JP2015076847A - Wireless base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid occurrence of mismatch in the DRX state of a mobile station UE between a wireless base station eNB and the mobile station UE, even when the (Dedicated preamble) is detected erroneously in the wireless base station eNB, when the (DL data resuming)is performed.SOLUTION: In a wireless base station eNB, when DRX control is applied to a mobile station UE, a transmission unit 12 transmits the "SyncRequest" to the mobile station UE, in the "On duration" of the mobile station UE. When synchronization establishment is not successful in the uplink by the "SyncRequest", the transmission unit 12 re-transmits the "SyncRequest" a predetermined number of times, and when synchronization establishment is not successful in the uplink by the "SyncRequest" of a predetermined number of times, the transmission unit 12 re-transmits the "SyncRequest" in the "On duration" of the next mobile station UE.

Description

  The present invention relates to a radio base station.

  In the LTE (Long Term Evolution) method and the LTE-Advanced method, for the purpose of battery saving of the mobile station UE, a control (that is, DRX control) for transitioning the mobile station UE in the “RRC_Connected state” to the DRX (Discontinuous Reception) state It is defined so that it can be performed (see Patent Document 1).

  Specifically, the mobile station UE in the DRX state is configured to transition between the Active state and the Inactive state.

  Here, the mobile station UE in the active state monitors the PDCCH (physical downlink control channel) and provides feedback information to the radio base station eNB, for example, CQI (Channel Quality Indicator), PMI (Precoding Matrix Index), It is configured to report RI (Rank Indicator), PTI (Precoding Type Indicator), and the like.

  On the other hand, since the mobile station UE in the inactive state is configured not to monitor the PDCCH and report the feedback information to the radio base station eNB, battery saving of the mobile station UE can be realized.

  In any of the following cases, the mobile station UE is in the Active state, and in other cases, the mobile station UE is in the Inactive state.

-The case where "On duration timer", "drx-InactivityTimer", drx-RetransmissionTimer "or" mac-contentionResolutionTimer "is activated
-A case where a scheduling request is sent
-Case where “UL grant” for HARQ (Hybrid ARQ) retransmission in uplink is assigned
-A case where a downlink control signal instructing a new transmission is not received via the PDCCH after receiving a random access response (Random Access Response) is set to transition to the DRX state in FIG. 5 and FIG. The operation of the mobile station UE being connected is shown.

  Also, in the LTE scheme, when the radio base station eNB determines that synchronization establishment is necessary in the uplink with the mobile station UE, the “PDCCH (Physical Downlink Control) order” is used for the mobile station UE. Thus, it is assumed that an RA (Random Access) procedure activation instruction is performed (see Non-Patent Document 2). Hereinafter, such an activation instruction is referred to as “SyncRequest”.

  For example, when the radio base station eNB is out of synchronization in the uplink, or when returning from the DRX state (when “DL / UL data resuming” is performed), the radio base station eNB is in the uplink with the mobile station UE. It is configured to determine that synchronization needs to be established.

  In addition, in the LTE scheme, the radio base station eNB determines that the CRC of “UL-SCH” specified by RAR (Random Access Response) in the RA procedure activated by “Sync Request” is OK. It is conceivable that control is performed so that synchronization establishment is considered to be completed in the uplink between.

  In other cases, it is conceivable that control is performed such that the radio base station eNB considers that synchronization has not been successfully established in the uplink with the mobile station UE.

  Further, in the LTE scheme, even when the radio base station eNB transmits “Sync Request”, when synchronization in the uplink with the mobile station UE cannot be established, control is performed to retransmit “Sync Request”. It is possible.

  Here, if the uplink synchronization with the mobile station UE cannot be established even if the radio base station eNB retransmits “Sync Request” a predetermined number of times, the mobile station UE is a cell under the radio base station eNB. It is conceivable that control is performed such that the call is released autonomously assuming that it has moved outside.

3GPP TS36.321 3GPP TS36.300

  However, when “DL data resumming” is performed, if the radio base station eNB erroneously detects “Dedicated preamble”, there is a mismatch in the DRX state of the mobile station UE between the radio base station eNB and the mobile station UE. There was a problem that it occurred.

  Specifically, as illustrated in FIG. 7, in step S2001, the radio base station eNB performs “Sync Request” on the mobile station UE in a period (“On duration”) in which the mobile station UE is in the Active state. Although transmitted, the mobile station UE fails to receive the “SyncRequest”.

  Thereafter, the radio base station eNB erroneously detects “Dedicated preamble” in step S2002, and transmits a RAR to the mobile station UE in step S2003.

  Here, in step S2004, the radio base station eNB considers that the mobile station UE has received the RAR, and assumes that the mobile station UE is in the Active state.

  Thereafter, since the radio base station eNB does not detect that the CRC of “UL-SCH” specified by the RAR described above is OK, in step S2005, the radio base station eNB retransmits “Sync Request” to the mobile station UE.

  In step S2006, when the radio base station eNB retransmits “SyncRequest” a predetermined number of times to the mobile station UE, the radio base station eNB autonomously performs call release processing even though the mobile station UE is connected. End up. This is not preferable from the viewpoint of call control.

  Therefore, the present invention has been made in view of the above-described problems. Even when “Dedicated preamble” is erroneously detected in the radio base station eNB when “DL data resume” is performed, the radio An object of the present invention is to provide a radio base station eNB that can avoid the occurrence of a mismatch in the DRX state of the mobile station UE between the base station eNB and the mobile station UE.

  A first feature of the present invention is that a radio base station transmits a synchronization request to a mobile station when it is determined that synchronization needs to be established in the uplink with the mobile station. When the intermittent reception control is applied to the mobile station, the configured transmission unit and the transmission unit transmit the synchronization request to the mobile station during an ON period of the mobile station. The transmission unit is configured to retransmit a predetermined number of synchronization requests when the synchronization establishment in the uplink by the synchronization request is not successful, and the transmission unit The gist of the present invention is that the synchronization request is retransmitted in the next ON period of the mobile station when the uplink synchronization is not successfully established by a predetermined number of synchronization requests.

  As described above, according to the present invention, when "DL data resumming" is performed, even if "Dedicated preamble" is erroneously detected in the radio base station eNB, the radio base station eNB and the mobile station It is possible to provide a radio base station eNB that can avoid the occurrence of a mismatch in the DRX state of the mobile station UE with the UE.

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 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. As an example of the mobile communication system according to the present embodiment, an LTE mobile communication system will be described. However, the present invention is also applicable to mobile communication systems other than the LTE system.

  As shown in FIG. 1, the mobile communication system according to the present embodiment includes a radio base station eNB and a mobile station UE.

  In the mobile communication system according to the present embodiment, the radio base station eNB is configured to be able to transition the mobile station UE in the “RRC_Connected state” to the DRX state.

  As illustrated in FIG. 2, the radio base station eNB according to the present embodiment includes a control unit 11, a transmission unit 12, and a reception unit 13.

  The control unit 11 is configured to perform various controls (for example, DRX control) related to communication in the mobile station UE, and the transmission unit 12 is configured to transmit various signals to the mobile station UE. The receiving unit 13 is configured to receive various signals from the mobile station UE.

  Here, the transmission unit 12 is configured to transmit “SyncRequest” to the mobile station UE when it is determined that synchronization needs to be established in the uplink with the mobile station UE.

  Here, when DRX control is applied to the mobile station UE, the transmission unit 12 is configured to transmit “Sync Request” to the mobile station UE in “On duration” of the mobile station UE. Yes.

  The transmission unit 12 is configured to retransmit a predetermined number of “Sync Requests” when the uplink synchronization by the “Sync Request” is not successfully established.

  Further, the transmission unit 12 is configured to retransmit the “Sync Request” in the “On duration” of the next mobile station UE when the synchronization establishment in the uplink by the predetermined number of “Sync Request” is not successful. Yes.

  Here, the number of retransmissions to be performed after retransmission in “On duration” of the mobile station UE may be configured to be different from the above-mentioned predetermined number of times.

  Hereinafter, the operation of the mobile communication system according to the present embodiment will be described with reference to FIG. 3 and FIG. 4.

  First, referring to FIG. 3, in the mobile communication system according to the present embodiment, when synchronization is established in the uplink with the mobile station UE to which the DRX state is applied (that is, “DL data resuming”). Will be described.

  As shown in FIG. 3, in step S1001, the radio base station eNB transmits “Sync Request” to the mobile station UE during the period in which the mobile station UE is in the Active state (“On duration”). The station UE fails to receive such “SyncRequest”.

  Thereafter, the radio base station eNB erroneously detects “Dedicated preamble” in step S1002, and transmits a RAR to the mobile station UE in step S1003.

  Here, in step S1004, the radio base station eNB considers that the mobile station UE has received the RAR, and assumes that the mobile station UE is in the Active state.

  After that, since the radio base station eNB does not detect that the CRC of “UL-SCH” specified by the RAR described above is OK, in step S1005, the radio base station eNB retransmits “Sync Request” to the mobile station UE.

  When the radio base station eNB resends “Sync Request” a predetermined number of times to the mobile station UE in step S1006, in step S1007, the radio base station eNB sets “Sync Request” in “On duration” of the next mobile station UE. resend.

  2ndly, with reference to FIG. 4, operation | movement of the radio base station eNB which concerns on this embodiment is demonstrated.

  As illustrated in FIG. 4, the radio base station eNB sets “k = 0” in step S101, and in step S102, sets “Sync Request” to the mobile station UE in “On duration” of the mobile station UE. In step S103, “n = 0” is set.

  In step S104, the radio base station eNB determines whether or not the RA procedure has been completed (that is, whether or not synchronization establishment has been completed in the uplink with the mobile station UE).

  If “Yes”, the operation ends. If “No”, the operation proceeds to step S105.

  In step S105, the radio base station eNB increases “n” by one, and in step S106, determines whether “n” is smaller than “n_max”. Here, “n_max” corresponds to the predetermined number of times described above.

  If “Yes”, the operation proceeds to step S107, and if “No”, the operation proceeds to step S108.

  In step S107, the radio base station eNB transmits “Sync Request” to the mobile station UE.

  The radio base station eNB increases “k” by 1 in step S108, and determines whether “k” is smaller than “k_max” in step S109. Here, “k_max” corresponds to the number of retransmissions performed after retransmission in the “On duration” of the mobile station UE described above.

  In the case of “Yes”, the operation returns to Step S102, and in the case of “No”, the operation is terminated.

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

  The first feature of this embodiment is the radio base station eNB, and when it is determined that synchronization needs to be established in the uplink with the mobile station UE, the mobile station UE receives “SyncRequest (synchronization). The transmission unit 12 configured to transmit “request)” and the transmission unit 12, when DRX control (intermittent reception control) is applied to the mobile station UE, the “On duration ( “On period)” is configured to transmit “Sync Request” to the mobile station UE, and the transmission unit 12 is configured to perform a predetermined number of “If the synchronization establishment in the uplink by“ Sync Request ”is not successful. The transmission unit 12 is configured to retransmit the “SyncRequest”, and the transmission unit 12 performs an uplink request by a predetermined number of “SyncRequest”. If unsuccessful in establishing synchronization in click, the "On duration" of the next mobile station UE, and the gist that is configured to retransmit the "SyncRequest".

  According to this feature, in the case where “DL data resuming” is performed, if the radio base station eNB has not successfully established synchronization in the uplink by a predetermined number of times of “SyncRequest”, the “On” of the next mobile station UE Since “SyncRequest” is retransmitted in “duration”, even if “Dedicated preamble” is erroneously detected in radio base station eNB, movement between radio base station eNB and mobile station UE The occurrence of a mismatch in the DRX state of the station UE can be avoided.

  In the first feature of the present embodiment, the number of retransmissions performed after retransmission in “On duration” of the mobile station UE may be configured to be different from the predetermined number of times described above.

  According to this feature, the trade-off between the processing delay due to the retransmission of “Sync Request” in “On duration” of the mobile station UE and the occurrence of a mismatch in the DRX state of the mobile station UE between the radio base station eNB and the mobile station UE. It is possible to realize “DL data resuming” in consideration of OFF.

  Note that 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 and the radio base station eNB. Moreover, this storage medium and processor may be provided in the mobile station UE and the radio base station eNB as a discrete component.

  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.

UE ... mobile station eNB ... radio base station 11 ... control unit 12 ... transmitting unit 13 ... receiving unit

Claims (2)

A wireless base station,
A transmission unit configured to transmit a synchronization request to the mobile station when it is determined that synchronization needs to be established in the uplink with the mobile station;
The transmitter is configured to transmit the synchronization request to the mobile station in an on period of the mobile station when intermittent reception control is applied to the mobile station.
The transmission unit is configured to retransmit a predetermined number of synchronization requests when synchronization establishment in the uplink by the synchronization request is not successful.
The transmission unit is configured to retransmit a synchronization request during an ON period of the next mobile station when synchronization establishment in the uplink by the predetermined number of synchronization requests is not successful. Wireless base station.   2. The radio base station according to claim 1, wherein the number of retransmissions to be performed after retransmission in the ON period of the mobile station is configured to be different from the predetermined number of times.

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