafter.
[0379] Alternatively, the measurement gap is decided by a device
other than the control entity 300-3, and the base station 200-3 may
be notified thereof. Alternatively, the measurement gap is decided
by the base station 200-3 and may be stored in the storage unit
240.
(Control Unit 263)
(a) Notification of First Frequency Band and Measurement Gap
[0380] The control unit 273 notifies the terminal device 100-3 of
the first frequency band and the measurement gap. Specifically, in
the third embodiment, the measurement gap is an extended
measurement gap.
[0381] For example, the control unit 273 notifies the terminal
device 100-3 of the frequency group including the first frequency
band and the second frequency band and the measurement gap.
[0382] As a specific example, the control unit 273 transmits
information indicating the frequency group and information
indicating the measurement gap (that is, the extended measurement
gap) to the terminal device 100-3 through the antenna unit 210 and
the wireless communication unit 220. As an example, the control
unit 273 transmits an RRC connection reconfiguration message
including a measurement configuration including the information
indicating the frequency group and the information indicating the
measurement gap to the terminal device 100-3 through the antenna
unit 210 and the wireless communication unit 220.
(b) Priority Notification
[0383] For example, the control unit 273 notifies the terminal
device 100-3 of a priority of the frequency group and a priority of
one or more other frequency bands or a priority of one or more
other frequency groups.
[0384] As a specific example, the control unit 273 transmits
information indicating the priority of the frequency group and the
priority of one or more other frequency bands or the priority of
one or more other frequency groups to the terminal device 100-3
through the antenna unit 210 and the wireless communication unit
220. As an example, the information is included in the
inter-frequency NCL within the SIB5 and the control unit 273
informs the terminal device 100-3 of the SIB5 including the
inter-frequency NCL through the antenna unit 210 and the wireless
communication unit 220.
5.3. Configuration of Control Entity
[0385] First, an example of a configuration of the control entity
300-3 according to the third embodiment will be described with
reference to FIG. 37. FIG. 37 is a block diagram illustrating an
example of a configuration of the control entity 300-3 according to
the third embodiment. Referring to FIG. 37, the control entity
300-3 includes a communication unit 310, a storage unit 320, and a
processing unit 340.
[0386] There is no difference in descriptions of the communication
unit 310 and the storage unit 320 between the second embodiment and
the third embodiment except for different reference numerals.
Therefore, redundant descriptions will be omitted here, and only
the processing unit 340 will be described.
(Processing Unit 340)
[0387] The processing unit 340 provides various functions of the
control entity 300-3. The processing unit 340 includes an
information acquiring unit 341 and a control unit 343. The
processing unit 340 may further include any other component in
addition to the above-mentioned components. In other words, the
processing unit 340 may also perform an operation other than
operations of the above-mentioned components.
(Information Acquiring Unit 341)
[0388] The information acquiring unit 341 acquires information
about a first frequency band in which a DRS is transmitted.
[0389] The first frequency band is a frequency band that is used by
a base station of a small cell. When a base station of a small cell
in the off state transmits a DRS and a base station of a small cell
in the on state does not transmit a DRS, the first frequency band
is a frequency band that is used by the base station of the small
cell in the off state. Conversely, when a base station of a small
cell transmits a DRS regardless of an on/off state, the first
frequency band is a frequency band that is used by the base station
of the small cell.
(Control Unit 343)
(a) Decision of Extended Measurement Gap
[0390] The control unit 343 decides an extended measurement gap
including at least a part of a transmission period in which a DRS
is transmitted in the first frequency band.
(a-1) First Method
[0391] For example, as a first method, the control unit 343
controls the transmission period such that at least a part of the
transmission period is included in the extended measurement
gap.
[0392] More specifically, for example, the control unit 343 decides
an extended measurement gap. Then, the control unit 343 instructs a
base station that transmits a DRS in the first frequency band to
transmit a DRS during the extended measurement gap.
[0393] Accordingly, for example, it is possible to more reliably
perform measurement of the first frequency band using the extended
measurement gap
(a-2) Second Method
[0394] As a second method, the information about the first
frequency band (that is, information acquired by the information
acquiring unit 341) may include information indicating the
transmission period. Then, the control unit 343 may decide the
extended measurement gap based on the transmission period (that is,
a period in which a DRS is transmitted in the first frequency
band).
[0395] As an example, the transmission period and the extended
measurement gap are periods having the same length, and the control
unit 343 decides the extended measurement gap such that the
extended measurement gap matches the transmission period. As
another example, the transmission period may be a period longer
than the extended measurement gap, and the control unit 343 may
decide the extended measurement gap such that the extended
measurement gap is included in the transmission period. As still
another example, the transmission period may be a period shorter
than the extended measurement gap, and the control unit 343 may
decide the extended measurement gap such that the extended
measurement gap includes the entire transmission period.
[0396] Accordingly, for example, it is possible to perform
measurement of each of the first frequency band and the second
frequency band using the extended measurement gap without the
control entity 300-3 instructing a base station.
(b) Decision of Frequency Group
[0397] For example, the control unit 343 decides a frequency group
including at least the first frequency band and the second
frequency band
[0398] The first frequency band is a frequency band in which a DRS
is transmitted within at least a first period included in the
measurement gap. In addition, the second frequency band is a
frequency band in which a reference signal is transmitted within at
least a second period included in the measurement gap. For example,
the reference signal is a CRS.
[0399] For example, the control unit 343 selects any frequency band
in which a CRS is transmitted (for example, a frequency band used
by a base station of a macro cell or a frequency band used by a
base station of a small in the on state) as the second frequency
band. Then, the control unit 343 decides a frequency group
including the first frequency band and the second frequency
band.
[0400] Alternatively, the reference signal transmitted in the
second frequency band may be a DRS. In this case, the control unit
343 may decide the frequency group in the same manner as in the
control unit 333 according to the second embodiment.
(c) Provide Notification to Base Station 200-3
[0401] For example, the control unit 343 notifies the base station
200-3 of the extended measurement gap.
[0402] For example, the control unit 343 notifies the base station
200-3 of the first frequency band. For example, the control unit
343 notifies the base station 200-3 of the frequency group
including the first frequency band and the second frequency
band.
[0403] As a specific example, the control unit 343 transmits a
message including information indicating the frequency group and
information indicating the extended measurement gap to the base
station 200-3 through the communication unit 310.
5.4. Process Flow
[0404] Next, examples of processes according to the third
embodiment will be described with reference to FIG. 38 to FIG.
40.
(Overall Process Flow)
[0405] FIG. 38 is a sequence diagram illustrating an example of a
schematic flow of a process according to the third embodiment.
[0406] The control entity 300-3 performs an extended measurement
gap decision process (S470) That is, the control unit 343 decides
an extended measurement gap including at least a part of a
transmission period in which a DRS is transmitted in a first
frequency band.
[0407] In addition, the control entity 300-3 decides a frequency
group including at least the first frequency band and a second
frequency band (S491).
[0408] Then, the control entity 300-3 notifies the base station
200-3 of the frequency group and the extended measurement gap
(S493)
[0409] Further, the base station 200-3 notifies the terminal device
100-3 of the frequency group and the extended measurement gap
(S495).
[0410] Then, the terminal device 100-3 (the measurement unit 163)
performs measurement of the frequency group (S497). As a specific
example, the measurement unit 163 performs measurement of the first
frequency band based on a DRS transmitted in the first frequency
band within a first period included in the extended measurement
gap. In addition, for example, the measurement unit 163 performs
measurement of the second frequency band based on a reference
signal (for example, a CRS) transmitted in the second frequency
band within a second period included in the extended measurement
gap.
[0411] Then, the terminal device 100-3 (the reporting unit 165)
reports a result of measurement of the frequency band to the base
station 200-3 (S499).
(Extended Measurement Gap Decision Process)
(a) First Example
[0412] FIG. 39 is a sequence diagram illustrating a first example
of a schematic flow of an extended measurement gap decision process
according to the third embodiment.
[0413] The information acquiring unit 341 acquires information
about a first frequency band in which a DRS is transmitted
(S471).
[0414] Then, the control unit 343 decides an extended measurement
gap (S473).
[0415] Further, the control unit 343 controls a transmission period
in which a DRS is transmitted in the first frequency band such that
the DRS is transmitted in the first frequency band within at least
a first period included in the extended measurement gap (S475). For
example, the control unit 343 instructs a base station that
transmits a DRS in the first frequency band to transmit the DRS
during the extended measurement gap. Then, the process ends.
(b) Second Example
[0416] FIG. 40 is a sequence diagram illustrating a second example
of a schematic flow of an extended measurement gap decision process
according to the third embodiment.
[0417] The information acquiring unit 341 acquires information
about a first frequency band in which a DRS is transmitted (S481).
The information includes information indicating a transmission
period in which a DRS is transmitted in the first frequency
band.
[0418] Then, the control unit 343 decides an extended measurement
gap based on the transmission period (that is, a period in which a
DRS is transmitted in the first frequency band) (S483). Then, the
process ends.
5.5. First Modification Example
[0419] Next, a first modification example of the third embodiment
will be described.
[0420] In the first modification example of the third embodiment,
the base station 200-3 decides the extended measurement gap instead
of the control entity 300-3. In addition, for example, the base
station 200-3 decides the frequency group. Then, the base station
200-3 notifies the terminal device 100-3 of the extended
measurement gap and the frequency group it decided.
[0421] For example, in the first modification example of the third
embodiment, the processing unit 270 of the base station 200-3
further includes, for example, the information acquiring unit 341
and the control unit 343.
5.6. Second Modification Example
[0422] Next, a second modification example of the third embodiment
will be described.
[0423] In the second modification example of the third embodiment,
the terminal device 100-3 decides the extended measurement gap
instead of the control entity 300-3. In addition, for example, the
terminal device 100-3 decides the frequency group. Then, the base
station 200-3 performs measurement of the frequency group it
decided by using the extended measurement gap it decided.
(Terminal Device 100-3: Processing Unit 160)
[0424] In the second modification example of the third embodiment,
the processing unit 160 decides the extended measurement gap. In
addition, for example, the processing unit 160 decides a frequency
group including at least a first frequency band in which a DRS is
transmitted and a second frequency band in which a reference signal
(for example, a CRS) is transmitted.
[0425] As a specific example, the base station 200-3 notifies the
terminal device 100-3 of information about a first frequency band
in which a DRS is transmitted. For example, the base station 200-3
informs of the inter-frequency NCL (SIB5) including information
indicating whether a DRS is transmitted for each frequency band and
a transmission period of a DRS. Then, the processing unit 160
decides an extended measurement gap including at least a part of
the transmission period in which a DRS is transmitted in the first
frequency band. In addition, the processing unit 160 decides a
frequency group including at least the first frequency band and the
second frequency band. The processing unit 160 decides frequency
bands whose number is equal to or less than a predetermined maximum
number as a frequency group.
(Terminal Device 100-3: Information Acquiring Unit 161)
[0426] As described above, the information acquiring unit 161
acquires information indicating the first frequency band (or the
frequency group). In addition, as described above, the information
acquiring unit 161 acquires information indicating the extended
measurement gap.
[0427] For example, as described above, the processing unit 160
decides the frequency group and the extended measurement gap. Then,
the information acquiring unit 161 acquires information indicating
the decided frequency group and information indicating the decided
extended measurement gap.
6. Fourth Embodiment
[0428] Next, a fourth embodiment of the present disclosure will be
described with reference to FIG. 41 to FIG. 43.
[0429] A terminal device 100-4 according to the fourth embodiment
performs first measurement of each of a plurality of frequency
bands and second measurement of each of one or more frequency bands
that are a part of the plurality of frequency bands. The first
measurement is measurement that is performed based on a reference
signal transmitted within a period having a first length. The
second measurement is measurement that is performed based on a
reference signal transmitted within a period having a second length
that is greater than the first length. That is, in the fourth
embodiment, the terminal device 100-4 performs rough measurement of
more frequency bands and performs more accurate measurement of
fewer frequency bands that are a part of the more frequency bands.
Accordingly, for example, it is possible to improve measurement
performed by the terminal device 100-4.
<6.1. Configuration of Terminal Device>
[0430] First, an example of a configuration of the terminal device
100-4 according to the fourth embodiment will be described with
reference to FIG. 41 and FIG. 42. FIG. 41 is a block diagram
illustrating an example of a configuration of the terminal device
100-4 according to the fourth embodiment. As illustrated in FIG.
41, the terminal device 100-4 includes the antenna unit 110, the
wireless communication unit 120, the storage unit 130 and a
processing unit 170.
[0431] There is no difference in descriptions of the antenna unit
110, the wireless communication unit 120 and the storage unit 130
between the first embodiment and the fourth embodiment except for
different reference numerals. Therefore, redundant descriptions
will be omitted here, and only the processing unit 170 will be
described.
(Processing Unit 170)
[0432] The processing unit 170 provides various functions of the
terminal device 100-4. The processing unit 170 includes an
information acquiring unit 171, a measurement unit 173 and a
reporting unit 175. The processing unit 170 may further include a
component other than these components. That is, the processing unit
170 may also perform an operation other than operations of these
components.
(Information Acquiring Unit 171)
[0433] The information acquiring unit 171 acquires information
about a frequency band
[0434] For example, the information acquiring unit 171 acquires a
neighbor cell list. For example, the information acquiring unit 171
acquires an intra-frequency NCL and an inter-frequency NCL For
example, a base station 200-4 informs the information acquiring
unit 171 of an intra-frequency NCL within an SIB4, and the
information acquiring unit 171 acquires the intra-frequency NCL. In
addition, for example, the base station 200-4 informs the
information acquiring unit 171 of an inter-frequency NCL within an
SIB5 and the information acquiring unit 171 acquires the
inter-frequency NCL.
[0435] For example, the information acquiring unit 171 acquires a
measurement configuration of a frequency band. For example, the
base station 200-4 transmits an RRC connection reconfiguration
message including a measurement configuration to the terminal
device 100-4, and the information acquiring unit 171 acquires the
measurement configuration. The measurement configuration includes
information such as measurement objects, reporting configurations,
measurement IDs and measurement gaps.
(Measurement Unit 173)
[0436] The measurement unit 173 performs measurement of a frequency
band.
[0437] In the fourth embodiment, the measurement unit 173 performs
first measurement of each of a plurality of frequency bands and
second measurement of each of one or more frequency bands that are
a part of the plurality of frequency bands. The first measurement
is measurement that is performed based on a reference signal
transmitted within a period having a first length. The second
measurement is measurement that is performed based on a reference
signal transmitted within a period having a second length that is
greater than the first length. That is, the measurement unit 173
performs rough measurement of more frequency bands (that is, the
plurality of frequency bands) and performs more accurate
measurement of fewer frequency bands (that is, the one or more
frequency bands) that are a part of the more frequency bands.
Accordingly, for example, it is possible to improve measurement
performed by the terminal device 100-4. For example, measurement of
the frequency band may be performed more efficiently.
(a) First Measurement of Each of Plurality of Frequency Bands
[0438] (a-1) Plurality of Frequency Bands
[0439] Component Carrier (CC)
[0440] For example, each of the plurality of frequency bands is a
component carrier (CC) of carrier aggregation.
[0441] Frequency Band of Small Cell
[0442] For example, each of the plurality of frequency bands is a
frequency band that is used by a base station of a small cell.
Accordingly, for example, measurement of the frequency band used in
the small cell may be performed more efficiently.
[0443] Frequency Band that is not Used
[0444] For example, each of the plurality of frequency bands is a
frequency band that is not used by the terminal device 100-4.
Accordingly, for example, inter-frequency measurement may be
performed more efficiently.
[0445] In view of the above points, for example, each of the
plurality of frequency bands is a CC that is used by a base station
of a small cell, and the CC is not used by the terminal device
100-4.
[0446] The plurality of frequency bands have been described above.
The fourth embodiment is not limited thereto. For example, the
plurality of frequency bands may include a frequency band that is
used by only a macro base station.
(a-2) First Measurement
[0447] As described above, the first measurement (that is, the
measurement of each of the plurality of frequency bands) is
measurement that is performed based on a reference signal
transmitted within a period having the first length.
[0448] Period Having First Length
[0449] For example, the period having the first length is a period
including a measurement gap of a first number. That is, the
measurement unit 173 performs measurement of each of the plurality
of frequency bands based on a reference signal transmitted within
the period including the measurement gap of the first number.
[0450] Reference Signal
[0451] For example, the reference signal is a CRS. Accordingly, for
example, measurement regarding a small cell in the on state may be
performed more efficiently. In addition, a measurement load
regarding a macro cell may be reduced.
[0452] Alternatively, the reference signal may be a DRS.
Accordingly, for example, measurement regarding a small cell in the
off state may be performed more efficiently.
[0453] RRM Measurement
[0454] The first measurement is RRM measurement, for example,
measurement of reception power or reception quality. As a specific
example, the first measurement is measurement of RSRP or RSRQ. In
addition, the first measurement is performed for each cell (that
is, a base station that uses each of the plurality of frequency
bands) in which each of the plurality of frequency bands is
used.
(b) Second Measurement of One or More Frequency Bands
[0455] (b-1) One or More Frequency Bands
[0456] For example, the one or more frequency bands are frequency
bands that are selected from among the plurality of frequency bands
based on a result of the first measurement of each of the plurality
of frequency bands.
[0457] More specifically, for example, the one or more frequency
bands are frequency bands the first measurement of which has a more
favorable result. As an example, for example, the one or more
frequency bands are frequency bands having higher RSRP (or RSRQ)
Hereinafter, this will be described with reference to a specific
example of FIG. 42.
[0458] FIG. 42 is an explanatory diagram for describing an example
of frequency bands that are targets of first measurement and second
measurement according to the fourth embodiment. Referring to FIG.
42, five CCs in one operating band are shown. For example, the
measurement unit 173 performs first measurement of each of the five
CCs. Then, two CCs having higher RSRP (or RSRQ) among the five CCs
are selected as targets of the second measurement, and the
measurement unit 173 performs the second measurement of the two
CCs.
[0459] Accordingly, for example, rough measurement of more
frequency bands is performed. Accurate measurement of fewer
frequency bands favorable for the terminal device 100-4 among the
more frequency bands is performed. That is, a frequency band
favorable for the terminal device 100-4 may be found quickly from
among the more frequency bands.
(b-2) Second Measurement
[0460] As described above, the first measurement is measurement
that is performed based on a reference signal transmitted within a
period having the first length. The second measurement is
measurement that is performed based on a reference signal
transmitted within a period having a second length that is greater
than the first length.
[0461] Period Having Second Length
[0462] As described above, for example, the period having the first
length is a period including a measurement gap of a first number.
Conversely, for example, the period having the second length is a
period including a measurement gap of a second number that is
greater than the first number. That is, the measurement unit 173
performs measurement of each of the one or more frequency bands
based on a reference signal transmitted within a period including
the measurement gap of the second number that is greater than the
first number.
[0463] Reference Signal
[0464] For example, the reference signal is a CRS. Alternatively,
the reference signal may be a DRS.
[0465] RRM Measurement
[0466] The second measurement is RRM measurement, for example,
measurement of reception power or reception quality. As a specific
example, the second measurement is measurement of RSRP or RSRQ. In
addition, the second measurement is performed for each cell in
which each of the one or more frequency bands is used (that is, a
base station that uses each of the one or more frequency
bands).
(Reporting Unit 175) The reporting unit 175 reports a result of
measurement of the frequency band to the base station 200-4.
[0467] For example, the reporting unit 175 reports a result of
measurement of each of the one or more frequency bands to the base
station 200-4.
6.2. Process Flow
[0468] Next, an example of a process according to the fourth
embodiment will be described with reference to FIG. 42. FIG. 42 is
a flowchart illustrating an example of a schematic flow of a
process according to the fourth embodiment.
[0469] The measurement unit 173 performs first measurement of each
of a plurality of frequency bands (S511).
[0470] Then, the processing unit 170 (for example, the measurement
unit 173) selects one or more frequency bands that are a part of
the plurality of frequency bands based on a result of the first
measurement of each of the plurality of frequency bands (S513)
[0471] Then, the measurement unit 173 performs second measurement
of each of the one or more frequency bands (S515). Then, the
process ends.
7. Application Examples
[0472] The technology according to the present disclosure is
applicable to a variety of products. The control entity 300 may be
implemented as any type of server such as tower servers, rack
servers, and blade servers. At least a part of components of the
control entity 300 may be implemented in a module (e.g. integrated
circuit module that includes a single die, or card or blade that is
inserted into a slot of a blade server) mounted on a server. In
addition, the control entity 300 may be implemented as any of
various base stations which will be described.
[0473] The base station 200 may also be implemented, for example,
as any type of evolved Node B (eNB) such as macro eNBs and small
eNBs. Small eNBs may cover smaller cells than the macrocells of
pico eNBs, micro eNBs, or home (femt) eNBs. Instead, the base
station 200 may be implemented as another type of base station such
as Nodes B or base transceiver stations (BTSs). The base station
200 may include the main apparatus (which is also referred to as
base station apparatus) that controls wireless communication and
one or more remote radio heads (RRHs) that are disposed at
different locations from that of the main apparatus. Further,
various types of terminals as will be discussed later may
temporarily or semi-persistently execute the base station function
to operate as the base station 200. Further, at least part of
components of the base station 200 may be implemented in a base
station device or a module for the base station device.
[0474] The terminal device 100 may be implemented as a mobile
terminal such as smartphones, tablet personal computers (PCs),
notebook PCs, portable game terminals, portable/dongle mobile
routers, and digital cameras, or an in-vehicle terminal such as car
navigation apparatuses. The terminal device 100 may also be
implemented as a terminal (which is also referred to as machine
type communication (MTC) terminal) that performs machine to machine
(M2M) communication. Furthermore, at least part of components of
the terminal device 100 may be implemented as a module (e.g.
integrated circuit module constituted with a single die) that is
mounted on these terminals.
7.1. Application Examples for Control Entity
[0475] FIG. 44 is a block diagram illustrating an example of a
schematic configuration of a server 700 to which the technology
according to the present disclosure may be applied. The server 700
includes a processor 701, a memory 702, a storage 703, a network
interface 704, and a bus 706.
[0476] The processor 701 may be, for example, a central processing
unit (CPU) or a digital signal processor (DSP), and controls
various functions of the server 700. The memory 702 includes a
random access memory (RAM) and a read only memory (ROM), and stores
a program executed by the processor 701 and data. The storage 703
can include a storage medium such as semiconductor memories and
hard disks.
[0477] The network interface 704 is a wired communication interface
for connecting the server 700 to a wired communication network 705.
The wired communication network 705 may be a core network such as
evolved packet cores (EPCs), or a packet data network (PDN) such as
the Internet.
[0478] The bus 706 connects the processor 701, the memory 702, the
storage 703, and the network interface 704 to each other. The bus
706 may include two or more buses each having different speed (e.g.
high speed bus and low speed bus).
[0479] In the server 700 illustrated in FIG. 44, one or more
components (the information acquiring unit 331 and/or the control
unit 333) included in the processing unit 330 described above with
reference to FIG. 27 may be mounted in the processor 701. As an
example, a program causing the processor to function as one or more
of the components above (that is, a program causing the processor
to perform the operation of one or more of the components above)
may be installed in the server 700, and the processor 701 may
execute the program. As another example, the server 700 may include
a module including the processor 701 and the memory 702, and one or
more of the components above may be mounted in the module. In this
case, the module may store the program causing the processor to
function as one or more of the components above in the memory 702,
and the program may be executed by the processor 701. As described
above, the server 700 or the module may be provided as an apparatus
including one or more of the components above, and the program
causing the processor to function as one or more of the components
above may be provided. A readable recording medium in which the
program is recorded may be provided. For these points, one or more
components included in the processing unit 340 described above with
reference to FIG. 37 (the information acquiring unit 341 and/or the
control unit 343) are the same as one or more of the components
above included in the processing unit 330.
7.2. Application Examples for Base Station
First Application Example
[0480] FIG. 45 is a block diagram illustrating a first example of a
schematic configuration of an eNB to which the technology according
to the present disclosure may be applied. An eNB 800 includes one
or more antennas 810 and a base station apparatus 820. Each antenna
810 and the base station apparatus 820 may be connected to each
other via an RF cable.
[0481] Each of the antennas 810 includes a single or a plurality of
antenna elements (e.g. a plurality of antenna elements constituting
a MIMO antenna) and is used for the base station apparatus 820 to
transmit and receive a wireless signal. The eNB 800 may include the
plurality of the antennas 810 as illustrated in FIG. 45, and the
plurality of antennas 810 may, for example, correspond to a
plurality of frequency bands used by the eNB 800. It should be
noted that while FIG. 45 illustrates an example in which the eNB
800 includes the plurality of antennas 810, the eNB 800 may include
the single antenna 810.
[0482] The base station apparatus 820 includes a controller 821, a
memory 822, a network interface 823, and a wireless communication
interface 825.
[0483] The controller 821 may be, for example, a CPU or a DSP, and
operates various functions of an upper layer of the base station
apparatus 820. For example, the controller 821 generates a data
packet from data in a signal processed by the wireless
communication interface 825, and transfers the generated packet via
the network interface 823. The controller 821 may generate a
bundled packet by bundling data from a plurality of base band
processors to transfer the generated bundled packet. The controller
821 may also have a logical function of performing control such as
radio resource control, radio bearer control, mobility management,
admission control, and scheduling. The control may be performed in
cooperation with a surrounding eNB or a core network. The memory
822 includes a RAM and a ROM, and stores a program executed by the
controller 821 and a variety of control data (such as, for example,
terminal list, transmission power data, and scheduling data).
[0484] The network interface 823 is a communication interface for
connecting the base station apparatus 820 to the core network 824.
The controller 821 may communicate with a core network node or
another eNB via the network interface 823. In this case, the
controller 821 may be mutually connected to the eNB 800 and a core
network node or another eNB through a logical interface (e.g. S1
interface or X2 interface). The network interface 823 may be a
wired communication interface or a wireless communication interface
for wireless backhaul. When the network interface 823 is a wireless
communication interface, the network interface 823 may use a higher
frequency band for wireless communication than a frequency band
used by the wireless communication interface 825.
[0485] The wireless communication interface 825 supports a cellular
communication system such as long term evolution (LTE) or
LTE-Advanced, and provides wireless connection to a terminal
located within the cell of the eNB 800 via the antenna 810. The
wireless communication interface 825 may typically include a base
band (BB) processor 826 and an RF circuit 827. The BB processor 826
may, for example, perform encoding/decoding,
modulation/demodulation, multiplexing/demultiplexing, and the like,
and performs a variety of signal processing on each layer (e.g. L1,
medium access control (MAC), radio link control (RLC), and packet
data convergence protocol (PDCP)). The BB processor 826 may have
part or all of the logical functions as discussed above instead of
the controller 821. The BB processor 826 may be a module including
a memory having a communication control program stored therein, a
processor to execute the program, and a related circuit, and the
function of the BB processor 826 may be changeable by updating the
program. The module may be a card or blade to be inserted into a
slot of the base station apparatus 820, or a chip mounted on the
card or the blade. Meanwhile, the RF circuit 827 may include a
mixer, a filter, an amplifier, and the like, and transmits and
receives a wireless signal via the antenna 810.
[0486] The wireless communication interface 825 may include a
plurality of the BB processors 826 as illustrated in FIG. 45, and
the plurality of BB processors 826 may, for example, correspond to
a plurality of frequency bands used by the eNB 800. The wireless
communication interface 825 may also include a plurality of the RF
circuits 827, as illustrated in FIG. 45, and the plurality of RF
circuits 827 may, for example, correspond to a plurality of antenna
elements. FIG. 45 illustrates an example in which the wireless
communication interface 825 includes the plurality of BB processors
826 and the plurality of RF circuits 827, but the wireless
communication interface 825 may include the single BB processor 826
or the single RF circuit 827.
[0487] In the eNB 800 illustrated in FIG. 45, one or more
components included in the processing unit 250 described above with
reference to FIG. 16 (the information acquiring unit 251 and/or the
control unit 253) may be mounted in the wireless communication
interface 825. Alternatively, at least some of the components may
be mounted in the controller 821. As an example, the eNB 800 may be
equipped with a module including some or all components of the
wireless communication interface 825 (for example, the BB processor
826) and/or the controller 821, and one or more of the components
above may be mounted in the module. In this case, the module may
store a program causing the processor to function as one or more of
the components above (that is, a program causing the processor to
perform the operation of one or more of the components above) and
execute the program. As another example, the program causing the
processor to function as one or more of the components above may be
installed in the eNB 800, and the wireless communication interface
825 (for example, the BB processor 826) and/or the controller 821
may execute the program. As described above, the eNB 800, the base
station apparatus 820, or the module may be provided as an
apparatus including one or more of the components above, and the
program causing the processor to function as one or more of the
components above may be provided. A readable recording medium in
which the program is recorded may be provided. For these points,
one or more components included in the processing unit 260
described above with reference to FIG. 26 (the information
acquiring unit 261 and/or the control unit 263), and one or more
components included in the processing unit 270 described above with
reference to FIG. 36 (the information acquiring unit 271 and/or the
control unit 273) are the same as one or more of the components
above included in the processing unit 250.
[0488] In the eNB 800 illustrated in FIG. 45, the wireless
communication unit 220 described above with reference to FIG. 16
may be mounted in the wireless communication interface 825 (for
example, the RF circuit 827). The antenna unit 210 may be mounted
in the antenna 810. The network communication unit 230 may be
mounted in the controller 821 and/or the network interface 823.
Second Application Example
[0489] FIG. 46 is a block diagram illustrating a second example of
a schematic configuration of an eNB to which the technology
according to the present disclosure may be applied. An eNB 830
includes one or more antennas 840, a base station apparatus 850,
and an RRH 860. Each of the antennas 840 and the RRH 860 may be
connected to each other via an RF cable. The base station apparatus
850 and the RRH 860 may be connected to each other by a high speed
line such as optical fiber cables.
[0490] Each of the antennas 840 includes a single or a plurality of
antenna elements (e.g. antenna elements constituting a MIMO
antenna), and is used for the RRH 860 to transmit and receive a
wireless signal. The eNB 830 may include a plurality of the
antennas 840 as illustrated in FIG. 46, and the plurality of
antennas 840 may, for example, correspond to a plurality of
frequency bands used by the eNB 830. FIG. 46 illustrates an example
in which the eNB 830 includes the plurality of antennas 840, but
the eNB 830 may include the single antenna 840.
[0491] The base station apparatus 850 includes a controller 851, a
memory 852, a network interface 853, a wireless communication
interface 855, and a connection interface 857. The controller 851,
the memory 852, and the network interface 853 are the same as the
controller 821, the memory 822, and the network interface 823
described with reference to FIG. 45.
[0492] The wireless communication interface 855 supports a cellular
communication system such as LTE and LTE-Advanced, and provides
wireless connection to a terminal located in a sector corresponding
to the RRH 860 via the RRH 860 and the antenna 840. The wireless
communication interface 855 may typically include a BB processor
856. The BB processor 856 is the same as the BB processor 826
described with reference to FIG. 45 except that the BB processor
856 is connected to an RF circuit 864 of the RRH 860 via the
connection interface 857. The wireless communication interface 855
may include a plurality of the BB processors 856, as illustrated in
FIG. 46, and the plurality of BB processors 856 may, for example,
correspond to a plurality of frequency bands used by the eNB 830
respectively. FIG. 46 illustrates an example in which the wireless
communication interface 855 includes the plurality of BB processors
856, but the wireless communication interface 855 may include the
single BB processor 856.
[0493] The connection interface 857 is an interface for connecting
the base station apparatus 850 (wireless communication interface
855) to the RRH 860 The connection interface 857 may be a
communication module for communication on the high speed line which
connects the base station apparatus 850 (wireless communication
interface 855) to the RRH 860.
[0494] The RRH 860 includes a connection interface 861 and a
wireless communication interface 863.
[0495] The connection interface 861 is an interface for connecting
the RRH 860 (wireless communication interface 863) to the base
station apparatus 850. The connection interface 861 may be a
communication module for communication on the high speed line.
[0496] The wireless communication interface 863 transmits and
receives a wireless signal via the antenna 840. The wireless
communication interface 863 may typically include the RF circuit
864. The RF circuit 864 may include a mixer, a filter, an amplifier
and the like, and transmits and receives a wireless signal via the
antenna 840. The wireless communication interface 863 may include a
plurality of the RF circuits 864 as illustrated in FIG. 46, and the
plurality of RF circuits 864 may, for example, correspond to a
plurality of antenna elements. FIG. 46 illustrates an example in
which the wireless communication interface 863 includes the
plurality of RF circuits 864, but the wireless communication
interface 863 may include the single RF circuit 864.
[0497] In the eNB 830 illustrated in FIG. 46, one or more
components included in the processing unit 250 described above with
reference to FIG. 16 (the information acquiring unit 251 and/or the
control unit 253) may be mounted in the wireless communication
interface 855 and/or the wireless communication interface 863.
Alternatively, at least some of the components may be mounted in
the controller 851. As an example, the eNB 830 may be equipped with
a module including some or all components of the wireless
communication interface 855 (for example, the BB processor 856)
and/or the controller 851, and one or more of the components above
may be mounted in the module. In this case, the module may store a
program causing the processor to function as one or more of the
components above (that is, a program causing the processor to
perform the operation of one or more of the components above) and
execute the program. As another example, the program causing the
processor to function as one or more of the components above may be
installed in the eNB 830, and the wireless communication interface
855 (for example, the BB processor 856) and/or the controller 851
may execute the program. As described above, the eNB 830, the base
station apparatus 850, or the module may be provided as an
apparatus including one or more of the components above, and the
program causing the processor to function as one or more of the
components above may be provided. A readable recording medium in
which the program is recorded may be provided. In these points, one
or more components included in the processing unit 260 described
above with reference to FIG. 26 (the information acquiring unit 261
and/or the control unit 263), and one or more components included
in the processing unit 270 described above with reference to FIG.
36 (the information acquiring unit 271 and/or the control unit 273)
are the same as one or more of the components above included in the
processing unit 250.
[0498] In the eNB 830 illustrated in FIG. 46, the wireless
communication unit 220 described above with reference to FIG. 16
may be mounted in the wireless communication interface 863 (for
example, the RF circuit 864). The antenna unit 210 may be mounted
in the antenna 840. The network communication unit 230 may be
mounted in the controller 851 and/or the network interface 853
7.3. Application Examples for Terminal Device
First Application Example
[0499] FIG. 47 is a block diagram illustrating an example of a
schematic configuration of a smartphone 900 to which the technology
according to the present disclosure may be applied. The smartphone
900 includes a processor 901, a memory 902, a storage 903, an
external connection interface 904, a camera 906, a sensor 907, a
microphone 908, an input device 909, a display device 910, a
speaker 911, a wireless communication interface 912, one or more
antenna switches 915, one or more antennas 916, a bus 917, a
battery 918, and a secondary controller 919.
[0500] The processor 901 may be, for example, a CPU or a system on
chip (SoC), and controls the functions of an application layer and
other layers of the smartphone 900. The memory 902 includes a RAM
and a ROM, and stores a program executed by the processor 901 and
data. The storage 903 may include a storage medium such as
semiconductor memories and hard disks. The external connection
interface 904 is an interface for connecting the smartphone 900 to
an externally attached device such as memory cards and universal
serial bus (USB) devices.
[0501] The camera 906 includes an image sensor such as charge
coupled devices (CCDs) and complementary metal oxide semiconductor
(CMOS), and generates a captured image. The sensor 907 may include
a sensor group including, for example, a positioning sensor, a gyro
sensor, a geomagnetic sensor, and an acceleration sensor. The
microphone 908 converts a sound that is input into the smartphone
900 to an audio signal. The input device 909 includes, for example,
a touch sensor which detects that a screen of the display device
910 is touched, a key pad, a keyboard, a button, or a switch, and
accepts an operation or an information input from a user. The
display device 910 includes a screen such as liquid crystal
displays (LCDs) and organic light emitting diode (OLED) displays,
and displays an output image of the smartphone 900. The speaker 911
converts the audio signal that is output from the smartphone 900 to
a sound
[0502] The wireless communication interface 912 supports a cellular
communication system such as LTE or LTE-Advanced, and performs
wireless communication. The wireless communication interface 912
may typically include the BB processor 913, the RF circuit 914, and
the like. The BB processor 913 may, for example, perform
encoding/decoding, modulation/demodulation,
multiplexing/demultiplexing, and the like, and performs a variety
of types of signal processing for wireless communication. On the
other hand, the RF circuit 914 may include a mixer, a filter, an
amplifier, and the like, and transmits and receives a wireless
signal via the antenna 916. The wireless communication interface
912 may be a one-chip module in which the BB processor 913 and the
RF circuit 914 are integrated. The wireless communication interface
912 may include a plurality of BB processors 913 and a plurality of
RF circuits 914 as illustrated in FIG. 47. FIG. 47 illustrates an
example in which the wireless communication interface 912 includes
a plurality of BB processors 913 and a plurality of RF circuits
914, but the wireless communication interface 912 may include a
single BB processor 913 or a single RF circuit 914.
[0503] Further, the wireless communication interface 912 may
support other types of wireless communication system such as a
short range wireless communication system, a near field
communication system, and a wireless local area network (LAN)
system in addition to the cellular communication system, and in
this case, the wireless communication interface 912 may include the
BB processor 913 and the RF circuit 914 for each wireless
communication system.
[0504] Each antenna switch 915 switches a connection destination of
the antenna 916 among a plurality of circuits (for example,
circuits for different wireless communication systems) included in
the wireless communication interface 912.
[0505] Each of the antennas 916 includes one or more antenna
elements (for example, a plurality of antenna elements constituting
a MIMO antenna) and is used for transmission and reception of the
wireless signal by the wireless communication interface 912. The
smartphone 900 may include a plurality of antennas 916 as
illustrated in FIG. 47. FIG. 47 illustrates an example in which the
smartphone 900 includes a plurality of antennas 916, but the
smartphone 900 may include a single antenna 916.
[0506] Further, the smartphone 900 may include the antenna 916 for
each wireless communication system. In this case, the antenna
switch 915 may be omitted from a configuration of the smartphone
900.
[0507] The bus 917 connects the processor 901, the memory 902, the
storage 903, the external connection interface 904, the camera 906,
the sensor 907, the microphone 908, the input device 909, the
display device 910, the speaker 911, the wireless communication
interface 912, and the secondary controller 919 to each other. The
battery 918 supplies electric power to each block of the smartphone
900 illustrated in FIG. 47 via a feeder line that is partially
illustrated in the figure as a dashed line. The secondary
controller 919, for example, operates a minimally necessary
function of the smartphone 900 in a sleep mode.
[0508] In the smartphone 900 illustrated in FIG. 47, one or more
components included in the processing unit 140 described above with
reference to FIG. 12 (the information acquiring unit 141, the
measurement unit 143, and/or the reporting unit 145) may be mounted
in the wireless communication interface 912. Alternatively, at
least some of the components may be mounted in the processor 901 or
the secondary controller 919. As an example, the smartphone 900 may
be equipped with a module including some or all components of the
wireless communication interface 912 (for example, the BB processor
913), the processor 901, and/or the secondary controller 919, and
one or more of the components above may be mounted in the module.
In this case, the module may store a program causing the processor
to function as one or more of the components above (that is, a
program causing the processor to perform the operation of one or
more of the components above) and execute the program. As another
example, the program causing the processor to function as one or
more of the components above may be installed in the smartphone
900, and the wireless communication interface 912 (for example, the
BB processor 913), the processor 901, and/or the secondary
controller 919 may execute the program. As described above, the
smartphone 900 or the module may be provided as an apparatus
including one or more of the components above, and the program
causing the processor to function as one or more of the components
above may be provided. A readable recording medium in which the
program is recorded may be provided. For these points, one or more
components included in the processing unit 150 described above with
reference to FIG. 22 (the information acquiring unit 151, the
measurement unit 153, and/or the reporting unit 155), one or more
components included in the processing unit 160 described above with
reference to FIG. 31 (the information acquiring unit 161, the
measurement unit 163, and/or the reporting unit 165), and one or
more components included in the processing unit 170 described above
with reference to FIG. 41 (the information acquiring unit 171, the
measurement unit 173, and/or the reporting unit 175) are the same
as one or more of the components above included in the processing
unit 140.
[0509] In the smartphone 900 illustrated in FIG. 47, for example,
the wireless communication unit 120 described above with reference
to FIG. 12 may be mounted in the wireless communication interface
912 (for example, the RF circuit 914) The antenna unit 110 may be
mounted in the antenna 916.
Second Application Example
[0510] FIG. 48 is a block diagram illustrating an example of a
schematic configuration of a car navigation apparatus 920 to which
the technology according to the present disclosure may be applied.
The car navigation apparatus 920 includes a processor 921, a memory
922, a global positioning system (GPS) module 924, a sensor 925, a
data interface 926, a content player 927, a storage medium
interface 928, an input device 929, a display device 930, a speaker
931, a wireless communication interface 933, one or more antenna
switches 936, one or more antennas 937, and a battery 938.
[0511] The processor 921 may be, for example, a CPU or an SoC, and
controls the navigation function and the other functions of the car
navigation apparatus 920. The memory 922 includes a RAM and a ROM,
and stores a program executed by the processor 921 and data.
[0512] The GPS module 924 uses a GPS signal received from a GPS
satellite to measure the position (e.g. latitude, longitude, and
altitude) of the car navigation apparatus 920. The sensor 925 may
include a sensor group including, for example, a gyro sensor, a
geomagnetic sensor, and an air pressure sensor. The data interface
926 is, for example, connected to an in-vehicle network 941 via a
terminal that is not illustrated, and acquires data such as vehicle
speed data generated on the vehicle side.
[0513] The content player 927 reproduces content stored in a
storage medium (e.g. CD or DVD) inserted into the storage medium
interface 928. The input device 929 includes, for example, a touch
sensor which detects that a screen of the display device 930 is
touched, a button, or a switch, and accepts operation or
information input from a user. The display device 930 includes a
screen such as LCDs and OLED displays, and displays an image of the
navigation function or the reproduced content. The speaker 931
outputs a sound of the navigation function or the reproduced
content.
[0514] The wireless communication interface 933 supports a cellular
communication system such as LTE or LTE-Advanced, and performs
wireless communication. The wireless communication interface 933
may typically include the BB processor 934, the RF circuit 935, and
the like. The BB processor 934 may, for example, perform
encoding/decoding, modulation/demodulation,
multiplexing/demultiplexing, and the like, and performs a variety
of types of signal processing for wireless communication. On the
other hand, the RF circuit 935 may include a mixer, a filter, an
amplifier, and the like, and transmits and receives a wireless
signal via the antenna 937. The wireless communication interface
933 may be a one-chip module in which the BB processor 934 and the
RF circuit 935 are integrated. The wireless communication interface
933 may include a plurality of BB processors 934 and a plurality of
RF circuits 935 as illustrated in FIG. 48. FIG. 48 illustrates an
example in which the wireless communication interface 933 includes
a plurality of BB processors 934 and a plurality of RF circuits
935, but the wireless communication interface 933 may be a single
BB processor 934 or a single RF circuit 935.
[0515] Further, the wireless communication interface 933 may
support other types of wireless communication system such as a
short range wireless communication system, a near field
communication system, and a wireless LAN system in addition to the
cellular communication system, and in this case, the wireless
communication interface 933 may include the BB processor 934 and
the RF circuit 935 for each wireless communication system.
[0516] Each antenna switch 936 switches a connection destination of
the antenna 937 among a plurality of circuits (for example,
circuits for different wireless communication systems) included in
the wireless communication interface 933.
[0517] Each of the antennas 937 includes one or more antenna
elements (for example, a plurality of antenna elements constituting
a MIMO antenna) and is used for transmission and reception of the
wireless signal by the wireless communication interface 933. The
car navigation apparatus 920 includes a plurality of antennas 937
as illustrated in FIG. 48. FIG. 48 illustrates an example in which
the car navigation apparatus 920 includes a plurality of antennas
937, but the car navigation apparatus 920 may include a single
antenna 937.
[0518] Further, the smartphone 920 may include the antenna 937 for
each wireless communication system. In this case, the antenna
switch 936 may be omitted from a configuration of the car
navigation apparatus 920.
[0519] The battery 950 supplies electric power to each block of the
car navigation apparatus 930 illustrated in FIG. 48 via a feeder
line that is partially illustrated in the figure as a dashed line.
The battery 950 accumulates the electric power supplied from the
vehicle.
[0520] In the car navigation apparatus 920 illustrated in FIG. 48,
one or more components included in the processing unit 140
described above with reference to FIG. 12 (the information
acquiring unit 141, the measurement unit 143, and/or the reporting
unit 145) may be mounted in the wireless communication interface
933. Alternatively, at least some of the components may be mounted
in the processor 921. As an example, the car navigation apparatus
920 may be equipped with a module including some or all components
of the wireless communication interface 933 (for example, the BB
processor 934), and/or the processor 921, and one or more of the
components above may be mounted in the module. In this case, the
module may store a program causing the processor to function as one
or more of the components above (that is, a program causing the
processor to perform the operation of one or more of the components
above) and execute the program. As another example, the program
causing the processor to function as one or more of the components
above may be installed in the car navigation apparatus 920, and the
wireless communication interface 933 (for example, the BB processor
934), and/or the processor 921 may execute the program. As
described above, the car navigation apparatus 920 or the module may
be provided as an apparatus including one or more of the components
above, and the program causing the processor to function as one or
more of the components above may be provided. A readable recording
medium in which the program is recorded may be provided. For these
points, one or more components included in the processing unit 150
described above with reference to FIG. 22 (the information
acquiring unit 151, the measurement unit 153, and/or the reporting
unit 155), one or more components included in the processing unit
160 described above with reference to FIG. 31 (the information
acquiring unit 161, the measurement unit 163, and/or the reporting
unit 165), and one or more components included in the processing
unit 170 described above with reference to FIG. 41 (the information
acquiring unit 171, the measurement unit 173, and/or the reporting
unit 175) are the same as one or more of the components above
included in the processing unit 140.
[0521] In the car navigation apparatus 920 illustrated in FIG. 48,
for example, the wireless communication unit 120 described above
with reference to FIG. 12 may be mounted in the wireless
communication interface 933 (for example, the RF circuit 935). The
antenna unit 110 may be mounted in the antenna 937.
[0522] Further, the technique according to the present disclosure
may be implemented as an in-vehicle system (or a vehicle) 940
including one or more blocks of the above-described car navigation
apparatus 920, an in-vehicle network 941 and a vehicle side module
942. That is, the in-vehicle system (or the vehicle) 940 may be
provided as an apparatus including one more of the components above
included in the processing unit 140 (or the processing unit 150,
the processing unit 160 or the processing unit 170). The vehicle
side module 942 generates vehicle side data such as vehicle speed,
engine speed and failure information and outputs the generated data
to the in-vehicle network 961.
8. CONCLUSION
[0523] The communication apparatuses and each process according to
the embodiments of the present disclosure have been described above
with reference to FIGS. 9 to 48.
[0524] According to the first embodiment, measurement of each of
one or more frequency bands that are a part of a plurality of
frequency bands that are not used by the terminal device 100-1 is
performed. The terminal device 100-1 does not perform measurement
of each of the remaining frequency bands among the plurality of
frequency bands or performs the measurement of each of the
remaining frequency bands at a frequency lower than a frequency of
the measurements of each of the one or more frequency bands.
[0525] According to the second embodiment and the third embodiment,
the terminal device 100-2 performs measurement of a first frequency
band based on a discovery reference signal transmitted in the first
frequency band within a first period included in a measurement gap,
and performs measurement of a second frequency band based on a
reference signal transmitted in the second frequency band within a
second period included in the measurement gap. Specifically, in the
second embodiment, the reference signal transmitted in the second
frequency band is a DRS. Conversely, specifically, in the third
embodiment, the measurement gap is an extended measurement gap.
[0526] According to the fourth embodiment, the terminal device
100-4 performs first measurement of each of a plurality of
frequency bands and performs second measurement of each of one or
more frequency bands that are a part of the plurality of frequency
bands. The first measurement is measurement that is performed based
on a reference signal transmitted within a period having a first
length. The second measurement is measurement that is performed
based on a reference signal transmitted within a period having a
second length that is greater than the first length.
[0527] According to each of the first to fourth embodiments, it is
possible to improve measurement performed by the terminal device
100.
[0528] The preferred embodiment of the present disclosure has been
described above with reference to the accompanying drawings, whilst
the present disclosure is not limited to the above examples. A
person skilled in the art may find various alterations and
modifications within the scope of the appended claims, and it
should be understood that they will naturally come under the
technical scope of the present disclosure.
[0529] For example, while an example in which a communication
system supports LTE or LTE-A has been described in embodiments of
the present disclosure, the present disclosure is not limited
thereto. For example, the communication system may be a system that
supports another communication standard.
[0530] Further, it is not always necessary to execute the
processing steps in the processing in the present specification in
chronological order in order described in the flowcharts or the
sequence diagrams. For example, the processing steps in the
above-described processing may be executed in order different from
the order described in the flowcharts or the sequence diagrams or
may be executed in parallel.
[0531] Further, it is also possible to create a computer program
for making a processor (such as, for example, a CPU and a DSP)
provided at apparatuses (such as, for example, the terminal device,
the base station or the control entity, or the modules thereof) in
the present specification function as the above-described
apparatuses (in other words, a computer program for making the
processor execute operation of the components of the
above-described apparatuses). Further, it is also possible to
provide a recording medium having the above-described computer
program recorded therein. Further, it is also possible to provide
an apparatus (such as, for example, a finished product and a module
(such as parts, processing circuits and chips) for the finished
product) including a memory having the above-described computer
program stored therein and one or more processors which can execute
the above-described computer program. Further, a method including
the operation of one or more of the components (for example, a
measurement unit and/or a reporting unit, or an information
acquiring unit and/or the control unit) of the above-described
apparatuses is included in the technique according to the present
disclosure.
[0532] In addition, the effects described in the present
specification are merely illustrative and demonstrative, and not
limitative. In other words, the technology according to the present
disclosure can exhibit other effects that are evident to those
skilled in the art along with or instead of the effects based on
the present specification
[0533] Additionally, the present technology may also be configured
as below.
(1)
[0534] A device including:
[0535] a measurement unit configured to perform measurement of each
of one or more frequency bands that are a part of a plurality of
frequency bands that are not used by a terminal device,
[0536] wherein the measurement unit does not perform measurement of
each of remaining frequency bands among the plurality of frequency
bands or performs the measurement of each of the remaining
frequency bands at a frequency lower than a frequency of the
measurements of each of the one or more frequency bands.
(2)
[0537] The device according to (1),
[0538] wherein the measurement unit does not perform the
measurement of each of the remaining frequency bands.
(3)
[0539] The device according to (2), further including:
[0540] a reporting unit configured to report a result of the
measurement of each of the one or more frequency bands to a base
station,
[0541] wherein the reporting unit substitutes a result of
measurement of a first frequency band included in the one or more
frequency bands with a result of measurement of a second frequency
band included in the remaining frequency bands, and thus reports
the result of the measurement of the second frequency band to the
base station.
(4)
[0542] The device according to (1),
[0543] wherein the measurement unit performs the measurement of
each of the remaining frequency bands at a frequency lower than the
frequency of the measurements of each of the one or more frequency
bands.
(5)
[0544] The device according to (4),
[0545] wherein the measurement unit performs the measurement of
each of the remaining frequency bands using fewer measurement gaps
than measurement gaps used for the measurement of each of the one
or more frequency bands.
(6)
[0546] The device according to (5),
[0547] wherein the measurement unit skips a part of measurement
gaps assigned to each of the remaining frequency bands without
measurement.
(7)
[0548] The device according to (5),
[0549] wherein measurement gaps assigned to each of the remaining
frequency bands are fewer than measurement gaps assigned to each of
the one or more frequency bands
(8)
[0550] The device according to any one of (1) to (7),
[0551] wherein the measurement of each of the one or more frequency
bands is measurement based on a reference signal transmitted in
each of the one or more frequency bands, and
[0552] the measurement of each of the remaining frequency bands is
measurement based on a reference signal transmitted in each of the
remaining frequency bands.
(9)
[0553] The device according to (8),
[0554] wherein the reference signal is a cell-specific reference
signal.
(10)
[0555] The device according to (8),
[0556] wherein the reference signal is a discovery reference
signal.
(11)
[0557] The device according to any one of (1) to (10),
[0558] wherein the remaining frequency bands are frequency bands
included in the same operating band as the one or more frequency
bands.
(12)
[0559] The device according to (11),
[0560] wherein each of the remaining frequency bands is a frequency
band that is adjacent to any frequency band included in the one or
more frequency bands.
(13)
[0561] The device according to any one of (1) to (12),
[0562] wherein each of the plurality of frequency bands is a
frequency band that is used by a base station of a small cell.
(14)
[0563] A device including:
[0564] an acquiring unit configured to acquire information about a
plurality of frequency bands that are not used by a terminal
device; and
[0565] a control unit configured to instruct the terminal device to
perform measurement of each of one or more frequency bands that are
a part of the plurality of frequency bands, and not to perform
measurement of each of remaining frequency bands among the
plurality of frequency bands or to perform the measurement of each
of the remaining frequency bands at a frequency lower than a
frequency of the measurements of each of the one or more frequency
bands.
(15)
[0566] The device according to (14),
[0567] wherein the control unit instructs the terminal device to
perform the measurement of each of the one or more frequency bands
and not to perform the measurement of each of the remaining
frequency bands,
[0568] the control unit substitutes a result of measurement of a
first frequency band included in the one or more frequency bands
with a result of measurement of a second frequency band included in
the remaining frequency bands.
(16)
[0569] The device according to (14) or (15),
[0570] wherein the control unit instructs the terminal device to
skip a part of measurement gaps assigned to each of the remaining
frequency bands without measurement.
(17)
[0571] A device including:
[0572] a measurement unit configured to perform measurement of a
first frequency band based on a discovery reference signal
transmitted in the first frequency band within a first period
included in a measurement gap and perform measurement of a second
frequency band based on a reference signal transmitted in the
second frequency band within a second period included in the
measurement gap.
(18)
[0573] The device according to (17),
[0574] wherein the measurement gap is an extended measurement
gap
(19)
[0575] The device according to (18),
[0576] wherein the extended measurement gap is a period longer than
6 milliseconds.
(20)
[0577] The device according to (18) or (19),
[0578] wherein the reference signal transmitted in the second
frequency band is a cell-specific reference signal.
(21)
[0579] The device according to (20),
[0580] wherein the first period is a period shorter than the second
period.
(22)
[0581] The device according to (17),
[0582] wherein the reference signal transmitted in the second
frequency band is a discovery reference signal.
(23)
[0583] The device according to (22),
[0584] wherein the measurement gap is a period having a length of 6
milliseconds.
(24)
[0585] The device according to any one of (17) to (23),
[0586] wherein the measurement unit performs the measurement of the
first frequency band that is used by the same base station based on
a discovery reference signal and a cell-specific reference signal
transmitted by the same base station in the first frequency band
within the first period or performs the measurement of the second
frequency band that is used by the same base station based on a
discovery reference signal and a cell-specific reference signal
transmitted by the same base station in the second frequency band
within the second period
(25)
[0587] The device according to (24),
[0588] wherein at least one of the first period and the second
period is a period shorter than 6 milliseconds
(26)
[0589] The device according to any one of (17) to (25),
[0590] wherein the measurement unit performs measurement of a
frequency group and measurement of one or more other frequency
bands or measurement of one or more other frequency groups based on
a priority of the frequency group including the first frequency
band and the second frequency band and a priority of the one or
more other frequency bands or a priority of the one or more other
frequency groups.
(27)
[0591] The device according to (26),
[0592] wherein the measurement unit performs the measurement of the
frequency group and the measurement of the one or more other
frequency bands or the measurement of the one or more other
frequency groups in consideration of a transmission period in which
a discovery reference signal is transmitted in the first frequency
band.
(28)
[0593] The device according to (27),
[0594] wherein the measurement unit performs measurement of another
frequency band or another frequency group whose priority is lower
than the frequency group before the measurement of the frequency
group outside of the transmission period.
(29)
[0595] The device according to any one of (17) to (18),
[0596] wherein the measurement gap includes an additional period,
and the measurement unit performs measurement of an additional
frequency band based on a discovery reference signal transmitted in
the additional frequency band within the additional period.
(30)
[0597] A device including:
[0598] an acquiring unit configured to acquire information
indicating a first frequency band in which a discovery reference
signal is transmitted within at least a first period included in a
measurement gap; and
[0599] a control unit configured to notify a terminal device of the
first frequency band and the measurement gap.
(31)
[0600] The device according to (30),
[0601] wherein the measurement gap further includes a second period
in which a reference signal is transmitted in a second frequency
band.
(32)
[0602] The device according to (30) or (31),
[0603] wherein the measurement gap is an extended measurement
gap.
(33)
[0604] The device according to (32),
[0605] wherein the measurement gap includes a second period in
which a cell-specific reference signal is transmitted in a second
frequency band.
(34)
[0606] The device according to any one of (30) to (32),
[0607] wherein the acquiring unit acquires information indicating a
frequency group including the first frequency band and a second
frequency band, and
[0608] the control unit notifies a terminal device of the frequency
group and the measurement gap
(35)
[0609] The device according to (34),
[0610] wherein the second frequency band is a frequency band in
which a discovery reference signal is transmitted within at least a
second period included in the measurement gap
(36)
[0611] The device according to (34) or (35),
[0612] wherein the control unit notifies a terminal device of a
priority of the frequency group and a priority of one or more other
frequency bands or a priority of one or more other frequency
groups.
(37)
[0613] A device including:
[0614] an acquiring unit configured to acquire information about a
first frequency band in which a discovery reference signal is
transmitted; and
[0615] a control unit configured to decide an extended measurement
gap including at least a part of a transmission period in which a
discovery reference signal is transmitted in the first frequency
band.
(38)
[0616] The device according to (37),
[0617] wherein the control unit controls the transmission period
such that at least a part of the transmission period is included in
the extended measurement gap.
(39)
[0618] The device according to (37),
[0619] wherein the information about the first frequency band
includes information indicating the transmission period, and
[0620] the control unit decides the extended measurement gap based
on the transmission period.
(40)
[0621] A device including:
[0622] an acquiring unit configured to acquire information about
two or more frequency bands in which a discovery reference signal
is transmitted; and
[0623] a control unit configured to decide a frequency group
including at least a first frequency band and a second frequency
band among the two or more frequency bands,
[0624] wherein the first frequency band is a frequency band in
which a discovery reference signal is transmitted within at least a
first period included in a measurement gap, and
[0625] the second frequency band is a frequency band in which a
discovery reference signal is transmitted within at least a second
period included in the measurement gap
(41)
[0626] The device according to (40),
[0627] wherein the control unit controls a transmission period in
which a discovery reference signal is transmitted in the first
frequency band such that the discovery reference signal is
transmitted in the first frequency band within at least the first
period, or controls a transmission period in which a discovery
reference signal is transmitted in the second frequency band such
that the discovery reference signal is transmitted in the second
frequency band within at least the second period.
(42)
[0628] The device according to (40),
[0629] wherein the information about the two or more frequency
bands includes information indicating a transmission period in
which a discovery reference signal is transmitted in each of the
two or more frequency bands, and
[0630] the control unit decides the frequency group based on the
transmission period.
(43)
[0631] A device including:
[0632] a measurement unit configured to perform first measurement
of each of a plurality of frequency bands and perform second
measurement of each of one or more frequency bands that are a part
of the plurality of frequency bands,
[0633] wherein the first measurement is measurement that is
performed based on a reference signal transmitted within a period
having a first length, and
[0634] the second measurement is measurement that is performed
based on a reference signal transmitted within a period having a
second length that is greater than the first length.
(44)
[0635] The device according to (43),
[0636] wherein the one or more frequency bands are frequency bands
that are selected from among the plurality of frequency bands based
on a result of the first measurement.
(45)
[0637] The device according to (44),
[0638] wherein the one or more frequency bands are frequency bands
the first measurement of which has a more favorable result.
(46)
[0639] The device according to any one of (43) to (45),
[0640] wherein the device is a terminal device or a module for the
terminal device, and
[0641] each of the plurality of frequency bands is a frequency band
that is not used by the terminal device.
(47)
[0642] The device according to (46),
[0643] wherein the period having the first length is a period
including a measurement gap of a first number, and
[0644] the period having the second length is a period including a
measurement gap of a second number that is greater than the first
number.
(48)
[0645] The device according to any one of (43) to (47),
[0646] wherein each of the plurality of frequency bands is a
frequency band that is used by a base station of a small cell.
(49)
[0647] The device according to (48),
[0648] wherein the reference signal is a discovery reference
signal.
(50)
[0649] The device according to any one of (43) to (48),
[0650] wherein the reference signal is a cell-specific reference
signal.
(51)
[0651] The device according to any one of (1) to (13),
[0652] wherein the device is the terminal device or a module for
the terminal device.
(52)
[0653] A method including:
[0654] performing, by a processor, measurement of each of one or
more frequency bands that are a part of a plurality of frequency
bands that are not used by a terminal device; and
[0655] not performing, by a processor, measurement of each of
remaining frequency bands among the plurality of frequency bands or
performing the measurement of each of the remaining frequency bands
at a frequency lower than a frequency of the measurements of each
of the one or more frequency bands.
(53)
[0656] A program for causing a processor to execute:
[0657] performing measurement of each of one or more frequency
bands that are a part of a plurality of frequency bands that are
not used by a terminal device; and
[0658] not performing measurement of each of remaining frequency
bands among the plurality of frequency bands or performing the
measurement of each of the remaining frequency bands at a frequency
lower than a frequency of the measurements of each of the one or
more frequency bands.
(54)
[0659] A readable recording medium having a program recorded
thereon, the program causing a processor to execute:
[0660] performing measurement of each of one or more frequency
bands that are a part of a plurality of frequency bands that are
not used by a terminal device; and
[0661] not performing measurement of each of remaining frequency
bands among the plurality of frequency bands or performing the
measurement of each of the remaining frequency bands at a frequency
lower than a frequency of the measurements of each of the one or
more frequency bands.
(55)
[0662] The device according to any one of (14) to (16),
[0663] wherein the device is a base station, a base station device
for the base station or a module for the base station device.
(56)
[0664] A method including:
[0665] acquiring information about a plurality of frequency bands
that are not used by a terminal device; and
[0666] instructing, by a processor, the terminal device to perform
measurement of each of one or more frequency bands that are a part
of the plurality of frequency bands, and not to perform measurement
of each of remaining frequency bands among the plurality of
frequency bands or to perform the measurement of each of the
remaining frequency bands at a frequency lower than a frequency of
the measurements of each of the one or more frequency bands.
(57)
[0667] A program for causing a processor to execute:
[0668] acquiring information about a plurality of frequency bands
that are not used by a terminal device; and
[0669] instructing the terminal device to perform measurement of
each of one or more frequency bands that are a part of the
plurality of frequency bands, and not to perform measurement of
each of remaining frequency bands among the plurality of frequency
bands or to perform the measurement of each of the remaining
frequency bands at a frequency lower than a frequency of the
measurements of each of the one or more frequency bands.
(58)
[0670] A readable medium having a program recorded thereon, the
program causing a processor to execute:
[0671] acquiring information about a plurality of frequency bands
that are not used by a terminal device; and
[0672] instructing the terminal device to perform measurement of
each of one or more frequency bands that are a part of the
plurality of frequency bands, and not to perform measurement of
each of remaining frequency bands among the plurality of frequency
bands or to perform the measurement of each of the remaining
frequency bands at a frequency lower than a frequency of the
measurements of each of the one or more frequency bands.
(59)
[0673] The device according to any one of (17) to (29),
[0674] wherein the device is a terminal device or a module for the
terminal device
(60)
[0675] A method including:
[0676] performing, by a processor, measurement of a first frequency
band based on a discovery reference signal transmitted in the first
frequency band within a first period included in a measurement gap;
and
[0677] performing, by a processor, measurement of a second
frequency band based on a reference signal transmitted in the
second frequency band within a second period included in the
measurement gap.
(61)
[0678] A program for causing a processor to execute:
[0679] performing measurement of a first frequency band based on a
discovery reference signal transmitted in the first frequency band
within a first period included in a measurement gap; and
[0680] performing measurement of a second frequency band based on a
reference signal transmitted in the second frequency band within a
second period included in the measurement gap.
(62)
[0681] A readable recording medium having a program recorded
thereon, the program causing a processor to execute:
[0682] performing measurement of a first frequency band based on a
discovery reference signal transmitted in the first frequency band
within a first period included in a measurement gap; and
[0683] performing measurement of a second frequency band based on a
reference signal transmitted in the second frequency band within a
second period included in the measurement gap.
(63)
[0684] The device according to any one of (30) to (36),
[0685] wherein the device is a base station, a base station device
for the base station or a module for the base station device.
(64)
[0686] A method including:
[0687] acquiring information indicating a first frequency band in
which a discovery reference signal is transmitted within at least a
first period included in a measurement gap; and
[0688] notifying, by a processor, a terminal device of the first
frequency band and the measurement gap.
(65)
[0689] A program for causing a processor to execute:
[0690] acquiring information indicating a first frequency band in
which a discovery reference signal is transmitted within at least a
first period included in a measurement gap; and
[0691] notifying a terminal device of the first frequency band and
the measurement gap.
(66)
[0692] A readable recording medium having a program recorded
thereon, the program causing a processor to execute:
[0693] acquiring information indicating a first frequency band in
which a discovery reference signal is transmitted within at least a
first period included in a measurement gap; and
[0694] notifying a terminal device of the first frequency band and
the measurement gap.
(67)
[0695] The device according to any one of (37) to (39),
[0696] wherein the device is a server, a module for the server, a
base station, a base station device for the base station, or a
module for the base station device.
(68)
[0697] A method including:
[0698] acquiring information about a first frequency band in which
a discovery reference signal is transmitted; and
[0699] deciding, by a processor, an extended measurement gap
including at least a part of a transmission period in which a
discovery reference signal is transmitted in the first frequency
band
(69)
[0700] A program for causing a processor to execute:
[0701] acquiring information about a first frequency band in which
a discovery reference signal is transmitted; and
[0702] deciding an extended measurement gap including at least a
part of a transmission period in which a discovery reference signal
is transmitted in the first frequency band.
(70)
[0703] A readable recording medium having a program recorded
thereon, the program for causing a processor to execute:
[0704] acquiring information about a first frequency band in which
a discovery reference signal is transmitted; and
[0705] deciding an extended measurement gap including at least a
part of a transmission period in which a discovery reference signal
is transmitted in the first frequency band.
(71)
[0706] The device according to any one of (40) to (42),
[0707] wherein the device is a server, a module for the server, a
base station, a base station device for the base station, or a
module for the base station device.
(72)
[0708] A method including:
[0709] acquiring information about two or more frequency bands in
which a discovery reference signal is transmitted; and
[0710] deciding, by a processor, a frequency group including at
least a first frequency band and a second frequency band among the
two or more frequency bands,
[0711] wherein the first frequency band is a frequency band in
which a discovery reference signal is transmitted within at least a
first period included in a measurement gap, and
[0712] the second frequency band is a frequency band in which a
discovery reference signal is transmitted within at least a second
period included in the measurement gap.
(73)
[0713] A program for causing a processor to execute:
[0714] acquiring information about two or more frequency bands in
which a discovery reference signal is transmitted, and
[0715] deciding a frequency group including at least a first
frequency band and a second frequency band among the two or more
frequency bands,
[0716] wherein the first frequency band is a frequency band in
which a discovery reference signal is transmitted within at least a
first period included in a measurement gap, and
[0717] the second frequency band is a frequency band in which a
discovery reference signal is transmitted within at least a second
period included in the measurement gap.
(74)
[0718] A readable recording medium having a program recorded
thereon, the program causing a processor to execute:
[0719] acquiring information about two or more frequency bands in
which a discovery reference signal is transmitted; and
[0720] deciding a frequency group including at least a first
frequency band and a second frequency band among the two or more
frequency bands,
[0721] wherein the first frequency band is a frequency band in
which a discovery reference signal is transmitted within at least a
first period included in a measurement gap, and
[0722] the second frequency band is a frequency band in which a
discovery reference signal is transmitted within at least a second
period included in the measurement gap.
(75)
[0723] The device according to any one of (43) to (50),
[0724] wherein the device is a terminal device or a module for the
terminal device.
(76)
[0725] A method including:
[0726] performing, by a processor, first measurement of each of a
plurality of frequency bands; and
[0727] performing, by a processor, second measurement of each of
one or more frequency bands that are a part of the plurality of
frequency bands,
[0728] wherein the first measurement is measurement that is
performed based on a reference signal transmitted within a period
having a first length, and
[0729] the second measurement is measurement that is performed
based on a reference signal transmitted within a period having a
second length that is greater than the first length.
(77)
[0730] A program for causing a processor to execute:
[0731] performing first measurement of each of a plurality of
frequency bands; and
[0732] performing second measurement of each of one or more
frequency bands that are a part of the plurality of frequency
bands,
[0733] wherein the first measurement is measurement that is
performed based on a reference signal transmitted within a period
having a first length, and
[0734] the second measurement is measurement that is performed
based on a reference signal transmitted within a period having a
second length that is greater than the first length.
(78)
[0735] A readable recording medium having a program recorded
thereon, the program causing a processor to execute:
[0736] performing first measurement of each of a plurality of
frequency bands; and
[0737] performing second measurement of each of one or more
frequency bands that are a part of the plurality of frequency
bands,
[0738] wherein the first measurement is measurement that is
performed based on a reference signal transmitted within a period
having a first length, and
[0739] the second measurement is measurement that is performed
based on a reference signal transmitted within a period having a
second length that is greater than the first length.
REFERENCE SIGNS LIST
[0740] 1 communication system [0741] 100 terminal device [0742]
143, 153, 163, 173 measurement unit [0743] 145, 155, 165, 175
reporting unit [0744] 200 base station [0745] 251, 261, 271
information acquiring unit [0746] 253, 263, 273 control unit [0747]
300 control entity [0748] 331, 341 information acquiring unit
[0749] 333, 343 control unit
* * * * *