JP6200200B2 - Radio base station and mobile communication method - Google Patents

Description

  The present invention relates to a radio base station and a mobile communication method.

  In the LTE (Long Term Evolution) method, “DRX (Distinuous Reception) control” is adopted for the purpose of battery saving of the mobile station UE.

  The DRX control is configured to manage the mobile station UE in the RRC_Connected state in two states, “Active state” and “Inactive state”.

  Here, the mobile station UE in the “Active state” is configured to monitor PDCCH (Physical Downlink Control Channel) and report feedback information (CQI / PMI / RI / PTI, etc.) to the radio base station eNB. Has been.

  On the other hand, the mobile station UE in the “Inactive state” is configured not to monitor the PDCCH and not to report feedback information (CQI / PMI / RI / PTI etc.) to the radio base station eNB for battery saving. Has been.

  Here, the mobile station UE is configured to be in the “Active state” when the following conditions are satisfied, and in the “Inactive state” otherwise.

-When "On duration Timer", "drx-Inactivity Timer", "drx-Retransmission Timer", or "mac-contention Resolution Timer" is activated
-When "Scheduling request" is sent
-When “UL grant” for “UL HARQ retransmission” is assigned
-When "Random Access Response" is received and then a PDCCH signal instructing new transmission has not been received For example, as shown in FIG. 7, the mobile station UE in "Active state" has "drx-Inactivity Timer" Is configured to transition to an “Inactive state”.

  Alternatively, as shown in FIG. 8, the mobile station UE in the “Active state” may receive a “DRX command MAC CE (Control Element) from the radio base station eNB even when“ drx-Inactivity Timer ”is activated. ”Is received, the“ drx-Inactivity Timer ”is forcibly stopped and a transition to the“ Inactive state ”is made.

  In addition, a case where “Periodic TA (Timing Advance)” is used as one of operation modes using DRX control is known.

  As illustrated in FIG. 9, in such a case, the radio base station eNB manages “TIT (Traffic Inactivity Timer)” for the mobile station UE, and while the “TIT” is activated, the non-DRX It is configured to transmit “Periodic TA” to the mobile station UE in a state with a predetermined period.

  The radio base station eNB restarts “TIT” when it detects data to be transmitted / received to / from the mobile station UE in the non-DRX state, and transmits “Periodic TA” when “TIT” expires. It is configured to stop and transition to the DRX state when “drx-Inactivity Timer” expires.

  That is, the mobile station UE in the non-DRX state has a period corresponding to the sum of “TIT” and “drx-Inactivity Timer” even after there is no more data to be transmitted from the radio base station eNB to the mobile station UE. Until the time elapses, the non-DRX state is maintained, the arrival of data in such a period can be awaited, and the data transmission / reception restart delay can be reduced.

3GPP TS36.321 v11.1.0

  However, as shown in FIG. 10, the mobile station UE in the DRX state performs RRC (Radio Resource) performed at the time of report of “Measurement Report (MR)” or setting or releasing of Scell in “Carrier Aggregation (CA)”. At the time of occurrence of an RRC procedure such as a (Control) procedure, the U-plane data to be transmitted / received with respect to the mobile station UE is transitioned to a non-DRX state, which is not preferable from the viewpoint of battery saving. was there.

  Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a radio base station and a mobile communication method capable of performing appropriate DRX control from the viewpoint of battery saving in a mobile station. .

  A first feature of the present invention is a radio base station, a timer management unit configured to manage a first timer and a second timer for a mobile station, and the first timer is activated A transmission unit configured to transmit a timing adjustment command to the mobile station in a non-discontinuous reception state at a predetermined period, and the timer management unit is in a non-discontinuous reception state. When the data to be transmitted / received with respect to the mobile station is detected, the first timer is configured to be started or restarted, and the timer management unit generates control data related to the mobile station in an intermittent reception state. In this case, the second timer is configured to start or restart, and the timer management unit is configured to stop the first timer when the second timer expires. Need it To.

  According to a second aspect of the present invention, there is provided a mobile communication method, in which a radio base station performs a non-discontinuous reception state on a mobile station in a predetermined cycle while the first timer for the mobile station is activated. A step of transmitting a timing adjustment command; a step of starting or restarting the first timer when the wireless base station detects data to be transmitted / received with respect to the mobile station in a non-discontinuous reception state; When the base station generates control data related to the mobile station in the intermittent reception state, the step of starting or restarting the second timer, the radio base station, when the second timer expires, A step of stopping the first timer, and a step of transitioning to the intermittent reception state when the mobile station in the non-intermittent reception state does not receive data for a predetermined period after the last data reception. To do.

  A third feature of the present invention is a radio base station, which is configured to manage a first timer and a second timer for a mobile station, and a value of the first timer is a predetermined value. A transmission unit configured to transmit a timing adjustment command in a predetermined cycle when the value is smaller than the threshold, and to stop transmitting the timing adjustment command when the value of the first timer exceeds the predetermined threshold; The value of the first timer is configured to increase as time elapses, and the timer management unit detects data to be transmitted / received with respect to the mobile station in a non-discontinuous reception state. The first timer is stopped at the time, and “TIT” is started when there is no data to be transmitted / received with respect to the mobile station in the non-discontinuous reception state. The control unit is configured to start or restart the second timer when control data related to the mobile station is generated, and the timer management unit is configured to start the first timer when the second timer expires. The gist is that the timer is configured to stop.

  As described above, according to the present invention, it is possible to provide a radio base station and a mobile communication method capable of performing appropriate DRX control from the viewpoint of battery saving in a mobile station.

1 is an overall configuration diagram of a mobile communication system according to a first embodiment of the present invention. FIG. 3 is a functional block diagram of a radio base station eNB according to the first embodiment of the present invention. It is a figure for demonstrating operation | movement of the mobile communication system which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the radio base station eNB which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the radio base station which concerns on the example of a change of this invention. It is a figure for demonstrating the radio base station which concerns on the example of a change of this invention. It is a figure for demonstrating a prior art. It is a figure for demonstrating a prior art. It is a figure for demonstrating a prior art. It is a figure for demonstrating a prior art.

(Mobile communication system according to the first embodiment of the present invention)
A mobile communication system according to a first embodiment of the present invention will be described with reference to FIGS.

  The mobile communication system according to the present embodiment is a mobile communication system to which the LTE scheme is applied, and includes a radio base station eNB and a mobile station UE as shown in FIG.

  As illustrated in FIG. 2, the radio base station eNB according to the present embodiment includes a timer management unit 11 and a transmission unit 12.

  The timer management unit 11 is configured to manage “TIT”, “TIT stop Timer”, and the like.

  The transmission unit 12 is configured to transmit various signals to the mobile station UE. For example, as illustrated in FIG. 3, the transmission unit 12 transmits, to the mobile station UE in the non-DRX state, at a predetermined period while “TIT” managed by the timer management unit 11 is activated. “Periodic TA” is transmitted.

  The timer management unit 11 is configured to start or restart “TIT” when data to be transmitted / received regarding the mobile station UE in the non-DRX state is detected.

  Further, when SRB (Signaling Radio Bearer) data (uplink data or downlink data) related to the mobile station UE in the DRX state is generated, as shown in FIG. The “TIT stop Timer” managed as is started or restarted.

  For example, as illustrated in FIG. 3, when the “TIT stop Timer” expires, the timer management unit 11 stops “TIT”, and thus the transmission unit 12 stops transmission of “Periodic TA”. As a result, the “drx-Inactivity Timer” managed in the mobile station UE expires, and the mobile station UE in the non-DRX state transitions to the DRX state.

  Here, the transmission unit 12 is configured to transmit “DRX command MAC CE” instructing the mobile station UE to transition to the DRX state when “TIT stop Timer” expires. Also good.

  For example, the transmission unit 12 may be configured to multiplex with the last SRB data (for example, RLC-ACK for “RRC connection reconfiguration complete”) and transmit “DRX command MAC CE”.

  In addition, when the U-plane data to be transmitted with respect to the mobile station UE in the non-DRX state is generated while the “TIT stop Timer” is activated, the timer management unit 11 sets the “TIT stop Timer”. It may be configured to stop and restart “TIT”.

  Hereinafter, with reference to FIG. 4, the operation of the mobile communication system according to the present embodiment, specifically, the operation of the radio base station eNB according to the present embodiment will be described.

  As illustrated in FIG. 4, when the radio base station eNB determines in step S101 that “TIT stop Timer” has expired, the radio base station eNB stops “TIT” in step S102.

  The characteristics of the present embodiment described above may be expressed as follows.

  The first feature of the present embodiment is a radio base station eNB configured to manage “TIT (first timer)” and “TIT stop Timer (second timer)” for the mobile station UE. The “Periodic TA (timing adjustment command)” is transmitted to the mobile station UE in the non-DRX state (non-discontinuous reception state) at a predetermined cycle while “TIT” is activated The timer management unit 11 activates or restarts “TIT” when data to be transmitted / received with respect to the mobile station UE in the non-DRX state is detected. When the SRB data (control data) related to the mobile station UE in the DRX state (intermittent reception state) is generated, the timer management unit 11 performs “TIT sto “p Timer” is configured to start or restart, and the timer management unit 11 is configured to stop “TIT” when “TIT stop Timer” expires. .

  According to such a configuration, the RRC procedure for the DRX mobile station UE (the RRC procedure performed when the “Measurement Report (MR)” is reported or the Scell is set or released in the “Carrier Aggregation (CA)”) is performed. In other words, after a predetermined period has elapsed since the generation of SRB data related to the mobile station UE in the DRX state, the mobile station UE that has transitioned to the non-DRX state can transition to the DRX state again.

  In the first feature of the present embodiment, the transmission unit 12 instructs “DRX command MAC CE (instruction information) to instruct the mobile station UE to transition to the DRX state when“ TIT stop Timer ”expires. ) "May be configured to be transmitted.

  According to this configuration, the mobile station UE in the non-DRX state can be forcibly shifted to the DRX state without waiting for the expiration of the “drx-Inactivity Timer” managed in the mobile station UE.

  In the first feature of the present embodiment, the transmission unit 12 may be configured to transmit “DRX command MAC CE” multiplexed on the last SRB data.

  According to such a configuration, the mobile station UE in the non-DRX state can be forcibly shifted to the DRX state without transmitting a new signal for transmitting “DRX command MAC CE”.

  In the first feature of the present embodiment, the timer management unit 11 uses the U-plane data (user data) to be transmitted regarding the mobile station UE in the non-DRX state while the “TIT stop Timer” is activated. It may be configured to stop the “TIT stop Timer” and restart the “TIT” when the error occurs.

  According to such a configuration, when U-plane data to be transmitted regarding the mobile station UE in the non-DRX state is generated while the “TIT stop Timer” is activated, the transmission of “Periodic TA” is performed. By making it valid, the mobile station UE can remain in the non-DRX state.

  The radio base station eNB detects, for example, the arrival of downlink data from an upper node (serving gateway device S-GW) or the fact that downlink data of a predetermined threshold value or more remains in the buffer. In such a case, it is configured to detect the occurrence of U-plane data in the downlink.

  Also, the radio base station eNB receives a BSR (Buffer Status Reporting) from the mobile station UE, receives a “Scheduling Request” that is individually assigned to the mobile station UE, or U-plane When receiving “UL MAC SDU / MAC PDU” including data (or including only U-plane data), it is configured to detect that U-plane data is generated in the uplink. .

  A second feature of the present embodiment is a mobile communication method, in which the radio base station eNB transmits to the non-DRX mobile station UE at a predetermined cycle while “TIT” for the mobile station UE is activated. On the other hand, a step of transmitting “Periodic TA”, a step of starting or restarting “TIT” when the radio base station eNB detects data to be transmitted / received regarding the mobile station UE in the non-DRX state, When the radio base station eNB generates SRB data to be transmitted regarding the mobile station UE in the DRX state, the radio base station eNB starts or restarts the “TIT stop Timer”, and the radio base station eNB performs the “TIT stop Timer”. And when the mobile station UE in the non-DRX state does not receive data for a predetermined period after the last data reception. And the step of transitioning to the DRX state.

  According to such a configuration, the RRC procedure for the DRX mobile station UE (the RRC procedure performed when the “Measurement Report (MR)” is reported or the Scell is set or released in the “Carrier Aggregation (CA)”) is performed. In other words, after a predetermined period has elapsed since the generation of SRB data related to the mobile station UE in the DRX state, the mobile station UE that has transitioned to the non-DRX state can transition to the DRX state again.

  In the second feature of the present embodiment, when the radio base station eNB expires, “DRX command MAC CE” that instructs the mobile station UE to transition to the DRX state when “TIT stop Timer” expires. The mobile station UE in the non-DRX communication state may further include a step of transitioning to the DRX state in accordance with the “DRX command MAC CE”.

  According to this configuration, the mobile station UE in the non-DRX state can be forcibly shifted to the DRX state without waiting for the expiration of the “drx-Inactivity Timer” managed in the mobile station UE.

(Example of change)
In the above-described embodiment, the radio base station eNB transmits “Periodic TA” when “TIT” is activated, and “Periodic” when “TIT” is stopped (expired). The case where control for stopping the transmission of “TA” is performed has been described as an example, but the present invention can also be realized in other cases.

  For example, as illustrated in FIG. 5, the radio base station eNB transmits “Periodic TA” when the value of “TIT” (instantaneous value) is smaller than a predetermined threshold, and the value of “TIT” (instantaneous value). May exceed the predetermined threshold, transmission of “Periodic TA” may be stopped. Here, the value of “TIT” is configured to count up as time passes.

  In such a case, the radio base station eNB is configured to stop “TIT” when data to be transmitted / received is detected, and to activate “TIT” when there is no data to be transmitted / received.

  In this case, as shown in FIG. 6, the radio base station eNB sets “Periodic TA” by setting the value of “TIT” to a value larger than a predetermined threshold in accordance with the expiration of the “TIT stop Timer” described above. It may be configured to stop.

  Here, the radio base station eNB may activate the value of “TIT” using a predetermined threshold as an initial value.

  That is, the modification 1 of the present invention is characterized in that the radio base station eNB is configured to manage the “TIT” and “TIT stop Timer” for the mobile station UE, and “ When the value of “TIT” is smaller than the predetermined threshold value, “Periodic TA” is transmitted, and when the value of “TIT” exceeds the predetermined threshold value, transmission of “Periodic TA” is stopped. The value of “TIT” is configured to increase as time passes, and the timer management unit 11 should transmit and receive with respect to the mobile station UE in the non-DRX state. It is configured to stop “TIT” when data is detected, and to start “TIT” when there is no data to be transmitted / received regarding the mobile station UE in the non-DRX state The timer management unit 11 is configured to start or restart the “TIT stop Timer” when the SRB data related to the mobile station UE in the DRX state is generated. The gist is that “TIT” is set to a value larger than a predetermined threshold when “TIT stop Timer” expires.

  The operations of the mobile station UE and the radio base station eNB described above may be implemented by hardware, may be implemented by a software module executed by a processor, or may be implemented by a combination of both. .

  The software module includes a RAM (Random Access Memory), a flash memory, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electronically Erasable and Programmable ROM, a hard disk, a registerable ROM, a hard disk). Alternatively, it may be provided in a storage medium of an arbitrary format such as a CD-ROM.

  Such a storage medium is connected to the processor so that the processor can read and write information from and to the storage medium. Further, such a storage medium may be integrated in the processor. Such a storage medium and processor may be provided in the ASIC. Such an ASIC may be provided in the mobile station UE or the radio base station eNB. Further, the storage medium and the processor may be provided as a discrete component in the mobile station UE or the radio base station eNB.

  Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

eNB ... radio base station UE ... mobile station 11 ... timer manager 12 ... transmitter

Claims (5)

A wireless base station,
A timer manager configured to manage a first timer and a second timer for a mobile station;
A transmission unit configured to transmit a timing adjustment command to the mobile station in a non-discontinuous reception state at a predetermined period while the first timer is activated;
The timer management unit is configured to start or restart the first timer when detecting data to be transmitted / received with respect to the mobile station in a non-discontinuous reception state,
The timer management unit is configured to start or restart the second timer when control data related to the mobile station in an intermittent reception state is generated,
The timer management unit is configured to stop the first timer when the second timer expires ,
The timer management unit stops the second timer when the user data to be transmitted with respect to the mobile station in the non-discontinuous reception state is generated while the second timer is activated, and the first timer A radio base station configured to restart a timer .   The transmission unit is configured to transmit instruction information for instructing the mobile station to transition to an intermittent reception state when the second timer expires. The radio base station according to 1.   The radio base station according to claim 2, wherein the transmission unit is configured to transmit the instruction information multiplexed with a last control signal. A step in which the radio base station transmits a timing adjustment command to the mobile station in a non-discontinuous reception state at a predetermined period while the first timer for the mobile station is activated;
Starting or restarting the first timer when the wireless base station detects data to be transmitted / received with respect to the mobile station in a non-discontinuous reception state;
A step of starting or restarting a second timer when the radio base station generates control data related to the mobile station in an intermittent reception state;
The wireless base station, when the second timer expires, stopping the first timer;
When the radio base station generates user data to be transmitted regarding the mobile station in a non-discontinuous reception state while the second timer is running, the radio base station stops the second timer, and Restarting the timer; and
And a step of transitioning to the intermittent reception state when the mobile station in the non-intermittent reception state does not receive data for a predetermined period after the last data reception. The wireless base station, when the second timer expires, transmitting instruction information for instructing the mobile station to transition to an intermittent reception state;
The mobile communication method according to claim 4 , further comprising a step of transitioning the mobile station in a non-discontinuous reception state to an intermittent reception state in accordance with the instruction information.

Images