U.S. patent application number 15/324012 was filed with the patent office on 2017-07-20 for user equipment, mobile communication system, and deactivation timer control method.
This patent application is currently assigned to NTT DOCOMO, INC.. The applicant listed for this patent is NTT DOCOMO, INC.. Invention is credited to Wuri Andarmawanti Hapsari, Hideaki Takahashi, Tooru Uchino.
Application Number | 20170208579 15/324012 |
Document ID | / |
Family ID | 55078493 |
Filed Date | 2017-07-20 |
United States Patent
Application |
20170208579 |
Kind Code |
A1 |
Uchino; Tooru ; et
al. |
July 20, 2017 |
USER EQUIPMENT, MOBILE COMMUNICATION SYSTEM, AND DEACTIVATION TIMER
CONTROL METHOD
Abstract
User equipment that executes carrier aggregation includes a
controller that executes timer control for deactivating a cell used
for the carrier aggregation, based on expiration of a timer; and a
receiver that receives, from the base station, setting information
including a timer value of the timer used in the controller,
wherein, when the setting information including a common timer
value that is common for multiple cells used for the carrier
aggregation and an individual timer value that is specified for
each cell is received, the controller executes the timer control by
applying the individual timer value to the specified cell, and when
another cell is used for which no individual timer value is
specified, the timer control is executed by applying the common
timer value.
Inventors: |
Uchino; Tooru; (Tokyo,
JP) ; Takahashi; Hideaki; (Tokyo, JP) ;
Hapsari; Wuri Andarmawanti; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NTT DOCOMO, INC. |
Tokyo |
|
JP |
|
|
Assignee: |
NTT DOCOMO, INC.
Tokyo
JP
|
Family ID: |
55078493 |
Appl. No.: |
15/324012 |
Filed: |
July 13, 2015 |
PCT Filed: |
July 13, 2015 |
PCT NO: |
PCT/JP2015/070071 |
371 Date: |
January 5, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02D 70/1264 20180101;
H04W 88/085 20130101; H04W 76/38 20180201; H04W 72/048 20130101;
Y02D 70/1262 20180101; H04W 52/0216 20130101; H04W 52/0206
20130101; H04W 72/0453 20130101; H04L 69/28 20130101; H04L 67/303
20130101; H04L 67/325 20130101; H04W 76/34 20180201; Y02D 30/70
20200801; H04W 52/0209 20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04; H04W 52/02 20060101 H04W052/02; H04L 29/06 20060101
H04L029/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 15, 2014 |
JP |
2014-145397 |
Claims
1. User equipment of a mobile communication system in which
communication is performed between the user equipment and a base
station by carrier aggregation, the user equipment comprising: a
controller that executes timer control for deactivating a cell used
for the carrier aggregation, based on expiration of a timer; and a
receiver that receives, from the base station, setting information
including a timer value of the timer used in the controller,
wherein, when the receiver receives the setting information
including a common timer value that is common for multiple cells
used for the carrier aggregation and an individual timer value that
is specified for each cell, the controller executes the timer
control by applying the individual timer value to the specified
cell, and when another cell is used for which no individual timer
value is specified, the controller executes the timer control by
applying the common timer value to the other cell.
2. The user equipment according to claim 1, wherein, when the
receiver receives, from the base station, setting information
including the common timer value and not including the individual
timer value, the controller executes the timer control by applying
the common timer value to each cell.
3. The user equipment according to claim 1, wherein, when the
receiver receives an update instruction for the individual timer
value from the base station, the controller restarts a timer of a
cell that is a target of the individual timer value, and applies
the updated individual timer value.
4. The user equipment according to claim 1, wherein, when the
receiver receives an update instruction for the individual timer
from the base station, the controller deactivates or deletes a cell
that is a target of the individual timer value; and, upon detecting
that the cell is activated, the controller applies the individual
timer value of the update instruction to the cell.
5. The user equipment according to claim 1, wherein, when the
receiver receives setting information including the common timer
value and one or more individual time values, the controller
compares the individual timer values with the common timer value;
and, upon detecting that there exists an individual timer value
that matches the common timer value, the controller determines that
there is a failure in the setting information.
6. The user equipment according to claim 1, wherein the controller
transmits, to the base station, capability information indicating
that the user equipment is able to apply the individual timer
value.
7. The user equipment according to claim 1, wherein the cell that
is a target of the timer control is an SCell.
8. A mobile communication system including user equipment and a
base station that perform carrier aggregation, wherein the user
equipment comprises: a controller that executes timer control for
deactivating a cell used for the carrier aggregation, based on
expiration of a timer; and a receiver that receives, from the base
station, setting information including a timer value of the timer
used in the controller, wherein the base station comprises: a
transmitter that transmits, to the user equipment, the setting
information including a common timer value that is common for
multiple cells used for the carrier aggregation, or the setting
information including both the common timer value and an individual
timer value specified for each cell, wherein, when the user
equipment receives, by the receiver, the setting information
including the common timer value and the individual timer value,
the user equipment executes, by the controller, the timer control
by applying the individual timer value to the specified cell, and
when another cell is used for which no individual timer value is
specified, the user equipment executes, by the controller, the
timer control by applying the common timer value to the other
cell.
9. A deactivation timer control method to be executed by user
equipment of a mobile communication system in which communication
is performed between the user equipment and a base station by
carrier aggregation, the deactivation timer control method
comprising: a receiving step of receiving, from the base station,
setting information including a timer value of a timer that is used
for timer control for deactivating a cell used for the carrier
aggregation, based on expiration of the timer; and a controlling
step of executing the timer control, wherein, when the user
equipment receives, in the receiving step, the setting information
including a common timer value that is common for multiple cells
used for the carrier aggregation, and an individual timer value
that is specified for each cell, the user equipment executes, in
the controlling step, the timer control by applying the individual
timer value to the specified cell, and when another cell is used
for which no individual timer value is specified, the user
equipment executes, in the controlling step, the timer control by
applying the common timer value to the other cell.
Description
TECHNICAL FIELD
[0001] The present invention relates to a mobile communication
system, and especially related to deactivation control of a SCell
in carrier aggregation.
BACKGROUND ART
[0002] For the LTE-Advanced, carrier aggregation (CA: Carrier
Aggregation) has been adopted in which communication is performed
by simultaneously using a plurality of carriers while using
bandwidths supported by the LTE (up to 20 MHz) as basic units, so
that throughput can be achieved that exceeds that of the LTE, while
maintaining backward compatibility with the LTE (cf. Non-Patent
Document 1, for example). A carrier that can be a basic unit in the
carrier aggregation is referred to as a component carrier (CC:
Component Carrier).
[0003] When the CA is performed, a PCell (Primary cell), which is a
highly reliable cell for ensuring connectivity, and a SCell
(Secondary cell), which is a subsidiary cell, are established for
user equipment UE. First, the user equipment UE connects to the
PCell; and can add the SCell, depending on necessity. The PCell is
the same as a cell of the LTE scheme that supports the RLM (Radio
Link Monitoring), the SPS (Semi-Persistent Scheduling), and so
forth.
[0004] The SCell is established for the user equipment UE, in
addition to the PCell. Addition and deletion of the SCell are
performed through the RRC (Radio Resource Control) signaling. The
SCell is in a deactivated state (deactivate state) immediately
after it is established for the user equipment UE, so that it is a
cell in which communication is enabled (scheduling is enabled) only
after it is activated in the MAC (Media Access Control) layer. For
the SCell, activation/deactivation is controlled by a MAC signal
from the base station eNB.
[0005] Note that, for TDD, the PCell is formed of a single CC; and
for FDD, the PCell is formed of an uplink CC and a downlink CC.
Further, for TDD, the SCell is formed of a single CC; and for FDD,
the SCell is formed of a downlink CC (and an uplink CC, depending
on necessity). Furthermore, there are cases where the "cell," such
as the PCell and the SCell, is used as a synonym of the CC.
PRIOR ART DOCUMENT
Non-Patent Document
[0006] Non-Patent Document 1: 3GPP TS 36.300 V12.1.0 (2014-03)
[0007] Non-Patent Document 2: 3GPP TS 36.331 V12.1.0 (2014-03)
[0008] Non-Patent Document 3: 3GPP TS 36.321 V10.10.0 (2013-12)
[0009] Non-Patent Document 4: 3GPP TSG-RAN WG2 #86 19-23 May 2014
R2-142483
SUMMARY OF INVENTION
Problem to be Solved by the Invention
[0010] For the LTE, by a SCell deactivation timer
(sCellDeactivationTimer, which is referred to the "deactivation
timer" or the "timer," hereinafter), control is performed for
deactivating the SCell (cf. Non-Patent Documents 2 and 3).
Basically, when the SCell is activated, upon receiving the PDCCH
(downlink or uplink resource allocation), the user equipment UE
restarts the deactivation timer associated with the SCell; and
performs control for deactivating the SCell, if the deactivation
timer expires without receiving a PDCCH.
[0011] For the CA according to up to Rel-11 of the LTE, since a
value of the deactivation timer can be set in units of user
equipment UEs, a single setting value is applied to all the SCells.
These specifications are specified on the assumption that the timer
value is determined by a traffic characteristic of a service (e.g.,
inter-packet arrival time). However, for a case where the timer
value of the deactivation timer is set in units of user equipment
UEs (i.e., common for the SCells), there is a problem as described
below.
[0012] FIG. 1 is a diagram illustrating a system configuration,
which can be the assumption for describing the problem. As
illustrated in FIG. 1, in the system, the base station eNB forms,
in each of three directions, a PCell and a SCell #1, as macro
cells; and CA is further configured by forming a SCell #2, which is
a small cell, by a RRH (Remote Radio Head) that is extended from a
base station eNB (HetNet scenario).
[0013] FIG. 2 and FIG. 3 are diagrams illustrating the problem for
the case where, in the configuration of FIG. 1, the same timer
values are applied to all the SCells. FIG. 2 illustrates an example
of a case where the timer value is small; and FIG. 3 illustrates an
example of a case where the timer value is large.
[0014] As illustrated in FIG. 2, for the case where the timer value
is small, after receiving, by the user equipment UE, PDCCHs in the
SCell #1 and the SCell #2, respectively, the timer expires in a
short time, and the SCell #1 and the SCell #2 are deactivated. In
this case, the base station eNB immediately becomes unable to
schedule, so that response is degraded due to delay, and an effect
of off-loading to the small cell is also reduced. However, there is
an advantage that a battery saving effect is large in the user
equipment UE. As illustrated in FIG. 3, for the case where the
timer value is large, opportunities for the base station eNB to
schedule are increased, so that response is enhanced, and the
effect of off-loading to the small cell is enlarged. However, a
problem is that battery energy consumption is enlarged in the user
equipment UE.
[0015] Consequently, it has been studied to allow, in Rel-12, timer
values to be individually set to the SCells (cf. Non-Patent
Document 4).
[0016] However, for allowing the timer values to be individually
set to the SCells, it is not clear as to how signaling is to be
performed in the RRC; and if a configuration is adopted that merely
allows individual setting, backward compatibility may not be
ensured. For example, since the user equipment UE is unable to
recognize the release (the Release number) of the base station eNB,
even if individual timer values are expected for the SCells, the
base station eNB actually supports only up to Rel-11, so that the
timer value for each user equipment UE (the timer values common for
the SCells) might have been notified. In such a case, the user
equipment UE may not properly set the timer value, and the
deactivation timer control of the SCells may not be properly
performed, so that battery energy waste may occur, for example.
[0017] The present invention has been achieved in view of the
above-described point, and an object is to provide a technique that
allows deactivation timer control to be properly performed for a
case of setting cell individual timer values for a mobile
communication system, in which, for the deactivation timer control
of cells for carrier aggregation, a timer value is to be set that
is common for the cells.
Means for Solving the Problem
[0018] According to an embodiment of the present invention, there
is provided user equipment of a mobile communication system in
which communication is performed between the user equipment and a
base station by carrier aggregation, the user equipment including a
controller that executes timer control for deactivating a cell used
for the carrier aggregation, based on expiration of a timer; and a
receiver that receives, from the base station, setting information
including a timer value of the timer used in the controller,
wherein, when the receiver receives the setting information
including a common timer value that is common for multiple cells
used for the carrier aggregation and an individual timer value that
is specified for each cell, the controller executes the timer
control by applying the individual timer value to the specified
cell, and when another cell is used for which no individual timer
value is specified, the controller executes the timer control by
applying the common timer value to the other cell.
[0019] Further, according to an embodiment of the present
invention, there is provided a mobile communication system
including user equipment and a base station that perform carrier
aggregation, wherein the user equipment includes a controller that
executes timer control for deactivating a cell used for the carrier
aggregation, based on expiration of a timer; and a receiver that
receives, from the base station, setting information including a
timer value of the timer used in the controller, wherein the base
station includes a transmitter that transmits, to the user
equipment, the setting information including a common timer value
that is common for multiple cells used for the carrier aggregation,
or the setting information including both the common timer value
and an individual timer value specified for each cell, wherein,
when the user equipment receives, by the receiver, the setting
information including the common timer value and the individual
timer value, the user equipment executes, by the controller, the
timer control by applying the individual timer value to the
specified cell, and when another cell is used for which no
individual timer value is specified, the user equipment executes,
by the controller, the timer control by applying the common timer
value to the other cell.
[0020] Furthermore, according to an embodiment of the present
invention, there is provided a deactivation timer control method to
be executed by user equipment of a mobile communication system in
which communication is performed between the user equipment and a
base station by carrier aggregation, the deactivation timer control
method including a receiving step of receiving, from the base
station, setting information including a timer value of a timer
that is used for timer control for deactivating a cell used for the
carrier aggregation, based on expiration of the timer; and a
controlling step of executing the timer control, wherein, when the
user equipment receives, in the receiving step, the setting
information including a common timer value that is common for
multiple cells used for the carrier aggregation, and an individual
timer value that is specified for each cell, the user equipment
executes, in the controlling step, the timer control by applying
the individual timer value to the specified cell, and when another
cell is used for which no individual timer value is specified, the
user equipment executes, in the controlling step, the timer control
by applying the common timer value to the other cell.
Advantage of the Invention
[0021] According to an embodiment of the present invention, in a
mobile communication system, in which, for deactivation timer
control of cells for carrier aggregation, a timer value is to be
set that is common for the cells, the deactivation timer control
can be properly performed, even for a case of setting cell
individual timer values.
BRIEF DESCRIPTION OF DRAWINGS
[0022] FIG. 1 is a system configuration diagram that can be an
assumption for describing a problem;
[0023] FIG. 2 is a diagram illustrating an operation related to a
sCellDeactivationTimer (a short case) in units of UEs;
[0024] FIG. 3 is a diagram illustrating the operation related to
the sCellDeactivationTimer (a long case) in units of UEs;
[0025] FIG. 4 is a configuration diagram of a communication system
according to an embodiment of the present invention;
[0026] FIG. 5 is a diagram illustrating operation example 1 of the
communication system in the embodiment of the present
invention;
[0027] FIG. 6 is a diagram illustrating an example of timer control
for a case where an individual timer value is applied;
[0028] FIG. 7 is a diagram illustrating operation example 2 of the
communication system in the embodiment of the present
invention;
[0029] FIG. 8 is a diagram illustrating operation example 3 of the
communication system in the embodiment of the present
invention;
[0030] FIG. 9 is a diagram illustrating operation example 4 of the
communication system in the embodiment of the present
invention;
[0031] FIG. 10 is a diagram illustrating an operation example for a
case where setting of the individual timer value is to be
changed;
[0032] FIG. 11A is a diagram illustrating an example of a RRC
message provided with individual timer information;
[0033] FIG. 11B is a diagram illustrating an example of the RRC
message provided with the individual timer information;
[0034] FIG. 12 is a configuration diagram of user equipment UE;
[0035] FIG. 13 is a configuration diagram of a base station eNB;
and
[0036] FIG. 14 is a flowchart illustrating an operation example of
the user equipment UE.
EMBODIMENTS OF THE INVENTION
[0037] An embodiment of the present invention is described below by
referring to the drawings. Note that the embodiment described below
is merely an example, and embodiments to which the present
invention is applied are not limited to the embodiment below. For
example, in the embodiment, the target of the deactivation timer
control is the SCell; however, the target of the deactivation timer
control may be another type of a cell (e.g., PCell). Further, in
the embodiment, the LTE mobile communication system is the target;
however, the present invention is not limited to the LTE, and it
can be applied to another mobile communication system. Furthermore,
in the present specification and the scope of the claims, the term
"LTE" is used in a sense to include schemes of Rel-12, or on and
after Rel-12 of the 3GPP, unless as indicated otherwise.
[0038] (Overall Configuration of the System, and Overview of the
Operation)
[0039] FIG. 4 illustrates a configuration diagram of a
communication system in the embodiment of the present invention. As
illustrated in FIG. 4, the communication system in the embodiment
is a system including a base station eNB and user equipment UE. In
FIG. 4, one base station eNB and one user equipment UE are
illustrated; however, it is for convenience of depiction, and
plural of these may be included.
[0040] Further, in the example of FIG. 4, the base station eNB
itself is provided with a radio unit; and, at the same time, a
radio unit (RRH) is installed at a location separated from the base
station eNB. The radio unit is a part of the base station eNB; and
it is connected to the base station eNB through an optical fiber,
for example. In the embodiment, similar to the scenario illustrated
in FIG. 1, CA can be achieved by the PCell and the SCell.
Hereinafter, a timer value in units of user equipment, which has
been used in related art, is referred to as a common timer value
(which means that it is common for SCells within one UE); and a
timer value that is to be set in units of SCells is referred to as
an individual timer value.
[0041] In the embodiment, a signaling configuration is achieved
that allows, while maintaining backward compatibility, setting of
SCell individual timer values.
[0042] Namely, in the embodiment, it is assumed that, first, the
base station eNB reports, by RRC signaling, the individual timer
value to the user equipment UE depending on necessity, in addition
to the common timer value.
[0043] For example, "depending on necessity" means that a case is
assumed in which the base station eNB attempts to transfer
(offload) traffic from a SCell of a macro cell to a SCell of a
small cell, so that it is desirable to set an individual timer
value of the SCell of the macro cell to be small, and to set an
individual timer value of the SCell of the small cell to be large.
If it is not in such a situation, and if setting of an individual
timer value is not necessary, only the common timer value may be
reported.
[0044] Furthermore, related to "depending on necessity," in the
embodiment, the base station eNB can determine whether the user
equipment UE supports individual timer values by capability
information, such as the release number, reported from the user
equipment UE to the base station eNB; and, upon determining that
the user equipment UE does not support the individual timer values,
the base station eNB may not report the individual timer values to
the user equipment UE.
[0045] Furthermore, the individual timer value is to be set to the
SCell individually, and it is necessary to specify the target
SCell, so that, for reporting an individual timer value, the base
station eNB reports, as a set, the individual timer value together
with identification number (index) of the target SCell. Here, the
identification number can be any number, provided that the SCell
can be identified with the number; and, for example, a Cell Index
of the SCell (an identification number of a Cell, which includes
the PCell) may be used. Hereinafter, a set of an individual timer
value and a SCell identification number is referred to as
individual timer information. For a case where the "individual
timer information" is related to a plurality of SCells, the
"individual timer information" includes a plurality of the
above-described sets, such as (SCell 1, timer value 1), (SCell 2,
timer value 2), and so forth.
[0046] For user equipment UE that supports the individual timer
value (which can execute timer control to which the individual
timer value is applied), the base station eNB recognizes it, as
described above. When the base station eNB transmits, to the user
equipment UE, a common timer value and individual timer information
by RRC signaling, the user equipment UE that receives these applies
the individual timer value to the SCell specified by the individual
timer information, and executes deactivation control by the
individual timer value for the SCell. For the SCell that is not
specified by the individual timer information, the user equipment
UE executes deactivation control by applying the common timer
value.
[0047] The base station eNB supporting the individual timer value
recognizes whether the user equipment UE supports the individual
timer value, so that the base station eNB can maintain timers that
are synchronized with respective SCell timers that operate in each
user equipment UE; can recognize an activated state/deactivated
state of the SCell in the user equipment UE; and can properly
perform scheduling, for example.
[0048] Furthermore, in the embodiment, the base station eNB not
supporting the individual timer value can perform operations with
the user equipment UE supporting the individual timer value, based
on the common timer value, which is the same as that of related
art.
Operation Example
[0049] Some operation examples of the communication system
according to the embodiment are described below by referring to the
sequence diagrams. In each of the following examples, the base
station supporting the individual timer value (which can report the
individual timer value) can recognize whether the user equipment UE
supports the individual timer value, so that the corresponding
operation can be performed. In contrast, it is assumed that the
base station that does not support the individual timer value
performs the operation where the user equipment UE is assumed to
support only the common timer value. Additionally, it is assumed
that the user equipment UE may not recognize whether the base
station eNB supports the individual timer value.
[0050] Further, transmission and reception of signals in the
following operation examples are performed with RRC messages;
however, it is not limited to this, and it may be performed with
another message (e.g., MAC signals). Furthermore, the following
examples illustrate only main signals related to the embodiment;
and signals for activation and so forth are not depicted.
Operation Example 1
[0051] First, operation example 1 is described by referring to FIG.
5. Operation example 1 is an example for a case where the user
equipment UE supports the individual timer value, and the base
station eNB also supports the individual timer value.
[0052] In response to transmitting, by the base station eNB, an
instruction to add a SCell to the user equipment UE (step 101), one
or more SCells are established for the user equipment UE, and, at
the same time, the base station eNB transmits, to the user
equipment UE, a common timer value and the individual timer
information (step S102). In FIG. 5, step 102 is performed after
step 101; however, these may be simultaneously performed.
[0053] The user equipment UE executes, for the SCell specified by
the individual timer information, deactivation timer control by
performing control, such as activation of the timer, monitoring of
the PDCCH, and monitoring of expiration of the timer, by applying
the specified individual timer value (step 103). Additionally, for
a case where, among the plurality of active SCells, there is a
SCell that is not specified by the individual timer information,
the user equipment UE executes deactivation timer control by
applying the common timer value to that SCell.
[0054] For both cases of the individual and common, for example,
upon receiving, for each of the SCells, an activation signal or a
PDCCH (resource allocation), the user equipment UE starts or
restarts (restart) the corresponding timer; and, upon detecting
that the timer expires (the time period of the timer value elapses)
without receiving an activation signal or a PDCCH, the user
equipment UE deactivates the corresponding active SCell.
[0055] FIG. 6 illustrates an example of timer control operation for
a case where the individual timer value is applied. FIG. 6 shows a
case of CA, which is formed of the PCell, the SCell #1, and the
SCell #2; and, similar to FIG. 1, the PCell and the SCell #1
correspond to macro cells, and the SCell #2 corresponds to a small
cell. Furthermore, the individual timer value corresponding to the
SCell #1 is smaller than the individual timer value corresponding
to the SCell #2.
[0056] In this case, scheduling opportunities increase for the
small cell, so that offloading gain can be increased, and the
response is enhanced. Furthermore, the macro cell (SCell #1) is
deactivated at an earlier stage, so that a battery saving effect is
obtained, compared to a case where both SCells are continued to be
active.
Operation Example 2
[0057] Next, operation example 2 is described by referring to FIG.
7. The operation example 2 is an example of a case where the user
equipment UE does not support the individual timer value, and the
base station eNB supports the individual timer value.
[0058] In response to transmitting, by the base station eNB, an
instruction to add a SCell to the user equipment UE (step 201), one
or more SCells are established for the user equipment UE, and, at
the same time, the base station eNB transmits, to the user
equipment UE, a common timer value (step S202). The user equipment
UE executes, for each of the SCells, deactivation timer control by
applying the common timer value (step 203).
[0059] In this example, the base station eNB transmits only the
common timer value because the base station eNB recognizes that the
user equipment UE does not support the individual timer value;
however, if the base station eNB may not determine whether the user
equipment UE supports the individual timer value, the base station
eNB may transmit both common timer value and individual timer
information. In this case, since the user equipment UE does not
support the individual timer value, the user equipment UE ignores
the information element indicating the individual timer value; and
executes control that is the same as that of related art where only
the common timer value is used. For a case of such control, for
example, it can be considered to transmit, from the user equipment
UE to the base station eNB, a signal indicating that the user
equipment UE only uses the common timer value. Consequently, the
base station eNB can recognize that only the common time value is
used in the user equipment UE; and can execute
deactivation/activation state management, which is synchronized
with the user equipment UE.
Operation Example 3
[0060] Next, operation example 3 is described by referring to FIG.
8. The operation example 3 is an example of a case where the user
equipment UE supports the individual timer value, and the base
station eNB does not support the individual timer value.
[0061] In response to transmitting, by the base station eNB, an
instruction to add a SCell to the user equipment UE (step 301), one
or more SCells are established for the user equipment UE, and, at
the same time, the base station eNB transmits, to the user
equipment UE, a common timer value (step S302).
[0062] Though the user equipment supports the individual timer
value, since no individual timer information is received from the
base station eNB, the user equipment UE executes, for each of the
SCells, deactivation timer control by applying the common timer
value (step 303).
[0063] As described above, according to the embodiment, operation
can be properly performed for each of the cases where the
individual timer value is supported/not supported in the user
equipment UE and the base station eNB. Namely, the individual timer
value can be set, while maintaining backward compatibility.
Operation Example 4
[0064] Next, operation example 4 is described by referring to FIG.
9. In the operation example 4, the user equipment UE is a UE based
on a specification of a release that does not specify the
individual timer value; however, the user equipment UE includes, as
a function of the UE, a function for supporting the individual
timer value (Early implementation). Further, the base station eNB
supports the individual timer value. In this example, the user
equipment UE reports, to the base station eNB, the release
information that does not specify the individual timer value, so
that the base station eNB determines that the user equipment UE
does not support the individual timer value.
[0065] Accordingly, in this example, as illustrated in FIG. 9, the
user equipment UE transmits, to the base station eNB, capability
information indicating that the individual timer value is
supported, separately from the release information (step 401). The
capability information may be transmitted, for example, by the RRC
message at the time of RRC connection; or may be transmitted by
another signal at another timing.
[0066] The base station eNB that receives the capability
information can recognize that the user equipment UE supports the
individual timer value, so that the common timer value and the
individual timer information can be transmitted, similar to the
case of FIG. 5 (step 402). Then, similar to the case of FIG. 5, the
user equipment UE executes deactivation timer control for the SCell
specified by the individual timer information by applying the
individual timer value (step 403); and, additionally, for a case
where, among the plurality of active SCells, there is a SCell that
is not specified by the individual timer information, the user
equipment UE executes deactivation timer control by applying the
common timer value to that SCell.
[0067] Here, as the capability information in the operation example
4, information may be reported that indicates that the UE is
provided with capability for supporting the individual timer value;
or information may be reported that indicates, for each band
combination (a band combination of CCs with which CA can be
performed), whether there is capability for supporting the
individual timer value. Furthermore, for a case of the user
equipment UE that supports Dual Connectivity, information may be
reported that indicates, for each eNB (MeNB, SeNB), or for each CG
(Cell Group), whether there is capability for supporting the
individual timer value.
Operation Example for Changing Setting of the Individual Timer
Value (Operation Example 5)
[0068] Next, by referring to FIG. 10, an operation example is
described for a case where setting of the individual timer value is
to be changed. In the embodiment, for each SCell, a timer value can
be set depending on a condition of the network or on a traffic
condition, so that a timer value may be changed for an active SCell
by a determination by the base station eNB. In such a case, for
example, a difference in recognition of timer values may occur in
such a manner that, even if it is maintained, at the side of the
base station eNB, that the user equipment UE uses the updated timer
value B for the SCell 1, the user equipment UE is actually using,
for the SCell 1, the timer value A prior to the update.
[0069] Thus, in operation example 5, in order to eliminate the
difference in recognition of the timer values as much as possible,
for example, as illustrated in FIG. 10, upon transmitting a timer
value update instruction (step 501) from the base station eNB to
the user equipment UE (in the example of FIG. 10, the timer value
of the SCell 1 is updated), the user equipment UE restarts
(restart) the timer of the SCell 1 corresponding to the update
instruction, and executes expiration management of the restarted
timer with the updated timer value (step 502).
[0070] In addition to the above-described operation, during
transmission of the instruction to update the timer value of the
SCell 1, the SCell may be deactivated by a command from the base
station eNB. Further, instead of a command from the base station
eNB, upon receiving the timer value update instruction, the user
equipment UE may deactivate the SCell. After that, the base station
eNB activates the SCell depending on necessity; and the user
equipment UE applies a new timer value from that moment.
Additionally, during updating the timer value, the SCell may be
deleted, and a SCell may be newly added. Upon the added SCell being
activated, the updated timer value is applied.
[0071] Note that operation example 4 and operation example 5 can be
implemented in combination with another operation example. Further,
related to all operation examples of the embodiment, in the user
equipment UE that supports the individual timer value, if the
individual timer information is not sent from the base station eNB
during a time of handover or a time of reconfiguration
(reconfiguration), the common timer value may be used.
[0072] Further, the base station eNB may report only the individual
timer value which value is different from the common timer value.
Namely, the base station eNB may report the individual timer
information to the SCell only if a timer value that is different
from the common timer value is set.
[0073] Then, for a case where the individual timer information is
reported from the base station eNB to the user equipment UE
together with the common timer value, the user equipment UE
compares each individual timer value included in the individual
timer information with the common timer value, and if there is an
individual timer value which value is the same as the common timer
value, the user equipment UE may determine that there is an
abnormality (failure) in the RRC signaling signal (e.g., RRC
reconfiguration).
[0074] (Examples of the Message)
[0075] FIG. 11A illustrates the MAC-MainConfig information element
(an extract), which is an example of an information element of the
RRC message including the individual timer information. In FIG.
11A, information of the DedicatedsCellDeactivationTimer corresponds
to the individual timer information according to the embodiment.
FIG. 11B is an example of the MAC-MainConfig field descriptions (an
extract) in the form published in the specification of the LTE. In
FIG. 11B, in addition to the description of the
DedicatedsCellDeactivationTimer, which corresponds to the
embodiment, the description of the existing sCellDeactivationTimer
is also shown.
[0076] (Examples of the Device Configurations)
[0077] Next, examples of the device configurations of the user
equipment UE and the base station eNB are described, which can
perform the above-described operations.
[0078] <User Equipment UE>
[0079] FIG. 12 illustrates a functional configuration diagram of
the user equipment UE according to the embodiment of the present
invention. As illustrated in FIG. 12, the user equipment UE
includes a DL signal receiver 101; a UL signal transmitter 102; an
operation controller 103; a CA state manager 104; and a timer
manager 105. Note that FIG. 12 only illustrates the functional
units that are particularly relevant to the present invention in
the user equipment UE; and the user equipment UE also includes, at
least, functions, which are not depicted, for performing the
operation conforming to the LTE.
[0080] The DL signal receiver 101 includes a function for receiving
various types of downlink signals from the base station eNB, and
for retrieving more upper layer information from the received
physical layer signals; and the UL signal transmitter 102 includes
a function for generating various types of physical layer signals
from upper layer information to be transmitted from the user
equipment UE, and for transmitting these to the base station eNB.
Furthermore, the DL signal receiver 101 and the UL signal
transmitter 102 respectively include functions for executing
communication through CA, for which a plurality of CCs (PCell,
SCell) are utilized. Note that, the CA (carrier aggregation) in the
embodiment includes, not only the Intra-eNB CA, but also the
Inter-eNB CA (namely, Dual Connectivity).
[0081] As described above, the operation controller 103 implements
setting of timer values, updating the setting, and addition and
deletion of the SCell, which are based on the RRC signaling; and
activation/deactivation control, timer control, and CA operation
control, and so forth, which are based on the MAC signals.
Furthermore, for a case where setting information is received from
the base station eNB, which includes a common timer value that is
common among a plurality of SCells and individual timer values
which are specified for respective SCells, the operation controller
103 applies the individual timer values to the specified cells, and
executes timer control; and, at the same time, for a case where a
SCell is used for which no individual timer is specified, the
operation controller 103 executes timer control by applying the
common timer value to the SCell.
[0082] The latest information of the CA state (e.g., information of
the established SCell, activated/deactivated information for each
SCell) is stored in the CA state manager 104, and it is referred to
by the operation controller 103. The timer manager 105 executes,
for each SCell, activation (restart) of a timer based on a common
timer value or an individual timer value based on an instruction
from the operation controller 103; and finds whether each timer has
expired. When the timer expires, it is reported to the operation
controller 103.
[0083] <Base Station eNB>
[0084] FIG. 13 illustrates a functional configuration diagram of
the base station eNB according to the embodiment of the present
invention. As illustrated in FIG. 13, the base station eNB includes
a DL signal transmitter 201; a UL signal receiver 202; a CA
controller 203; and a UE state manager 204. Note that FIG. 13 only
illustrates the functional units that are particularly relevant to
the present invention in the base station eNB; and the base station
eNB also includes, at least, functions, which are not depicted, for
performing the operation conforming to the LTE.
[0085] The DL signal transmitter 201 includes a function for
generating various types of physical layer signals from upper layer
information to be transmitted from the base station eNB, and for
transmitting them. The UL signal receiver 202 includes a function
for receiving various types of uplink signals from the user
equipment UE, and for retrieving more upper layer information from
the received physical layer signals. Furthermore, the DL signal
transmitter 201 and the UL signal receiver 202 respectively include
functions for executing communication by CA, for which a plurality
of CCs (PCell, SCell) are utilized.
[0086] The CA controller 203 in the embodiment includes a function
for generating RRC signaling information including a common timer
value and an individual timer information, which are described
above, based on information stored in the UE state manager 204, and
for transmitting it from the DL signal transmitter 201; a function
for generating an activating/deactivating signal, and for
transmitting it from the DL signal transmitter 201, and so forth.
Further, the CA controller 203 includes a function for
transmitting, to the user equipment UE, setting information
including a common timer value that is common for a plurality of
SCells, or setting information including both the common timer
value and an individual timer value that is specified for each
SCell, based on the capability information of the user equipment
UE, for example.
[0087] The UE state manager 204 receives the above-described
capability information from each UE and stores it; and, at the same
time, manages, for each UE, a state of each SCell (e.g., an
activated/deactivated state, a state of the timer).
[0088] The operations of the user equipment UE and the base station
eNB are as described as operation examples 1 through 5, and so
forth; and FIG. 14 illustrates an example of a timer value setting
operation and control operation in the user equipment UE. As
illustrated in FIG. 14, the operation controller 103 of the user
equipment UE adds an SCell based on the RRC signaling from the base
station eNB (step 601). In this operation example, the RRC
signaling includes information on a timer.
[0089] The operation controller 103 checks whether individual timer
information is included in the information received through the RRC
signaling (step 602); if it exists (Yes at step 602), the process
proceeds to step 603; and if it does not exist (No at step 602),
the process proceeds to step 604.
[0090] At step 603, the operation controller 103 implements
deactivation timer control by applying the individual timer value
to the SCell that is specified by the individual timer information.
Furthermore, the operation controller 103 implements the
deactivation timer control by applying the common timer value to
the active SCells that are not specified by the individual timer
information. At step 604, the operation controller 103 implements
deactivation timer control by applying the common timer value to
each of the SCells.
Conclusions of the Embodiment, and Effects, etc.
[0091] According to the embodiment of the present invention, there
is provided user equipment of a mobile communication system in
which communication is performed between the user equipment and a
base station by carrier aggregation, the user equipment including a
controller that executes timer control for deactivating a cell used
for the carrier aggregation, based on expiration of a timer; and a
receiver that receives, from the base station, setting information
including a timer value of the timer used in the controller,
wherein, when the receiver receives the setting information
including a common timer value that is common for a plurality of
cells used for the carrier aggregation and an individual timer
value that is specified for each cell, the controller executes the
timer control by applying the individual timer value to the
specified cell, and when another cell is used for which no
individual timer value is specified, the controller executes the
timer control by applying the common timer value to the other
cell.
[0092] With this configuration, in a mobile communication system,
in which, a timer value is to be set that is common for the cells,
the deactivation timer control can be properly performed, even for
a case of setting cell individual timer values.
[0093] When the receiver receives, from the base station, setting
information including the common timer value and not including the
individual timer value, the controller may execute the timer
control by applying the common timer value to each cell. With this
configuration, the user equipment can properly execute the
deactivation timer control, even for a case where it is to be
connected to a base station that does not support the individual
timer value.
[0094] When the receiver receives an update instruction for the
individual timer value from the base station, the controller may
restart a timer of a cell that is a target of the individual timer
value, and may apply the updated individual timer value. With this
configuration, the update of the individual timer value in the base
station can be quickly reflected to the user equipment, so that
occurrence of a difference between the timer values can be
suppressed.
[0095] When the receiver receives an update instruction for the
individual timer from the base station, the controller may
deactivate or delete a cell that is a target of the individual
timer value; and, upon detecting that the cell is activated, the
controller may apply the individual timer value of the update
instruction to the cell. With this configuration, a difference of
the timer values for the deactivation control can be prevented from
occurring, between the base station and the user equipment.
[0096] When the receiver receives setting information including the
common timer value and one or more individual time values, the
controller may compare the individual timer values with the common
timer value; and, upon detecting that there exists an individual
timer value that matches the common timer value, the controller may
determine that there is a failure in the setting information. With
this configuration, for a case where the base station is to report
only the individual timer values that are different from the common
timer value, a failure in the setting information can be
detected.
[0097] The controller may transmit, to the base station, capability
information indicating that the user equipment is able to apply the
individual timer value. With this configuration, the base station
can find that the user equipment supports the control by the
individual timer value, and reporting of the individual timer value
can be properly performed.
[0098] A cell that is a target of the timer control may be an
SCell. With this configuration, deactivation control suitable for
the LTE can be performed.
[0099] The functional configuration of the user equipment UE
described in the embodiment may be a configuration that is
implemented by executing a program by the CPU (processor) in the
user equipment including the CPU and the memory; a configuration
that is implemented by hardware provided with a logic for the
process described in the embodiment, such as a hardware circuit; or
a mixture of programs and hardware.
[0100] The functional configuration of the base station described
in the embodiment may be a configuration that is implemented by
executing a program by the CPU (processor) in the base station
including the CPU and the memory; a configuration that is
implemented by hardware provided with a logic for the process
described in the embodiment, such as a hardware circuit; or a
mixture of programs and hardware.
[0101] The embodiment of the present invention is described above;
however the disclosed invention is not limited to the embodiment,
and a person ordinarily skilled in the art will appreciate various
variations, modifications, alternatives, replacements, and so
forth. Specific examples of numerical values are used in the
description in order to facilitate understanding of the invention.
However, these numerical values are merely an example, and any
other appropriate values may be used, except as indicated
otherwise. The separations of the items in the above description
are not essential to the present invention. Depending on necessity,
subject matter described in two or more items may be combined and
used, and subject matter described in an item may be applied to
subject matter described in another item (provided that they do not
contradict). A boundary of a functional unit or a processor in the
functional block diagrams may not necessarily correspond to a
boundary of a physical component. An operation by a plurality of
functional units may be physically executed by a single component,
or an operation of a single functional unit may be physically
executed by a plurality of components. For the convenience of
description, the user equipment and the base station are described
by using the functional block diagrams; however, such devices may
be implemented in hardware, software, or combinations thereof. Each
of the software programs to be executed by the processor included
in the user equipment and the software programs to be executed by
the processor included in the base station eNB in accordance with
the embodiment of the present invention may be stored in any
appropriate storage medium, such as a random access memory (RAM), a
flash memory, a read-only memory (ROM), an EPROM, an EEPROM, a
register, a hard disk drive (HDD), a removable disk, a CD-ROM, a
database, a server, and so forth.
[0102] The present invention is not limited to the above-described
embodiment; and various variations, modifications, alternatives,
replacements, and so forth are included in the present invention
without departing from the spirit of the present invention.
[0103] This patent application is based upon and claims the benefit
of priority of Japanese Patent Application No. 2014-145397 filed on
Jul. 15, 2014, and the entire contents of Japanese Patent
Application No. 2014-145397 are incorporated herein by
reference.
LIST OF REFERENCE SYMBOLS
[0104] eNB: base station [0105] UE: user equipment [0106] 101: DL
signal receiver [0107] 102: UL signal transmitter [0108] 103:
Operation controller [0109] 104: CA state manager [0110] 105: timer
manager [0111] 201: DL signal transmitter [0112] 202: UL signal
receiver [0113] 203: CA controller [0114] 204: UE state manager
* * * * *