JP2009260566A

JP2009260566A - Communication control method

Info

Publication number: JP2009260566A
Application number: JP2008106084A
Authority: JP
Inventors: Tetsuji Iwayama; 哲治岩山
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2008-04-15
Filing date: 2008-04-15
Publication date: 2009-11-05
Anticipated expiration: 2028-04-15
Also published as: JP5153428B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication control method surely avoiding interference, relating to an UPLINK direction of a TDMA system in overreach interference from a mobile station. <P>SOLUTION: A base station 12 detects the occurrence of interference, and transmits an interference detection notice to a base station 11, and the base station 11 which receives the notice transmits interference occurrence information 41 including an identifier of the station to a subordinate mobile station. The mobile station 1 which receives the interference occurrence information 41 transmits an interference occurrence notice 42 including the identifier of the station and the identifier of the base station 11 included in the interference generation information to the base station 11 as a response. The base station 11 which receives the interference occurrence notice 42 and the base station 12 which receives the interference occurrence notice 42a by overreach, execute slot allocation to the subordinate mobile station so that a slot to be used does not overlap between the base stations on the basis of the timing of receiving the notice. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、無線通信システムにおいてオーバーリーチ干渉が発生した場合の通信制御方法に関するものである。 The present invention relates to a communication control method when overreach interference occurs in a wireless communication system.

従来から、無線通信システムにおいてオーバーリーチ干渉が発生した場合の対策が提案されている。たとえば、下記特許文献１においては、自ゾーンと同一周波数を使用する他ゾーンとの間のオーバーリーチ干渉を検出した場合に、無線フレームの開始位置をランダムに遅延させる方法が記載されている。これにより、次の無線フレーム以降では、同一周波数を使うゾーン間での無線フレームのＤＯＷＮＬＩＮＫ／ＵＰＬＩＮＫの重なり方が変わり、干渉が軽減する可能性がある。また、干渉が軽減されずに増加した場合であっても、次無線フレームで再びオーバーリーチ干渉が検出され同様の制御が行われるため、複数無線フレームにわたって見ると、いずれは干渉が軽減する方向に動作する。この方法は、干渉相手とのフレーム同期を考慮しないので、複雑な制御が不要である。 Conventionally, measures against overreach interference in a wireless communication system have been proposed. For example, Patent Document 1 below describes a method of randomly delaying the start position of a radio frame when overreach interference between the own zone and another zone using the same frequency is detected. Thereby, after the next radio frame, the overlapping manner of DOWNLINK / UPLINK of radio frames between zones using the same frequency changes, and interference may be reduced. Even if the interference increases without being reduced, overreach interference is detected again in the next radio frame and the same control is performed. Operate. Since this method does not consider frame synchronization with the interference partner, complicated control is unnecessary.

特開２００４−２６０３３５号公報JP 2004-260335 A

しかしながら、上記特許文献１の方式は、移動局からのオーバーリーチ干渉時に、基地局が無線フレームの開始位置をランダムに遅延させるため、再び干渉が発生する可能性があった。すなわち、干渉を回避できるか否かは確率でしかない、という問題があった。 However, the method of Patent Document 1 described above may cause interference again because the base station randomly delays the start position of the radio frame at the time of overreach interference from the mobile station. That is, there is a problem that whether or not interference can be avoided is only a probability.

本発明は、上記に鑑みてなされたものであって、移動局からのオーバーリーチ干渉時、ＴＤＭＡ方式のＵＰＬＩＮＫ方向に関して、確実に干渉を回避可能な通信制御方法を得ることを目的とする。 The present invention has been made in view of the above, and an object of the present invention is to obtain a communication control method that can reliably avoid interference in the UPLIN direction of the TDMA system at the time of overreach interference from a mobile station.

上述した課題を解決し、目的を達成するために、本発明は、ＴＤＭＡ方式を採用する無線通信システムにおいて、第１の基地局と通信中の特定の移動局が送信するアップリンクデータがオーバーリーチ干渉となり、第２の基地局がアップリンクデータを正常に受信することができない場合の通信制御方法であって、前記第２の基地局が、前記干渉の発生を検出する干渉検出ステップと、前記第２の基地局が、オーバーリーチ干渉の検出を通知するための干渉検出通知を、前記第１の基地局に向けて送信する干渉検出通知ステップと、前記干渉検出通知を受信した前記第１の基地局が、自局の識別子を含ませた干渉発生情報を、自局配下の移動局に対して送信する干渉発生情報送信ステップと、前記干渉発生情報を受信した前記特定の移動局が、その応答として、自局の識別子および前記干渉発生情報に含まれた第１の基地局の識別子を含ませた干渉発生通知を前記第１の基地局に送信する干渉発生通知送信ステップと、前記干渉発生通知を受信した第１の基地局、およびオーバーリーチにより前記干渉発生通知を受信した第２の基地局が、当該通知を受信したタイミングに基づき、使用するスロットが基地局間で重ならないように配下の移動局に対するスロット割当てを実行するスロット割当てステップと、を含むことを特徴とする。 In order to solve the above-described problems and achieve the object, the present invention provides a wireless communication system employing a TDMA scheme in which uplink data transmitted from a specific mobile station in communication with the first base station is overreached. A communication control method when interference occurs and the second base station cannot normally receive uplink data, wherein the second base station detects the occurrence of the interference, and The second base station transmits an interference detection notification for notifying the detection of overreach interference to the first base station, and the first base station that has received the interference detection notification. An interference occurrence information transmission step in which the base station transmits interference occurrence information including the identifier of the own station to a mobile station under its own station, and the specific mobile station that has received the interference occurrence information In response, an interference occurrence notification transmission step of transmitting an interference occurrence notification including the identifier of the local station and the identifier of the first base station included in the interference occurrence information to the first base station, and the interference Based on the timing at which the first base station that has received the notification of occurrence and the second base station that has received the notification of occurrence of interference due to overreach receive the notification, the slots to be used do not overlap between the base stations. Slot assignment step for executing slot assignment for subordinate mobile stations.

この発明によれば、確実に干渉を回避することが可能なスロット割当てが可能となる、という効果を奏する。 According to the present invention, there is an effect that slot allocation capable of reliably avoiding interference becomes possible.

以下に、本発明にかかる通信制御方法の実施の形態を図面に基づいて詳細に説明する。なお、この実施の形態によりこの発明が限定されるものではない。 Embodiments of a communication control method according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

実施の形態１．
図１は、本発明にかかる通信制御方法を実現可能な無線通信システムの実施の形態１の構成例を示す図である。図１の無線通信システムは、ＴＤＭＡ方式を採用しており、移動局１および２と、制御装置１０と、基地局１１および１２とを備える。図１に示すように、基地局１１は移動局１と通信し、基地局１２は移動局２と通信している。また、基地局１１，基地局１２は、それぞれ制御装置１０と接続されている。なお、基地局１１と基地局１２を、制御装置１０を介さず直接接続する構成としてもよい。 Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration example of a first embodiment of a wireless communication system capable of realizing the communication control method according to the present invention. The radio communication system of FIG. 1 employs the TDMA system, and includes mobile stations 1 and 2, a control device 10, and base stations 11 and 12. As shown in FIG. 1, the base station 11 communicates with the mobile station 1, and the base station 12 communicates with the mobile station 2. Further, the base station 11 and the base station 12 are each connected to the control device 10. The base station 11 and the base station 12 may be directly connected without using the control device 10.

つづいて、以上のように構成された無線通信システムにおける干渉発生時の動作を説明する。ここでは、基地局１１と移動局１が通信を行い、基地局１１が移動局１からのＵＰＬＩＮＫデータ２１を受信し、同様に、基地局１２と移動局２が通信を行い、基地局１２が移動局２からのＵＰＬＩＮＫデータ２２を受信している状態を想定する。 Next, an operation when interference occurs in the wireless communication system configured as described above will be described. Here, base station 11 and mobile station 1 communicate, base station 11 receives UPLINK data 21 from mobile station 1, and similarly, base station 12 and mobile station 2 communicate, and base station 12 Assume that the UPLINK data 22 from the mobile station 2 is received.

この状態で、移動局１からのＵＰＬＩＮＫデータ２１が、オーバーリーチにより、基地局１２にて受信可能な範囲、すなわち干渉区域に進入した場合、基地局１２は、ＵＰＬＩＮＫデータ２１を、基地局１１と同じタイミングで、同じ内容を持つＵＰＬＩＮＫデータ２１ａとして受信する。ここでの「同じタイミング」とは、無線通信レベルではなく、無線フレームを構築し伝送制御を行うアプリケーションレベルでの概念である。無線が空間中を伝搬したことによる遅延は、アプリケーションレベルではほぼ無視できるため考慮しない。 In this state, if the UPLINK data 21 from the mobile station 1 enters a range that can be received by the base station 12 due to overreach, that is, an interference area, the base station 12 transmits the UPLINK data 21 to the base station 11. Received as UPLINK data 21a having the same contents at the same timing. Here, “same timing” is not a radio communication level but a concept at an application level for constructing a radio frame and performing transmission control. Delays due to radio propagation in space are not considered because they are almost negligible at the application level.

図２は、基地局１１および基地局２１における移動局に対するスロット割当て例を示す図である。一般に、無線レベルでの同期タイミングである無線フレームには、用途別の情報がセットされている。たとえば、後述するポーリング要求、ＵＰＬＩＮＫデータ、スロット割当てを行うための制御情報等である。ここで、当該用途別の情報を“チャネル”と呼ぶ。ただし、スロット割当ての説明で用いる“スロット”は、特に明示しない限り、無線フレーム及びチャネルどちらに対しても適用できる用語とする。 FIG. 2 is a diagram showing an example of slot allocation for mobile stations in the base station 11 and the base station 21. As shown in FIG. In general, information for each use is set in a radio frame which is a synchronization timing at a radio level. For example, there are a polling request, UPLINK data, and control information for performing slot allocation, which will be described later. Here, the application-specific information is referred to as “channel”. However, “slot” used in the description of slot assignment is a term applicable to both radio frames and channels unless otherwise specified.

ＤＯＷＮＬＩＮＫ方向については、基地局が移動局を特定できる情報を付与してデータを送信する。ＴＤＭＡ方式のＵＰＬＩＮＫ方向については、複数の移動局が一つの基地局配下に存在することを考慮して、基地局が、各移動局がＵＰＬＩＮＫデータを送信するタイミングを制御する必要がある。この制御情報を「スロット割当て」と呼ぶ。 For the DOWNLINK direction, the base station transmits data with information that can identify the mobile station. For the TDMA UPLINK direction, it is necessary for the base station to control the timing at which each mobile station transmits UPLINK data in consideration of the presence of a plurality of mobile stations under one base station. This control information is called “slot allocation”.

図１において、基地局１１は、配下に移動局１のみが在圏しているので、図２に示すとおり移動局１に全スロットを割当てることができる。各スロット内の数字は移動局１の符号を示す。同様に、基地局１２は、図２に示すとおり全スロットを移動局２に割当てることができる。なお、無線の帯域が大きい場合は、全てのスロットを割当てる必要はないが、無線の帯域が小さい場合は、効率的に無線リソースを使用するために、スロットに空きがないように割当てる。 In FIG. 1, since only the mobile station 1 is in the base station 11, the base station 11 can allocate all slots to the mobile station 1 as shown in FIG. The number in each slot indicates the code of the mobile station 1. Similarly, the base station 12 can allocate all slots to the mobile station 2 as shown in FIG. When the radio band is large, it is not necessary to allocate all the slots. However, when the radio band is small, the slot is allocated so that there is no empty space in order to use radio resources efficiently.

その後、移動局１および移動局２は、それぞれのＵＰＬＩＮＫデータを、図２に示すスロット割当て結果に基づき、無線フレーム周期中の全スロットを用いて送信する。このとき、ＵＰＬＩＮＫデータ２１ａとＵＰＬＩＮＫデータ２１は同じタイミングで送信されることとなり、ＵＰＬＩＮＫデータ２１ａとＵＰＬＩＮＫデータ２２との間で干渉が発生する。 Thereafter, the mobile station 1 and the mobile station 2 transmit the respective UPLINK data using all slots in the radio frame period based on the slot assignment result shown in FIG. At this time, the UPLINK data 21 a and the UPLINK data 21 are transmitted at the same timing, and interference occurs between the UPLINK data 21 a and the UPLINK data 22.

ここで、基地局での干渉検出方法について具体的に説明する。基地局は、移動局からのＵＰＬＩＮＫデータの他に、移動局の存在確認のためのスロット割当て（「ポーリング割当て」ともいう）も行う。基地局では、ポーリング方式において、移動局からのポーリング応答が受信できた場合に、その移動局の存在を確認することができる。一方、無線品質や基地局間移動時のロスを考慮して得られる一定時間が経過してもポーリング応答が受信できなかった場合には、干渉が発生していると判断する。また、ポーリング応答が未受信で、かつ受信レベル（ＲＳＳＩ（Received Signal Strength Indication）等）が本来データを受信できる正常値に近い場合、何らかのデータを受信していると想定されるため、この場合も干渉が発生していると判断する。 Here, the interference detection method in a base station is demonstrated concretely. In addition to the UPLINK data from the mobile station, the base station also performs slot assignment (also referred to as “polling assignment”) for confirming the existence of the mobile station. In the base station, when a polling response from a mobile station can be received in the polling method, the presence of the mobile station can be confirmed. On the other hand, if the polling response is not received even after a predetermined time has been obtained in consideration of the radio quality and loss during movement between base stations, it is determined that interference has occurred. Also, if no polling response has been received and the reception level (RSSI (Received Signal Strength Indication) etc.) is close to the normal value at which data can be received, it is assumed that some data has been received. Judge that interference is occurring.

基地局１２は、たとえば、上記のように干渉を検出すると、制御装置１０に干渉検出通知３１を送信する。干渉検出通知３１を受信した制御装置１０は、基地局１１に干渉検出通知３２を送信する。干渉検出通知３１と３２は同一信号である。なお、干渉検出通知の送信については、上記処理に限らず、基地局１２が干渉検出通知を直接基地局１１に送信することとしてもよい。また、図２に示すように、基地局１１に収容されている移動局が移動局１のみの場合、基地局１１は、この時点で、基地局１２へのオーバーリーチ干渉の発生元が移動局１であることを認識する。 For example, when detecting interference as described above, the base station 12 transmits an interference detection notification 31 to the control device 10. The control device 10 that has received the interference detection notification 31 transmits an interference detection notification 32 to the base station 11. The interference detection notifications 31 and 32 are the same signal. The transmission of the interference detection notification is not limited to the above processing, and the base station 12 may directly transmit the interference detection notification to the base station 11. In addition, as shown in FIG. 2, when the mobile station accommodated in the base station 11 is only the mobile station 1, the base station 11 is the source of the overreach interference to the base station 12 at this time. Recognize that it is 1.

つづいて、基地局１１が干渉検出通知を受信した後の動作を、図面を用いて説明する。図３は、基地局１１が干渉検出通知を受信した後の動作を示す図である。基地局１１は、干渉検出通知３２を受信すると、基地局１２で干渉が発生した旨を通知する干渉発生情報４１を、自身の配下の全移動局（ここでは移動局１）に送信する（ブロードキャストする）。干渉発生情報４１は、特別にデータを定義しなくてもよく、たとえば、ＤＯＷＮＬＩＮＫデータやポーリング要求に相乗りさせる（たとえば、特定のビットにフラグを立てる等）ことが可能である。 Subsequently, an operation after the base station 11 receives the interference detection notification will be described with reference to the drawings. FIG. 3 is a diagram illustrating an operation after the base station 11 receives the interference detection notification. When the base station 11 receives the interference detection notification 32, the base station 11 transmits the interference occurrence information 41 for notifying that the interference has occurred in the base station 12 to all the mobile stations (in this case, the mobile station 1) under its control (broadcast). To do). The interference occurrence information 41 does not need to define data specially. For example, the interference occurrence information 41 can be combined with DOWNLINK data or a polling request (for example, flag a specific bit).

移動局１は、干渉発生情報４１を受信すると、干渉発生通知４２を基地局１１に送信する。一方で、移動局１は基地局１２にオーバーリーチ干渉を起こしているため、基地局１１に送信した干渉発生通知４２は、干渉発生通知４２ａとして基地局１２でも受信されることになる。移動局からのＵＰＬＩＮＫデータには移動局を特定するための移動局識別子が付与されていることが一般的であるため、基地局１２は、ＵＰＬＩＮＫデータから、干渉発生通知４２ａを送信した移動局が移動局１であることを特定することができる。すなわち、この時点で、移動局１がオーバーリーチ干渉を発生させていることを認識する。なお、移動局は、異なる基地局のエリアへ進入した場合、コンテンションのような特殊なイベントで通知することが一般的であるため、干渉発生通知４２を、コンテンションに相乗りさせる（たとえば、特定のビットにフラグを立てる等）ことにより送信可能である。 When the mobile station 1 receives the interference occurrence information 41, the mobile station 1 transmits an interference occurrence notification 42 to the base station 11. On the other hand, since the mobile station 1 causes overreach interference to the base station 12, the interference occurrence notification 42 transmitted to the base station 11 is also received by the base station 12 as the interference occurrence notification 42a. Since the mobile station identifier for identifying the mobile station is generally assigned to the UPLINK data from the mobile station, the base station 12 determines that the mobile station that has transmitted the interference occurrence notification 42a from the UPLINK data. The mobile station 1 can be identified. That is, at this point, it is recognized that the mobile station 1 is generating overreach interference. When a mobile station enters an area of a different base station, it is common to notify it by a special event such as contention. It is possible to transmit by setting a flag to the bit of

また、基地局が送信するＤＯＷＮＬＩＮＫデータには、基地局を特定する基地局識別子が付与されることが一般的である。また、移動局が受信信号に含まれている基地局識別子をＵＰＬＩＮＫデータにそのまま含めて返信することにより、基地局がその移動局と通信状態にあることを認識することも一般的である。すなわち、移動局１が干渉発生通知４２に、干渉発生情報４１に含まれた基地局１１の基地局識別子をそのまま含めて送信することにより、基地局１１は、自基地局配下の移動局からの干渉発生通知であることを認識することができる。一方で、基地局１２が受信した干渉発生通知４２ａには、基地局１１の基地局識別子が付与されているため、基地局１２は、基地局１１配下の移動局からの干渉発生通知であることを認識することができる。 Also, the DOWNLINK data transmitted by the base station is generally given a base station identifier that identifies the base station. It is also common for the mobile station to recognize that the base station is in communication with the mobile station by returning the base station identifier included in the received signal as it is in the UPLINK data. That is, when the mobile station 1 transmits the interference occurrence notification 42 by including the base station identifier of the base station 11 included in the interference occurrence information 41 as it is, the base station 11 receives information from the mobile stations under its own base station. It can be recognized that the notification is interference occurrence. On the other hand, since the base station identifier of the base station 11 is given to the interference occurrence notification 42a received by the base station 12, the base station 12 is an interference occurrence notification from a mobile station under the base station 11. Can be recognized.

つづいて、以上のようにして干渉発生が検出された場合に行われる、干渉を回避するためのスロット割当てについて説明する。図４は、基地局１１および基地局１２による、干渉発生後の移動局に対するスロット割当ての一例を示す図である。ここでは、基地局１１および基地局１２は、新たなスロット割当てを行う。 Next, slot assignment for avoiding interference performed when occurrence of interference is detected as described above will be described. FIG. 4 is a diagram illustrating an example of slot allocation to the mobile station after the occurrence of interference by the base station 11 and the base station 12. Here, the base station 11 and the base station 12 perform new slot allocation.

たとえば、干渉を発生させた移動局１を収容する基地局１１（妨害基地局とする）は、干渉発生通知４２を受信したタイミングで移動局１へのスロット割当てを行う。干渉を受けた基地局１２（被干渉基地局とする）は、干渉発生通知４２ａを受信した次のタイミングで移動局２へのスロット割当てを行う。どのタイミングでスロット割当てを行うかは、被干渉基地局と妨害基地局の間で互いに異なるように規定しておく（上記と逆のタイミングでもよい）。 For example, the base station 11 (referred to as an interfering base station) that accommodates the mobile station 1 that has caused interference assigns a slot to the mobile station 1 at the timing when the interference occurrence notification 42 is received. The base station 12 that has received the interference (assumed to be an interfered base station) assigns a slot to the mobile station 2 at the next timing after receiving the interference occurrence notification 42a. The timing at which slots are allocated is defined differently between the interfered base station and the interfering base station (the timing may be opposite to the above).

ただし、最初のスロット割当てタイミングから一定間隔後に次のスロット割当てを行わなければ再度干渉が発生してしまうため、その間隔は、全基地局で一定の時定数とする。たとえば、基地局が２つである場合は、時定数は少なくとも「１」となる。これにより、妨害基地局と被干渉基地局でスロット割当てが完全に排他的になり、干渉を回避できる。 However, if the next slot allocation is not performed after a certain interval from the first slot allocation timing, interference will occur again. Therefore, the interval is set to a constant time constant for all base stations. For example, when there are two base stations, the time constant is at least “1”. Thereby, slot allocation becomes completely exclusive between the disturbing base station and the interfered base station, and interference can be avoided.

また、図１では移動局１のみがオーバーリーチ干渉を発生させているため、一般的に考えれば、移動局１が送信タイミングをずらせばよい。しかしながら、基地局１１に移動局１以外にも移動局が収容され、複数の移動局が基地局１２にオーバーリーチ干渉を発生させた場合、移動局ごとにスロット割当てアルゴリズムを動作させることは、処理が複雑になるとともに効率的ではない。したがって、スロット割当ては、移動局単位でなく基地局単位で行うことが望ましい。すなわち、スロット割当てを行わない無線フレームまたはチャネルについては、基地局単位の制御で、全ての移動局が使用しないようにする。これにより、干渉区域に新たな移動局が進入してきた場合であっても、干渉発生後のスロット割当てが完了し、基地局間で使用するスロットの調整ができているので、さらなるオーバーリーチ干渉が発生することはない。 Further, in FIG. 1, only the mobile station 1 generates the overreach interference. Therefore, generally speaking, the mobile station 1 may shift the transmission timing. However, when a mobile station other than the mobile station 1 is accommodated in the base station 11 and a plurality of mobile stations generate overreach interference in the base station 12, operating the slot allocation algorithm for each mobile station is a processing Is complicated and inefficient. Therefore, it is desirable to perform slot allocation not in units of mobile stations but in units of base stations. That is, with respect to a radio frame or channel for which slot allocation is not performed, all mobile stations are prevented from using the base station unit control. As a result, even when a new mobile station enters the interference area, slot assignment after the occurrence of interference is completed, and adjustment of slots to be used between base stations can be performed. It does not occur.

また、スロット割当てを無線フレーム単位またはチャネル単位のいずれで行うかについては、チャネル構成に依存する点が多い。たとえば、用途別の特定情報が無線フレーム内に一つしかないような場合には、割当ては必然的に無線フレーム単位になるため、効率的に処理を行うためには無線フレーム単位の割当てが望ましい。 In addition, whether slot allocation is performed in units of radio frames or channels often depends on the channel configuration. For example, when there is only one piece of specific information for each use in a radio frame, the allocation is inevitably in units of radio frames. Therefore, in order to perform processing efficiently, allocation in units of radio frames is desirable. .

ここで、上述した時定数の最適な値についてさらに検討する。たとえば、時定数が小さい場合は、干渉が発生しているスロットを除く未使用のスロットが少なくなるため、無線リソースを有効利用することが可能となる。しかしながら、隣接する基地局が連続的に干渉発生状態になると、スロット割当ての再実行により、すでに干渉を回避した基地局で再び干渉が発生するような割当てになる可能性がある。逆に、時定数が大きい場合は、干渉が発生しているスロットを除く未使用のスロットが多くなるため、無線リソースの利用効率は悪くなる。しかしながら、隣接する基地局が連続的に干渉発生状態になった場合には、時定数が大きいので、スロット割当ての再実行により、すでに干渉を回避した基地局で再び干渉が発生するような割当てになる可能性は低い。 Here, the optimum value of the time constant described above will be further examined. For example, when the time constant is small, the number of unused slots excluding the slot where interference occurs is reduced, so that radio resources can be used effectively. However, when adjacent base stations are continuously in a state where interference occurs, there is a possibility that the re-execution of the slot allocation may result in an allocation that causes interference again in the base station that has already avoided the interference. On the other hand, when the time constant is large, the number of unused slots excluding the slot where interference occurs increases, and the utilization efficiency of radio resources deteriorates. However, when adjacent base stations are continuously in a state where interference occurs, the time constant is large. Is unlikely.

特に、列車無線通信システムの場合には、基地局の配置が面的ではなく線的になるため、各基地局は、隣接する基地局が最大でも２つしか存在しないこととなる。したがって、時定数は、少なくとも「１」であればタイミングをずらすことが可能であるが、１／２の確率で再スロット割当てが発生するため、「２」〜「４」程度が望ましい。図４には、時定数が「２」の場合の例が示されている。 In particular, in the case of a train radio communication system, since the arrangement of base stations is not planar but linear, each base station has at most two adjacent base stations. Therefore, if the time constant is at least “1”, the timing can be shifted. However, since re-slot allocation occurs with a probability of ½, “2” to “4” is desirable. FIG. 4 shows an example in which the time constant is “2”.

なお、前述した干渉区域への進入は、異なる基地局が提供するエリアへの移動の過渡状態とみなすことができる。この状態において、通信中の基地局と移動局との間では、干渉による通信断に加え、新しい基地局との位置登録による通信断が発生する。特に、列車無線通信システムにおいては、移動局（列車）は、通常、高速移動しているため、干渉発生は継続的な状態ではなく過渡的な状態であることも多い。したがって、このようなシステムでは、基地局１２は、干渉を一定回数検出した段階で干渉検出通知３１を送信するとしてもよい。 The approach to the interference area described above can be regarded as a transient state of movement to an area provided by a different base station. In this state, in addition to communication interruption due to interference, communication interruption due to location registration with a new base station occurs between the base station and the mobile station in communication. In particular, in a train radio communication system, since a mobile station (train) is usually moving at a high speed, interference often occurs in a transitional state rather than a continuous state. Therefore, in such a system, the base station 12 may transmit the interference detection notification 31 when the interference is detected a certain number of times.

以上説明したように、本実施の形態では、オーバーリーチ干渉が発生した場合に、妨害基地局と被干渉基地局との間で、干渉を発生させた移動局およびその移動局が送信する干渉発生通知のタイミング（スロット割当てのタイミング）を共有可能な構成とした。これにより、確実に干渉を回避することが可能なスロット割当てが可能となる。また、基地局間でアプリケーションレベルの同期をとる場合は、同期タイミング制御に高い精度が求められるが、本実施の形態では、簡潔な仕組みで確実性の高い同期タイミングを確立することができる。 As described above, in this embodiment, when overreach interference occurs, a mobile station that has caused interference between the disturbing base station and the interfered base station and interference generated by the mobile station are generated. The notification timing (slot allocation timing) can be shared. This makes it possible to assign a slot that can reliably avoid interference. In addition, when application-level synchronization is performed between base stations, high accuracy is required for synchronization timing control. In this embodiment, a highly reliable synchronization timing can be established with a simple mechanism.

また、本実施の形態では、特に狭帯域なシステムにおいて、一度の干渉検出でスロット割当てを行わない構成としたので、干渉を回避しつつ無線リソースを有効に利用したスロット割当てが可能となる。 Further, in this embodiment, since the slot allocation is not performed by detecting interference once in a particularly narrow band system, it is possible to perform slot allocation that effectively uses radio resources while avoiding interference.

実施の形態２．
実施の形態１では、基地局１１配下の移動局が移動局１のみの場合について説明した。本実施の形態では、基地局１１配下の移動局が複数存在する場合の干渉回避処理について説明する。 Embodiment 2. FIG.
In the first embodiment, the case where the mobile station under the base station 11 is only the mobile station 1 has been described. In this embodiment, an interference avoidance process when there are a plurality of mobile stations under the base station 11 will be described.

図５は、本発明にかかる通信制御方法を実現可能な無線通信システムの実施の形態２の構成例を示す図である。図５の無線通信システムは、図１の無線通信システムと比較すると、基地局１１の配下に移動局３をさらに備える点が異なっている。本実施の形態では、前述した実施の形態１と異なる処理について説明する。 FIG. 5 is a diagram illustrating a configuration example of a second embodiment of the wireless communication system capable of realizing the communication control method according to the present invention. The wireless communication system in FIG. 5 is different from the wireless communication system in FIG. 1 in that the mobile station 3 is further provided under the base station 11. In the present embodiment, processing different from that of the first embodiment will be described.

以下、上記のように構成された無線通信システムにおける干渉発生時の動作を、本実施の形態の特徴的な処理を中心に説明する。本実施の形態では、前述した実施の形態１同様、基地局１２が、移動局１によるオーバーリーチ干渉の発生を検出し、制御装置１０を介して基地局１１に干渉検知通知３２を通知すること、を前提とする。 Hereinafter, an operation at the time of occurrence of interference in the wireless communication system configured as described above will be described focusing on characteristic processing of the present embodiment. In the present embodiment, as in the first embodiment described above, the base station 12 detects the occurrence of overreach interference by the mobile station 1 and notifies the base station 11 of the interference detection notification 32 via the control device 10. Assuming that

干渉検知通知３２を受け取った基地局１１は、干渉発生情報４１を自局配下の移動局（移動局１，３）にブロードキャストする。そして、干渉発生情報４１を受信した移動局１，３は、その応答として、それぞれ干渉発生通知４２，４３を送信する。このとき、実施の形態１と同じように、移動局１が送信する干渉発生通知４２は、干渉発生通知４２ａとして基地局１２にも送信される。 Receiving the interference detection notification 32, the base station 11 broadcasts the interference occurrence information 41 to the mobile stations (mobile stations 1 and 3) under its control. The mobile stations 1 and 3 that have received the interference occurrence information 41 transmit interference occurrence notifications 42 and 43, respectively, as responses. At this time, as in the first embodiment, the interference occurrence notification 42 transmitted by the mobile station 1 is also transmitted to the base station 12 as the interference occurrence notification 42a.

一方で、たとえば、移動局１および３が同時に干渉発生通知を送信した場合には、基地局１１への干渉発生通知４２，４３が互いに干渉する可能性がある。具体的には、ＴＤＭＡ方式では、移動局は、基地局からの不定期なイベントに対して、ランダム遅延発生後に応答を返すことが一般的である。ランダム遅延発生後に干渉発生通知を送信することにより、干渉発生通知同士の干渉はある程度回避可能である。さらに言えば、ランダム遅延を移動局毎に固定的に決めておけば、干渉は完全に回避できる。しかしながら、ランダム遅延を移動局毎に固定的に決めておく方式を採用した場合には、移動局の追加，削除，変更等があった場合でも各移動局から通知が衝突しないように、配下の全移動局を統括管理する必要がある。すなわち、基地局への通知にランダム遅延を導入する場合は、ある程度の干渉が発生すること、または複雑な管理が必要であること、のいずれかを許容しなければならない。 On the other hand, for example, when the mobile stations 1 and 3 transmit the interference occurrence notification at the same time, the interference occurrence notifications 42 and 43 to the base station 11 may interfere with each other. Specifically, in the TDMA scheme, the mobile station generally returns a response to a random event from the base station after a random delay occurs. By transmitting the interference occurrence notification after the random delay occurs, interference between the interference occurrence notifications can be avoided to some extent. Furthermore, interference can be completely avoided if the random delay is fixedly determined for each mobile station. However, when a system in which a random delay is fixedly determined for each mobile station is adopted, even if a mobile station is added, deleted, changed, etc., subordinates are notified so that notifications from each mobile station do not collide. It is necessary to manage all mobile stations. That is, when a random delay is introduced into the notification to the base station, it must be allowed that either some degree of interference occurs or complicated management is required.

なお、オーバーリーチ干渉元の移動局が１つの場合、基地局１２は、干渉発生通知４２ａを正常に受信することができる。また、基地局１２では、実施の形態１と同様に、干渉発生通知４２ａを受信した時点で、オーバーリーチ干渉を発生させた移動局が移動局１であることを特定することができる。 When there is one overreach interference source mobile station, the base station 12 can normally receive the interference occurrence notification 42a. Similarly to the first embodiment, the base station 12 can specify that the mobile station that has generated the overreach interference is the mobile station 1 when the interference occurrence notification 42a is received.

図６は、基地局１２が干渉発生通知４２ａを受信した後の動作を示す図である。干渉発生通知４２ａを受信した基地局１２は、移動局１が干渉発生元であることを示す情報を含んだ特定移動局干渉検知通知３３を制御装置１０に送信し、さらに、制御装置１０は、特定移動局干渉検知通知３３と同一の情報である特定移動局干渉検知通知３４を基地局１１に送信する。そして、特定移動局干渉検知通知３４を受信した基地局１１は、さらに、移動局１を指定して（移動局１の識別子を含めて）特定移動局干渉発生情報４５を自局配下の全移動局にブロードキャストする。 FIG. 6 is a diagram illustrating an operation after the base station 12 receives the interference occurrence notification 42a. The base station 12 that has received the interference occurrence notification 42a transmits a specific mobile station interference detection notification 33 including information indicating that the mobile station 1 is the interference occurrence source to the control device 10, and the control device 10 A specific mobile station interference detection notification 34 that is the same information as the specific mobile station interference detection notification 33 is transmitted to the base station 11. Then, the base station 11 that has received the specific mobile station interference detection notification 34 further designates the mobile station 1 (including the identifier of the mobile station 1) and transmits the specific mobile station interference occurrence information 45 to all the mobiles under its control. Broadcast to the station.

たとえば、特定移動局干渉発生情報４５を受信した移動局３は、その情報に自身の情報が含まれていないと判断し、これを廃棄する。一方で、移動局１は、受信した情報に自身の情報が含まれているので、自局の識別子を含む特定移動局干渉発生通知４６を基地局１１に送信する。このとき、基地局１２では、特定移動局干渉発生通知４６を特定移動局干渉発生通知４６ａとして受信することができる。 For example, the mobile station 3 that has received the specific mobile station interference occurrence information 45 determines that the information does not include its own information and discards it. On the other hand, since the mobile station 1 includes its own information in the received information, the mobile station 1 transmits a specific mobile station interference occurrence notification 46 including its own identifier to the base station 11. At this time, the base station 12 can receive the specific mobile station interference occurrence notification 46 as the specific mobile station interference occurrence notification 46a.

そして、基地局１１，１２は、それぞれ特定移動局干渉発生通知４６，４６ａを受信したタイミングに基づき、実施の形態１と同様の処理で、スロット割当てを再実行する。 Then, base stations 11 and 12 re-execute slot allocation by the same processing as in the first embodiment based on the timing at which specific mobile station interference occurrence notifications 46 and 46a are received, respectively.

以上説明したように、本実施の形態では、被干渉基地局が、実施の形態１と同様に、干渉発生通知に含まれる基地局識別子に基づいて、オーバーリーチ干渉を発生させた移動局を特定することとした。そして、オーバーリーチ干渉を発生させた移動局の情報が含まれた特定移動局干渉検知通知を妨害基地局に通知することとした。したがって、この時点で、妨害基地局は、オーバーリーチ干渉を発生させた自局配下の移動局を認識することができ、妨害基地局と被干渉基地局との間で、オーバーリーチ干渉を発生させた移動局の情報を共有することができる。また、妨害基地局が、干渉発生元の移動局の情報を含めた特定移動局干渉発生情報をブロードキャストし、干渉発生元の移動局のみが、特定移動局干渉発生通知を返信することとした。これにより、妨害基地局および被干渉基地局が、それぞれ特定移動局干渉発生通知のタイミングに基づき、確実に干渉を回避することが可能なスロット割当てを行うことができる。 As described above, in the present embodiment, the interfered base station specifies the mobile station that has caused the overreach interference based on the base station identifier included in the interference occurrence notification, as in the first embodiment. It was decided to. Then, the specific mobile station interference detection notification including the information of the mobile station that has caused the overreach interference is notified to the interfering base station. Therefore, at this point, the interfering base station can recognize the mobile station under its control that caused the overreach interference, and the overreach interference is generated between the interfering base station and the interfered base station. Can share information on mobile stations. Further, the interfering base station broadcasts specific mobile station interference occurrence information including information on the interference generating source mobile station, and only the interference generating source mobile station returns a specific mobile station interference occurrence notification. Thereby, the disturbing base station and the interfered base station can perform slot allocation that can reliably avoid interference based on the timing of the specific mobile station interference occurrence notification.

また、本実施の形態では、干渉発生情報をブロードキャストする基地局が、自局配下の全移動局から干渉発生通知を受信する場合であっても、ランダム遅延の設定により、干渉発生通知同士の干渉を確実に回避することができる。 Further, in this embodiment, even when the base station that broadcasts interference occurrence information receives interference occurrence notifications from all mobile stations under its control, interference between interference occurrence notifications can be determined by setting a random delay. Can be reliably avoided.

実施の形態３．
実施の形態１および２では、オーバーリーチ干渉を発生させる移動局が一つの場合について説明した。本実施の形態では、オーバーリーチ干渉を発生させる移動局が複数の場合について説明する。 Embodiment 3 FIG.
Embodiments 1 and 2 have described the case where there is one mobile station that generates overreach interference. In the present embodiment, a case will be described in which there are a plurality of mobile stations that generate overreach interference.

図７は、本発明にかかる通信制御方法を実現可能な無線通信システムの実施の形態３の構成例を示す図である。図７の無線通信システムは、図１の無線通信システムと比較すると、基地局１２に隣接する基地局１３と、その配下に移動局４とをさらに備える点が異なっている。基地局１３は、基地局１１および１２と同様、制御装置１０と接続されている。また、基地局１３は移動局４と通信中とする。本実施の形態では、前述した実施の形態１と異なる処理について説明する。 FIG. 7 is a diagram illustrating a configuration example of a third embodiment of the wireless communication system capable of realizing the communication control method according to the present invention. The wireless communication system in FIG. 7 is different from the wireless communication system in FIG. 1 in that the wireless communication system further includes a base station 13 adjacent to the base station 12 and a mobile station 4 under its control. The base station 13 is connected to the control device 10 in the same manner as the base stations 11 and 12. The base station 13 is in communication with the mobile station 4. In the present embodiment, processing different from that of the first embodiment will be described.

以下、上記のように構成された無線通信システムにおける干渉発生時の動作を、本実施の形態の特徴的な処理を中心に説明する。本実施の形態では、基地局１２が、移動局１および移動局４によるオーバーリーチ干渉の発生を検出し、制御装置１０を介して、基地局１１および基地局１３に干渉検知通知３２を通知する。 Hereinafter, an operation at the time of occurrence of interference in the wireless communication system configured as described above will be described focusing on characteristic processing of the present embodiment. In the present embodiment, base station 12 detects the occurrence of overreach interference by mobile station 1 and mobile station 4, and notifies interference detection notification 32 to base station 11 and base station 13 via control device 10. .

干渉検知通知３２を受け取った基地局１３は、干渉発生情報４１を自局配下の移動局４に送信し、移動局４は、干渉発生通知４８を基地局１３に送信する。なお、干渉発生通知４８は、干渉発生通知４８ａとして基地局１２においても受信される。 The base station 13 that has received the interference detection notification 32 transmits interference occurrence information 41 to the mobile station 4 under its control, and the mobile station 4 transmits an interference occurrence notification 48 to the base station 13. The interference occurrence notification 48 is also received by the base station 12 as the interference occurrence notification 48a.

たとえば、移動局１と移動局４のＵＰＬＩＮＫデータがほぼ同時に、基地局１２配下の移動局２が送信するＵＰＬＩＮＫデータに対するオーバーリーチ干渉となった場合、基地局１２は、干渉検出通知３１を送信する。その後、各基地局は、制御装置１０経由で干渉検出通知３２を受信すると、実施の形態１と同様に、自局配下の移動局との間で所定の処理を行う。このとき、基地局１２は、移動局１からの干渉発生通知４２ａ、および移動局４からの干渉発生通知４８ａを受信する。以降、各基地局は、実施の形態１の同様の処理で、干渉を回避可能な一定間隔（時定数）で配下の移動局に対してスロット割当てを行う。 For example, when the UPLINK data of the mobile station 1 and the mobile station 4 become almost simultaneously interference with the UPLINK data transmitted from the mobile station 2 under the base station 12, the base station 12 transmits the interference detection notification 31. . Thereafter, when each base station receives the interference detection notification 32 via the control device 10, similarly to the first embodiment, each base station performs a predetermined process with the mobile station under its control. At this time, the base station 12 receives the interference occurrence notification 42 a from the mobile station 1 and the interference occurrence notification 48 a from the mobile station 4. Thereafter, each base station assigns slots to subordinate mobile stations at a constant interval (time constant) that can avoid interference by the same processing as in the first embodiment.

また、干渉発生通知４２ａと４８ａとの間で干渉が発生した場合、基地局１２は、それらの干渉発生通知を正常に受信できない可能性がある。したがって、本実施の形態では、基地局１２が、各装置の処理遅延，伝搬遅延，各移動局のランダム遅延等を考慮したうえで、一定時間が経過しても干渉発生通知を受信できなければ、干渉検出通知３１を再送する。 When interference occurs between the interference occurrence notifications 42a and 48a, the base station 12 may not be able to normally receive the interference occurrence notifications. Therefore, in the present embodiment, the base station 12 is not able to receive an interference occurrence notification even after a certain period of time, taking into account the processing delay, propagation delay of each device, random delay of each mobile station, and the like. The interference detection notification 31 is retransmitted.

以上説明したように、本実施の形態では、オーバーリーチ干渉を発生させる移動局が複数の場合であっても、前述した実施の形態１と同様の効果を得ることができる。また、複数の隣接する基地局配下の移動局に起因するオーバーリーチ干渉によって、干渉発生通知同士が干渉し、干渉を検出した基地局において干渉発生通知が正常受信できなかった場合に、この干渉を検出した基地局が、干渉検出通知を再送する構成とした。これにより、干渉発生通知同士の干渉が回避可能となる。 As described above, in the present embodiment, even when there are a plurality of mobile stations that generate overreach interference, it is possible to obtain the same effect as in the first embodiment. In addition, when the interference occurrence notifications interfere with each other due to over-reach interference caused by a plurality of mobile stations subordinate to the base station, the interference occurrence notification cannot be normally received at the base station that detected the interference. The detected base station retransmits the interference detection notification. As a result, interference between the notifications of occurrence of interference can be avoided.

実施の形態４．
実施の形態１〜３では、移動局によるオーバーリーチ干渉を回避するための処理について説明した。本実施の形態では、オーバーリーチ干渉発生元の移動局が干渉区域から離脱した場合の処理について説明する。 Embodiment 4 FIG.
In the first to third embodiments, the processing for avoiding overreach interference by the mobile station has been described. In the present embodiment, processing when a mobile station that has generated overreach interference leaves the interference area will be described.

図８は、本発明にかかる通信制御方法を実現可能な無線通信システムの実施の形態４の構成例を示す図である。図８の無線通信システムは、図１の無線通信システムと同じ構成であるため説明は省略する。ここで、５０は、オーバーリーチ干渉を発生させる可能性のある干渉区域である。本実施の形態では、前述した実施の形態１〜３と異なる処理について説明する。 FIG. 8 is a diagram illustrating a configuration example of a fourth embodiment of the wireless communication system capable of realizing the communication control method according to the present invention. The radio communication system of FIG. 8 has the same configuration as the radio communication system of FIG. Here, reference numeral 50 denotes an interference area that may cause overreach interference. In the present embodiment, processing different from those of the first to third embodiments will be described.

以下、上記のように構成された無線通信システムにおいて、移動局１が干渉区域５０から離脱した場合の動作について説明する。 Hereinafter, the operation when the mobile station 1 leaves the interference zone 50 in the wireless communication system configured as described above will be described.

まず、移動局１が、干渉区域５０から離脱し、基地局１２の配下への進入した場合の、位置登録および位置登録解除の仕組みを、図８の構成を用いて説明する。移動局１は、基地局から受信する基地局識別子が変化したことで、自身が干渉区域５０から離脱して基地局１２の配下へ進入したことを認識し、このタイミングで位置登録要求を基地局１２に送信する。そして、基地局１２は、制御装置１０経由でまたは直接、基地局１１へ移動局１の位置登録解除を通知し、実施の形態１〜３において実行していた一定間隔のスロット割当てを解除する。 First, the mechanism of location registration and location registration cancellation when the mobile station 1 leaves the interference zone 50 and enters the base station 12 will be described with reference to the configuration of FIG. The mobile station 1 recognizes that it has left the interference zone 50 and entered under the base station 12 due to a change in the base station identifier received from the base station, and issues a location registration request at this timing. 12 to send. Then, the base station 12 notifies the base station 11 of the cancellation of the location registration of the mobile station 1 via the control device 10 or directly, and cancels the slot allocation at regular intervals that has been executed in the first to third embodiments.

つづいて、移動局１が、干渉区域５０から離脱し、再度基地局１１配下のオーバーリーチ干渉とならないエリアに移動した場合の動作を、図８の構成を用いて説明する。たとえば、移動局１が、干渉区域５０から離脱し、再度基地局１１配下のオーバーリーチ干渉とならないエリアに移動した直後、スロット割当ての状況は、図４のようになっている。 Next, the operation when the mobile station 1 leaves the interference zone 50 and moves again to an area that does not cause overreach interference under the base station 11 will be described using the configuration of FIG. For example, immediately after the mobile station 1 leaves the interference zone 50 and moves again to an area that does not cause overreach interference under the base station 11, the slot assignment status is as shown in FIG.

たとえば、移動局１は、干渉区域５０に位置している場合は、基地局１１との間で“１”がセットされている左から２，５番目のタイミングで、ＵＰＬＩＮＫデータを送信する。一方、基地局１２は、移動局１によるオーバーリーチ干渉によって、基地局１２が移動局２に対してスロットを割当てていない“−”がセットされている左から２，５番目のタイミングで、移動局１からのＵＰＬＩＮＫデータを受信することになる。そして、基地局１２は、受信したＵＰＬＩＮＫデータに含まれた基地局１１の基地局識別子を検出することにより、このデータが基地局１１配下の移動局からのデータであることを認識することができる。 For example, when the mobile station 1 is located in the interference zone 50, the mobile station 1 transmits UPLINK data at the second and fifth timings from the left at which "1" is set with the base station 11. On the other hand, the base station 12 moves at the second and fifth timings from the left when the base station 12 is set to “−” in which no slot is allocated to the mobile station 2 due to the overreach interference by the mobile station 1. The UPLINK data from the station 1 will be received. Then, the base station 12 can recognize that this data is data from a mobile station under the base station 11 by detecting the base station identifier of the base station 11 included in the received UPLINK data. .

しかしながら、移動局１が干渉区域５０から離脱し、オーバーリーチ干渉とならないエリアへ進入すると、基地局１２は、上述した“−”がセットされている左から２，５番目のタイミングで何も受信しなくなる。したがって、干渉区域５０と外部区域との間の、微少時間の進入／離脱を考慮し、移動局１からのＵＰＬＩＮＫデータを一定時間受信しなければ、移動局１が干渉区域５０から離脱し、オーバーリーチ干渉とならないエリアへ進入したものとみなすことができる。基地局１２は、上記離脱および進入を認識した時点で、制御装置１０経由でまたは直接、基地局１１へ干渉解除通知（３５，３６）を送信する。干渉解除通知は、移動局が移動したことにより、干渉を生じさせていた原因が除かれたことを通知するための信号である。 However, when the mobile station 1 leaves the interference zone 50 and enters an area where overreach interference does not occur, the base station 12 receives nothing at the second and fifth timings from the left where “−” is set. No longer. Therefore, in consideration of a very short time entry / exit between the interference area 50 and the external area, if the UPLINK data from the mobile station 1 is not received for a certain period of time, the mobile station 1 leaves the interference area 50 and is overloaded. It can be considered that the vehicle has entered an area that does not cause reach interference. When the base station 12 recognizes the departure and entry, the base station 12 transmits an interference cancellation notification (35, 36) to the base station 11 via the control device 10 or directly. The interference cancellation notification is a signal for notifying that the cause of the interference has been removed due to the movement of the mobile station.

そして、基地局１２は干渉解除通知３５を送信したタイミングで、基地局１１は干渉解除通知３６を受信したタイミングで、それぞれ前述した実施の形態で実行した一定間隔のスロット割当てを解除し、たとえば、図２のようなオーバーリーチ干渉を前提としないスロット割当てを実行する。 Then, at the timing when the base station 12 transmits the interference cancellation notification 35 and at the timing when the base station 11 receives the interference cancellation notification 36, the slot allocation at regular intervals performed in the above-described embodiment is canceled, for example, Slot allocation that does not assume overreach interference as shown in FIG. 2 is executed.

以上説明したように、本実施の形態では、移動局１が干渉区域５０から離脱し、オーバーリーチ干渉とならないエリアへ進入した場合に、移動局１を収容する基地局１１に対して干渉解除通知を送信し、通常のスロット割当てを実行することとした。これにより、オーバーリーチ干渉が発生していない状態での効率のよいスロット割当てが実行可能となるので、無線リソースの有効利用が可能となる。 As described above, in the present embodiment, when the mobile station 1 leaves the interference zone 50 and enters an area that does not cause overreach interference, the base station 11 that accommodates the mobile station 1 is notified of interference cancellation. And the normal slot assignment is executed. As a result, efficient slot allocation can be performed in a state where no overreach interference occurs, so that radio resources can be effectively used.

実施の形態５．
実施の形態１〜４では、基地局がオーバーリーチ干渉の検出を行う場合について説明した。本実施の形態では、移動局が自分の位置情報を検知して干渉発生通知を基地局に送信する場合について説明する。 Embodiment 5 FIG.
In the first to fourth embodiments, the case where the base station detects overreach interference has been described. In this embodiment, a case will be described in which a mobile station detects its own location information and transmits an interference occurrence notification to a base station.

図９は、本発明にかかる通信制御方法を実現可能な無線通信システムの実施の形態５の構成例を示す図である。なお、本実施の形態では、図９の無線通信システムが列車無線通信システムであることを前提として説明するが、構成は図８の無線通信システムと同じである。本実施の形態では、前述した実施の形態１〜４と異なる処理について説明する。 FIG. 9 is a diagram illustrating a configuration example of a fifth embodiment of the wireless communication system capable of realizing the communication control method according to the present invention. In addition, although this Embodiment demonstrates on the assumption that the radio | wireless communications system of FIG. 9 is a train radio | wireless communications system, a structure is the same as the radio | wireless communications system of FIG. In the present embodiment, processing different from that in the first to fourth embodiments will be described.

列車無線通信システムでは、列車（移動局）は、自身の起点からの位置を、キロ程という距離情報で正確に把握可能である。そこで、移動局は、干渉区域５０についてのキロ程を予め設定しておく。これにより、移動局は、干渉区域５０内に位置していることを自律的に検出することができるため、干渉発生通知４３および４３ａを基地局１１および基地局１２へ送信することができる。 In a train radio communication system, a train (mobile station) can accurately grasp the position from its starting point with distance information of about a kilometer. Therefore, the mobile station sets a kilometer about the interference area 50 in advance. Thereby, since the mobile station can autonomously detect that it is located in the interference zone 50, it is possible to transmit the interference occurrence notifications 43 and 43a to the base station 11 and the base station 12.

以上説明したように、本実施の形態では、列車無線通信システムを一例として、予め干渉区域の位置を列車（移動局）に設定し、干渉区域に入ったことを検知した列車が、各基地局に干渉発生通知を送信することとした。これにより、基地局におけるオーバーリーチ干渉の検出処理や干渉発生通知の送信処理が不要となるので、オーバーリーチ干渉を回避する場合の基地局での処理を簡素化できる。 As described above, in the present embodiment, the train radio communication system is taken as an example, the position of the interference area is set in the train (mobile station) in advance, and the train that has detected that it has entered the interference area is connected to each base station. An interference occurrence notification is sent to This eliminates the need for overreach interference detection processing and interference occurrence notification transmission processing in the base station, and thus simplifies the processing in the base station when avoiding overreach interference.

以上のように、本発明にかかる通信制御方法は、オーバーリーチ干渉が発生する無線通信システムに有用であり、特に、オーバーリーチ干渉が発生した場合に当該干渉を高い精度で回避する方法として適している。 As described above, the communication control method according to the present invention is useful for a radio communication system in which overreach interference occurs, and is particularly suitable as a method for avoiding the interference with high accuracy when overreach interference occurs. Yes.

本発明にかかる通信制御方法を実現可能な無線通信システムの実施の形態１の構成例を示す図である。It is a figure which shows the structural example of Embodiment 1 of the radio | wireless communications system which can implement | achieve the communication control method concerning this invention. 基地局における移動局に対するスロット割当て例を示す図である。It is a figure which shows the example of slot allocation with respect to the mobile station in a base station. 基地局が干渉検出通知を受信した後の動作を示す図である。It is a figure which shows the operation | movement after a base station receives the interference detection notification. 基地局による、干渉発生後の移動局に対するスロット割当ての一例を示す図である。It is a figure which shows an example of the slot allocation with respect to the mobile station after interference generation by the base station. 本発明にかかる通信制御方法を実現可能な無線通信システムの実施の形態２の構成例を示す図である。It is a figure which shows the structural example of Embodiment 2 of the radio | wireless communications system which can implement | achieve the communication control method concerning this invention. 基地局が干渉発生通知を受信した後の動作を示す図である。It is a figure which shows the operation | movement after a base station receives the notification of interference occurrence. 本発明にかかる通信制御方法を実現可能な無線通信システムの実施の形態３の構成例を示す図である。It is a figure which shows the structural example of Embodiment 3 of the radio | wireless communications system which can implement | achieve the communication control method concerning this invention. 本発明にかかる通信制御方法を実現可能な無線通信システムの実施の形態４の構成例を示す図である。It is a figure which shows the structural example of Embodiment 4 of the radio | wireless communications system which can implement | achieve the communication control method concerning this invention. 本発明にかかる通信制御方法を実現可能な無線通信システムの実施の形態５の構成例を示す図である。It is a figure which shows the structural example of Embodiment 5 of the radio | wireless communications system which can implement | achieve the communication control method concerning this invention.

Explanation of symbols

１，２移動局
１０制御装置
１１，１２，１３基地局
２１，２２ＵＰＬＩＮＫデータ
３１，３２干渉検出通知
４１干渉発生情報
４２，４２ａ，４３，４３ａ干渉発生通知
３３，３４特定移動局干渉検知通知
３５，３６干渉解除通知
４５特定移動局干渉発生情報
４６，４６ａ特定移動局干渉発生通知
４８，４８ａ干渉発生通知
５０干渉区域 1, 2 Mobile station 10 Control device 11, 12, 13 Base station 21, 22 UPLINK data 31, 32 Interference detection notification 41 Interference occurrence information 42, 42a, 43, 43a Interference occurrence notification 33, 34 Specific mobile station interference detection notification 35 , 36 Interference cancellation notification 45 Specific mobile station interference occurrence information 46, 46a Specific mobile station interference occurrence notification 48, 48a Interference occurrence notification 50 Interference area

Claims

In a wireless communication system employing the TDMA scheme, uplink data transmitted from a specific mobile station communicating with the first base station becomes overreach interference, and the second base station receives the uplink data normally. Communication control method when
An interference detection step in which the second base station detects the occurrence of the interference;
An interference detection notification step in which the second base station transmits an interference detection notification for notifying detection of overreach interference to the first base station;
The first base station that has received the interference detection notification transmits interference occurrence information including the identifier of the own station to a mobile station under its own station,
The specific mobile station that has received the interference occurrence information receives, as a response, an interference occurrence notification that includes the identifier of the local station and the identifier of the first base station included in the interference occurrence information. An interference occurrence notification transmission step to be transmitted to the base station;
Based on the timing at which the first base station that has received the notification of occurrence of interference and the second base station that has received the notification of occurrence of interference by overreach receive the notification, slots to be used do not overlap between the base stations. A slot assignment step for performing slot assignment for subordinate mobile stations,
The communication control method characterized by including.

In a wireless communication system employing the TDMA scheme, uplink data transmitted from a specific mobile station communicating with the first base station becomes overreach interference, and the second base station receives the uplink data normally. Communication control method when
An interference detection step in which the second base station detects the occurrence of the interference;
An interference detection notification step in which the second base station transmits an interference detection notification for notifying detection of overreach interference to the first base station;
The first base station that has received the interference detection notification transmits interference occurrence information including the identifier of the own station to a mobile station under its own station,
As a response, all the mobile stations that have received the interference occurrence information send an interference occurrence notification including the identifier of the local station and the identifier of the first base station included in the interference occurrence information to the first base station. An interference occurrence notification transmission step to be transmitted to the station;
The second base station that has received the interference occurrence notification transmitted by the specific mobile station by overreach sends the specific mobile station interference detection notification including the identifier of the specific mobile station to the first base station. Specific mobile station interference detection notification step to send to,
The first base station that has received the specific mobile station interference detection notification transmits the specific mobile station interference occurrence information including the identifier of the specific mobile station to the mobile station under its own station. Station interference occurrence information transmission step;
As a response, the specific mobile station whose own mobile station interference occurrence information is included in the received specific mobile station interference occurrence information sends a specific mobile station interference occurrence notification including the local station identifier as the first base station. Specific mobile station interference occurrence notification transmission step to be transmitted to,
Based on the timing at which the first base station that has received the specific mobile station interference occurrence notification and the second base station that has received the specific mobile station interference occurrence notification by overreach have received the notification, there is a slot to use. A slot assignment step for performing slot assignment for subordinate mobile stations so as not to overlap between base stations;
The communication control method characterized by including.

In the specific mobile station interference occurrence notification transmission step,
3. The communication control method according to claim 2, wherein a mobile station other than the specific mobile station, which does not include an identifier of the local station in received specific mobile station interference occurrence information, discards the received information. .

Based on the identifier included in the interference occurrence notification, the second base station that has received the interference occurrence notification by the overreach, the mobile station that has generated the overreach interference causes the specific base station under the first base station to The communication control method according to claim 1, wherein the communication control method recognizes a mobile station.

The second base station that has transmitted the interference detection notification retransmits the interference detection notification when it has not received the interference occurrence notification for a certain period of time. Communication control method.

The second base station is
After performing the slot allocation step, if uplink data from the specific mobile station due to overreach cannot be received for a certain period of time, the specific mobile station moves from an area that causes overreach interference to an area that does not cause overreach interference. And notify the first base station to that effect,
Thereafter, the first base station and the second base station are:
The communication control method according to claim 1, wherein the slot assignment to a subordinate mobile station is returned to the assignment before the execution of the slot assignment step.

In a wireless communication system employing the TDMA scheme, an area where all mobile stations cause overreach interference is stored in advance, and uplink data transmitted by a specific mobile station in communication with the first base station A communication control method in the case where overreach interference occurs and the second base station cannot normally receive uplink data,
When it is detected that the specific mobile station is located in the area, an area detection notification for notifying the fact is transmitted to the first base station and the second base station. An area detection notification step;
The first base station and the second base station that have received the area detection notification execute slot allocation to subordinate mobile stations based on the timing at which the notification is received so that slots to be used do not overlap between base stations. Slot assignment step,
The communication control method characterized by including.

In the slot allocation step,
One of the first base station and the second base station performs slot allocation to a mobile station under its own station at the reception timing,
The communication control method according to any one of claims 1 to 7, wherein the other base station executes slot assignment to a mobile station under its control at a timing next to the reception timing.

In the slot allocation step,
Each base station periodically performs slot allocation to mobile stations under its own base at regular intervals based on a common time constant so that slots to be used do not overlap between base stations The communication control method according to any one of claims 1 to 8.