JP3562421B2

JP3562421B2 - Wireless packet relay route construction method

Info

Publication number: JP3562421B2
Application number: JP2000042777A
Authority: JP
Inventors: 智明小川; 栄亮工藤; 徹大津
Original assignee: Nippon Telegraph and Telephone Corp
Current assignee: Nippon Telegraph and Telephone Corp
Priority date: 2000-02-21
Filing date: 2000-02-21
Publication date: 2004-09-08
Anticipated expiration: 2020-02-21
Also published as: JP2001237875A

Description

【０００１】
【発明の属する技術分野】
本発明は、無線回線によって情報を伝達し、直接電波の届かない無線局間の信号送受を可能とするように無線局が中継機能を有する無線パケットネットワークに係わる。特に、直接電波の届かない無線局間の信号送受を行う際の経路選択方法に関する。
【０００２】
【従来の技術】
図１、図２及び図３は、無線回線によって情報を伝達し、直接電波の届かない無線局間の信号送受を可能とするように無線局が中継機能を有する無線パケットネットワークの従来の経路選択方法の例（「ＴｈｅＤｙｎａｍｉｃＳｏｕｒｃｅＲｏｕｔｉｎｇＰｒｏｔｏｃｏｌｆｏｒＭｏｂｉｌｅＡｄＨｏｃＮｅｔｗｏｒｋｓ」、ＪｏｓｈＢｒｏｃｈ，ＤａｖｉｄＢ．Ｊｏｈｎｓｏｎ，＆ＤａｖｉｄＡ．Ｍａｌｔｚ，ＩＥＴＦＭＡＮＥＴＷｏｒｋｉｎｇＧｒｏｕｐＩＮＴＥＲＮＥＴ−ＤＲＡＦＴ，２２Ｏｃｔ．１９９９．）である。図２の参照符号は、図１の無線局の参照符号に相当し、無線局１０１から無線局１０７に対しパケットを送信するものとする。
【０００３】
無線局１０１にて送信要求が発生したとき、データの送信要求が発生したことを示す送信要求信号を生成して、無線局１０１と直接通信することのできる無線局（１０２、１０４、１０８）に送信する。
【０００４】
図３は、送信要求信号のフレーム構成図である。送信要求信号は、送信要求信号であることを示す信号ヘッダ（３０１）と、送信要求信号の識別を行うための送信要求信号ＩＤ（３０２）と、無線局１０１の無線局ＩＤを示す発信無線局ＩＤ（３０３）と、無線局１０７の無線局ＩＤを示す宛先無線局ＩＤ（３０４）と、中継無線局として用いられる無線局を示す中継無線局ＩＤ（３０５）とで構成される。中継無線局ＩＤは、中継される無線局の数だけ、経路構築の際に中継無線局の処理の中で付加されていく。無線局１０１は、無線局１０１の保持する送信要求信号リストに、発生した送信要求のＩＤを示す送信要求信号ＩＤを付加する。
【０００５】
図４は、送信要求信号リストの説明図である。これは、各無線局が受信した送信要求信号が、その無線局ですでに処理したものか否かを判別するためのリストであり、各無線局が処理した送信要求信号の送信要求信号ＩＤ（４０１）が書き込まれる。
【０００６】
次に、送信要求信号を受信した無線局の処理について述べる。
【０００７】
図５は、送信要求信号を受信した無線局の処理のフローチャートである。無線局１０１と直接通信が可能である無線局１０２、１０４、１０８は、無線局１０１の送信した送信要求信号を受信する（５０１）。無線局１０１からの送信要求信号を受信した無線局１０２は、無線局１０２の保持する送信要求信号リストを参照し、送信要求信号リストに受信した無線局１０１からの送信要求信号がないことを確認する（５０２）。送信要求信号がないことの確認は、受信した無線局１０１からの送信要求信号の中に含まれる送信要求信号ＩＤが、無線局１０２の保持する送信要求信号リストに含まれないことを確認することによって行われる。無線局１０１からの送信要求信号が無線局１０２の送信要求信号リストに含まれるとき、無線局１０２は、無線局１０１からの送信要求信号を、すでに受信しているので、それ以降の他の無線局への該送信要求信号の送信を中止する（５０３）。無線局１０２が、無線局１０１からの送信要求信号を送信要求信号リストに含まないことを確認したとき、無線局１０１で行った処理と同様に、無線局１０２の保持する送信要求信号リストに送信要求信号ＩＤを付け加える（５０４）。次に、無線局１０２は、受信した送信要求信号中の宛先無線局ＩＤと無線局１０２の無線局ＩＤとを比較する（５０５）。宛先無線局ＩＤと無線局１０２の無線局ＩＤが一致するとき、無線局１０２が送信要求に対する宛先無線局であることがわかり、後に述べる送信要求信号に対する返信処理を行う（５０６）。一方、宛先無線局ＩＤと無線局１０２の無線局ＩＤが一致しないとき、中継無線局として無線局１０２を使用することを示すために、無線局１０１から受信した送信要求信号の末尾に無線局１０２の無線局ＩＤを中継無線局ＩＤとして付加し（５０７）、送信要求信号を送信する（５０８）。無線局１０１からの送信要求信号を受信した無線局１０４、１０８は、無線局１０２と同様の操作を行う。各無線局が送信要求信号リストを保持し、受信した送信要求信号が過去に受信したものと同じかどうかを確認することによって、一度送信要求信号を受信した無線局の重複した処理と、送信要求信号が無限に同じ無線局間でループして転送されることを防ぐ。
【０００８】
次に、送信要求信号に対する返信処理について述べる。図１において、送信要求信号を受信した無線局１０７が上記処理例の中で、自無線局の無線局ＩＤと送信要求信号に含まれる宛先無線局ＩＤが一致する、即ち無線局１０７が上記例の送信要求に対する宛先無線局であるとわかったとき、無線局１０７が受信した送信要求信号中の中継無線局ＩＤの列が、送信要求を発生した無線局１０１から宛先無線局である無線局１０７までの中継経路となる。同じ送信要求信号ＩＤを持つ送信要求信号のうち、最も早く宛先無線局に到着した送信要求信号中の中継無線局ＩＤの列を、宛先無線局までの最短経路として選択する。
【０００９】
ここでは、無線局１０１−無線局１０２−無線局１０３−無線局１０７の経路が選択されたとする。無線局１０７が行う送信要求信号に対する返信処理は、次の手順で行われる。まず、無線局１０７の保持する要求返信信号リストに、受信した送信要求信号ＩＤを書き加える。次に、要求返信信号を作成し、無線局１０７の直接通信できる無線局に送信する。
【００１０】
図６は、要求返信信号リストである。要求返信信号リストには、各無線局が受信した送信要求信号中の送信要求信号ＩＤ（６０１）が書き込まれる。
【００１１】
図７は、要求返信信号のフレーム構成図である。要求返信信号は、要求返信信号であることを示す信号ヘッダ（７０１）と、受信した送信要求信号の送信要求ＩＤ（７０２）と、受信した送信要求信号の発信無線局ＩＤ（７０３）と、受信した送信要求信号の宛先無線局ＩＤ（７０４）と、受信した送信要求信号中の中継無線局ＩＤの列（７０５）によって構成される。
【００１２】
次に、要求返信信号を受信した無線局の処理について述べる。
【００１３】
図８は、要求返信信号を受信した無線局の処理のフローチャートである。図１によると、無線局１０７が送信した要求返信信号は、無線局１０７の直接通信できる無線局１０３、無線局１０６、無線局１０９によって受信される（８０１）。要求返信信号を受信した無線局１０３は、自無線局即ち無線局１０３の無線局ＩＤが、受信した要求返信信号中の中継無線局ＩＤの列に含まれるかどうか確認する（８０２）。自無線局の無線局ＩＤが、受信した要求返信信号中の中継無線局ＩＤの列に含まれないとき、自無線局は経路の中継無線局として使用されていないことを示しており、受信した要求返信信号に対する処理を中止する（８０３）。自無線局の無線局ＩＤが、受信した要求返信信号中の中継無線局ＩＤの列に含まれるとき、次の処理を行う。即ち、無線局１０３が保持する要求返信信号リストの中に受信した要求返信信号の送信要求信号ＩＤが含まれるかどうかを確認する（８０４）。要求返信信号リストに要求返信信号の送信要求信号ＩＤが含まれるとき、受信した要求返信信号は、すでに無線局１０３によって受信されているため、受信した要求返信信号に対する処理を中止する（８０５）。要求返信信号リストに要求返信信号の送信要求信号ＩＤが含まれないとき、無線局１０３の保持する要求返信信号リストに、受信した要求返信信号の送信要求信号ＩＤを書き加える（８０６）。次に、受信した要求返信信号中の発信無線局ＩＤが、無線局１０３の無線局ＩＤと一致するかどうかを確認する（８０７）。受信した要求返信信号中の発信無線局ＩＤが、自無線局の無線局ＩＤと一致するとき、即ち送信要求を発した無線局に経路が構築された旨を伝える信号が到達したとき、構築した経路を用いたデータ送信の処理を行う（８０８）。受信した要求返信信号中の発信無線局ＩＤが、自無線局の無線局ＩＤと一致しないとき、無線局１０３は、受信した要求返信信号をそのまま送信する（８０９）。即ち無線局１０７は到達した送信要求信号に含まれる経路情報の逆の経路を辿って無線局１０１まで要求返信信号を送信する。
【００１４】
【発明が解決しようとする課題】
本来、無線回線は、そのときの状況によって回線の品質が変化する。そのため、通信のできていた通信経路でも、その後通信ができなくなることがある。従来の中継経路構築方法では、一度通信経路を選択すると、その経路の回線切断を検出するまでその経路を使用する。回線切断の検出は、切断された無線区間の送信側の無線局が一定時間以上受信側の無線局からの受信確認信号が返ってこないことを確認して、その無線局が無線局Ａに通知することで可能であるが、経路切断を検出する時間と経路を再構築するのに要する時間の分だけ無線局Ｂでの信号到着時刻に遅延ゆらぎが生じる欠点があった。この遅延揺らぎが大きいと、音声等のリアルタイム性が要求される信号の転送には、このような無線パケットネットワークを用いることができなかった。
【００１５】
また、回線の切断が検出されるまで同一の経路を利用し続けるため、トラヒックの変動等によって中継無線局等での転送遅延時間が変動することにより、選択した経路が最短経路でなくなり、結果としてネットワーク全体の効率が低下する問題があった。
【００１６】
従来の中継経路構築方法は、１つの最適な主経路を構築するための方法である。従って、同時に複数の迂回経路を構築しようとすれば各無線局で経路構築のための処理を繰り返し行うことになるため経路構築が収束しない問題がある。また、１本の主経路を構築した後に代替経路を構築しようとしても、既に構築された主経路と同じ経路を構築してしまうため、複数の中継経路を構築できなかった。更に、複数の経路を同時に構築し始める場合、主経路と迂回経路とで互いの経路の状態を考慮に入れた経路の構築が難しかった。
【００１７】
【課題を解決するための手段】
そこで、本発明の無線パケットの中継経路構築方法は、パケット信号を中継する機能を有する複数の無線局から構成された無線ネットワークであって、送信要求信号は、送信要求信号ＩＤと、発信無線局ＩＤと、宛先無線局ＩＤと、無線局を中継する毎に追加して格納される中継無線局ＩＤ列とから構成され、無線局は、既に処理した送信要求信号ＩＤを格納する送信要求信号リストを有しており、送信要求信号を受信した当該無線局は、送信要求信号リストに該送信要求信号の送信要求信号ＩＤが含まれていれば、該送信要求信号に対する処理を終了する第１の段階と、そうでなければ、送信要求信号リストに該送信要求信号ＩＤを追加する第２の段階と、当該無線局の無線局ＩＤと宛先無線局ＩＤとが一致すれば、返信処理をする第３の段階と、そうでなければ、送信要求信号に当該無線局ＩＤを中継無線局ＩＤとして追加する第４の段階と、当該無線局が直接通信可能な無線局へ送信要求信号を送信する第５の段階とを有する主通信経路を構築する中継経路構築方法において、前記主通信経路を構築した後に、他の迂回通信経路を構築するために、迂回送信要求信号は、重複フラグと、迂回送信要求信号ＩＤと、発信無線局ＩＤと、宛先無線局ＩＤと、既に構築された主通信経路の中継無線局ＩＤ列と、無線局を中継する毎に追加して格納される迂回中継無線局ＩＤ列とから構成され、無線局は、既に処理した迂回送信要求信号ＩＤを格納する迂回送信要求信号リストと、通信可能な無線局を格納した通信可能無線局リストとを有しており、迂回送信要求信号を受信した当該無線局は、迂回送信要求信号リストに該迂回送信要求信号の迂回送信要求信号ＩＤが含まれていれば、該迂回送信要求信号に対する処理を終了する第６の段階と、そうでなければ、主通信経路の中継無線局ＩＤ列の中に、迂回中継無線局ＩＤ列の最後の迂回中継無線局ＩＤに続いて当該無線局の無線局ＩＤが存在し、且つ重複フラグが立っていない場合に、該迂回送信要求信号に対する処理を終了する第７の段階と、中継無線局ＩＤ列の中に、迂回中継無線局ＩＤ列の最後の迂回中継無線局ＩＤに続いて当該無線局の無線局ＩＤが存在しないか、又は、前記中継無線局ＩＤ列の中に、迂回中継無線局ＩＤ列の最後の迂回中継無線局ＩＤに続いて当該無線局の無線局ＩＤが存在し、且つ重複フラグが立っている場合に、迂回送信要求信号リストに該迂回送信要求信号ＩＤを追加する第８の段階と、当該無線局の無線局ＩＤと宛先無線局ＩＤとが一致すれば、返信処理をして当該迂回送信要求信号に対する処理を終了する第９の段階と、そうでなければ、当該無線局の通信可能無線局リスト内に、迂回送信要求信号を送信した無線局、及び、主通信経路で使用されている無線局、以外に無線局が存在しない場合に、重複フラグが立てられ、そうでない場合に重複フラグが立てられない第１０の段階と、迂回送信要求信号に当該無線局ＩＤを迂回中継無線局ＩＤとして追加する第１１の段階と、当該無線局が直接通信可能な無線局へ迂回送信要求信号を送信する第１２の段階とを有する方法である。
【００１８】
また、本発明の他の実施形態によれば、通信可能無線局リストは、当該無線局が他の無線局が一定時間毎に間欠に送信する通信可能信号を受信し、該通信可能信号の通信可能無線局ＩＤとその受信時間とを記録したものであり、該通信可能無線局ＩＤに相当する通信可能信号が所定の監視周期時間の間に受信されなかった場合、当該通信可能無線局ＩＤを通信可能無線局リストから削除することも好ましい。
【００１９】
また、本発明の他の実施形態によれば、無線局は、当該無線局における受信トラヒック量、送信トラヒック量、受信トラヒック変動量及び／又は送信トラヒック変動量を観測し、その観測情報を、迂回送信要求信号内に、無線局を中継する毎に追加して格納することも好ましい。
【００２０】
更に、本発明の他の実施形態によれば、第９の段階における返信処理は、迂回送信要求信号内の観測情報の列をそのまま返信し、発信無線局に該観測情報の列が通知されることも好ましい。
【００２１】
【発明の実施の形態】
図１を用いて本発明における経路構築の方法を説明する。無線局１０１が直接通信を行うことのできない無線局１０７へのデータ送信の要求が発生し、１回の送信要求に対して２本の経路を構築してデータの送信を行う例について述べる。なお、本実施例では、経路数が２本の場合を示すが、本発明において構築する経路の数は、複数であり２本とは限らない。
【００２２】
図９は、通信可能無線局信号のフレーム構成図である。本発明では、各無線局は直接通信できる無線局に自分の存在を認知させるために通信可能無線局信号を間欠的に送信する。通信可能無線局信号は、通信可能無線局信号を示す信号ヘッダ（９０１）と、通信可能無線局信号を発した無線局の無線局ＩＤを示す通信可能無線局ＩＤ（９０２）とで構成される。通信可能無線局信号を受信した無線局は、通信可能無線局信号中の通信可能無線局ＩＤから、通信可能無線局信号を受信した無線局の直接通信可能な範囲内に、通信可能無線局信号を発した無線局が存在することを認知し、通信可能無線局信号を受信した無線局の保持する通信可能無線局リストに受信した通信可能無線局信号に含まれる通信可能無線局ＩＤと、通信可能無選局信号を受信した時刻とを書き加える。
【００２３】
図１０は、通信可能無線局リストの説明図である。通信可能無線局リストは、通信可能無線局ＩＤと受信時刻（１００１）のフィールドで構成されるレコードの集合である。このように通信可能無線局リストは受信された無線局ＩＤを書き込むことで作成されるが、今まで受信できていた無線局がその移動により通信可能範囲外に遠ざかってしまった場合には、該当する無線局からの通信可能無線局信号が受信できなくなる。この場合には、通信可能無線局信号の間欠周期よりも長い無線局監視周期を設けて、現在時刻と通信可能無線局リストの受信時刻を比較し、無線局監視周期よりも時間が経過した無線局ＩＤを削除することで、無線局の移動に対してダイナミックな通信可能無線局リストの作成が可能となる。もちろんこの場合には、通信可能無線局信号を受信するたびにリストの受信時刻を更新していくこととなる。あるいは、通信無線局リストは、図１０に示された通信可能無線局ＩＤのみの集合とし、各無線局ＩＤ毎に無線局監視周期のタイマを設けて、通信可能無線局信号を受信すれば、タイマをリセットし、タイマがタイムアウトした場合に該当する無線局ＩＤを削除するようにしても良い。このように無線局の移動によるネットワーク構成の動的な変化に対して、各無線局が通信可能無選局信号の送受信を行い、自律的に通信可能エリア内に存在する無線局を確認することによって、全体としてアドホックネットワークが確立される。
【００２４】
最初に、無線局１０１から無線局１０７までの経路（経路Ｘ）を１本構築する。無線局１０１が経路Ｘが構築された旨を伝える要求返信信号を受信したとき、無線局１０１は、経路Ｘを用いて無線局１０７へデータの送信を開始し、同時に迂回経路構築を開始する。
【００２５】
図１１は、迂回経路構築を開始する処理のフローチャートである。図１において、経路Ｘの要求返信信号が無線局１０１によって受信される、即ち送信要求を発した無線局に到着したとき、無線局１０１の保持する迂回送信要求信号リストに、経路Ｘの要求返信信号中の送信要求信号ＩＤを加える（１１０１）。
【００２６】
図１２は、迂回送信要求信号リストの説明図である。迂回送信要求信号リストは、経路Ｘの要求返信信号中の送信要求信号ＩＤ（１２０１）のフィールドで構成されるレコードの集合である。次に、無線局１０１の保持する通信可能無線局リストに含まれる無線局の数を確認する（１１０２）。無線局１０１の保持する通信可能無線局リストに含まれる無線局の数が１のとき、即ち無線局１０１の直接通信できる無線局が１つだけのとき、無線局１０１の送信する迂回送信要求信号に含まれる重複フラグを立てる（１１０３）。無線局１０１の保持する通信可能無線局リストに含まれる無線局の数が１より大きいとき、即ち無線局１０１の直接通信できる無線局が複数存在するとき、無線局１０１の送信する迂回送信要求信号に含まれる重複フラグを立てない（１１０４）。重複フラグは、迂回経路構築の際に、経路Ｘに含まれる無線局間の無線リンクと、迂回経路に含まれる無線局間の無線リンクとが重複する無線局間の無線リンクを使用することを許容するか否かを決定するためのものである。許容の判断は迂回送信要求信号を受信した無線局側で行われる。無線局１０１の保持する通信可能無線局リストに含まれる無線局の数が１である、即ち無線局１０１の直接通信できる無線局が１つだけのとき、無線局１０１と、無線局１０１の直接通信できる範囲内に存在する唯一の無線局との間の無線リンクは、経路Ｘの中で使用されているが、無線局１０１と無線局１０１の直接通信できる範囲内に存在する他の無線局との間の無線リンクは存在しないために、迂回経路でも、経路Ｘと重複する無線局１０１と、無線局１０１の直接通信できる範囲内に存在する唯一の無線局との間の無線リンクを使用する。
【００２７】
図１３は、経路Ｘと迂回経路とで重複する無線リンクを使用する必要のあるネットワーク構成図である。図１３において、無線局１３０１で無線局１３１０に対する送信要求が発生するとき、無線局１３０１と無線局１３０２との間の無線リンクと、無線局１３０５と無線局１３０６との間の無線リンクと、無線局１３０９と無線局１３１０との間の無線リンクとは、経路Ｘと迂回経路とで重複して使用する無線リンクである。
【００２８】
図１４は、迂回送信要求信号のフレーム構成図である。迂回送信要求信号は、送信される信号が迂回送信要求信号であることを示す信号ヘッダ（１４０１）と、経路Ｘの無線局間の無線リンクと迂回経路の無線局間の無線リンクとの重複を許容するか否かを判断するために用いる重複フラグ（１４０２）と、受信した要求返信信号に含まれる送信要求信号ＩＤ（１４０３）と、無線局１０１の無線局ＩＤを示す発信無線局ＩＤ（１４０４）と、宛先無線局である無線局１０７の無線局ＩＤを示す宛先無線局ＩＤ（１４０５）と、経路Ｘの要求返信信号中の中継無線局ＩＤの列（１４０６）と、迂回経路で用いられる無線局を示す迂回中継無線局ＩＤ（１４０７）とで構成される。生成した迂回送信要求信号を、無線局１０１が送信する（１１０５）。
【００２９】
図１４には記載されていないが、各中継無線局で測定されたトラヒック等の観測情報を、迂回送信要求信号内に、無線局を中継する毎に追加して格納することもできる。この観測情報としては、当該無線局における受信トラヒック量、送信トラヒック量、受信トラヒック変動量及び／又は送信トラヒック変動量がある。また、これらの観測情報は、宛先無線局における返信処理によって、迂回送信要求信号内の観測情報の列がそのまま返信され、発信無線局に該観測情報の列が通知されることもできる。これにより、トラヒックの変化に応じて経路を選択することができる。特に、ネットワーク全体のトラヒック変動量が大きいシステムにおいて有効である。
【００３０】
次に、迂回送信要求信号を受信した無線局の処理について述べる。
【００３１】
図１５は、迂回送信要求信号を受信した無線局の処理のフローチャートである。図１によると、無線局１０１が送信した迂回送信要求信号は、無線局１０１の直接通信できる範囲内に存在する無線局１０２、無線局１０４、無線局１０８によって受信される（１５０１）。迂回送信要求信号を受信した無線局１０８は、無線局１０８の保持する迂回送信要求信号リストに、受信した迂回送信要求信号中の送信要求信号ＩＤが含まれるか確認する（１５０２）。無線局１０８の保持する迂回送信要求信号リストに、受信した迂回送信要求信号中の送信要求信号ＩＤが含まれるとき、無線局１０８は受信した迂回送信要求信号と同じ送信要求信号ＩＤを持つ迂回送信要求信号に対する処理を行っていることを示しているため、受信した迂回送信要求信号に対する処理を中止する（１５０３）。無線局１０８の保持する迂回送信要求信号リストに、受信した迂回送信要求信号中の送信要求信号ＩＤが含まれないとき、受信した迂回送信要求信号中の迂回中継無線局ＩＤの末尾の無線局ＩＤと、無線局１０８の無線局ＩＤとの無線リンクが、受信した迂回送信要求信号中の経路Ｘの中継無線局ＩＤの列の中のいずれかの無線リンクと、重複するか否かを確認する（１５０４）。受信した迂回送信要求信号中の迂回中継無線局ＩＤの末尾の無線局ＩＤと、自無線局の無線局ＩＤとの無線リンクが、受信した迂回送信要求信号中の経路Ｘの中継無線局ＩＤの列の中のいずれかの無線リンクと重複するとき、経路Ｘで使用された無線リンクと、無線局１０８に迂回送信要求信号を送信した無線局と無線局１０８との間の無線リンクとは、重複していることを示しており、受信した迂回送信要求信号中の重複フラグが立っているか確認する（１５０５）。受信した迂回送信要求信号中の重複フラグが立っていないとき、無線局１０８に迂回送信要求信号を送信した無線局は、無線局１０８以外の無線局との間に無線リンクを構築することができることを示しているため、無線局１０８は受信した迂回送信要求信号に対して処理を中止する（１５０６）。受信した迂回送信要求信号中の重複フラグが立っているとき、無線局１０８に迂回送信要求信号を送信した無線局は、無線局１０８以外の無線局との間に無線リンクを構築することができないことを示しているため、経路Ｘと重複する無線リンクを迂回経路で使用することを許容するために、無線局１０８は受信した迂回送信要求信号に対して処理を継続する。また、受信した迂回送信要求信号中の迂回中継無線局ＩＤの末尾の無線局ＩＤと、自無線局の無線局ＩＤとの無線リンクが、受信した迂回送信要求信号中の経路Ｘの中継無線局ＩＤの列の中のいずれかの無線リンクと重複しないときも、無線局１０８は受信した迂回送信要求信号に対して処理を継続する。処理を継続する場合、無線局１０８の保持する迂回送信要求信号リストに、受信した迂回送信要求信号中の送信要求信号ＩＤを書き加える（１５０７）。次に、受信した迂回送信要求信号中の宛先無線局ＩＤが、無線局１０８の無線局ＩＤと一致するか否か確認する（１５０８）。受信した迂回送信要求信号中の宛先無線局ＩＤが自無線局の無線局ＩＤと一致する場合、自無線局が宛先無線局であり、後に述べる迂回経路構築に対する返信処理を行う（１５０９）。受信した迂回送信要求信号中の宛先無線局ＩＤが、自無線局の無線局ＩＤと一致しないとき、即ち自無線局が送信要求に対する宛先でないとき、無線局１０８が保持する通信可能無線局リストを参照し、無線局１０８の直接通信できる範囲内に存在する無線局の数を調べる（１５１０）。無線局１０８が迂回送信要求信号を送信するとき、その信号を受信することのできる無線局が、無線局１０８に迂回送信要求信号を送信した無線局、または第１経路で使用する無線リンクを構築する無線局しか存在しないとき、無線局１０８が送信する迂回送信要求信号は、重複フラグを立てる（１５１１）。そのとき、無線局１０８は受信した迂回送信要求信号中の経路Ｘの中継無線局ＩＤの列を参照して、重複フラグを立てる判断を行う。無線局１０８が保持する通信可能無線局リスト中の無線局ＩＤが、無線局１０８に迂回送信要求信号を送信した無線局の無線局ＩＤと、迂回送信要求信号中の経路Ｘの中継無線局の中に無線局１０８を含んでさらに無線局１０８の前後２機の無線局の無線局ＩＤ以外に存在するとき、即ち無線局１０８が、迂回送信要求信号を経路Ｘで使用する無線リンク以外の無線リンクを用いて送信することができるとき、無線局１０８の送信する迂回送信要求信号の重複フラグを立てない（１５１２）。次に、無線局１０８は迂回送信要求信号中の迂回中継無線局ＩＤに、自無線局即ち無線局１０８の無線局ＩＤを付加し（１５１３）、迂回送信要求信号を送信する（１５１４）。経路Ｘの経路構築時と同様に、無線局１０１からの迂回送信要求信号を受信した無線局１０２、１０４は、無線局１０８と同様の操作を行う。各無線局が迂回送信要求信号リストを保持し、受信した迂回送信要求信号が過去に受信したものと同じかどうかを確認することによって、一度迂回送信要求信号を受信した無線局の重複した処理の防止と、迂回送信要求信号が無限に同じ無線局間でループして転送されることを防ぎ、ネットワークのトラヒックを軽減する。
【００３２】
次に、迂回送信要求信号に対する返信処理について述べる。図１において、経路Ｘ構築時と同様に、迂回送信要求信号を受信した無線局１０７が上記例の迂回経路構築の処理の中で自無線局の無線局ＩＤと迂回送信要求信号に含まれる宛先無線局ＩＤが一致する、即ち無線局１０７が上記例の送信要求に対する宛先無線局であるとわかったとき、無線局１０７が受信した迂回送信要求信号中の迂回中継無線局ＩＤの列が、送信要求を発生した無線局１０１から宛先無線局である無線局１０７までの迂回経路となる。同じ送信要求信号ＩＤを持つ迂回送信要求信号のうち、最も早く宛先無線局に到着した迂回送信要求信号中の迂回中継無線局ＩＤの列が、宛先無線局までの最短経路の迂回経路として選択される。ここでは、無線局１０１−無線局１０８−無線局１０９−無線局１０７の経路が迂回経路として選択されたとする。無線局１０７が行う迂回送信要求信号に対する返信処理は、次の手順で行われる。まず、無線局１０７の保持する迂回要求返信信号リストに、受信した迂回送信要求信号ＩＤを書き加える。
【００３３】
図１６は、迂回要求返信信号リストの説明図である。迂回要求返信信号リストは、受信した迂回要求返信信号中の送信要求信号ＩＤ（１６０１）をフィールドに持つレコードの集合である。
【００３４】
次に、迂回要求返信信号を作成する。
【００３５】
図１７は、迂回要求返信信号のフレーム構成図である。迂回要求返信信号は、迂回要求返信信号であることを示す信号ヘッダ（１７０１）と、受信した迂回送信要求信号中の送信要求信号ＩＤ（１７０２）と、受信した迂回送信要求信号中の発信無線局ＩＤ（１７０３）と、受信した迂回送信要求信号中の宛先無線局ＩＤ（１７０４）と、受信した迂回送信要求信号中の経路Ｘの中継無線局ＩＤの列（１７０５）と、受信した迂回送信要求信号中の迂回中継無線局ＩＤの列（１７０６）によって構成され、無線局１０７は、作成した迂回要求返信信号を送信する。
【００３６】
次に、迂回要求返信信号を受信した無線局の処理について述べる。
【００３７】
図１８は、迂回要求返信信号を受信した無線局の処理のフローチャートである。図１によると、無線局１０７が送信した迂回要求返信信号は、無線局１０７の直接通信できる範囲内に存在する無線局１０３、無線局１０６、無線局１０９によって受信される（１８０１）。迂回要求返信信号を受信した無線局１０９は、自無線局即ち無線局１０９の無線局ＩＤが、受信した迂回要求返信信号中の迂回中継無線局ＩＤに含まれるかどうか確認する（１８０２）。自無線局の無線局ＩＤが、受信した迂回要求返信信号中の迂回中継無線局ＩＤに含まれないとき、自無線局は迂回経路の中継無線局として使用されていないことを示しており、受信した迂回要求返信信号に対する処理を中止する（１８０３）。自無線局の無線局ＩＤが、受信した迂回要求返信信号中の迂回中継無線局ＩＤに含まれるとき、次の処理を行う。即ち、無線局１０９が保持する迂回要求返信信号リストの中に受信した迂回要求返信信号の送信要求信号ＩＤが含まれるかどうかを確認する（１８０４）。迂回要求返信信号リストに迂回要求返信信号の送信要求信号ＩＤが含まれるとき、受信した迂回要求返信信号は、すでに無線局１０９によって受信されているため、受信した迂回要求返信信号に対する処理を中止する（１８０５）。迂回要求返信信号リストに迂回要求返信信号の送信要求信号ＩＤが含まれないとき、無線局１０９の保持する迂回要求返信信号リストに、受信した迂回要求返信信号の送信要求信号ＩＤを書き加える（１８０６）。次に、受信した迂回要求返信信号中の発信無線局ＩＤが、自無線局即ち無線局１０９の無線局ＩＤと一致するかどうかを確認する（１８０７）。受信した迂回要求返信信号中の発信無線局ＩＤが、自無線局の無線局ＩＤと一致するとき、即ち迂回経路が構築された旨を伝える信号が、送信要求を発した無線局に到達したとき、迂回経路を用いたデータの送信を開始する（１８０８）。受信した迂回要求返信信号中の発信無線局ＩＤが、自無線局の無線局ＩＤと一致しないとき、無線局１０９は、受信した迂回要求返信信号をそのまま送信する（１８０９）。さらに次の迂回経路の構築も同様の処理を繰り返すことによって行われる。上記により複数の経路を送信局は知ることができる。これにより送信局は、情報パケットを複数の経路に対し送信する。
【００３８】
データ送信時に、宛先無線局が複数の経路から同一のデータ信号を複数受信するが、データ信号の到着時刻によって２つ目以降の信号を破棄する処理等を行うことによって、１つのデータのみを選択する。
【００３９】
また、本発明では、迂回経路構築のための探索を行うとき、１本目の経路で中継する無線局の数を参考にして、一定の数以上の無線局を中継する経路を探索しないようにすることにより、経路探索の効率化を図ることもできる。
【００４０】
無線回線によって情報を伝達し、直接電波の届かない無線局間の信号送受を可能とするように無線局が中継機能を有する無線パケットネットワークでは、データ送信時に経路の中継無線局として使用する無線局が、移動や電源の切断によって、経路の途中で切断されるときがある。経路切断時の再構築の手法は、使用する経路が切断されたことを、経路として使用することのできなくなった無線局の直前の無線局が認識して、経路切断の情報を発信無線局まで知らせて経路を再構築する方法や、直前の無線局が宛先無線局まで別の経路を構築して、構築した経路を発信無線局に知らせて、データの送信を開始する方法等があるが、本発明では、従来技術のいずれかの手法を用いて切断した経路の再構築を行い、経路を再構築している間、切断していない経路はその間もデータの送信を続けることができる。
【００４１】
また、各無線局は中継無線局として使用されるときに、自局で受信されるトラヒック量およびトラヒックの変動量、また送信されるトラヒック量及びトラヒックの変動量を観測して、パケット伝送する際に観測したトラヒック情報を中継するパケットに追加するなどして、無線局Ｃで観測されたトラヒック情報がネットワークで規定した一定量を超えている場合、受信局である無線局Ｂは、無線局Ｃでトラヒックの混雑が起こっていることや、トラヒックの混雑が予想されることを認識し、無線局Ａに対して返信を行う際に別の経路を構築する要求を示す識別子を付加する等をすることで、無線局Ａは経路が切断されたときと同様に経路の再構築を行うこともできる。
【００４２】
【発明の効果】
以上、説明したように、本発明の無線パケットの中継経路構築方法によれば、複数の経路が構築されることにより、一方の経路が切断された場合も他の経路でデータを送信することが可能なので、到着時間のゆらぎを抑えるという効果を有する。本発明は、音声、動画等のストリームデータのようなリアルタイム性を要求するアプリケーションを用いる場合、宛先無線局にできるだけ等しい間隔でデータを到着させることができる。
【００４３】
また、本発明によれば、トラヒック情報を用いれば、トラヒックの集中を回避する経路構築も可能になり、無線回線の回線使用効率が向上する効果が生まれる。また、無線通信の一つの無線局に対するアクセス制御は、混んでいる状態の場合に、リンクが確立するまで一定時間以上に待たされることによって経路の切断と判断することになり、データを送信する時の遅延につながることから、トラヒックの分散を行い混雑を軽減することは、遅延の低減にも効果がある。
【００４４】
また、本発明によれば、主経路を構築後、主経路を考慮に入れた迂回経路の構築を行うために、主経路とできるだけ相関のない経路を構築できる。しかも、迂回経路の構築中は、主経路でデータの送信を開始しているためにデータ送信開始までの時間も１本の経路を構築する場合と同じである。
【００４５】
更に、本発明によれば、発信無線局は、迂回経路のトラヒック量等の観測情報を得ることができるので、主経路から迂回経路への経路切替の時期を判断することもできる。
【図面の簡単な説明】
【図１】ネットワーク構成図である。
【図２】従来技術による信号Ｃの信号伝達経路の説明図である。
【図３】従来技術による送信要求信号のフレーム構成図である。
【図４】従来技術による送信要求信号リストの説明図である。
【図５】従来技術による送信要求信号受信時の無線局の処理のフローチャートである。
【図６】従来技術による要求返信信号リストの説明図である。
【図７】従来技術による要求返信信号のフレーム構成図である。
【図８】従来技術による要求返信信号受信時の無線局の処理のフローチャートである。
【図９】本発明による通信可能無線局信号のフレーム構成図である。
【図１０】本発明による通信可能無線局リストの説明図である。
【図１１】本発明による迂回経路構築開始の処理のフローチャートである。
【図１２】本発明による迂回送信要求信号リストの説明図である。
【図１３】本発明による重複する無線リンクの存在するネットワーク構成図である。
【図１４】本発明による迂回送信要求信号のフレーム構成図である。
【図１５】本発明による迂回送信要求信号を受信した無線局の処理のフローチャートである。
【図１６】本発明による迂回要求返信信号リストの説明図である。
【図１７】本発明による迂回要求返信信号のフレーム構成図である。
【図１８】本発明による迂回要求返信信号受信時の無線局の処理のフローチャートである。
【符号の説明】
１０１〜１０９、１３０１〜１３１０無線局
３０１信号ヘッダ（送信要求）
３０２、７０２、１４０３、１７０２送信要求信号ＩＤ
３０３、７０３、１４０４、１７０３発信無線局ＩＤ
３０４、７０４、１４０５、１７０４宛先無線局ＩＤ
３０５、７０５、１４０６、１７０５中継無線局ＩＤ
４０１、６０１、１２０１、１６０１送信要求信号ＩＤフィールド
５０１送信要求信号受信部
５０２送信要求信号受信状況判断部
５０３送信要求信号送信中止部
５０４送信要求信号リスト訂正部
５０５、１５０８宛先無線局判断部
５０６送信要求信号返信処理部
５０７送信要求信号訂正部
５０８送信要求信号送信部
７０１信号ヘッダ（要求返信）
８０１要求返信信号受信部
８０２中継無線局使用判断部
８０３、８０５要求返信信号送信中止部
８０４要求返信信号受信状況判断部
８０６要求返信信号リスト訂正部
８０７、１８０７発信無線局判断部
８０８経路データ送信部及び迂回経路構築処理部
８０９要求返信信号送信部
９０１信号ヘッダ（通信可能無線局）
９０２通信可能無線局ＩＤ
１００１通信可能無線局ＩＤフィールド
１１０１、１５０７迂回送信要求信号リスト訂正部
１１０２、１５１０通信可能無線局リスト参照判断部
１１０３、１１０４、１５１１、１５１２、１５１３迂回送信要求信号生成部
１１０５、１５１４迂回送信要求信号送信部
１４０１信号ヘッダ（迂回送信要求）
１４０２重複フラグ
１４０７、１７０６迂回中継無線局ＩＤ
１５０１迂回送信要求信号受信部
１５０２第２送信要求信号受信状況判断部
１５０３、１５０６迂回送信要求信号送信中止部
１５０４リンク重複判断部
１５０５重複フラグ参照部
１５０９迂回送信要求信号返信処理部
１７０１信号ヘッダ（迂回要求返信）
１８０１迂回要求返信信号受信部
１８０２迂回中継無線局使用判断部
１８０３、１８０５迂回要求返信信号送信中止部
１８０４迂回要求返信信号受信状況判断部
１８０６迂回要求返信信号リスト訂正部
１８０８迂回経路データ送信部
１８０９迂回要求返信信号送信部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wireless packet network in which a wireless station has a relay function so that information is transmitted through a wireless line and signals can be transmitted and received between wireless stations that do not directly reach radio waves. In particular, the present invention relates to a method of selecting a route when transmitting and receiving signals between radio stations to which radio waves do not directly reach.
[0002]
[Prior art]
FIGS. 1, 2 and 3 show a conventional route selection in a wireless packet network in which a wireless station has a relay function so that information is transmitted through a wireless line and signals can be transmitted and received between wireless stations to which radio waves do not directly reach. Examples of methods ("The Dynamic Source Routing Protocol for Mobile Ad Hoc Networks." The reference numerals in FIG. 2 correspond to the reference numerals of the wireless station in FIG. 1, and assume that the wireless station 101 transmits a packet to the wireless station 107.
[0003]
When a transmission request is generated in the wireless station 101, a transmission request signal indicating that a data transmission request has been generated is generated and transmitted to the wireless stations (102, 104, 108) capable of directly communicating with the wireless station 101. Send.
[0004]
FIG. 3 is a diagram illustrating a frame configuration of the transmission request signal. The transmission request signal is a signal header (301) indicating that it is a transmission request signal, a transmission request signal ID (302) for identifying the transmission request signal, and an originating wireless station indicating the wireless station ID of the wireless station 101. An ID (303), a destination wireless station ID (304) indicating the wireless station ID of the wireless station 107, and a relay wireless station ID (305) indicating a wireless station used as a relay wireless station. The relay wireless station IDs are added by the number of relayed wireless stations in the processing of the relay wireless station when constructing a route. The wireless station 101 adds a transmission request signal ID indicating the ID of the generated transmission request to the transmission request signal list held by the wireless station 101.
[0005]
FIG. 4 is an explanatory diagram of a transmission request signal list. This is a list for determining whether or not the transmission request signal received by each wireless station has already been processed by the wireless station. The transmission request signal ID of the transmission request signal processed by each wireless station ( 401) is written.
[0006]
Next, the processing of the wireless station that has received the transmission request signal will be described.
[0007]
FIG. 5 is a flowchart of the processing of the wireless station that has received the transmission request signal. The wireless stations 102, 104, and 108 capable of directly communicating with the wireless station 101 receive the transmission request signal transmitted by the wireless station 101 (501). The wireless station 102 that has received the transmission request signal from the wireless station 101 refers to the transmission request signal list held by the wireless station 102 and confirms that there is no received transmission request signal from the wireless station 101 in the transmission request signal list. (502). The confirmation that there is no transmission request signal is to confirm that the transmission request signal ID included in the received transmission request signal from the wireless station 101 is not included in the transmission request signal list held by the wireless station 102. Done by When the transmission request signal from the wireless station 101 is included in the transmission request signal list of the wireless station 102, the wireless station 102 has already received the transmission request signal from the wireless station 101, so that other wireless The transmission of the transmission request signal to the station is stopped (503). When the wireless station 102 confirms that the transmission request signal from the wireless station 101 is not included in the transmission request signal list, the wireless station 102 transmits the transmission request signal to the transmission request signal list held by the wireless station 102 similarly to the processing performed by the wireless station 101. A request signal ID is added (504). Next, the wireless station 102 compares the destination wireless station ID in the received transmission request signal with the wireless station ID of the wireless station 102 (505). When the destination wireless station ID and the wireless station ID of the wireless station 102 match, it is determined that the wireless station 102 is the destination wireless station for the transmission request, and a reply process for a transmission request signal described later is performed (506). On the other hand, when the destination wireless station ID does not match the wireless station ID of the wireless station 102, the wireless station 102 is added to the end of the transmission request signal received from the wireless station 101 to indicate that the wireless station 102 is used as the relay wireless station. Is added as the relay wireless station ID (507), and a transmission request signal is transmitted (508). The wireless stations 104 and 108 that have received the transmission request signal from the wireless station 101 perform the same operation as the wireless station 102. Each wireless station maintains a transmission request signal list and checks whether the received transmission request signal is the same as that received in the past, thereby enabling the wireless station that has received the transmission request signal once to perform the overlapping processing and the transmission request signal. This prevents signals from being transferred indefinitely between the same wireless stations in a loop.
[0008]
Next, a reply process to the transmission request signal will be described. In FIG. 1, the wireless station 107 that has received the transmission request signal has the same wireless station ID as the destination wireless station ID included in the transmission request signal in the above processing example. When the transmission request signal is found to be the destination wireless station, the column of the relay wireless station ID in the transmission request signal received by the wireless station 107 indicates that the destination wireless station 107 is the destination wireless station from the wireless station 101 that issued the transmission request. It becomes a relay route to. Among the transmission request signals having the same transmission request signal ID, a column of relay wireless station IDs in the transmission request signal arriving at the destination wireless station earliest is selected as the shortest path to the destination wireless station.
[0009]
Here, it is assumed that the route of wireless station 101-wireless station 102-wireless station 103-wireless station 107 has been selected. The reply process for the transmission request signal performed by the wireless station 107 is performed in the following procedure. First, the received transmission request signal ID is added to the request response signal list held by the wireless station 107. Next, a request reply signal is created and transmitted to a wireless station capable of direct communication with the wireless station 107.
[0010]
FIG. 6 is a request reply signal list. The transmission request signal ID (601) in the transmission request signal received by each wireless station is written in the request reply signal list.
[0011]
FIG. 7 is a diagram illustrating the frame structure of the request reply signal. The request reply signal is a signal header (701) indicating that it is a request reply signal, a transmission request ID (702) of the received transmission request signal, an originating wireless station ID (703) of the received transmission request signal, and The transmission request signal includes a destination wireless station ID (704) and a sequence of relay wireless station IDs in the received transmission request signal (705).
[0012]
Next, processing of the wireless station that has received the request reply signal will be described.
[0013]
FIG. 8 is a flowchart of the processing of the wireless station that has received the request reply signal. According to FIG. 1, the request reply signal transmitted by the wireless station 107 is received by the wireless stations 103, 106, and 109 with which the wireless station 107 can directly communicate (801). The wireless station 103 that has received the request reply signal checks whether the wireless station ID of the wireless station 103 itself, that is, the wireless station 103, is included in the column of relay wireless station IDs in the received request reply signal (802). When the wireless station ID of the own wireless station is not included in the column of the relay wireless station ID in the received request reply signal, it indicates that the own wireless station is not used as a relay wireless station on the route, and The processing for the request reply signal is stopped (803). When the wireless station ID of the own wireless station is included in the column of the relay wireless station ID in the received request reply signal, the following processing is performed. That is, it is confirmed whether the transmission request signal ID of the received request reply signal is included in the request reply signal list held by the wireless station 103 (804). When the request reply signal list includes the transmission request signal ID of the request reply signal, the received request reply signal has already been received by the wireless station 103, so that the processing for the received request reply signal is stopped (805). When the request reply signal list does not include the transmission request signal ID of the request reply signal, the transmission request signal ID of the received request reply signal is added to the request reply signal list held by the wireless station 103 (806). Next, it is confirmed whether or not the transmitting wireless station ID in the received request reply signal matches the wireless station ID of the wireless station 103 (807). When the originating wireless station ID in the received request reply signal matches the wireless station ID of the own wireless station, that is, when a signal indicating that a route has been established to the wireless station that has issued the transmission request has arrived, The data transmission process using the route is performed (808). When the transmitting wireless station ID in the received request reply signal does not match the wireless station ID of the own wireless station, the wireless station 103 transmits the received request reply signal as it is (809). That is, the wireless station 107 transmits a request reply signal to the wireless station 101 by following the path reverse to the path information included in the arrived transmission request signal.
[0014]
[Problems to be solved by the invention]
Originally, the quality of a wireless line changes depending on the situation at that time. For this reason, communication may not be possible even after the communication path has been established. In the conventional relay route construction method, once a communication route is selected, the route is used until a line disconnection of the route is detected. The disconnection of the line is detected by confirming that the transmitting side wireless station in the disconnected wireless section does not return a reception confirmation signal from the receiving side wireless station for a certain period of time or more, and that wireless station notifies the wireless station A. However, there is a drawback in that the signal arrival time at the wireless station B fluctuates in delay due to the time required to detect the path disconnection and the time required to reconstruct the path. If the delay fluctuation is large, such a wireless packet network cannot be used to transfer a signal such as voice that requires real-time performance.
[0015]
In addition, since the same route is continuously used until the disconnection of the line is detected, the transfer delay time at the relay wireless station or the like fluctuates due to traffic fluctuation, etc., so that the selected route is no longer the shortest route. There was a problem that the efficiency of the entire network was reduced.
[0016]
The conventional relay route construction method is a method for constructing one optimal main route. Therefore, if a plurality of detour routes are to be constructed at the same time, the process for constructing the route is repeatedly performed in each wireless station, and there is a problem that the route construction does not converge. Further, even if an attempt is made to construct an alternative route after constructing one main route, a plurality of relay routes cannot be constructed because the same route as the already constructed main route is constructed. Furthermore, when starting to construct a plurality of routes at the same time, it has been difficult to construct a route that takes into account the status of each other between the main route and the detour route.
[0017]
[Means for Solving the Problems]
Therefore, a method for constructing a relay route of a wireless packet according to the present invention is a wireless network including a plurality of wireless stations having a function of relaying a packet signal, wherein a transmission request signal includes a transmission request signal ID, an originating wireless station, The transmission request signal list includes an ID, a destination radio station ID, and a relay radio station ID sequence that is additionally stored each time a radio station is relayed. And the wireless station that has received the transmission request signal, if the transmission request signal list includes the transmission request signal ID of the transmission request signal, ends the first processing for the transmission request signal. A second step of adding the transmission request signal ID to the transmission request signal list if not, and a second step of performing a reply process if the wireless station ID of the wireless station matches the destination wireless station ID. Three A fourth step of adding the wireless station ID to the transmission request signal as a relay wireless station ID, and a fifth step of transmitting the transmission request signal to a wireless station with which the wireless station can directly communicate. And a relay route construction method for constructing a main communication route having the steps of: constructing a main communication route and then constructing another bypass communication route. ID, originating wireless station ID, destination wireless station ID, a relay wireless station ID string of the already established main communication path, and a detour relay wireless station ID string additionally stored every time a wireless station is relayed. The wireless station has a bypass transmission request signal list storing the already processed bypass transmission request signal ID and a communicable wireless station list storing the communicable wireless stations. Received the If the detour transmission request signal list includes the detour transmission request signal ID of the detour transmission request signal, the line station performs a sixth step of terminating the processing for the detour transmission request signal, In the relay radio station ID column of the communication path, if the radio station ID of the radio station exists following the last detour relay radio station ID in the detour relay radio station ID sequence and the duplication flag is not set, A seventh step of ending the processing for the detour transmission request signal, and, in the relay radio station ID sequence, the radio station ID of the radio station following the last detour relay radio station ID in the detour relay radio station ID sequence. Does not exist, or In the relay radio station ID sequence, a radio station ID of the radio station exists following the last detour relay radio station ID in the detour relay radio station ID sequence, and The eighth step of adding the detour transmission request signal ID to the detour transmission request signal list when the duplication flag is set, and a reply process if the radio station ID of the radio station matches the destination radio station ID A ninth step of terminating the processing for the detour transmission request signal, and if not, the radio station that transmitted the detour transmission request signal is included in the communicable radio station list of the radio station, and the main communication A duplicate flag is set when there is no radio station other than the radio station used in the route; otherwise, a duplicate flag is not set, and the radio station ID is included in the detour transmission request signal. Is added as a detour relay radio station ID, and a twelfth step of transmitting a detour transmission request signal to a radio station with which the radio station can directly communicate.
[0018]
According to another embodiment of the present invention, the communicable radio station list includes a communicable signal that the radio station receives intermittently transmitted by another radio station at regular intervals, and the communication of the communicable signal is performed. A possible wireless station ID and a reception time thereof are recorded. If a communicable signal corresponding to the communicable wireless station ID is not received within a predetermined monitoring cycle time, the communicable wireless station ID is stored. It is also preferable to delete from the communicable wireless station list.
[0019]
According to another embodiment of the present invention, the wireless station observes the amount of received traffic, the amount of transmitted traffic, the amount of received traffic variation and / or the amount of transmitted traffic variation in the wireless station, and detours the observation information. It is also preferable that the transmission request signal is additionally stored every time a wireless station is relayed.
[0020]
Further, according to another embodiment of the present invention, in the return process in the ninth step, the sequence of the observation information in the detour transmission request signal is directly returned, and the originating wireless station is notified of the sequence of the observation information. It is also preferable.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Referring to FIG. 1, a route construction method according to the present invention will be described. A description will be given of an example in which a request for data transmission to the wireless station 107 to which the wireless station 101 cannot perform direct communication occurs, and data transmission is performed by constructing two routes for one transmission request. In this embodiment, the case where the number of routes is two is shown, but the number of routes to be constructed in the present invention is plural and is not limited to two.
[0022]
FIG. 9 is a diagram illustrating a frame configuration of a communicable wireless station signal. In the present invention, each wireless station intermittently transmits a communicable wireless station signal to make a wireless station capable of directly communicating aware of its presence. The communicable radio station signal includes a signal header (901) indicating a communicable radio station signal and a communicable radio station ID (902) indicating a radio station ID of a radio station that has issued the communicable radio station signal. . The radio station that has received the communicable radio station signal is based on the communicable radio station ID in the communicable radio station signal and within a range in which the communicable radio station signal can be directly communicated by the communicable radio station signal. Communicable radio station ID included in the communicable radio station signal received in the communicable radio station list held by the radio station that has received the communicable radio station signal, The time when the possible non-selection channel signal is received is added.
[0023]
FIG. 10 is an explanatory diagram of a communicable wireless station list. The communicable wireless station list is a set of records including fields of a communicable wireless station ID and a reception time (1001). In this way, the communicable wireless station list is created by writing the received wireless station ID. However, if a wireless station that has been able to be received has moved away from the communicable range due to the movement, the corresponding wireless station list is created. Communicable wireless station signals from the wireless station to be communicated cannot be received. In this case, a radio station monitoring cycle longer than the intermittent cycle of the communicable radio station signal is provided, and the current time is compared with the reception time of the communicable radio station list. By deleting the station ID, it is possible to create a wirelessly communicable wireless station list dynamically with respect to movement of the wireless station. Of course, in this case, each time a communicable wireless station signal is received, the reception time of the list is updated. Alternatively, if the communication wireless station list is a set of only the communicable wireless station IDs shown in FIG. 10 and a timer for the wireless station monitoring cycle is provided for each wireless station ID and a communicable wireless station signal is received, The timer may be reset, and the corresponding wireless station ID may be deleted when the timer times out. Thus, in response to the dynamic change of the network configuration due to the movement of the wireless station, each wireless station transmits and receives a communicable unselected signal, and autonomously confirms the wireless station existing in the communicable area. Thus, an ad hoc network is established as a whole.
[0024]
First, one route (route X) from the wireless station 101 to the wireless station 107 is constructed. When the wireless station 101 receives the request reply signal indicating that the route X has been established, the wireless station 101 starts transmitting data to the wireless station 107 using the route X, and at the same time, starts the detour route construction.
[0025]
FIG. 11 is a flowchart of a process of starting detour route construction. In FIG. 1, when the request reply signal of the route X is received by the wireless station 101, that is, when the request reply signal of the route X arrives at the wireless station that has issued the transmission request, the request reply signal of the route X The transmission request signal ID in the signal is added (1101).
[0026]
FIG. 12 is an explanatory diagram of a detour transmission request signal list. The detour transmission request signal list is a set of records including the field of the transmission request signal ID (1201) in the request return signal of the route X. Next, the number of wireless stations included in the communicable wireless station list held by the wireless station 101 is confirmed (1102). When the number of wireless stations included in the communicable wireless station list held by the wireless station 101 is 1, that is, when the wireless station 101 can directly communicate with only one wireless station, a detour transmission request signal transmitted by the wireless station 101 (1103). When the number of wireless stations included in the communicable wireless station list held by the wireless station 101 is greater than 1, that is, when there are a plurality of wireless stations with which the wireless station 101 can directly communicate, a detour transmission request signal transmitted by the wireless station 101 Is not set (1104). The duplication flag indicates that the radio link between the radio stations included in the route X and the radio link between the radio stations included in the detour route are used when the detour route is constructed. This is for determining whether or not to permit. The determination of permission is made on the side of the wireless station that has received the bypass transmission request signal. When the number of wireless stations included in the communicable wireless station list held by the wireless station 101 is one, that is, when the wireless station 101 can directly communicate with only one wireless station, the wireless station 101 and the wireless station 101 directly communicate with each other. The wireless link between the only wireless station within the communication range is used in the path X, but other wireless stations within the direct communication range of the wireless station 101 and the wireless station 101 Since there is no wireless link between the wireless station 101 and the detour path, the wireless link between the wireless station 101 overlapping the route X and the only wireless station within the range where the wireless station 101 can directly communicate is used. I do.
[0027]
FIG. 13 is a network configuration diagram in which it is necessary to use a wireless link that overlaps between the route X and the detour route. In FIG. 13, when a transmission request is issued from the wireless station 1301 to the wireless station 1310, a wireless link between the wireless station 1301 and the wireless station 1302, a wireless link between the wireless station 1305 and the wireless station 1306, The wireless link between the station 1309 and the wireless station 1310 is a wireless link that is used redundantly in the route X and the detour route.
[0028]
FIG. 14 is a diagram illustrating a frame configuration of a detour transmission request signal. The detour transmission request signal includes a signal header (1401) indicating that the signal to be transmitted is a detour transmission request signal, and an overlap between the radio link between the radio stations on the route X and the radio link between the radio stations on the detour route. The duplication flag (1402) used to determine whether or not to permit, the transmission request signal ID (1403) included in the received request reply signal, and the transmission wireless station ID (1404) indicating the wireless station ID of the wireless station 101 ), A destination wireless station ID (1405) indicating the wireless station ID of the wireless station 107 that is the destination wireless station, a relay wireless station ID column (1406) in the request reply signal of the route X, and a detour route. And a detour relay wireless station ID (1407) indicating the wireless station. The wireless station 101 transmits the generated detour transmission request signal (1105).
[0029]
Although not shown in FIG. 14, observation information such as traffic measured at each relay wireless station may be additionally stored in the detour transmission request signal every time the wireless station is relayed. This observation information includes the amount of received traffic, the amount of transmitted traffic, the amount of received traffic variation, and / or the amount of transmitted traffic variation in the wireless station. Also, as for these pieces of observation information, the sequence of the observation information in the detour transmission request signal can be returned as it is by the return process in the destination wireless station, and the originating wireless station can be notified of the sequence of the observation information. As a result, a route can be selected according to a change in traffic. In particular, it is effective in a system in which the traffic fluctuation amount of the entire network is large.
[0030]
Next, the processing of the wireless station that has received the bypass transmission request signal will be described.
[0031]
FIG. 15 is a flowchart of the process of the wireless station that has received the bypass transmission request signal. According to FIG. 1, the detour transmission request signal transmitted by the wireless station 101 is received by the wireless station 102, the wireless station 104, and the wireless station 108 existing within a range where the wireless station 101 can directly communicate (1501). The wireless station 108 that has received the detour transmission request signal confirms whether the detour transmission request signal list held by the wireless station 108 includes the transmission request signal ID in the received detour transmission request signal (1502). When the detour transmission request signal list held by the wireless station 108 includes the transmission request signal ID in the received detour transmission request signal, the radio station 108 performs the detour transmission having the same transmission request signal ID as the received detour transmission request signal. Since it indicates that the process is being performed on the request signal, the process on the received detour transmission request signal is stopped (1503). When the detour transmission request signal list held by the wireless station 108 does not include the transmission request signal ID in the received detour transmission request signal, the radio station ID at the end of the detour relay radio station ID in the received detour transmission request signal And confirms whether or not the wireless link with the wireless station ID of the wireless station 108 overlaps with any wireless link in the column of the relay wireless station ID of the path X in the received detour transmission request signal. (1504). The radio link between the wireless station ID at the end of the detour relay radio station ID in the received detour transmission request signal and the radio station ID of the own radio station is the same as the relay radio station ID of the route X in the received detour transmission request signal. When overlapping with any of the wireless links in the column, the wireless link used in path X and the wireless link between the wireless station that transmitted the alternate transmission request signal to wireless station 108 and wireless station 108 are: This indicates that they are duplicated, and it is checked whether the duplicate flag is set in the received detour transmission request signal (1505). When the duplicate flag in the received detour transmission request signal is not set, the radio station that has transmitted the detour transmission request signal to the radio station 108 can establish a radio link with a radio station other than the radio station 108. Therefore, the wireless station 108 stops the processing for the received detour transmission request signal (1506). When the duplication flag in the received detour transmission request signal is set, the wireless station that transmitted the detour transmission request signal to the wireless station 108 cannot establish a wireless link with a wireless station other than the wireless station 108. Therefore, the wireless station 108 continues to process the received detour transmission request signal in order to allow the wireless link overlapping the route X to be used in the detour route. Also, the radio link between the wireless station ID at the end of the detour relay station ID in the received detour transmission request signal and the radio station ID of the own radio station is determined by the relay radio station on the path X in the received detour transmission request signal. Even when the wireless station 108 does not overlap with any of the wireless links in the ID column, the wireless station 108 continues to process the received alternate transmission request signal. When the process is continued, the transmission request signal ID in the received detour transmission request signal is added to the detour transmission request signal list held by the wireless station 108 (1507). Next, it is confirmed whether or not the destination wireless station ID in the received detour transmission request signal matches the wireless station ID of the wireless station 108 (1508). If the destination wireless station ID in the received detour transmission request signal matches the wireless station ID of the own wireless station, the own wireless station is the destination wireless station, and a reply process for the detour path construction described later is performed (1509). When the destination wireless station ID in the received detour transmission request signal does not match the wireless station ID of the own wireless station, that is, when the own wireless station is not the destination for the transmission request, the communicable wireless station list held by the wireless station 108 is stored. By referring to the number, the number of wireless stations existing within a range where the wireless station 108 can directly communicate is checked (1510). When the wireless station 108 transmits the alternate transmission request signal, the wireless station that can receive the signal establishes the wireless station that has transmitted the alternate transmission request signal to the wireless station 108 or a wireless link used in the first route. When there is only a wireless station to perform the detour transmission request signal transmitted by the wireless station 108, an overlap flag is set (1511). At this time, the wireless station 108 refers to the column of the relay wireless station ID of the route X in the received detour transmission request signal, and determines whether to set an overlap flag. The wireless station ID in the communicable wireless station list held by the wireless station 108 includes the wireless station ID of the wireless station that transmitted the bypass transmission request signal to the wireless station 108 and the relay wireless station of the route X in the bypass transmission request signal. When the wireless station 108 further includes the wireless station 108 and the wireless station IDs other than the wireless station IDs of the two wireless stations before and after the wireless station 108, that is, the wireless station 108 When transmission can be performed using a link, the duplicate flag of the detour transmission request signal transmitted by the wireless station 108 is not set (1512). Next, the wireless station 108 adds the wireless station ID of its own wireless station, that is, the wireless station 108, to the alternate relay wireless station ID in the alternate transmission request signal (1513), and transmits the alternate transmission request signal (1514). The wireless stations 102 and 104 that have received the detour transmission request signal from the wireless station 101 perform the same operation as the wireless station 108, as in the case of constructing the route X. Each radio station maintains a list of detour transmission request signals and checks whether the received detour transmission request signal is the same as that received in the past, so that the radio station that has once received the detour transmission request signal can The present invention prevents the detour transmission request signal from being infinitely looped and transferred between the same wireless stations, thereby reducing network traffic.
[0032]
Next, a reply process to the bypass transmission request signal will be described. In FIG. 1, as in the case of establishing the route X, the wireless station 107 that has received the bypass transmission request signal determines the wireless station ID of its own wireless station and the destination included in the bypass transmission request signal in the bypass route configuration processing of the above example. When the wireless station IDs match, that is, when it is determined that the wireless station 107 is the destination wireless station for the transmission request in the above example, the column of the alternate relay wireless station ID in the alternate transmission request signal received by the wireless station 107 includes This is a detour path from the wireless station 101 that issued the request to the wireless station 107 that is the destination wireless station. Among the detour transmission request signals having the same transmission request signal ID, the column of the detour relay radio station ID in the detour transmission request signal arriving at the destination wireless station earliest is selected as the detour path of the shortest route to the destination radio station. You. Here, it is assumed that the route of wireless station 101-wireless station 108-wireless station 109-wireless station 107 has been selected as a bypass route. The reply process for the detour transmission request signal performed by the wireless station 107 is performed in the following procedure. First, the received detour transmission request signal ID is added to the detour request reply signal list held by the wireless station 107.
[0033]
FIG. 16 is an explanatory diagram of a detour request reply signal list. The detour request reply signal list is a set of records having a transmission request signal ID (1601) in the received detour request reply signal as a field.
[0034]
Next, a detour request reply signal is created.
[0035]
FIG. 17 is a frame configuration diagram of a detour request reply signal. The detour request reply signal is a signal header (1701) indicating that it is a detour request reply signal, a transmission request signal ID (1702) in the received detour transmission request signal, and a transmitting wireless station in the received detour transmission request signal. ID (1703), the destination wireless station ID (1704) in the received detour transmission request signal, the column (1705) of the relay wireless station ID of the path X in the received detour transmission request signal, and the received detour transmission request The radio station 107 is composed of a column of detour relay radio station IDs in the signal (1706), and the radio station 107 transmits the generated detour request reply signal.
[0036]
Next, the processing of the wireless station that has received the detour request reply signal will be described.
[0037]
FIG. 18 is a flowchart of the process of the wireless station that has received the detour request reply signal. According to FIG. 1, the detour request reply signal transmitted by the wireless station 107 is received by the wireless station 103, the wireless station 106, and the wireless station 109 existing within a range where the wireless station 107 can directly communicate (1801). The wireless station 109 that has received the detour request reply signal checks whether or not the wireless station ID of its own wireless station, that is, the wireless station 109, is included in the detour relay wireless station ID in the received detour request reply signal (1802). When the wireless station ID of the own wireless station is not included in the alternate relay wireless station ID in the received alternate request reply signal, it indicates that the own wireless station is not used as the alternate wireless station on the alternate route. The processing for the detour request reply signal thus stopped is stopped (1803). When the wireless station ID of the own wireless station is included in the bypass relay wireless station ID in the received bypass request reply signal, the following processing is performed. That is, it is confirmed whether or not the transmission request signal ID of the received detour request reply signal is included in the detour request reply signal list held by the wireless station 109 (1804). When the transmission request signal ID of the detour request reply signal is included in the detour request reply signal list, the received detour request reply signal has already been received by the wireless station 109, so that the processing for the received detour request reply signal is stopped. (1805). When the transmission request signal ID of the detour request reply signal is not included in the detour request reply signal list, the transmission request signal ID of the received detour request reply signal is added to the detour request reply signal list held by the wireless station 109 (1806). ). Next, it is confirmed whether or not the transmitting wireless station ID in the received detour request reply signal matches the wireless station ID of the own wireless station, that is, the wireless station 109 (1807). When the originating wireless station ID in the received detour request reply signal matches the wireless station ID of the own wireless station, that is, when the signal indicating that the detour path has been established reaches the wireless station that issued the transmission request Then, transmission of data using the bypass route is started (1808). When the originating wireless station ID in the received detour request reply signal does not match the wireless station ID of the own radio station, the wireless station 109 transmits the received detour request reply signal as it is (1809). Further, the construction of the next detour route is performed by repeating the same processing. As described above, the transmitting station can know a plurality of routes. As a result, the transmitting station transmits information packets to a plurality of routes.
[0038]
At the time of data transmission, the destination wireless station receives a plurality of the same data signals from a plurality of paths, but selects only one data by performing processing such as discarding the second and subsequent signals according to the arrival time of the data signals. I do.
[0039]
Further, in the present invention, when performing a search for constructing a detour route, referring to the number of wireless stations relayed on the first route, a search for a route relaying a certain number or more of wireless stations is prevented. Thereby, the efficiency of the route search can be improved.
[0040]
In a wireless packet network where a wireless station has a relay function so that information can be transmitted over a wireless line and signals can be transmitted and received between wireless stations that do not directly reach the radio station, a wireless station used as a relay wireless station on a route when transmitting data May be disconnected in the middle of the route due to movement or power-off. The method of rebuilding at the time of route disconnection is that the wireless station immediately before the wireless station that can no longer be used as a route recognizes that the route to be used has been disconnected, and sends the route disconnection information to the originating wireless station. There is a method of notifying and rebuilding the route, a method of starting the data transmission by the immediately preceding wireless station constructing another route to the destination wireless station, informing the originating wireless station of the constructed route, According to the present invention, the route that has been disconnected is reconstructed by using any of the techniques of the related art, and while the route is being reconstructed, data transmission can be continued on the route that has not been disconnected.
[0041]
Also, when each wireless station is used as a relay wireless station, it observes the amount of traffic and the amount of change in traffic received by its own station, and the amount of traffic and the amount of change in traffic to be transmitted. When the traffic information observed at the wireless station C exceeds a certain amount specified by the network, for example, by adding the traffic information observed at the wireless station C to a relay packet, the wireless station B as the receiving station is And recognizes that traffic congestion is occurring or anticipated traffic congestion, and adds an identifier indicating a request for establishing another route when replying to the wireless station A. Thus, the wireless station A can reconstruct the route in the same manner as when the route is disconnected.
[0042]
【The invention's effect】
As described above, according to the wireless packet relay route construction method of the present invention, by constructing a plurality of routes, even if one route is disconnected, data can be transmitted on another route. Since it is possible, it has the effect of suppressing fluctuations in the arrival time. According to the present invention, when an application that requires real-time properties such as stream data such as audio data and moving image data is used, data can arrive at the destination wireless station at equal intervals as possible.
[0043]
Further, according to the present invention, by using the traffic information, it is possible to construct a route for avoiding the concentration of traffic, and the effect of improving the line use efficiency of the wireless line is produced. In addition, in the access control for one wireless station in wireless communication, in a congested state, it is determined that a route is disconnected by waiting for a certain time or more until a link is established, and when transmitting data, Therefore, distributing traffic to reduce congestion is also effective in reducing delay.
[0044]
Further, according to the present invention, after the main route is constructed, the detour route is constructed in consideration of the main route, so that a route having as little correlation as possible with the main route can be constructed. In addition, during the construction of the detour route, the data transmission is started on the main route, so that the time until the start of data transmission is the same as the case where one route is constructed.
[0045]
Furthermore, according to the present invention, the originating wireless station can obtain observation information such as the traffic amount of the detour route, so that it is possible to determine the timing of switching the route from the main route to the detour route.
[Brief description of the drawings]
FIG. 1 is a network configuration diagram.
FIG. 2 is an explanatory diagram of a signal transmission path of a signal C according to the related art.
FIG. 3 is a diagram illustrating a frame structure of a transmission request signal according to the related art.
FIG. 4 is an explanatory diagram of a transmission request signal list according to the related art.
FIG. 5 is a flowchart of a process performed by a wireless station when a transmission request signal is received according to the related art.
FIG. 6 is an explanatory diagram of a request reply signal list according to the related art.
FIG. 7 is a frame configuration diagram of a request reply signal according to the related art.
FIG. 8 is a flowchart of a process performed by a wireless station when receiving a request reply signal according to the related art.
FIG. 9 is a diagram illustrating a frame configuration of a communicable wireless station signal according to the present invention.
FIG. 10 is an explanatory diagram of a communicable wireless station list according to the present invention.
FIG. 11 is a flowchart of a process of starting detour route construction according to the present invention.
FIG. 12 is an explanatory diagram of a detour transmission request signal list according to the present invention.
FIG. 13 is a network configuration diagram in which overlapping wireless links exist according to the present invention.
FIG. 14 is a diagram illustrating a frame configuration of a detour transmission request signal according to the present invention.
FIG. 15 is a flowchart of processing of a wireless station that has received a bypass transmission request signal according to the present invention.
FIG. 16 is an explanatory diagram of a detour request reply signal list according to the present invention.
FIG. 17 is a frame configuration diagram of a detour request reply signal according to the present invention.
FIG. 18 is a flowchart of a process performed by a wireless station when a detour request reply signal is received according to the present invention.
[Explanation of symbols]
101-109, 1301-1310 radio stations
301 signal header (transmission request)
302, 702, 1403, 1702 Transmission request signal ID
303, 703, 1404, 1703 Calling station ID
304, 704, 1405, 1704 Destination wireless station ID
305, 705, 1406, 1705 Relay radio station ID
401, 601, 1201, 1601 Transmission request signal ID field
501 transmission request signal receiving unit
502 Transmission request signal reception status determination unit
503 Transmission request signal transmission suspension section
504 Transmission request signal list correction unit
505, 1508 Destination radio station judgment unit
506 Transmission request signal reply processing unit
507 Transmission request signal correction unit
508 Transmission request signal transmission unit
701 Signal header (request reply)
801 request reply signal receiving unit
802 relay wireless station use determination unit
803, 805 Request return signal transmission stop unit
804 Request reply signal reception status judgment unit
806 Request reply signal list correction unit
807, 1807 originating wireless station determination unit
808 Route data transmission unit and detour route construction processing unit
809 Request reply signal transmission unit
901 signal header (communicable radio station)
902 Communication available wireless station ID
1001 Communication available wireless station ID field
1101, 1507 Detour transmission request signal list correction unit
1102, 1510 communicable wireless station list reference determination unit
1103, 1104, 1511, 1512, 1513 Detour transmission request signal generator
1105, 1514 Detour transmission request signal transmission unit
1401 signal header (rerouting transmission request)
1402 Duplicate flag
1407, 1706 Detour relay wireless station ID
1501 detour transmission request signal receiving unit
1502 second transmission request signal reception status determination unit
1503, 1506 Detour transmission request signal transmission stop unit
1504 Link duplication judgment unit
1505 Duplication flag reference section
1509 Detour transmission request signal reply processing unit
1701 Signal header (return request return)
1801 detour request reply signal receiving unit
1802 detour relay wireless station use determination unit
1803, 1805 detour request reply signal transmission stop unit
1804 Detour request reply signal reception status determination unit
1806 Detour request reply signal list correction unit
1808 Detour route data transmission unit
1809 detour request reply signal transmission unit

Claims

A wireless network including a plurality of wireless stations having a function of relaying a packet signal,
The transmission request signal is composed of a transmission request signal ID, an originating wireless station ID, a destination wireless station ID, and a relay wireless station ID sequence that is additionally stored each time a wireless station is relayed. It has a transmission request signal list that stores the transmission request signal IDs already processed,
The radio station that has received the transmission request signal, if the transmission request signal list includes the transmission request signal ID of the transmission request signal, a first step of ending the processing for the transmission request signal; For example, a second step of adding the transmission request signal ID to the transmission request signal list, and a third step of performing a reply process if the wireless station ID of the wireless station matches the destination wireless station ID, Otherwise, there is a fourth step of adding the wireless station ID to the transmission request signal as a relay wireless station ID, and a fifth step of transmitting the transmission request signal to a wireless station with which the wireless station can directly communicate. In a method for constructing a relay route of a wireless packet for constructing a main communication route,
After constructing the main communication path, in order to construct another detour communication path,
The detour transmission request signal includes a duplication flag, a detour transmission request signal ID, an originating wireless station ID, a destination wireless station ID, a relay wireless station ID string of a main communication route already established, and a relay station. And a detour relay radio station ID string stored additionally to the radio station. The radio station has a detour transmission request signal list storing the processed detour transmission request signal ID and a communicable radio station storing communicable radio stations. A radio station list,
If the wireless station that has received the detour transmission request signal includes the detour transmission request signal ID of the detour transmission request signal in the detour transmission request signal list, a sixth step of ending the processing for the detour transmission request signal Otherwise, in the relay radio station ID column of the main communication path, the radio station ID of the radio station exists following the last detour relay radio station ID in the detour relay radio station ID column, and is duplicated. If the flag is not set, a seventh step of terminating the processing for the detour transmission request signal, and a step following the last detour relay station ID in the detour relay station ID string in the relay station ID string The wireless station ID of the wireless station does not exist, or the wireless station ID of the wireless station follows the last alternate relay wireless station ID in the alternate relay wireless station ID string in the relay wireless station ID string. exist, and duplicate flag is standing In this case, the eighth step of adding the detour transmission request signal ID to the detour transmission request signal list, and if the radio station ID of the radio station matches the destination radio station ID, a return process is performed to execute the detour. A ninth step of terminating the process for the transmission request signal, and if not, in the communicable radio station list of the radio station, A tenth stage in which a duplication flag is set when there is no radio station other than the current radio station, and in which a duplication flag is not set otherwise; A method for constructing a relay route for a wireless packet, comprising: an eleventh step of adding a station ID as a station ID; and a twelfth step of transmitting a bypass transmission request signal to a wireless station with which the wireless station can directly communicate.

The communicable wireless station list receives a communicable signal that the wireless station transmits intermittently by another wireless station at regular intervals, and records the communicable wireless station ID of the communicable signal and the reception time. Wherein, if a communicable signal corresponding to the communicable wireless station ID is not received during a predetermined monitoring cycle time, the communicable wireless station ID is deleted from the communicable wireless station list. The method of claim 1, wherein:

The wireless station monitors the amount of received traffic, the amount of transmitted traffic, the amount of received traffic variation and / or the amount of transmitted traffic variation in the wireless station, and relays the observation information to the wireless station in the detour transmission request signal. 3. The method according to claim 1, wherein the information is additionally stored every time.

4. The reply process in the ninth step, wherein the sequence of the observation information in the detour transmission request signal is returned as it is, and the originating wireless station is notified of the sequence of the observation information. the method of.