WO2013054796A1 - Base station and communication control method - Google Patents

Base station and communication control method Download PDF

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Publication number
WO2013054796A1
WO2013054796A1 PCT/JP2012/076157 JP2012076157W WO2013054796A1 WO 2013054796 A1 WO2013054796 A1 WO 2013054796A1 JP 2012076157 W JP2012076157 W JP 2012076157W WO 2013054796 A1 WO2013054796 A1 WO 2013054796A1
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synchronization
syncrequest
uplink
base station
mobile station
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PCT/JP2012/076157
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French (fr)
Japanese (ja)
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徹 内野
アニール ウメシュ
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株式会社エヌ・ティ・ティ・ドコモ
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/0005—Synchronisation arrangements synchronizing of arrival of multiple uplinks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/001—Synchronization between nodes
    • H04W56/0015—Synchronization between nodes one node acting as a reference for the others
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/004—Synchronisation arrangements compensating for timing error of reception due to propagation delay
    • H04W56/0045—Synchronisation arrangements compensating for timing error of reception due to propagation delay compensating for timing error by altering transmission time

Definitions

  • the present invention relates to a base station and a communication control method for transmitting a SyncRequest requesting establishment of uplink synchronization to a mobile station when uplink synchronization loss is detected.
  • LTE Long Term Evolution
  • 3GPP 3rd Generation Partnership Project
  • eNB base station
  • UL uplink
  • 3GPP 3rd Generation Partnership Project
  • a SyncRequest is transmitted to a station via a downlink control physical channel (PDCCH) (see, for example, Non-Patent Document 1).
  • the mobile station that has received the SyncRequest executes a Random access (RA) procedure to reestablish uplink synchronization.
  • RA Random access
  • the conventional uplink synchronization establishment method described above has the following problems. In other words, if the mobile station fails to receive SyncRequest, the RA procedure is not executed, so uplink synchronization is not reestablished and the uplink out-of-sync state continues for a long time. .
  • uplink individual resources uplink resources for reporting feedback information such as the channel Quality Indicator (CQI) of the mobile station
  • CQI channel Quality Indicator
  • An object is to provide a station and a communication control method.
  • a first feature of the present invention is that a synchronization state detection unit (UL out-of-sync detection unit 105) that detects whether it is necessary to establish uplink synchronization with a mobile station (for example, mobile station 200A),
  • a synchronization request transmission unit (synchronization request transmission unit 107) configured to transmit a SyncRequest requesting the mobile station to establish the uplink synchronization when the synchronization state detection unit determines that the uplink synchronization establishment is necessary;
  • the synchronization request transmission unit transmits a new SyncRequest to the mobile station when the synchronization state detection unit continues to establish the uplink synchronization even after transmitting the SyncRequest.
  • the gist is that it is a base station (base station 100).
  • the second feature of the present invention is that the communication device detects whether it is necessary to establish uplink synchronization established with the mobile station, and that the communication device requires establishment of the uplink synchronization. Detecting a synchronization request for establishing uplink synchronization to the mobile station, and in the step of transmitting the SyncRequest, the synchronization establishment of the uplink is performed even after transmitting the SyncRequest. This is a communication control method for transmitting a new SyncRequest to the mobile station when the necessary state continues. *
  • FIG. 1 is an overall schematic configuration diagram of a radio communication system according to an embodiment of the present invention.
  • FIG. 2 is a functional block configuration diagram of the base station 100 according to the embodiment of the present invention.
  • FIG. 3 is a diagram showing a communication sequence between the base station 100 and the mobile station 200A from detection of uplink synchronization loss to establishment of uplink synchronization according to the embodiment of the present invention.
  • FIG. 4 is a view showing a SyncRequest transmission operation flow in the base station 100 (PF) according to the embodiment of the present invention.
  • FIG. 5 is a diagram showing a communication sequence between the base station 100 and the mobile station 200A up to establishment of uplink synchronization according to a modification of the present invention.
  • FIG. 1 is an overall schematic configuration diagram of a radio communication system according to the present embodiment.
  • the radio communication system according to the present embodiment employs a Long Term Evolution (LTE) scheme, and includes a core network 50, a base station 100 (eNB), and mobile stations 200A and 200B (UE). Including.
  • LTE Long Term Evolution
  • eNB base station 100
  • UE mobile stations 200A and 200B
  • the base station 100 is connected to the core network 50.
  • Base station 100 forms cell C1 and performs radio communication with mobile stations 200A and 200B according to the LTE scheme.
  • the base station 100 transmits a SyncRequest requesting establishment of uplink synchronization to the mobile station 200A (or mobile station 200B, hereinafter the same).
  • the mobile station 200A executes a Random access (RA) procedure to reestablish uplink synchronization.
  • RA Random access
  • FIG. 2 is a functional block configuration diagram of the base station 100.
  • the base station 100 includes a wireless communication unit 101, a data transmission / reception unit 103, a UL synchronization loss detection unit 105, and a synchronization request transmission unit 107. Note that the base station 100 realizes these functional blocks by the platform unit (PF) and the application unit (AP).
  • PF platform unit
  • AP application unit
  • the wireless communication unit 101 performs wireless communication with the mobile station 200A (200B) according to the LTE system.
  • the data transmission / reception unit 103 transmits / receives control data (C-plane data) and user data (U-Plane data) for the mobile station 200A via the wireless communication unit 101.
  • the data transmitter / receiver 103 transmits SyncRequest, which is a type of control data transmitted from the synchronization request transmitter 107, to the mobile station 200A via the downlink control physical channel (PDCCH).
  • SyncRequest which is a type of control data transmitted from the synchronization request transmitter 107, to the mobile station 200A via the downlink control physical channel (PDCCH).
  • the UL out-of-synchronization detection unit 105 detects whether it is necessary to establish uplink (UL) synchronization with the mobile station 200A. Specifically, UL out-of-synchronization detection unit 105 detects an uplink out-of-synchronization set with mobile station 200A. In the present embodiment, the UL synchronization loss detection unit 105 constitutes a synchronization state detection unit.
  • the UL out-of-synchronization detection unit 105 monitors the quality of the uplink physical channel (Sounding RS or PUCCH) transmitted from the mobile station 200A.
  • the UL out-of-synchronization detection unit 105 detects out-of-synchronization when the quality of the uplink physical channel transmitted from the mobile station 200A falls below the threshold for a predetermined time (or a predetermined number of observations).
  • the synchronization request transmission unit 107 When the UL synchronization loss detection unit 105 determines that uplink synchronization needs to be established, specifically, when synchronization loss is detected, the synchronization request transmission unit 107 establishes uplink synchronization with the mobile station 200A. Send a SyncRequest requesting. Specifically, as described above, the synchronization request transmission unit 107 transmits SyncRequest to the mobile station 200A via the PDCCH.
  • the synchronization request transmission unit 107 uses the UL out-of-sync detection unit 105 even after transmitting a SyncRequest once in association with the detection of uplink out-of-synchronization detected by the UL out-of-synchronization detection unit 105.
  • a new SyncRequest is transmitted to the mobile station 200A.
  • the synchronization request transmission unit 107 generates a new SyncRequest when the uplink synchronization loss continues by the UL synchronization loss detection unit 105 even after a predetermined time has elapsed since the transmission of the already transmitted SyncRequest. Send.
  • the synchronization request transmission unit 107 can repeatedly transmit SyncRequest up to a predetermined number of times (N syncreq ) when the uplink synchronization loss continues.
  • FIG. 3 shows a communication sequence between the base station 100 and the mobile station 200A from detection of uplink loss of synchronization to establishment of uplink synchronization.
  • the base station 100 detects uplink out-of-synchronization (S10), and notifies the base station 100 (AP) that out-of-synchronization is detected (S20).
  • the base station 100 (PF) When the base station 100 (PF) detects an uplink out of synchronization, the base station 100 (PF) continuously transmits a SyncRequest to the mobile station 200A a plurality of times (S30). When the mobile station 200A receives the SyncRequest normally, the mobile station 200A executes the RA procedure and reestablishes uplink synchronization.
  • the base station 100 when the uplink synchronization is not re-established between the subframe in which the SyncRequest is transmitted and the subframe after a predetermined time specified by Timer synqrec , Resend SyncRequest to If uplink synchronization is reestablished from the subframe in which the first SyncRequest is transmitted to the subframe after the lapse of a predetermined time specified by Timer synqrec , the uplink synchronization is not performed without resending the SyncRequest. The establishment process is terminated.
  • the base station 100 can repeatedly transmit up to a predetermined number of SyncRequests (N syncreq ) when the uplink synchronization loss continues.
  • the base station 100 (PF) from the sub-frame transmitted with N Syncreq times SyncRequest until subframe after the predetermined period of time defined by Timer Synqrec, if the synchronization of the uplink is not re-established, the SyncRequest After the transmission, the base station 100 (AP) is notified that the uplink synchronization loss continues (S40).
  • FIG. 4 shows a SyncRequest transmission operation flow in the base station 100 (PF).
  • the base station 100 (PF) detects uplink out-of-synchronization (S110), and notifies the base station 100 (AP) of mail that the out-of-synchronization is detected (S120).
  • S110 and S120 correspond to S10 and S20 shown in FIG.
  • the base station 100 (PF) determines whether uplink synchronization has been established by the transmitted SyncRequest (S150).
  • the base station 100 adds the value of the parameter k (S160), and determines whether k is lower than N syncreq (S170).
  • a new SyncRequest is transmitted if the uplink is out of synchronization even after a predetermined time (Timer synqrec ) has elapsed since the transmission of the SyncRequest.
  • SyncRequest is repeatedly transmitted up to a predetermined number of times (N syncreq ). Therefore, uplink synchronization can be re-established reliably and quickly while suppressing unnecessary transmission of SyncRequest.
  • the SyncRequest when uplink synchronization loss is detected by the UL synchronization loss detection unit 105, the SyncRequest is transmitted. However, as illustrated in FIG. 5, uplink individual resources are released. When the resumption of data transmission via the downlink in the state is detected, the synchronization request transmission unit 107 may transmit SyncRequest.
  • FIG. 5 is a diagram showing a communication sequence between the base station 100 and the mobile station 200A up to establishment of uplink synchronization according to a modification of the present invention.
  • the base station 100 does not monitor the uplink synchronization state. Since CQI is not reported from the mobile station 200A, the uplink is always out of synchronization.
  • the base station 100 and the mobile station 200A need to reconfigure uplink individual resources. Since the uplink synchronization is not established, the base station 100 first transmits a SyncRequest to cause the mobile station 200A to activate the RA procedure (S220 to S230).
  • the operation of S240 is the same as the operation of S40 described above (see FIG. 3).
  • SyncRequest when uplink synchronization loss continues, SyncRequest is repeatedly transmitted up to a predetermined number of times (N syncreq ), but uplink synchronization loss occurs after the first SyncRequest. If it continues, SyncRequest may be transmitted multiple times without sequentially confirming that uplink synchronization has been established.
  • the base station 100 executes processing related to transmission of SyncRequest.
  • all or part of such processing is performed by, for example, another communication device connected to the core network 50. (For example, MME) may be executed.
  • Core network 100 Base station 101 .
  • Wireless communication unit 103 Data transmission / reception unit 105 ... UL out-of-sync detection unit 107 ... Synchronization request transmission unit 200A, 200B ... Mobile station C1 ... Cell

Abstract

Provided are a base station and a communication control method with which it is possible to more definitively and quickly reestablish uplink synchronization when a necessity for uplink synchronization establishment is detected. A base station (100) is provided with: a UL synchronization loss detection unit (105) for detecting whether or not synchronization establishment of an uplink set to a mobile terminal (200A) is necessary or not; and a synchronization request transmission unit (107) for transmitting SyncRequest for requesting uplink synchronization establishment to the mobile terminal when the UL synchronization loss detection unit (105) determines that uplink synchronization establishment is necessary. Even after transmission of the SyncRequest, the synchronization request transmission unit (107) transmits a new SyncRequest to the mobile terminal (200A) when a state where the UL synchronization loss detection unit (105) determines that uplink synchronization establishment is necessary continues.

Description

基地局及び通信制御方法Base station and communication control method
　本発明は、上りリンクの同期外れが検出された場合、移動局に当該上りリンクの同期確立を要求するSyncRequestを送信する基地局及び通信制御方法に関する。 The present invention relates to a base station and a communication control method for transmitting a SyncRequest requesting establishment of uplink synchronization to a mobile station when uplink synchronization loss is detected.
　3rd Generation Partnership Project（3GPP）において標準化されているLong Term Evolution（LTE）では、基地局（eNB）が上りリンク（UL）の同期外れを検出すると、基地局が当該上りリンクを設定している移動局に対して、下り制御物理チャネル（PDCCH）を介してSyncRequestを送信することが規定されている（例えば、非特許文献１参照）。SyncRequestを受信した移動局は、Random access（RA）手順を実行し、上りリンクの同期を再確立する。 In Long Term Evolution (LTE), standardized in 3rd Generation Partnership Project (3GPP), when the base station (eNB) detects that the uplink (UL) is out of synchronization, the base station sets the uplink. It is defined that a SyncRequest is transmitted to a station via a downlink control physical channel (PDCCH) (see, for example, Non-Patent Document 1). The mobile station that has received the SyncRequest executes a Random access (RA) procedure to reestablish uplink synchronization.
　しかしながら、上述した従来の上りリンクの同期の確立方法には、次のような問題があった。すなわち、移動局がSyncRequestの受信に失敗すると、RA手順も実行されないため、上りリンクの同期が再確立されず、上りリンクの同期外れの状態が長時間に渡って継続してしまう問題があった。 However, the conventional uplink synchronization establishment method described above has the following problems. In other words, if the mobile station fails to receive SyncRequest, the RA procedure is not executed, so uplink synchronization is not reestablished and the uplink out-of-sync state continues for a long time. .
　また、このような状態は、上りリンクの個別リソース（当該移動局のChannel Quality Indicator（CQI）などのフィードバック情報を報告するための上りリンクのリソース）が解放された状態において、下りリンクを介したデータの送信再開を検出した場合も同様である。 In addition, such a state is established when uplink individual resources (uplink resources for reporting feedback information such as the channel Quality Indicator (CQI) of the mobile station) are released via the downlink. The same applies when the resumption of data transmission is detected.
　そこで、本発明は、このような状況に鑑みてなされたものであり、上りリンクの同期確立が必要なことが検出された場合において、より確実かつ迅速に上りリンクの同期を再確立し得る基地局及び通信制御方法の提供を目的とする。 Therefore, the present invention has been made in view of such a situation, and when it is detected that uplink synchronization needs to be established, a base that can reestablish uplink synchronization more reliably and quickly. An object is to provide a station and a communication control method.
　本発明の第１の特徴は、移動局（例えば、移動局200A）と設定される上りリンクの同期確立が必要か否かを検出する同期状態検出部（UL同期外れ検出部105）と、前記同期状態検出部によって前記上りリンクの同期確立が必要と判定された場合、前記移動局に前記上りリンクの同期確立を要求するSyncRequestを送信する同期要求送信部（同期要求送信部107）とを備え、前記同期要求送信部は、前記SyncRequestを送信した後においても、前記同期状態検出部による前記上りリンクの同期確立が必要な状態が継続している場合、前記移動局に新たなSyncRequestを送信する基地局（基地局100）であることを要旨とする。 A first feature of the present invention is that a synchronization state detection unit (UL out-of-sync detection unit 105) that detects whether it is necessary to establish uplink synchronization with a mobile station (for example, mobile station 200A), A synchronization request transmission unit (synchronization request transmission unit 107) configured to transmit a SyncRequest requesting the mobile station to establish the uplink synchronization when the synchronization state detection unit determines that the uplink synchronization establishment is necessary; The synchronization request transmission unit transmits a new SyncRequest to the mobile station when the synchronization state detection unit continues to establish the uplink synchronization even after transmitting the SyncRequest. The gist is that it is a base station (base station 100).
　本発明の第２の特徴は、通信装置が、移動局と設定される上りリンクの同期確立が必要か否かを検出するステップと、前記通信装置が、前記上りリンクの同期確立が必要なことを検出した場合、前記移動局に前記上りリンクの同期確立を要求するSyncRequestを送信するステップとを備え、前記SyncRequestを送信するステップでは、前記SyncRequestを送信した後においても、前記上りリンクの同期確立が必要な状態が継続している場合、前記移動局に新たなSyncRequestを送信する通信制御方法であることを要旨とする。　 The second feature of the present invention is that the communication device detects whether it is necessary to establish uplink synchronization established with the mobile station, and that the communication device requires establishment of the uplink synchronization. Detecting a synchronization request for establishing uplink synchronization to the mobile station, and in the step of transmitting the SyncRequest, the synchronization establishment of the uplink is performed even after transmitting the SyncRequest. This is a communication control method for transmitting a new SyncRequest to the mobile station when the necessary state continues. *
図１は、本発明の実施形態に係る無線通信システムの全体概略構成図である。FIG. 1 is an overall schematic configuration diagram of a radio communication system according to an embodiment of the present invention. 図２は、本発明の実施形態に係る基地局100の機能ブロック構成図である。FIG. 2 is a functional block configuration diagram of the base station 100 according to the embodiment of the present invention. 図３は、本発明の実施形態に係る上りリンクの同期外れ検出から上りリンクの同期確立までの基地局100と移動局200Aとによる通信シーケンスを示す図である。FIG. 3 is a diagram showing a communication sequence between the base station 100 and the mobile station 200A from detection of uplink synchronization loss to establishment of uplink synchronization according to the embodiment of the present invention. 図４は、本発明の実施形態に係る基地局100（PF）におけるSyncRequestの送信動作フローを示す図である。FIG. 4 is a view showing a SyncRequest transmission operation flow in the base station 100 (PF) according to the embodiment of the present invention. 図５は、本発明の変更例に係る上りリンクの同期確立までの基地局100と移動局200Aとによる通信シーケンスを示す図である。FIG. 5 is a diagram showing a communication sequence between the base station 100 and the mobile station 200A up to establishment of uplink synchronization according to a modification of the present invention.
　次に、本発明の実施形態について説明する。なお、以下の図面の記載において、同一または類似の部分には、同一または類似の符号を付している。ただし、図面は模式的なものであり、各寸法の比率などは現実のものとは異なることに留意すべきである。 Next, an embodiment of the present invention will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.
　したがって、具体的な寸法などは以下の説明を参酌して判断すべきものである。また、図面相互間においても互いの寸法の関係や比率が異なる部分が含まれていることは勿論である。 Therefore, specific dimensions should be determined in consideration of the following explanation. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.
　（１）無線通信システムの全体概略構成
　図１は、本実施形態に係る無線通信システムの全体概略構成図である。図１に示すように、本実施形態に係る無線通信システムは、Long Term Evolution（LTE）方式を採用しており、コアネットワーク50、基地局100（eNB）及び移動局200A, 200B（UE）を含む。 (1) Overall Schematic Configuration of Radio Communication System FIG. 1 is an overall schematic configuration diagram of a radio communication system according to the present embodiment. As shown in FIG. 1, the radio communication system according to the present embodiment employs a Long Term Evolution (LTE) scheme, and includes a core network 50, a base station 100 (eNB), and mobile stations 200A and 200B (UE). Including.
　基地局100は、コアネットワーク50に接続されている。基地局100は、セルC1を形成し、移動局200A及び200BとLTE方式に従った無線通信を実行する。特に、本実施形態では、基地局100は、上りリンクの同期外れが検出された場合、移動局200A（または移動局200B、以下同）に当該上りリンクの同期確立を要求するSyncRequestを送信する。 The base station 100 is connected to the core network 50. Base station 100 forms cell C1 and performs radio communication with mobile stations 200A and 200B according to the LTE scheme. In particular, in the present embodiment, when uplink synchronization loss is detected, the base station 100 transmits a SyncRequest requesting establishment of uplink synchronization to the mobile station 200A (or mobile station 200B, hereinafter the same).
　移動局200Aは、基地局100からSyncRequestを受信すると、Random access（RA）手順を実行し、上りリンクの同期を再確立する。 When the mobile station 200A receives the SyncRequest from the base station 100, the mobile station 200A executes a Random access (RA) procedure to reestablish uplink synchronization.
　（２）無線通信システムの機能ブロック構成
　次に、本実施形態に係る無線通信システムの機能ブロック構成について説明する。具体的には、基地局100の機能ブロック構成について説明する。図２は、基地局100の機能ブロック構成図である。 (2) Functional Block Configuration of Radio Communication System Next, a functional block configuration of the radio communication system according to the present embodiment will be described. Specifically, the functional block configuration of base station 100 will be described. FIG. 2 is a functional block configuration diagram of the base station 100.
　図２に示すように、基地局100は、無線通信部101、データ送受信部103、UL同期外れ検出部105及び同期要求送信部107を備える。なお、基地局100は、これらの機能ブロックを、プラットフォーム部（PF）及びアプリケーション部（AP）によって実現する。 As shown in FIG. 2, the base station 100 includes a wireless communication unit 101, a data transmission / reception unit 103, a UL synchronization loss detection unit 105, and a synchronization request transmission unit 107. Note that the base station 100 realizes these functional blocks by the platform unit (PF) and the application unit (AP).
　無線通信部101は、移動局200A（200B）とLTE方式に従った無線通信を実行する。 The wireless communication unit 101 performs wireless communication with the mobile station 200A (200B) according to the LTE system.
　データ送受信部103は、無線通信部101を介して移動局200A向けの制御データ（C-planeデータ）及びユーザデータ（U-Planeデータ）を送受信する。特に、本実施形態では、データ送受信部103は、同期要求送信部107から送信された制御データの一種であるSyncRequestを下り制御物理チャネル（PDCCH）を介して移動局200Aに送信する。 The data transmission / reception unit 103 transmits / receives control data (C-plane data) and user data (U-Plane data) for the mobile station 200A via the wireless communication unit 101. In particular, in this embodiment, the data transmitter / receiver 103 transmits SyncRequest, which is a type of control data transmitted from the synchronization request transmitter 107, to the mobile station 200A via the downlink control physical channel (PDCCH).
　UL同期外れ検出部105は、移動局200Aと設定される上りリンク（UL）の同期確立が必要か否かを検出する。具体的には、UL同期外れ検出部105は、移動局200Aと設定される上りリンクの同期外れを検出する。本実施形態において、UL同期外れ検出部105は、同期状態検出部を構成する。 The UL out-of-synchronization detection unit 105 detects whether it is necessary to establish uplink (UL) synchronization with the mobile station 200A. Specifically, UL out-of-synchronization detection unit 105 detects an uplink out-of-synchronization set with mobile station 200A. In the present embodiment, the UL synchronization loss detection unit 105 constitutes a synchronization state detection unit.
　UL同期外れ検出部105は、移動局200Aから送信される上り物理チャネル（Sounding RSやPUCCH）の品質を監視する。UL同期外れ検出部105は、移動局200Aから送信される上り物理チャネルの品質が所定時間（或いは、所定の観測回数）に渡って閾値を下回ると、同期外れを検出する。 The UL out-of-synchronization detection unit 105 monitors the quality of the uplink physical channel (Sounding RS or PUCCH) transmitted from the mobile station 200A. The UL out-of-synchronization detection unit 105 detects out-of-synchronization when the quality of the uplink physical channel transmitted from the mobile station 200A falls below the threshold for a predetermined time (or a predetermined number of observations).
　同期要求送信部107は、UL同期外れ検出部105によって上りリンクの同期確立が必要と判定された場合、具体的には、同期外れが検出された場合、移動局200Aに当該上りリンクの同期確立を要求するSyncRequestを送信する。具体的には、上述したように、同期要求送信部107は、PDCCHを介してSyncRequestを移動局200Aに送信する。 When the UL synchronization loss detection unit 105 determines that uplink synchronization needs to be established, specifically, when synchronization loss is detected, the synchronization request transmission unit 107 establishes uplink synchronization with the mobile station 200A. Send a SyncRequest requesting. Specifically, as described above, the synchronization request transmission unit 107 transmits SyncRequest to the mobile station 200A via the PDCCH.
　特に、本実施形態では、同期要求送信部107は、UL同期外れ検出部105によって上りリンクの同期外れが検出されたことに伴って一度SyncRequestを送信した後においても、UL同期外れ検出部105による当該上りリンクの同期外れが継続している場合、移動局200Aに新たなSyncRequestを送信する。より具体的には、同期要求送信部107は、既に送信したSyncRequestの送信から所定時間が経過してもUL同期外れ検出部105による当該上りリンクの同期外れが継続している場合、新たなSyncRequestを送信する。 In particular, in the present embodiment, the synchronization request transmission unit 107 uses the UL out-of-sync detection unit 105 even after transmitting a SyncRequest once in association with the detection of uplink out-of-synchronization detected by the UL out-of-synchronization detection unit 105. When the uplink synchronization loss continues, a new SyncRequest is transmitted to the mobile station 200A. More specifically, the synchronization request transmission unit 107 generates a new SyncRequest when the uplink synchronization loss continues by the UL synchronization loss detection unit 105 even after a predetermined time has elapsed since the transmission of the already transmitted SyncRequest. Send.
　また、同期要求送信部107は、当該上りリンクの同期外れが継続している場合、SyncRequestを所定回数（Nsyncreq）まで繰り返し送信することができる。 Also, the synchronization request transmission unit 107 can repeatedly transmit SyncRequest up to a predetermined number of times (N syncreq ) when the uplink synchronization loss continues.
　（３）無線通信システムの動作
　次に、本実施形態に係る無線通信システムの動作について説明する。具体的には、基地局100（eNB）と移動局200A（UE）とによる上りリンクの同期確立動作について説明する。 (3) Operation of Radio Communication System Next, the operation of the radio communication system according to the present embodiment will be described. Specifically, an uplink synchronization establishment operation by the base station 100 (eNB) and the mobile station 200A (UE) will be described.
　（３．１）通信シーケンス
　図３は、上りリンクの同期外れ検出から上りリンクの同期確立までの基地局100と移動局200Aとによる通信シーケンスを示す。 (3.1) Communication Sequence FIG. 3 shows a communication sequence between the base station 100 and the mobile station 200A from detection of uplink loss of synchronization to establishment of uplink synchronization.
　図３に示すように、基地局100（PF）は、上りリンクの同期外れを検出（S10）し、同期外れを検出したことを基地局100（AP）に通知する（S20）。 As shown in FIG. 3, the base station 100 (PF) detects uplink out-of-synchronization (S10), and notifies the base station 100 (AP) that out-of-synchronization is detected (S20).
　基地局100（PF）は、上りリンクの同期外れを検出すると、移動局200AにSyncRequestを複数回数に渡って連続して送信する（S30）。なお、移動局200Aは、SyncRequestを正常に受信すると、RA手順を実行し、上りリンクの同期を再確立する。 When the base station 100 (PF) detects an uplink out of synchronization, the base station 100 (PF) continuously transmits a SyncRequest to the mobile station 200A a plurality of times (S30). When the mobile station 200A receives the SyncRequest normally, the mobile station 200A executes the RA procedure and reestablishes uplink synchronization.
　具体的には、基地局100（PF）は、SyncRequestを送信したサブフレームからTimersynqrecによって規定される所定時間経過後のサブフレームまでに、当該上りリンクの同期が再確立されない場合、移動局200Aに対してSyncRequestを再送する。なお、最初のSyncRequestを送信したサブフレームからTimersynqrecによって規定される所定時間経過後のサブフレームまでに当該上りリンクの同期が再確立された場合には、SyncRequestを再送せずに上りリンクの同期確立処理を終了する。 Specifically, the base station 100 (PF), when the uplink synchronization is not re-established between the subframe in which the SyncRequest is transmitted and the subframe after a predetermined time specified by Timer synqrec , Resend SyncRequest to If uplink synchronization is reestablished from the subframe in which the first SyncRequest is transmitted to the subframe after the lapse of a predetermined time specified by Timer synqrec , the uplink synchronization is not performed without resending the SyncRequest. The establishment process is terminated.
　つまり、基地局100（PF）は、当該上りリンクの同期外れが継続している場合、SyncRequestの所定回数（Nsyncreq）まで繰り返し送信することができる。 That is, the base station 100 (PF) can repeatedly transmit up to a predetermined number of SyncRequests (N syncreq ) when the uplink synchronization loss continues.
　また、基地局100（PF）は、Nsyncreq回のSyncRequestを送信したサブフレームからTimersynqrecによって規定される所定時間経過後のサブフレームまでに、当該上りリンクの同期が再確立されない場合、SyncRequestの送信後においても当該上りリンクの同期外れが継続していることを基地局100（AP）に通知する（S40）。 Further, the base station 100 (PF) from the sub-frame transmitted with N Syncreq times SyncRequest until subframe after the predetermined period of time defined by Timer Synqrec, if the synchronization of the uplink is not re-established, the SyncRequest After the transmission, the base station 100 (AP) is notified that the uplink synchronization loss continues (S40).
　（３．２）基地局100の動作フロー
　図４は、基地局100（PF）におけるSyncRequestの送信動作フローを示す。図４に示すように、基地局100（PF）は、上りリンクの同期外れを検出（S110）し、同期外れを検出したことを基地局100（AP）にメール通知する（S120）。なお、S110及びS120は、図３に示したS10及びS20と対応する。 (3.2) Operation Flow of Base Station 100 FIG. 4 shows a SyncRequest transmission operation flow in the base station 100 (PF). As shown in FIG. 4, the base station 100 (PF) detects uplink out-of-synchronization (S110), and notifies the base station 100 (AP) of mail that the out-of-synchronization is detected (S120). S110 and S120 correspond to S10 and S20 shown in FIG.
　次いで、基地局100（PF）は、パラメータk=1に設定（S130）し、移動局200AにSyncRequestを送信する（S140）。基地局100（PF）は、送信したSyncRequestによって、上りリンクの同期が確立したか否かを判定する（S150）。 Next, the base station 100 (PF) sets the parameter k = 1 (S130) and transmits a SyncRequest to the mobile station 200A (S140). The base station 100 (PF) determines whether uplink synchronization has been established by the transmitted SyncRequest (S150).
　上りリンクの同期外れが継続している場合、基地局100（PF）は、パラメータkの値を加算（S160）し、kがNsyncreqを下回っているか否かを判定する（S170）。 When uplink synchronization loss continues, the base station 100 (PF) adds the value of the parameter k (S160), and determines whether k is lower than N syncreq (S170).
　kがNsyncreqと一致する（または上回る）場合、基地局100（PF）は、SyncRequestの送信後においても当該上りリンクの同期外れが継続していることを基地局100（AP）に通知する（S180）。なお、S180は、図３に示したS40と対応する。 When k matches (or exceeds) N syncreq , the base station 100 (PF) notifies the base station 100 (AP) that the synchronization loss of the uplink continues even after transmission of SyncRequest ( S180). Note that S180 corresponds to S40 shown in FIG.
　（４）作用・効果
　基地局100（PF）によれば、一度SyncRequestを移動局200Aに送信した後においても、当該上りリンクの同期外れが継続している場合、移動局200Aに新たなSyncRequestが送信される。このため、移動局200Aが最初のSyncRequestの受信に失敗した場合でも、上りリンクの同期が再確立されず、上りリンクの同期外れの状態が長時間に渡って継続してしまうことを防止できる。このため、基地局100（PF）によれば上りリンクの同期外れが検出された場合において、より確実かつ迅速に上りリンクの同期を再確立し得る。 (4) Operation / Effect According to the base station 100 (PF), even if the SyncRequest is once transmitted to the mobile station 200A and the uplink is out of synchronization, a new SyncRequest is sent to the mobile station 200A. Sent. For this reason, even when the mobile station 200A fails to receive the first SyncRequest, uplink synchronization is not re-established, and it is possible to prevent the uplink out-of-sync condition from continuing for a long time. For this reason, according to the base station 100 (PF), uplink synchronization can be re-established more reliably and quickly when a loss of uplink synchronization is detected.
　本実施形態では、SyncRequestの送信から所定時間（Timersynqrec）が経過しても当該上りリンクの同期外れが継続している場合、新たなSyncRequestが送信される。また、当該上りリンクの同期外れが継続している場合、SyncRequestが所定回数（Nsyncreq）まで繰り返し送信される。このため、不要なSyncRequestの送信を抑制しつつ、確実かつ迅速に上りリンクの同期を再確立し得る。 In the present embodiment, a new SyncRequest is transmitted if the uplink is out of synchronization even after a predetermined time (Timer synqrec ) has elapsed since the transmission of the SyncRequest. When the uplink synchronization loss continues, SyncRequest is repeatedly transmitted up to a predetermined number of times (N syncreq ). Therefore, uplink synchronization can be re-established reliably and quickly while suppressing unnecessary transmission of SyncRequest.
　（５）その他の実施形態
　上述したように、本発明の一実施形態を通じて本発明の内容を開示したが、この開示の一部をなす論述及び図面は、本発明を限定するものであると理解すべきではない。この開示から当業者には様々な代替実施の形態が明らかとなろう。 (5) Other Embodiments As described above, the content of the present invention has been disclosed through one embodiment of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. should not do. From this disclosure, various alternative embodiments will be apparent to those skilled in the art.
　例えば、上述した実施形態では、UL同期外れ検出部105によって上りリンクの同期外れが検出された場合、SyncRequestを送信するようにしたが、図５に示すように、上りリンクの個別リソースが解放された状態における下りリンクを介したデータの送信再開を検出した場合、同期要求送信部107がSyncRequestを送信するようにしてもよい。 For example, in the above-described embodiment, when uplink synchronization loss is detected by the UL synchronization loss detection unit 105, the SyncRequest is transmitted. However, as illustrated in FIG. 5, uplink individual resources are released. When the resumption of data transmission via the downlink in the state is detected, the synchronization request transmission unit 107 may transmit SyncRequest.
　図５は、本発明の変更例に係る上りリンクの同期確立までの基地局100と移動局200Aとによる通信シーケンスを示す図である。 FIG. 5 is a diagram showing a communication sequence between the base station 100 and the mobile station 200A up to establishment of uplink synchronization according to a modification of the present invention.
　図５に示すように、基地局100から定期的に送信されるTiming Advance（TA）を受信しない時間がTA timerによって計測される所定時間以上継続すると、上り（UL）リンクの個別リソース（移動局200AのCQIなどのフィードバック情報を報告するためのULリソース）を解放する（S210）。当該個別リソースを解放した移動局200Aに関して、基地局100は、上りリンクの同期状態を監視しない。移動局200AからCQIが報告されないため、必ず上りリンクが同期外れの状態となる。 As shown in FIG. 5, if the time during which Timing Advance (TA) periodically transmitted from the base station 100 is not received continues for a predetermined time or more measured by TA timer, an individual resource (mobile station) of the uplink (UL) link Release UL resources for reporting feedback information such as 200Q CQI (S210). Regarding the mobile station 200A that has released the dedicated resource, the base station 100 does not monitor the uplink synchronization state. Since CQI is not reported from the mobile station 200A, the uplink is always out of synchronization.
　このような状態において、下りリンクを介したデータの送信を再開する場合、基地局100及び移動局200Aは、上りリンクの個別リソースを再設定する必要がある。基地局100は、上りリンクの同期が確立されていないため、まずSyncRequestを送信して移動局200AにRA手順を起動させる（S220～S230）。なお、S240の動作は、上述したS40の動作（図３参照）と同様である。 In such a state, when data transmission via the downlink is resumed, the base station 100 and the mobile station 200A need to reconfigure uplink individual resources. Since the uplink synchronization is not established, the base station 100 first transmits a SyncRequest to cause the mobile station 200A to activate the RA procedure (S220 to S230). The operation of S240 is the same as the operation of S40 described above (see FIG. 3).
　また、上述した本発明の実施形態では、上りリンクの同期外れが継続している場合、SyncRequestが所定回数（Nsyncreq）まで繰り返し送信していたが、最初のSyncRequest後において上りリンクの同期外れが継続している場合、上りリンクの同期が確立したことを逐次確認することなく、複数回に渡ってSyncRequestを送信するようにしてもよい。 Further, in the above-described embodiment of the present invention, when uplink synchronization loss continues, SyncRequest is repeatedly transmitted up to a predetermined number of times (N syncreq ), but uplink synchronization loss occurs after the first SyncRequest. If it continues, SyncRequest may be transmitted multiple times without sequentially confirming that uplink synchronization has been established.
　上述した実施形態では、基地局100（PF）がSyncRequestの送信に関する処理を実行していたが、このような処理の全部または一部は、例えば、コアネットワーク50に接続されている他の通信装置（例えば、MME）において実行するようにしてもよい。 In the above-described embodiment, the base station 100 (PF) executes processing related to transmission of SyncRequest. However, all or part of such processing is performed by, for example, another communication device connected to the core network 50. (For example, MME) may be executed.
　このように、本発明は、ここでは記載していない様々な実施の形態などを含むことは勿論である。したがって、本発明の技術的範囲は、上述の説明から妥当な請求の範囲に係る発明特定事項によってのみ定められるものである。 Thus, it goes without saying that the present invention includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the appropriate claims from the above description.
　なお、日本国特許出願第２０１１－２２４５８１号（２０１１年１０月１２日出願）の全内容が、参照により、本願明細書に組み込まれている。 Note that the entire content of Japanese Patent Application No. 2011-224581 (filed on October 12, 2011) is incorporated herein by reference.
　本発明の特徴によれば、上りリンクの同期確立が必要なことが検出された場合において、より確実かつ迅速に上りリンクの同期を再確立し得る基地局及び通信制御方法を提供することができる。 According to the features of the present invention, it is possible to provide a base station and a communication control method that can re-establish uplink synchronization more reliably and quickly when it is detected that uplink synchronization establishment is necessary. .
　50…コアネットワーク
　100…基地局
　101…無線通信部
　103…データ送受信部
　105…UL同期外れ検出部
　107…同期要求送信部
　200A, 200B…移動局
　C1…セル 50 ... Core network 100 ... Base station 101 ... Wireless communication unit 103 ... Data transmission / reception unit 105 ... UL out-of-sync detection unit 107 ... Synchronization request transmission unit 200A, 200B ... Mobile station C1 ... Cell

Claims (6)

  1. 　移動局と設定される上りリンクの同期確立が必要か否かを検出する同期状態検出部と、
    　前記同期状態検出部によって前記上りリンクの同期確立が必要と判定された場合、前記移動局に前記上りリンクの同期確立を要求するSyncRequestを送信する同期要求送信部と
    を備え、
    　前記同期要求送信部は、前記SyncRequestを送信した後においても、前記同期状態検出部による前記上りリンクの同期確立が必要な状態が継続している場合、前記移動局に新たなSyncRequestを送信する基地局。     A synchronization state detection unit that detects whether or not uplink synchronization established with the mobile station is required;
    A synchronization request transmission unit that transmits a SyncRequest requesting the mobile station to establish the uplink synchronization when the synchronization state detection unit determines that the uplink synchronization establishment is necessary;
    The synchronization request transmission unit transmits a new SyncRequest to the mobile station if the state in which the synchronization state detection needs to be established by the synchronization state detection unit continues even after transmitting the SyncRequest. Bureau.
  2. 　前記同期要求送信部は、前記SyncRequestの送信から所定時間が経過しても前記同期状態検出部による前記上りリンクの同期確立が必要な状態が継続している場合、前記新たなSyncRequestを送信する請求項１に記載の基地局。 The synchronization request transmission unit transmits the new SyncRequest when a state requiring establishment of uplink synchronization by the synchronization state detection unit continues even after a predetermined time has elapsed since the transmission of the SyncRequest. Item 4. The base station according to Item 1.
  3. 　前記同期要求送信部は、前記上りリンクの同期確立が必要な状態が継続している場合、前記SyncRequestを所定回数まで繰り返し送信する請求項１に記載の基地局。 The base station according to claim 1, wherein the synchronization request transmission unit repeatedly transmits the SyncRequest up to a predetermined number of times when the state where the uplink synchronization needs to be established continues.
  4. 　前記同期状態検出部は、前記上りリンクの同期外れを検出し、
    　前記同期要求送信部は、前記同期状態検出部によって前記上りリンクの同期外れが検出された場合、前記SyncRequestを送信する請求項１に記載の基地局。     The synchronization state detection unit detects loss of synchronization of the uplink,
    The base station according to claim 1, wherein the synchronization request transmission unit transmits the SyncRequest when the synchronization state detection unit detects that the uplink is out of synchronization.
  5. 　前記同期状態検出部は、前記上りリンクの個別リソースが解放された状態における下りリンクを介したデータの送信再開を検出し、
    　前記同期要求送信部は、前記同期状態検出部によって前記下りリンクを介したデータの送信再開が検出された場合、前記SyncRequestを送信する請求項１に記載の基地局。     The synchronization state detection unit detects resumption of data transmission via the downlink in a state where the uplink dedicated resource is released;
    The base station according to claim 1, wherein the synchronization request transmission unit transmits the SyncRequest when the synchronization state detection unit detects resumption of data transmission via the downlink.
  6. 　通信装置が、移動局と設定される上りリンクの同期確立が必要か否かを検出するステップと、
    　前記通信装置が、前記上りリンクの同期確立が必要なことを検出した場合、前記移動局に前記上りリンクの同期確立を要求するSyncRequestを送信するステップと
    を備え、
    　前記SyncRequestを送信するステップでは、前記SyncRequestを送信した後においても、前記上りリンクの同期確立が必要な状態が継続している場合、前記移動局に新たなSyncRequestを送信する通信制御方法。     A step of detecting whether or not the communication device needs to establish uplink synchronization established with the mobile station;
    When the communication device detects that the uplink synchronization needs to be established, the communication device comprises a step of transmitting a SyncRequest requesting the uplink synchronization establishment to the mobile station,
    In the step of transmitting the SyncRequest, a communication control method of transmitting a new SyncRequest to the mobile station if the state where the uplink synchronization needs to be established continues even after transmitting the SyncRequest.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008153078A1 (en) * 2007-06-12 2008-12-18 Sharp Kabushiki Kaisha Base station device, mobile station device, program, uplink synchronization request method, and synchronization shift measurement signal transmission method

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