U.S. patent application number 16/271103 was filed with the patent office on 2019-06-20 for method and apparatus for receiving system information and paging in mobile communication system.
The applicant listed for this patent is Samsung Electronics Co., Ltd.. Invention is credited to Jaehyuk Jang, Kyeongin Jeong, Sangbum KIM, Soenghun Kim.
Application Number | 20190191410 16/271103 |
Document ID | / |
Family ID | 52432009 |
Filed Date | 2019-06-20 |
![](/patent/app/20190191410/US20190191410A1-20190620-D00000.png)
![](/patent/app/20190191410/US20190191410A1-20190620-D00001.png)
![](/patent/app/20190191410/US20190191410A1-20190620-D00002.png)
![](/patent/app/20190191410/US20190191410A1-20190620-D00003.png)
![](/patent/app/20190191410/US20190191410A1-20190620-D00004.png)
![](/patent/app/20190191410/US20190191410A1-20190620-D00005.png)
![](/patent/app/20190191410/US20190191410A1-20190620-D00006.png)
![](/patent/app/20190191410/US20190191410A1-20190620-D00007.png)
![](/patent/app/20190191410/US20190191410A1-20190620-D00008.png)
![](/patent/app/20190191410/US20190191410A1-20190620-D00009.png)
![](/patent/app/20190191410/US20190191410A1-20190620-D00010.png)
View All Diagrams
United States Patent
Application |
20190191410 |
Kind Code |
A1 |
KIM; Sangbum ; et
al. |
June 20, 2019 |
METHOD AND APPARATUS FOR RECEIVING SYSTEM INFORMATION AND PAGING IN
MOBILE COMMUNICATION SYSTEM
Abstract
A method by a terminal communicating with a first base station
or a second base station is provided. The method includes receiving
a message including information on a time division multiplex (TDM)
pattern on radio resource control (RRC) signaling from the first
base station, and transmitting a signal to a target base station
preconfigured based on the information on the TDM pattern. The
target base station is preconfigured among the first base station
and the second base station, and the message is used to modify an
RRC connection.
Inventors: |
KIM; Sangbum; (Gyeonggi-do,
KR) ; Kim; Soenghun; (Gyeonggi-do, KR) ; Jang;
Jaehyuk; (Gyeonggi-do, KR) ; Jeong; Kyeongin;
(Gyeonggi-do, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd. |
Gyeonggi-do |
|
KR |
|
|
Family ID: |
52432009 |
Appl. No.: |
16/271103 |
Filed: |
February 8, 2019 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14909654 |
Feb 2, 2016 |
|
|
|
PCT/KR2014/006740 |
Jul 24, 2014 |
|
|
|
16271103 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 52/0206 20130101;
Y02D 30/70 20200801; H04W 52/0216 20130101; H04W 52/0245 20130101;
H04W 68/02 20130101; Y02D 70/24 20180101; H04W 76/28 20180201; Y02D
70/1262 20180101; H04W 48/12 20130101; Y02D 70/21 20180101 |
International
Class: |
H04W 68/02 20060101
H04W068/02; H04W 48/12 20060101 H04W048/12; H04W 52/02 20060101
H04W052/02 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 2, 2013 |
KR |
10-2013-0092146 |
Claims
1. A method by a terminal communicating with a first base station
or a second base station, the method comprising: receiving a
message including information on a time division multiplex (TDM)
pattern on radio resource control (RRC) signaling from the first
base station; and transmitting a signal to a target base station
preconfigured based on the information on the TDM pattern, wherein
the target base station is preconfigured among the first base
station and the second base station, and wherein the message is
used to modify an RRC connection.
2. The method of claim 1, wherein transmitting the signal further
comprises: identifying a preconfigured time schedule for
transmitting the signal based on the information on the TDM
pattern; and determining the target base station among the first
base station and the second base station based on the time
schedule.
3. The method of claim 1, wherein the message is an RRC connection
reconfiguration message.
4. A method by a first base station communicating with a terminal,
the method comprising: transmitting a message including information
on a time division multiplex (TDM) pattern on radio resource
control (RRC) signaling to the terminal; and receiving a signal
from the terminal according to a time schedule determined based on
the information on the TDM pattern, wherein the message is used to
modify an RRC connection.
5. The method of claim 4, wherein the message is an RRC connection
reconfiguration message.
6. The method of claim 4, further comprising: transmitting, to a
second base station, the information on the TDM pattern for a
communication between the second base station and the terminal.
7. A terminal communicating with a first base station or a second
base station, the terminal comprising: a transceiver; and a
controller coupled with the transceiver and configured to: control
the transceiver to receive a message including information on a
time division multiplex (TDM) pattern on radio resource control
(RRC) signaling from the first base station, and control the
transceiver to transmit a signal to a target base station
preconfigured based on the information on the TDM pattern, wherein
the target base station is preconfigured among the first base
station and the second base station, and wherein the message is
used to modify an RRC connection.
8. The terminal of claim 7, wherein the controller is further
configured to: identify a preconfigured time schedule for
transmitting the signal based on the information on the TDM
pattern, and determine the target base station among the first base
station and the second base station based on the time schedule.
9. The terminal of claim 7, wherein the message is an RRC
connection reconfiguration message.
10. A first base station communicating with a terminal, the first
base station comprising: a transceiver; and a controller is coupled
with the transceiver and configured to: control the transceiver to
transmit a message including information on a time division
multiplex (TDM) pattern on radio resource control (RRC) signaling
to the terminal, and control the transceiver to receive a signal
from the terminal according to a time schedule determined based on
the information on the TDM pattern, wherein the message is used to
modify an RRC connection.
11. The first base station of claim 10, wherein the message is an
RRC connection reconfiguration message.
12. The first base station of claim 10, wherein the controller is
further configured to control the transceiver to transmit, to a
second base station, the information on the TDM pattern for a
communication between the second base station and the terminal.
Description
PRIORITY
[0001] This application is a Continuation Application of U.S.
patent application Ser. No. 14/909,654, which was filed on Feb. 2,
2016, which is a National Phase Entry of PCT International
Application No. PCT/KR2014/006740, which was filed on Jul. 24,
2014, and claims priority to Korean Patent Application No.
10-2013-0092146, which was filed on Aug. 2, 2013, the contents of
each of which are incorporated herein by reference
TECHNICAL FIELD
[0002] The present disclosure relates to a method and an apparatus
for effectively acquiring system information and paging when a very
long Discontinuous Reception (DRX) cycle is applied in a mobile
communication system. Also, the present disclosure relates to a
method and an apparatus which can more efficiently receive a signal
from a base station according to the mobility of a user equipment
in a mobile communication system.
BACKGROUND ART
[0003] Typically, mobile communication systems have been developed
for the purpose of providing communication while ensuring mobility
of users. Due to the rapid development of technologies, the mobile
communication systems have reached a stage capable of providing
high-speed data communication services as well as voice
communication services. Recently, the next-generation mobile
communication systems have evolved into Human to Machine (H2M)
communication and Machine to Machine (M2M) communication, beyond
Human to Human (H2H) communication. In order to meet such a
requirement, the 3rd Generation Partnership Project (3GPP), which
is responsible for the standardization of communication, is working
on a standard for machine-type communication. In a 3GPP System
Aspects Working Group 1 (SA1) Working Group (WG) standard, which
defines services and the characteristics thereof, service
requirements for machine-type communication is already being
discussed.
[0004] FIG. 1 illustrates a communication scenario in machine-type
communication. Machine-type communication devices 105 are connected
to a wireless operator's network 110. The machine-type
communication devices 105 may be typically defined as various
unmanned devices such as meters, vending machines, or the like, and
have characteristics different in many aspects from those of the
existing wireless terminals. Also, the characteristics of the
machine-type communication devices 105 may depend on the types
thereof. One cell may include numerous machine-type communication
devices 105 which have the various characteristics as described
above. A machine-type communication server 115, which has
information on the machine-type communication devices 105, may
serve not only to perform authentication, but also to collect
pieces of information acquired from the machine-type communication
devices 105 and to deliver the collected pieces of information to a
machine-type communication user 120. The machine-type communication
server 115 may exist inside or outside the wireless operator's
network. The machine-type communication user 120 is an end user
that requires information delivered by the machine-type
communication devices 105.
[0005] The machine-type communication has characteristics different
from those of the existing wireless communication. Also, the
characteristics of the machine-type communication may be very
variously classified according to use purposes thereof. For
example, machine-type communication devices, which require
communication only a few times a day regardless of time, have a
time-tolerant characteristic, and machine-type communication
devices, which are installed at fixed positions and serve to
collect and transmit particular information without mobility, have
a low mobility characteristic. Wireless operators need to provide
services in view of such various characteristics of the
machine-type communication and the coexistence of machine-type
communication devices with the existing terminals.
[0006] Among the machine-type communication devices,
tracking-related devices, such as devices equipped on animals or
cargo vehicles, typically use batteries, or are supplied with power
generated by themselves. Accordingly, since the machine-type
communication devices need to use limited power, and it is
desirable that the machine-type communication devices efficiently
use extremely small power. The 3GPP SA1 WG defines an extra low
power consumption mode, in which machine-type communication devices
may be configured to be able to use low power. In this situation,
there is a need for a method and an apparatus for transmitting and
receiving signals to/from the machine-type communication
devices.
DETAILED DESCRIPTION OF THE INVENTION
Technical Problem
[0007] According to the above-mentioned demands, an aspect of the
present disclosure is to provide a method and an apparatus which
can more efficiently receive system information and a paging signal
of a network in a user equipment to which a longer reception cycle
is applied.
[0008] Also, another aspect of the present disclosure is to provide
a method and an apparatus which enable multiple base stations to
transmit signals to a user equipment so that the user equipment can
more efficiently receive a signal from a base station even when the
user equipment moves at a high speed within a cell that the base
station forms.
Technical Solution
[0009] In accordance with an aspect of the present disclosure, a
method for transmitting/receiving a signal by a base station of a
mobile communication system is provided. The method includes:
receiving measurement information on measurement of a neighboring
base station by a user equipment from the user equipment;
determining a higher signal transmission mode based on the received
measurement information; transmitting a request message to a small
cell base station determined based on the determined higher signal
transmission mode and the measurement information; and receiving,
from the small cell base station, at least one of an identifier for
downlink reception transmitted by the small cell and a cell
identifier of the small cell.
[0010] In accordance with another aspect of the present disclosure,
a method for transmitting/receiving a signal by a user equipment of
a mobile communication system is provided. The method includes:
transmitting, to a base station, measurement information on
measurement of a neighboring base station by the user equipment;
and receiving, from the base station, at least one of an identifier
for downlink reception from a small cell base station, which is
determined based on the measurement information, and a cell
identifier of the small cell.
[0011] In accordance with still another aspect of the present
disclosure, a method for receiving system information by a user
equipment of a mobile communication system is provided. The method
includes: receiving information related to a Discontinuous
Reception (DRX) cycle from a base station; comparing the DRX cycle
with a threshold value; and receiving modified System Information
(SI) according to a result of the comparison, wherein the receiving
of the modified SI includes receiving the modified SI according to
a received paging signal when the DRX cycle is less than the
threshold value.
[0012] In accordance with yet another aspect of the present
disclosure, a method for transmitting system information by a base
station of a mobile communication system is provided. The method
includes: transmitting information related to a Discontinuous
Reception (DRX) cycle to a user equipment; transmitting a paging
signal to the user equipment when System Information (SI) is
modified; and broadcasting the modified SI to the user equipment,
wherein the user equipment compares the DRX cycle with a threshold
value, receives the modified SI according to a result of the
comparison, and receives the modified SI according to the received
paging signal when the DRX cycle is less than the threshold
value.
Advantageous Effects
[0013] An embodiment of the present disclosure can provide the user
equipment, to which a longer reception cycle is applied and which
efficiently receives one or more of system information and a paging
signal of a base station network and thereby can have higher power
efficiency, and the controlling method thereof.
[0014] Also, another embodiment of the present disclosure can
provide the apparatus which enables a user equipment having high
mobility to easily receive a signal from a base station, and the
method for controlling the same.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a view for explaining a communication scenario in
machine-type communication;
[0016] FIG. 2 is a view for conceptually explaining a paging time
point in Long Term Evolution (LTE) technology;
[0017] FIG. 3 is a view for explaining a process in which, when a
very long DRX cycle is applied, whether System Information (SI) is
modified may not be identified and the current SI may not be
updated to new SI;
[0018] FIG. 4 is a view for explaining a method for extending a
modification period so as to enable paging to be received although
a very long DRX cycle is applied;
[0019] FIG. 5 is a view for explaining a method in which a user
equipment wakes up immediately before a DRX timing and identifies
cell (re)selection and whether SI is modified;
[0020] FIG. 6 is a view for explaining a scheme in which, according
to a DRX cycle applied in the present disclosure, selective use is
made of a method (Alternative 1) for extending a modification
period and a method (Alternative 2) for allowing a user equipment
to wake up immediately before a DRX timing and to identify cell
(re)selection and whether SI is modified;
[0021] FIG. 7 is a view for explaining a case where paging
reception fails at a DRX timing;
[0022] FIG. 8 is a view for explaining a method for solving a delay
problem when paging fails;
[0023] FIG. 9 is a view for explaining a process for receiving
paging when a very long DRX cycle is applied in the present
disclosure;
[0024] FIG. 10 is a view for conceptually explaining a Radio
Resource Control (RRC) diversity technique;
[0025] FIG. 11 is a view for explaining a process for performing
downlink (DL) RRC diversity in an embodiment of the present
disclosure;
[0026] FIG. 12 is a view for explaining an operation of a user
equipment in a process for performing DL RRC diversity;
[0027] FIG. 13 is a view for explaining an operation of a Master
Evolved Node B (MeNB) in a process for performing DL RRC
diversity;
[0028] FIG. 14 is a view for explaining an operation of a Secondary
Evolved Node B (SeNB) in a process for performing DL RRC
diversity;
[0029] FIG. 15 is a view for explaining a process for performing
uplink (UL) RRC diversity in an embodiment of the present
disclosure;
[0030] FIG. 16 is a block diagram illustrating an internal
configuration of a user equipment to which the present disclosure
is applied; and
[0031] FIG. 17 is a block diagram illustrating a configuration of a
base station according to the present disclosure.
MODE FOR CARRYING OUT THE INVENTION
[0032] Hereinafter, embodiments of the present disclosure will be
described in detail with reference to the accompanying
drawings.
[0033] In describing the exemplary embodiments of the present
invention, descriptions related to technical contents which are
well-known in the art to which the present invention pertains, and
are not directly associated with the present invention, will be
omitted. Such an omission of unnecessary descriptions is intended
to prevent obscuring of the main idea of the present invention and
more clearly transfer the main idea.
[0034] For the same reason, in the accompanying drawings, some
elements may be exaggerated, omitted, or schematically illustrated.
Further, the size of each element does not entirely reflect the
actual size. In the drawings, identical or corresponding elements
are provided with identical reference numerals.
[0035] Embodiments of the present disclosure relate to a method and
an apparatus for effectively acquiring SI and paging when a very
long DRX cycle is applied in a mobile communication system. More
particularly, embodiments of the present disclosure may be applied
to an LTE-based mobile communication system.
[0036] A user equipment in the form of a machine-type communication
device needs to minimize power consumption. The present disclosure
proposes a method in which a user equipment effectively acquires SI
and paging broadcasted by a base station when a very long DRX cycle
is applied in order to improve power consumption.
[0037] Also, embodiments of the present disclosure include
configurations of the method and the apparatus for effectively
acquiring SI and paging when a very long DRX cycle is applied in a
mobile communication system. A user equipment in the form of a
machine-type communication device needs to minimize power
consumption. The present disclosure proposes the method in which
the user equipment effectively acquires SI and paging broadcasted
by the base station when a very long DRX cycle is applied in order
to improve power consumption.
Embodiment 1
[0038] One of methods capable of improving a power consumption
problem in a user equipment of a mobile communication system is a
method for increasing a DRX cycle.
[0039] The user equipment may perform a reception operation in
order to receive a paging signal from a base station. However, a
paging signal is not frequently transmitted, and thus the power
loss of the user equipment may increase when the user equipment
performs a reception operation even for a time period during which
the paging signal is not transmitted.
[0040] Accordingly, in order to reduce power consumption of the
user equipment, the user equipment may attempt to receive a paging
signal by periodically performing an operation of receiving the
paging signal only during a particular time period. This
configuration is referred to as "DRX." In an LTE system, DRX
operations of user equipments, which are in a standby state, may be
achieved as defined by Equation 1 below. A System Frame Number
(SFN) increases by 1 on a per-radio frame basis. When a paging
signal is delivered in a radio frame satisfying Equation 1 below,
the user equipment performs a reception operation according to
DRX.
SFN mod T=(T div N)*(UE_ID mod N) Equation 1
[0041] In Equation 1,
[0042] SFN: System Frame Number. 10 bits (Most Significant Bit
(MSB) 8 bits are explicit, and Least Significant Bit (LSB) 2 bits
are implicit.)
[0043] T: DRX cycle of the User Equipment (UE). Transmitted on
SIB2. ENUMERATED {rf32, rf64, rf128, rf256}
[0044] N: min(T,nB)
[0045] nB: Transmitted on SIB2. ENUMERATED {4T, 2T, T, T/2, T/4,
T/8, T/16, T/32}.
[0046] UE_ID: IMSI mod 1024 (International Mobile Station Identity
(IMSI) is a unique number assigned to each UE)
[0047] Eight bits in a MasterinformationBlock (MIB) of a Physical
Broadcast CHannel (PBCH) represent an SFN. T and nB are values
provided by a base station in a state of being included in a
SystemInformationBlockType2 (SIB2). T may have one value from among
{rf32, rf64, rf128, rf256}, and r32 represents the length of a 32
radio frame. Specifically, r32 may signify 320 ms.
[0048] FIG. 2 conceptually illustrates a paging time point in LTE
technology.
[0049] Referring to FIG. 2, an SFN may increase by 1 on a per-radio
frame basis as indicated by reference numeral 205. The SFN has a
value which is reset to zero in a cycle of 1024 as indicated by
reference numeral 210. As defined by Equation 1, paging of an
identical pattern is repeated in each SFN cycle as indicated by
reference numeral 215. It can be noted from Equation 1 that a
maximum DRX cycle in the current LTE standard is equal to 2.56
seconds and may not exceed the cycle (i.e., 10.24 seconds) of the
SFN even when the DRX cycle is increased to a maximum.
[0050] In other words, in order to reduce power consumption, the
DRX cycle needs to be increased by 10.24 seconds or more, and the
SFN cycle also needs to be increased. In the present disclosure, in
order to increase the SFN cycle, an additional SFN bit may be
included in an existing or new System Information Block (SIB), and
an operation of the UE for receiving the SIB including the
additional SFN bit may be defined.
[0051] The SFN bits are characterized as increasing by 1 in each
SFN cycle. Also, the SFN bits are characterized in that all UEs do
not need to receive an SIB including the SFN bits and only a UE, to
which a very long DRX cycle is applied, attempts to receive the SIB
including the SFN bits. Further, a systemInfoValueTag value (one
Information Element (IE) included in SIB1), which conventionally
increases by 1 whenever SIB information is modified, and a
systemInfoModification IE, which is included in paging and notifies
of whether SI is modified, are not affected by a change in the
value of the SFN bits. Specifically, even when the value of the SFN
bits is changed, the systemInfoValueTag IE is not updated, and the
systemInfoModification IE is not transmitted through paging.
[0052] When the DRX cycle is increased together with the
above-described extension of the SFN cycle, a case occurs in which
a process of identifying whether SI is modified and updating the
current SI may not be performed.
[0053] FIG. 3 is a view for explaining a process in which, when a
very long DRX cycle is applied, whether SI is modified may not be
identified and the current SI may not be updated to new SI.
[0054] Referring to FIG. 3, in an embodiment of the present
disclosure, the UE may identify a paging signal in a very long DRX
cycle 320.
[0055] The base station may notify the UE that SI is soon to be
modified, by using paging 305 before modification of SI as
indicated by reference numeral 310. Such an operation may be
performed with a modification period 300 as a reference.
[0056] Specifically, during the modification period before the
modification of the SI, the base station notifies the UE that the
SI is to be modified in the next modification period, by using
paging. Accordingly, the UE may receive paging at least once during
the modification period, and may identify whether SI is to be
modified in the next modification period.
[0057] The UE identifies paging in each DRX cycle, and thus may
miss the transmitted paging as indicated by reference numeral 315
when the paging is transmitted during the very long DRX cycle
320.
[0058] In order to solve the above-described problem, an embodiment
of the present disclosure introduces a method for extending a
modification period and a method in which the UE wakes up
immediately before a DRX timing and identifies cell (re)selection
and whether SI is modified, and proposes a method for selectively
applying the two methods according to a particular condition in
view of advantages and disadvantages of the two methods.
[0059] FIG. 4 is a view for explaining a method for extending a
modification period so as to enable paging to be received although
a very long DRX cycle is applied.
[0060] Referring to FIG. 4, a modification period is extended so
that at least one DRX timing may be included in one modification
period 400. At this time, paging 405 notifying of a change in SI
may be transmitted during the extended modification period, and the
UE may receive the paging 405 at least once as indicated by
reference numeral 410.
[0061] The value of the modification period is provided to the UE
through SIB2. However, the modification period also needs to be
extended as a DRX cycle becomes longer, and thus a disadvantage may
occur in that signaling overhead due to the transmission of paging
increases during this time period. Moreover, a modification period
is identically applied to all of the UEs. Accordingly, although the
extended modification period is mainly useful only to Machine-Type
Communication (MTC) devices, all of the UEs need to apply the
extended modification period. Another disadvantage of the extended
modification period is that the UEs may receive the updated SI as
late as the extended modification period. Accordingly, in order to
solve the above-described problem, a typical UE and an MTC device
may apply different modification periods. Specifically, the base
station broadcasts two types of modification period values to the
UEs through SIB2. First, the UE applies a conventional modification
period, and each of the MTC devices applies a newly-defined
modification period. Alternatively, the new modification period for
the MTC devices may not be explicitly provided to the MTC devices
through SIB2, but the MTC devices may implicitly use a pre-agreed
fixed value, for example, 10.24 seconds. In this case, additional
signaling overhead may be reduced.
[0062] FIG. 5 is a view for explaining a method in which a UE wakes
up immediately before a DRX timing and confirms cell (re)selection
and whether SI is modified.
[0063] Referring to FIG. 5, paging 505 notifying of the
modification of SI is transmitted during one modification period
500, and the modified SI is transmitted in the next modification
period.
[0064] The UE has a very long DRX cycle 520, and thus may not
identify the paging 505 notifying of the modification of the SI.
Instead, the UE may wake up immediately before a DRX timing is
generated, and may receive the SI. More specifically, the UE
previously wakes up immediately before the DRX timing is generated,
performs a cell (re)selection operation, identifies a suitable
cell, and receives the SI from the cell. The received SI may
include one of a new SIB and an existing SIB, each of which
includes the above-described SFN bits, together with a MIB, SIB1,
SIB2, and SIB14, as indicated by reference numeral 515. Thereafter,
the UE attempts to receive paging at the DRX timing. This operation
has an advantage in that the UE surely receives the most recent
required SI, but has a disadvantage in that the burden of the UE is
increased due to the execution of the above-described operation at
each DRX timing when the DRX cycle is not a little long.
[0065] Accordingly, an embodiment of the present disclosure
proposes a scheme in which the UE selectively uses a method for
extending a modification period and a method for allowing the UE to
wake up immediately before a DRX timing and to identify cell
(re)selection and whether SI is modified, on the basis of whether
the applied DRX cycle exceeds a particular threshold value.
[0066] FIG. 6 is a view for explaining a scheme in which, according
to a DRX cycle applied in the present disclosure, selective use is
made of a method (Alternative 1) for extending a modification
period and a method (Alternative 2) for allowing a UE to wake up
immediately before a DRX timing and to confirm cell (re)selection
and whether SI is modified.
[0067] Referring to FIG. 6, in step 605, the UE may determine
whether a currently-applied DRX cycle is greater than a particular
threshold value X. The threshold value X may be a predetermined
value, or may be explicitly received from the base station. For
example, a modification period may be extended to a maximum of
10.24 seconds in the current LTE standard. Accordingly, 10.24
seconds may be determined as the threshold value X. Alternatively,
the base station may notify the UE of information on the threshold
value X through a SIB or dedicated signaling.
[0068] When the applied DRX cycle is less than the threshold value
X, in step 610, the UE attempts to receive paging at the DRX
timing. When a systemInfoModification IE included in the paging has
a value of "true," the value of "true" notifies of the modification
of the SI in the next modification period, and the UE receives new
SI in the next modification period by using the value of a
modification period acquired from SIB2.
[0069] When the applied DRX cycle is greater than the threshold
value X, in step 620, the UE may wake up immediately before the DRX
timing is generated, and may receive the SI. More specifically, the
UE may previously wake up immediately before the DRX timing is
generated, may perform a cell (re)selection operation, may identify
a suitable cell, and may receive the SI from the cell.
[0070] FIG. 7 is a view for explaining a case where paging
reception fails at a DRX timing.
[0071] Referring to FIG. 7, when the UE fails to receive paging at
a particular DRX timing as indicated by reference numeral 700, the
UE needs to wait for a very long DRX cycle until the UE attempts to
receive the next paging, as indicated by reference numeral 705.
Accordingly, in order to solve such a delay problem, the present
disclosure proposes a method for transmitting multiple pagings at a
DRX timing.
[0072] FIG. 8 is a view for explaining a method for solving a delay
problem when paging fails.
[0073] Referring to FIG. 8, when a DRX timing comes in the UE to
which a very long DRX cycle 805 is applied, paging is not
transmitted only once, but multiple pagings 800 are transmitted in
a short cycle in such a manner as to correspond to particular
number of times. When the UE only receives at least one of the
multiple pagings 800, the UE may successfully acquire paging
information, and thus can increase the probability of paging
reception. For the repeated number of times of paging transmission
and a cycle between transmissions, predetermined values may be
used, or the base station may notify the UE of the repeated number
of times of paging transmission and the cycle between transmissions
through a SIB. According to an embodiment of the present
disclosure, the multiple pagings 800 may be transmitted even to a
UE to which the very long DRX cycle 805 is not applied.
[0074] FIG. 9 is a view for explaining a process for receiving
paging when a very long DRX cycle is applied in the present
disclosure.
[0075] Referring to FIG. 9, in order to apply a very long DRX
cycle, a UE 900, a base station 905, and a Mobility Management
Entity (MME) 910 require a setting process 915 thereamong. In the
setting process 915, the base station and the MME previously share
whether the base station and the MME are capable of supporting a
very long DRX cycle. The UE sends a request for a very long DRX
cycle to the MME through an Attach or Tracking Area Update (TAU)
process. When the MME is capable of supporting the very long DRX
cycle, the MME notifies the UE that the MME is capable of
supporting the very long DRX cycle, through an Attach Accept
message. The UE disregards a cell-specific DRX value broadcasted by
the base station, and applies the requested very long DRX cycle.
The MME notifies the base station that the UE is applying the very
long DRX cycle. When the base station transmits paging, the base
station considers the very long DRX cycle. In step 920, the UE 900
may determine whether the currently-applied DRX cycle is greater
than a particular threshold value X. According to a result of
determining whether the currently-applied DRX cycle is greater than
the particular threshold value X, one method may be selected from
among the method (Alternative 1) for extending a modification
period and the method (Alternative 2) for allowing the UE 900 to
wake up immediately before a DRX timing and to identify cell
(re)selection and whether SI is modified, and the selected method
may be applied.
[0076] In order to apply the very long DRX cycle, the UE 900 needs
to receive additional SFN bits.
[0077] In step 925, the UE 900 acquires the SFN bit information
from SIBx broadcasted by the base station 905. Also, SIBx may
include the number of times of transmission of paging and cycle
information at each DRX timing. When the method (Alternative 2) has
been applied for allowing the UE 900 to wake up immediately before
a DRX timing and to identify cell (re)selection and whether SI is
modified, in step 930, the UE 900 may wake up before the DRX
timing, and may attempt to perform a cell (re)selection process and
receive the SI. At this time, for the cell (re)selection process,
the UE 900 performs cell measurement, and the cell measurement is
characterized by the determination of cell (re)selection based on
one measurement sample.
[0078] In step 935, when paging arrives at the base station 905
from the MME 910, in step 945, the base station 905 transmits
multiple pagings to the UE at a time point (a DRX timing) of paging
occasion 940. The transmission of the multiple pagings may be
performed based on the information which is set in step 925.
Embodiment 2
[0079] Embodiment 2 relates to the RRC diversity technique. The RRC
diversity refers to a technique which allows a UE to transmit and
receive identical RRC messages to/from multiple base stations and
increases the probability of successful reception of an RRC
message.
[0080] The RRC diversity may be classified into DL RRC diversity
and UL RRC diversity. In the DL RRC diversity, the UE receives an
identical RRC message from the multiple base stations. According to
an embodiment of the present disclosure, the DL RRC diversity is
effective particularly in a handover process during which a
received signal strength is unstable.
[0081] In the UL RRC diversity, the UE transmits an identical RRC
message to the multiple base stations. Also, in a cell boundary
area, the UL RRC diversity may increase the probability of
successful transmission of an RRC message.
[0082] FIG. 10 is a view for conceptually explaining an RRC
diversity technique.
[0083] Referring to FIG. 10, a UE 1000 may simultaneously receive
an RRC message including identical information from two base
stations, namely, an MeNB 1005 and an SeNB 1010.
[0084] RRC messages, which are intended to be transmitted to the UE
1000, may be exchanged through an Xn backhaul 1015 to which the
MeNB 1005 and the SeNB 1010 are connected. The two base stations
1005 and 1010 may use an identical frequency or different
frequencies.
[0085] When the UE 1000 moves from the MeNB 1005 to the SeNB 1010,
typically, the UE 1000 performs a handover process and changes a
serving cell from the MeNB 1005 to the SeNB 1010. During the
handover process, the SeNB 1010 may provide a better signal
strength than the MeNB 1005 according to a situation.
[0086] For example, when the UE 1000 moves from the MeNB 1005 to
the SeNB 1010 at a fast speed, the strength of a received signal
from the MeNB 1005 may be rapidly reduced. In contrast, the
strength of a received signal from the SeNB 1010 may become rapidly
better. With respect to the handover process, the MeNB 1005, which
is a current serving cell, transmits a HandOver (HO) command to the
UE 1000 and indicates the execution of a handover. When the
strength of a received signal from the MeNB 1005 is not good enough
and the UE 1000 cannot receive the HO command, the handover may
fail. When the SeNB 1010 also transmits an identical HO command to
the UE 1000, the probability of the success of a handover may be
improved. Typically, the UE 1000 moves to the SeNB 1010, and thus
the strength of a received signal from the SeNB 1010 may be good
enough.
[0087] Embodiment 2 proposes a specific process for performing RRC
diversity. The specific process includes information that the UE
1000, the MeNB 1005, and the SeNB 1010 need to mutually
exchange.
[0088] FIG. 11 is a view for explaining a process for performing DL
RRC diversity in an embodiment of the present disclosure.
[0089] Referring to FIG. 11, when a UE 1100 is connected to an MeNB
1105, in step 1115, the MeNB 1105 transmits capability information
of the UE 1100 to the neighboring SeNB 1110.
[0090] Alternatively, when the UE 1100 reports an Event A4 to the
MeNB through a measurement report with respect to the one
neighboring SeNB 1115 in step 1120, at this time, the MeNB 1105 may
notify the SeNB 1110 of the capability of the UE 1100. The Event A4
may include an event that the UE 1100 reports when the strength of
a signal, that the UE 1100 receives from a neighboring cell, is
greater than a particular threshold value.
[0091] When the information reported by the UE 1100 in step 1120
includes the neighboring SeNB 1110 providing a received signal
strength better than the particular threshold value, in step 1125,
the MeNB 1105 may determine whether the MeNB 1105 together with the
SeNB 1110 is to perform DL RRC diversity. The determination may
follow preset information, or may be made based on the information
reported by the UE 1100. Also, in an embodiment of the present
disclosure, a base station, which has a received signal strength
which is measured by the UE 1100 and has a value greater than a
threshold value, may be a base station other than the SeNB 1110. At
this time, the MeNB 1105 may utilize neighboring base station
information in order to determine an SeNB which is to perform DL
RRC diversity. More specifically, the MeNB 1105 may receive, from
the UE 1100, neighboring base station information on a neighboring
base station capable of transmitting, to the UE 1100, a signal
having a strength greater than the threshold value among
neighboring base stations of the UE 1100. The base station may
determine an SeNB, which is to perform DL RRC diversity, on the
basis of the received neighboring base station information. More
specifically, the base station may determine an SeNB, which is
adjacent to the neighboring base station represented by the
received neighboring base station information, as a base station to
perform DL RRC diversity.
[0092] When the DL RRC diversity is used, in step 1130, the MeNB
1105 delivers, to the SeNB 1110, setting information applied to the
UE 1100 and information including one or more of a diversity type
and a Time Division Multiplexing (TDM) pattern, which are intended
to be applied, through an Xn interface by using an RRC DIVERSITY
REQUEST message. The diversity type is information for proposing
the type of an RRC message using the DL RRC diversity. For example,
when the diversity type indicates "ALL RRC MESSAGE," the MeNB and
the SeNB may transmit all RRC messages. Alternatively, when the
diversity type indicates "HO command only," the MeNB and the SeNB
may simultaneously transmit messages according to only a HO
command.
[0093] The benefit of the DL RRC diversity may be generated in a
limited situation, such as a cell boundary area and the like, and
thus the execution of the DL RRC diversity in all situations may
increase only the degree of complexity without the benefit.
Accordingly, the above-described case may be controlled through the
diversity type. Alternatively, both the MeNB 1105 and the SeNB 1110
may be limited to transmit the HO command only during a situation
(i.e., a handover process) in which the benefit of the DL RRC
diversity can be maximized without diversity type information.
[0094] Also, the TDM pattern may be applied when the MeNB 1105 and
the SeNB 1110 use an identical frequency. In the above-described
situation, signals, that the MeNB 1105 and the SeNB 1110 transmit,
may cause interference with each other. Accordingly, when the UE
1100 uses different time periods in order to receive RRC messages
from the two base stations, the probability of successful
receptions of the RRC messages can be improved. As an example, the
MeNB 1105 transmits the message to the UE 1100 during a time period
from T1 to T2, and then the SeNB 1110 transmits the identical
message to the UE 1100 during a time period from T2 to T3. In order
to perform the above-described transmissions between which a time
difference exists, the UE, the MeNB 1105, and the SeNB 1110 may
previously agree on the use of radio resources thereamong.
[0095] In step 1135, the SeNB 1110 may deliver an RRC DIVERSITY
RESPONSE message to the MeNB 1105 through the Xn interface. The RRC
DIVERSITY RESPONSE message includes information which is required
for the UE 1100 to receive a message from the SeNB 1110. The
required information may include one or more of a Cell Radio
Network Temporary Identifier (C-RNTI) and a cell ID (Physical Cell
Identifier (PCI) or E-UTRAN Cell Global Identifier (ECGI)). The
C-RNTI is a kind of ID information used when the UE identifies
scheduling information thereof over a Physical Downlink Control
CHannel (PDCCH).
[0096] In step 1140, the MeNB 1105 may transmit an
RRCConnectionReconfiguration message the UE 1100. The RRC message
is used to set DL RRC diversity for the UE 1100, and includes one
or more of a C-RNTI of the SeNB 1110, an RCI/ECGI, a diversity
type, and a TDM pattern. In an embodiment of the present
disclosure, although the UE 1100 has received the
RRCConnectionReconfiguration message, the UE 1100 or the base
station may not immediately perform DL RRC diversity. For example,
when the Diversity type is "HO command only" and a handover process
is imminent, the UE 1100 or the base station may perform the DL RRC
diversity. In contrast, when the diversity type indicates "ALL RRC
MESSAGE," after the UE 1100 receives the
RRCConnectionReconfiguration message, the UE 1100 and the base
station may immediately begin to perform the DL RRC diversity. This
is because the UE 1100 does not know a time point of the
transmission of and the type of an RRC message to be transmitted to
the UE. In Embodiment 2, for convenience of description, a case is
considered in which the diversity type is "HO command only."
[0097] In step 1145, the UE 1100 reports, to the MeNB 1105, an
Event A3 measurement report on the SeNB 1110. An Event A3 includes
a case in which a signal of a neighboring cell, that the UE 1100
has measured, is larger by a particular offset value or more than a
signal of the current serving cell. A handover is triggered with
reference to the Event A3.
[0098] Accordingly, since the UE 1100, which has reported the Event
A3, may expect that the handover is soon to be performed, in step
1150, the UE 1100 begins to perform the DL RRC diversity.
[0099] In steps 1155 and 1160, the UE 1100 decodes PDCCHs from both
the MeNB 1105 and the SeNB 1110, and determines whether an RRC
message thereof is transmitted. When an identical frequency is
used, the UE 1100 may decode the PDCCHs according to the given TDM
pattern. When the PDCCHs are decoded, the UE 1100 uses the
respective C-RNTIs of the MeNB 1105 and the SeNB 1110.
[0100] In step 1165, the MeNB 1105, which has received the Event A3
reported by the UE 1100, determines a handover to the SeNB
1110.
[0101] In step 1170, the MeNB 1105 triggers the handover to the
SeNB 1110 by using a HO REQUEST message.
[0102] In step 1175, the SeNB 1110 transmits a HO REQUEST
ACKnowledgement (ACK) message which is a response message, to the
MeNB 1105. The HO REQUEST ACK message includes a HO command
message. The handover to the SeNB 1110 may be performed similarly
to an existing handover process. At this time, as occasion demands,
the UE 1100 may not receive a good signal strength provided by the
MeNB 1105. When the UE 1100 rapidly moves from a serving cell to a
target cell, this situation may frequently occur.
[0103] In an embodiment of the present disclosure, when the UE 1100
performs a handover to a third base station and the MeNB 1105
together with the SeNB(1110) performs the DL RRC diversity, the
MeNB 1105 may transmit a HO REQUEST message to the third base
station. Also, the MeNB 1105 may receive a HO REQUEST ACK message
from the third base station. The MeNB 1105 may deliver
handover-related information to the SeNB 1110, and the SeNB 1110
may perform the DL RRC diversity on the basis of the received
handover-related information.
[0104] In this case, in step 1186, the UE 1100 receives the signal
"out-of-sync," which represents that a service cannot be provided
by the MeNB 1105, from a physical layer. When the UE 1100 receives
the signal "out-of-sync" as many times as N310, the UE 1100
declares Radio Link Failure (RLF) with the MeNB 1105. The
declaration of RLF implies that, in step 1185, the UE 1100 has not
received the HO command transmitted by the MeNB 1105 in order to
indicate a handover.
[0105] When the DL RRC diversity is used, the MeNB 1105 may process
the HO command in step 1180, and may then deliver the processed
information to the SeNB 1110 in step 1190.
[0106] Alternatively, without performing step 1190, the SeNB 1110
may directly deliver the generated HO command to the UE 1100 in
step 1175.
[0107] In step 1191, the SeNB 1110 transmits the HO command to the
UE 1100. Since the UE 1100 is in a state where the UE 1100 does not
yet perform random access to the SeNB 1110, the UE 1100 is not
capable of transmitting Hybrid Automatic Repeat reQuest (HARQ)
feedback in UL, and the HO command from the SeNB 1110 may not use
HARQ.
[0108] Accordingly, the SeNB 1110 may not identify whether the HO
command has been successfully received by the UE. An embodiment of
the present disclosure proposes a method in which the SeNB 1110
starts one timer when the SeNB 1110 first transmits a HO command,
and the SeNB 1110 periodically retransmits the HO command until the
timer expires or the SeNB 1110 receives a random access preamble
from the UE 1100. The method can improve the rate of successful
reception of the HO command without a HARQ operation. Also, in an
embodiment of the present disclosure, in a case where the UE 1110
performs the handover to the third base station and the SeNB 1110
performs the DL RRC diversity, the SeNB 1110 may transmit the HO
command to the UE 1100 when the SeNB 1110 receives a message
representing the completion of the handover, or until a particular
timer expires.
[0109] In step 1193, when the UE 1100 receives at least one HO
command from the MeNB 1105 or the SeNB 1110, the UE 1100 performs a
handover operation to the SeNB 1110. Also, the UE 1100 may delete
all subsequently-received HO commands according to an embodiment of
the present disclosure.
[0110] In step 1194, the UE 1100 attempts random access to the SeNB
1110, and transmits an RRCConnectionReconfigurationComplete message
to the base station in step 1195.
[0111] Also, in an embodiment of the present disclosure, when the
SeNB 1110 is added to the UE 1100, RRC diversity may be performed.
More specifically, before step 1115, a connection may be
established between the UE 1100 and the SeNB 1110. In an embodiment
of the present disclosure, examples of a case where the UE 1100 is
connected to the SeNB 1110 and DL RRC diversity is performed may
include a case where DL RRC diversity is always performed if the
SeNB 1110 is added, and a case where DL RRC diversity is performed
only for a particular message (e.g., a case of a HO command) after
the SeNB 1110 is added. When the DL RRC diversity is performed in a
state of adding the SeNB 1110 as described above, HARQ may be
applied to the message transmitted in steps 1191 and 1192.
Accordingly, the SeNB 1110 may determine whether the message is
retransmitted to the UE 1100, on the basis of a HARQ result
according to the transmission of the massage to the UE 1100.
[0112] In an embodiment of the present disclosure, when the DL RRC
diversity is always performed if the SeNB 1110 is added, step 1115
may be omitted, or relevant information may be transmitted/received
through the exchange of messages, in the step of adding the SeNB
1110. Also, steps 1125, 1130, 1135, and 1140 may be omitted.
[0113] Also, in an embodiment of the present disclosure, after the
SeNB 1110 is added, when the DL RRC diversity is performed only for
a particular message (e.g., a case of a HO Command), step 1115 may
be omitted, or relevant information may be transmitted/received
through the exchange of messages, in the step of adding the SeNB
1110. Also, steps 1130, 1135, and 1140 may be omitted, or the
parameters may be transmitted in a state of omitting some of the
parameters, in steps 1130, 1135, and 1140.
[0114] FIG. 12 is a view for explaining an operation of a UE in a
process for performing DL RRC diversity.
[0115] Referring to FIG. 12, in step 1200, the UE receives an
RRCConnectionReconfiguration message.
[0116] In step 1205, the UE determines whether the message includes
information which sets DL RRC diversity.
[0117] When the DL RRC diversity is set, in step 1210, the UE may
determine whether a condition for triggering the DL RRC diversity
is satisfied. The UE may determine whether the trigger condition is
satisfied, on the basis of a diversity type.
[0118] When the condition is satisfied, in step 1215, the UE begins
to monitor PDCCHs of an MeNB and an SeNB.
[0119] In step 1220, the UE determines whether a HO command has
been received, on the basis of a result of the monitoring.
[0120] When the at least one HO command has been successfully
received, in step 1225, the UE may delete subsequently-received HO
commands. According to an embodiment of the present disclosure, an
operation of step 1225 may be selectively performed.
[0121] In step 1230, the UE may perform a handover on the basis of
the received HO command, and may attempt random access to the
SeNB.
[0122] In step 1235, the UE may transmit an
RRCConnectionReconfigurationComplete message to the SeNB, and may
complete the handover process.
[0123] FIG. 13 is a view for explaining an operation of an MeNB in
a process for performing DL RRC diversity.
[0124] Referring to FIG. 13, in step 1300, the MeNB may receive,
from the UE, a measurement report triggered by an Event A4 related
to one neighboring SeNB.
[0125] In step 1305, the MeNB may determine whether the MeNB
together with the SeNB is to use DL RRC diversity, on the basis of
the received measurement report information.
[0126] When the DL RRC diversity is used, in step 1310, the MeNB
may instruct the SeNB to set DL RRC diversity by using an RRC
DIVERSITY REQUEST message. At this time, the MeNB may include one
or more pieces of information among the pieces of information,
which are described in step 1130 illustrated in FIG. 11, in the RRC
DIVERSITY REQUEST message, and may transmit the RRC DIVERSITY
REQUEST message including the one or more pieces of
information.
[0127] In step 1315, the MeNB receives an RRC DIVERSITY RESPONSE
message from the SeNB. The message includes one or more pieces of
information among cell ID information (PCI or ECGI) of the SeNB and
a C-RNTI that the UE is to use to decode a PDCCH from the SeNB.
[0128] In step 1320, the MeNB sets DL RRC diversity for the UE by
using an RRCConnectionReconfiguration message. Also, the message
includes information required to perform the DL RRC diversity. More
specifically, the message may include one or more pieces of
information among the pieces of information transmitted in step
1140 of FIG. 11.
[0129] In step 1325, the MeNB may receive, from the UE, a
measurement report triggered by an Event A3 related to the
SeNB.
[0130] In step 1330, the MeNB determines whether the MeNB performs
a handover to the SeNB.
[0131] When it is determined that the MeNB performs the handover,
in step 1335, the MeNB transmits a HO REQUEST message to the
SeNB.
[0132] In step 1340, the MeNB receives a HO REQUEST ACK message,
which includes a HO command, from the SeNB.
[0133] In step 1345, the MeNB includes the HO command in an
RRCConnectionReconfiguration message, and transmits the
RRCConnectionReconfiguration message including the HO command to
the SeNB.
[0134] FIG. 14 is a view for explaining an operation of an SeNB in
a process for performing DL RRC diversity.
[0135] Referring to FIG. 14, in step 1400, the SeNB may receive an
RRC DIVERSITY REQUEST message, which instructs the SeNB to set DL
RRC diversity, from the MeNB.
[0136] In step 1405, the SeNB transmits an RRC DIVERSITY RESPONSE
message to the MeNB. The message includes one or more pieces of
information among cell ID information (PCI or ECGI) of the SeNB and
a C-RNTI that the UE is to use to decode a PDCCH from the SeNB.
[0137] In step 1410, the SeNB may receive a HO REQUEST message from
the MeNB.
[0138] In step 1415, the SeNB transmits a HO REQUEST ACK message,
which includes a HO command, to the MeNB.
[0139] In step 1420, the SeNB receives a HO command from the
MeNB.
[0140] In step 1425, the SeNB triggers one timer, and transmits HO
command to the UE in step 1420.
[0141] In steps 1435 and 1440, the SeNB may successfully receive a
random access preamble from the UE, or may periodically transmit a
HO command to the UE until the timer expires.
[0142] FIG. 15 is a view for explaining a process for performing UL
RRC diversity in an embodiment of the present disclosure.
[0143] Referring to FIG. 15, when a UE 1500 is connected to an MeNB
1505, in step 1515, the MeNB 1505 transmits capability information
of the UE 1500 to a neighboring SeNB 1510.
[0144] Alternatively, when the UE 1500 reports an Event A4 to the
MeNB 1505 through a measurement report with respect to the one
neighboring SeNB 1510 in step 1520, at this time, the MeNB 1505 may
notify the SeNB 1510 of the capability of the UE 1500.
[0145] When it is determined, based on the information received in
step 1520, that the neighboring SeNB 1510 exists which provides a
better received signal strength than a particular threshold value,
in step 1525, the MeNB 1505 determines whether the MeNB 1505
together with the SeNB 1510 is to perform UL RRC diversity.
[0146] When the UL RRC diversity is used, in step 1530, the MeNB
1505 delivers setting information applied to the UE 1500 and
information including one or more of a diversity type and a TDM
pattern, which are intended to be applied, to the SeNB 1510 through
an Xn interface by using an RRC DIVERSITY REQUEST message.
According to an embodiment of the present disclosure, a diversity
type in UL may be used to indicate a particular UL RRC message,
namely, a measurement report, a scheduling request, or the
like.
[0147] In step 1535, the SeNB 1510 delivers an RRC DIVERSITY
RESPONSE message to the MeNB 1505 through the Xn interface. The RRC
DIVERSITY RESPONSE message includes information required for the UE
1500 to receive a message from the SeNB 1510. Specifically, the
information may include one or more of a C-RNTI, a cell ID (PCI or
ECGI), a random access preamble, and a Random Access CHannel (RACH)
configuration. An embodiment of the present disclosure proposes a
method in which the UE 1500 utilizes a RACH process to transmit an
RRC message to the SeNB 1510.
[0148] Accordingly, to this end, the SeNB 1510 needs to previously
deliver, to the UE 1500, RACH-related information, namely, a
dedicated Random Access (RA) preamble to be used by the UE 1500 and
a RACH configuration.
[0149] In step 1540, the MeNB 1505 may transmit an
RRCConnectionReconfiguration message to the UE 1500. The RRC
message is used to set UL RRC diversity for the UE 1500, and also
includes one or more of a C-RNTI of the SeNB 1510, an RCI/ECGI, a
diversity type, a TDM pattern, an RA preamble, and a RACH
configuration.
[0150] Although the UE 1500 has received the
RRCConnectionReconfiguration message, the UE 1500 and the base
station may not immediately perform UL RRC diversity. For example,
when the diversity type is "Measurement Report (MR) only" and one
measurement report is triggered, the UE 1500 and the base station
may begin to perform the UL RRC diversity. In the description of
Embodiment 2, a case is considered in which the diversity type is
"MR only."
[0151] In step 1545, the UE 1500 triggers one measurement
report.
[0152] In step 1550, the UE 1500 begins to perform the UL RRC
diversity.
[0153] In step 1155, the UE 1500 may transmit a measurement report
to the MeNB 1505.
[0154] Then, in step 1160, the UE 1500 attempts RA to the SeNB
1510. In an embodiment of the present disclosure, in order to
transmit the measurement report to the SeNB 1510, first, RA needs
to be performed for UL synchronization. At this time, use may be
made of a dedicated RA preamble provided by the SeNB 1510.
[0155] In step 1565, the SeNB 1510 transmits a Random Access
Response (RAR) message to the UE 1500, and the RAR message includes
UL scheduling information (UL grant) required to transmit the
measurement report.
[0156] In step 1570, the UE 1500 transmits the measurement report
to the base station by using the UL grant information.
[0157] FIG. 16 is a block diagram illustrating an internal
configuration of a UE to which the present disclosure is
applied.
[0158] Referring to FIG. 16, the UE transmits and receives data and
the like to/from a higher layer 1610, and transmits and receives
control messages through a control message processing unit 1615.
Also, when the UE transmits a control signal or data to a base
station, according to the control of the control unit 1620, the UE
multiplexes the control signal or data through a multiplexing unit
1605, and then transmits the multiplexed control signal or data
through a transmitter 1600. In contrast, when the UE receives a
physical signal, according to the control of the control unit 1620,
the UE receives the physical signal through a receiver 1600,
demultiplexes the received signal through a demultiplexing unit
1605, and delivers the demultiplexed signal to the higher layer
1610 or the control message processing unit 1615 according to
message information.
[0159] FIG. 17 is a block diagram illustrating a configuration of a
base station according to the present disclosure.
[0160] Referring to FIG. 17, the base station device includes a
transmission/reception unit 1705, a control unit 1710, a
multiplexing/demultiplexing unit 1720, a control message processing
unit 1735, various higher layer processing units 1725 and 1730, and
a scheduler 1715. The transmission/reception unit 1705 transmits
data and a predetermined control signal through a DL carrier and
receives data and a predetermined control signal through a UL
carrier. When multiple carriers are configured, the
transmission/reception unit 1705 transmits and receives data and
control signals through the multiple carriers. The
multiplexing/demultiplexing unit 1720 serves to multiplex data
generated by the higher layer processing units 1725 and 1730 or the
control message processing unit 1735, or serves to demultiplex data
provided by the transmission/reception unit 1705 and to deliver the
demultiplexed data to the appropriate higher layer processing units
1725 and 1730, the control message processing unit 1735, or the
control unit 1710.
[0161] Although exemplary embodiments of the present invention have
been shown and described in this specification and the drawings,
they are used in general sense in order to easily explain technical
contents of the present invention, and to help comprehension of the
present invention, and are not intended to limit the scope of the
present invention. It is obvious to those skilled in the art to
which the present invention pertains that other modified
embodiments on the basis of the spirits of the present invention
besides the embodiments disclosed herein can be carried out.
* * * * *