JP2010283543A

JP2010283543A - Route switching method and relay station

Info

Publication number: JP2010283543A
Application number: JP2009134499A
Authority: JP
Inventors: Yuya Takatsuka; 雄也高塚
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2009-06-03
Filing date: 2009-06-03
Publication date: 2010-12-16

Abstract

【課題】パケット中継経路の経路切替方法を得ること。
【解決手段】マルチホップセルラネットワークにおけるパケット中継経路の経路切替方法であって、移動局から接続要求を受信した特定の中継局が、当該移動局に対して割り当て可能なリソースが存在するかどうかを確認し、リソースが足りない場合、自局で中継しているパケットを異なる中継局で中継してもらうための経路変更要求を送信する経路変更要求ステップと、経路変更要求に基づいて、特定の中継局以外の装置が、前記パケットの中継経路を特定の中継局を含まない経路に切り替える処理を行い、その後、経路変更要求送信元の特定の中継局に対して経路変更完了通知を送信する経路変更切替ステップと、経路変更完了通知を受信した特定の中継局が、接続要求送信元の移動局に対してリソースを割り当てリソース割当ステップと、を含む。
【選択図】図４A route switching method for a packet relay route is provided.
A method for switching a packet relay path in a multi-hop cellular network, in which whether a specific relay station that has received a connection request from a mobile station has a resource that can be allocated to the mobile station exists. If there is not enough resources, a route change request step for sending a route change request for relaying a packet relayed by the own station to a different relay station and a specific relay based on the route change request A route change in which a device other than the station performs a process of switching the relay route of the packet to a route that does not include a specific relay station, and then transmits a route change completion notification to the specific relay station that is the source of the route change request The switching step and the specific relay station that has received the route change completion notification assigns resources to the mobile station that is the connection request transmission source. , Including the.
[Selection] Figure 4

Description

本発明は、マルチホップセルラネットワークにおけるパケット中継経路の経路切替方法に関する。 The present invention relates to a route switching method for a packet relay route in a multi-hop cellular network.

従来、セルラネットワークにおいて、コアネットワークと接続する基地局と移動端末との間に中継局を設置してマルチホップ通信を行うマルチホップセルラネットワークシステムが広く研究されている。マルチホップセルラネットワークでは、中継局がパケットを中継しているが、複数の移動端末や他の中継局からのパケットを中継すると、中継局においてリソースが減少する。すなわち、中継局では、中継するパケットの量が増加すると、自局に接続する移動端末へ十分なリソースを提供することができなくなる、という問題があった。 Conventionally, in a cellular network, a multi-hop cellular network system that performs multi-hop communication by installing a relay station between a base station connected to a core network and a mobile terminal has been widely studied. In a multihop cellular network, a relay station relays a packet. However, when packets from a plurality of mobile terminals and other relay stations are relayed, resources are reduced in the relay station. In other words, the relay station has a problem that if the amount of packets to be relayed increases, sufficient resources cannot be provided to the mobile terminal connected to the local station.

また、中継局におけるリソース不足は、アドホックネットワークでも発生する問題である。下記特許文献１には、中継局においてデータ処理に要するリソースが不足した場合に、送信端末へ中継データの送信量を制限させる制御メッセージを送信することにより、中継データ量を制御する技術が開示されている。 In addition, a shortage of resources in the relay station is a problem that also occurs in ad hoc networks. Patent Document 1 below discloses a technique for controlling the amount of relay data by transmitting a control message for limiting the amount of relay data to be transmitted to a transmission terminal when resources required for data processing are insufficient in the relay station. ing.

また、リソースを確保する方法として、下記特許文献２には、基地局におけるリソースが不足した場合に、利用頻度の低いユーザが使用する高レートチャネルを低レートチャネルへ割り当て直し、利用頻度の高いユーザや有料でも高レートの通信を求めるユーザに対し、高レートのチャネルを割り当てる技術が開示されている。 In addition, as a method for securing resources, the following Patent Document 2 describes that, when resources in a base station are insufficient, a high-rate channel used by a low-use user is reassigned to a low-rate channel, and a high-use user In addition, a technique for allocating a high-rate channel to a user who demands high-rate communication even for a fee is disclosed.

特開２００６−５０３７１号公報JP 2006-50371 A 特開２００７−１０４２８２号公報JP 2007-104282 A

しかしながら、上記特許文献１の技術によれば、中継局の負荷を軽減するために送信元のパケット量を制限してしまう、という問題があった。また、上記特許文献２の技術によれば、利用頻度等によりレートが異なるチャネルを割り当てるため、マルチホップセルラネットワークにおける制御負荷が増加し制御が複雑化する、という問題があった。 However, according to the technique disclosed in Patent Document 1, there is a problem that the amount of packets at the transmission source is limited in order to reduce the load on the relay station. Further, according to the technique of the above-mentioned Patent Document 2, since channels having different rates are allocated depending on the usage frequency and the like, there is a problem that the control load in the multihop cellular network increases and the control becomes complicated.

本発明は、上記に鑑みてなされたものであって、送信元のパケット量を制限することなく、かつ、制御負荷を増加させることなく、新規接続の無線移動局に対して必要なリソースを割り当てることが可能なパケット中継経路の経路切替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 allocates necessary resources to a newly connected radio mobile station without limiting the amount of packets at the transmission source and without increasing the control load. It is an object of the present invention to obtain a route switching method for a packet relay route that can be used.

上述した課題を解決し、目的を達成するために、本発明は、マルチホップセルラネットワークにおけるパケット中継経路の経路切替方法であって、移動局から接続要求を受信した中継局である特定の中継局が、当該移動局に対して割り当て可能なリソースが存在するかどうかを確認し、リソースが足りない場合、自局で中継しているパケットを異なる中継局で中継してもらうための経路変更要求を送信する経路変更要求ステップと、前記経路変更要求に基づいて、前記特定の中継局以外の装置が、前記パケットの中継経路を前記特定の中継局を含まない経路に切り替える処理を行い、その後、経路変更要求送信元の前記特定の中継局に対して経路変更完了通知を送信する経路変更切替ステップと、前記経路変更完了通知を受信した前記特定の中継局が、接続要求送信元の移動局に対してリソースを割り当てるリソース割当ステップと、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 packet switching route switching method in a multi-hop cellular network, and a specific relay station that is a relay station that has received a connection request from a mobile station However, if there is not enough resources to check if there is a resource that can be allocated to the mobile station, a route change request for receiving a packet relayed by the local station at a different relay station is issued. Based on the route change request step to be transmitted and the route change request, a device other than the specific relay station performs a process of switching the relay route of the packet to a route that does not include the specific relay station. A route change switching step for transmitting a route change completion notification to the specific relay station of the change request transmission source, and the specific change that has received the route change completion notification Tsugikyoku, characterized in that it comprises a resource allocation step of allocating a resource to the connection request transmission source mobile station.

本発明によれば、送信元のパケット量を制限せず、かつ、制御負荷が増加し複雑化することなく、新規接続の移動端末に対して十分なリソースを割り当てることができる、という効果を奏する。 According to the present invention, there is an effect that it is possible to allocate sufficient resources to a newly connected mobile terminal without limiting the amount of packets at the transmission source and without increasing and complicating the control load. .

図１は、マルチホップセルラネットワークの構成例を示す図である。FIG. 1 is a diagram illustrating a configuration example of a multi-hop cellular network. 図２は、無線中継局の構成例を示す図である。FIG. 2 is a diagram illustrating a configuration example of a radio relay station. 図３は、無線移動局の構成例を示す図である。FIG. 3 is a diagram illustrating a configuration example of a wireless mobile station. 図４は、経路切替処理を示すシーケンス図である。FIG. 4 is a sequence diagram showing the route switching process. 図５は、経路切替処理を示すシーケンス図である。FIG. 5 is a sequence diagram showing the route switching process. 図６は、経路切替処理を示すシーケンス図である。FIG. 6 is a sequence diagram showing the route switching process.

以下に、本発明にかかるパケット中継経路の経路切替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 route switching method for packet relay routes 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、本実施の形態におけるパケット中継経路の経路切替方法を実現するマルチホップセルラネットワークの構成例を示す図である。マルチホップセルラネットワークは、無線中継局１〜７と、無線移動局１１〜１３と、から構成されている。無線中継局１〜７は、コアネットワークとの接続インタフェースを持つ図示しないマルチホップセルラゲートウェイと無線移動局１１〜１３との間に配置され、マルチホップセルラゲートウェイから送信されたデータを無線移動局１１〜１３へ転送し、また、無線移動局１１〜１３から送信されたデータをマルチホップセルラゲートウェイへ転送する。無線移動局１１〜１３は、いずれかの無線中継局１〜７へ接続することによりデータ通信を行う。 Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a multi-hop cellular network that realizes a route switching method of a packet relay route according to the present embodiment. The multi-hop cellular network is composed of radio relay stations 1 to 7 and radio mobile stations 11 to 13. The radio relay stations 1 to 7 are arranged between a multi-hop cellular gateway (not shown) having a connection interface with the core network and the radio mobile stations 11 to 13, and transmit data transmitted from the multi-hop cellular gateway to the radio mobile station 11. To 13 and the data transmitted from the wireless mobile stations 11 to 13 are transferred to the multi-hop cellular gateway. The wireless mobile stations 11 to 13 perform data communication by connecting to any one of the wireless relay stations 1 to 7.

例えば、無線移動局１２がパケットを送信した場合、パケットは、無線中継局２から、無線中継局１または無線中継局７を経由して無線中継局６へ転送される。また、無線移動局１３がパケットを送信した場合、パケットは、無線中継局３から、無線中継局１または無線中継局４を経由して無線中継局５へ転送される。 For example, when the wireless mobile station 12 transmits a packet, the packet is transferred from the wireless relay station 2 to the wireless relay station 6 via the wireless relay station 1 or the wireless relay station 7. When the wireless mobile station 13 transmits a packet, the packet is transferred from the wireless relay station 3 to the wireless relay station 5 via the wireless relay station 1 or the wireless relay station 4.

図２は、無線中継局１の構成例を示す図である。無線中継局１は、無線Ｉ／Ｆ部２１と、無線信号中継部２２と、制御メッセージ処理部２３と、経路決定部２４と、リソース管理部２５と、を備える。無線Ｉ／Ｆ部２１は、マルチホップセルラゲートウェイ、無線中継局、無線移動局と接続するインタフェースである。無線信号中継部２２は、受信した他局宛の信号を中継する制御を行う。制御メッセージ処理部２３は、他局から受信した制御メッセージおよび自局から送信する制御メッセージなどの各種制御メッセージを処理する。経路決定部２４は、ルーティング処理を行い、また、無線リソースを確保のための経路切り替えの判断を行う。リソース管理部２５は、パケットの送受信に使用する無線リソースの管理を行う。無線中継局１では、経路決定部２４およびリソース管理部２５において、本実施の形態における経路切替処理を行う。他の構成については従来の無線中継局と同等である。なお、無線中継局２〜７も同様の構成を備える。 FIG. 2 is a diagram illustrating a configuration example of the radio relay station 1. The radio relay station 1 includes a radio I / F unit 21, a radio signal relay unit 22, a control message processing unit 23, a route determination unit 24, and a resource management unit 25. The wireless I / F unit 21 is an interface connected to a multi-hop cellular gateway, a wireless relay station, and a wireless mobile station. The radio signal relay unit 22 performs control to relay the received signal addressed to another station. The control message processing unit 23 processes various control messages such as control messages received from other stations and control messages transmitted from the own station. The route determination unit 24 performs a routing process and determines route switching for securing radio resources. The resource management unit 25 manages radio resources used for packet transmission / reception. In the wireless relay station 1, the route determination unit 24 and the resource management unit 25 perform route switching processing in the present embodiment. Other configurations are the same as those of the conventional radio relay station. The wireless relay stations 2 to 7 have the same configuration.

図３は、無線移動局１１の構成例を示す図である。無線移動局１１は、無線Ｉ／Ｆ部３１と、制御メッセージ処理部３２と、を備える。無線Ｉ／Ｆ部３１は、無線中継局と接続するインタフェースである。制御メッセージ処理部３２は、他局から受信した制御メッセージおよび自局から送信する制御メッセージなどの各種制御メッセージを処理する。これらの構成については従来の無線移動局と同等である。なお、無線移動局１２、１３も同様の構成を備える。 FIG. 3 is a diagram illustrating a configuration example of the wireless mobile station 11. The wireless mobile station 11 includes a wireless I / F unit 31 and a control message processing unit 32. The wireless I / F unit 31 is an interface connected to a wireless relay station. The control message processing unit 32 processes various control messages such as control messages received from other stations and control messages transmitted from the own station. About these structures, it is equivalent to the conventional radio | wireless mobile station. The wireless mobile stations 12 and 13 also have the same configuration.

つづいて、無線中継局がパケット中継の経路を切り替える経路切替処理について説明する。ここでは、無線中継局１に対して無線移動局１１が接続要求した場合を想定する。なお、初期状態として、無線中継局１は、無線中継局２、無線中継局３からのパケット中継にリソースを使用し、新規接続を要求する無線移動局１１へ割り当てるリソースが不足している状態とする。 Next, route switching processing in which the wireless relay station switches the packet relay route will be described. Here, it is assumed that the wireless mobile station 11 makes a connection request to the wireless relay station 1. Note that, as an initial state, the radio relay station 1 uses resources for packet relay from the radio relay station 2 and the radio relay station 3, and there is a shortage of resources allocated to the radio mobile station 11 that requests a new connection. To do.

図４は、無線中継局および無線移動局での経路切替処理を示すシーケンス図である。無線移動局１１から接続要求メッセージＳ１を受信した場合、無線中継局１では、リソース管理部２５で確認した結果、無線移動局１１へ割り当てるリソースが不足している。そのため、無線中継局１は、リソースを確保するため、経路決定部２４が、中継パケットの送信元の無線中継局から１つの無線中継局（ここでは無線中継局２とする）を選択し、無線中継局２へ経路変更要求メッセージＳ２を送信する。 FIG. 4 is a sequence diagram showing route switching processing at the radio relay station and the radio mobile station. When the connection request message S1 is received from the radio mobile station 11, the radio relay station 1 has confirmed that the resource management unit 25 has insufficient resources to be allocated to the radio mobile station 11. Therefore, in the radio relay station 1, the route determination unit 24 selects one radio relay station (herein, the radio relay station 2) from the radio relay station that is the transmission source of the relay packet in order to secure resources, and the radio relay station 1 A route change request message S2 is transmitted to the relay station 2.

経路変更要求メッセージＳ２を受信した無線中継局２は、経路決定部２４が、無線中継局１を経由しない他のルート（例えば、無線中継局２−無線中継局７−無線中継局６）を選択し、無線中継局７へ中継の可否を問い合わせる経路変更確認メッセージＳ３を送信する。 In the wireless relay station 2 that has received the route change request message S2, the route determination unit 24 selects another route that does not pass through the wireless relay station 1 (for example, wireless relay station 2-wireless relay station 7-wireless relay station 6). Then, a route change confirmation message S3 for inquiring whether the relay is possible or not is transmitted to the wireless relay station 7.

経路変更確認メッセージＳ３を受信した無線中継局７では、リソース管理部２５が、割り当て可能なリソースおよび経路決定部２４からの無線中継局６とのリンク状態を確認してから中継の可否を判定し、無線中継局２に対して経路変更応答メッセージＳ４を返信する。可能な場合は、リソース管理部２５でリソースを予約するとともに、無線中継局２に対して可の応答を返信する。不可能な場合は、無線中継局２に対して不可の応答を返信する。ここでは、可能な場合について説明する。 In the radio relay station 7 that has received the route change confirmation message S3, the resource management unit 25 confirms the resources that can be allocated and the link state with the radio relay station 6 from the route determination unit 24, and determines whether or not relaying is possible. Then, a route change response message S4 is returned to the wireless relay station 2. If possible, the resource management unit 25 reserves the resource and returns a possible response to the radio relay station 2. If not possible, an impossible response is returned to the radio relay station 2. Here, a possible case will be described.

無線中継局２は、無線中継局７から受信した経路変更応答メッセージＳ４が可の場合、経路決定部２４が、無線中継局１を経由させていたパケット送信の経路を無線中継局７経由の経路に変更し、無線中継局１に対して経路変更完了メッセージＳ５を返信する。なお、無線中継局２は、無線中継局７から受信した経路変更応答メッセージＳ４が不可の場合、経路決定部２４が、他の経路の無線中継局について同様の中継可否の確認を行う。全ての経路の無線中継局からの経路変更応答メッセージＳ４が不可の場合、無線中継局１に対して経路変更不可メッセージを返信する。 When the route change response message S4 received from the wireless relay station 7 is acceptable, the wireless relay station 2 determines that the route determination unit 24 determines the packet transmission route that has been routed through the wireless relay station 1 as the route via the wireless relay station 7. And a route change completion message S5 is returned to the wireless relay station 1. When the route change response message S4 received from the wireless relay station 7 is not possible, the wireless relay station 2 confirms whether the same relay is possible for the wireless relay stations on other routes. When the route change response message S4 from the wireless relay stations of all routes is not possible, a route change impossible message is returned to the wireless relay station 1.

無線中継局１は、経路変更完了メッセージＳ５を受信した場合、リソース管理部２５で無線移動局１１へリソースを割り当てた後、経路決定部２４が無線移動局１１に対して接続完了メッセージＳ６を返信する。なお、無線中継局１は、経路変更不可メッセージを受信した場合、経路決定部２４が、他の中継パケットの送信元である無線中継局３に対して経路変更要求メッセージＳ２を送信する。以降の処理については、無線中継局２に対して経路変更要求メッセージＳ２を送信した場合と同様である。全ての中継パケットの送信元の無線中継局からの返信が不可（経路変更不可メッセージ）であった場合、無線中継局１では、経路決定部２４が無線移動局１１に対して接続拒否メッセージを返信する。 When the wireless relay station 1 receives the route change completion message S5, the resource management unit 25 allocates resources to the wireless mobile station 11, and then the route determination unit 24 returns a connection completion message S6 to the wireless mobile station 11. To do. When the wireless relay station 1 receives the route change impossible message, the route determination unit 24 transmits a route change request message S2 to the wireless relay station 3 that is the transmission source of another relay packet. The subsequent processing is the same as when the route change request message S2 is transmitted to the radio relay station 2. When the reply from the wireless relay station that is the transmission source of all relay packets is not possible (route change impossible message), in the wireless relay station 1, the route determination unit 24 returns a connection rejection message to the wireless mobile station 11. To do.

以上説明したように、本実施の形態では、無線移動局から接続要求を受信した際に無線移動局へ割り当てるリソースが不足する場合、無線中継局は、パケット中継している当該パケットの送信元の無線中継局に対して経路変更を要求し、送信元の無線中継局では、経路の切り替えが可能な場合にパケット送信の経路を変更することとした。これにより、無線移動局から接続要求を受信した無線中継局では、無線移動局へ割り当てるリソースを確保することができる。 As described above, in this embodiment, when a resource to be allocated to a radio mobile station is insufficient when a connection request is received from the radio mobile station, the radio relay station transmits the packet transmission source of the packet being relayed. The wireless relay station is requested to change the route, and the transmission source wireless relay station changes the route of packet transmission when the route can be switched. As a result, the radio relay station that has received the connection request from the radio mobile station can secure resources to be allocated to the radio mobile station.

なお、変更後の経路が２ホップの場合について説明したが、これに限定せず、ホップ数の制限は持たないものとする。また、送信元については無線中継局ではなく無線移動局としてもよく、転送先についても無線中継局ではなくマルチホップセルラゲートウェイとしてもよい。また、中継パケットの送信元の無線中継局からの全中継パケットの経路を変更する場合について説明したが、必要に応じて経路変更する中継パケット量を調整してもよい。 In addition, although the case where the route after the change is 2 hops has been described, it is not limited to this, and it is assumed that there is no limit on the number of hops. The transmission source may be a wireless mobile station instead of the wireless relay station, and the transfer destination may be a multi-hop cellular gateway instead of the wireless relay station. Moreover, although the case where the route of all relay packets from the wireless relay station that is the transmission source of the relay packet is changed has been described, the amount of relay packets whose route is changed may be adjusted as necessary.

実施の形態２．
本実施の形態では、リソースを確保したい無線中継局が、自局に代わってパケット中継を行う無線中継局に対して経路変更要求メッセージを送信する。実施の形態１と異なる部分について説明する。なお、初期状態は実施の形態１と同様とするが、ここでは、各無線中継局が、近隣の無線中継局の位置情報を取得しているものとする。 Embodiment 2. FIG.
In the present embodiment, a radio relay station that wants to secure resources transmits a route change request message to a radio relay station that performs packet relay on behalf of itself. A different part from Embodiment 1 is demonstrated. Although the initial state is the same as that of the first embodiment, it is assumed here that each radio relay station has acquired the position information of neighboring radio relay stations.

図５は、無線中継局および無線移動局での経路切替処理を示すシーケンス図である。無線移動局１１から接続要求メッセージＳ１１を受信した場合、無線中継局１では、リソース管理部２５で確認した結果、無線移動局１１へ割り当てるリソースが不足している。そのため、無線中継局１は、リソースを確保するため、経路決定部２４が、近隣無線中継局の位置情報から無線中継局７が無線中継局２からのパケットを無線中継局６へ中継可能と判断し、無線中継局７へ経路変更要求メッセージＳ１２を送信する。 FIG. 5 is a sequence diagram showing route switching processing at the radio relay station and the radio mobile station. When the connection request message S11 is received from the wireless mobile station 11, the wireless relay station 1 has confirmed that the resource management unit 25 has insufficient resources to be allocated to the wireless mobile station 11. Therefore, in order to secure resources, the radio relay station 1 determines that the route determination unit 24 can relay the packet from the radio relay station 2 to the radio relay station 6 based on the position information of the neighboring radio relay stations. The route change request message S12 is transmitted to the radio relay station 7.

経路変更要求メッセージＳ１２を受信した無線中継局７では、リソース管理部２５が、割り当て可能なリソースおよび経路決定部２４からの無線中継局２および無線中継局６とのリンク状態を確認してから中継の可否を判定する。可能な場合は、リソース管理部２５で各リンク間のリソースを予約するとともに、無線中継局２へ経路変更指示メッセージＳ１３を送信する。不可能な場合は、無線中継局１に対して経路変更不可メッセージを返信する。ここでは、可能な場合について説明する。 In the radio relay station 7 that has received the route change request message S12, the resource management unit 25 confirms the resources that can be allocated and the link state between the radio relay station 2 and the radio relay station 6 from the route determination unit 24, and then relays. Determine whether or not. If possible, the resource management unit 25 reserves resources between the links and transmits a route change instruction message S13 to the radio relay station 2. If impossible, a route change impossible message is returned to the radio relay station 1. Here, a possible case will be described.

経路変更指示メッセージＳ１３を受信した無線中継局２は、経路決定部２４が、無線中継局１を経由させていたパケット送信の経路を無線中継局７経由の経路に変更し、無線中継局７に対して経路変更完了メッセージＳ１４を返信する。 In the wireless relay station 2 that has received the route change instruction message S13, the route determination unit 24 changes the route of packet transmission that has been routed through the wireless relay station 1 to the route that passes through the wireless relay station 7, and the wireless relay station 7 In response, a route change completion message S14 is returned.

経路変更完了メッセージＳ１４を受信した無線中継局７は、経路決定部２４が、無線中継局１に対して経路変更完了メッセージＳ１５を返信する。 In the wireless relay station 7 that has received the route change completion message S14, the route determination unit 24 returns a route change completion message S15 to the wireless relay station 1.

無線中継局１は、経路変更完了メッセージＳ１５を受信した場合、リソース管理部２５で無線移動局１１へリソースを割り当てた後、経路決定部２４が無線移動局１１に対して接続完了メッセージＳ１６を返信する。なお、無線中継局１は、経路変更不可メッセージを受信した場合、経路決定部２４が、他の中継パケットを含めて自局以外の中継候補となる無線中継局に対して経路変更要求メッセージＳ１２を送信する。以降の処理については、無線中継局７に対して経路変更要求メッセージＳ１２を送信した場合と同様である。全ての中継候補となる無線中継局からの返答が不可（経路変更不可メッセージ）であった場合、無線中継局１では、経路決定部２４が無線移動局１１に対して接続拒否メッセージを返信する。 When the wireless relay station 1 receives the route change completion message S15, the resource management unit 25 allocates resources to the wireless mobile station 11, and then the route determination unit 24 returns a connection completion message S16 to the wireless mobile station 11. To do. When the wireless relay station 1 receives the route change impossible message, the route determination unit 24 sends a route change request message S12 to the wireless relay station that is a relay candidate other than the local station including other relay packets. Send. The subsequent processing is the same as when the route change request message S12 is transmitted to the radio relay station 7. When the response from the wireless relay stations that are all relay candidates is not possible (route change impossible message), in the wireless relay station 1, the route determination unit 24 returns a connection rejection message to the wireless mobile station 11.

以上説明したように、本実施の形態では、無線移動局から接続要求を受信した際に無線移動局へ割り当てる無線リソースが不足する場合、無線中継局は、自局に代わってパケット中継を行う候補の無線中継局に対して経路変更を要求し、候補の無線中継局では、経路の切り替えが可能な場合にパケット中継の経路を変更することとした。これにより、無線移動局から接続要求を受信した無線中継局では、無線移動局へ割り当てる無線リソースを確保することができる。 As described above, in this embodiment, when a radio resource to be allocated to a radio mobile station is insufficient when a connection request is received from the radio mobile station, the radio relay station is a candidate for performing packet relay on behalf of itself. The wireless relay station is requested to change the route, and the candidate wireless relay station changes the route of the packet relay when the route can be switched. As a result, the radio relay station that has received the connection request from the radio mobile station can secure radio resources to be allocated to the radio mobile station.

実施の形態３．
本実施の形態では、リソースを確保したい無線中継局が、パケット転送先の無線中継局に対して経路変更要求メッセージを送信する。実施の形態１と異なる部分について説明する。なお、初期状態は実施の形態１と同様とする。 Embodiment 3 FIG.
In the present embodiment, a radio relay station that wants to secure resources transmits a route change request message to a packet transfer destination radio relay station. A different part from Embodiment 1 is demonstrated. The initial state is the same as in the first embodiment.

図６は、無線中継局および無線移動局での経路切替処理を示すシーケンス図である。無線移動局１１から接続要求メッセージＳ２１を受信した場合、無線中継局１では、リソース管理部２５で確認した結果、無線移動局１１へ割り当てるリソースが不足している。そのため、無線中継局１は、リソースを確保するため、経路決定部２４が、中継パケットの転送先の無線中継局から１つの無線中継局（ここでは無線中継局６とする）を選択し、無線中継局６へ経路変更要求メッセージＳ２２を送信する。 FIG. 6 is a sequence diagram showing route switching processing in the radio relay station and the radio mobile station. When the connection request message S21 is received from the wireless mobile station 11, the wireless relay station 1 has confirmed that the resource management unit 25 has insufficient resources to be allocated to the wireless mobile station 11. Therefore, in the radio relay station 1, in order to secure resources, the route determination unit 24 selects one radio relay station (in this case, the radio relay station 6) from the radio relay stations to which the relay packet is transferred, and the radio relay station 1 A route change request message S22 is transmitted to the relay station 6.

経路変更要求メッセージＳ２２を受信した無線中継局６は、経路決定部２４が無線中継局１を経由しない他のルート（例えば、無線中継局２−無線中継局７−無線中継局６）を選択し、無線中継局７へ中継の可否を問い合わせる経路変更確認メッセージＳ２３を送信する。 The wireless relay station 6 that has received the route change request message S22 selects another route (for example, wireless relay station 2−wireless relay station 7−wireless relay station 6) that the route determination unit 24 does not pass through the wireless relay station 1. Then, a route change confirmation message S23 for inquiring whether the relay is possible or not is transmitted to the radio relay station 7.

経路変更確認メッセージＳ２３を受信した無線中継局７では、リソース管理部２５が、割り当て可能なリソースおよび経路決定部２４からの無線中継局２とのリンク状態を確認してから中継の可否を判定する。可能な場合は、リソース管理部２５で各リンク間のリソースを予約するとともに、無線中継局２へ経路変更指示メッセージＳ２４を送信する。不可能な場合は、無線中継局６に対して経路変更不可能を応答とする経路変更応答メッセージＳ２６を返信する。ここでは、可能な場合について説明する。 In the wireless relay station 7 that has received the route change confirmation message S23, the resource management unit 25 determines whether or not relaying is possible after confirming the resources that can be allocated and the link state with the wireless relay station 2 from the route determination unit 24. . If possible, the resource management unit 25 reserves resources between the links and transmits a route change instruction message S24 to the radio relay station 2. If not possible, a route change response message S26 is returned to the wireless relay station 6 as a response indicating that the route cannot be changed. Here, a possible case will be described.

経路変更指示メッセージＳ２４を受信した無線中継局２は、経路決定部２４が、無線中継局１を経由させていたパケット送信の経路を無線中継局７経由の経路に変更し、無線中継局７に対して経路変更完了メッセージＳ２５を返信する。 In the wireless relay station 2 that has received the route change instruction message S24, the route determination unit 24 changes the route of packet transmission that has been routed through the wireless relay station 1 to the route that is routed through the wireless relay station 7, and the wireless relay station 7 In response, a route change completion message S25 is returned.

経路変更完了メッセージＳ２５を受信した無線中継局７は、経路決定部２４が、無線中継局６に対して経路変更可能を応答とする経路変更応答メッセージＳ２６を返信する。 Upon receiving the route change completion message S25, the wireless relay station 7 returns a route change response message S26 in which the route determination unit 24 returns a response indicating that the route change is possible to the wireless relay station 6.

無線中継局６は、経路変更可能を応答とする経路変更応答メッセージＳ２６を受信した場合、経路決定部２４が、無線中継局１に対して経路変更完了メッセージＳ２７を返信する。なお、無線中継局６は、経路変更不可能を応答とする経路変更応答メッセージＳ２６を受信した場合、経路決定部２４が、他の経路の無線中継局について同様の中継可否の確認を行う。全ての経路の無線中継局からの経路変更応答メッセージＳ２６が経路変更不可能の応答の場合、経路決定部２４が無線中継局１に対して経路変更不可メッセージを返信する。 When the wireless relay station 6 receives the route change response message S <b> 26 whose response is that the route can be changed, the route determination unit 24 returns a route change completion message S <b> 27 to the wireless relay station 1. When the wireless relay station 6 receives the route change response message S26 that indicates that the route cannot be changed, the route determination unit 24 confirms whether or not relaying is possible for the wireless relay stations on other routes. When the route change response message S26 from the wireless relay stations of all routes is a response that the route cannot be changed, the route determination unit 24 returns a route change impossible message to the wireless relay station 1.

無線中継局１は、経路変更完了メッセージＳ２７を受信した場合、リソース管理部２５で無線移動局１１へリソースを割り当てた後、経路決定部２４が無線移動局１１に対して接続完了メッセージＳ２８を送信する。なお、無線中継局１は、経路変更不可メッセージを受信した場合、経路決定部２４が、他の中継パケットの転送先である無線中継局５に対して経路変更要求メッセージＳ２２を送信する。以降の処理については、無線中継局６に対して経路変更要求メッセージＳ２２を送信した場合と同様である。全ての中継パケットの転送先の無線中継局からの返信が不可（経路変更不可メッセージ）であった場合、無線中継局１では、経路決定部２４が無線移動局１１に対して接続拒否メッセージを送信する。 When the wireless relay station 1 receives the route change completion message S27, the resource management unit 25 allocates resources to the wireless mobile station 11, and then the route determination unit 24 transmits a connection completion message S28 to the wireless mobile station 11. To do. When the wireless relay station 1 receives the route change impossible message, the route determination unit 24 transmits a route change request message S22 to the wireless relay station 5 that is a transfer destination of another relay packet. The subsequent processing is the same as when the route change request message S22 is transmitted to the radio relay station 6. In the case where it is impossible to reply from all the relay packet transfer destination wireless relay stations (route change impossible message), in the wireless relay station 1, the route determination unit 24 transmits a connection rejection message to the wireless mobile station 11. To do.

以上説明したように、本実施の形態では、無線移動局から接続要求を受信した際に無線移動局へ割り当てるリソースが不足する場合、無線中継局は、パケット中継している当該パケットの転送先の無線中継局に対して経路変更を要求し、転送先の無線中継局では、無線移動局から接続要求を受信した無線中継局に代わってパケット中継を行う候補の無線中継局に対して経路変更を要求し、候補の無線中継局では、経路の切り替えが可能な場合にパケット中継の経路を変更することとした。これにより、無線移動局から接続要求を受信した無線中継局では、無線移動局へ割り当てる無線リソースを確保することができる。 As described above, in this embodiment, when a resource to be allocated to a radio mobile station is insufficient when a connection request is received from the radio mobile station, the radio relay station sets the transfer destination of the packet being relayed by the packet. Request a route change to the wireless relay station, and the transfer destination wireless relay station changes the route to the candidate wireless relay station that performs packet relay on behalf of the wireless relay station that has received the connection request from the wireless mobile station. The candidate radio relay station requests that the packet relay route be changed when the route can be switched. As a result, the radio relay station that has received the connection request from the radio mobile station can secure radio resources to be allocated to the radio mobile station.

以上のように、本発明にかかる経路切替方法は、パケット中継を行う通信に有用であり、特に、マルチホップセルラネットワーク通信に適している。 As described above, the route switching method according to the present invention is useful for communication that performs packet relay, and is particularly suitable for multi-hop cellular network communication.

１、２、３、４、５、６、７無線中継局
１１、１２、１３無線移動局
２１無線Ｉ／Ｆ部
２２無線信号中継部
２３制御メッセージ処理部
２４経路決定部
２５リソース管理部
３１無線Ｉ／Ｆ部
３２制御メッセージ処理部 1, 2, 3, 4, 5, 6, 7 Radio relay station 11, 12, 13 Radio mobile station 21 Radio I / F unit 22 Radio signal relay unit 23 Control message processing unit 24 Route determination unit 25 Resource management unit 31 Radio I / F unit 32 Control message processing unit

Claims

A method for switching a packet relay route in a multi-hop cellular network,
A specific relay station, which is a relay station that has received a connection request from a mobile station, checks whether there are resources that can be allocated to the mobile station. A route change request step for sending a route change request to have the packet relayed by a different relay station;
Based on the route change request, a device other than the specific relay station performs a process of switching the relay route of the packet to a route that does not include the specific relay station, and then the specific device of the route change request transmission source. A route change switching step for sending a route change completion notification to the relay station;
The specific relay station that has received the route change completion notification allocates resources to the mobile station that is the connection request transmission source,
A path switching method comprising:

A device other than the specific relay station, a packet transmission source device that is the transmission source of the packet, and a candidate for a relay station that relays the packet on behalf of the specific relay station,
In the route change switching step,
The packet transmission source device that has received the route change request confirms whether packet relay is possible to the candidate relay station,
The candidate relay station determines whether or not packet relay is possible, and transmits the determination result to the packet transmission source device.
When the packet transmission source apparatus determines that there is a relay station capable of packet relay among the candidate relay stations based on the determination result, the packet transmission destination is changed from the specific relay station to the packet relay. Process to switch to a relay station capable of transmitting a route change request to the specific relay station of the route change request transmission source,
The route switching method according to claim 1, wherein:

A device other than the specific relay station, a candidate for a relay station that relays the packet on behalf of the specific relay station, and a packet transmission source device that is a transmission source of the packet,
In the route change switching step,
When the candidate relay station that has received the route change request determines whether or not packet relay is possible on a route that does not include the specific relay station, and determines that the packet relay is possible on the local station, Sending a switching instruction to the packet transmission source device to switch the packet transmission destination from the specific relay station to the own station,
The packet transmission source device that has received the switching instruction performs a process of switching the packet transmission destination from the specific relay station to the switching instruction transmission source relay station, via the switching instruction transmission source relay station A route change completion notification is sent to the specific relay station of the route change request transmission source,
The route switching method according to claim 1, wherein:

A device other than the specific relay station is a packet transfer destination device that is a transfer destination of the packet, a candidate for a relay station that relays the packet on behalf of the specific relay station, and a source of the packet A packet source device,
In the route change switching step,
The packet transfer destination device that has received the route change request confirms whether the packet can be relayed to the candidate relay station,
When the candidate relay station determines whether or not packet relay is possible, and determines that the packet relay is possible at the local station, the packet transmission destination is specified with respect to the packet transmission source device. Send a switching instruction to switch from the relay station to your station,
The packet transmission source device that has received the switching instruction performs processing for switching the packet transmission destination from the specific relay station to the switching instruction transmission source relay station, and the switching instruction transmission source relay station and the packet transfer A route change completion notification is transmitted to the specific relay station that is the route change request transmission source via the destination device.
The route switching method according to claim 1, wherein:

The specific relay station transmits a route change request specifying a packet amount according to a required resource;
The route switching method according to any one of claims 1 to 4, wherein:

A relay station that forms a multi-hop cellular network together with a mobile station,
Resource management means for managing resources;
Route determining means for determining a relay route of the packet;
With
When a connection request is received from a mobile station, the resource management means checks whether there is a resource that can be allocated to the mobile station,
As a result of the confirmation, when the resource is insufficient, the route determination means transmits a route change request for relaying a packet relayed by the own station by a different relay station,
In response to the route change request, when a route change completion notification indicating that the route has been changed to a relay route not including its own station is received, the resource management unit allocates resources to the mobile station that is the connection request transmission source. ,
A relay station characterized by that.

When a route change request is received as a packet source device that is a packet source,
The route determining means includes
A relay station that checks whether or not packet relay is possible for a relay station candidate that relays the packet on behalf of the relay station that is the source of the route change request, and can relay the packet among the candidate relay stations When it is determined that there is a process, the packet transmission destination is switched to a relay station capable of relaying the packet, and then a route change completion notification is transmitted to the relay station that is the route change request transmission source.
The relay station according to claim 6.

When acting as a candidate for a relay station that relays packets on behalf of the relay station of the route change request source,
The resource management means includes
Determining whether packet relay is possible on a route not including the relay station of the route change request transmission source, and transmitting the determination result to the packet transmission source device;
The relay station according to claim 7.

When a route change request is received as a candidate for a relay station that relays packets on behalf of the relay station that is the source of the route change request,
The resource management means includes
When it is determined whether packet relay is possible on a route that does not include the relay station that is the source of the route change request, and when it is determined that packet relay is possible at the local station, the packet source device that is the source of the packet is On the other hand, a switching instruction is transmitted to switch the transmission destination of the packet to the own station.
The relay station according to claim 6.

When a switching instruction is received as a packet transmission source device that is a packet transmission source,
The route determining means includes
Performing a process of switching the transmission destination of the packet to the switching instruction transmission source relay station, and transmitting the route change completion notification via the switching instruction transmission source relay station,
The relay station according to claim 9.

When a switching instruction is received as a packet transfer destination device that is a packet transfer destination,
The route determining means includes
Check whether the packet relay is possible for the candidate relay station that relays the packet on behalf of the relay station that is the source of the route change request.
The relay station according to claim 6.

When acting as a candidate for a relay station that relays packets on behalf of the relay station that is the source of the route change request,
The resource management means includes
The packet transmission source device that is the transmission source of the packet when it is determined whether or not the packet relay is possible on the route that does not include the relay station that is the transmission source of the route change request, and the packet relay is possible at the local station Send a switching instruction to switch the packet transmission destination to its own station,
The relay station according to claim 11.

When a switching instruction is received as a packet transmission source device that is a packet transmission source,
The route determining means includes
Performs processing to switch the packet transmission destination to the switching instruction transmission source relay station, and transmits a route change completion notification via the switching instruction transmission source relay station and the packet transfer destination device,
The relay station according to claim 12.

The route determination means transmits a route change request specifying a packet amount according to a required resource;
The relay station according to any one of claims 6 to 13.