JP3886464B2

JP3886464B2 - Method and apparatus for measuring azimuth angle of wireless station in wireless network

Info

Publication number: JP3886464B2
Application number: JP2003053965A
Authority: JP
Inventors: 正浩渡辺; 信介田中
Original assignee: ATR Advanced Telecommunications Research Institute International
Current assignee: ATR Advanced Telecommunications Research Institute International
Priority date: 2003-02-28
Filing date: 2003-02-28
Publication date: 2007-02-28
Anticipated expiration: 2023-02-28
Also published as: JP2004266523A

Description

【０００１】
【発明の属する技術分野】
本発明は、複数の無線局を備えた、例えば無線ＬＡＮなどの無線アドホックネットワークにおいて、無線通信を行う無線ネットワークにおける無線局の方位角を測定するための方法及び装置に関する。
【０００２】
【従来の技術】
無線アドホックネットワークは、無線端末間の無線通信を基地局等のインフラストラクチャを用いることなく、無線端末間で直接に通信が出来ることが特徴である。実際の無線通信環境では、無線端末が自由に移動するダイナミックな変動があり、無線端末自身がルータ等の機能を有して自律的に適応し、各無線端末間では分散的に協調する必要がある。
【０００３】
また、いわゆる、電波が届かないために、直接に通信が出来ない端末間の場合には、他の端末を中継局として、目的端末まで、マルチホップ通信を行うことにより、通信を可能としている。この中継局の選択方法が、無線アドホックネットワークにおけるルーティングである。従来技術の無指向性アンテナを前提としたルート探索パケットをフラッディングする方法では、ネットワークへの負荷が高く性能が低下する。そこで、定期的に、設定した角度単位で指向性ビームをステアリングし、各端末の受信電界強度を測定して、所定の角度毎の各無線局に対する信号対干渉雑音電力比（ＳＩＮＲ）情報を含むＡＳテーブル（Angle-SINR-Table）を作成し、このＡＳテーブル情報に基づいて、電波環境の良い中継無線端末を探索して、指向性ビームで通信することにより、同一チャネル間干渉を抑圧してネットワークの性能を向上する方法が特許文献１において提案されている。また、振幅モノパルスのレーダを用いた測角処理が非特許文献１において開示されている。
【０００４】
【特許文献１】
特開２００１−２４４９８３号公報。
【非特許文献１】
渡辺正浩ほか，“レーダ測角処理の一例”，２０００年電子情報通信学会基礎・境界ソサイエティ大会講演論文集，電子情報通信学会発行，Ａ−１７−２０，２０００年９月。
【非特許文献２】
大平孝，”適応アンテナの民生化にむけて”，平成１１年電気関係学会関西支部連合大会シンポジウム，「最近のマイクロ波・ミリ波技術」，電気学会発行，Ｓ８−１，ｐｐ．Ｓ４１，１９９９年１１月１４日。
【非特許文献３】
大平孝ほか，”マイクロ波信号処理によるアダプティブビーム形成と電子制御導波器（ＥＳＰＡＲ）アンテナの提案”，電子情報通信学会研究技術報告，電子情報通信学会発行，ＡＰ９９−６１，ＳＡＴ９９−６１，ｐｐ．９−１４，１９９９年７月。
【非特許文献４】田野哲ほか，”Ｍ−ＣＭＡ：マイクロ波信号処理による適応ビーム形成のためのデジタル信号処理アルゴリズム”，電子情報通信学会研究技術報告，電子情報通信学会発行，ＡＰ９９−６２，ＳＡＴ９９−６２，ｐｐ．１５−２２，１９９９年７月。
【０００５】
【発明が解決しようとする課題】
しかしながら、特許文献１に記載された方位角測定処理では、例えば３０度毎の無線局の方向しか把握することができず、詳細な無線局の方位角を測定することができなかった。また、非特許文献１に記載の測角処理では、レーダを用いてより精度の高い方向の方位角を測定することができるが、例えば１台の自動車から他の自動車への方向しか測定することができず、複数の無線局を備えた無線アドホックネットワークにおいて各無線局の方位角を測定することはできないという問題点があった。
【０００６】
また、特許文献１に記載された方位角測定処理では、全方位を走査するために、ＳＩＮＲの測定を要求するＲＱ信号を３０度毎で１２回送信した後、ＲＱ信号を受信した受信局からその無線局の数分だけその応答信号であるＲＥ信号を送信側無線局で受信する必要があり、本来の通信を行う前のオーバーヘッドが長くなるという問題点があった。
【０００７】
本発明の目的は以上の問題点を解決し、複数の無線局を備えた無線ネットワークにおいて、１つの無線局から他の複数の無線局への方向を、従来技術に比較して高い精度で測定することができ、しかもオーバーヘッドを低減できる無線ネットワークにおける無線局の方位角測定方法及び装置を提供することにある。
【０００８】
【課題を解決するための手段】
第１の発明に係る無線ネットワークにおける無線局の方位角測定方法は、複数の無線局を備え、各無線局間で無線通信を行う無線ネットワークにおける無線局の方位角測定方法において、
上記複数の無線局のうちのサービスエリア内の各無線局に対する、所定の方位角毎の、受信電界強度、受信信号対干渉雑音比又は搬送波対干渉雑音比である信号測定値を予め測定して信号測定値テーブルとして記憶装置に記憶する第１のステップと、
上記各無線局からの送信信号を、上記信号測定値テーブルにおける最大値の信号測定値を有する方位角の主ビームのセクタパターンを含む互いに隣接する少なくとも２つのセクタパターンを用いてそれぞれ受信電界強度を測定し、上記測定した各受信電界強度に基づいて、モノパルス測角処理を用いて、予め測定された上記２つのセクタパターンの差パターンをその和パターンで除算した商パターンを上記２つのセクタパターンの主ビームの方位角間で直線近似して最大の受信電界強度を有する、上記送信信号を送信した無線局の方位角を計算する第２のステップとを含むことを特徴とする。
【０００９】
上記無線ネットワークにおける無線局の方位角測定方法において、上記第２のステップは、上記各無線局からの送信信号を、上記信号測定値テーブルにおける最大値の信号測定値を有する方位角の主ビームのセクタパターンを含む互いに隣接する少なくとも３つのセクタパターンを用いてそれぞれ受信電界強度を測定し、互いに隣接する各２つのセクタパターンで測定した各受信電界強度に基づいて、モノパルス測角処理を用いて、予め測定された上記各２つのセクタパターンの差パターンをその和パターンで除算した商パターンを上記各２つのセクタパターンの主ビームの方位角間で直線近似して最大の受信電界強度を有する各方位角を計算し、計算された複数の方位角の平均値を、上記送信信号を送信した無線局の方位角として推定することを特徴とする。
【００１０】
第２の発明に係る無線ネットワークにおける無線局の方位角測定方法は、複数の無線局を備え、各無線局間で無線通信を行う無線ネットワークにおける無線局の方位角測定方法において、
上記複数の無線局のうちのサービスエリア内の各無線局からの送信信号を、所定の方位角毎の互いに隣接する少なくとも２つのセクタパターンを用いてそれぞれ受信電界強度を測定し、上記測定した各受信電界強度に基づいて、モノパルス測角処理を用いて、予め測定された上記２つのセクタパターンの差パターンをその和パターンで除算した商パターンを上記２つのセクタパターンの主ビームの方位角間で直線近似して最大の受信電界強度を有する、上記送信信号を送信した無線局の方位角を計算する第１のステップを含むことを特徴とする。
【００１１】
上記無線ネットワークにおける無線局の方位角測定方法において、上記第１のステップの処理を実行した後、上記各無線局からの送信信号を、上記第１のステップで計算された方位角に最も近接する方位角の主ビームのセクタパターンを含む互いに隣接する少なくとも２つのセクタパターンを用いてそれぞれ受信電界強度を測定し、上記測定した各受信電界強度に基づいて、モノパルス測角処理を用いて、予め測定された上記２つのセクタパターンの差パターンをその和パターンで除算した商パターンを上記２つのセクタパターンの主ビームの方位角間で直線近似して最大の受信電界強度を有する、上記送信信号を送信した無線局の方位角を計算する第２のステップをさらに含むことを特徴とする。
【００１２】
また、上記無線ネットワークにおける無線局の方位角測定方法において、上記第２のステップは、上記各無線局からの送信信号を、上記信号測定値テーブルにおける最大値の信号測定値を有する方位角の主ビームのセクタパターンを含む互いに隣接する少なくとも３つのセクタパターンを用いてそれぞれ受信電界強度を測定し、互いに隣接する各２つのセクタパターンで測定した各受信電界強度に基づいて、モノパルス測角処理を用いて、予め測定された上記各２つのセクタパターンの差パターンをその和パターンで除算した商パターンを上記各２つのセクタパターンの主ビームの方位角間で直線近似して最大の受信電界強度を有する各方位角を計算し、計算された複数の方位角の平均値を、上記送信信号を送信した無線局の方位角として推定することを特徴とする。
【００１３】
第３の発明に係る無線ネットワークにおける無線局の方位角測定装置は、複数の無線局を備え、各無線局間で無線通信を行う無線ネットワークにおける無線局の方位角測定装置において、
上記複数の無線局のうちのサービスエリア内の各無線局に対する、所定の方位角毎の、受信電界強度、受信信号対干渉雑音比又は搬送波対干渉雑音比である信号測定値を予め測定して信号測定値テーブルとして記憶装置に記憶する第１の制御手段と、
上記各無線局からの送信信号を、上記信号測定値テーブルにおける最大値の信号測定値を有する方位角の主ビームのセクタパターンを含む互いに隣接する少なくとも２つのセクタパターンを用いてそれぞれ受信電界強度を測定し、上記測定した各受信電界強度に基づいて、モノパルス測角処理を用いて、予め測定された上記２つのセクタパターンの差パターンをその和パターンで除算した商パターンを上記２つのセクタパターンの主ビームの方位角間で直線近似して最大の受信電界強度を有する、上記送信信号を送信した無線局の方位角を計算する第２の制御手段とを備えたことを特徴とする。
【００１４】
上記無線ネットワークにおける無線局の方位角測定装置において、上記第２の制御手段は、上記各無線局からの送信信号を、上記信号測定値テーブルにおける最大値の信号測定値を有する方位角の主ビームのセクタパターンを含む互いに隣接する少なくとも３つのセクタパターンを用いてそれぞれ受信電界強度を測定し、互いに隣接する各２つのセクタパターンで測定した各受信電界強度に基づいて、モノパルス測角処理を用いて、予め測定された上記各２つのセクタパターンの差パターンをその和パターンで除算した商パターンを上記各２つのセクタパターンの主ビームの方位角間で直線近似して最大の受信電界強度を有する各方位角を計算し、計算された複数の方位角の平均値を、上記送信信号を送信した無線局の方位角として推定することを特徴とする。
【００１５】
第４の発明に係る無線ネットワークにおける無線局の方向測定装置は、複数の無線局を備え、各無線局間で無線通信を行う無線ネットワークにおける無線局の方位角測定装置において、
上記複数の無線局のうちのサービスエリア内の各無線局からの送信信号を、所定の方位角毎の互いに隣接する少なくとも２つのセクタパターンを用いてそれぞれ受信電界強度を測定し、上記測定した各受信電界強度に基づいて、モノパルス測角処理を用いて、予め測定された上記２つのセクタパターンの差パターンをその和パターンで除算した商パターンを上記２つのセクタパターンの主ビームの方位角間で直線近似して最大の受信電界強度を有する、上記送信信号を送信した無線局の方位角を計算する第１の制御手段を備えたことを特徴とする。
【００１６】
上記無線ネットワークにおける無線局の方位角測定装置において、上記第１の制御手段の処理を実行した後、上記各無線局からの送信信号を、上記第１の制御手段で計算された方位角に最も近接する方位角の主ビームのセクタパターンを含む互いに隣接する少なくとも２つのセクタパターンを用いてそれぞれ受信電界強度を測定し、上記測定した各受信電界強度に基づいて、モノパルス測角処理を用いて、予め測定された上記２つのセクタパターンの差パターンをその和パターンで除算した商パターンを上記２つのセクタパターンの主ビームの方位角間で直線近似して最大の受信電界強度を有する、上記送信信号を送信した無線局の方位角を計算する第２の制御手段をさらに備えたことを特徴とする。
【００１７】
また、上記無線ネットワークにおける無線局の方位角測定装置において、上記第２の制御手段は、上記各無線局からの送信信号を、上記信号測定値テーブルにおける最大値の信号測定値を有する方位角の主ビームのセクタパターンを含む互いに隣接する少なくとも３つのセクタパターンを用いてそれぞれ受信電界強度を測定し、互いに隣接する各２つのセクタパターンで測定した各受信電界強度に基づいて、モノパルス測角処理を用いて、予め測定された上記各２つのセクタパターンの差パターンをその和パターンで除算した商パターンを上記各２つのセクタパターンの主ビームの方位角間で直線近似して最大の受信電界強度を有する各方位角を計算し、計算された複数の方位角の平均値を、上記送信信号を送信した無線局の方位角として推定することを特徴とする。
【００１８】
【発明の実施の形態】
以下、図面を参照して本発明に係る実施形態について説明する。
【００１９】
図１は、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の構成を示す複数の無線局１−１乃至１−９（総称して、符号１を付す。）の平面配置図であり、図２は、図１の各無線局１の構成を示すブロック図である。
【００２０】
この実施形態の無線通信システムは、例えば無線ＬＡＮなどのアドホック無線ネットワークのパケット通信システムに適用するものであって、各無線局１は、図１に示すように、主ビームの方向を変更可能な可変ビームアンテナ１０１を備え、自局を中心とした水平面内の所定の方位角毎のサービスエリア内の無線局１に対するＳＩＮＲを予め測定し、そのテーブル（Angle SINR Table；以下、ＡＳテーブルという。）に基づいてパケットのルーチングを行うとともに、当該ＡＳテーブルに基づいてモノパルス測角処理を用いた、図８のフローチャートに示す無線局方位角測定処理を実行することにより、他の無線局の方位角を従来技術に比較して高精度で測定することを特徴としている。
【００２１】
この実施形態の無線通信システムでは、図１に示すように、複数の無線局１が平面的に散在して存在し、各無線局１はそれぞれ、可変ビームアンテナ１０１の利得や送信電力、受信感度などのパラメータで決定される所定のサービスエリアを有し、このサービスエリア内でパケット通信を行うことができ、サービスエリア外の無線局１とパケット通信を行うときは、サービスエリア内の無線局１を中継局として用いてパケットデータを中継することにより、所望の宛先無線局１にパケットデータを伝送する。すなわち、各無線局１は、パケットのルーチングを行うルータ装置を備え、発信端末、中継局、又は宛先端末として動作する。
【００２２】
次いで、図２を参照して、各無線局１の装置構成について説明する。図２において、無線局１は、可変ビームアンテナ１０１と、その指向性を制御するための指向制御部１０３と、サーキュレータ１０２と、データパケット送信部１４０及びデータパケット受信部１３０を有するデータパケット送受信部１０４と、トラヒックモニタ部１０５と、回線制御部１０６と、上位レイヤ処理部１０７とを備える。
【００２３】
送受信すべきデータを処理する上位レイヤ処理装置１０７によって発生されたパケット形式の通信用送信信号データは、送信バッファメモリ１４２を介して変調器１４３に入力され、変調器１４３は、所定の無線周波数の搬送波信号を、拡散符号発生器１６０でＣＤＭＡ方式で発生された所定の通信チャネル用拡散符号を用いて、入力された通信用送信信号データに従ってスペクトル拡散変調して、変調後の送信信号を高周波送信機１４４に出力する。高周波送信機１４４は入力された送信信号に対して増幅などの処理を実行した後、サーキュレータ１０２を介して可変ビームアンテナ１０１から他の無線局１に向けて送信する。一方、可変ビームアンテナ１０１で受信されたパケット形式の通信チャネル用受信信号は、サーキュレータ１０２を介して高周波受信機１３１に入力され、高周波受信機１３１は入力された受信信号に対して低雑音増幅などの処理を実行した後、復調器１３２に出力する。復調器１３２は、入力される受信信号を、拡散符号発生器１６０でＣＤＭＡ方式で発生された通信チャネル用拡散符号を用いて、スペクトル逆拡散により復調して、復調後の受信信号データを上位レイヤ処理装置１０７に出力するとともに、トラヒックモニタのためにトラヒックモニタ部１０５に出力する。
【００２４】
本実施形態においては、指向性アンテナである可変ビームアンテナ１０１は、複数のアンテナ素子とその指向性を制御する制御部１０３からなり、例えば、所定のビーム幅を有し０度から３３０度までの３０度毎に主ビーム方向を有する１２個のセクタパターン及びオムニパターン（無指向性パターン）を備え、上記各セクタパターンの主ビームの方向を、例えば３０度の所定の走査間隔で電気的な制御により変更可能であるアンテナである。なお、可変ビームアンテナ１０１については、例えば、公知のフェーズドアレーアンテナ装置であってもよいし、もしくは、非特許文献２乃至４などに開示された電子制御導波器アレーアンテナであってもよい。また、セクタパターンとは、例えば、図４に示すように、所定の主ビーム幅を有する扇型形状の放射パターンをいう。
【００２５】
トラヒックモニタ部１０５は、検索エンジン１５２と、更新エンジン１５３と、データベースメモリ１５４とを備え、図８の無線局方位角測定処理を実行するとともに、無線局１が他の無線局１とのパケット通信において使用すべき通信チャネルを決定して、決定した通信チャネルに対応する拡散符号の指定データを回線制御部１０６を介して拡散符号発生器１６０に送ることにより、拡散符号発生器１６０が当該指定データに対応する拡散符号を発生するように制御するとともに、決定した通信チャネルに対応するタイムスロットの指定データを回線制御部１０６を介して送信タイミング制御部１４１に送ることにより、送信タイミング制御部１４１が送信バッファメモリ１４２による通信チャネル用送信信号データの書き込み及び読み出しを制御することにより通信チャネル用送信信号が対応するタイムスロットで送信されるように制御する。
【００２６】
トラヒックモニタ部１０５の検索エンジン１５２は、管理制御部１５１の制御によりデータベースメモリ１５４内のデータを検索して検索したデータを管理制御部１５１に返信する。また、更新エンジン１５３は、管理制御部１５１の制御によりデータベースメモリ１５４内のデータを更新する。さらに、データベースメモリ１５４には、自局ＡＳテーブル、他局ＡＳテーブル、ルーチングテーブル及び無線局テーブルを記憶する。
【００２７】
データベースメモリ１５４に予め格納される自局ＡＳテーブルは、図３にその一例を示すように、自局を中心とした水平面内の所定の方位角毎のサービスエリア内の各無線局１に対するＳＩＮＲを予め測定してテーブル形式で記憶するとともに、図８の無線局方位角測定処理を実行することにより測定された他の各無線局１に対する詳細方位角を記憶している。ここで、ＳＩＮＲを測定するためには、他の各無線局１と所定のトレーニングパターンのデータパケットを送受信することによりビット誤り率（ＢＥＲ）を測定し、無線通信の変復調方式で決定されるＳＩＮＲに対するＢＥＲ特性のグラフを用いて、ＳＩＮＲに換算する。例えば、ＣＤＭＡ方式を用いるときは、ＳＩＮＲに対するＢＥＲ特性のグラフを用いて換算することができ、例えば、ＱＰＳＫ差動検波方式を用いるときは、搬送波電力対雑音電力比（ＣＮＲ）に対するＢＥＲ特性のグラフを用いて換算することができる。すなわち、搬送波電力対干渉雑音電力比（以下、ＣＩＮＲという。）を用いるか、もしくはＳＩＮＲを用いるかは、無線システムで使用する変復調方式に依存する。本発明では、同一チャンネル干渉雑音に関する測定値であればよい。また、これに代えて、受信電界強度であってもよい。
【００２８】
また、データベースメモリ１５４に格納された他局ＡＳテーブルは、上記自局ＡＳテーブルと同様の形式を有する、他の無線局１におけるＡＳテーブルであって、所定のパケットの送受信制御処理により他局より取得してデータベースメモリ１５４に格納する。さらに、ルーチングテーブルは、当該アドホック無線ネットワークにおいて存在する各無線局毎に対して、１ホップ目の無線局のＩＤと、ホップ数と、更新時刻を、過去に送受信したデータパケットのデータに基づいて格納する。またさらに、無線局テーブルは、当該アドホック無線ネットワークにおいて存在する無線局のＩＤを、過去に送受信したデータパケットのデータに基づいて格納する。
【００２９】
次いで、本実施形態に係る無線局方位角測定処理において用いるモノパルス処理について以下に説明する。なお、本実施形態で用いる可変ビームアンテナ１０１は、例えば主ビームの方向が０度方向であるとき、その主ビームを有するセクタパターンを中心セクタパターンといい、当該中心セクタパターンの右側の３０度方向のセクタパターンを右セクタパターンといい、当該中心セクタパターンの左の−３０度方向のセクタパターンを左セクタパターンという。これらのセクタパターンのデータは予め公知の方法で測定されてデータベースメモリ１５４に格納されているものとする。
【００３０】
このモノパルス処理は、右セクタパターンと中心セクタパターン、もしくは中心セクタパターンと左セクタパターンの走査した各２方向の指向性を有するセクタパターンを用いて他の無線局からの電波を受信して電界強度を測定し、これら２方向のセクタパターンの和及び差に基づいた近似直線から当該他の無線局の方向の角度θと、標準偏差σを計算するものである（例えば、非特許文献１参照。）。
【００３１】
例えば、図４に示す、互いに隣接する左セクタパターンと中心セクタパターンとに基づいてモノパルス測角処理を行うとき（中心走査角θ_Ｃ−左側走査角θ_Ｌ＝３０度）、それらの和パターンＳ（θ）及び差パターンＤ（θ）と、和パターンＳ（θ）の３ｄＢ幅θｓと、差パターンＤ（θ）を和パターンＳ（θ）で除算した商Ｄ（θ）／Ｓ（θ）のパターン（以下、商パターンという。）とを図５及び図６に示すように予め計算しておき、図６の中心走査角θ_Ｃと左側走査角θ_Ｌとの間の商パターンを直線で近似し、その直線の傾きｋを計算してデータベースメモリ１５４に格納しておく。次いで、中心セクタパターンで測定した受信電界強度Ｐ１と、左セクタパターンで測定した受信電界強度Ｐ２とを測定して、以下のようにして測定すべき他の無線局の方向の角度θを計算できる。なお、互いに隣接する中心セクタパターンと右セクタパターンとに基づいてモノパルス測角処理を行うときも同様である。
【００３２】
まず、２つの受信電界強度Ｐ１，Ｐ２と商Ｄ（θ）／Ｓ（θ）との関係は次式で表される。
【００３３】
【数１】
（Ｐ１−Ｐ２）／（Ｐ１＋Ｐ２）
＝Ｄ（θ）／Ｓ（θ）
【００３４】
一方、図６から明らかなように、次式が成立する。
【００３５】
【数２】
θ＝θｓ・（Ｄ（θ）／Ｓ（θ））／ｋ
【００３６】
上記数１を上記数２に代入すると、次式を得る。
【００３７】
【数３】
θ＝θｓ・｛（Ｐ１−Ｐ２）／（Ｐ１＋Ｐ２）｝／ｋ
【００３８】
従って、互いに隣接する２つのセクタパターンを用いて測定された受信電界強度Ｐ１，Ｐ２に基づいて、上記数３を用いて、他の無線局の方向の角度θを計算できる。さらに、複数ｎ回測定したときの標準偏差σの値は、次式を用いて計算できる。
【００３９】
【数４】
σ＝θｓ／ｋ√（（Ａ_ＳＮＲ）・ｎ）
【００４０】
ここで、Ａ_ＳＮＲは、２つの受信電界強度Ｐ１，Ｐ２のＳＩＮＲの平均値である。例えば、モノパルス処理としての観測回数ｎ＝２のときは、例えば、左セクタパターンと中心セクタパターンとを用いるモノパルス測角処理と、中心セクタパターンと右セクタパターンとを用いるモノパルス測角処理とを実行して、測定値を平均化する方法を用いることができる。
【００４１】
図７は本実施形態に係る無線局方位角測定処理の通信手順を示すシーケンスチャートであり、図８は本実施形態に係る無線局方位角測定処理の処理手順を示すフローチャートである。
【００４２】
まず、特許文献１において提案されたＡＳテーブルの作成手順を用いて、図７及び図８の初期ＡＳテーブル作成処理（ステップＳ１）を実行する。すなわち、作成元の無線局１−ＡがＣＳＭＡ／ＣＡ方式でキャリアセンスを行いながら、第１のセットアップ信号をオムニパターンで他の無線局１−Ｂ，１−Ｃ，１−Ｄに対してブロードキャストで送信して作成フェーズを通知する。第１のセットアップ信号を受信した後、他の各無線局１−Ｂ，１−Ｃ，１−Ｄはそれぞれ、作成元の無線局１−Ａからの、０度から３３０度まで３０度毎に走査されるセクタパターンＳＰ１乃至ＳＰ１２（図９参照）による１２個のＲＱ１信号（第１の要求信号）をオムニパターンで受信して受信電界強度を測定するとともに、ＲＱ１信号を受信したときのＢＥＲを測定し、上述のようにＳＩＮＲに換算して計算する。これらの測定及び計算が終了した各他の無線局１−Ｂ，１−Ｃ，１−Ｄはキャリアセンスを行いながら、順次、キャリアを検出していない時間期間において計算結果のＳＩＮＲデータを無線局１−Ａに返信する。作成元の無線局１−Ａは、この返信に応答して周辺の他の無線局に関するＡＳテーブルの情報を作成してデータベースメモリ１５４に格納する。この手順を他の無線局１−Ｂ，１−Ｃ，１−Ｄが作成元となって繰り返して、当該無線アドホックネットワークにおける全ての無線局がＡＳテーブルの情報を有することとなる。
【００４３】
本実施形態では、上記の初期ＡＳテーブル作成処理の後に、以下の詳細ＡＳテーブル作成処理（図８のステップＳ２）を実行する。すなわち、ＡＳテーブルの情報を作成済みの無線局１−ＡがＣＳＭＡ／ＣＡ方式でキャリアセンスを行いながら、順次、キャリアを検出していない時間期間において第２のセットアップ信号を他の無線局１−Ｂ，１−Ｃ，１−Ｄに対してオムニパターンでブロードキャストで送信して詳細測定フェーズを通知する。このフェーズでは、無線局１−ＡはＲＱ２信号（第２の要求信号）をオムニパターンで他の無線局１−Ｂ，１−Ｃ，１−Ｄに対して送信され、このとき、他の無線局１−Ｂ，１−Ｃ，１−Ｄは各無線局１−Ｂ，１−Ｃ，１−Ｄが有するＡＳテーブルにおける無線局１−Ａに対する方位角（上記初期ＡＳテーブルにおいて最大のＳＩＮＲ値を有する３０度毎の簡易な方位角である。）の主ビームを有する中心セクタパターンと、上記中心セクタパターンの主ビームから−３０度回転された左側の左セクタパターンと、上記中心セクタパターンの主ビームから＋３０度回転された右側の右セクタパターンとの３つの指向性を有するセクタパターン（無線局１−Ｂでの３つのセクタパターンＳＰ９乃至ＳＰ１１を図１０に示す。）を用いてシーケンシャルに、上記ＲＱ２信号を受信して受信電界強度を測定する。以上の詳細ＡＳテーブル作成処理は、他の無線局１−Ｂ，１−Ｃ，１−Ｄが作成元となって繰り返して順次実行される。この処理で測定された、各作成元の相手局毎に、３つの受信電界強度の値に基づいて、上述のモノパルス測角処理を最大２回行って測角値の平均値を求める（図８のステップＳ３乃至Ｓ８）。
【００４４】
図８のステップＳ３では、左セクタパターンと中心セクタパターンとを用いる第１のモノパルス測角処理を実行し、ここで、左セクタパターンでＲＱ２信号を受信して測定した受信電界強度Ｐ１と、中心セクタパターンでＲＱ２信号を受信して測定した受信電界強度Ｐ２とに基づいて、上記数３を用いて無線局１−Ａの方位角θを計算する。ここで、いずれかの受信電界強度Ｐ１，Ｐ２が測定できないなどの場合は当該第１のモノパルス測角処理は完了しなかったと判断する。次いで、図８のステップＳ４では、中心セクタパターンと右セクタパターンとを用いる第２のモノパルス測角処理を実行し、ここで、中心セクタパターンでＲＱ２信号を受信して測定した受信電界強度Ｐ１と、右セクタパターンでＲＱ２信号を受信して測定した受信電界強度Ｐ２とに基づいて、上記数３を用いて無線局１−Ａの方位角θを計算する。ここで、いずれかの受信電界強度Ｐ１，Ｐ２が測定できないなどの場合は当該第２のモノパルス測角処理は完了しなかったと判断する。
【００４５】
さらに、図８のステップＳ５では、２つのモノパルス測角処理は完了したか否かが判断され、ＹＥＳのときはステップＳ６に進む一方、ＮＯのときはステップＳ７に進み、１つのモノパルス測角処理は完了したか否かが判断される。ここで、ステップＳ７でＹＥＳのときはステップＳ８に進む一方、ＮＯのときはステップＳ１に戻る。ステップＳ６では、各相手局毎に２つのモノパルス測角処理により測定された２つの測角値の平均値を計算して詳細方位角としてＡＳテーブルに格納し、ステップＳ２に戻る。この場合は、２つのモノパルス測角処理における測角値を平均化してより高い精度の測角値を求める。また、ステップＳ８では、各相手局毎に２つのモノパルス測角処理により測定された１つの測角値を詳細方位角としてＡＳテーブルに格納し、ステップＳ２に戻る。
【００４６】
上記の詳細測定フェーズにおいても、キャリアセンスにより他の無線局からの干渉が無いので、モノパルス測角処理における複数目標対処が不要となり、処理が容易となる。また、比較的モビリティーの低い無線局で構成される無線アドホックネットワークでは、一旦、ＡＳテーブルの情報が出来てからは、詳細測定フェーズ以降の手順のみで、ＡＳＴ情報を更新することも可能であり、３６０°の１２方向の測定から３方向のみの測定となり、従来技術の方法よりも本来の通信に伴うオーバーヘッドを低下させることが可能である。
【００４７】
以上説明したように、本実施形態によれば、以下の特有の効果を有する。
（１）特許文献１に開示された従来例の方法（以下、従来例の方法という。）によれば、本実施形態において記載した初期ＡＳテーブル作成処理を、ＡＳテーブルの作成の度に実行する必要があるが、本実施形態では、初期ＡＳテーブル作成処理を実行した後は、１つの作成元の無線局に対して、１回の第２のセットアップ信号の送信と例えば３回（少なくとも２回）のＲＱ２信号の送信のみの詳細ＡＳテーブル作成処理のみでよいので、本来の通信を行う時に付随するオーバーヘッドを大幅に低減できる。もし、オーバーヘッドが従来例の方法と同程度で良いとするなら、ＡＳテーブルの更新周期を短くしても良く、この場合、１２回／３回＝４なので、４倍の速さで更新しても良い。
（２）本実施形態で用いたセクタパターンでは、ビーム幅（３ｄＢ）が例えば９０度であって比較的広いので、３つのセクタパターンでも広い範囲がカバー出来るので、無線局が通信中においてある程度の範囲で移動しても手持ちのＡＳテーブルで対処することができる。
（３）本実施形態では、初期ＡＳテーブル作成処理を実行した後、詳細ＡＳテーブル作成処理を実行して、モノパルス測角処理で詳細方位角を計算できるので、従来例の方法に比較して、きわめて高い精度の方位角情報を得ることができる。
（４）本実施形態では、ＣＳＭＡ／ＣＡ方式を用いてキャリアセンスにより隣接する無線局に対して電波発射規制が行われているので、モノパルス処理における特有の課題である複数の目標に対して電波発射規制をする対処が不要となる。
（５）従来例の方法では、方位角の分解能を改善するためには、ビーム幅を狭くする必要があり、狭ビーム化を行うと、ＲＥ信号の送信回数が増えて、オーバーヘッドが増加してしまう。これに対して、本実施形態では、比較的広いビーム幅のままで対応可能となり、送信回数の増加による狭ビーム化が不要であり、上記狭ビーム化に伴うハードウエアの複雑化を防止できる。
【００４８】
さらに、図７乃至図１０に図示された実施形態に係る無線局方位角測定処理における一部を改良した変形例について、図１１乃至図１３を参照して以下に説明する。変形例に係る無線局方位角測定処理が実施形態に係る無線局方位角測定処理に比較して以下の点が異なる。
（１）図１２において、図８の初期ＡＳテーブル作成処理（ステップＳ１）に代えて、変形例された初期ＡＳテーブル作成処理（ステップＳ１Ａ）を実行する。
（２）図１２において、ステップＳ１ＡとステップＳ２との間に第３のモノパルス測角処理（ステップＳ１０）を実行する。
以下、これら相違点について詳説する。
【００４９】
図１１及び図１２の変形例された初期ＡＳテーブル作成処理（ステップＳ１Ａ）では、作成元の無線局１−ＡがＣＳＭＡ／ＣＡ方式でキャリアセンスを行いながら、第３のセットアップ信号をオムニパターンで他の無線局１−Ｂ，１−Ｃ，１−Ｄに対してブロードキャストで送信して作成フェーズを通知する。第３のセットアップ信号を受信した他の各無線局１−Ｂ，１−Ｃ，１−Ｄはそれぞれ、作成元の無線局１−ＡからのオムニパターンのＲＱ３信号の１２回の送信に対して、０度から３３０度まで３０度毎に走査されるセクタパターンＳＰ１乃至ＳＰ１２（図１３参照）を用いて受信して受信電界強度を測定して、実施形態のＳＩＮＲ値に代えて当該受信電界強度をデータベースメモリ１５４内のＡＳテーブルに格納する。この手順を他の無線局１−Ｂ，１−Ｃ，１−Ｄが作成元となって繰り返して、当該無線アドホックネットワークにおける全ての無線局がＡＳテーブルの情報を有することとなる。
【００５０】
次いで、第３のモノパルス測角処理（ステップＳ１０）では、各隣接する他の無線局毎に、上記ステップＳ１Ａで収集された１２回の受信電界強度に基づいて、互いに隣接するセクタパターンでの２つの受信電界強度で１回のモノパルス測角処理を実行し、これを１１回繰り返す。例えば、無線局１−Ｂにおいては、図１３の２つのセクタパターンＳＰ９，ＳＰ１０を用いて測定された受信電界強度に基づいて１回のモノパルス測角処理を実行して無線局１−Ａに対する詳細方位角を計算し、これを１１回繰り返す。そして、これら得られた詳細方位角（ただし、モノパルス測角処理が完了して計算されたものに限る。）を平均化して当該無線局１−Ａに対する詳細方位角として受信側の無線局１−Ｂのデータベースメモリ１５４内のＡＳテーブルに格納する。
【００５１】
なお、上記第３のモノパルス測角処理以降の処理については図８の処理と同様であり、図１４の処理も同様である。すなわち、比較的モビリティの低い無線局１で構成される無線アドホックネットワークにおいては、一旦、ＡＳテーブルの情報が出来てからは、詳細測定フェーズ以降のみの手順となることは実施形態と同じである。ただし、中心セクタパターンの主ビームの方位角の選択は、予め準備した１２方向のセクタパターンのうち、上記第３のモノパルス測角処理で測定された詳細方位角に最も近接する主ビームの方位角を有する１つのセクタパターンの方位角である。
【００５２】
以上説明したように、当該変形例によれば、上述の実施形態に比較して、初期ＡＳテーブル作成処理における、隣接する無線局数分のＲＥ信号の送信を省略できるので、本来の通信を行う時に付随するオーバーヘッドを大幅に低減できる。
【００５３】
以上の変形例では、１つの無線局１において、第３のモノパルス測角処理（ステップＳ１０）を実行するときに、１１回のモノパルス測角処理を実行しているが、本発明はこれに限らず、１２個の受信電界強度からより大きな３つの値を選択して、２回のモノパルス測角処理を実行してもよい。とって代わって、１２個の受信電界強度からより大きな２つの値を選択して、少なくとも１回のモノパルス測角処理を実行してもよい。
【００５４】
以上の変形例では、変形された初期ＡＳテーブル作成処理の後、詳細ＡＳテーブル作成処理を実行しているが、本発明はこれに限らず、前者の変形された初期ＡＳテーブル作成処理のみを実行してもよいし、もしくは、前者の処理を繰り返し実行してもよい。
【００５５】
以上の実施形態及び変形例において、ＡＳテーブルは、ＳＩＮＲ値を計算して格納しているが、本発明はこれに限らず、測定された受信電界強度、もしくは、測定されたＢＥＲに基づいて換算計算されたＣＩＮＲ値を格納してもよい。
【００５６】
従来技術の項で説明したように、特許文献１に記載された方位角測定処理では、全方位を走査するために、ＳＩＮＲの測定を要求するＲＱ信号を３０度毎で１２回送信した後、ＲＱ信号を受信した受信局からその無線局の数分だけその応答信号であるＲＥ信号を送信側無線局で受信する必要があり、本来の通信を行う前のオーバーヘッドが長くなるという問題点があった。これに対して、実施形態においては、初期ＡＳテーブル処理は必要であるが、それ以降は、詳細ＡＳテーブル作成処理において、３回のＲＱ２信号で処理が終了する。また、変形例においては、変形された初期ＡＳテーブル作成処理において、１２回のＲＱ３信号で処理が終了する。従って、本発明に係る実施形態や変形例では、特許文献１に記載された従来技術の方位角測定処理に比較してオーバーヘッドを大幅に低減できる。
【００５７】
【実施例】
本発明者らは、実施形態に係る無線アドホックネットワークのシステムを用いてシミュレーションを行ったので、その結果を以下に示す。当該シミュレーションでは、セクタパターンの３ｄＢ幅θ_３ｄＢを９０度とし、上記数４におけるＡ_ＳＮＲを２４ｄＢとしてビームの重ね合わせ（隣接する２つのセクタパターンの主ビームの方位角の差（図４の例では、θ_Ｃ−θ_Ｌである。）をいう。すなわち、これは、セクタパターンをステアリング走査するときの隣接する２つの設定角の差である。）に対する標準偏差σを求めると、次の表のようになる。
【００５８】
【表１】
――――――――――――――――――――
ビームの重ね合わせ標準偏差σ
――――――――――――――――――――
（１／３）×θ３_ｄＢ９．９
（２／３）×θ３_ｄＢ４．５
（３／３）×θ３_ｄＢ２．５
（４／３）×θ３_ｄＢ４．８
――――――――――――――――――――
【００５９】
表１の結果から明らかなように、ビームの重ね合わせ、すなわちモノパルス測角処理で用いる隣接する２つのセクタパターンの主ビームの方位角の差を、各セクタパターンの３ｄＢ幅と実質的に同一にすれば、標準偏差σは最小値となり、詳細方位角測定値のバラツキを最小限にできる。
【００６０】
【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における無線局の方位角測定方法又は装置によれば、複数の無線局のうちのサービスエリア内の各無線局に対する、所定の方位角毎の、受信電界強度、受信信号対干渉雑音比又は搬送波対干渉雑音比である信号測定値を予め測定して信号測定値テーブルとして記憶装置に記憶し、上記各無線局からの送信信号を、上記信号測定値テーブルにおける最大値の信号測定値を有する方位角の主ビームのセクタパターンを含む互いに隣接する少なくとも２つのセクタパターンを用いてそれぞれ受信電界強度を測定し、上記測定した各受信電界強度に基づいて、モノパルス測角処理を用いて、予め測定された上記２つのセクタパターンの差パターンをその和パターンで除算した商パターンを上記２つのセクタパターンの主ビームの方位角間で直線近似して最大の受信電界強度を有する、上記送信信号を送信した無線局の方位角を計算する。従って、無線通信に先立って実行されるオーバーヘッドの処理を短縮できるとともに、１つの無線局から他の複数の無線局への方向を、従来技術に比較して高い精度で測定することができる。
【００６１】
また、本発明に係る無線ネットワークにおける無線局の方位角測定方法又は装置によれば、複数の無線局のうちのサービスエリア内の各無線局からの送信信号を、所定の方位角毎の互いに隣接する少なくとも２つのセクタパターンを用いてそれぞれ受信電界強度を測定し、上記測定した各受信電界強度に基づいて、モノパルス測角処理を用いて、予め測定された上記２つのセクタパターンの差パターンをその和パターンで除算した商パターンを上記２つのセクタパターンの主ビームの方位角間で直線近似して最大の受信電界強度を有する、上記送信信号を送信した無線局の方位角を計算する。従って、無線通信に先立って実行されるオーバーヘッドの処理を短縮できるとともに、１つの無線局から他の複数の無線局への方向を、従来技術に比較して高い精度で測定することができる。
【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】本実施形態で用いる、無線局１−Ａの自局ＡＳテーブルの一例を示す図である。
【図４】本実施形態に係る無線局方位角測定処理において用いる左セクタパターンと右セクタパターンとを示す電界強度の方位角特性のグラフである。
【図５】本実施形態に係る無線局方位角測定処理において用いる和パターンＳ（θ）と差パターンＤ（θ）を示す電界強度の方位角特性のグラフである。
【図６】本実施形態に係る無線局方位角測定処理において用いる、差パターンＤ（θ）を和パターンＳ（θ）で除算したときの商の特性を示す電界強度の方位角特性のグラフである。
【図７】本実施形態に係る無線局方位角測定処理の通信手順を示すシーケンスチャートである。
【図８】本実施形態に係る無線局方位角測定処理の処理手順を示すフローチャートである。
【図９】図８の無線局方位角測定処理のうちの初期ＡＳテーブル作成処理において用いる１２個のセクタパターンを示す平面図である。
【図１０】図８の無線局方位角測定処理のうちの詳細ＡＳテーブル作成処理において用いる３個のセクタパターンを示す平面図である。
【図１１】変形例に係る無線局方位角測定処理の通信手順を示すシーケンスチャートである。
【図１２】変形例に係る無線局方位角測定処理の処理手順を示すフローチャートである。
【図１３】図１２の無線局方位角測定処理のうちの初期ＡＳテーブル作成処理において用いる１２個のセクタパターンを示す平面図である。
【図１４】図１２の無線局方位角測定処理のうちの詳細ＡＳテーブル作成処理において用いる３個のセクタパターンを示す平面図である。
【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、
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、
１６０…拡散符号発生器。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for measuring an azimuth angle of a wireless station in a wireless network performing wireless communication in a wireless ad hoc network such as a wireless LAN provided with a plurality of wireless stations.
[0002]
[Prior art]
A wireless ad hoc network is characterized in that wireless communication between wireless terminals can be performed directly between wireless terminals without using an infrastructure such as a base station. In an actual wireless communication environment, there are dynamic fluctuations in which wireless terminals move freely. The wireless terminals themselves have functions such as routers and must adapt autonomously, and each wireless terminal needs to cooperate in a distributed manner. is there.
[0003]
In addition, in the case of terminals that cannot communicate directly because radio waves do not reach, communication is possible by performing multi-hop communication with other terminals as relay stations to the target terminal. This relay station selection method is routing in a wireless ad hoc network. In the conventional method of flooding route search packets based on an omnidirectional antenna, the load on the network is high and the performance is degraded. Therefore, periodically steer the directional beam by the set angle unit, measure the received electric field strength of each terminal, and include signal-to-interference noise power ratio (SINR) information for each radio station for each predetermined angle An AS table (Angle-SINR-Table) is created, and based on this AS table information, a relay wireless terminal having a good radio wave environment is searched, and communication with a directional beam is performed to suppress inter-channel interference. Patent Document 1 proposes a method for improving network performance. Further, Non-Patent Document 1 discloses angle measurement processing using an amplitude monopulse radar.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-244983.
[Non-Patent Document 1]
Masahiro Watanabe et al., "An example of radar angle measurement", 2000 IEICE Basic and Boundary Society Conference Proceedings, IEICE, A-17-20, September 2000.
[Non-Patent Document 2]
Takashi Ohira, “Toward the Commercialization of Adaptive Antennas”, Symposium of the 1999 Kansai Branch Joint Conference on Electrical Engineering, “Recent Microwave and Millimeter Wave Technology”, published by the Institute of Electrical Engineers of Japan, S8-1, pp. S41, November 14, 1999.
[Non-Patent Document 3]
Takashi Ohira et al., “Adaptive beam formation by microwave signal processing and proposal of electronically controlled waveguide (ESPAR) antenna”, IEICE Technical Report, IEICE, AP99-61, SAT99-61, pp . 9-14, July 1999.
[Non-Patent Document 4] Tano Tetsu et al., "M-CMA: Digital Signal Processing Algorithm for Adaptive Beamforming by Microwave Signal Processing", IEICE Technical Report, IEICE, AP99-62, SAT99-62, pp. 15-22, July 1999.
[0005]
[Problems to be solved by the invention]
However, in the azimuth angle measurement process described in Patent Document 1, for example, only the direction of the radio station every 30 degrees can be grasped, and the detailed azimuth angle of the radio station cannot be measured. Further, in the angle measurement process described in Non-Patent Document 1, it is possible to measure the azimuth angle in a more accurate direction using a radar. For example, only the direction from one automobile to another automobile is measured. There is a problem in that it is impossible to measure the azimuth angle of each wireless station in a wireless ad hoc network including a plurality of wireless stations.
[0006]
In addition, in the azimuth angle measurement process described in Patent Document 1, after scanning an RQ signal requesting SINR measurement 12 times every 30 degrees in order to scan all directions, the receiving station that received the RQ signal There is a problem that the RE signal, which is the response signal, needs to be received by the transmitting side radio station by the number of radio stations, and the overhead before performing the original communication becomes long.
[0007]
The object of the present invention is to solve the above problems and measure the direction from one radio station to another radio station with higher accuracy than in the prior art in a radio network having a plurality of radio stations. Another object of the present invention is to provide a method and apparatus for measuring the azimuth angle of a wireless station in a wireless network that can reduce overhead.
[0008]
[Means for Solving the Problems]
A wireless station azimuth measuring method in a wireless network according to a first aspect of the invention is a wireless station azimuth measuring method in a wireless network that includes a plurality of wireless stations and performs wireless communication between the wireless stations.
For each wireless station in the service area of the plurality of wireless stations, a signal measurement value that is a received electric field strength, a received signal-to-interference noise ratio, or a carrier-to-interference noise ratio for each predetermined azimuth angle is measured in advance. A first step of storing in a storage device as a signal measurement value table;
The transmission signal from each of the radio stations is received by using at least two sector patterns adjacent to each other including the sector pattern of the main beam having the azimuth angle having the maximum signal measurement value in the signal measurement value table. A quotient pattern obtained by dividing the difference pattern of the two sector patterns measured in advance by the sum pattern using monopulse angle measurement processing based on the measured received electric field strengths. And a second step of calculating an azimuth angle of a radio station that has transmitted the transmission signal and has a maximum received electric field strength by linear approximation between the azimuth angles of the main beam.
[0009]
In the wireless station azimuth measuring method in the wireless network, the second step is to transmit a transmission signal from each wireless station to an azimuth main beam having a maximum signal measured value in the signal measured value table. The received electric field strength is measured using at least three sector patterns adjacent to each other including the sector pattern, and based on the received electric field strengths measured in the two adjacent sector patterns, a monopulse angle measurement process is used. Each azimuth having a maximum received electric field intensity is obtained by linearly approximating a quotient pattern obtained by dividing the difference pattern of each of the two sector patterns measured in advance by the sum pattern between the azimuth angles of the main beams of the two sector patterns. And the average value of the calculated azimuth angles is estimated as the azimuth angle of the wireless station that transmitted the transmission signal. And wherein the door.
[0010]
A radio station azimuth measurement method in a radio network according to a second aspect of the invention is a radio station azimuth measurement method in a radio network that includes a plurality of radio stations and performs radio communication between the radio stations.
A transmission signal from each radio station in the service area of the plurality of radio stations is measured for each received electric field strength using at least two sector patterns adjacent to each other for each predetermined azimuth, A quotient pattern obtained by dividing the difference pattern of the two sector patterns measured in advance by the sum pattern using a monopulse angle measurement process based on the received electric field strength is linearly between the azimuth angles of the main beams of the two sector patterns. The method includes a first step of calculating an azimuth angle of a radio station that has transmitted the transmission signal and has a maximum received electric field strength.
[0011]
In the wireless station azimuth measuring method in the wireless network, after executing the processing of the first step, the transmission signal from each wireless station is closest to the azimuth calculated in the first step. Measure the received electric field strength using at least two adjacent sector patterns including the sector pattern of the main beam at the azimuth angle, and measure in advance using the monopulse angle measurement process based on each measured received electric field strength. The quotient pattern obtained by dividing the difference pattern of the two sector patterns by the sum pattern is linearly approximated between the azimuth angles of the main beams of the two sector patterns, and the transmission signal having the maximum received electric field strength is transmitted. The method further includes a second step of calculating the azimuth angle of the wireless station.
[0012]
In the azimuth angle measuring method of the radio station in the radio network, the second step includes transmitting a transmission signal from each radio station to a main azimuth angle having a maximum signal measurement value in the signal measurement value table. The received electric field strength is measured using at least three adjacent sector patterns including the sector pattern of the beam, and monopulse angle measurement processing is used based on the received electric field strengths measured in the two adjacent sector patterns. The quotient pattern obtained by dividing the difference pattern of each of the two sector patterns measured in advance by the sum pattern thereof is linearly approximated between the azimuth angles of the main beams of the two sector patterns to obtain the maximum received electric field strength. An azimuth angle is calculated, and the average value of the calculated azimuth angles is estimated as the azimuth angle of the wireless station that transmitted the transmission signal. Characterized in that it.
[0013]
An azimuth measuring apparatus for a wireless station in a wireless network according to a third aspect of the present invention is the azimuth measuring apparatus for a wireless station in a wireless network that includes a plurality of wireless stations and performs wireless communication between the wireless stations.
For each wireless station in the service area of the plurality of wireless stations, a signal measurement value that is a received electric field strength, a received signal-to-interference noise ratio, or a carrier-to-interference noise ratio for each predetermined azimuth angle is measured in advance. First control means for storing in a storage device as a signal measurement value table;
The transmission signal from each of the radio stations is received by using at least two sector patterns adjacent to each other including the sector pattern of the main beam having the azimuth angle having the maximum signal measurement value in the signal measurement value table. A quotient pattern obtained by dividing the difference pattern of the two sector patterns measured in advance by the sum pattern using monopulse angle measurement processing based on the measured received electric field strengths. And second control means for calculating the azimuth angle of the radio station that has transmitted the transmission signal and has a maximum received electric field strength by linear approximation between the azimuth angles of the main beams.
[0014]
In the azimuth measuring apparatus for a radio station in the radio network, the second control means sends a transmission signal from each radio station to an azimuth main beam having a maximum signal measurement value in the signal measurement value table. The received electric field strength is measured using at least three adjacent sector patterns including the sector pattern, and based on the received electric field strengths measured in the two adjacent sector patterns, the monopulse angle measurement process is used. Each azimuth having the maximum received electric field intensity is obtained by linearly approximating the quotient pattern obtained by dividing the difference pattern between the two sector patterns measured in advance by the sum pattern between the azimuth angles of the main beams of the two sector patterns. The angle is calculated, and the average value of the calculated azimuth angles is estimated as the azimuth angle of the wireless station that transmitted the transmission signal. And wherein the door.
[0015]
An apparatus for measuring a direction of a wireless station in a wireless network according to a fourth aspect of the present invention is an apparatus for measuring an azimuth angle of a wireless station in a wireless network that includes a plurality of wireless stations and performs wireless communication between the wireless stations.
A transmission signal from each radio station in the service area of the plurality of radio stations is measured for each received electric field strength using at least two sector patterns adjacent to each other for each predetermined azimuth, Based on the received electric field strength, a quotient pattern obtained by dividing the difference pattern of the two sector patterns measured in advance by the sum pattern using a monopulse angle measurement process is a straight line between the azimuth angles of the main beams of the two sector patterns. It is characterized by comprising first control means for calculating the azimuth angle of a radio station that has transmitted the transmission signal and has a maximum received electric field strength.
[0016]
In the azimuth measuring apparatus of the wireless station in the wireless network, after executing the processing of the first control means, the transmission signal from each wireless station is set to the azimuth calculated by the first control means. Receiving field strength is measured using at least two sector patterns adjacent to each other including sector patterns of adjacent main beams of azimuth angles, and based on each of the measured receiving field strengths, using monopulse angle measurement processing, A quotient pattern obtained by dividing the difference pattern of the two sector patterns measured in advance by the sum pattern is linearly approximated between the azimuth angles of the main beams of the two sector patterns to obtain the transmission signal having the maximum received electric field strength. A second control means for calculating the azimuth angle of the transmitted radio station is further provided.
[0017]
Further, in the azimuth measuring apparatus for a radio station in the radio network, the second control means may transmit the transmission signal from each radio station to the azimuth having the maximum signal measurement value in the signal measurement value table. The received electric field strength is measured using at least three adjacent sector patterns including the sector pattern of the main beam, and the monopulse angle measurement processing is performed based on the received electric field strengths measured in the two adjacent sector patterns. The quotient pattern obtained by dividing the difference pattern of each of the two sector patterns measured in advance by the sum pattern thereof is linearly approximated between the azimuth angles of the main beams of the two sector patterns to obtain the maximum received electric field strength. Each azimuth angle is calculated, and the average value of the calculated azimuth angles is estimated as the azimuth angle of the radio station that transmitted the transmission signal. Characterized in that it.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments according to the present invention will be described below with reference to the drawings.
[0019]
FIG. 1 is a plan layout view of a plurality of radio stations 1-1 to 1-9 (generally referred to by reference numeral 1) showing the configuration of an ad hoc radio network according to an embodiment of the present invention. 2 is a block diagram showing a configuration of each wireless station 1 in FIG.
[0020]
The wireless communication system of this embodiment is applied to a packet communication system of an ad hoc wireless network such as a wireless LAN. Each wireless station 1 can change the direction of the main beam as shown in FIG. The SINR for the wireless station 1 in the service area for each predetermined azimuth angle in the horizontal plane with the variable beam antenna 101 as the center is measured in advance, and the table (Angle SINR Table; hereinafter referred to as the AS table). 8 is performed, and the azimuth angle of other radio stations is determined by executing the radio station azimuth measurement process shown in the flowchart of FIG. 8 using the monopulse angle measurement process based on the AS table. It is characterized by measuring with higher accuracy than in the prior art.
[0021]
In the wireless communication system of this embodiment, as shown in FIG. 1, a plurality of wireless stations 1 are present in a plane and each wireless station 1 has a gain, transmission power, and reception sensitivity of the variable beam antenna 101. A predetermined service area determined by parameters such as, and can perform packet communication within the 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 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 transmission terminal, a relay station, or a destination terminal.
[0022]
Next, the device configuration of each radio station 1 will be described with reference to FIG. In FIG. 2, a radio station 1 includes a variable beam antenna 101, a directivity control unit 103 for controlling the directivity thereof, a circulator 102, a data packet transmission / reception unit having a data packet transmission unit 140 and a data packet reception unit 130. 104, a traffic monitor unit 105, a line control unit 106, and an upper layer processing unit 107.
[0023]
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 has a predetermined radio frequency. The carrier wave signal is subjected to spread spectrum modulation in accordance with the input communication transmission signal data using a predetermined communication channel spreading code generated by the spread code generator 160 by the CDMA method, and the modulated transmission signal is transmitted at a high frequency. Output to the machine 144. The high-frequency transmitter 144 performs processing such as amplification on the input transmission signal, and then transmits the variable signal from the variable beam antenna 101 to another wireless station 1 via the circulator 102. On the other hand, the communication signal received 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 received signal. After executing the above process, the data is output to the demodulator 132. The demodulator 132 demodulates the input received signal by spectrum despreading using the communication channel spreading code generated by the spreading code generator 160 in the CDMA system, and the demodulated received signal data is converted into an upper layer. The data is output to the processing device 107 and also output to the traffic monitor unit 105 for traffic monitoring.
[0024]
In this embodiment, the variable beam antenna 101 that is a directional antenna includes a plurality of antenna elements and a control unit 103 that controls the directivity thereof. For example, the variable beam antenna 101 has a predetermined beam width and ranges from 0 degrees to 330 degrees. Twelve sector patterns and omni patterns (omnidirectional patterns) having a main beam direction every 30 degrees are provided, and the main beam direction of each sector pattern is electrically controlled at a predetermined scanning interval of, for example, 30 degrees It can be changed by the antenna. Note that the variable beam antenna 101 may be, for example, a known phased array antenna device or an electronically controlled waveguide array antenna disclosed in Non-Patent Documents 2 to 4. The sector pattern refers to a fan-shaped radiation pattern having a predetermined main beam width, as shown in FIG.
[0025]
The traffic monitor unit 105 includes a search engine 152, an update engine 153, and a database memory 154. The traffic monitor unit 105 executes the radio station azimuth measurement process shown in FIG. 8, and the radio station 1 performs packet communication with other radio stations 1. The communication channel to be used is determined, and the designation data of the spread code corresponding to the decided communication channel is sent to the spread code generator 160 via the line control unit 106, so that the spread code generator 160 Is transmitted to the transmission timing control unit 141 via the line control unit 106, so that the transmission timing control unit 141 can transmit the specified time slot data corresponding to the determined communication channel to the transmission timing control unit 141. Writing and reading of transmission signal data for communication channel by the transmission buffer memory 142 Transmission signal for the communication channel by controlling the controls to be transmitted in the corresponding time slot.
[0026]
The search engine 152 of the traffic monitor unit 105 searches the 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 stores its own station AS table, other station AS table, routing table, and wireless station table.
[0027]
The local station AS table stored in advance in the database memory 154 has the SINR for each wireless station 1 in the service area for each predetermined azimuth in the horizontal plane centered on the local station, as shown in FIG. It is measured in advance and stored in a table format, and the detailed azimuth angle for each of the other radio stations 1 measured by executing the radio station azimuth measurement process of FIG. 8 is stored. Here, in order to measure SINR, a bit error rate (BER) is measured by transmitting and receiving data packets of a predetermined training pattern to and from each other radio station 1, and SINR determined by a modulation / demodulation method of radio communication. Is converted into SINR using a graph of the BER characteristic with respect to. For example, when the CDMA method is used, conversion can be performed using a graph of BER characteristics with respect to SINR. For example, when the QPSK differential detection method is used, a graph of BER characteristics with respect to carrier power to noise power ratio (CNR). Can be converted. That is, whether to use the carrier power to interference noise power ratio (hereinafter referred to as CINR) or SINR depends on the modulation / demodulation method used in the wireless system. In the present invention, any measurement value regarding co-channel interference noise may be used. Alternatively, the received electric field strength may be used instead.
[0028]
The other station AS table stored in the database memory 154 is an AS table in another wireless station 1 having the same format as the own station AS table, and is transmitted from another station by a predetermined packet transmission / reception control process. Acquired and stored in the database memory 154. Further, the routing table indicates the ID of the first hop station, the number of hops, and the update time for each radio station existing in the ad hoc radio network based on data packet data transmitted and received in the past. Store. Furthermore, the wireless station table stores IDs of wireless stations existing in the ad hoc wireless network based on data packet data transmitted and received in the past.
[0029]
Next, monopulse processing used in the radio station azimuth measurement processing according to the present embodiment will be described below. In the variable beam antenna 101 used in this embodiment, for example, when the direction of the main beam is 0 degree, the sector pattern having the main beam is referred to as a center sector pattern, and the direction of 30 degrees on the right side of the center sector pattern. This sector pattern is referred to as a right sector pattern, and a sector pattern in the direction of −30 degrees to the left of the central sector pattern is referred to as a left sector pattern. Assume that these sector pattern data are measured in advance by a known method and stored in the database memory 154.
[0030]
This monopulse processing uses the sector pattern having directivity in each of the two directions scanned by the right sector pattern and the central sector pattern or the central sector pattern and the left sector pattern to receive radio waves from other radio stations and And the angle θ of the direction of the other radio station and the standard deviation σ are calculated from the approximate straight line based on the sum and difference of the sector patterns in these two directions (see Non-Patent Document 1, for example). ).
[0031]
For example, when monopulse angle measurement processing is performed based on the left sector pattern and the central sector pattern adjacent to each other as shown in FIG. _C -Left scan angle θ _L = 30 degrees), the sum pattern S (θ) and the difference pattern D (θ), the 3 dB width θs of the sum pattern S (θ), and the difference pattern D (θ) are divided by the sum pattern S (θ). A quotient D (θ) / S (θ) pattern (hereinafter referred to as a quotient pattern) is calculated in advance as shown in FIGS. 5 and 6, and the center scanning angle θ in FIG. _C And left scanning angle θ _L Is approximated by a straight line, and the slope k of the straight line is calculated and stored in the database memory 154. Next, the received electric field strength P1 measured with the central sector pattern and the received electric field strength P2 measured with the left sector pattern are measured, and the angle θ of the direction of another radio station to be measured can be calculated as follows. . The same applies to the monopulse angle measurement process based on the adjacent central sector pattern and right sector pattern.
[0032]
First, the relationship between the two received electric field strengths P1 and P2 and the quotient D (θ) / S (θ) is expressed by the following equation.
[0033]
[Expression 1]
(P1-P2) / (P1 + P2)
= D (θ) / S (θ)
[0034]
On the other hand, as is apparent from FIG.
[0035]
[Expression 2]
θ = θs · (D (θ) / S (θ)) / k
[0036]
Substituting the above equation 1 into the above equation 2, the following equation is obtained.
[0037]
[Equation 3]
θ = θs · {(P1−P2) / (P1 + P2)} / k
[0038]
Therefore, based on the received electric field strengths P1 and P2 measured using the two sector patterns adjacent to each other, the angle θ in the direction of the other radio station can be calculated using the above Equation 3. Furthermore, the value of the standard deviation σ when measured a plurality of times n can be calculated using the following equation.
[0039]
[Expression 4]
σ = θs / k√ ((A _SNR ) ・ N)
[0040]
Where A _SNR Is the average value of the SINR of the two received electric field strengths P1 and P2. For example, when the number of observations n = 2 as monopulse processing, for example, monopulse angle measurement processing using the left sector pattern and center sector pattern and monopulse angle measurement processing using the center sector pattern and right sector pattern are executed. Thus, a method of averaging the measured values can be used.
[0041]
FIG. 7 is a sequence chart showing a communication procedure of the radio station azimuth measuring process according to the present embodiment, and FIG. 8 is a flowchart showing a processing procedure of the radio station azimuth measuring process according to the present embodiment.
[0042]
First, using the AS table creation procedure proposed in Patent Document 1, the initial AS table creation process (step S1) shown in FIGS. 7 and 8 is executed. In other words, the first radio signal 1-A broadcasts the first setup signal to the other radio stations 1-B, 1-C, 1-D in an omni pattern while performing carrier sense by the CSMA / CA system. Send in to notify the creation phase. After receiving the first set-up signal, each of the other radio stations 1-B, 1-C, 1-D is updated every 30 degrees from 0 degrees to 330 degrees from the original radio station 1-A. The 12 RQ1 signals (first request signals) from the scanned sector patterns SP1 to SP12 (see FIG. 9) are received as omni patterns to measure the received electric field strength, and the BER when the RQ1 signal is received is measured. Measure and calculate in SINR as described above. Each of the other radio stations 1-B, 1-C, 1-D that has completed the measurement and calculation performs the carrier sense and sequentially transmits the calculated SINR data in the time period in which no carrier is detected. Reply to 1-A. In response to this reply, the creating radio station 1-A creates AS table information related to other neighboring radio stations and stores it in the database memory 154. This procedure is repeated with the other radio stations 1-B, 1-C, 1-D being created, and all the radio stations in the radio ad hoc network have AS table information.
[0043]
In the present embodiment, after the initial AS table creation process described above, the following detailed AS table creation process (step S2 in FIG. 8) is executed. That is, while the wireless station 1-A that has already created the information of the AS table performs carrier sensing in the CSMA / CA scheme, the second setup signal is sent to the other wireless stations 1- 1 in a time period during which no carrier is detected sequentially. B, 1-C, 1-D are broadcast in an omni pattern to notify the detailed measurement phase. In this phase, the radio station 1-A transmits an RQ2 signal (second request signal) to the other radio stations 1-B, 1-C, 1-D in an omni pattern. The stations 1-B, 1-C, 1-D are azimuth angles with respect to the radio station 1-A in the AS table of the radio stations 1-B, 1-C, 1-D (the maximum SINR value in the initial AS table). And a central sector pattern having a main beam of 30 degrees), a left sector pattern on the left rotated by −30 degrees from the main beam of the central sector pattern, and the central sector pattern Using a sector pattern having three directivities with the right sector pattern on the right side rotated by +30 degrees from the main beam (three sector patterns SP9 to SP11 in the radio station 1-B are shown in FIG. 10). The catcher Le, measures the reception field strength received the RQ2 signal. The detailed AS table creation process described above is repeatedly executed sequentially with the other radio stations 1-B, 1-C, 1-D being created. Based on the values of the three received electric field strengths measured for each counterpart station measured in this process, the above-mentioned monopulse angle measurement process is performed twice at maximum to obtain the average value of the angle measurement values (FIG. 8). Steps S3 to S8).
[0044]
In step S3 of FIG. 8, the first monopulse angle measurement process using the left sector pattern and the center sector pattern is executed. Here, the received electric field intensity P1 measured by receiving the RQ2 signal with the left sector pattern, and the center Based on the received electric field strength P2 measured by receiving the RQ2 signal with the sector pattern, the azimuth angle θ of the radio station 1-A is calculated using the above equation (3). If one of the received electric field strengths P1 and P2 cannot be measured, it is determined that the first monopulse angle measurement process has not been completed. Next, in step S4 of FIG. 8, a second monopulse angle measurement process using the center sector pattern and the right sector pattern is performed. Here, the received electric field strength P1 measured by receiving the RQ2 signal with the center sector pattern and Based on the received electric field strength P2 measured by receiving the RQ2 signal in the right sector pattern, the azimuth angle θ of the radio station 1-A is calculated using the above equation 3. Here, when one of the received electric field strengths P1 and P2 cannot be measured, it is determined that the second monopulse angle measurement process has not been completed.
[0045]
Further, in step S5 of FIG. 8, it is determined whether or not the two monopulse angle measurement processes are completed. If YES, the process proceeds to step S6. If NO, the process proceeds to step S7, and one monopulse angle measurement process is performed. It is determined whether or not is completed. Here, when YES is determined in the step S7, the process proceeds to a step S8, and when NO, the process returns to the step S1. In step S6, the average value of the two measured values measured by the two monopulse angle measuring processes for each counterpart station is calculated and stored in the AS table as a detailed azimuth, and the process returns to step S2. In this case, the angle measurement values in the two monopulse angle measurement processes are averaged to obtain an angle measurement value with higher accuracy. In step S8, one measured angle value measured by two monopulse angle measuring processes for each counterpart station is stored in the AS table as a detailed azimuth, and the process returns to step S2.
[0046]
Even in the above detailed measurement phase, since there is no interference from other radio stations due to carrier sense, it is not necessary to deal with multiple targets in the monopulse angle measurement process, and the process becomes easy. In addition, in a wireless ad hoc network composed of wireless stations with relatively low mobility, once the AS table information is made, it is possible to update the AST information only by the procedure after the detailed measurement phase. The measurement in 12 directions at 360 ° is performed in only 3 directions, and the overhead associated with the original communication can be reduced as compared with the conventional method.
[0047]
As described above, according to the present embodiment, the following specific effects are obtained.
(1) According to the conventional method disclosed in Patent Document 1 (hereinafter referred to as the conventional method), the initial AS table creation process described in the present embodiment is executed each time an AS table is created. Although it is necessary, in the present embodiment, after the initial AS table creation process is executed, one second setup signal is transmitted to one creation source radio station and, for example, three times (at least twice). Only the detailed AS table creation process of only the transmission of the RQ2 signal is sufficient, so that the overhead accompanying the original communication can be greatly reduced. If the overhead is comparable to that of the conventional method, the AS table update cycle may be shortened. In this case, 12 times / 3 times = 4, so the update speed is four times faster. Also good.
(2) In the sector pattern used in this embodiment, the beam width (3 dB) is, for example, 90 degrees and is relatively wide. Therefore, a wide range can be covered with three sector patterns. Even if it moves within the range, it can be dealt with with the AS table on hand.
(3) In this embodiment, after executing the initial AS table creation process, the detailed AS table creation process is executed, and the detailed azimuth angle can be calculated by the monopulse angle measurement process. A highly accurate azimuth angle information can be obtained.
(4) In this embodiment, radio wave emission is regulated for adjacent radio stations by carrier sense using the CSMA / CA method, so that radio waves are emitted for a plurality of targets that are unique problems in monopulse processing. No need to take action to regulate launch.
(5) In the conventional method, in order to improve the resolution of the azimuth angle, it is necessary to narrow the beam width. When the beam is narrowed, the number of transmissions of the RE signal increases and the overhead increases. End up. On the other hand, in this embodiment, it is possible to cope with a relatively wide beam width, it is not necessary to narrow the beam by increasing the number of transmissions, and the hardware complexity associated with the narrow beam can be prevented.
[0048]
Further, a modification in which a part of the radio station azimuth measurement processing according to the embodiment shown in FIGS. 7 to 10 is improved will be described below with reference to FIGS. 11 to 13. The radio station azimuth measurement processing according to the modification differs from the radio station azimuth measurement processing according to the embodiment in the following points.
(1) In FIG. 12, a modified initial AS table creation process (step S1A) is executed in place of the initial AS table creation process (step S1) in FIG.
(2) In FIG. 12, the third monopulse angle measurement process (step S10) is executed between step S1A and step S2.
Hereinafter, these differences will be described in detail.
[0049]
In the modified initial AS table creation process (step S1A) of FIG. 11 and FIG. 12, the creation source radio station 1-A performs carrier sense by the CSMA / CA method, and the third setup signal is an omni pattern. Broadcast to other radio stations 1-B, 1-C, 1-D to notify the creation phase. Each of the other radio stations 1-B, 1-C, 1-D that received the third setup signal respectively transmits omni-pattern RQ3 signal 12 times from the source radio station 1-A. The received electric field strength is measured using the sector patterns SP1 to SP12 (see FIG. 13) scanned every 30 degrees from 0 degree to 330 degrees, and the received electric field intensity is used instead of the SINR value of the embodiment. Are stored in the AS table in the database memory 154. This procedure is repeated with the other radio stations 1-B, 1-C, 1-D being created, and all the radio stations in the radio ad hoc network have AS table information.
[0050]
Next, in the third monopulse angle measurement process (step S10), for each adjacent other radio station, 2 in the sector pattern adjacent to each other based on the 12 received electric field strengths collected in step S1A. One monopulse angle measurement process is executed with one received electric field strength, and this is repeated 11 times. For example, the radio station 1-B performs one monopulse angle measurement process based on the received electric field strength measured using the two sector patterns SP9 and SP10 of FIG. Calculate the azimuth and repeat this 11 times. Then, the obtained detailed azimuth angles (however, limited to those calculated after the monopulse angle measurement processing is completed) are averaged to obtain the detailed azimuth angle for the radio station 1-A as the receiving radio station 1-. The data is stored in the AS table in the B database memory 154.
[0051]
The processing after the third monopulse angle measurement processing is the same as the processing in FIG. 8, and the processing in FIG. 14 is also the same. That is, in the wireless ad hoc network configured with the wireless station 1 having relatively low mobility, once the information in the AS table is created, the procedure is performed only after the detailed measurement phase. However, the main beam azimuth of the central sector pattern is selected from among the 12 directional sector patterns prepared in advance, the main beam azimuth closest to the detailed azimuth measured by the third monopulse angle measurement process. Is the azimuth angle of one sector pattern.
[0052]
As described above, according to the modification, transmission of RE signals for the number of adjacent wireless stations in the initial AS table creation process can be omitted as compared with the above-described embodiment, so that original communication is performed. The overhead associated with sometimes can be greatly reduced.
[0053]
In the above modification, when the third monopulse angle measurement process (step S10) is executed in one radio station 1, eleven monopulse angle measurement processes are executed, but the present invention is not limited to this. Alternatively, the three monopulse angle measurement processes may be executed by selecting three larger values from the 12 received electric field strengths. Alternatively, at least one monopulse angle measurement process may be executed by selecting two larger values from the 12 received electric field strengths.
[0054]
In the above modification, after the modified initial AS table creation process, the detailed AS table creation process is executed. However, the present invention is not limited to this, and only the former modified initial AS table creation process is executed. Alternatively, the former process may be repeatedly executed.
[0055]
In the above embodiments and modifications, the AS table calculates and stores the SINR value, but the present invention is not limited to this, and is converted based on the measured received electric field strength or the measured BER. The calculated CINR value may be stored.
[0056]
As described in the section of the prior art, in the azimuth angle measurement process described in Patent Document 1, in order to scan all directions, after transmitting an RQ signal that requires SINR measurement 12 times every 30 degrees, There is a problem in that it is necessary to receive the RE signal, which is the response signal, from the receiving station that has received the RQ signal by the number of the wireless station, and the overhead before performing the original communication becomes long. It was. On the other hand, in the embodiment, the initial AS table processing is necessary, but thereafter, in the detailed AS table creation processing, the processing ends with three RQ2 signals. Further, in the modified example, in the modified initial AS table creation process, the process ends with 12 RQ3 signals. Therefore, in the embodiment and the modification according to the present invention, the overhead can be significantly reduced as compared with the conventional azimuth angle measurement process described in Patent Document 1.
[0057]
【Example】
Since the present inventors performed simulation using the system of the wireless ad hoc network according to the embodiment, the results are shown below. In this simulation, the 3 dB width θ of the sector pattern _3dB Is 90 degrees, and A in the above equation 4 _SNR Is superposed to be 24 dB (the difference in the azimuth angles of the main beams of two adjacent sector patterns (in the example of FIG. _C −θ _L It is. ). That is, this is the difference between two adjacent setting angles when steering scanning the sector pattern. The standard deviation σ for) is as shown in the following table.
[0058]
[Table 1]
――――――――――――――――――――
Beam overlap Standard deviation σ
――――――――――――――――――――
(1/3) × θ3 _dB 9.9
(2/3) × θ3 _dB 4.5
(3/3) × θ3 _dB 2.5
(4/3) × θ3 _dB 4.8
――――――――――――――――――――
[0059]
As is apparent from the results in Table 1, the difference in main beam azimuth between two adjacent sector patterns used in beam superposition, that is, monopulse angle measurement processing, is substantially the same as the 3 dB width of each sector pattern. Then, the standard deviation σ becomes the minimum value, and the variation in the detailed azimuth angle measurement value can be minimized.
[0060]
【The invention's effect】
As described in detail above, according to the azimuth angle measuring method or apparatus for a radio station in a radio network according to the present invention, for each radio station in a service area among a plurality of radio stations, for each predetermined azimuth angle, A signal measurement value that is a received electric field strength, a received signal-to-interference noise ratio, or a carrier-to-interference noise ratio is measured in advance and stored in a storage device as a signal measurement value table. The reception field strength is measured using at least two adjacent sector patterns including the sector pattern of the main beam of the azimuth having the maximum signal measurement value in the value table, and based on the measured reception field strengths. The quotient patterns obtained by dividing the difference pattern of the two sector patterns measured in advance by the sum pattern using the monopulse angle measurement process are Having the greatest received electric field strength by linear approximation in the main beam azimuth Kakuma sector pattern, it calculates the azimuth of the radio station which has transmitted the transmission signal. Therefore, overhead processing executed prior to wireless communication can be shortened, and the direction from one wireless station to other wireless stations can be measured with higher accuracy than in the prior art.
[0061]
Further, according to the method or apparatus for measuring the azimuth angle of a radio station in a radio network according to the present invention, the transmission signals from the radio stations in the service area of the plurality of radio stations are adjacent to each other for each predetermined azimuth angle. The received electric field strength is measured using at least two sector patterns, and based on each measured received electric field strength, the difference pattern between the two sector patterns measured in advance is measured using monopulse angle measurement processing. The quotient pattern divided by the sum pattern is linearly approximated between the azimuth angles of the main beams of the two sector patterns to calculate the azimuth angle of the radio station that has transmitted the transmission signal and has the maximum received electric field strength. Therefore, overhead processing executed prior to wireless communication can be shortened, and the direction from one wireless station to other wireless stations can be measured with higher accuracy than in the prior art.
[Brief description of the drawings]
FIG. 1 is a plan layout view of a plurality of radio stations 1-1 to 1-9 constituting an ad hoc radio network according to an embodiment of the present invention.
2 is a block diagram showing an internal configuration of each radio station 1 in FIG. 1. FIG.
FIG. 3 is a diagram illustrating an example of a local station AS table of a wireless station 1-A used in the present embodiment.
FIG. 4 is a graph of azimuth characteristics of electric field strength showing a left sector pattern and a right sector pattern used in radio station azimuth measurement processing according to the present embodiment.
FIG. 5 is a graph of azimuth characteristics of electric field strength showing a sum pattern S (θ) and a difference pattern D (θ) used in the radio station azimuth measurement processing according to the present embodiment.
FIG. 6 is a graph of the azimuth characteristics of electric field strength showing the quotient characteristics when the difference pattern D (θ) is divided by the sum pattern S (θ) used in the radio station azimuth measurement processing according to the present embodiment. is there.
FIG. 7 is a sequence chart showing a communication procedure of radio station azimuth measurement processing according to the present embodiment.
FIG. 8 is a flowchart showing a processing procedure of radio station azimuth measurement processing according to the present embodiment.
9 is a plan view showing twelve sector patterns used in the initial AS table creation process in the wireless station azimuth measurement process of FIG. 8. FIG.
10 is a plan view showing three sector patterns used in the detailed AS table creation process in the wireless station azimuth measurement process of FIG. 8. FIG.
FIG. 11 is a sequence chart showing a communication procedure of radio station azimuth measurement processing according to a modification.
FIG. 12 is a flowchart showing a processing procedure of radio station azimuth measurement processing according to a modification.
13 is a plan view showing twelve sector patterns used in the initial AS table creation process in the wireless station azimuth measurement process of FIG.
14 is a plan view showing three sector patterns used in the detailed AS table creation process in the wireless station azimuth measurement process of FIG. 12. FIG.
[Explanation of symbols]
1, 1-1 to 1-9 ... wireless station,
101 ... Variable beam antenna,
102 ... circulator,
103 ... Direction control unit,
104 ... packet transmission / reception unit,
105 ... Traffic monitor section,
106 ... line control unit,
107 ... upper layer processing apparatus,
130: Packet receiver,
131 ... high frequency receiver,
132: demodulator,
133: Receive buffer memory,
140 ... packet transmitter,
141. Transmission timing control unit,
142 ... transmission buffer memory,
143 ... modulator,
144 ... high frequency transmitter,
151... Management control unit,
152 ... Search engine,
153 ... Update engine,
154 ... Database memory,
160. Spread code generator.

Claims

In the method for measuring the azimuth angle of a wireless station in a wireless network comprising a plurality of wireless stations and performing wireless communication between the wireless stations,
Each radio station included in the plurality of radio stations becomes a measurement radio station, and the measurement radio station performs the following steps:
Signal measurement that is a received electric field strength, a received signal-to-interference noise ratio, or a carrier-to-interference noise ratio for each predetermined azimuth angle for each of the plurality of wireless stations other than the measurement wireless station in the service area. A first step of measuring values in advance and storing them in a storage device as a signal measurement value table;
An omni pattern transmitted from each of the radio stations excluding the measurement radio station receives a setup signal notifying the detailed measurement phase, and responds to the setup signal in response to the setup signal from the radio stations other than the measurement radio station. Measure the received electric field strength of the transmission signal transmitted in a pattern using at least two adjacent sector patterns including the main beam sector pattern of the azimuth having the maximum signal measurement value in the signal measurement value table. A quotient pattern obtained by dividing the difference pattern of the two sector patterns measured in advance by the sum pattern using a monopulse angle measurement process based on the measured received electric field strengths. A radio station that has transmitted the above transmission signal and has a maximum received electric field strength by linearly approximating between the azimuth angles of the beams Azimuth measuring method of a wireless station in a wireless network which comprises a second step of calculating an azimuth angle.

In the second step, a setup signal for notifying the detailed measurement phase, which is transmitted in an omni pattern from each of the radio stations excluding the measurement radio station, is received, and in response to the setup signal, the measurement radio station is The transmission signals transmitted in an omni pattern from each of the radio stations except for the above are used at least three sector patterns adjacent to each other including the main beam sector pattern of the azimuth having the maximum signal measurement value in the signal measurement value table. The received electric field strength is measured, and based on the received electric field strengths measured with the two adjacent sector patterns, the difference pattern between the two sector patterns measured in advance is obtained using monopulse angle measurement processing. The quotient pattern divided by the sum pattern is linearly approximated between the azimuth angles of the main beam of each of the above two sector patterns 2. An azimuth angle having a maximum received electric field strength is calculated, and an average value of the calculated azimuth angles is estimated as an azimuth angle of a wireless station that has transmitted the transmission signal. Method for measuring the azimuth angle of a wireless station in a wireless network.

In the method for measuring the azimuth angle of a wireless station in a wireless network comprising a plurality of wireless stations and performing wireless communication between the wireless stations,
Each radio station included in the plurality of radio stations becomes a measurement radio station, and the measurement radio station performs the following steps:
Receiving a first setup signal notifying the initial measurement phase, which is transmitted in an omni pattern from each of the plurality of wireless stations excluding the measurement wireless station within the service area, and receiving the first setup signal; In response to the signal, transmit signal transmitted in an omni pattern from each of the radio stations excluding the measurement radio station, and measure the received electric field strength using at least two adjacent sector patterns for each predetermined azimuth angle. A quotient pattern obtained by dividing the difference pattern of the two sector patterns measured in advance by the sum pattern using a monopulse angle measurement process based on the measured received electric field strengths. First calculating the azimuth angle of the radio station that has transmitted the transmission signal and has a maximum received electric field strength by linear approximation between the azimuth angles of the beams And the step,
A second setup signal that is transmitted in an omni pattern from each of the wireless stations excluding the measurement wireless station and notifies the detailed measurement phase is received, and the measurement wireless station is excluded in response to the second setup signal. The transmission signal transmitted in an omni pattern from each wireless station uses at least two sector patterns adjacent to each other including the sector pattern of the main beam having the azimuth angle closest to the azimuth angle calculated in the first step. The received electric field strength is measured, and a quotient pattern obtained by dividing the difference pattern of the two sector patterns measured in advance by the sum pattern using monopulse angle measurement processing based on each measured received electric field strength. The transmission signal having the maximum received electric field strength is obtained by linear approximation between the azimuth angles of the main beams of the two sector patterns. Azimuth measuring method of a wireless station in a wireless network which comprises a second step of calculating the azimuth of the line stations.

The second step receives a second setup signal for notifying the detailed measurement phase, transmitted in an omni pattern from each of the radio stations excluding the measurement radio station, and in response to the setup signal, the measurement A transmission signal transmitted in an omni pattern from each of the wireless stations excluding the wireless station is converted into at least three sectors adjacent to each other including a sector pattern of an azimuth main beam having a maximum signal measurement value in the signal measurement value table. The received electric field strength is measured using each pattern, and based on the respective received electric field strengths measured by the two adjacent sector patterns, the monopulse angle measurement process is used to measure each of the two sector patterns measured in advance. The quotient pattern obtained by dividing the difference pattern by the sum pattern is directly between the azimuth angles of the main beams of the two sector patterns. Claims each azimuth is calculated, the calculated average value of a plurality of azimuth angles, and estimating the azimuth of the radio station which has transmitted the transmission signal having the maximum reception field strength was approximated 4. A method for measuring an azimuth angle of a wireless station in the wireless network according to 3 .

In a wireless station azimuth measuring apparatus in a wireless network comprising a plurality of wireless stations and performing wireless communication between wireless stations,
Each radio station included in the plurality of radio stations is a measurement radio station, and the measurement radio station is
Signal measurement that is a received electric field strength, a received signal-to-interference noise ratio, or a carrier-to-interference noise ratio for each predetermined azimuth angle for each of the plurality of wireless stations other than the measurement wireless station in the service area. First control means for measuring values in advance and storing them in a storage device as a signal measurement value table;
An omni pattern transmitted from each of the radio stations excluding the measurement radio station receives a setup signal notifying the detailed measurement phase, and responds to the setup signal in response to the setup signal from the radio stations other than the measurement radio station. Measure the received electric field strength of the transmission signal transmitted in a pattern using at least two adjacent sector patterns including the main beam sector pattern of the azimuth having the maximum signal measurement value in the signal measurement value table. A quotient pattern obtained by dividing the difference pattern of the two sector patterns measured in advance by the sum pattern using a monopulse angle measurement process based on the measured received electric field strengths. A radio station that has transmitted the above transmission signal and has a maximum received electric field strength by linearly approximating between the azimuth angles of the beams Azimuth measuring device of a wireless station in a wireless network, characterized in that a second control means for calculating the azimuth angle.

The second control means receives a setup signal for notifying the detailed measurement phase, transmitted in an omni pattern from each of the radio stations excluding the measurement radio station, and in response to the setup signal, the measurement radio station A transmission signal transmitted in an omni pattern from each of the above radio stations except for the at least three sector patterns adjacent to each other including the sector pattern of the main beam of the azimuth having the maximum signal measurement value in the signal measurement value table. Each of the received electric field strengths, and based on the respective received electric field strengths measured at the two adjacent sector patterns, the difference pattern between the two sector patterns measured in advance using monopulse angle measurement processing. Is a linear approximation between the azimuth angles of the main beam of each of the above two sector patterns. Largest each azimuth calculated with the received field strength, the calculated average value of a plurality of azimuth angles, according to claim 5, characterized in that estimating the azimuth of the radio station which has transmitted the transmission signal Te For measuring the azimuth angle of a wireless station in a wireless network.

In a wireless station azimuth measuring apparatus in a wireless network comprising a plurality of wireless stations and performing wireless communication between wireless stations,
Each radio station included in the plurality of radio stations is a measurement radio station, and the measurement radio station is
Receiving a first setup signal notifying the initial measurement phase, which is transmitted in an omni pattern from each of the plurality of wireless stations excluding the measurement wireless station within the service area, and receiving the first setup signal; In response to the signal, transmit signal transmitted in an omni pattern from each of the radio stations excluding the measurement radio station, and measure the received electric field strength using at least two adjacent sector patterns for each predetermined azimuth angle. A quotient pattern obtained by dividing the difference pattern of the two sector patterns measured in advance by the sum pattern using a monopulse angle measurement process based on the measured received electric field strengths. First calculating the azimuth angle of the radio station that has transmitted the transmission signal and has a maximum received electric field strength by linear approximation between the azimuth angles of the beams And control means,
A second setup signal that is transmitted in an omni pattern from each of the wireless stations excluding the measurement wireless station and notifies the detailed measurement phase is received, and the measurement wireless station is excluded in response to the second setup signal. A transmission signal transmitted in an omni pattern from each of the radio stations is converted into at least two sector patterns adjacent to each other including the main beam sector pattern of the azimuth angle closest to the azimuth angle calculated by the first control means. A quotient pattern obtained by dividing the difference pattern between the two sector patterns measured in advance by using the monopulse angle measurement process based on each measured received field strength The transmission signal having the maximum received electric field strength is transmitted by linearly approximating between the azimuth angles of the main beams of the two sector patterns. Azimuth measuring device of a wireless station in a wireless network, characterized by further comprising a second control means for calculating the azimuth of the line stations.

The second control means receives a second setup signal notifying the detailed measurement phase and transmitted in an omni pattern from each of the radio stations excluding the measurement radio station, and responds to the second setup signal. The transmission signals transmitted in an omni pattern from each of the radio stations excluding the measurement radio station are adjacent to each other including the sector pattern of the main beam having the azimuth angle having the maximum signal measurement value in the signal measurement value table. Each of the received electric field strengths is measured using at least three sector patterns, and each of the two measured in advance using a monopulse angle measurement process based on the received electric field strengths measured with two adjacent sector patterns. The quotient pattern obtained by dividing the difference pattern of two sector patterns by the sum pattern is the azimuth angle of the main beam of each of the above two sector patterns. A linear approximation is performed to calculate each azimuth angle having the maximum received electric field strength, and an average value of the calculated azimuth angles is estimated as an azimuth angle of the wireless station that transmitted the transmission signal. The azimuth measuring apparatus for a radio station in a radio network according to claim 7 .