JP2004289411A - Control method and controller for radio network - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a user to be closer to the position when the user is interested in the information on a service provider. <P>SOLUTION: Received signal power values for every azimuthal angle to each adjacent radio station in the service area of one radio station are transmitted/received between each radio station. Adjacent radio station table of the azimuthal angles and the received signal power values of each adjacent radio station from one's own station and a topology table of the azimuthal angles and the received signal power values of each adjacent radio station, which is the radio station in the service area of each adjacent radio station, are generated and stored. The number of hops to a destination radio station up to the adjacent radio station and the destination radio station is calculated. And, it is stored as a routing table. The distance from one's own station to each radio station in the radio network, the azimuthal angle, and the number of the hops are calculated. And they are stored as a positional information estimating table. The distance to each radio station, the azimuthal angle, and the number of the hops included in the positional information estimating table, are displayed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００７２】
図２７の例では、自無線局１−Ｎの隣接無線局は１−Ｍであり無線局１−Ｌは直接通信できない無線局（隣々接無線局）の配置となっているが、トポロジ情報から角度（１−Ｌ）−（１−Ｍ）−（１−Ｎ）が１２０度であることが分かる。また、距離Ｌａ，Ｌｂが上記数１で計算できるので、残りの距離Ｌｃを上記数２にて計算することができる。また、同様にして角度（１−Ｎ）−（１−Ｌ）−（１−Ｍ）や角度（１−Ｌ）−（１−Ｎ）−（１−Ｍ）も算出することが可能となっている。このように隣々接無線局の方位角と距離を計算した後、その先の無線局を計算することで、自無線局からの全ての無線局への方位角を算出することが可能となる。
【００７３】
さらに、本実施形態で用いるサービス提供方式について以下に説明する。実際にサービス（動画や、静止画、音声又はテキストデータなど）を提供するとき、サービス提供者の無線局からのホップ数によってサービス品質を変化させる（例えば図２８参照。）。例えば、以下のようにサービス内容を変化させる。
（Ａ）サービス提供者の無線局から１ホップ圏内→高品質のサービス提供（例えば、動画を含むすべてのサービスの提供）。
（Ｂ）サービス提供者の無線局から２〜３ホップ圏内→中品質サービス提供（例えば、静止画や音声のみのサービスの提供）。
（Ｃ）サービス提供者の無線局から４ホップ以上→低品質のサービス提供（例えば、音声又はテキストデータのみのサービスの提供）。
【００７４】
以上のように構成することにより、情報を受信する側でサービス品質を変更することが可能となり、興味がある内容ならば近づくことにより、より一層品質の良いサービスを受けることが可能となる。また、興味の無い情報でも遠ざかることにより、無駄な情報を受信し転送する必要が少なくなる。なお、上記のホップ数の例は一例であり、図２８の例では、以下のように実行されている。
（Ａ）サービス提供者の無線局１−Ｈから１ホップ圏内でのサービスエリアＳ_Ｈにおいて、高品質のサービスが当該サービスエリアＳ_Ｈ内の各無線局１−ｈに対して提供されている。
（Ｂ）サービス提供者の無線局１−Ｈから２ホップ圏内でのサービスエリアＳ_Ｍ１，Ｓ_Ｍ２において、中品質のサービスが当該サービスエリアＳ_Ｍ１，Ｓ_Ｍ２内の各無線局１−ｍに対して提供されている。
（Ｃ）サービス提供者の無線局１−Ｈから３ホップ圏内でのサービスエリアＳ_Ｌ１，Ｓ_Ｌ２，Ｓ_Ｌ３において、低品質のサービスが当該サービスエリアＳ_Ｌ１，Ｓ_Ｌ２，Ｓ_Ｌ３内の各無線局１−ｌに対して提供されている。
【００７５】
図２９は図２の上位レイヤ処理装置１０７によってネットワーク層において用いられ上位レイヤ処理装置１０７に接続されたテーブルメモリ１０７ａに格納される隣接無線局テーブルの一例を示す図である。当該隣接無線局テーブルは、図２９に示すように、各隣接無線局の名称毎に、方位角と受信信号電力値の情報が格納されている。
【００７６】
図３０は図２の上位レイヤ処理装置１０７によってネットワーク層において用いられ上位レイヤ処理装置１０７に接続されたテーブルメモリ１０７ａに格納されるトポロジテーブルの一例を示す図である。当該トポロジテーブルは、図３０に示すように、各隣接無線局の名称毎に、各隣々接無線局に対する方位角及び受信信号電力値の情報が格納されている。
【００７７】
図３１は図２の上位レイヤ処理装置１０７によってネットワーク層において用いられ上位レイヤ処理装置１０７に接続されたテーブルメモリ１０７ａに格納されるルーティングテーブルの一例を示す図である。当該ルーティングテーブルは、図３１に示すように、自無線局から宛先無線局にルーティングするときに、宛先無線局毎に、隣接無線局と、宛先無線局までのホップ数が格納されている。
【００７８】
図３２は図２の上位レイヤ処理装置１０７によってネットワーク層において用いられ上位レイヤ処理装置１０７に接続されたテーブルメモリ１０７ａに格納される位置情報推定テーブルの一例を示す図である。当該位置情報推定テーブルは、図３２に示すように、当該無線アドホックネットワークにおいて認識している各無線局毎に、自無線局からの距離、方位角、ホップ数が格納されている。
【００７９】
図３３は図２の上位レイヤ処理装置１０７によってＭＡＣ層において実行される方位角付きトポロジ情報配布処理を示すフローチャートである。図３３において、ＮＯＳＹＮＣ、ＡＳＹＮＣ、ＳＹＮＣは以下の状態をいう。
（Ａ）ＮＯＳＹＮＣ：初期状態であって、自局のトポロジテーブルにおいて無線局の情報が全く無く、隣接無線局からのハローパケットから得られる隣接無線局のトポロジ情報においても自無線局の情報が無い場合をいう。
（Ｂ）ＡＳＹＮＣ：自局のトポロジテーブルにおいて他の無線局の情報があるが、隣接無線局からのハローパケットから得られる隣接無線局のトポロジ情報においても自無線局の情報が無い場合をいう。
（Ｃ）ＳＹＮＣ：自局のトポロジテーブルにおいて他の無線局の情報があるが、隣接無線局からのハローパケットから得られる隣接無線局のトポロジ情報においても自無線局の情報が有る場合をいう。
【００８０】
なお、ハローパケットは、各無線局１において所定の周期で周期的に送信するイベントを発生させ、キャリアセンスにより受信搬送波を受信しないときにハローパケットを送信する。
【００８１】
図３３のステップＳ１０１において、まず、ハローパケットを送信するイベントが発生したか否かが判断され、ＹＥＳのときはステップＳ１０４に進む一方、ＮＯのときはステップＳ１０２に進む。ステップＳ１０２において、ハローパケットを受信するイベントが発生したか否かが判断され、ＹＥＳのときはステップＳ１０３に進み、図３４の受信処理を実行した後、ステップＳ１０１に戻る。ステップＳ１０２でＮＯのときはステップＳ１０１に戻る。次いで、ステップＳ１０４において、方位角対受信信号電力値テーブルに基づいて隣接無線局の方位角及び受信信号電力情報を取得してステップＳ１０５に進む。ステップＳ１０５では、ＮＯＳＹＮＣであるか否かが判断され、ＹＥＳのときはステップＳ１０９に進む一方、ＮＯのときはステップＳ１０６に進む。ステップＳ１０６では、取得した情報を隣接無線局テーブルに登録し、ステップＳ１０７においてＡＳＹＮＣである否かを判断し、ＹＥＳのときはステップＳ１０９に進む一方、ＮＯのときはＳＹＮＣであると判断してステップＳ１０８に進む。ステップＳ１０８では、取得した情報をトポロジテーブルに登録した後、ステップＳ１０９に進む。さらに、ステップＳ１０９では、トポロジテーブルに基づいてハローパケットを生成し、ステップＳ１１０で生成したハローパケットをブロードキャストで送信し、ステップＳ１０１に戻る。
【００８２】
図３４は図３３のサブルーチンである受信処理（ステップＳ１０３）を示すフローチャートである。
【００８３】
図３４のステップＳ１１１において、受信したハローパケットの送信元ＩＰアドレスを隣接無線局テーブルに登録し、ステップＳ１１２でＳＹＮＣであるか否かを判断し、ＹＥＳのときはステップＳ１１４に進む一方、ＮＯのときはステップＳ１１３に進む。ステップＳ１１３では、受信した情報をトポロジテーブルに登録した後、ステップＳ１１４で、ディシクストラ法に基づき最短ホップルートを抽出する。次いで、ステップＳ１１５において抽出したルートをルーティングテーブルに登録し、ステップＳ１１６において図３５のルートからの位置情報推定処理を実行し、元のメインルーチンに戻る。
【００８４】
なお、ステップＳ１１４でのディシクストラ法に基づく最短ホップルートの抽出処理は以下のように実行される。
＜ステップＳＳ１＞トポロジテーブルから任意の宛先無線局を選択する。
＜ステップＳＳ２＞トポロジテーブルから自無線局を含むリンク情報を全て抽出する。
＜ステップＳＳ３＞抽出したリンク情報を「一時的なルート」として保持し、ここで、１ホップでもルートと扱う。
＜ステップＳＳ４＞各「一時的なルート」に任意の宛先無線局があるかどうかチェックする。ここで、宛先無線局があればステップＳＳ６に進む一方、宛先無線局がなければ、トポロジテーブルから各「一時的なルート」の終点無線局を含むリンク情報を全て抽出する。
＜ステップＳＳ５＞抽出したリンク情報を各「一時的なルート」に追加して新たな「一時的なルート」として保持してステップＳＳ４に進む。また、「一時的なルート」の終点無線局を含むリンク情報が１つも無ければ到達不可能としてステップＳＳ６に進む。
＜ステップＳＳ６＞トポロジテーブルから任意の宛先無線局を全て選択したかチェックを行う。行っていなければステップＳＳ１に進む一方、行っていれば処理終了となる。
【００８５】
図３５及び図３６は図３４のサブルーチンであるルートからの位置情報推定処理（ステップＳ１１５）のフローチャートである。なお、この位置情報推定処理を実行するときに、図２９乃至図３１のテーブルを参照する。
【００８６】
図３５のステップＳ１２１において隣接無線局テーブルから未選択の１つの隣接無線局を選択し、ステップＳ１２２においてトポロジテーブルから選択された１つの隣接無線局から隣接する隣々接無線局の情報を取得する。次いで、ステップＳ１２３において上記取得した情報に基づいて、選択した隣接無線局における自無線局と隣々接無線局の間の角度を算出し、ステップＳ１２４において上記数１を用いて自無線局と隣々接無線局との距離を算出する。さらに、ステップＳ１２５において上述のごとく余弦定理を用いて自無線局と隣々接無線局との方位角を算出し、ステップＳ１２６において算出された情報を位置情報推定テーブルに登録する。ステップＳ１２７においてすべての隣接無線局について処理したか否かが判断され、ＹＥＳのときは図３６のステップＳ１３１に進む一方、ＮＯのときはステップＳ１２１に戻る。
【００８７】
図３６のステップＳ１３１において、ホップ数パラメータｎに２を設定し、ステップＳ１３２においてトポロジテーブルからｎホップ先の未選択の１つの無線局を選択し、ステップＳ１３３において選択した無線局の情報をトポロジテーブルから取得する。次いで、ステップＳ１３４において隣々接無線局における自無線局と選択したｎホップ先の無線局の角度を算出し、ステップＳ１３５において自無線局と選択したｎホップ先の無線局との距離を算出する。さらに、ステップＳ１３６において自無線局からの、選択したｎホップ先の無線局の方位角を算出する。そして、ステップＳ１３７において算出された情報を位置情報推定テーブルに登録してステップＳ１３８に進む。ステップＳ１３８においてｎホップ先のすべての無線局について処理したか否かが判断され、ＹＥＳのときはステップＳ１３９に進む一方、ＮＯのときはステップＳ１３２に戻り、上記の処理を繰り返す。ステップＳ１３９においてｎ＞Ｎｍａｘ（Ｎｍａｘは、当該無線アドホックネットワークにおける最大ホップ数である。）であるか否かが判断され、ＹＥＳのときは元のメインルーチンに戻るが、ＮＯのときはステップＳ１４０においてホップ数パラメータｎを１だけインクリメントした後、ステップＳ１３２に戻る。
【００８８】
次いで、図３７乃至図４０を参照して、ネットワーク層での処理の一例について以下に説明する。図３７のトポロジ情報配布処理では、周辺の無線局に対して方位角情報と距離情報を配布し、すなわち、定期的にトポロジ情報を配布する。次いで、図３８のトポロジ情報配布処理では、周辺無線局（ここで、周辺無線局とは、自局以外の無線局をいう。）への方位角情報と距離情報を配布が実行されるが、それらの情報の受信時に隣接無線局以外を抽出し、抽出した無線局への方位角を計算した後、トポロジテーブルへ追加登録する。また、図３９の隣接無線局以外の距離及び方位角計算処理においては、余弦定理を使って次式のごとく距離Ｌｃを計算する。
【００８９】
【数３】
Ｌｃ^２
＝Ｌａ^２＋Ｌｂ^２−２・Ｌａ・Ｌｂ・ｃｏｓθ
＝１６９＋２２５−２×１３×１５×（−０．５）
【数４】
Ｌｃ＝２４．２６９３２２１９９０２３１９３９８１０６３１７６３３３８１１
【数５】
Ｌｃ≒２４．３
【００９０】
さらに、図４０の距離計算処理では、次式のごとく、余弦定理を使って方位角θを計算する。
【００９１】
【数６】
Ｌｃ^２＝Ｌａ^２＋Ｌｂ^２−２・Ｌａ・Ｌｂ・ｃｏｓθ
２２５＝５８９＋１６９−２×１３×２４．３×ｃｏｓθ
【数７】
ｃｏｓθ
＝０．８４３６２１３９９１７６９５４７３２５１０２８８０６５８４３６２
【数８】
θ≒３２度
【００９２】
さらに、本実施形態に係る、ホップ数に応じてサービス品質を変更するアプリケーション層の処理について以下に詳細に説明する。
【００９３】
図４１には、この処理に用いるサービスパケットであって、図２の上位レイヤ処理装置１０７においてアプリケーション層で用いられるサービスパケットのフォーマットを示している。図４１のサービスパケットにおいて、サービス識別のシリアル番号を付与するサービスＩＤ及び送信元アドレス（無線局アドレス）に続いて、サービス毎に、サービス配布範囲及びサービスデータが格納されている。ここで、ＳＮ１、ＳＮ２は各サービスのシリアル番号を示す。また、上記サービス配布範囲には最大ホップ数が格納され、対応するサービスデータをどの範囲まで配布するかをこの情報で示す。例えば、デフォルトでは、動画などの高品質のサービスについては最大ホップ数は１であり、静止画などの中品質のサービスについては最大ホップ数は３であり、音声やテキストデータなどの低品質のサービスについては最大ホップ数は４以上である。さらに、サービスデータＳＮ１は例えば動画であり、サービスデータＳＮ２は静止画であり、サービスデータＳＮ３は音声やテキストデータである。これにより、各サービス配布範囲における配信されるデータの品質を変更することができる。
【００９４】
図４２は、図２の上位レイヤ処理装置１０７によってアプリケーション層において実行されるサービス処理を示すフローチャートである。
【００９５】
図４２のステップＳ１４１において、まず、サービス発信イベントが発生したか否かが判断され、ＹＥＳのときはステップＳ１４４に進み、図４３のサービス発信処理を実行した後ステップＳ１４１に戻る一方、ステップＳ１４１でＮＯのときはステップＳ１４２に進む。次いで、ステップＳ１４２においてサービス受信イベントが発生したか否かが判断され、ＹＥＳのときはステップＳ１４５に進み、図４４のサービス受信処理を実行した後ステップＳ１４１に戻る一方、ステップＳ１４２でＮＯのときはステップＳ１４３に進む。さらに、ステップＳ１４３においてサービス転送イベントが発生したか否かが判断され、ＹＥＳのときはステップＳ１４６に進み、図４５のサービス転送処理を実行した後ステップＳ１４１に戻る一方、ステップＳ１４３でＮＯのときはステップＳ１４１に戻る。
【００９６】
図４３は図４２のサブルーチンであるサービス発信処理（ステップＳ１４４）を示すフローチャートである。
【００９７】
図４３のステップＳ１５１において、まず、サービスＩＤを取得し、サービスパケットに格納し、ステップＳ１５２において自無線局のＩＰアドレスを取得し、サービスパケットに格納する。次いで、ステップＳ１５３において位置情報推定テーブルに１ホップ先に無線局が１台以上存在するか否かが判断され、ＹＥＳのときはステップＳ１５４に進む一方、ＮＯのときはステップＳ１５９に進む。ステップＳ１５４において高品質のサービスデータ及び高品質のサービス配布範囲を取得し、サービスパケットに格納し、ステップＳ１５５において位置情報推定テーブルに２ホップと３ホップ先に無線局が１台以上存在するか否かが判断され、ＹＥＳのときはステップＳ１５６に進む一方、ＮＯのときはステップＳ１５９に進む。さらに、ステップＳ１５６において中品質のサービスデータ及び中品質のサービス配布範囲を取得し、サービスパケットに格納し、ステップＳ１５７において位置情報推定テーブルに４ホップ先に無線局が１台以上存在するか否かが判断され、ＹＥＳのときはステップＳ１５８に進む一方、ＮＯのときはステップＳ１５９に進む。そして、ステップＳ１５８において低品質のサービスデータおよび低品質のサービス配布範囲を取得し、サービスパケットに格納し、ステップＳ１５９においてサービスパケットをブロードキャストアドレスに送信し、ステップＳ１６０においてサービスＩＤをインクリメントした後、元のメインルーチンに戻る。
【００９８】
図４４は図４２のサブルーチンであるサービス受信処理（ステップＳ１４５）を示すフローチャートである。
【００９９】
図４４のステップＳ１６１においてサービスＩＤと宛先アドレスを取得し、重複していないか否かが判断され、ＹＥＳのときはステップＳ１６２に進む一方、ＮＯのときは元のメインルーチンに戻る。次いで、ステップＳ１６２において受信したサービスパケット内のサービスデータを保存し、ステップＳ１６３においてサービス転送イベントに登録した後、元のメインルーチンに戻る。なお、図４４のステップＳ１６１では、受信したサービスパケットが別の無線局から再度送られてくる場合、同等および品質の低いサービスの可能性があるため、処理せず破棄するために実行される。また、ステップＳ１６２では、受信したサービスデータを再生するために保存し、このとき、一番小さいサービス配布範囲を持つサービスデータを保存する。さらに、ステップＳ１６３では、サービス転送イベントを発生させて図４５のサービス転送処理を行う。
【０１００】
図４５は図４２のサブルーチンであるサービス転送処理（ステップＳ１４６）を示すフローチャートである。
【０１０１】
図４５のステップＳ１７１において位置情報推定テーブルからサービスパケットの送信元アドレスのホップ数Ｉを取得し、ステップＳ１７２においてサービスパケットからサービス配布範囲Ｊを取得する。次いで、ステップＳ１７３においてＪ＜Ｉ＋１であるか否かが判断され、ＹＥＳのときはステップＳ１７４に進む一方、ＮＯのときはステップＳ１７５に進む。ステップＳ１７４においてサービスパケットから一番高いサービスデータをサービス配布範囲を削除し、ステップＳ１７５においてサービスパケットをブロードキャストアドレスで送信した後、元のメインルーチンに戻る。
【０１０２】
図４５のステップＳ１７３の分岐処理においては、位置情報推定テーブルからサービスパケットの送信元のホップ数を取得することにより、現在サービスパケットが何ホップしているかを判断することができ、その情報を受信したサービスパケットのサービス配布範囲と比較することにより、サービスパケットのサービス配布範囲を超えていないかどうか調べることができる。そして、ステップＳ１７４の処理では、サービス発信者が決めた各サービス範囲を超える場合、その前のデータはパケットを大きくするだけで意味がないため、サービス配布範囲に必要なパケットのみ転送する処理を行うために実行している。
【０１０３】
以上の図４２乃至図４５のサービス処理においては、位置情報推定テーブルに基づいて、自局から宛先無線局までのホップ数に応じて伝送可能なサービスの品質を変化させることができる。
【０１０４】
図４６は図２の上位レイヤ処理装置１０７に接続された液晶ディスプレイ１０７ｂで表示されるルーティングテーブル表示ツールの一例を示す正面図であって、図４６（ａ）は当該表示ツールの外観を示す正面図であり、図４６（ｂ）は当該表示ツールにおいてエリアを分割しないで表示したときの一例であり、図４６（ｃ）は当該表示ツールにおいてエリアを２分割して表示したときの一例であり、図４６（ｄ）は当該表示ツールにおいてエリアを３分割して表示したときの一例である。図４６の中央部の白丸は自無線局の位置を示す一方、周辺部の黒丸は他の無線局を示している。
【０１０５】
図２の上位レイヤ処理装置１０７は、上述のごとく作成された図３１のルーティングテーブルの情報に基づいて、液晶ディスプレイ１０７ｂにおいて、例えば図４６に示すように、中心に表示する自無線局からの周辺無線局の概略距離（ホップ数に対応する）を表示し、上述のごとく、自無線局のユーザがサービスを所望するサービス提供者に近づくために、そのサービス提供者の無線局がどれぐらいのホップ数の位置にいるかを指示している。すなわち、図４６の表示ツールでは、同一ホップ数先にある無線局は、概略同一の半径の位置にいるがごとく、同心円の表示形式で表示している。
【０１０６】
図４６の表示ツールにおいて、表示エリアを分割しないときは図４６（ｂ）のごとく表示され、表示エリアを２分割したとき図４６（ｃ）のごとく表示され、表示エリアを３分割したときは図４６（ｄ）のごとく表示される。例えば、隣接無線局が３台あるとき、１ホップエリアを３等分（＝１２０度ごと）に分割してノードを配置し、それ以降のホップのノードについては、その隣接（次ホップ）ノードの方位角内に均等に配置することにより、当該表示を見易くしている。なお、周辺の無線局の表示部をマウスでクリック又はペンで指示したときは、図４６（ｄ）に示すように、当該周辺無線局のＩＰアドレス又はホスト名がポップアップして表示されるようになっている。また、図４６（ｂ）乃至（ｄ）における周辺無線局の丸印内の数字はＩＰアドレスの最後の３桁の数字を示している。
【０１０７】
図４７は図２の上位レイヤ処理装置１０７に接続された液晶ディスプレイ１０７ｂで表示されるトポロジ表示ツールの一例を示す正面図であって、（ａ）は当該表示ツールの外観を示す正面図であり、（ｂ）は当該表示ツールの広域表示での図であり、（ｃ）は当該表示ツールの標準表示での図であり、（ｄ）は当該表示ツールの詳細表示での図である。
【０１０８】
図２の上位レイヤ処理装置１０７は、上述のごとく作成された図３２の位置情報推定テーブルの情報に基づいて、液晶ディスプレイ１０７ｂにおいて、例えば図４７に示すように、自無線局を中心とした周辺無線局の位置（距離と方位角情報に基づく）を表示し、上述のごとく、自無線局のユーザがサービスを所望するサービス提供者に近づくために、そのサービス提供者の無線局がどれぐらいの距離のどの方位角の位置にいるかを指示している。これにより、自無線局のユーザがサービスを所望するサービス提供者に容易に近づくことができ、これにより、ホップ数が減少してより高い品質のサービスを受けることができる。
【０１０９】
なお、図４７の表示ツールにおいて、図４７（ｃ）における標準表示をしているときにより広域の周辺無線局の位置を確認したいときは、上位レイヤ処理装置１０７に接続される入力装置（図示せず。）の広域キーを押下することにより、図４７（ｂ）の広域表示となり、より多数の無線局の位置を見ることができる。また、図４７（ｃ）における標準表示をしているときにより近くの詳細な周辺無線局の位置を確認したいときは、上位レイヤ処理装置１０７に接続される入力装置（図示せず。）の詳細キーを押下することにより、図４７（ｄ）の詳細表示となり、周辺無線局の詳細な無線局の位置を見ることができる。また、図４６のルーティングテーブル表示ツールと同様に、周辺の無線局の表示部をマウスでクリック又はペンで指示したときは、図４７（ｃ）に示すように、当該周辺無線局のＩＰアドレス又はホスト名がポップアップして表示されるようになっている。また、図４７（ｃ）及び（ｄ）における周辺無線局の丸印内の数字はＩＰアドレスの最後の３桁の数字を示している。
【０１１０】
以上の実施形態においては、図４６のルーティングテーブル表示ツールにより周辺無線局のＩＰアドレス又はホスト名及びホップ数を表示し、図４７のトポロジ表示ツールにより周辺無線局の位置（自局からみた距離と方位角を表す）を示しているが、本発明はこれらの情報のうちの少なくとも１つを表示するようにしてもよい。
【０１１１】
以上の実施形態においては、可変ビームアンテナ１０１は、自局を中心とした水平面内の所定の方位角毎にセクタ形状のメインビームを選択的に変更可能なセクタビームパターンと、上記方位角毎にヌル点を形成可能な排他的セクタパターンとを選択的に切り換え可能に装備しているが、本発明はこれに限らず、セクタビームパターンは、自局を中心とした水平面内においてセクタ形状のメインビームの方位角を任意の方位角でディジタル的又はアナログ的に設定可能であってもよく、排他的セクタパターンは、ヌル点を形成する方位角を任意の方位角でデジタル的又はアナログ的に設定可能であってもよい。
【０１１２】
以上の実施形態においては、ＮＬＳテーブルは、ＡＳテーブルに基づいて作成されているので、ＡＳテーブルは常時保存する必要はなく、一時的な保存テーブルであってもよい。
【０１１３】
以上の実施形態においては、所定の方位角幅を有するセクタパターンを用いているが、セクタ形状でない所定の放射形状を有する放射パターンであってもよい。
【０１１４】
以上の実施形態においては、ルーティングを行うときの基準となる評価値として、信号対干渉雑音比（電力比又は信号比）を用いているが、本発明はこれに限らず、信号対雑音比（電力比又は信号比）（ここで、雑音はすべての雑音を含む。）、信号電力、信号強度などの信号強度を含む評価値を用いてもよい。
【０１１５】
以上の実施形態においては、各無線局間でパケット通信により無線通信を行っているが、本発明はこれに限らず、回線交換など他の交換方式により無線通信を行ってもよい。
【０１１６】
【実施例】
発明者らは、本実施形態に係るホタルネットのシステムを計算機シミュレーションにより実現し、これを使用して、ホタルネットの機能である角度付きトポロジ情報の評価を以下の通り行った。そのときのシミュレーション条件を次の表に示す。
【０１１７】
【表１】
―――――――――――――――――――――――――――――――――
（１）１０００ｍ×１０００ｍのエリアに３６台ノードが一様かつ
ランダムに配置されている。
（２）電波環境の変動要因は考慮しない。
（３）無線局の移動は無し。
（４）電波到達距離は３５０ｍ程度である。
―――――――――――――――――――――――――――――――――
【０１１８】
図４８は本実施形態に係るホタルネットの計算機シミュレーション結果であって、ホップ数に対する方位角の平均誤差及び距離の平均誤差を示すグラフである。図４８から明らかなように、ホップ数が増加しても方位角の誤差はほとんど変わらず５．６度程度に収まっている。また、３ホップ以降では誤差が減少しているが、今回使用したルーティングプロトコルにおいてホップ数が最小となるルートを選択するため、ホップ数が増加しても宛先無線局に対する角度と直前の中継無線局の角度がほとんど変わらず、距離の誤差があまり影響せず角度の誤差を減少させていると考えられる。また、距離に関してはややホップ数に従って増加しているが、近づく際の目安としては十分利用可能であると考えられる。
【０１１９】
【発明の効果】
以上詳述したように本発明に係る無線ネットワークの制御方法又は制御装置によれば、１つの無線局のサービスエリア内の各隣接無線局への所定の方位角毎の受信信号電力値の第１の情報テーブルを各無線局間で送受信し、上記受信した第１の情報テーブルに基づいて、自局から各隣接無線局の方位角及び受信信号電力値の第２の情報テーブルと、当該各隣接無線局のサービスエリア内の無線局である各隣々接無線局の方位角及び受信信号電力値の第３の情報テーブルとを生成して記憶装置に格納し、上記第２と第３の情報テーブルに基づいて、所定のルーティング基準により、宛先無線局に対する隣接無線局及び宛先無線局までのホップ数を計算して第４の情報テーブルとして記憶装置に格納し、上記第２と第３と第４の情報テーブルに基づいて、自局から上記無線ネットワーク内の各無線局への距離、方位角及びホップ数を計算して第５の情報テーブルとして記憶装置に格納し、上記第５の情報テーブルに含まれる各無線局への距離、方位角及びホップ数のうちの少なくとも１つを表示する。ここで、各無線局への距離及び方位角を表す位置を、自局を中心としたトポロジ表示形式で表示し、もしくは、各無線局へのホップ数を、自局を中心とした同心円の表示形式で表示する。従って、例えば情報を受信する側でサービス品質を変更することが可能となり、興味がある内容ならばユーザがサービス提供者の無線局に近づくことにより、より一層品質の良いサービスを受けることが可能となり、これにより、ユーザの要望を満たすことができる。
【０１２０】
さらに、上記無線ネットワークの制御方法において、上記第５の情報テーブルに基づいて、自局から宛先無線局までのホップ数に応じて伝送可能なサービスの品質を変化させる。従って、ホップ数に応じて伝送可能なサービスの品質を自動的に変化させることができるので、上述のようにユーザの要望を満たすことができるとともに、無線通信ネットワークにおいて柔軟な運用を行うことができ、これにより、データ伝送量に応じたトラフィックの制御をも行うことができる。さらには、ユーザが興味の無い情報の提供の無線局から遠ざかることにより、無駄なデータ伝送をすることを防止し、無線ネットワークを効率的に運用することができる。
【図面の簡単な説明】
【図１】本発明に係る一実施形態であるアドホック無線ネットワークを構成する複数の無線局１−１乃至１−９の平面配置図である。
【図２】図１の各無線局１の内部構成を示すブロック図である。
【図３】図１の可変ビームアンテナ１０１のセクタビームパターンの一例を示す図である。
【図４】図２のデータベースメモリ１５４に格納される方位角対ＳＩＮＲテーブル（ＡＳテーブル）の一例を示す図である。
【図５】図２のデータベースメモリ１５４に格納される隣接リンク状態テーブル（ＮＬＳテーブル）の一例を示す図である。
【図６】図２のデータベースメモリ１５４に格納される通信中テーブル（ＯＣテーブル）の一例を示す図である。
【図７】図１のアドホック無線ネットワークのＭＡＣ層で用いるＲＱ（Ｒｅｑｕｅｓｔ）信号のフレームフォーマットを示す図である。
【図８】図１のアドホック無線ネットワークのＭＡＣ層で用いるＲＥ（Ｒｅｐｌｙ）信号のフレームフォーマットを示す図である。
【図９】図１のアドホック無線ネットワークのＭＡＣ層で用いるＲＴＳ（Ｒｅｑｕｅｓｔ−ｔｏ−Ｓｅｎｄ）信号のフレームフォーマットを示す図である。
【図１０】図１のアドホック無線ネットワークのＭＡＣ層で用いるＣＴＳ（Ｃｌｅａｒ−ｔｏ−Ｓｅｎｄ）信号のフレームフォーマットを示す図である。
【図１１】図１のアドホック無線ネットワークのＭＡＣ層で用いるＤＡＴＡ信号のフレームフォーマットを示す図である。
【図１２】図１のアドホック無線ネットワークのＭＡＣ層で用いるＡＣＫ（Ａｃｋｎｏｗｌｅｄｇｅ）信号のフレームフォーマットを示す図である。
【図１３】図１のアドホック無線ネットワークにおいて既に他に通信が行われていることを知っている場合の各無線局の配置及びアンテナ放射パターンを示す平面図である。
【図１４】図１のアドホック無線ネットワークにおいて用いる各信号に対する各状態におけるアンテナ放射パターンを示す図である。
【図１５】図２のトラヒックモニタ部１０５内の管理制御部１５１によってＭＡＣ層で実行されるパケット送受信制御処理の第１の部分を示すフローチャートである。
【図１６】上記パケット送受信制御処理の第２の部分を示すフローチャートである。
【図１７】上記パケット送受信制御処理の第３の部分を示すフローチャートである。
【図１８】上記パケット送受信制御処理の第４の部分を示すフローチャートである。
【図１９】上記パケット送受信制御処理の第５の部分を示すフローチャートである。
【図２０】上記パケット送受信制御処理の第６の部分を示すフローチャートである。
【図２１】上記パケット送受信制御処理の第７の部分を示すフローチャートである。
【図２２】上記パケット送受信制御処理の第８の部分を示すフローチャートである。
【図２３】上記パケット送受信制御処理の第９の部分を示すフローチャートである。
【図２４】図２のトラヒックモニタ部１０５内の管理制御部１５１によってＭＡＣ層において割り込み処理で実行される排他的セクタパターン解除処理を示すフローチャートである。
【図２５】図２の上位レイヤ処理装置１０７によってＭＡＣ層において用いられ上位レイヤ処理装置１０７に接続されたテーブルメモリ１０７ａに格納される方位角対受信信号電力値テーブルの一例を示す図である。
【図２６】図１の無線アドホックネットワークのＭＡＣ層において用いられるハローパケットのフォーマットを示す図である。
【図２７】図２の上位レイヤ処理装置１０７によってＭＡＣ層において実行される、自無線局と隣々接無線局との間の距離Ｌｃを計算する処理を説明するための図である。
【図２８】本実施形態におけるサービス提供のイメージ図である。
【図２９】図２の上位レイヤ処理装置１０７によってネットワーク層において用いられ上位レイヤ処理装置１０７に接続されたテーブルメモリ１０７ａに格納される隣接無線局テーブルの一例を示す図である。
【図３０】図２の上位レイヤ処理装置１０７によってネットワーク層において用いられ上位レイヤ処理装置１０７に接続されたテーブルメモリ１０７ａに格納されるトポロジテーブルの一例を示す図である。
【図３１】図２の上位レイヤ処理装置１０７によってネットワーク層において用いられ上位レイヤ処理装置１０７に接続されたテーブルメモリ１０７ａに格納されるルーティングテーブルの一例を示す図である。
【図３２】図２の上位レイヤ処理装置１０７によってネットワーク層において用いられ上位レイヤ処理装置１０７に接続されたテーブルメモリ１０７ａに格納される位置情報推定テーブルの一例を示す図である。
【図３３】図２の上位レイヤ処理装置１０７によってＭＡＣ層において実行される方位角付きトポロジ情報配布処理を示すフローチャートである。
【図３４】図３３のサブルーチンである受信処理（ステップＳ１０３）を示すフローチャートである。
【図３５】図３４のサブルーチンであるルートからの位置情報推定処理（ステップＳ１１５）の第１の部分を示すフローチャートである。
【図３６】図３４のサブルーチンであるルートからの位置情報推定処理（ステップＳ１１５）の第２の部分を示すフローチャートである。
【図３７】図２の上位レイヤ処理装置１０７によってネットワーク層において実行されるトポロジ情報配布処理の一例を示す図であり、（ａ）は無線局１−Ｋからのトポロジ情報の配布を示し、（ｂ）は無線局１−Ｋ及び１−Ｌにおけるトポロジテーブルを示す。
【図３８】図２の上位レイヤ処理装置１０７によってネットワーク層において実行されるトポロジ情報配布処理の一例を示す図であり、（ａ）は無線局１−Ｌでのトポロジ情報の受信を示し、（ｂ）は無線局１−Ｋ及び１−Ｌにおけるトポロジテーブルを示す。
【図３９】図２の上位レイヤ処理装置１０７によってネットワーク層において実行される隣接無線局以外の距離及び方位角の計算処理の一例を示す図であり、（ａ）各無線局の配置関係を示し、（ｂ）は無線局１−Ｌのトポロジテーブルを示す。
【図４０】図２の上位レイヤ処理装置１０７によってネットワーク層において実行される距離計算処理の一例を示す図であり、（ａ）各無線局の配置関係を示し、（ｂ）は無線局１−Ｌのトポロジテーブルを示す。
【図４１】図２の上位レイヤ処理装置１０７においてアプリケーション層で用いられるサービスパケットのフォーマットを示す図である。
【図４２】図２の上位レイヤ処理装置１０７によってアプリケーション層において実行されるサービス処理を示すフローチャートである。
【図４３】図４２のサブルーチンであるサービス発信処理（ステップＳ１４４）を示すフローチャートである。
【図４４】図４２のサブルーチンであるサービス受信処理（ステップＳ１４５）を示すフローチャートである。
【図４５】図４２のサブルーチンであるサービス転送処理（ステップＳ１４６）を示すフローチャートである。
【図４６】図２の上位レイヤ処理装置１０７に接続された液晶ディスプレイ１０７ｂで表示されるルーティングテーブル表示ツールの一例を示す正面図であって、（ａ）は当該表示ツールの外観を示す正面図であり、（ｂ）は当該表示ツールにおいてエリアを分割しないで表示したときの一例であり、（ｃ）は当該表示ツールにおいてエリアを２分割して表示したときの一例であり、（ｄ）は当該表示ツールにおいてエリアを３分割して表示したときの一例である。
【図４７】図２の上位レイヤ処理装置１０７に接続された液晶ディスプレイ１０７ｂで表示されるトポロジ表示ツールの一例を示す正面図であって、（ａ）は当該表示ツールの外観を示す正面図であり、（ｂ）は当該表示ツールの広域表示での図であり、（ｃ）は当該表示ツールの標準表示での図であり、（ｄ）は当該表示ツールの詳細表示での図である。
【図４８】図１の無線アドホックネットワークにおける計算機シミュレーション結果であって、ホップ数に対する方位角の平均誤差及び距離の平均誤差を示すグラフである。
【符号の説明】
１，１−１乃至１−９…無線局、
１０１…可変ビームアンテナ、
１０２…サーキュレータ、
１０３…指向制御部、
１０４…パケット送受信部、
１０５…トラヒックモニタ部、
１０６…回線制御部、
１０７…上位レイヤー処理装置、
１０７ａ…テーブルメモリ、
１０７ｂ…液晶ディスプレイ、
１３０…パケット受信部、
１３１…高周波受信機、
１３２…復調器、
１３３…受信バッファメモリ、
１４０…パケット送信部、
１４１…送信タイミング制御部、
１４２…送信バッファメモリ、
１４３…変調器、
１４４…高周波送信機、
１５１…管理制御部、
１５２…検索エンジン、
１５３…更新エンジン、
１５４…データベースメモリ、
１５５…クロック回路、
１６０…拡散符号発生器。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control method and a control apparatus for a wireless network such as an ad hoc wireless network that performs packet communication in a wireless network such as a wireless LAN provided with a plurality of wireless stations.
[0002]
[Prior art]
In an ad hoc wireless network that wirelessly supports communication between an unspecified number of people who are temporarily gathered in a specific area, users in the network cannot operate without the infrastructure such as an Internet router device. It is necessary to coordinately relay packets and perform routing.
[0003]
As a routing method for an ad hoc wireless network, for example, Non-Patent Document 1 proposes a method of transmitting route search packets to obtain route information (hereinafter, referred to as a first conventional example). However, in the conventional example, since the omnidirectional antenna is used, there is a problem that co-channel interference is likely to occur, a bit error rate (BER) increases, and the number of communication that can be performed simultaneously is limited.
[0004]
In order to solve this problem, for example, using an array antenna control device described in Non-Patent Documents 2 to 4, "Evaluation including signal strength when each adjacent wireless station receives a signal from its own station" Based on the signal from the adjacent radio station including the measured value of the value, the evaluation value including the signal strength as viewed from each adjacent radio station at each azimuth centered on the own station is obtained, and then, each of the adjacent radio stations is determined. For each of the above-mentioned adjacent link state tables, the maximum evaluation value is selected and the affinity with each adjacent radio station is selected, and an adjacent link state table including the affinity and the corresponding azimuth is generated and stored. Based on the above, perform wireless communication with the adjacent wireless station of the other party, generate and store a communication table including the azimuth of each adjacent wireless station that is performing wireless communication with another wireless station, and store the communication table in the communication table. Base station that is in wireless communication with another A wireless signal is transmitted using an exclusive radiation pattern that directs a null point to the azimuth of a line station (hereinafter referred to as a second conventional example). 5 is proposed. According to the control method of the second conventional example, in a wireless network such as a wireless ad hoc network, co-channel interference can be suppressed, and the number of communications that can be performed simultaneously can be increased as compared with the first conventional example. This has the effect that the amount can be increased.
[0005]
[Non-patent document 1]
D. B. Johnson, et al. , "Dynamic Source Routing in Ad Hoc Wireless Networks", in book on "Mobile Computing", Chapter 5, pp. 153-181, Kluer Academic Publishers, 1996.
[Non-patent document 2]
Takashi Ohira, "Toward the Consumerization of Adaptive Antennas", 1999 Symposium of the Association of Electrical Engineers, Kansai Branch, "Recent Microwave and Millimeter-Wave Technologies," S8-1, published by the Institute of Electrical Engineers of Japan, pp. S41, November 14, 1999.
[Non-Patent Document 3]
Takashi Ohira et al., "Adaptive Beamforming by Microwave Signal Processing and Proposal of Electronically Controlled Director (ESPAR) Antenna", IEICE Technical Report, AP99-61, SAT99-61, IEICE Published, pp. . 9-14, July 1999.
[Non-patent document 4]
Satoshi Tano et al., "M-CMA: Digital Signal Processing Algorithm for Adaptive Beamforming by Microwave Signal Processing," IEICE Technical Report, AP99-62, SAT99-62, IEICE, pp. 15-22, July 1999.
[Non-Patent Document 5]
Shingo Horizawa et al., "Performance Evaluation of Multi-hop Ad Hoc Network Considering Adaptive Antenna", IEICE Technical Report, RCS2001-19, CQ2001-19, published by the Institute of Electronics, Information and Communication Engineers, April 2001.
[Non-Patent Document 6]
Yuichiro Ohno et al., "Evaluation of Routing Method Based on Antenna Scan Angle vs. SINR Information", Proceedings of IEICE Society Conference, SB-3-1, published by IEICE, September 2000.
[Non-Patent Document 7]
T. W. Chen et al, "Global State Routing: A New Routing Scheme for Ad-hoc Wireless Networks", Proceedings of IEEE ICC'98, June 1998.
[Non-Patent Document 8]
Yoshihiro Konishi et al., "Basics of Mobile Communication Technology", published by Nikkan Kogyo Shimbun, December 1994.
[0006]
[Problems to be solved by the invention]
By using the wireless ad hoc network shown in the second conventional example, it is possible to provide an information distribution service even in an infrastructureless place or a disaster area. However, there is a problem that the service may not be satisfactorily received because the throughput and the arrival rate decrease and the delay increases as the number of hops increases.
[0007]
The object of the present invention is to solve the above problems, in a wireless network such as an ad hoc wireless network, the user can be satisfied even if the number of hops increases, when a certain user is interested in the information of the service provider, It is an object of the present invention to provide a control method and a control device for a wireless network that can approach the position of the service provider.
[0008]
[Means for Solving the Problems]
A method for controlling a wireless network according to the present invention includes a plurality of wireless stations, and in a method for controlling a wireless network that performs wireless communication between wireless stations,
Transmitting and receiving between the wireless stations a first information table of received signal power values for each predetermined azimuth to each adjacent wireless station within a service area of one wireless station;
Based on the received first information table, a second information table of the azimuth angle and the received signal power value of each adjacent wireless station from the own station and each of the wireless stations within the service area of each adjacent wireless station. Generating a third information table of the azimuth of the adjacent wireless station and the received signal power value and storing the third information table in a storage device;
A step of calculating the number of hops between the adjacent wireless station and the destination wireless station with respect to the destination wireless station based on the predetermined routing criteria based on the second and third information tables and storing the calculated number of hops in the storage device as a fourth information table When,
Based on the second, third, and fourth information tables, the distance, azimuth, and hop number from the own station to each wireless station in the wireless network are calculated and stored in the storage device as a fifth information table. Steps to
Displaying at least one of the distance, the azimuth angle, and the number of hops to each radio station included in the fifth information table.
[0009]
In the method for controlling a wireless network, the displaying may include displaying a position indicating a distance and an azimuth to each wireless station in a topology display format centering on the own station.
[0010]
In the method of controlling a wireless network, the displaying may include displaying the number of hops to each wireless station in a display form of a concentric circle around the own station.
[0011]
Furthermore, the method of controlling a wireless network further includes the step of changing the quality of service that can be transmitted according to the number of hops from the own station to the destination wireless station based on the fifth information table. I do.
[0012]
A wireless network control device according to the present invention includes a plurality of wireless stations, a wireless network control device that performs wireless communication between each wireless station,
Transmitting and receiving a first information table of received signal power values for each predetermined azimuth to each adjacent wireless station in a service area of one wireless station between the wireless stations;
Based on the received first information table, a second information table of the azimuth angle and the received signal power value of each adjacent wireless station from the own station and each of the wireless stations within the service area of each adjacent wireless station. A third information table of the azimuth of the adjacent wireless station and the received signal power value is generated and stored in the storage device,
Based on the second and third information tables, the number of hops to the adjacent wireless station and the destination wireless station with respect to the destination wireless station is calculated based on a predetermined routing criterion, and stored in the storage device as a fourth information table;
Based on the second, third, and fourth information tables, the distance, azimuth, and hop number from the own station to each wireless station in the wireless network are calculated and stored in the storage device as a fifth information table. And
A control means is provided for controlling to display at least one of the distance, the azimuth, and the hop number to each wireless station included in the fifth information table.
[0013]
In the above-mentioned control apparatus for a wireless network, the control means displays a position indicating a distance and an azimuth angle to each wireless station in a topology display format centering on the own station.
[0014]
Further, in the control device for a wireless network, the control means displays the number of hops to each wireless station in a display form of a concentric circle centered on the own station.
[0015]
Further, in the control device for the wireless network, the control means may further change the quality of service that can be transmitted according to the number of hops from the own station to the destination wireless station based on the fifth information table. Features.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
FIG. 1 is a plan view of a plurality of wireless stations 1-1 to 1-9 (generally denoted by reference numeral 1) showing a configuration of an ad hoc wireless network according to an embodiment of the present invention. 2 is a block diagram showing a configuration of each wireless station 1 in FIG.
[0018]
In the wireless communication system of this embodiment, as shown in FIG. 1, a plurality of wireless stations 1 are scattered in a plane, and each wireless station 1 has a gain, a transmission power, a reception sensitivity, Has a predetermined service area determined by parameters such as the above, and can perform packet communication within this service area. When performing packet communication with the wireless station 1 outside the service area, the wireless station 1 within the service area Is used as a relay station to relay the packet data, thereby transmitting the packet data to a desired destination wireless station 1. That is, each wireless station 1 includes a router device that performs packet routing, and operates as a calling terminal, a relay station, or a destination terminal.
[0019]
The wireless communication system according to this embodiment is applied to, for example, a packet communication system of an ad hoc wireless network such as a wireless LAN, and includes an omni pattern that is an omnidirectional radiation pattern and a predetermined pattern in a horizontal plane centered on the own station. A variable beam antenna 101 capable of selectively switching between a sector beam pattern capable of selectively changing a sector-shaped main beam for each azimuth and an exclusive sector pattern capable of forming a null point for each azimuth. Prepare,
(A) Based on an RE (Reply) signal from an adjacent wireless station, including a measured value of a signal power to interference noise power ratio (SINR) when the adjacent wireless station receives an RQ (Request) signal from the own station. An azimuth-to-SINR table (hereinafter referred to as an AS-Table (Angle-SINR Table)) that is created in advance and includes the SINR as seen from the wireless station 1 in the service area for each predetermined azimuth in the horizontal plane centered on the own station. )When,
(B) The maximum SINR is selected for each adjacent wireless station in the AS table, and is set as the affinity (Affinity) with each adjacent wireless station. The affinity, the azimuth angle corresponding to the affinity, and the data update time are displayed. (Hereinafter referred to as an NLS table (Neighbor Link-State Table)).
(C) In the ad-hoc wireless network, an exclusive sector pattern is used to direct a null point for a predetermined standby period to an azimuth of each adjacent wireless station that is communicating with another wireless station other than the own station. A communication table (hereinafter referred to as an OC table (On-going Table)) including an azimuth angle of each adjacent wireless station already in wireless communication with another wireless station, and a standby period end date and time.
Is stored in the database memory 154, and packet communication is performed while controlling the radiation pattern of the variable beam antenna 101 based on the NLS table and the OC table.
[0020]
Next, the device configuration of each wireless station 1 will be described with reference to FIG. 2, a wireless station 1 includes a variable beam antenna 101, a directivity control unit 103 for controlling the directivity thereof, a circulator 102, a data packet transmitting / receiving unit including a data packet transmitting unit 140 and a data packet receiving unit 130. 104, a traffic monitor unit 105, a line control unit 106, and an upper layer processing unit 107.
[0021]
Transmission signal data for communication in packet format generated by the upper layer processing device 107 that processes data to be transmitted / received is input to the modulator 143 via the transmission buffer memory 142, and the modulator 143 transmits a signal of a predetermined radio frequency. The carrier signal is spread-spectrum modulated according to the input communication transmission signal data by using a predetermined communication channel spreading code generated by the CDMA method in the spreading code generator 160, and the modulated transmission signal is transmitted at a high frequency. Device 144. After performing processing such as amplification on the input transmission signal, the high-frequency transmitter 144 transmits the signal from the variable beam antenna 101 to another wireless station 1 via the circulator 102. On the other hand, the reception signal for the communication channel in the packet format received by the variable beam antenna 101 is input to the high-frequency receiver 131 via the circulator 102, and the high-frequency receiver 131 performs low noise amplification on the input reception signal. After the processing of (1) is performed, the output is output to the demodulator 132. Demodulator 132 demodulates the input received signal by spectrum despreading using a spread code for a communication channel generated by CDMA method in spread code generator 160, and demodulates the received signal data after demodulation to an upper layer. Output to the processing device 107 and output to the traffic monitor unit 105 for traffic monitoring.
[0022]
In the present embodiment, the variable beam antenna 101 that is a directional antenna is connected to a plurality of antenna elements and a control unit 103 that controls the directivity thereof,
(A) an omni pattern that is an omnidirectional radiation pattern;
(B) As shown in FIG. 3, for example, a sector beam pattern capable of selectively changing a sector-shaped main beam for each predetermined azimuth in a horizontal plane centered on the own station;
(C) an exclusive sector pattern capable of forming a null point for each azimuth angle;
Is an antenna that can be selectively switched by electrical control. Note that the variable beam antenna 101 may be, for example, a known phased array antenna device, or may be a variable beam antenna disclosed in Non-Patent Documents 2 to 4.
[0023]
The traffic monitor unit 105 includes a search engine 152, an update engine 153, a database memory 154, and a clock circuit 155, executes a packet transmission / reception control process described later, and allows the wireless station 1 to communicate with another wireless station 1. By determining the communication channel to be used in the packet communication and transmitting the designated data of the spreading code corresponding to the determined communication channel to the spreading code generator 160 via the line control unit 106, the spreading code generator 160 By controlling to generate a spreading code corresponding to the designated data and transmitting designated data of a time slot corresponding to the determined communication channel to the transmission timing control unit 141 via the line control unit 106, the transmission timing control unit 141 is the transmission signal data for the communication channel by the transmission buffer memory 142. Controls to transmit the signal for the communication channel by controlling the writing and reading of data is transmitted in the corresponding time slot. The clock circuit 155 measures the current date and time and outputs the information to the management control unit 151 as necessary.
[0024]
The search engine 152 of the traffic monitor unit 105 searches data in the database memory 154 under the control of the management control unit 151 and returns the searched data to the management control unit 151. The update engine 153 updates data in the database memory 154 under the control of the management control unit 151. Further, the database memory 154 includes an AS table, an NLS table, and an OC table, for example, a routing table according to a routing control program (RIP) disclosed in a known RFC, and a memory for temporarily storing data when a radio signal is received. Store the temporary storage table.
[0025]
In the present embodiment, the effective transmission beam width of the sector beam pattern for changing the directivity of the antenna radiation pattern so that the gain in the direction of a single communication partner is maximized is set to 30 degrees. Can be set so that the azimuth can be selectively changed every 30 degrees.
[0026]
Next, a method of creating an AS table will be described. Each wireless station in the ad hoc wireless network periodically collects neighboring wireless station information and generates an AS table. The wireless station of the own station that collects the information of the adjacent wireless stations (hereinafter referred to as a wireless station S) first transmits the broadcast packets in azimuths in 12 directions every 30 degrees according to the sector beam pattern. The azimuth angles are 12 directions so that the sector beam pattern covers all 360 degrees. This packet signal is called an RQ (Request) signal. As shown in FIG. 7, the RQ signal includes a packet type: RQ, an ID (identification number or identification code, the same applies hereinafter) of a transmission source radio station of the RQ signal, a transmission azimuth, and a waiting time (duration; The unit is millisecond). Specifically, the standby time is a time until the transmission of the RQ signal in the 12 directions is completed.
[0027]
7 to 12 show the frame format of each signal used in the MAC layer.
[0028]
Next, a neighboring wireless station (hereinafter, wireless station D) that has received the RQ signal measures the SINR at the time of reception. The wireless station D temporarily stores the value of the SINR in the temporary storage table during the standby time, and after the end of the standby time, as shown in FIG. 8, the packet type: RE, the ID of the destination wireless station, The value of the SINR is returned to the wireless station S, which is the source of the RQ signal, as a unicast packet signal together with the ID of the source wireless station and the azimuth information described in the RQ signal. This packet is called an RE signal. When transmitting the RE signal, the same procedure is performed as in the case of transmitting a normal data packet (the data transmission procedure will be described later).
[0029]
Then, the wireless station S that has received the RE signal extracts the source wireless station ID (here, the ID of the wireless station D), the azimuth information, and the SINR information of the RE signal from the RE signal, and generates an AS table from them. Or update. FIG. 4 shows an example of the AS table of the wireless station S. Here, when a radio station other than the radio station S, that is, a radio station different from the radio station that transmitted the corresponding RQ signal receives the RE signal, the RE signal is ignored. As is clear from FIG. 4, the AS table stores, for each azimuth, SINR data as viewed from each adjacent wireless station.
[0030]
Next, a method of generating an NLS table will be described. Each wireless station selects an azimuth at which the SINR value is maximum for each adjacent wireless station described in the AS table, and sets the SINR value as the affinity with the adjacent wireless station. Each wireless station extracts the azimuth and affinity values for each adjacent wireless station, and generates and updates an NLS table using the current date and time as the update date and time. FIG. 5 shows an example of the NLS table of the wireless station S. As is clear from FIG. 5, the azimuth corresponding to the maximum SINR value, the affinity which is the maximum SINR value, and the update date and time are stored in the NLS table for each adjacent wireless station.
[0031]
In the present embodiment, in order to measure the SINR, the BER is measured by transmitting and receiving a data packet of a predetermined training pattern to and from each of the other wireless stations 1, and the BER with respect to the SINR determined by the modulation / demodulation method of the wireless communication is measured. It is converted to SINR using a characteristic graph. For example, when using the CDMA system, conversion can be performed using a graph of BER characteristics with respect to SINR. For example, when using the QPSK differential detection system, conversion can be performed using a graph of BER characteristics with respect to a predetermined CNR. Can be. That is, whether to use the carrier power to interference noise power ratio (hereinafter, referred to as CINR) or the SINR depends on the modulation / demodulation method used in the wireless system. In the present invention, any measurement value relating to co-channel interference noise may be used.
[0032]
Further, an adaptive MAC (Media Access Control) system used in the present embodiment will be described. In the present embodiment, each wireless station 1 moves around in a two-dimensional closed space, and shares a common wireless channel when performing wireless communication. Each radio station 1 is equipped with a variable beam antenna 101 which is an adaptive antenna capable of forming a 360-degree beam / null point, and the effective transmission beam width is 30 degrees. It is assumed that one wireless station 1 cannot perform transmission and reception at the same time, and cannot perform a plurality of different transmissions and a plurality of different receptions. However, it is possible to transmit the same signal in a plurality of directions. If the direction of the interference wave is known, each receiving wireless station can form or adjust a null point in order to avoid interference due to unnecessary signals.
[0033]
First, a case in which one communication is performed in the ad hoc wireless network will be described. In the idle state in the initial state, each wireless station 1 sets the antenna radiation pattern to an omni pattern, which is a non-directional pattern, and waits for transmission and reception.
[0034]
In the MAC protocol standard of IEEE802.11, which is a wireless LAN standard widely used at present, an RTS-CTS-DATA-ACK exchange procedure is used to realize reliable data communication. On the other hand, in the present system, when the wireless station S wants to perform wireless communication with the wireless station D, the wireless station S first notifies a wireless station adjacent to the wireless station S including the wireless station D “from the wireless station S to the wireless station D. Is transmitted in an omni pattern using an RTS (Request-To-Send) signal. As shown in FIG. 9, the RTS signal includes the packet type: RTS, the ID of the transmission source radio station (here, the ID of the radio station S, as shown in FIG. 9), similarly to the signal specified in IEEE 802.11 and the RE signal of the present system. ), The ID of the destination wireless station (here, the ID of the wireless station D), and the value of the standby time. All adjacent radio stations of the radio station S (the directions to the radio station S are known from their AS and NLS tables) receive the RTS signal from this radio station S.
[0035]
When the wireless station D that is the destination wireless station of the RTS signal receives the RTS signal, the wireless station D transmits a CTS (Clear- To-Send) signal is returned in an omni pattern. As shown in FIG. 10, the CTS signal includes the packet type: CTS, the ID of the destination wireless station (here, the ID of the wireless station S), and the value of the standby time.
[0036]
Next, when the wireless station S that has transmitted the RTS signal receives the CTS signal from the wireless station D that is the destination, the wireless station S transmits the DATA signal. The wireless station D, which is the destination wireless station, receives the DATA signal, and returns an ACK (Acknowledgement) signal (acknowledgment signal) to the wireless station S as an acknowledgment when the reception is completed normally. Upon receiving the ACK signal, the wireless station S completes a series of processes for one DATA, and returns to the idle state. Here, as shown in FIG. 11, the DATA signal includes the packet type: DATA, the ID of the source wireless station (here, the ID of the wireless station S), and the ID of the destination wireless station (here, the wireless station D of the wireless station D). ID), the value of the standby time, and the data to be transmitted. As shown in FIG. 12, the ACK signal includes the packet type: ACK, the ID of the destination wireless station (here, the ID of the wireless station S), and the value of the standby time.
[0037]
On the other hand, when a wireless station other than the wireless station D (hereinafter, wireless station A) receives the RTS signal, the wireless station A is the source wireless station of the RTS signal based on the AS table and the NLS table. The azimuth information of the wireless station S is acquired, and a null point is formed in the direction of the wireless station S only during the standby time described in the RTS signal. Such an antenna radiation pattern in which a null point is formed in an arbitrary direction is collectively called an exclusive sector pattern. At this time, the wireless station A and the wireless station (here, the wireless station S) that have caused a null point in its own OC table, the azimuth in that direction, and the standby time period end date and time when the standby time ends ( = Current date and time + standby time). FIG. 6 shows an example of the OC table.
[0038]
When a station other than the wireless station S receives the CTS signal, a null point is formed for a certain period in the direction of the CTS signal transmitting wireless station in the same manner as in the case of the RTS signal.
[0039]
The wireless station S that has transmitted the RTS signal and the DATA signal and the wireless station D that has transmitted the CTS signal operate a timer for a fixed time after the transmission. In the case of the radio station S, if the CTS signal is not received within a certain time after the transmission of the RTS signal, or if the ACK signal is not received within a certain time after the transmission of the DATA signal, the RTS signal transmission processing is performed assuming that the time-out has occurred. Repeat the series of processing from. On the other hand, when the wireless station D does not receive the DATA signal within a certain period of time after transmitting the CTS signal, the sector beam pattern to the wireless station S is returned to the omni pattern, and the wireless station D enters an idle state. When the waiting time period ends, based on the entry in the corresponding OC table, if there is no other communication during the waiting time period in that direction, the null point of the variable beam antenna 101 in that direction is released.
[0040]
Next, a case in which it is already known that another communication is being performed will be described. FIG. 13 shows a case where a wireless station X and a wireless station Y near the wireless station S and a wireless station D are trying to communicate with the wireless station X as a transmission source during communication. The sector beam pattern from the wireless station S to the wireless station D is as shown in FIG. Here, the radio stations X and Y have already received the RTS signal and the CTS signal from the radio stations S and D, and have registered them in the OC table. Where γ_xyIs the value of the azimuth angle from the radio station X to the radio station Y, the radio station X and the radio station Y have the azimuth γ from the respective AS table and NLS table._xsAnd γ_xd, The radio station Y has an azimuth γ_ysAnd γ_ydYou can know the value of First, when the transmission of the RTS signal from the radio station X to the radio station Y affects the radio stations S and D, that is, the azimuth γ_xyIs γ_xsOr γ_xdIn this case, the wireless station X cannot transmit, and it is necessary to wait for the communication between the wireless station S and the wireless station D to end in the idle state. Otherwise, radio station X can transmit an RTS signal. At this time, the antenna radiation pattern of the radio station X is based on the assumption that the azimuth γ_xsAnd γ_xdIs an exclusive sector pattern in which a null point is formed in the direction of.
[0041]
Similarly, when the exclusive sector pattern from the wireless station Y to the wireless station X does not capture the wireless station S or the wireless station D, that is, the azimuth γ_yxAnd γ_ysOr γ_ydIf do not overlap, wireless station Y can transmit a CTS signal to wireless station X. Thereafter, the wireless station X and the wireless station Y transmit and receive the DATA signal and the ACK signal according to the sector beam pattern.
[0042]
FIGS. 15 to 23 are flowcharts showing a packet transmission / reception control process executed in the MAC layer by the management control unit 151 in the traffic monitor unit 105 in FIG.
[0043]
First, in step S1 of FIG. 15, based on the OC table, when the other wireless station is not communicating or does not know it, the antenna radiation pattern is set to the omni pattern, and the other wireless station is communicating. After setting the antenna radiation pattern to the exclusive sector pattern, the system enters an idling state in step S1A, and it is determined in step S2 whether a packet transmission or reception event has occurred. If YES, the process proceeds to step S3. If NO, the process returns to step S1. Next, in step S3, it is determined whether the packet is to be transmitted or received. If the packet is transmitted, the process proceeds to step S4, while if the packet is received, the process proceeds to step S21 in FIG. In step S4, it is determined whether to transmit the RQ signal or the transmission of the DATA signal or the RE signal. If the transmission is the transmission of the RQ signal, the process proceeds to step S5. Proceed to step S11. Further, in step S5, the azimuth angle ANG of the variable beam antenna 101 is initialized to 0 degree, and in step S6, the RQ signal is transmitted in the sector beam pattern with respect to the specified azimuth angle ANG (degree), and in step S7, It is determined whether the transmission of the RQ signals to all the azimuths has been completed. If NO, the process proceeds to step S8, while if YES, the process returns to step S1. In step S8, the azimuth angle ANG (degree) is incremented by 30 degrees, and the process returns to step S6. Therefore, in the processing of steps S6 to S8, the RQ signal is transmitted over all the azimuths in the sector beam pattern while incrementing the azimuth ANG of the variable beam antenna 101 by 30 degrees. In the present embodiment, while the azimuth angle ANG of the variable beam antenna 101 is incremented by 30 degrees and the RQ signal is transmitted over all azimuth angles in the sector beam pattern, this is an example, and the present invention Instead, the azimuth angle ANG of the variable beam antenna 101 may be incremented by a predetermined angle.
[0044]
FIG. 16 shows transmission / reception processing of the RTS signal and the CTS signal. First, in step S11, an adjacent wireless station to the destination wireless station (including the destination wireless station in the case of direct transmission) is obtained from the routing table. In step S12, the OC table is checked to see if the azimuth to the adjacent radio station described in the NLS table overlaps with the azimuth of the entry in the OC table. In step S13, the azimuth to the adjacent radio station is stored in the OC table. It is determined whether the azimuth does not overlap with the azimuth to a certain entry. If YES, the process proceeds to step S14, and if NO, the process proceeds to step S18. In step S14, the RTS signal is transmitted to the adjacent wireless station in an omni pattern or exclusive sector pattern pattern based on the OC table. In step S15, it is determined whether the CTS signal addressed to the own station has been received without a CTS timeout. If YES, the process proceeds to step S16, while if NO, the process proceeds to step S18. In step S16, a DATA signal or RE signal is transmitted to the adjacent wireless station in a sector beam pattern of the azimuth angle described in the NLS table, and in step S17, whether or not the ACK signal addressed to the own station has been received without ACK timeout. Is determined, the process returns to step S1 in FIG. 15 if YES, and proceeds to step S18 if NO. In step S18, after waiting for a random time, the process returns to step S1 in FIG.
[0045]
FIG. 17 shows a branching process based on the packet type of the received packet signal. First, in step S21, it is determined whether or not the packet type of the received packet signal is RQ. If YES, step S31 in FIG. On the other hand, if NO, the process proceeds to step S22. In step S22, it is determined whether the packet type of the received packet signal is RE. If YES, the process proceeds to step S41 in FIG. 19, while if NO, the process proceeds to step S23. In step S23, it is determined whether or not the packet type of the received packet signal is RTS. If YES, the process proceeds to step S51 in FIG. 20, while if NO, the process proceeds to step S24. In step S24, it is determined whether the packet type of the received packet signal is CTS. If YES, the process proceeds to step S61 in FIG. 21, while if NO, the process proceeds to step S25. In step S25, it is determined whether the packet type of the received packet signal is DATA. If YES, the process proceeds to step S71 in FIG. 22, while if NO, the process proceeds to step S26. In step S26, it is determined whether the packet type of the received packet signal is ACK. If YES, the process proceeds to step S81 in FIG. 23, while if NO, the process returns to step S1 in FIG.
[0046]
FIG. 18 shows a process for the received RQ signal. First, in step S31, the ID, the transmission azimuth, and the standby time of the transmission source radio station are acquired from the received RQ signal, and the transmission source radio station and the SINR value detected at the time of reception are acquired. After temporarily storing the standby time in the temporary storage table for each station and starting the standby time timer in which the obtained standby time is set, it is determined in step S32 whether or not the standby time timer has expired. If the answer is NO, the process proceeds to step S34. In step S33, an RE signal is created based on the set (one or more) of the transmission azimuth information and the SINR value stored in the temporary storage table for each RQ signal transmission source wireless station, and the process proceeds to transmission processing. It returns to step S1 of FIG. On the other hand, in step S34, it is determined whether an RQ signal from the same transmission source wireless station has been received. If YES, the process proceeds to step S35, while if NO, the process returns to step S32. This is to prevent the reception of the RQ signal from another wireless station until the reception of the RQ signal from the same wireless station is completed. Next, the transmission azimuth and the standby time are acquired from the received RQ signal in step S35, and temporarily stored in the temporary storage table for each transmission source radio station together with the SINR value at the time of reception. The standby time timer in which the time is set is restarted, and the process returns to step S32.
[0047]
FIG. 19 shows the processing of the received RE signal. In step S41, the source radio station of the RE signal, the set of the azimuth information and the SINR value are acquired from the received RE signal, the AS table is updated, and the NLS table is updated. Update. If the table is new, each table is newly created. Next, the process returns to step S1 in FIG.
[0048]
FIG. 20 shows the processing of the received RTS signal. First, in step S51, it is determined whether the received RTS signal is an RTS signal addressed to itself. If YES, the process proceeds to step S52, while if NO, the process proceeds to step S56. Proceed to. Next, in step S52, the CTS signal is transmitted to the adjacent wireless station that is the source of the RTS signal in the omni pattern or the exclusive sector pattern pattern based on the OC table. It is determined whether a DATA signal has been received. If the determination is YES, the process proceeds to step S54, whereas if the determination is NO, the process proceeds to step S55. After transmitting an ACK signal to the adjacent wireless station in the sector beam pattern of the azimuth described in the NLS table in step S54, the process returns to step S1 in FIG. On the other hand, after waiting for a random time in S55, the process returns to step S3 in FIG.
[0049]
In step S56, it is determined in the NLS table whether or not there is a source radio station of the received RTS signal. When YES, the source radio station of the received RTS signal is an adjacent radio station, On the other hand, if NO in step S57, the source radio station of the received RTS signal is not an adjacent radio station or does not know it, and the flow proceeds to step S59. In step S57, in the OC table, the source wireless station of the received RTS signal, the azimuth information for the source wireless station described in the NLS table, and the end date and time of the standby period (= current date and time + standby described in the RTS signal) 15) is stored, and in step S58, the antenna pattern of the variable beam antenna 101 is set to an exclusive sector pattern pattern in which a null point is formed in the azimuth direction to the transmission source radio station of the RTS signal, and then the step of FIG. Return to S1. On the other hand, in step S59, after waiting unconditionally for the standby time described in the RTS signal, the process returns to step S3 in FIG.
[0050]
FIG. 21 shows processing of the received CTS signal. First, in step S61, it is determined in the NLS table whether or not there is a transmission source radio station of the received CTS signal. When the radio station is an adjacent radio station, the process proceeds to step S62. On the other hand, when NO, the transmission source radio station of the received CTS signal is not an adjacent radio station or does not know it. move on. In step S62, in the OC table, the source wireless station of the CTS signal, the azimuth information for the source wireless station described in the NLS table, and the end date and time of the standby period (= current date and time + standby time described in the CTS signal) ) Is stored, and the antenna pattern of the variable beam antenna 101 is set to an exclusive sector pattern pattern in which a null point is formed in the azimuth direction to the transmission source wireless station of the CTS signal in step S63. Return to On the other hand, in step S64, after waiting unconditionally for the standby time described in the CTS signal, the process returns to step S3 in FIG.
[0051]
FIG. 22 shows processing of the received DATA signal. First, in step S71, it is determined in the NLS table whether or not there is a source wireless station of the received DATA signal. If YES, the source of the received DATA signal is determined. When the wireless station is an adjacent wireless station, the process proceeds to step S72. On the other hand, when NO, the source wireless station of the received DATA signal is not an adjacent wireless station or does not know this, and the process proceeds to step S74. move on. In step S72, in the OC table, the source radio station of the DATA signal, the azimuth information for the source radio station described in the NLS table, and the end date and time of the standby period (= current date and time + standby time described in the DATA signal) ) Is stored, and the antenna pattern of the variable beam antenna 101 is set in step S73 to an exclusive sector pattern pattern in which a null point is formed in the azimuth direction to the transmission source radio station of the DATA signal, and then, in step S1 in FIG. Return to On the other hand, in step S74, after waiting unconditionally for the waiting period described in the DATA signal, the process returns to step S3 in FIG.
[0052]
FIG. 23 shows processing of the received ACK signal. First, in step S81, it is determined whether or not there is a transmission source radio station of the received ACK signal in the NLS table. If YES, the transmission source of the received ACK signal is determined. When the radio station is an adjacent radio station, the process proceeds to step S82, while when NO is determined, the transmission source radio station of the received ACK signal is not an adjacent radio station, or when it is unknown, the process proceeds to step S84. move on. In step S82, in the OC table, the source wireless station of the ACK signal, the azimuth information for the source wireless station described in the NLS table, and the end date and time of the standby period (= current date and time + standby time described in the ACK signal) ) Is stored, and in step S83, the antenna pattern of the variable beam antenna 101 is set to an exclusive sector pattern pattern in which a null point is formed in the azimuth direction to the transmission source wireless station of the ACK signal, and then, is set in step S1 of FIG. Return to On the other hand, after waiting unconditionally for the waiting period described in the ACK signal in step S84, the process returns to step S3 in FIG.
[0053]
FIG. 24 is a flowchart showing an exclusive sector pattern release process executed in the interrupt process by the management control unit 151 in the traffic monitor unit 105 of FIG.
[0054]
In FIG. 24, first, it is determined in the OC table whether or not there is a wireless station whose standby period has ended in the OC table. If YES, the process proceeds to step S92, whereas if NO, the process returns to step S91. Next, in step S92, the null point for the corresponding wireless station is canceled to release the exclusive sector pattern pattern corresponding to the null point. In step S93, the data in the OC table for the corresponding wireless station is deleted, and the process returns to step S91. .
[0055]
FIG. 14 is a diagram showing an antenna radiation pattern in each state for each signal used in the ad hoc wireless network of FIG.
[0056]
As is clear from FIG. 14, when there is no existing communication, or when the wireless station does not recognize the existing communication, all transmission and reception of the RTS signal and the CTS signal are performed using the omni pattern. When transmitting and receiving the DATA signal and the ACK signal, the transmitting wireless station or the receiving wireless station uses a sector beam pattern, but the wireless station in an idle state has an exclusive sector pattern. On the other hand, when it is already known that another communication is being performed, the transmission and reception of the RTS signal and the CTS signal are all performed using the exclusive sector pattern. When transmitting and receiving the DATA signal and the ACK signal, the transmitting wireless station or the receiving wireless station uses a sector beam pattern, but the wireless station in an idle state has an exclusive sector pattern.
[0057]
To summarize the control operation of the present embodiment, it is assumed that the wireless station X wants to communicate with the wireless station Y, and N wireless stations #n₁, N₂, ..., n_N｝ Is a set of adjacent radio stations of X for which a communication process is already in progress. Similarly, M radio stations {m₁, M₂, ..., m_M｝ Is a set of adjacent wireless stations in Y for which a communication process is already in progress. In this case, the conditions under which the radio stations X and Y can start communication are as follows.
(1) The directional beam from X to Y has N radio stations ｛n₁, N₂, ..., n_NIf you do not capture｝. That is, the beam azimuth γ from the X direction to the Y direction_xyThe area covered by azimuth γ_xn1, Γ_xn2,…, Γ_xnNDoes not overlap with the area covered by.
(2) The directional beam from Y to X has M radio stations {m₁, M₂, ..., m_MIf you do not capture｝. That is, the beam azimuth γ from the X direction to the Y direction_yxThe area covered by azimuth γ_ym1, Γ_ym2,…, Γ_ymMDoes not overlap with the area covered by.
[0058]
Therefore, X and Y respectively transmit the RTS signal / CTS signal in the selected direction and form a null point in the direction of the radio station having the process currently communicating. Other idle radio stations in the range covered by the XY sector beam pattern wait in an exclusive sector pattern with null points in the X and Y directions based on the OC table. Will be.
[0059]
In the above, the processing in the MAC layer and the operation of the wireless station 1 in the wireless ad hoc network of FIG. 1 have mainly been described. In the following, the network layer and the AS executed using the AS table acquired in the MAC layer are described. The processing in the application layer will be described below. In the following description, an adjacent wireless station refers to a wireless station within its own service area, and an adjacent wireless station refers to an adjacent wireless station of an adjacent wireless station.
[0060]
As described in the section of the related art, by using the wireless ad hoc network, it is possible to provide an information distribution service even in an infrastructureless place (a place without a wireless communication base) or a disaster area, Every time the number of hops increases, the throughput and the arrival rate decrease and the delay increases, so that the service may not be satisfactorily received. For example, when the array antenna device (directional antenna) variable beam antenna 101 described in Non-Patent Documents 2 to 4 is used, the azimuth information of adjacent wireless stations can be known, and the information is exchanged together with the topology information. This makes it possible to construct a topology with azimuth information. It is considered that the usability (usability) is improved by the user using the created topology.
[0061]
In the present embodiment, a method for constructing a topology with an azimuth using the variable beam antenna 101 and a service method using the topology are proposed. In a wireless LAN system conforming to the IEEE 802.11 standard, which is widely used at present, throughput decreases as the number of hops increases, and the packet arrival rate also deteriorates. In other words, as the number of hops increases, it becomes difficult to secure a band, and the quality of service provided becomes worse. Therefore, a wireless network according to the present embodiment (hereinafter, referred to as a firefly net) is proposed as one of the service providing methods of the ad hoc network.
[0062]
The firefly net according to the present embodiment obtains the direction of an adjacent wireless station by using a MAC method using a variable beam antenna 101 which is a directional antenna, and distributes the information as topology information of a routing protocol to obtain an orientation. This is a wireless ad-hoc network that builds cornered topology information and enables position estimation of other wireless stations. In addition, it has a function of changing service quality according to the number of hops when actually providing a service. For example, when a certain user is interested in the information of the service provider, a position estimation display function for estimating and displaying the position of the radio control station of the service provider on the liquid crystal display 107b of the upper layer processing device 107 is used. Can be easily approached. In addition, it is considered that as the number of hops to the service provider is smaller, if a high-quality service is provided, the user's merit increases by approaching the service provider.
[0063]
As the MAC system for controlling the variable beam antenna 101 used in the firefly net according to the present embodiment, the following two operation phases are utilized by using the above-described packet transmission / reception control processing in the MAC layer (FIGS. 15 to 24). Having.
[0064]
(A) Adjacent wireless station scanning phase: Each wireless station transmits a packet of an RQ signal using the variable beam antenna 101 and performs a 360-degree scan at regular intervals. Upon receiving the RQ signal packet, the wireless station obtains the received signal power value at the time of reception, adds the information and the transmission azimuth information included in the RQ signal packet, and responds using the RE signal packet. After receiving the RE signal packet, the source of the RQ signal packet receives the azimuth versus received signal power as shown in FIG. 25 based on the received signal power value and the azimuth information added to the RE signal packet. A value table is created and stored in a table memory 107a connected to the upper layer processing device 107. In the azimuth-versus-received-signal power value table of FIG. 25, the received signal power values viewed from each adjacent wireless station are stored in a table format with respect to the azimuth every 30 degrees from the own wireless station.
[0065]
(B) Data communication phase: The beam azimuth used for the wireless station 1 to which data is to be transmitted is extracted from the azimuth versus received signal power value table, and the RTS signal is transmitted for the azimuth. Upon receiving the RTS signal, the destination radio station looks at the source address of the RTS signal, obtains an azimuth from the azimuth versus received signal power value table, and uses the variable beam antenna 101 for the obtained azimuth to obtain a CTS. Send a signal. The DATA signal and the ACK signal perform communication in the same manner as described above.
[0066]
A routing protocol is necessary for efficient multi-hop communication in an ad hoc network in which wireless stations move, but the firefly net according to the present embodiment aims at constructing an azimuth-oriented topology. GSR (Global State Routing; see, for example, Non-Patent Document 7), which is a routing protocol, is used. In addition, in order to construct topology information with an azimuth, information of the azimuth versus received signal power value table is added to the hello packet.
[0067]
FIG. 26 shows the frame format of the hello packet used in the present embodiment. In FIG. 26, following the header including the packet length, for each destination address (the IP address of the destination wireless station), the sequence number, the number of adjacent wireless stations, and the number of adjacent wireless stations corresponding to the number of adjacent wireless stations The azimuth for the address and the received signal power value are stored.
[0068]
Next, construction of the azimuth-attached topology information will be described. The routing protocol used in the present embodiment provides information on the adjacent wireless stations of all the wireless stations in the wireless network, and information on the azimuth versus received signal power value table between the wireless stations, so that the distance between the wireless stations is calculated. Becomes possible. Received signal power value (power intensity) P_RThe relationship between the distance d and the distance d can be represented as the n-th power of the distance by normalization as follows (for example, see Non-Patent Document 8).
[0069]
(Equation 1)
P_R[MW] = γd^-N
[0070]
Here, γ is a constant determined in advance by the transmission power of each wireless station 1, the antenna gain, and the like. Further, n is generally n = 2. The distance and the angle between the own radio station and the adjacent radio station (neighboring radio station) can be calculated based on the cosine theorem, and the following formula is used.
[0071]
(Equation 2)

[0072]
In the example of FIG. 27, the wireless station adjacent to the own wireless station 1-N is 1-M, and the wireless station 1-L is located at a wireless station (adjacent wireless station) that cannot directly communicate. It can be seen from the above that the angle (1-L)-(1-M)-(1-N) is 120 degrees. Further, since the distances La and Lb can be calculated by the above equation (1), the remaining distance Lc can be calculated by the above equation (2). Similarly, the angle (1-N)-(1-L)-(1-M) and the angle (1-L)-(1-N)-(1-M) can be calculated. ing. After calculating the azimuths and distances of the adjacent wireless stations in this way, calculating the azimuths beyond them, it is possible to calculate the azimuths from the own wireless station to all the wireless stations. .
[0073]
Further, a service providing method used in the present embodiment will be described below. When a service (moving image, still image, audio, text data, or the like) is actually provided, the service quality is changed according to the number of hops from the service provider's wireless station (for example, see FIG. 28). For example, the service content is changed as follows.
(A) Providing high-quality services (for example, providing all services including moving images) within one hop from the service provider's wireless station.
(B) Within 2 to 3 hops from the wireless station of the service provider → Providing a medium quality service (for example, providing a still image or audio only service).
(C) Four or more hops from the service provider's radio station → Provision of low-quality service (for example, provision of a service using only voice or text data).
[0074]
With the above-described configuration, it is possible to change the service quality on the information receiving side, and it is possible to receive a service of even higher quality by approaching if the content is interesting. Further, by keeping away information that is not interesting, it is less necessary to receive and transfer useless information. Note that the above example of the number of hops is an example, and the example of FIG. 28 is executed as follows.
(A) The service area S within one hop from the wireless station 1-H of the service provider_HIn the service area S_HIs provided for each wireless station 1-h.
(B) Service area S within 2 hops from service provider's wireless station 1-H_M1, S_M2In the service area S_M1, S_M2Is provided to each of the wireless stations 1-m.
(C) Service area S within 3 hops from radio station 1-H of service provider_L1, S_L2, S_L3In the service area S_L1, S_L2, S_L3Is provided to each of the wireless stations 1-l.
[0075]
FIG. 29 is a diagram showing an example of an adjacent wireless station table used in the network layer by the upper layer processing device 107 of FIG. 2 and stored in the table memory 107a connected to the upper layer processing device 107. As shown in FIG. 29, the adjacent wireless station table stores information on the azimuth and the received signal power value for each adjacent wireless station name.
[0076]
FIG. 30 is a diagram showing an example of a topology table used in the network layer by the upper layer processing device 107 of FIG. 2 and stored in the table memory 107a connected to the upper layer processing device 107. As shown in FIG. 30, the topology table stores information on the azimuth and the received signal power value for each adjacent wireless station for each name of each adjacent wireless station.
[0077]
FIG. 31 is a diagram showing an example of a routing table used in the network layer by the upper layer processing device 107 of FIG. 2 and stored in the table memory 107a connected to the upper layer processing device 107. As shown in FIG. 31, the routing table stores the adjacent wireless station and the number of hops to the destination wireless station for each destination wireless station when routing from the own wireless station to the destination wireless station.
[0078]
FIG. 32 is a diagram showing an example of the position information estimation table used in the network layer by the upper layer processing device 107 of FIG. 2 and stored in the table memory 107a connected to the upper layer processing device 107. As shown in FIG. 32, the position information estimation table stores, for each wireless station recognized in the wireless ad hoc network, a distance from the own wireless station, an azimuth angle, and the number of hops.
[0079]
FIG. 33 is a flowchart showing the azimuth-attached topology information distribution processing executed in the MAC layer by the upper layer processing device 107 in FIG. In FIG. 33, NOSYNC, ASYNC, and SYNC refer to the following states.
(A) NOSYNC: In an initial state, there is no information on the wireless station in the topology table of the own station, and there is no information on the own wireless station in the topology information of the adjacent wireless station obtained from the hello packet from the adjacent wireless station. Say the case.
(B) ASYNC: A case where there is information of another wireless station in the topology table of the own station, but there is no information of the own wireless station in the topology information of the adjacent wireless station obtained from a hello packet from the adjacent wireless station.
(C) SYNC: This refers to a case where information of another wireless station is present in the topology table of the own station, but information of the own wireless station is also present in topology information of the adjacent wireless station obtained from a hello packet from the adjacent wireless station.
[0080]
The hello packet causes an event to be periodically transmitted at a predetermined cycle in each wireless station 1, and transmits a hello packet when a received carrier is not received by carrier sense.
[0081]
In step S101 of FIG. 33, first, it is determined whether or not an event of transmitting a hello packet has occurred. If YES, the process proceeds to step S104, whereas if NO, the process proceeds to step S102. In step S102, it is determined whether or not an event of receiving a hello packet has occurred. If YES, the process advances to step S103 to execute the receiving process in FIG. 34, and then returns to step S101. If NO in step S102, the process returns to step S101. Next, in step S104, the azimuth and the received signal power information of the adjacent wireless station are acquired based on the azimuth versus received signal power value table, and the process proceeds to step S105. In step S105, it is determined whether or not it is NOSYNC. If YES, the process proceeds to step S109, while if NO, the process proceeds to step S106. In step S106, the acquired information is registered in the adjacent wireless station table, and in step S107, it is determined whether or not it is ASYNC. If YES, the process proceeds to step S109. Proceed to S108. In step S108, after the acquired information is registered in the topology table, the process proceeds to step S109. Further, in step S109, a hello packet is generated based on the topology table, the hello packet generated in step S110 is transmitted by broadcast, and the process returns to step S101.
[0082]
FIG. 34 is a flowchart showing the receiving process (step S103) which is a subroutine of FIG.
[0083]
In step S111 of FIG. 34, the transmission source IP address of the received hello packet is registered in the adjacent wireless station table, and it is determined whether or not it is SYNC in step S112. If YES, the process proceeds to step S114. If so, the process proceeds to step S113. In step S113, the received information is registered in the topology table, and in step S114, the shortest hop route is extracted based on the Disixtra method. Next, the route extracted in step S115 is registered in the routing table, and in step S116, the process of estimating the position information from the route in FIG. 35 is executed, and the process returns to the original main routine.
[0084]
Note that the extraction processing of the shortest hop route based on the dissikstra method in step S114 is executed as follows.
<Step SS1> An arbitrary destination wireless station is selected from the topology table.
<Step SS2> All link information including the own radio station is extracted from the topology table.
<Step SS3> The extracted link information is held as a “temporary route”, and even one hop is treated as a route.
<Step SS4> Check whether there is any destination wireless station in each "temporary route". If there is a destination wireless station, the process proceeds to step SS6. If there is no destination wireless station, all link information including the end wireless station of each "temporary route" is extracted from the topology table.
<Step SS5> The extracted link information is added to each "temporary route", held as a new "temporary route", and the process proceeds to step SS4. If there is no link information including the end point radio station of the "temporary route", it is determined that it is unreachable and the process proceeds to step SS6.
<Step SS6> It is checked whether all the destination wireless stations have been selected from the topology table. If it has not been performed, the process proceeds to step SS1, while if it has been performed, the process ends.
[0085]
FIG. 35 and FIG. 36 are flowcharts of the position information estimating process from the route (step S115) which is a subroutine of FIG. When the position information estimating process is executed, the tables in FIGS. 29 to 31 are referred to.
[0086]
In step S121 in FIG. 35, one unselected adjacent wireless station is selected from the adjacent wireless station table, and in step S122, information on the adjacent adjacent wireless station is acquired from the one adjacent wireless station selected from the topology table. . Next, in step S123, the angle between the selected wireless station and the adjacent wireless station in the selected adjacent wireless station is calculated based on the acquired information. The distance to the indirect wireless station is calculated. Further, in step S125, the azimuth between the own radio station and the adjacent radio station is calculated using the cosine theorem as described above, and the information calculated in step S126 is registered in the position information estimation table. In step S127, it is determined whether or not processing has been performed for all adjacent wireless stations. If YES, the process proceeds to step S131 in FIG. 36, while if NO, the process returns to step S121.
[0087]
In step S131 of FIG. 36, the hop number parameter n is set to 2, and in step S132, one unselected wireless station n hops away is selected from the topology table, and information of the wireless station selected in step S133 is stored in the topology table. To get from. Next, in step S134, the angle between the own wireless station and the selected n-hop wireless station in the adjacent wireless stations is calculated, and in step S135, the distance between the own wireless station and the selected n-hop wireless station is calculated. . Further, in step S136, the azimuth of the selected n-hop wireless station from the own wireless station is calculated. Then, the information calculated in step S137 is registered in the position information estimation table, and the process proceeds to step S138. In step S138, it is determined whether or not processing has been performed for all wireless stations n-hop ahead. If YES, the process proceeds to step S139. If NO, the process returns to step S132, and the above process is repeated. In step S139, it is determined whether or not n> Nmax (Nmax is the maximum number of hops in the wireless ad hoc network). If YES, the process returns to the main routine. If NO, however, the process returns to step S140. After incrementing the hop number parameter n by 1, the process returns to step S132.
[0088]
Next, an example of processing in the network layer will be described below with reference to FIGS. In the topology information distribution process of FIG. 37, azimuth information and distance information are distributed to peripheral wireless stations, that is, topology information is distributed periodically. Next, in the topology information distribution process in FIG. 38, azimuth information and distance information are distributed to peripheral wireless stations (here, peripheral wireless stations refer to wireless stations other than the local station). At the time of receiving such information, it extracts other than the adjacent wireless station, calculates the azimuth angle to the extracted wireless station, and additionally registers it in the topology table. Also, in the distance and azimuth calculation processing of the other than the adjacent radio station in FIG. 39, the distance Lc is calculated by the following equation using the cosine theorem.
[0089]
(Equation 3)
Lc²
= La²+ Lb²-2 ・ La ・ Lb ・ cosθ
= 169 + 225-2 x 13 x 15 x (-0.5)
(Equation 4)
Lc = 24.26932219902331939810631617333811
(Equation 5)
Lc ≒ 24.3
[0090]
Further, in the distance calculation processing of FIG. 40, the azimuth θ is calculated using the cosine theorem as in the following equation.
[0091]
(Equation 6)
Lc²= La²+ Lb²-2 ・ La ・ Lb ・ cosθ
225 = 589 + 169−2 × 13 × 24.3 × cos θ
(Equation 7)
cos θ
= 0.8436362991796574325102828806584362
(Equation 8)
θ ≒ 32 degrees
[0092]
Further, processing of the application layer for changing the service quality according to the number of hops according to the present embodiment will be described in detail below.
[0093]
FIG. 41 shows a format of a service packet used in this processing, which is used in the application layer in the upper layer processing device 107 in FIG. In the service packet of FIG. 41, a service distribution range and service data are stored for each service, following a service ID and a transmission source address (radio station address) to which a serial number for service identification is assigned. Here, SN1 and SN2 indicate a serial number of each service. Further, the maximum number of hops is stored in the service distribution range, and the range to which the corresponding service data is distributed is indicated by this information. For example, by default, the maximum number of hops is 1 for high-quality services such as video, the maximum number of hops is 3 for medium-quality services such as still images, and low-quality services such as voice and text data. The maximum number of hops is 4 or more. Further, the service data SN1 is, for example, a moving image, the service data SN2 is a still image, and the service data SN3 is voice or text data. Thereby, the quality of data distributed in each service distribution range can be changed.
[0094]
FIG. 42 is a flowchart showing service processing executed in the application layer by the upper layer processing device 107 in FIG.
[0095]
In step S141 of FIG. 42, it is first determined whether or not a service transmission event has occurred. If YES, the process proceeds to step S144. After performing the service transmission process of FIG. 43, the process returns to step S141. If NO, the process proceeds to step S142. Next, it is determined whether or not a service reception event has occurred in step S142. If YES, the process proceeds to step S145. After performing the service reception process of FIG. 44, the process returns to step S141. If NO in step S142, Proceed to step S143. Further, it is determined whether or not a service transfer event has occurred in step S143. If YES, the process proceeds to step S146. After performing the service transfer process of FIG. 45, the process returns to step S141. If NO in step S143, It returns to step S141.
[0096]
FIG. 43 is a flowchart showing the service transmission process (step S144) which is a subroutine of FIG.
[0097]
In step S151 of FIG. 43, first, a service ID is acquired and stored in a service packet. In step S152, the IP address of the own radio station is acquired and stored in the service packet. Next, in step S153, it is determined whether or not one or more wireless stations exist one hop ahead in the position information estimation table. If YES, the process proceeds to step S154, whereas if NO, the process proceeds to step S159. In step S154, high-quality service data and a high-quality service distribution range are obtained and stored in a service packet. In step S155, whether or not one or more wireless stations exist two and three hops ahead in the position information estimation table If YES, the process proceeds to step S156, while if NO, the process proceeds to step S159. Further, in step S156, the medium-quality service data and the medium-quality service distribution range are acquired and stored in a service packet. In step S157, whether or not one or more wireless stations exist four hops ahead in the position information estimation table is determined. Is determined, the process proceeds to step S158 if YES, and proceeds to step S159 if NO. Then, in step S158, the low-quality service data and the low-quality service distribution range are acquired and stored in the service packet. In step S159, the service packet is transmitted to the broadcast address. In step S160, the service ID is incremented. Return to the main routine.
[0098]
FIG. 44 is a flowchart showing the service reception process (step S145) which is a subroutine of FIG.
[0099]
In step S161 of FIG. 44, the service ID and the destination address are acquired, and it is determined whether or not they are duplicated. If YES, the process proceeds to step S162, while if NO, the process returns to the original main routine. Next, the service data in the service packet received in step S162 is saved, and after registering the service transfer event in step S163, the process returns to the original main routine. Note that, in step S161 in FIG. 44, when the received service packet is sent again from another wireless station, the service packet is discarded without processing because there is a possibility that the service is equivalent and of low quality. In step S162, the received service data is stored for reproduction, and at this time, the service data having the smallest service distribution range is stored. Further, in step S163, a service transfer event is generated, and the service transfer process of FIG. 45 is performed.
[0100]
FIG. 45 is a flowchart showing the service transfer process (step S146) which is a subroutine of FIG.
[0101]
In step S171 of FIG. 45, the hop number I of the source address of the service packet is obtained from the position information estimation table, and in step S172, the service distribution range J is obtained from the service packet. Next, it is determined whether or not J <I + 1 in step S173. If YES, the process proceeds to a step S174, whereas if NO, the process proceeds to a step S175. In step S174, the service distribution range of the highest service data is deleted from the service packet. In step S175, the service packet is transmitted with the broadcast address, and the process returns to the main routine.
[0102]
In the branching process in step S173 of FIG. 45, by obtaining the number of hops of the service packet transmission source from the position information estimation table, it is possible to determine how many hops the service packet is currently in, and receive the information. By comparing with the service distribution range of the service packet, it is possible to check whether or not the service distribution range of the service packet is exceeded. Then, in the process of step S174, if the data exceeds each service range determined by the service sender, the data before that is meaningless only by enlarging the packet, so that only the packet necessary for the service distribution range is transferred. Running for
[0103]
In the service processing of FIGS. 42 to 45, the quality of service that can be transmitted can be changed according to the number of hops from the local station to the destination wireless station based on the position information estimation table.
[0104]
FIG. 46 is a front view showing an example of a routing table display tool displayed on the liquid crystal display 107b connected to the upper layer processing device 107 in FIG. 2, and FIG. 46 (a) is a front view showing the appearance of the display tool. FIG. 46B is an example when the area is divided and displayed in the display tool, and FIG. 46C is an example when the area is divided and displayed in the display tool. FIG. 46D shows an example in which the display tool displays an area divided into three parts. In FIG. 46, a white circle at the center indicates the position of the own radio station, while a black circle at the periphery indicates another radio station.
[0105]
The upper layer processing device 107 of FIG. 2 uses the information of the routing table of FIG. 31 created as described above to display, for example, as shown in FIG. The approximate distance (corresponding to the number of hops) of the wireless station is displayed. As described above, in order for the user of the own wireless station to approach the service provider who wants the service, how many hops the wireless station of the service provider has. Indicates that you are in the position of the number. That is, in the display tool of FIG. 46, the radio stations at the same hop number destination are displayed in a concentric display format as if they were located at positions having substantially the same radius.
[0106]
In the display tool of FIG. 46, when the display area is not divided, it is displayed as shown in FIG. 46 (b), when the display area is divided into two, it is displayed as shown in FIG. 46 (c), and when the display area is divided into three parts, It is displayed as shown at 46 (d). For example, when there are three adjacent wireless stations, one hop area is divided into three equal parts (= every 120 degrees), nodes are arranged, and the nodes of subsequent hops are assigned to the adjacent (next hop) nodes. By arranging them evenly within the azimuth, the display is made easier to see. When the display unit of a nearby wireless station is clicked with a mouse or instructed with a pen, the IP address or host name of the nearby wireless station is displayed in a pop-up manner as shown in FIG. Has become. 46 (b) to 46 (d) indicate the last three digits of the IP address.
[0107]
FIG. 47 is a front view showing an example of a topology display tool displayed on the liquid crystal display 107b connected to the upper layer processing device 107 in FIG. 2, and FIG. 47 (a) is a front view showing the appearance of the display tool. , (B) is a diagram in a wide area display of the display tool, (c) is a diagram in a standard display of the display tool, and (d) is a diagram in a detailed display of the display tool.
[0108]
The upper layer processing device 107 in FIG. 2 uses the information in the position information estimation table in FIG. 32 created as described above to display, on the liquid crystal display 107b, the area around its own wireless station as shown in FIG. 47, for example. Displays the location of the radio station (based on distance and azimuth information) and, as described above, how many radio stations of the service provider are in order for the user of the radio station to approach the service provider who desires the service. It indicates which azimuth position of the distance you are in. As a result, the user of the own radio station can easily approach the service provider who desires the service, thereby reducing the number of hops and receiving a higher quality service.
[0109]
In the display tool of FIG. 47, when it is desired to confirm the position of the peripheral wireless station in a wider area when the standard display in FIG. 47C is performed, an input device (not shown) connected to the upper layer processing device 107. By pressing the wide area key of FIG. 47, the wide area display of FIG. 47B is displayed, and the positions of a larger number of wireless stations can be seen. Further, when it is desired to confirm the position of a nearby detailed wireless station closer to the standard display in FIG. 47 (c), details of an input device (not shown) connected to the upper layer processing device 107. By pressing the key, the detailed display shown in FIG. 47D is displayed, and the detailed positions of the surrounding wireless stations can be seen. Similarly to the routing table display tool shown in FIG. 46, when the display unit of the peripheral wireless station is clicked with a mouse or instructed with a pen, as shown in FIG. The host name is displayed as a pop-up. Also, the numbers in circles of the peripheral wireless stations in FIGS. 47C and 47D indicate the last three digits of the IP address.
[0110]
In the above embodiment, the routing table display tool of FIG. 46 displays the IP address or host name and the number of hops of the peripheral radio station, and the topology display tool of FIG. 47 displays the position of the peripheral radio station (the distance and distance from the local station). (Representing an azimuth angle), the present invention may display at least one of these pieces of information.
[0111]
In the above embodiment, the variable beam antenna 101 has a sector beam pattern capable of selectively changing the sector-shaped main beam for each predetermined azimuth in a horizontal plane centered on the own station, and Although an exclusive sector pattern capable of forming a null point is provided so as to be selectively switchable, the present invention is not limited to this. The azimuth of the beam may be set digitally or analogously at any azimuth, and the exclusive sector pattern sets the azimuth forming the null point digitally or analogly at any azimuth. It may be possible.
[0112]
In the above embodiment, since the NLS table is created based on the AS table, it is not necessary to always save the AS table, and it may be a temporary storage table.
[0113]
In the above embodiment, a sector pattern having a predetermined azimuth angle width is used, but a radiation pattern having a predetermined radiation shape other than the sector shape may be used.
[0114]
In the above embodiment, the signal-to-interference-noise ratio (power ratio or signal ratio) is used as an evaluation value that is a reference when performing routing. However, the present invention is not limited to this, and the signal-to-noise ratio ( An evaluation value including a signal strength such as a power ratio or a signal ratio (here, noise includes all noises), signal power, and signal strength may be used.
[0115]
In the above embodiments, wireless communication is performed by packet communication between the wireless stations. However, the present invention is not limited to this, and wireless communication may be performed by another switching method such as circuit switching.
[0116]
【Example】
The inventors have realized a firefly net system according to the present embodiment by computer simulation, and have used the same to evaluate angled topology information, which is a function of the firefly net, as follows. The following table shows the simulation conditions at that time.
[0117]
[Table 1]
―――――――――――――――――――――――――――――――――
(1) 36 nodes are uniform in an area of 1000m x 1000m
They are arranged randomly.
(2) Fluctuating factors of the radio wave environment are not considered.
(3) No movement of the radio station.
(4) The radio wave reach is about 350 m.
―――――――――――――――――――――――――――――――――
[0118]
FIG. 48 is a graph showing a computer simulation result of the firefly net according to the present embodiment, showing the average error of the azimuth angle and the average error of the distance with respect to the number of hops. As is apparent from FIG. 48, even when the number of hops increases, the error in the azimuth angle hardly changes and stays at about 5.6 degrees. Although the error decreases after 3 hops, the route with the minimum number of hops is selected in the routing protocol used this time. It is thought that the angle error hardly changed, and the error of the distance did not affect much, thereby reducing the error of the angle. Although the distance slightly increases with the number of hops, it is considered that the distance can be sufficiently used as a guide when approaching.
[0119]
【The invention's effect】
As described above in detail, according to the wireless network control method or control apparatus of the present invention, the first of the received signal power values for each predetermined azimuth to each adjacent wireless station within the service area of one wireless station is provided. Is transmitted and received between the wireless stations, and based on the received first information table, a second information table of the azimuth angle and the received signal power value of each adjacent wireless station is transmitted from the own station to the corresponding information table. A third information table of the azimuth angle and the received signal power value of each adjacent wireless station that is a wireless station within the service area of the wireless station is generated and stored in a storage device, and the second and third information are stored Based on the table, the number of hops to the adjacent wireless station and the destination wireless station with respect to the destination wireless station is calculated based on a predetermined routing criterion, and stored in the storage device as a fourth information table. 4 based on the information table Calculating a distance, an azimuth angle, and a hop number from the own station to each wireless station in the wireless network, storing the calculated information in a storage device as a fifth information table, and storing each wireless station included in the fifth information table. And displaying at least one of a distance, an azimuth, and a hop count. Here, the position indicating the distance and the azimuth to each wireless station is displayed in a topology display format centering on the own station, or the number of hops to each wireless station is displayed in a concentric circle centering on the own station. Display in format. Therefore, for example, it is possible to change the service quality on the information receiving side, and if the content is of interest, the user can get closer to the service provider's radio station to receive a higher quality service. Thereby, the demand of the user can be satisfied.
[0120]
Further, in the wireless network control method, the quality of service that can be transmitted is changed according to the number of hops from the own station to the destination wireless station based on the fifth information table. Therefore, since the quality of service that can be transmitted can be automatically changed according to the number of hops, it is possible to satisfy the needs of the user as described above and to perform flexible operation in the wireless communication network. Thus, it is also possible to control traffic according to the data transmission amount. Further, by moving away from a wireless station that provides information that the user is not interested in, it is possible to prevent unnecessary data transmission and efficiently operate the wireless network.
[Brief description of the drawings]
FIG. 1 is a plan view of a plurality of wireless stations 1-1 to 1-9 constituting an ad hoc wireless network according to an embodiment of the present invention.
FIG. 2 is a block diagram showing an internal configuration of each wireless station 1 of FIG.
FIG. 3 is a diagram showing an example of a sector beam pattern of the variable beam antenna 101 of FIG.
FIG. 4 is a diagram showing an example of an azimuth angle versus SINR table (AS table) stored in a database memory 154 of FIG. 2;
FIG. 5 is a diagram illustrating an example of an adjacent link state table (NLS table) stored in a database memory 154 of FIG. 2;
FIG. 6 is a diagram illustrating an example of a communicating table (OC table) stored in a database memory 154 of FIG. 2;
FIG. 7 is a diagram illustrating a frame format of an RQ (Request) signal used in a MAC layer of the ad hoc wireless network of FIG. 1;
8 is a diagram showing a frame format of a RE (Reply) signal used in a MAC layer of the ad hoc wireless network of FIG. 1;
FIG. 9 is a diagram illustrating a frame format of an RTS (Request-to-Send) signal used in a MAC layer of the ad hoc wireless network of FIG. 1;
FIG. 10 is a diagram showing a frame format of a CTS (Clear-to-Send) signal used in the MAC layer of the ad hoc wireless network of FIG. 1;
FIG. 11 is a diagram showing a frame format of a DATA signal used in a MAC layer of the ad hoc wireless network of FIG. 1;
12 is a diagram illustrating a frame format of an ACK (Acknowledgment) signal used in a MAC layer of the ad hoc wireless network of FIG. 1;
FIG. 13 is a plan view showing an arrangement of each wireless station and an antenna radiation pattern when it is known that another communication has already been performed in the ad hoc wireless network of FIG. 1;
14 is a diagram illustrating an antenna radiation pattern in each state for each signal used in the ad hoc wireless network of FIG. 1;
FIG. 15 is a flowchart showing a first part of a packet transmission / reception control process executed in the MAC layer by the management control unit 151 in the traffic monitor unit 105 in FIG. 2;
FIG. 16 is a flowchart showing a second part of the packet transmission / reception control process.
FIG. 17 is a flowchart showing a third part of the packet transmission / reception control process.
FIG. 18 is a flowchart showing a fourth part of the packet transmission / reception control process.
FIG. 19 is a flowchart showing a fifth part of the packet transmission / reception control process.
FIG. 20 is a flowchart showing a sixth part of the packet transmission / reception control process.
FIG. 21 is a flowchart showing a seventh part of the packet transmission / reception control process.
FIG. 22 is a flowchart showing an eighth part of the packet transmission / reception control process.
FIG. 23 is a flowchart showing a ninth part of the packet transmission / reception control process.
24 is a flowchart showing an exclusive sector pattern release process executed by the management controller 151 in the traffic monitor unit 105 in FIG.
25 is a diagram illustrating an example of an azimuth-versus-received-signal power value table used in the MAC layer by the upper layer processing device 107 of FIG. 2 and stored in a table memory 107a connected to the upper layer processing device 107.
26 is a diagram showing a format of a hello packet used in the MAC layer of the wireless ad hoc network of FIG. 1;
FIG. 27 is a diagram illustrating a process of calculating a distance Lc between the own wireless station and the adjacent wireless station, which is performed in the MAC layer by the upper layer processing device 107 in FIG. 2;
FIG. 28 is an image diagram of service provision in the present embodiment.
29 is a diagram illustrating an example of an adjacent wireless station table used in the network layer by the upper layer processing device 107 of FIG. 2 and stored in the table memory 107a connected to the upper layer processing device 107.
30 is a diagram illustrating an example of a topology table used in the network layer by the upper layer processing device 107 of FIG. 2 and stored in a table memory 107a connected to the upper layer processing device 107;
31 is a diagram illustrating an example of a routing table used in the network layer by the upper layer processing device 107 of FIG. 2 and stored in a table memory 107a connected to the upper layer processing device 107.
32 is a diagram showing an example of a position information estimation table used in the network layer by the upper layer processing device 107 of FIG. 2 and stored in the table memory 107a connected to the upper layer processing device 107.
FIG. 33 is a flowchart showing azimuth-attached topology information distribution processing executed in the MAC layer by the upper layer processing device 107 of FIG. 2;
FIG. 34 is a flowchart showing a reception process (step S103) which is a subroutine of FIG.
FIG. 35 is a flowchart showing a first part of a process of estimating position information from a route (step S115), which is a subroutine of FIG. 34;
36 is a flowchart showing a second part of the process of estimating position information from a route (step S115), which is a subroutine of FIG. 34.
FIG. 37 is a diagram illustrating an example of topology information distribution processing executed in the network layer by the upper layer processing device 107 in FIG. 2, where (a) illustrates the distribution of topology information from the wireless station 1-K; b) shows a topology table in the wireless stations 1-K and 1-L.
38 is a diagram illustrating an example of topology information distribution processing executed in the network layer by the upper layer processing device 107 in FIG. 2, where (a) illustrates reception of topology information at the wireless station 1-L; b) shows a topology table in the wireless stations 1-K and 1-L.
39 is a diagram illustrating an example of a calculation process of a distance and an azimuth angle other than the adjacent wireless station, which is executed in the network layer by the upper layer processing device 107 in FIG. 2, and (a) illustrates an arrangement relationship of each wireless station; , (B) shows the topology table of the wireless station 1-L.
40 is a diagram illustrating an example of a distance calculation process executed in the network layer by the upper layer processing device 107 in FIG. 2; (a) illustrates an arrangement relationship of each wireless station; 4 shows an L topology table.
FIG. 41 is a diagram showing a format of a service packet used in an application layer in the upper layer processing device 107 of FIG. 2;
FIG. 42 is a flowchart showing service processing executed in the application layer by the upper layer processing device 107 of FIG. 2;
FIG. 43 is a flowchart showing a service transmission process (step S144) which is a subroutine of FIG.
FIG. 44 is a flowchart showing a service reception process (step S145) which is a subroutine of FIG.
FIG. 45 is a flowchart showing a service transfer process (step S146) which is a subroutine of FIG.
46 is a front view showing an example of a routing table display tool displayed on the liquid crystal display 107b connected to the upper layer processing device 107 in FIG. 2, and (a) is a front view showing the appearance of the display tool; (B) is an example when the area is displayed in the display tool without dividing the area, (c) is an example when the area is divided into two in the display tool, and (d) is an example. This is an example when the display tool displays an area divided into three parts.
47 is a front view showing an example of a topology display tool displayed on the liquid crystal display 107b connected to the upper layer processing device 107 in FIG. 2, and FIG. 47 (a) is a front view showing the appearance of the display tool; Yes, (b) is a diagram in a wide area display of the display tool, (c) is a diagram in a standard display of the display tool, and (d) is a diagram in a detailed display of the display tool.
FIG. 48 is a graph showing a result of computer simulation in the wireless ad hoc network of FIG. 1, showing an average error of an azimuth angle and an average error of a distance with respect to the number of hops.
[Explanation of symbols]
1,1-1 to 1-9 ... wireless stations,
101 ... variable beam antenna,
102: circulator,
103 ... pointing control unit,
104: Packet transmitting / receiving unit
105: traffic monitor unit
106 ... line control unit,
107: Upper layer processing device,
107a: table memory,
107b: liquid crystal display,
130 ... Packet receiving unit,
131 ... high frequency receiver,
132 demodulator,
133: reception buffer memory,
140 ... packet transmitting unit,
141: transmission timing control unit,
142 transmission buffer memory,
143: modulator,
144: high frequency transmitter,
151 management and control unit
152 ... search engine,
153 ... Update engine,
154: database memory,
155: clock circuit,
160 ... Spreading code generator.

Claims (8)

A method for controlling a wireless network comprising a plurality of wireless stations and performing wireless communication between the wireless stations,
Transmitting and receiving between the wireless stations a first information table of received signal power values for each predetermined azimuth to each adjacent wireless station within a service area of one wireless station;
Based on the received first information table, a second information table of the azimuth angle and the received signal power value of each adjacent wireless station from the own station and each of the wireless stations within the service area of each adjacent wireless station. Generating a third information table of the azimuth of the adjacent wireless station and the received signal power value and storing the third information table in a storage device;
A step of calculating the number of hops between the adjacent wireless station and the destination wireless station with respect to the destination wireless station based on the predetermined routing criteria based on the second and third information tables and storing the calculated number of hops in the storage device as a fourth information table When,
Based on the second, third, and fourth information tables, the distance, azimuth, and hop number from the own station to each wireless station in the wireless network are calculated and stored in the storage device as a fifth information table. Steps to
Displaying at least one of a distance, an azimuth, and a hop number to each wireless station included in the fifth information table. 2. The method according to claim 1, wherein the displaying step displays the position indicating the distance and the azimuth to each wireless station in a topology display format centering on the own station. 3. The wireless network control method according to claim 1, wherein the displaying step displays the number of hops to each wireless station in a display form of a concentric circle centered on the own station. The method according to any one of claims 1 to 3, further comprising the step of changing the quality of service that can be transmitted according to the number of hops from the own station to the destination wireless station based on the fifth information table. A method for controlling a wireless network according to any one of the preceding claims. A wireless network control device comprising a plurality of wireless stations and performing wireless communication between the wireless stations,
Transmitting and receiving a first information table of received signal power values for each predetermined azimuth to each adjacent wireless station in a service area of one wireless station between the wireless stations;
Based on the received first information table, a second information table of the azimuth angle and the received signal power value of each adjacent wireless station from the own station and each of the wireless stations within the service area of each adjacent wireless station. A third information table of the azimuth of the adjacent wireless station and the received signal power value is generated and stored in the storage device,
Based on the second and third information tables, the number of hops to the adjacent wireless station and the destination wireless station with respect to the destination wireless station is calculated based on a predetermined routing criterion, and stored in the storage device as a fourth information table;
Based on the second, third, and fourth information tables, the distance, azimuth, and hop number from the own station to each wireless station in the wireless network are calculated and stored in the storage device as a fifth information table. And
A control device for a wireless network, comprising: control means for displaying at least one of a distance, an azimuth, and a hop number to each wireless station included in the fifth information table. The wireless network control device according to claim 5, wherein the control means displays a position indicating a distance and an azimuth to each wireless station in a topology display format centering on the own station. 7. The control device for a wireless network according to claim 5, wherein the control means displays the number of hops to each wireless station in a display form of a concentric circle centering on the own station. 8. The system according to claim 5, wherein the control unit further changes the quality of service that can be transmitted according to the number of hops from the own station to the destination wireless station based on the fifth information table. The control device for a wireless network according to any one of the above.

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