JP2004134961A - Communication method and communication equipment for wireless network - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication method and communication equipment wherein call origination can properly be restricted and the deterioration in the throughput of an entire wireless network can be prevented. <P>SOLUTION: In the wireless network wherein wireless stations perform wireless communication, the communication method includes the steps of: using a plurality of radiation patterns having different directivity characteristics of an array antenna whose directivity characteristics can be varied to receive wireless signals of a desired wave from a first wireless station respectively; obtaining a reception response vector r<SB>d</SB>of the desired wave and whose elements include the respective received signals and the same reference signal as a signal to be transmitted; using a plurality of the radiation patterns of the array antenna to receive wireless signals of an interference wave from a second wireless station respectively; obtaining the reception response vector r<SB>i</SB>of the interference wave whose elements are the respective received signals and the reference signal same as the signal to be transmitted, calculating a spatial correlation coefficient between the desired wave and the interference wave; and transmitting a transmission restriction request to the second wireless station when the spatial correlation coefficient calculated at the wireless communication with the first wireless station is a prescribed threshold value or over. <P>COPYRIGHT: (C)2004,JPO

Description

【００３７】
ここで、ｗ_ｍは等価重み係数（ウエイト）ベクトル（非特許文献２を参照）を表し、所望波及び干渉波のステアリングベクトルをそれぞれａ_ｄ及びａ_ｉと表記している。上付きのＨと＊は、それぞれエルミート転置と複素共役を表す。ｒ_ｄとｒ_ｉは、受信応答ベクトルｒに、それぞれ所望波と干渉波の受信応答ベクトルであることを示すために添字ｄとｉを付加して表記したものである。受信応答ベクトルｒ＝［ｒ_０，ｒ_１，…，ｒ_６］^Ｔは、受信信号系列ｙ_０（ｔ），ｙ_１（ｔ），…，ｙ_６（ｔ）と送信信号ｕ（ｔ）の複素共役との積を取り、その期待値（所定の期間における時間平均値）から演算される。
【００３８】
【数２】
ｒ_ｍ＝Ｅ［ｙ_ｍ（ｔ）ｕ（ｔ）^＊］
ｍ＝０，１，…，６
【００３９】
ここで、送信信号ｕ（ｔ）は、発信元の無線局１から送信される信号と同一の信号を、当該受信側の無線局１の学習シーケンス信号発生器１５２において発生させることによって得られる基準信号である。
【００４０】
数１から分かるように、エスパアンテナ装置１０１で取得される各無線局１の空間相関値は、ステアリングベクトルａ（θ）及び可変容量ダイオード１２−１乃至１２−６のリアクタンス値の関数となる。従って、各無線局１の空間相関値を干渉波抑圧可否の判定に用いる際には、図５のリアクタンス値テーブルのようなリアクタンス値の組を明確にする必要がある。また、数１の空間相関値は規格化して絶対値を取っているため、伝搬路特性ｈ（ｔ）は空間相関値に含まれない。
【００４１】
図５のリアクタンス値テーブルの０番目と（２ｍ−１）番目のアンテナパターン（ｍ＝１，…，６）にて受信した受信信号ｙ_ｍ（ｔ）は、エスパアンテナ装置１０１のステアリングベクトルをａ（θ）、伝搬路特性ｈ（ｔ）、発信元の無線局１からの送信信号をｕ（ｔ）及び熱雑音成分をｎ（ｔ）とすると、次式のように表される。
【００４２】
【数３】

【００４３】
ここで、ｈ（ｔ）は送受信アンテナの指向性利得Ｇ_ｔ、波数ｋ、伝搬経路長ｄを用いて次式のように表される、インパルス応答の複素振幅である。
【００４４】
【数４】

【００４５】
以上説明したように計算された空間相関値は、データベースメモリ１５４中の空間相関テーブルに記録される。数１から明らかなように、空間相関テーブルを取得するためには２つ以上の隣接無線局からの受信信号系列が必要である。
【００４６】
図８は、図１の無線局１−Ａにおけるエスパアンテナ装置１０１の指向性パターンの実施例を示す指向特性図である。この図に示された例では、無線局１−Ａの周囲に無線局１−Ｂ，１−Ｃ及び１−Ｄが位置している。無線局１−ＡがＳＩＮＲテーブルと空間相関テーブルの生成を開始することを示すＳＥＴＵＰ信号（図１０（ａ）を参照）を送信するときは、図５のリアクタンス値テーブルに従ってオムニパターンＯＰをエスパアンテナ装置１０１に設定する。ＳＥＴＵＰ信号に続くＲＱ（０）信号（図１０（ｂ）を参照）を送信するときは、方位角０度方向を向いたセクタパターンＳＰ（１）をエスパアンテナ装置１０１に設定し、ＲＱ（０）信号に続くＲＱ（３０）信号を送信するときは、３０度方向を向いたセクタパターンＳＰ（２）をエスパアンテナ装置１０１に設定し、以下同様に３３０度方向を向いたセクタパターンＳＰ（３３０）まで設定する。無線局１−Ａが他の無線局１からＲＥ信号（図１０（ｂ）を参照）を受信するとき、さらに、無線局１−Ａが他の無線局からＳＥＴＵＰ信号及びＲＱ（０）乃至ＲＱ（３３０）信号を受信するときとＲＥ信号を送信するときもまた、オムニパターンＯＰをエスパアンテナ装置１０１に設定する。
【００４７】
図９は、図１の無線局１−Ａ，１−Ｂ，１−Ｃ及び１−Ｄ間で実行される、送信元無線局側のＳＩＮＲテーブル及び空間相関テーブル生成処理におけるタイミングチャートである。無線局１−Ａは、ランダムなタイミングでＳＩＮＲテーブル及び空間相関テーブル生成のためのＳＥＴＵＰ信号をオムニパターンＯＰで送信する。ＳＥＴＵＰ信号を送信するときは、他の信号との衝突を回避するためにＣＳＭＡを用いる。図１０（ａ）は，このとき送信されるＳＥＴＵＰ信号のフレーム構成とフレーム長を示し、ＦＣ（Ｆｒａｍｅ　Ｃｏｎｔｒｏｌ）は当該信号のフレームの種類を定義し、Ｄ（Ｄｕｒａｔｉｏｎ）はフレームの種類などに応じたフレーム長を定義し、ＲＡ（Ｒｅｃｅｉｖｅｒ　Ａｄｄｒｅｓｓ）とＴＡ（Ｔｒａｎｓｍｉｔｔｅｒ　Ａｄｄｒｅｓｓ）はそれぞれ、あて先無線局と発信元無線局を示すアドレスであり、ＦＣＳ（Ｆｒａｍｅ　Ｃｈｅｃｋ　Ｓｅｑｕｅｎｃｅ）は、３２−ＣＲＣによる誤り検出のために用いられる。
【００４８】
無線局１−Ａのサービスエリア内に存在し、ＳＥＴＵＰ信号をオムニパターンＯＰで受信した無線局１−Ｂ，１−Ｃ及び１−Ｄは、受信信号の待機状態に入り、無線局１−Ａから引き続き既知のタイミングで送信されるＲＱ（０）乃至（３３０）信号を待機する。無線局１−Ａは、ＳＥＴＵＰ信号に引き続いて、ＲＱ（０）乃至（３３０）信号をそれぞれセクタパターンＳＰ（１）乃至（１２）で送信する。ＲＱ（０）乃至（３３０）信号は、無線局１−Ａの隣接無線局に、ＳＩＮＲテーブル及び空間相関テーブルのためのデータを提供させるための要求信号である。詳しくは、無線局１−Ａは、３０度ずつ異なる１２方向を向いた１２個のセクタパターンを一定の時間間隔かつ予め決められた順番で切り換えて、セクタパターンを切り換える毎に各ＲＱ（０）乃至（３３０）信号を送信する。各ＲＱ（０）乃至（３３０）信号には、当該セクタパターンの主ビーム方位角を表す方位角データと、無線局１−Ｂ，１−Ｃ及び１−Ｄが受信信号品質（すなわちＳＩＮＲ）を測定するためのトレーニング信号であるＳＥＳＴデータが含まれる。ＳＥＳＴデータは、シンボル数Ｐｔｓの既知のＰＮ（擬似雑音）信号である。図１０（ｂ）はＲＱ（０）信号乃至ＲＱ（３３０）信号のフレーム構成とフレーム長を示し、ＳＥＳＴは受信信号品質（すなわちＳＩＮＲ）を測定するために用いられる信号系列であり、ＳＣ（Ｓｅｑｕｅｎｃｅ　Ｃｏｎｔｒｏｌ）はパケットのシーケンス番号とフラグメント番号を示し、方位角データは、ＲＱ（０）乃至ＲＱ（３３０）信号を送信したときに発信元無線局１に設定されたセクタパターンＳＰ（１）乃至ＳＰ（１２）の方位角度を示す。フレーム中のＦＣ、Ｄ、ＲＡ、ＴＡ及びＦＣＳ信号は、ＳＥＴＵＰ信号と同様である。
【００４９】
ＳＥＴＵＰ信号を受信した無線局１−Ｂ，１−Ｃ及び１−Ｄは、無線局１−Ａから既知のタイミングで送信される１２個のＲＱ（０）乃至（３３０）信号をオムニパターンＯＰで受信し、各ＲＱ（０）乃至（３３０）信号のＳＥＳＴデータの部分に基づいて、方位角毎の受信信号品質を測定する。方位角毎の受信信号品質は、すなわち、ＲＱ（０）乃至（３３０）信号の送信時に無線局１−Ａでそれぞれ設定されたセクタパターンＳＰ（１）乃至（１２）の主ビーム方位角０度、３０度、…、３３０度のそれぞれに対する受信信号品質である。受信信号品質は本実施形態ではＳＩＮＲであるが、信号強度等の他の基準であってもよい。また、ＲＱ（０）乃至（３３０）信号はオムニパターンＯＰで受信されるのが基本であるが、信号中のＳＥＳＴデータの区間において適応制御パターンを形成し、その結果として得られる受信信号品質を取得することもできる。適応制御パターンは、外来雑音や同一チャンネル干渉あるいは隣接チャンネル干渉などの周囲の環境に応じて変化して、所望波信号に主ビームを向け、かつ干渉波信号にヌルを向けるためのアンテナパターンである。無線局１−Ｂ，１−Ｃ及び１−Ｄは、無線局１−Ａが１２個のセクタパターンＳＰ（１）乃至ＳＰ（１２）を切り換える毎に送信したＲＱ（０）乃至（３３０）信号に基づいている方位角毎のＳＩＮＲを、送信時のセクタパターンＳＰ（１）乃至ＳＰ（１２）の主ビーム方位角を示す方位角データとともにメモリ１５３に一旦記憶する。
【００５０】
無線局１−Ｂ，１−Ｃ及び１−Ｄでそれぞれ取得された上記方位角毎のＳＩＮＲの情報は、ＲＱ（０）乃至ＲＱ（３３０）信号に対する応答信号であるＲＥ信号によって、各無線局１−Ｂ，１−Ｃ及び１−Ｄから無線局１−Ａに送信される。図１０（ｃ）はＲＥ信号のフレーム構成とフレーム長を示す。ＲＥ信号の中で、ＥＳＣは、各無線局１−Ｂ，１−Ｃ及び１−Ｄの空間相関値を演算するために用いられる複数のトレーニング信号を示し、シンボル数Ｐｔｓの既知のＰＮ信号が７回繰り返されたｅｓｃ（１）乃至ｅｓｃ（７）信号で構成される。ＲＥ信号の中で、ＳＩＮＲテーブルデータは、発信側無線局１−ＡのセクタパターンＳＰ（１）乃至ＳＰ（１２）の主ビーム方位角に対応したＳＩＮＲの情報を示す。フレーム中のＦＣ、Ｄ、ＲＡ、ＴＡ、ＳＣ及びＦＣＳ信号は、ＳＥＴＵＰ信号及びＲＱ（０）乃至（３３０）信号と同様である。
【００５１】
ＲＥ信号を送信するときの各無線局１−Ｂ，１−Ｃ及び１−Ｄのアンテナパターンは、ＲＱ（０）乃至（３３０）信号を受信してＳＩＮＲを取得したときのアンテナパターン（オムニパターン又は適応制御パターン）に設定される。無線局１−Ｂ，１−Ｃ及び１−Ｄが送信するＲＥ信号には、図１０（ｃ）のフレーム構成に示されたように、フレームの先頭に空間相関値の演算に用いるためのＥＳＣ信号が付加されている。各無線局１−Ｂ，１−Ｃ及び１−ＤがＲＥ信号を無線局１−Ａに送信するときは、ＳＥＴＵＰ信号を送信するときと同様にＣＳＭＡによって各ＲＥ信号の衝突が回避される。最終的に、数１によって空間相関値を取得するためには受信波が１波のみである必要があるが、この場合、各無線局１−Ｂ，１−Ｃ及び１−ＤからのＲＥ信号がＣＳＭＡによって衝突を回避される。
【００５２】
図９に例示されたタイミングチャートにおいて、無線局１−Ａは、まず、無線局１−Ｃから送信されるＲＥ信号を受信する。ＲＥ信号に含まれるＥＳＣ信号を受信するときには、７回巡回される既知の符号のｅｓｃ（１）乃至ｅｓｃ（７）信号に合わせて、リアクタンス値テーブルに従ってオムニパターンＯＰと、セクタパターンＳＰ（１），ＳＰ（３），ＳＰ（５），ＳＰ（７），ＳＰ（９）及びＳＰ（１１）を順次に切り換える。それぞれのアンテナパターンで受信されたｅｓｃ（１）乃至ｅｓｃ（７）信号は、受信信号系列ｙ_０（ｔ），ｙ_１（ｔ），…，ｙ_６（ｔ）として、一旦、メモリ１５３に記憶される。
【００５３】
無線局１−ＣからのＲＥ信号に含まれたＳＩＮＲテーブルデータの情報は、ＳＩＮＲテーブルに書き込まれる。ＳＩＮＲテーブルは、データベースメモリ１５４中で所定の記憶領域を割り当てられ、ＳＩＮＲテーブルデータが取得された無線局１の順に書き込まれる。ＳＩＮＲテーブルデータが取得されなかったとき、ＳＩＮＲテーブルの記憶領域は空白にされる。
【００５４】
次に、無線局１−Ａは無線局１−Ｄから送信されるＲＥ信号も同様に処理する。この時点で、無線局１−ＡのＳＩＮＲテーブルには、無線局１−Ｃ及び１−ＤのＳＩＮＲテーブルデータが書き込まれており、また、メモリ１５３には、空間相関値の演算のために、無線局１−Ｃ及び１−Ｄの受信信号系列の情報が記憶されている。
【００５５】
メモリ１５３に記憶された各無線局１−Ｃ及び１−Ｄの受信信号系列の情報により、数２及び数１を用いて、無線局１−Ａが無線局１−Ｃを所望波無線局とし、無線局１−Ｄを干渉波無線局とした場合と、無線局１−Ａが無線局１−Ｄを所望波無線局とし、無線局１−Ｃを干渉波無線局とした場合との空間相関テーブルが生成される。ただし、数１から明らかなように、２つの近傍無線局のどちらを所望波無線局として他方を干渉波無線局とみなしても、空間相関値は同一である。空間相関テーブルは、データベースメモリ１５４中で所定の記憶領域を割り当てられ、空間相関値が取得された無線局１の対の順に書き込まれる。空間相関値が取得されなかったとき、空間相関テーブルの記憶領域は空白にされる。
【００５６】
次に、無線局１−Ａは無線局１−Ｂから送信されるＲＥ信号を受信し、同様にＳＩＮＲテーブルを生成し、さらに、無線局１−Ａが無線局１−Ｂを所望波無線局とし、無線局１−Ｃを干渉波無線局とした場合や、無線局１−Ａが無線局１−Ｃを所望波無線局とし、無線局１−Ｂを干渉波無線局とした場合など、これまでにＲＥ信号を受信したすべての無線局１の組み合わせにおいて空間相関値を演算し、空間相関テーブルを生成する。
【００５７】
このように作られたＳＩＮＲテーブルと空間相関テーブルを基に、周囲の無線局１の相対位置と無線局１間の電波環境の状況が把握できるため、最適なルート選択ができるようになる。また、通信中の無線局１が位置する方向への送信を制限し、複数組のユーザ端末間の通信を同時に成立させるＳＤＭＡもできるようになる。以上説明したように、従来例に係るＳＩＮＲテーブルを生成するための信号と同様の信号を用いて、ＳＩＮＲテーブルを生成するだけでなく、同時に空間相関テーブルも生成することができる。各テーブルを生成するために必要な通信量を増大させることなく無線ネットワークを制御して、当該無線ネットワークのスループットを増大させることができる。
【００５８】
以上の構成された通信装置において、所望波を送信する第１の無線局と無線通信を行うときに、計算された空間相関係数が所定のしきい値以上であるとき、干渉はを送信する第２の無線局に対して送信規制要求信号を送信することにより送信規制を行い、第１の無線局との無線通信を終了した後、第２の無線局に対して送信規制解除信号を送信することにより送信規制解除を行う。
【００５９】
以上説明したように、本実施形態によれば、特別な信号を他に送受信する必要なく、ＳＩＮＲテーブルの生成と同時に空間相関テーブルを生成することができ、空間相関テーブルに基づいて干渉波を送信する無線局に対して送信規制を行うことができる。これにより、アドホック無線ネットワークなどの無線ネットワークにおいて、適切に発信規制を行うことができ、無線ネットワーク全体のスループットの低下を防止することができる。
【００６０】
＜第２の実施形態＞
以下、本発明に係る第２の実施形態の無線ネットワークのための通信装置について説明する。第１の実施形態では、ＳＥＴＵＰ信号を送信する側の無線局１においてＳＩＮＲテーブルと空間相関テーブルが生成されたが、第２の実施形態では、ＳＥＴＵＰ信号を受信する側の無線局１においてＳＩＮＲテーブルと空間相関テーブルが生成されるので、各テーブルを生成するために必要な通信量を減少させることができる。
【００６１】
図１１は、本発明に係る第２の実施形態の受信無線局側のＳＩＮＲテーブル及び空間相関テーブル生成処理においてエスパアンテナ装置１０１に設定される指向性パターンの実施例を示す指向特性図である。この図に示された例では、５つの無線局１−Ａ乃至１−Ｅが存在している。３つの無線局１−Ａ，１−Ｂ及び１−Ｄは、それぞれ他の２つの無線局１がオムニパターンＯＰで送信した場合、その信号を受信できる位置に存在する。無線局１−Ｃは、無線局１−Ａ，１−Ｂ，１−Ｄ及び１−Ｅがオムニパターンで、無線局１−Ｃ自体もオムニパターンのときは、無線局１−Ａと無線局１−Ｅの信号を受信できる位置に存在する。
【００６２】
各無線局１は、ＳＩＮＲテーブルと空間相関テーブルを生成するためのＳＥＴＵＰ／ＲＱＳＣ信号（図１３を参照）を送信するときは、図５のリアクタンス値テーブルに従ってオムニパターンＯＰをエスパアンテナ装置１０１に設定する。一方、各無線局１は、上記送信されたＳＥＴＵＰ信号を受信するときはオムニパターンＯＰをエスパアンテナ装置１０１に設定するが、ＳＥＴＵＰ信号に続くＲＱＳＣ信号中のｅｓｃ（１）信号を受信するときは、主ビーム方位角が０度方向を向いたセクタパターンＳＰ（１）をエスパアンテナ装置１０１に設定し、ｅｓｃ（１）信号に続くｅｓｃ（２）信号を送信するときは、主ビーム方位角が３０度方向を向いたセクタパターンＳＰ（２）をエスパアンテナ装置１０１に設定し、以下同様に主ビーム方位角が３３０度方向を向いたセクタパターンＳＰ（３３０）まで設定する。各無線局１がｅｓｃ（１２）信号に続くｅｓｃ（１３）信号を受信するときは、再びオムニパターンＯＰをエスパアンテナ装置１０１に設定する。
【００６３】
図１２は、本発明に係る第２の実施形態において無線局１−Ａ，１−Ｂ，１−Ｃ及び１−Ｄ間で実行される、受信無線局側のＳＩＮＲテーブル及び空間相関テーブル生成処理におけるタイミングチャートである。無線局１−Ａは、ランダムなタイミングでＳＥＴＵＰ／ＲＱＳＣ信号をオムニパターンＯＰで送信する。ＳＥＴＵＰ／ＲＱＳＣ信号の送信には、他の信号との衝突を回避するためにＣＳＭＡを用いる。図１３は、このとき送信されるＳＥＴＵＰ／ＲＱＳＣ信号のフレーム構成とフレーム長を示す図である。ＳＥＴＵＰ信号に含まれる各データＦＣ，Ｄ，ＲＡ，ＴＡ及びＦＣＳの意味は、第１の実施形態と同様である（図１０を参照）。ＲＱＳＣ信号は、各無線局１の空間相関値を演算するために用いられる複数のトレーニング信号であり、それぞれ所定のシンボル数Ｐｔｓを有する既知のＰＮ信号を含むｅｓｃ（１）乃至ｅｓｃ（１３）信号より構成される。
【００６４】
無線局１−Ａのサービスエリア内に存在し、ＳＥＴＵＰ信号をオムニパターンＯＰで受信した無線局１−Ｂ，１−Ｃ及び１−Ｄは、受信信号の待機状態に入り、無線局１−Ａから既知のタイミングで送信されてくるＲＱＳＣ信号の待ち受け状態になる。
【００６５】
無線局１−Ａは、ＳＥＴＵＰ信号に引き続いて、あらかじめ決められた長さ及び間隔で、ＲＱＳＣ信号をオムニパターンＯＰで送信する。ＲＱＳＣ信号は、上述のようにシンボル数Ｐｔｓのｅｓｃ信号の１３回の繰り返しで構成される。ＳＥＴＵＰ信号を受信して待機状態になっている無線局１−Ｂ，１−Ｃ及び１−Ｄは、無線局１−Ａから既知のタイミングで送信されてくるｅｓｃ（１）乃至ｅｓｃ（１２）信号に合わせて、１２個のセクタパターンＳＰ（１）乃至ＳＰ（１２）を切り換えて上記ｅｓｃ（１）乃至ｅｓｃ（１２）信号を順次に受信し、セクタパターンＳＰ（１）乃至ＳＰ（１２）のそれぞれの角度に対する受信信号品質（例えばＳＩＮＲ）を測定し、無線局１−Ａに対するＳＩＮＲテーブルを生成する。ｅｓｃ（１３）信号はオムニパターンＯＰで受信されるが、ＳＩＮＲテーブルの生成には用いられない。
【００６６】
本実施形態のように、受信無線局１側で生成されるＳＩＮＲテーブルでは、第１の実施形態でのＳＩＮＲテーブル（図７を参照）とは異なり、ある無線局１の隣接無線局から送信され、当該無線局１で受信された無線信号のＳＩＮＲ値が記録される。従って、本実施形態において、無線局１−ＡのＳＩＮＲテーブルであって、無線局１−Ａに隣接した無線局１−Ｃ，１−Ｄ及び１−ＢについてのＳＩＮＲ値のテーブルには、無線局１−Ｃ，１−Ｄ及び１−Ｂから送信され、無線局１−Ａによって受信された無線信号のＳＩＮＲ値が、その受信時の方位角毎に記録される。
【００６７】
以上のように受信されたｅｓｃ（１）乃至ｅｓｃ（１３）信号を用いて、空間相関テーブルも生成される。無線局１−Ｂ，１−Ｃ及び１−Ｄは、受信したＳＥＴＵＰ／ＲＱＳＣ信号のうち、セクタパターンＳＰ（１），ＳＰ（３），ＳＰ（５），ＳＰ（７），ＳＰ（９）及びＳＰ（１１）で受信した各ｅｓｃ（１），ｅｓｃ（３），ｅｓｃ（５），ｅｓｃ（７），ｅｓｃ（９）及びｅｓｃ（１１）信号にてなる受信信号ｙ_１（ｔ），…，ｙ_６（ｔ）をそれぞれメモリ１５３に記憶しておく。１３番目のｅｓｃ信号はオムニパターンＯＰで受信して、受信信号ｙ_０（ｔ）としてメモリ１５３に記憶する。
【００６８】
無線局１−ＡがＳＥＴＵＰ／ＲＱＳＣ信号を送信した後、次に、無線局１−ＢがＳＥＴＵＰ／ＲＱＳＣ信号を送信し、無線局１−Ａ，１−Ｃ及び１−Ｄは上と同様に、ｅｓｃ（１）乃至ｅｓｃ（１２）信号に基づいて無線局１−Ｂに対するＳＩＮＲテーブルを生成するとともに、ｅｓｃ（１），ｅｓｃ（３），ｅｓｃ（５），ｅｓｃ（７），ｅｓｃ（９），ｅｓｃ（１１）及びｅｓｃ（１３）信号から、無線局１−Ｂの受信信号系列ｙ_０（ｔ），…，ｙ_６（ｔ）を取得して、それぞれの無線局１のメモリ１５３に記憶する。
【００６９】
この時点で、無線局１−Ｃ及び１−Ｄは、無線局１−Ａ及び１−Ｂの各受信信号系列をメモリ１５３に記憶しているので、上記受信信号系列に基づいて数２及び数１を用いて無線局１−Ａと１−Ｂの間の空間相関値を計算することができる。無線局１−Ｃ及び１−Ｄは、空間相関値を計算し、その結果を空間相関テーブルとして生成してデータベースメモリ１５４に記憶する。同様に、無線局１−Ｃ及び１−Ｄは、ＣＳＭＡで衝突を防止しながらＳＥＴＵＰ／ＲＱＳＣ信号を送信し、上記信号を受信した他の無線局１は、ＳＩＮＲテーブルと空間相関テーブルを生成して、データベースメモリ１５４に記憶する。
【００７０】
同様に、無線局１−Ａ，１−Ｂ，１−Ｃ及び１−Ｄは、順次に各無線局が有する一定のタイミングで、ＣＳＭＡによって衝突を回避しながら、ＳＥＴＵＰ／ＲＱＳＣ信号を送信し、ＳＥＴＵＰ／ＲＱＳＣ信号を受信した無線局１はＳＩＮＲテーブルを生成し、また、２つの異なる無線局１から送信されたＳＥＴＵＰ／ＲＱＳＣ信号を受信した無線局１は、数２及び数１を用いて空間相関テーブルを生成する。
【００７１】
以上説明したように、すべての無線局１がＳＥＴＵＰ／ＲＱＳＣ信号をある一定周期で周期的に送信することにより、ＳＩＮＲテーブルと空間相関テーブルとが各無線局１に生成される。例えば電源を入れた後、ある一定の期間はこのテーブルを生成するための期間とし、その後通信できるような方法を用いてもよい。
【００７２】
第１の実施形態で説明されたＳＩＮＲテーブル及び空間相関テーブル生成処理は、送信側無線局１からのＲＱ（０）乃至ＲＱ（３３０）信号に応答するＲＥ信号を用いて、送信側無線局１が順次ＳＩＮＲテーブル及び空間相関テーブルを生成していく方法である。そのため、ＳＥＴＵＰ信号を受信したすべての無線局１の情報が送信無線局１に集まるという利点があるが、ＳＥＴＵＰ信号及びＲＱ（０）乃至ＲＱ（３３０）信号と、ＲＥ信号とが各無線局１間で往復する動作が存在する。第２の実施形態では、ＳＥＴＵＰ／ＲＱＳＣ信号が１つの無線局１から他の無線局１に送信されることのみを含むので、第１の実施形態に比べて、必要な通信量を減少させることができる。
【００７３】
図１４は、第１又は第２の実施形態に従って生成され、データベースメモリ１５４に記憶された空間相関テーブルを用いた発信規制処理の実施例を示すタイミングチャートである。この実施例では、図１１のように５つの無線局１−Ａ乃至１−Ｅが存在したアドホック無線ネットワークにおいて、図７の空間相関テーブルを参照して発信規制処理を実行している。無線局１−Ａ，１−Ｂ及び１−Ｄは、それぞれ他の２つの無線局１がオムニパターンＯＰで送信した場合、その信号を受信できる位置に存在する。無線局１−Ｃは、無線局１−Ａ，１−Ｂ，１−Ｄ及び１−Ｅがオムニパターンで、無線局１−Ｃ自体もオムニパターンのときは、無線局１−Ａと無線局１−Ｅの信号を受信できる位置に存在する。なお、このアドホック無線ネットワークは無線ＬＡＮのＩＥＥＥ８０２．１１ｂ規格をベースとして構成することができる。
【００７４】
無線局１−Ｃが無線局１−Ａに対して通信を開始する。まず、無線局１−Ｃは無線局１−Ａに対してＲＴＳ（Ｒｅｑｕｅｓｔ　ｔｏ　ｓｅｎｄ）信号をオムニパターンＯＰで送信する。ＲＴＳ信号の送信前に、無線局１−Ｃはそれの空間相関テーブルを参照し、無線局１−Ａとの空間相関値が所定のしきい値（例えば、０．９）以上である無線局１の有無を確認する。空間相関値がしきい値を超過する無線局１（被規制局と呼ぶ。）に対しては、ＲＴＳ信号に発信規制開始要求信号を付加して送信する。図７（ｃ）の場合には、被規制局は存在しない。
【００７５】
無線局１−Ａは無線局１−ＣからのＲＴＳ信号を受信し、無線局１−Ａに対するＣＴＳ（Ｃｌｅａｒ　ｔｏ　ｓｅｎｄ）信号を無線局１−Ｃに送信する。ＣＴＳ信号の送信前に、無線局１−Ａはそれの空間相関テーブルを参照し、無線局１−Ｃとの空間相関値がしきい値以上である端末の有無を確認する。空間相関値がしきい値を超過する無線局１に対しては、ＣＴＳ信号に発信規制開始要求信号を付加して送信する。図７（ａ）の場合は、被規制局は無線局１−Ｂである。
【００７６】
無線局１−Ｃは、ＣＴＳ信号を受信すると、無線局１−Ａに対するデータの送信を開始する。無線局１−Ａは無線局１−ＣからのデータであるＤＡＴＡ１，ＤＡＴＡ２，…，ＤＡＴＡｎ信号を受信する毎に、肯定応答のＡＣＫ１，ＡＣＫ２，…，ＡＣＫｎ信号を無線局１−Ａに送信する。発信元無線局１−Ｃは、いずれかの干渉波無線局１に発信規制開始要求信号を送信したときには、最後のデータＤＡＴＡｎ信号を送信して、それに対する肯定応答ＡＣＫｎ信号を受信した後で、同じ干渉波無線局１に規制解除要求信号を送信して発信規制を解除する。また、あて先無線局１−Ａは、干渉波無線局１に発信規制開始要求信号を送信したときには、最後の肯定応答ＡＣＫｎ信号を送信した後で、同じ干渉波無線局１に規制解除要求信号を送信して発信規制を解除する。
【００７７】
無線局１−Ｃが送信したＲＴＳ信号と無線局１−Ａが送信したＣＴＳ信号とを受信した無線局１−Ｂ，１−Ｄ及び１−Ｅは、自局が無線局１−Ａ及び１−Ｃの通信相手ではないということを、ＲＴＳ信号とＣＴＳ信号に含まれる発信元無線局とあて先無線局のアドレスによって確認するとともに、自局あての発信規制開始要求信号がＲＴＳ信号とＣＴＳ信号に含まれているか否かを確認する。自局あての発信規制開始要求信号がＲＴＳ信号とＣＴＳ信号に含まれている場合には、発信規制開始要求信号を受信した後に所定のタイムアウト時間が経過するか、又は発信規制開始要求信号を送信した同じ無線局１によって送信された規制解除要求信号を受信するまで、当該無線局は、無線局１−Ｃ及び１−Ａに対して干渉波となる電波を放射しないように、発信を規制する。自局あての発信規制開始要求信号がＲＴＳ信号とＣＴＳ信号に含まれていない場合には、ＲＴＳ信号やＣＴＳ信号を受信していても送信できる。
【００７８】
このような手順にて、空間相関値を利用して、真に発信規制されることが必要な無線局１のみに発信規制開始要求信号を送信することによって、従来のようにＲＴＳ信号とＣＴＳ信号を受信したすべての無線局１が送信できなくなる状態を回避し、隠れ端末存在の可能性を減らしつつ、ＳＤＭＡが可能であるにも関わらず発信規制される無線局１の数も減少させることができるので、ネットワーク全体のスループットの向上を期待できる。
【００７９】
本発明に係る実施形態では、１２パターンのセクタパターンＳＰ（１）乃至ＳＰ（１２）を用いてＳＩＮＲテーブルを生成し、６パターンのセクタパターンＳＰ（１），（３），（５），（７），（９）及び（１１）とオムニパターンＯＰとを用いて空間相関テーブルを生成したが、これとは異なる個数及び／又は形状のアンテナパターンを用いて各テーブルを生成可能であることは明らかであろう。
【００８０】
以上の実施形態においては、アドホック無線ネットワークによる通信の前段階において、エスパアンテナのリアクタンスを制御することによって測定された空間相関値を利用したＭＡＣ（Ｍｅｄｉａ　Ａｃｃｅｓｓ　Ｃｏｎｔｒｏｌ）の通信方法を提案した。従来例において提案されたＳＩＮＲテーブル方式のシーケンスを変えることなく空間相関値を測定する第１の実施形態に係る方式と、受信無線局側で空間相関テーブルを生成する新規な第２の実施形態に係る方式とを示し、適応制御で防ぎきれない干渉波が発生することを防ぎ、ＳＤＭＡが可能であるにも関わらず発信規制される無線局を減らすことができる。
【００８１】
【発明の効果】
以上詳述したように、本発明に係る無線ネットワークの制御方法によれば、複数の無線局を含み、各無線局間で無線通信を行う無線ネットワークのための通信方法及び通信装置において、指向特性を変化可能なアレーアンテナの互いに異なる指向特性を有する複数の放射パターンを用いて第１の無線局からの所望波の無線信号をそれぞれ受信し、当該受信した各受信信号と、送信される信号と同一の基準信号とを要素とする所望波の受信応答ベクトルｒ_ｄを求め、上記アレーアンテナの複数の放射パターンを用いて第２の無線局からの干渉波の無線信号をそれぞれ受信し、当該受信した各受信信号と、送信される信号と同一の基準信号とを要素とする干渉波の受信応答ベクトルｒ_ｉを求め、上記所望波の受信応答ベクトルｒ_ｄと、上記干渉波の受信応答ベクトルｒ_ｉとに基づいて、所望波と干渉波との間の空間相関係数を計算し、上記第１の無線局と無線通信を行うときに、上記計算された空間相関係数が所定のしきい値以上であるとき、上記第２の無線局に対して送信規制要求信号を送信する。従って、アドホック無線ネットワークなどの無線ネットワークにおいて、適切に発信規制を行うことができ、無線ネットワーク全体のスループットの低下を防止することができる。
【図面の簡単な説明】
【図１】本発明に係る第１の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−Ａ乃至１−Ｉの平面配置図である。
【図２】図１の各無線局１の内部構成を示すブロック図である。
【図３】図２のエスパアンテナ装置１０１の構成を示す斜視図である。
【図４】図３のエスパアンテナ装置１０１の縦断面図である。
【図５】図２のデータベースメモリ１５４に予め記憶されるリアクタンス値テーブルの実施例を示す表である。
【図６】図２のデータベースメモリ１５４に記憶されたＳＩＮＲテーブルを示す表である。
【図７】図２のデータベースメモリ１５４に記憶された空間相関テーブルを示す表であり、（ａ）は無線局１−Ａの空間相関テーブルを示し、（ｂ）は無線局１−Ｂの空間相関テーブルを示し、（ｃ）は無線局１−Ｃの空間相関テーブルを示し、（ｄ）は無線局１−Ｄの空間相関テーブルを示す表である。
【図８】図１の無線局１−Ａにおけるエスパアンテナ装置１０１の指向性パターンの実施例を示す指向特性図である。
【図９】図１の無線局１−Ａ，１−Ｂ，１−Ｃ，１−Ｄ間で実行される、送信元無線局側のＳＩＮＲテーブル及び空間相関テーブル生成処理におけるタイミングチャートである。
【図１０】図１の各無線局１間で送受信される、送信元無線局側のＳＩＮＲテーブル及び空間相関テーブル生成処理のための各信号のフレーム構成とフレーム長を示す信号フォーマット図であり、（ａ）はＳＥＴＵＰ信号を示し、（ｂ）はＲＱ（０）信号乃至ＲＱ（３３０）信号を示し、（ｃ）はＲＥ信号を示す図である。
【図１１】本発明に係る第２の実施形態の受信無線局側のＳＩＮＲテーブル及び空間相関テーブル生成処理においてエスパアンテナ装置１０１に設定される指向性パターンの実施例を示す指向特性図である。
【図１２】図１１の無線局１−Ａ，１−Ｂ，１−Ｃ，１−Ｄ間で実行される、受信無線局側のＳＩＮＲテーブル及び空間相関テーブル生成処理におけるタイミングチャートである。
【図１３】図１１の各無線局１間で実行される、受信無線局側のＳＩＮＲテーブル及び空間相関テーブル生成処理のための各信号のフレーム構成とフレーム長を示す信号フォーマット図である。
【図１４】図７の空間相関テーブルを用いて実行される発信規制処理の実施例を示すタイミングチャートである。
【符号の説明】
１，１−Ａ乃至１−Ｉ…無線局、
１０１…エスパアンテナ装置、
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…学習シーケンス信号発生器、
１５３…メモリ、
１５４…データベースメモリ、
１６０…拡散符号発生器。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a communication method and a communication device for a wireless network, and more particularly, to a wireless network such as an ad hoc wireless network having a plurality of wireless stations and performing wireless communication in a wireless network such as a wireless LAN. The present invention relates to a communication method and a communication device.
[0002]
[Prior art]
In an ad hoc wireless network that wirelessly supports communication between an unspecified number of people who are temporarily gathered in a specific area, users in the network cannot operate without the infrastructure such as an Internet router device. It is necessary to relay packets in a coordinated manner and perform routing.
[0003]
As a routing method of an ad hoc wireless network, for example, in a conventional example described in Patent Literature 1, a wireless station of each user terminal in the network has a service area for each predetermined azimuth in a horizontal plane centered on the own station. The signal-to-interference-plus-noise ratio (SINR) for each user terminal is measured in advance, and the main beam is directed to the destination station and null is directed to the other radio stations with reference to the SINR table stored in a table format. Thus, controlling a variable beam antenna is disclosed. In particular, in the routing method of Patent Document 1, a routing method for a wireless network that includes a plurality of wireless stations and performs packet communication between the wireless stations. And beforehand storing interference noise for each predetermined azimuth angle in a storage device as an SINR table, and transmitting a first hop radio station based on the SINR table when transmitting a packet to a destination radio station. Routing the packet by controlling the variable beam antenna and transmitting the packet so as to form a beam for the determined first hop radio station. . In this conventional example, since the relative position of the surrounding wireless stations and the state of the radio wave environment between the wireless stations can be grasped based on the SINR table, the optimum route can be selected. Also, it is possible to realize SDMA (Space Division Multiple Access) that restricts transmission in the direction of a communicating wireless station and establishes communication between a plurality of sets of user terminals simultaneously.
[0004]
As the variable beam antenna, for example, an electronically controlled steerable passive array antenna (ESPAR) Antenna proposed in Patent Literature 2 and Non-Patent Literatures 1 and 2 is referred to as an ESPAR antenna. Can be used. The ESPAR antenna is provided with an excitation element to which a radio signal is supplied, a plurality of non-excitation elements which are provided at a predetermined distance from the excitation element and are not supplied with a radio signal, and a variable reactance connected to each of the non-excitation elements. An array antenna including an element (for example, a variable capacitance diode) is provided, and by changing the reactance value of the variable reactance element, the directional characteristics of the array antenna can be changed.
[0005]
[Patent Document 1]
JP 2001-244983 A.
[Patent Document 2]
JP 2001-24431 A.
[Non-patent document 1]
T. Ohira et al. , "Electronically steerable passive array radiator antennas for low-cost analog adaptive beamforming," 2000 IEEE International negotiations. 101-104, Dana point, California, May 21-25, 2000.
[Non-patent document 2]
Takashi Ohira, "Basic formulation on equivalent weight vector and gradient of ESPAR antenna", IEICE Technical Report, A. P 2001-16, p. 15-20, May 2001.
[0006]
[Problems to be solved by the invention]
However, when performing routing with reference to the SINR table indicating the state of the surrounding wireless environment, in the conventional control using the RTS signal and the CTS signal, transmission is restricted even in a wireless station that can originally perform SDMA. A situation arises. For example, in a communication in a multipath environment, even if a certain wireless station exists in the same sector direction as the destination wireless station as viewed from the source wireless station, the wireless station is located between the source wireless station and the destination wireless station. May not interfere with communication. Therefore, referring to the SINR table, it is not possible to regard the radio station as a potential interference signal source and request the transmission restriction only because the radio station is located in the same sector direction as the desired radio station. However, there is a problem that the implementation of SDMA which may be actually possible is hindered, and the throughput of the network may be reduced.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, and in a wireless network such as an ad-hoc wireless network, it is possible to appropriately perform outgoing call regulation and to prevent a decrease in throughput of the entire wireless network. A communication method and a communication device are provided.
[0008]
[Means for Solving the Problems]
A communication method for a wireless network according to the present invention includes a plurality of wireless stations, in a communication method for a wireless network performing wireless communication between each wireless station,
Radio signals of a desired wave from the first radio station are respectively received by using a plurality of radiation patterns having different directivity characteristics of an array antenna capable of changing the directivity characteristics, and the received signals are transmitted and transmitted. Reception response vector r of the desired wave having the signal and the same reference signal as elements _d , And receives a radio signal of an interference wave from the second radio station using a plurality of radiation patterns of the array antenna, and converts each of the received signals and a reference signal identical to a signal to be transmitted. Reception response vector r of the interference wave as an element _i , And the reception response vector r of the desired wave _d And the reception response vector r of the interference wave _i Calculating a spatial correlation coefficient between the desired wave and the interference wave based on
Transmitting a transmission restriction request signal to the second wireless station when the calculated spatial correlation coefficient is equal to or greater than a predetermined threshold when performing wireless communication with the first wireless station; And characterized in that:
[0009]
In the communication method for the wireless network, a transmission restriction request signal is transmitted to the second wireless station, and after terminating wireless communication with the first wireless station, the transmission control request signal is transmitted to the second wireless station. And transmitting a transmission restriction release signal.
[0010]
In the communication method for the wireless network, the step of calculating the spatial correlation coefficient is transmitted using a plurality of radiation patterns of the array antenna in response to a request signal from each of the wireless stations. Receiving the radio signals from the respective radio stations to calculate the spatial correlation coefficient between the respective radio stations.
[0011]
Further, in the communication method for the wireless network, the step of calculating the spatial correlation coefficient includes, using a plurality of radiation patterns of the array antenna, the wireless signal from each of the wireless stations transmitted periodically. The method is characterized in that a spatial correlation coefficient between each wireless station is calculated by receiving each of them.
[0012]
Still further, in the communication method for a wireless network, the plurality of radiation patterns include an omni pattern having an omnidirectional characteristic and a plurality of sector patterns having a predetermined beam width and different beam directions from each other. It is characterized by.
[0013]
Still further, in the communication method for the wireless network, the array antenna includes an excitation element for transmitting and receiving a radio signal, a plurality of non-excitation elements provided at a predetermined interval from the excitation element, A plurality of variable reactance elements respectively connected to the plurality of parasitic elements, and by changing the reactance value of each of the variable reactance elements, the plurality of parasitic elements are operated as a director or a reflector, respectively. And changing the directivity of the array antenna.
[0014]
A communication device for a wireless network according to the present invention includes a plurality of wireless stations, in a communication device for a wireless network performing wireless communication between each wireless station,
Radio signals of a desired wave from the first radio station are respectively received by using a plurality of radiation patterns having different directivity characteristics of an array antenna capable of changing the directivity characteristics, and the received signals are transmitted and transmitted. Reception response vector r of the desired wave having the signal and the same reference signal as elements _d , And receives a radio signal of an interference wave from the second radio station using a plurality of radiation patterns of the array antenna, and converts each of the received signals and a reference signal identical to a signal to be transmitted. Reception response vector r of the interference wave as an element _i , And the reception response vector r of the desired wave _d And the reception response vector r of the interference wave _i Based on, calculating means for calculating the spatial correlation coefficient between the desired wave and the interference wave,
Control for transmitting a transmission restriction request signal to the second wireless station when the calculated spatial correlation coefficient is equal to or greater than a predetermined threshold when performing wireless communication with the first wireless station; Means.
[0015]
In the communication device for the wireless network, the control unit transmits a transmission restriction request signal to the second wireless station, and after terminating wireless communication with the first wireless station, sets the second The transmission restriction release signal is transmitted to the wireless station.
[0016]
Further, in the communication device for the wireless network, the calculating means is transmitted using a plurality of radiation patterns of the array antenna in response to a request signal from each of the wireless stations. , And calculates a spatial correlation coefficient between the wireless stations by receiving the wireless signals.
[0017]
Further, in the communication device for the wireless network, the calculating means, by using a plurality of radiation patterns of the array antenna, by receiving a wireless signal from each of the wireless stations transmitted periodically, It is characterized in that a spatial correlation coefficient between each wireless station is calculated.
[0018]
Still further, in the communication device for the wireless network, the plurality of radiation patterns include an omni pattern having an omnidirectional characteristic and a plurality of sector patterns having a predetermined beam width and different beam directions from each other. It is characterized by.
[0019]
Still further, in the communication device for the wireless network, the array antenna includes an excitation element for transmitting and receiving a radio signal, a plurality of non-excitation elements provided at a predetermined distance from the excitation element, A plurality of variable reactance elements respectively connected to the plurality of parasitic elements, and by changing the reactance value of each of the variable reactance elements, the plurality of parasitic elements are operated as a director or a reflector, respectively. And changing the directivity of the array antenna.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
<First embodiment>
FIG. 1 shows a plurality of wireless stations 1-A to 1-I (collectively, 1) forming an ad hoc wireless network using a communication device for a wireless network according to a first embodiment of the present invention. 2 is a block diagram showing an internal configuration of each wireless station 1 in FIG.
[0022]
The communication device of this embodiment is applied to a packet communication system of an ad hoc wireless network such as a wireless LAN, for example, and includes an ESPAR antenna device 101 capable of changing the direction of a main beam. Using a plurality of radiation patterns having different directivity characteristics, a radio signal of a desired wave is received from the first radio station, and each of the received signals and the same reference signal as the transmitted signal are used as elements. Response vector r of the desired wave _d , And receives the radio signals of the interference wave from the second radio station using the plurality of radiation patterns of the array antenna, and converts each of the received signals and the same reference signal as the transmitted signal into an element. The reception response vector r of the interference wave _i Is calculated, and a spatial correlation coefficient between the desired wave and the interference wave is calculated. When performing wireless communication with the first wireless station, the calculated spatial correlation coefficient is equal to or larger than a predetermined threshold. At this time, transmission restriction is performed by transmitting a transmission restriction request signal to the second wireless station, and after completing wireless communication with the first wireless station, transmission restriction is performed on the second wireless station. The transmission restriction is released by transmitting a release signal.
[0023]
In the wireless communication system of this embodiment, as shown in FIG. 1, a plurality of wireless stations 1 are scattered in a plane, and each wireless station 1 has a gain, transmission power, reception sensitivity, Has a predetermined service area determined by parameters such as the above, and can perform packet communication within this service area. When performing packet communication with the wireless station 1 outside the service area, the wireless station 1 within the service area Is used as a relay station to relay the packet data, thereby transmitting the packet data to a desired destination wireless station 1. That is, each wireless station 1 includes a router device that performs packet routing, and operates as a transmitting terminal, a relay station, or a destination terminal.
[0024]
Next, the device configuration of each wireless station 1 will be described with reference to FIG. In FIG. 2, a wireless station 1 includes an ESPAR antenna device 101, a directivity control unit 103 for controlling the directivity thereof, a circulator 102, a data packet transmitting / receiving unit including a data packet transmitting unit 140 and a data packet receiving unit 130. 104, a traffic monitor unit 105, a line control unit 106, and an upper layer processing unit 107.
[0025]
Transmission signal data for communication in packet format generated by the upper layer processing device 107 that processes data to be transmitted / received is input to the modulator 143 via the transmission buffer memory 142, and the modulator 143 transmits a signal of a predetermined radio frequency. The carrier signal is spread-spectrum-modulated by the spread code generator 160 according to the input communication transmission signal data using a predetermined communication channel spreading code generated by, for example, CDMA, and the modulated transmission signal is converted. Output to the high frequency transmitter 144. After performing processing such as amplification on the input transmission signal, the high-frequency transmitter 144 transmits the signal from the ESPAR antenna device 101 to another wireless station 1 via the circulator 102. On the other hand, the reception signal for the communication channel in the packet format received by the ESPAR antenna device 101 is input to the high frequency receiver 131 via the circulator 102, and the high frequency receiver 131 applies low noise amplification to the input reception signal. After the processing of (1) is performed, the output is output to the demodulator 132. Demodulator 132 demodulates the input received signal by spectrum despreading using a spread code for a communication channel generated by CDMA method in spread code generator 160, and demodulates the received signal data after demodulation to an upper layer. Output to the processing device 107 and output to the traffic monitor unit 105 for traffic monitoring.
[0026]
In this embodiment, the antenna device of the wireless station 1 includes a plurality of antenna elements, and controls the directivity of the ESPAR antenna device 101, which is a spatially synthesized array antenna that forms a beam by electromagnetic field coupling between the antenna elements. The antenna includes a pointing control unit 103 and can change the direction of a main beam having a predetermined beam width at predetermined scanning intervals by electrical control, for example, as shown in FIG.
[0027]
FIG. 3 is a perspective view showing the configuration of the ESPAR antenna device 101 of FIG. In FIG. 3, the ESPAR antenna device 101 includes an excitation element A0 and non-excitation elements A1 to A6 provided on the ground conductor 11, and the excitation element A0 includes six excitation elements A provided on a circumference having a radius R. It is arranged so as to be surrounded by the non-exciting elements A1 to A6. Preferably, the non-exciting elements A1 to A6 are provided at equal intervals on the circumference of the radius R. Each of the excitation element A0 and the non-excitation elements A1 to A6 are configured to be, for example, a monopole element having a length of about λ / 4 with respect to the wavelength λ of the desired wave, and the radius R is λ / 4. It is configured to be. The feeding point of the excitation element A0 is connected to the circulator 102 via the coaxial cable 5, and the non-excitation elements A1 to A6 are connected to variable capacitance diodes 12-1 to 12-6, respectively. .., X6 change the reactance values x1,..., X6 by setting the reactance value signal from the pointing control unit 103.
[0028]
FIG. 4 is a longitudinal sectional view of the ESPAR antenna device 101. The excitation element A0 is electrically insulated from the ground conductor 11, and each of the non-excitation elements A1 to A6 is grounded to the ground conductor 11 at a high frequency via the variable capacitance diodes 12-1 to 12-6. The operation of the variable capacitance diodes 12-1 to 12-6 will be described. For example, when the longitudinal lengths of the excitation element A0 and the non-excitation elements A1 to A6 are substantially the same, for example, the variable capacitance diodes 12-1 Has inductance (L-type), the variable capacitance diode 12-1 becomes an extension coil, and the electrical length of the non-exciting elements A1 to A6 becomes longer than that of the exciting element A0, thus acting as a reflector. On the other hand, for example, when the variable capacitance diode 12-1 has a capacitance (C characteristic), the variable capacitance diode 12-1 becomes a shortening capacitor, and the electrical length of the non-exciting element A1 becomes shorter than that of the exciting element A0. , Work as a director. The non-exciting elements A2 to A6 connected to the other variable capacitance diodes 12-2 to 12-6 operate in the same manner.
[0029]
Therefore, in the ESPAR antenna device 101, the bias voltage value applied as a control voltage to the variable capacitance diodes 12-1 to 12-6 connected to the respective non-exciting elements A1 to A6 is changed, and the reactance as the junction capacitance value is changed. By changing the values x1,..., X6, the directivity characteristics of the ESPAR antenna device 101 can be changed. The ESPAR antenna device 100 requires only one element to supply power compared to the DBF, and the control voltage is reverse bias and only 10 nA flows through each of the variable capacitance diodes 12-1 to 12-6, which is necessary for control. Since the power is very small, the electronic variable directional antenna can be reduced in size and power consumption.
[0030]
Referring to FIG. 2 again, the traffic monitor unit 105 includes a management control unit 151, a learning sequence signal generator 152, a timer, a memory 153, and a database memory 154 connected to the management control unit 151, respectively. In addition to executing the process of generating the SINR table and the spatial correlation table on the source wireless station side or the receiving wireless station side and the transmission restriction process, the wireless station 1 determines a communication channel to be used in packet communication with another wireless station 1. By transmitting the designated data of the spread code corresponding to the determined communication channel to spread code generator 160 via line control section 106, spread code generator 160 generates a spread code corresponding to the designated data. And the designated data of the time slot corresponding to the determined communication channel is transmitted to the line control unit 1. 6, the transmission timing control unit 141 controls the writing and reading of the communication channel transmission signal data by the transmission buffer memory 142, and the communication channel transmission signal corresponds to the corresponding time slot. Control to be transmitted by
[0031]
Further, the database memory 154 stores a reactance value table, an SINR table, and a spatial correlation table. FIG. 5 is a table showing an example of a reactance value table stored in advance in the database memory 154 of FIG. The maximum value and the minimum value described in the reactance value table of FIG. 5 are the highest values in the movable range of the reactance values x1,..., X6 of the variable capacitance diodes 12-1 to 12-6 loaded on the parasitic elements A1 to A6. Mean value and lowest value. By outputting and setting reactance value signals including bias voltage values corresponding to these reactance values x1,..., X6 to the variable capacitance diodes 12-1 to 12-6 of the ESPAR antenna device 101, the directional characteristics shown in FIG. An antenna directivity pattern as shown in the figure can be obtained. The omni pattern OP is an omnidirectional antenna pattern in a horizontal plane. Sector pattern SP (1) is a sector pattern having a predetermined beam width and having a main beam in the 0-degree direction of azimuth θ (see FIG. 3) of ESPAR antenna apparatus 101, and sector pattern SP (2). Is a sector pattern having the same beam width as the sector pattern SP (1) and having a main beam in the 30-degree direction. Similarly, each of the sector patterns SP (3) to SP (12) has the same beam shape. It is a sector pattern having a width and having different main beam azimuths by 30 each. The twelve sector patterns SP (1) to SP (12) enable the main beam of the ESPAR antenna device 101 to be steered in all azimuth angles.
[0032]
FIG. 6 is a table showing an SINR table stored in the database memory 154 of the wireless station 1-A when the wireless stations 1-B, 1-C and 1-D are present near the wireless station 1-A. is there. This SINR table is transmitted from the wireless station 1-A in the sector patterns SP (1) to SP (12), and is omni-patterned by the wireless stations 1-C, 1-D and 1-B near the wireless station 1-A. It records the SINR value of the radio signal received in the OP. Therefore, the SINR table stores the SINR value, which is the signal quality as viewed from the adjacent wireless stations 1-C, 1-D, and 1-B for each azimuth around the wireless station 1-A, and the corresponding azimuth. Contains. Here, in order to measure the SINR, the BER is measured by transmitting and receiving a data packet (see FIG. 10) having a predetermined training pattern to and from each of the other wireless stations 1, and the BER is measured, and the BER is determined by the modulation / demodulation method of the wireless communication. It is converted to SINR using a graph of BER characteristics with respect to SINR. For example, when the CDMA system is used as shown in FIG. 2, the conversion can be performed using a graph of the BER characteristic with respect to the SINR. For example, when the QPSK differential detection system is used, the conversion can be performed using the graph of the BER characteristic with respect to the CINR. Can be converted. That is, whether to use the carrier power to interference noise power ratio (hereinafter, referred to as CINR) or the SINR depends on the modulation / demodulation method used in the wireless system. Further, by transmitting and receiving a data packet (see FIG. 10) of a predetermined training pattern to and from another wireless station 1 for measuring SINR, by calculating a cross-correlation coefficient between the received signal and the training signal, The SINR can be determined. The cross-correlation coefficient between the received signal and the training signal is a monotonically increasing function with respect to the SINR, and the SINR is uniquely obtained for a certain cross-correlation coefficient. In the present invention, a measured value of received signal quality (signal power or signal power to noise power ratio or the like) relating to co-channel interference noise may be used, and a signal quality table including the measured value may be used.
[0033]
By using this SINR table, for example, as described in Patent Literature 1, when a packet is transmitted to the destination wireless station 1, the wireless station 1 of the first hop is determined based on the SINR table, and the above determination is performed. The packet can be routed by controlling the ESPAR antenna apparatus 101 and transmitting the packet so that a beam is formed for the wireless station 1 at the first hop.
[0034]
FIG. 7 is a table showing a spatial correlation table stored in the database memory 154 of each of the wireless stations 1-A to 1-D when there are five wireless stations 1-A to 1-E. Shows a spatial correlation table of the wireless station 1-A, (b) shows a spatial correlation table of the wireless station 1-B, (c) shows a spatial correlation table of the wireless station 1-C, and (d) shows a wireless correlation table. It is a table | surface which shows the spatial correlation table of station 1-D. For example, the table in FIG. 7A shows that three wireless stations 1-C, 1-D, and 1-B arrive at the wireless station 1-A from the wireless stations 1-C, 1-D, and 1-B. 3 shows a spatial cross-correlation coefficient between the signals. The same applies to the tables in FIGS. 7B, 7C and 7D.
[0035]
First, the spatial correlation value of each wireless station 1 obtained using the ESPAR antenna device 101 will be described. As shown in FIG. 3, since the ESPAR antenna apparatus 101 has only one receiving system, a unique method different from a normal adaptive control type array antenna is required for measuring a spatial correlation value. The omni pattern OP stored in the reactance value table of FIG. 5 and the sector patterns SP (1), SP (3), SP (5), SP (7), SP (9) and SP (11) are used. The reactance value is set in the ESPAR antenna apparatus 101 to generate one omni pattern and six sector patterns having different main beam directions from each other, and the received signal y received by each antenna pattern is generated. _m The cross-correlation coefficient ρ of the received response vector r derived from the set (t) of (t) _s Is calculated using Equation 1 and stored as a spatial correlation value of each wireless station 1. At this time, the received signals need to be individually received one by one.
[0036]
(Equation 1)

[0037]
Where w _m Represents an equivalent weight coefficient (weight) vector (see Non-Patent Document 2), and the steering vectors of the desired wave and the interference wave are respectively represented by a _d And a _i It is written. The superscripts H and * denote Hermitian transpose and complex conjugate, respectively. r _d And r _i Are represented by adding suffixes d and i to the reception response vector r to indicate that they are the reception response vectors of the desired wave and the interference wave, respectively. Receive response vector r = [r ₀ , R ₁ , ..., r ₆ ] ^T Is the received signal sequence y ₀ (T), y ₁ (T), ..., y ₆ The product of (t) and the complex conjugate of the transmission signal u (t) is calculated, and is calculated from its expected value (time average value in a predetermined period).
[0038]
(Equation 2)
r _m = E [y _m (T) u (t) ^* ]
m = 0,1, ..., 6
[0039]
Here, the transmission signal u (t) is a reference obtained by generating the same signal as the signal transmitted from the transmission source wireless station 1 in the learning sequence signal generator 152 of the reception side wireless station 1. Signal.
[0040]
As can be seen from Equation 1, the spatial correlation value of each wireless station 1 acquired by the ESPAR antenna device 101 is a function of the steering vector a (θ) and the reactance values of the variable capacitance diodes 12-1 to 12-6. Therefore, when using the spatial correlation value of each wireless station 1 to determine whether or not interference wave suppression is possible, it is necessary to clarify a set of reactance values as shown in the reactance value table of FIG. In addition, since the spatial correlation value of Equation 1 is normalized to take an absolute value, the channel characteristic h (t) is not included in the spatial correlation value.
[0041]
The received signal y received at the 0th and (2m-1) th antenna patterns (m = 1,..., 6) in the reactance value table of FIG. _m (T) is a (θ) of the steering vector of the ESPAR antenna device 101, h (t) of the propagation path, u (t) of the transmission signal from the wireless station 1 of the transmission source, and n (t) of the thermal noise component. Then, the following expression is obtained.
[0042]
[Equation 3]

[0043]
Here, h (t) is the directivity gain G of the transmitting / receiving antenna. _t , Wave number k, and propagation path length d, represented by the following equation.
[0044]
(Equation 4)

[0045]
The spatial correlation value calculated as described above is recorded in the spatial correlation table in the database memory 154. As is apparent from Equation 1, in order to obtain the spatial correlation table, received signal sequences from two or more adjacent wireless stations are required.
[0046]
FIG. 8 is a directional characteristic diagram showing an example of the directional pattern of the ESPAR antenna device 101 in the wireless station 1-A in FIG. In the example shown in this figure, wireless stations 1-B, 1-C and 1-D are located around wireless station 1-A. When the wireless station 1-A transmits a SETUP signal (see FIG. 10A) indicating that the generation of the SINR table and the spatial correlation table is started, the omni pattern OP is transmitted to the ESPAR antenna according to the reactance value table of FIG. Set in the device 101. When transmitting an RQ (0) signal (see FIG. 10B) following the SETUP signal, a sector pattern SP (1) facing the azimuth angle of 0 degree is set in the ESPAR antenna apparatus 101, and the RQ (0) signal is transmitted. ) Signal is transmitted, the sector pattern SP (2) oriented in the 30-degree direction is set in the ESPAR antenna device 101, and the same applies to the sector pattern SP (330) oriented in the 330-degree direction. ). When the wireless station 1-A receives the RE signal (see FIG. 10B) from the other wireless station 1, the wireless station 1-A further receives the SETUP signal and RQ (0) to RQ from the other wireless station. (330) The omni pattern OP is set in the ESPAR antenna device 101 also when receiving the signal and when transmitting the RE signal.
[0047]
FIG. 9 is a timing chart in the processing of generating the SINR table and the spatial correlation table on the source wireless station side, which is performed between the wireless stations 1-A, 1-B, 1-C, and 1-D in FIG. The wireless station 1-A transmits a SETUP signal for generating the SINR table and the spatial correlation table at an omni pattern OP at random timing. When transmitting a SETUP signal, CSMA is used to avoid collision with other signals. FIG. 10A shows the frame configuration and frame length of the SETUP signal transmitted at this time, FC (Frame Control) defines the frame type of the signal, and D (Duration) corresponds to the frame type and the like. RA (Receiver Address) and TA (Transmitter Address) are addresses indicating a destination wireless station and a source wireless station, respectively, and FCS (Frame Check Sequence) is an error detection by 32-CRC. Used for
[0048]
The wireless stations 1-B, 1-C, and 1-D that are present in the service area of the wireless station 1-A and have received the SETUP signal in the omni pattern OP enter a standby state for the received signal, and the wireless station 1-A And waits for RQ (0) to (330) signals transmitted at known timings. Following the SETUP signal, the wireless station 1-A transmits RQ (0) to (330) signals in sector patterns SP (1) to SP (12), respectively. The RQ (0) to (330) signals are request signals for causing the wireless stations adjacent to the wireless station 1-A to provide data for the SINR table and the spatial correlation table. More specifically, the wireless station 1-A switches 12 sector patterns in 12 directions that differ by 30 degrees in a predetermined time interval and in a predetermined order, and each time the sector pattern is switched, each RQ (0) is switched. To (330) signal is transmitted. In each of the RQ (0) to (330) signals, the azimuth data indicating the main beam azimuth of the sector pattern, and the radio stations 1-B, 1-C, and 1-D indicate the received signal quality (ie, SINR). SEST data, which is a training signal for measurement, is included. The SEST data is a known PN (pseudo noise) signal having the number of symbols Pts. FIG. 10B shows the frame structure and frame length of the RQ (0) signal to the RQ (330) signal. SEST is a signal sequence used to measure the received signal quality (ie, SINR), and SC (Sequence). Control) indicates a packet sequence number and a fragment number, and azimuth data includes sector patterns SP (1) to SP set in the source wireless station 1 when the RQ (0) to RQ (330) signals are transmitted. The azimuth angle of (12) is shown. The FC, D, RA, TA, and FCS signals in the frame are the same as the SETUP signal.
[0049]
The wireless stations 1-B, 1-C and 1-D that have received the SETUP signal transmit the 12 RQ (0) to (330) signals transmitted at a known timing from the wireless station 1-A in the omni pattern OP. The received signal quality for each azimuth is measured based on the received and SEST data portions of the RQ (0) to (330) signals. The received signal quality for each azimuth, that is, the main beam azimuth of the sector patterns SP (1) to SP (12) set at the wireless station 1-A at the time of transmission of the RQ (0) to (330) signals is 0 degree. , 30 degrees,..., 330 degrees. The received signal quality is SINR in the present embodiment, but may be another criterion such as signal strength. Although the RQ (0) to (330) signals are basically received in the omni pattern OP, an adaptive control pattern is formed in the section of SEST data in the signal, and the resulting received signal quality is reduced. You can also get it. The adaptive control pattern is an antenna pattern that changes according to the surrounding environment such as extraneous noise, co-channel interference, or adjacent channel interference, and directs the main beam to the desired signal and nulls to the interference signal. . The radio stations 1-B, 1-C and 1-D transmit the RQ (0) to (330) signals transmitted each time the radio station 1-A switches the 12 sector patterns SP (1) to SP (12). Is temporarily stored in the memory 153 together with the azimuth data indicating the main beam azimuths of the sector patterns SP (1) to SP (12) at the time of transmission.
[0050]
The SINR information for each azimuth obtained by the radio stations 1-B, 1-C, and 1-D is transmitted to each radio station by an RE signal that is a response signal to the RQ (0) to RQ (330) signals. 1-B, 1-C and 1-D are transmitted to the wireless station 1-A. FIG. 10C shows the frame configuration and frame length of the RE signal. In the RE signal, the ESC indicates a plurality of training signals used to calculate the spatial correlation value of each of the radio stations 1-B, 1-C, and 1-D, and a known PN signal having the symbol number Pts is used. It is composed of esc (1) to esc (7) signals repeated seven times. In the RE signal, the SINR table data indicates SINR information corresponding to the main beam azimuths of the sector patterns SP (1) to SP (12) of the transmitting-side radio station 1-A. The FC, D, RA, TA, SC, and FCS signals in the frame are the same as the SETUP signal and the RQ (0) to (330) signals.
[0051]
The antenna pattern of each of the wireless stations 1-B, 1-C and 1-D when transmitting the RE signal is the antenna pattern (omni pattern) when the RQ (0) to (330) signals are received and the SINR is obtained. Or adaptive control pattern). As shown in the frame configuration of FIG. 10C, the RE signals transmitted by the wireless stations 1-B, 1-C, and 1-D have an ESC for use in calculating a spatial correlation value at the beginning of the frame. A signal has been added. When each of the wireless stations 1-B, 1-C and 1-D transmits an RE signal to the wireless station 1-A, collision of each RE signal is avoided by CSMA in the same manner as when transmitting a SETUP signal. Finally, in order to obtain the spatial correlation value by Equation 1, it is necessary that only one wave is received. In this case, the RE signal from each of the wireless stations 1-B, 1-C and 1-D Is avoided by CSMA.
[0052]
In the timing chart illustrated in FIG. 9, the wireless station 1-A first receives an RE signal transmitted from the wireless station 1-C. When the ESC signal included in the RE signal is received, the omni pattern OP and the sector pattern SP (1) are adjusted according to the reactance value table in accordance with the esc (1) to esc (7) signals of known codes that are circulated seven times. , SP (3), SP (5), SP (7), SP (9) and SP (11) are sequentially switched. The esc (1) to esc (7) signals received by each antenna pattern are the received signal sequence y ₀ (T), y ₁ (T), ..., y ₆ This is temporarily stored in the memory 153 as (t).
[0053]
The information of the SINR table data included in the RE signal from the wireless station 1-C is written in the SINR table. The SINR table is assigned a predetermined storage area in the database memory 154, and is written in the order of the wireless stations 1 from which the SINR table data is obtained. When the SINR table data has not been acquired, the storage area of the SINR table is blanked.
[0054]
Next, the wireless station 1-A processes the RE signal transmitted from the wireless station 1-D in the same manner. At this point, the SINR table data of the wireless stations 1-C and 1-D have been written in the SINR table of the wireless station 1-A, and the memory 153 has a Information on received signal sequences of the radio stations 1-C and 1-D is stored.
[0055]
Based on the information of the received signal sequence of each of the wireless stations 1-C and 1-D stored in the memory 153, the wireless station 1-A sets the wireless station 1-C as the desired wave wireless station using Equations 2 and 1. The space between the case where the wireless station 1-D is the interference wave wireless station and the case where the wireless station 1-A is the wireless station 1-D as the desired wave wireless station and the wireless station 1-C is the interference wave wireless station. A correlation table is generated. However, as is clear from Equation 1, the spatial correlation value is the same regardless of which of the two nearby wireless stations is regarded as the desired wave wireless station and the other is regarded as the interference wave wireless station. The spatial correlation table is assigned a predetermined storage area in the database memory 154, and is written in the order of the pair of the wireless station 1 from which the spatial correlation value was obtained. When the spatial correlation value has not been obtained, the storage area of the spatial correlation table is blanked.
[0056]
Next, the wireless station 1-A receives the RE signal transmitted from the wireless station 1-B, similarly generates an SINR table, and further, the wireless station 1-A sets the wireless station 1-B to the desired wave wireless station. When the wireless station 1-C is an interference wave wireless station, or when the wireless station 1-A is the wireless station 1-C as a desired wave wireless station and the wireless station 1-B is an interference wave wireless station, The spatial correlation value is calculated for all combinations of the wireless stations 1 that have received the RE signal so far, and a spatial correlation table is generated.
[0057]
Based on the SINR table and the spatial correlation table created in this way, the relative position of the surrounding wireless station 1 and the state of the radio wave environment between the wireless stations 1 can be grasped, so that an optimal route can be selected. In addition, SDMA that limits transmission in the direction in which the communicating wireless station 1 is located and establishes communication between a plurality of sets of user terminals simultaneously can be performed. As described above, not only the SINR table is generated using the same signal as the signal for generating the SINR table according to the conventional example, but also the spatial correlation table can be generated at the same time. By controlling the wireless network without increasing the amount of communication required to generate each table, the throughput of the wireless network can be increased.
[0058]
In the communication device configured as described above, when performing wireless communication with the first wireless station that transmits a desired wave, when the calculated spatial correlation coefficient is equal to or greater than a predetermined threshold, interference is transmitted. Transmission restriction is performed by transmitting a transmission restriction request signal to the second wireless station, and after terminating wireless communication with the first wireless station, transmitting a transmission restriction release signal to the second wireless station. To release the transmission restriction.
[0059]
As described above, according to the present embodiment, the spatial correlation table can be generated at the same time as the generation of the SINR table without transmitting and receiving a special signal, and the interference wave is transmitted based on the spatial correlation table. Transmission restriction can be performed on the radio station that performs the transmission. As a result, in a wireless network such as an ad hoc wireless network, transmission restriction can be appropriately performed, and a decrease in throughput of the entire wireless network can be prevented.
[0060]
<Second embodiment>
Hereinafter, a communication device for a wireless network according to the second embodiment of the present invention will be described. In the first embodiment, the SINR table and the spatial correlation table are generated in the wireless station 1 that transmits the SETUP signal. In the second embodiment, the SINR table and the spatial correlation table are generated in the wireless station 1 that receives the SETUP signal. And a spatial correlation table are generated, so that the amount of communication required to generate each table can be reduced.
[0061]
FIG. 11 is a directional pattern diagram showing an example of a directional pattern set in the ESPAR antenna apparatus 101 in the processing of generating the SINR table and the spatial correlation table on the receiving wireless station side according to the second embodiment of the present invention. In the example shown in this figure, there are five wireless stations 1-A to 1-E. The three wireless stations 1-A, 1-B, and 1-D are located at positions where the other two wireless stations 1 can receive the signal when the other two wireless stations 1 transmit the omni pattern OP. When the wireless stations 1-A, 1-B, 1-D, and 1-E have an omni pattern, and the wireless station 1-C itself has an omni pattern, the wireless station 1-A and the wireless station 1-A It is located at a position where the signal 1-E can be received.
[0062]
When transmitting a SETUP / RQSC signal (see FIG. 13) for generating the SINR table and the spatial correlation table, each wireless station 1 sets the omni pattern OP to the ESPAR antenna device 101 according to the reactance value table of FIG. I do. On the other hand, each wireless station 1 sets the omni pattern OP to the ESPAR antenna apparatus 101 when receiving the transmitted SETUP signal, but when receiving the esc (1) signal in the RQSC signal following the SETUP signal, When the sector pattern SP (1) in which the main beam azimuth is oriented in the direction of 0 degrees is set in the ESPAR antenna apparatus 101 and the esc (2) signal following the esc (1) signal is transmitted, the main beam azimuth is The sector pattern SP (2) oriented in the direction of 30 degrees is set in the ESPAR antenna device 101, and similarly, the sector pattern SP (330) in which the main beam azimuth angle is oriented in the direction of 330 degrees is similarly set. When each wireless station 1 receives the esc (13) signal following the esc (12) signal, the omni pattern OP is set in the ESPAR antenna apparatus 101 again.
[0063]
FIG. 12 is a process of generating the SINR table and the spatial correlation table on the receiving wireless station side, which is performed between the wireless stations 1-A, 1-B, 1-C and 1-D in the second embodiment according to the present invention. 6 is a timing chart in FIG. The wireless station 1-A transmits a SETUP / RQSC signal at an omni pattern OP at random timing. For transmitting the SETUP / RQSC signal, CSMA is used to avoid collision with other signals. FIG. 13 is a diagram showing a frame configuration and a frame length of the SETUP / RQSC signal transmitted at this time. The meanings of the data FC, D, RA, TA, and FCS included in the SETUP signal are the same as in the first embodiment (see FIG. 10). The RQSC signals are a plurality of training signals used for calculating a spatial correlation value of each wireless station 1, and each of the esc (1) to esc (13) signals including known PN signals having a predetermined number of symbols Pts. It is composed of
[0064]
The wireless stations 1-B, 1-C, and 1-D that are present in the service area of the wireless station 1-A and have received the SETUP signal in the omni pattern OP enter a standby state for the received signal, and the wireless station 1-A From the RQSC signal transmitted at a known timing.
[0065]
Following the SETUP signal, the wireless station 1-A transmits the RQSC signal in an omni pattern OP at a predetermined length and interval. The RQSC signal is composed of 13 repetitions of the esc signal having the number of symbols Pts as described above. The wireless stations 1-B, 1-C, and 1-D that are in a standby state after receiving the SETUP signal are sent from the wireless station 1-A at known timings, from esc (1) to esc (12). The twelve sector patterns SP (1) to SP (12) are switched in accordance with the signal to sequentially receive the esc (1) to esc (12) signals, and the sector patterns SP (1) to SP (12). , The received signal quality (for example, SINR) for each of the angles is measured, and an SINR table for the wireless station 1-A is generated. The esc (13) signal is received in the omni pattern OP, but is not used for generating the SINR table.
[0066]
As in the present embodiment, the SINR table generated on the receiving wireless station 1 side is different from the SINR table in the first embodiment (see FIG. 7) and is transmitted from a wireless station adjacent to a certain wireless station 1. , The SINR value of the radio signal received by the radio station 1 is recorded. Accordingly, in the present embodiment, the SINR table of the wireless station 1-A and the SINR values of the wireless stations 1-C, 1-D, and 1-B adjacent to the wireless station 1-A include The SINR values of the radio signals transmitted from the stations 1-C, 1-D and 1-B and received by the radio station 1-A are recorded for each azimuth at the time of the reception.
[0067]
A spatial correlation table is also generated using the esc (1) to esc (13) signals received as described above. The wireless stations 1-B, 1-C, and 1-D transmit the sector patterns SP (1), SP (3), SP (5), SP (7), SP (9) in the received SETUP / RQSC signal. And esc (1), esc (3), esc (5), esc (7), esc (9) and esc (11) received by the SP (11). ₁ (T), ..., y ₆ (T) is stored in the memory 153. The thirteenth esc signal is received in the omni pattern OP, and the received signal y ₀ (T) is stored in the memory 153.
[0068]
After the wireless station 1-A transmits the SETUP / RQSC signal, the wireless station 1-B then transmits the SETUP / RQSC signal, and the wireless stations 1-A, 1-C, and 1-D operate in the same manner as above. , Esc (1) to esc (12), generate an SINR table for the wireless station 1-B, and esc (1), esc (3), esc (5), esc (7), esc (9). ), Esc (11) and esc (13) signals, the received signal sequence y of the wireless station 1-B. ₀ (T), ..., y ₆ (T) is acquired and stored in the memory 153 of each wireless station 1.
[0069]
At this point, the radio stations 1-C and 1-D have stored the received signal sequences of the radio stations 1-A and 1-B in the memory 153. 1 can be used to calculate the spatial correlation value between the wireless stations 1-A and 1-B. Each of the wireless stations 1-C and 1-D calculates a spatial correlation value, generates a result as a spatial correlation table, and stores it in the database memory 154. Similarly, the wireless stations 1-C and 1-D transmit SETUP / RQSC signals while preventing collisions in CSMA, and the other wireless stations 1 receiving the signals generate SINR tables and spatial correlation tables. Stored in the database memory 154.
[0070]
Similarly, the wireless stations 1-A, 1-B, 1-C, and 1-D sequentially transmit SETUP / RQSC signals at a certain timing of each wireless station while avoiding collision by CSMA, The wireless station 1 that has received the SETUP / RQSC signal generates an SINR table, and the wireless station 1 that has received the SETUP / RQSC signal transmitted from two different wireless stations 1 uses space 2 and equation 1 Generate a correlation table.
[0071]
As described above, the SINR table and the spatial correlation table are generated in each wireless station 1 by all the wireless stations 1 periodically transmitting the SETUP / RQSC signal at a certain fixed period. For example, after turning on the power, a certain period may be a period for generating this table, and a method that allows communication after that may be used.
[0072]
The processing of generating the SINR table and the spatial correlation table described in the first embodiment uses the RE signal responding to the RQ (0) to RQ (330) signals from the transmitting wireless station 1 to transmit the SINR table and the spatial correlation table. Is a method of sequentially generating an SINR table and a spatial correlation table. Therefore, there is an advantage that information of all the wireless stations 1 that have received the SETUP signal is collected at the transmitting wireless station 1. However, the SETUP signal, the RQ (0) to RQ (330) signals, and the RE signal are There is a reciprocating motion between them. In the second embodiment, since only the SETUP / RQSC signal is transmitted from one wireless station 1 to another wireless station 1, the required communication amount is reduced as compared with the first embodiment. Can be.
[0073]
FIG. 14 is a timing chart showing an example of the transmission restriction process using the spatial correlation table generated according to the first or second embodiment and stored in the database memory 154. In this embodiment, in an ad hoc wireless network in which five wireless stations 1-A to 1-E exist as shown in FIG. 11, the transmission restriction processing is executed with reference to the spatial correlation table of FIG. Each of the wireless stations 1-A, 1-B and 1-D is located at a position where the signal can be received when the other two wireless stations 1 transmit the omni pattern OP. When the wireless stations 1-A, 1-B, 1-D, and 1-E have an omni pattern, and the wireless station 1-C itself has an omni pattern, the wireless station 1-A and the wireless station 1-A It is located at a position where the signal 1-E can be received. This ad hoc wireless network can be configured based on the IEEE802.11b standard of the wireless LAN.
[0074]
The wireless station 1-C starts communication with the wireless station 1-A. First, the wireless station 1-C transmits an RTS (Request to send) signal to the wireless station 1-A in the omni pattern OP. Before transmitting the RTS signal, the wireless station 1-C refers to its spatial correlation table, and the wireless station whose spatial correlation value with the wireless station 1-A is equal to or greater than a predetermined threshold (for example, 0.9). Check for the presence of 1. For the radio station 1 (referred to as a regulated station) whose spatial correlation value exceeds the threshold value, the transmission restriction start request signal is added to the RTS signal and transmitted. In the case of FIG. 7C, there is no regulated station.
[0075]
The wireless station 1-A receives the RTS signal from the wireless station 1-C, and transmits a CTS (Clear to send) signal for the wireless station 1-A to the wireless station 1-C. Before transmitting the CTS signal, the wireless station 1-A refers to its spatial correlation table and checks whether there is a terminal whose spatial correlation value with the wireless station 1-C is equal to or larger than a threshold. For the radio station 1 whose spatial correlation value exceeds the threshold value, a transmission restriction start request signal is added to the CTS signal and transmitted. In the case of FIG. 7A, the regulated station is the wireless station 1-B.
[0076]
Upon receiving the CTS signal, the wireless station 1-C starts transmitting data to the wireless station 1-A. Each time the wireless station 1-A receives the DATA1, DATA2,..., DATAn signals as data from the wireless station 1-C, it transmits ACK1, ACK2,. . When the transmission source radio station 1-C transmits a transmission restriction start request signal to any of the interference wave radio stations 1, after transmitting the last data DATAn signal and receiving an acknowledgment ACKn signal corresponding thereto, A restriction release request signal is transmitted to the same interference wave radio station 1 to release the transmission restriction. When transmitting the transmission restriction start request signal to the interference wave radio station 1, the destination radio station 1-A transmits a restriction release request signal to the same interference wave radio station 1 after transmitting the last acknowledgment ACKn signal. Send to cancel outgoing call barring.
[0077]
The wireless stations 1-B, 1-D, and 1-E that have received the RTS signal transmitted by the wireless station 1-C and the CTS signal transmitted by the wireless station 1-A are the wireless stations 1-A and 1-E. -C, it is confirmed by the addresses of the source radio station and the destination radio station included in the RTS signal and the CTS signal, and the transmission restriction start request signal addressed to the own station is included in the RTS signal and the CTS signal. Check whether it is included. If the transmission restriction start request signal addressed to the own station is included in the RTS signal and the CTS signal, a predetermined timeout period elapses after the transmission restriction start request signal is received, or the transmission restriction start request signal is transmitted. Until the wireless station 1 receives the restriction release request signal transmitted by the same wireless station 1, the wireless station restricts the transmission so as not to radiate radio waves serving as interference waves to the wireless stations 1-C and 1-A. . When the transmission restriction start request signal addressed to the own station is not included in the RTS signal and the CTS signal, the transmission can be performed even if the RTS signal or the CTS signal is received.
[0078]
By transmitting the transmission restriction start request signal only to the radio station 1 that needs to be truly restricted by using the spatial correlation value in such a procedure, the RTS signal and the CTS signal are transmitted as in the related art. Avoiding a situation in which all the wireless stations 1 that have received the STA cannot transmit, reducing the possibility of the presence of hidden terminals, and also reducing the number of wireless stations 1 whose transmission is restricted despite the possibility of SDMA. As a result, it is expected that the throughput of the entire network will be improved.
[0079]
In the embodiment according to the present invention, an SINR table is generated using twelve sector patterns SP (1) to SP (12), and six sector patterns SP (1), (3), (5), (5). 7), (9) and (11) and the omni pattern OP are used to generate the spatial correlation table. However, it is not possible to generate each table using a different number and / or shape of antenna patterns. It will be obvious.
[0080]
In the above embodiment, a MAC (Media Access Control) communication method using a spatial correlation value measured by controlling the reactance of an ESPAR antenna in a stage prior to the communication by the ad hoc wireless network has been proposed. The method according to the first embodiment that measures the spatial correlation value without changing the sequence of the SINR table method proposed in the conventional example, and the new second embodiment that generates the spatial correlation table on the receiving wireless station side Such a scheme is shown, and it is possible to prevent the occurrence of interference waves that cannot be prevented by adaptive control, and to reduce the number of wireless stations whose transmission is restricted despite SDMA is possible.
[0081]
【The invention's effect】
As described in detail above, according to the method for controlling a wireless network according to the present invention, a communication method and a communication apparatus for a wireless network including a plurality of wireless stations and performing wireless communication between the wireless stations include: The radio signal of the desired wave from the first radio station is received using a plurality of radiation patterns having different directional characteristics of the array antenna capable of changing the respective reception signals, and the received signals and the transmitted signal are received. A reception response vector r of a desired wave having the same reference signal as an element _d , And receives a radio signal of an interference wave from the second radio station using a plurality of radiation patterns of the array antenna, and converts each of the received signals and a reference signal identical to a signal to be transmitted. Reception response vector r of the interference wave as an element _i , And the reception response vector r of the desired wave _d And the reception response vector r of the interference wave _i And calculating a spatial correlation coefficient between the desired wave and the interference wave based on the above, and when performing wireless communication with the first wireless station, the calculated spatial correlation coefficient is a predetermined threshold value. If so, a transmission restriction request signal is transmitted to the second wireless station. Therefore, in a wireless network such as an ad hoc wireless network, transmission restriction can be appropriately performed, and a decrease in throughput of the entire wireless network can be prevented.
[Brief description of the drawings]
FIG. 1 is a plan layout view of a plurality of wireless stations 1-A to 1-I configuring an ad hoc wireless network according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing an internal configuration of each wireless station 1 of FIG.
FIG. 3 is a perspective view showing a configuration of the ESPAR antenna device 101 of FIG.
FIG. 4 is a longitudinal sectional view of the ESPAR antenna device 101 of FIG.
FIG. 5 is a table showing an example of a reactance value table stored in advance in a database memory 154 of FIG. 2;
FIG. 6 is a table showing an SINR table stored in a database memory 154 of FIG. 2;
7 is a table showing a spatial correlation table stored in a database memory 154 of FIG. 2, wherein (a) shows a spatial correlation table of the wireless station 1-A and (b) shows a spatial correlation table of the wireless station 1-B; 7 shows a correlation table, (c) shows a spatial correlation table of the wireless station 1-C, and (d) shows a spatial correlation table of the wireless station 1-D.
8 is a directional pattern diagram showing an example of a directional pattern of the ESPAR antenna device 101 in the wireless station 1-A in FIG.
FIG. 9 is a timing chart in a process of generating an SINR table and a spatial correlation table on the source wireless station side, which is performed between the wireless stations 1-A, 1-B, 1-C, and 1-D of FIG.
10 is a signal format diagram showing a frame configuration and a frame length of each signal transmitted and received between each wireless station 1 in FIG. 1 for generating a SINR table and a spatial correlation table on a source wireless station side; (A) shows a SETUP signal, (b) shows RQ (0) to RQ (330) signals, and (c) shows an RE signal.
FIG. 11 is a directional pattern diagram showing an example of a directional pattern set in the ESPAR antenna apparatus 101 in the processing of generating the SINR table and the spatial correlation table on the receiving wireless station side according to the second embodiment of the present invention.
12 is a timing chart in an SINR table and a spatial correlation table generation process on the receiving wireless station side, which is performed between the wireless stations 1-A, 1-B, 1-C, and 1-D in FIG. 11;
13 is a signal format diagram showing a frame configuration and a frame length of each signal for processing of generating an SINR table and a spatial correlation table on a receiving wireless station side, which is executed between each wireless station 1 in FIG. 11;
FIG. 14 is a timing chart showing an embodiment of a transmission restriction process executed using the spatial correlation table of FIG. 7;
[Explanation of symbols]
1, 1-A to 1-I: radio station,
101: ESPAR antenna device,
102: circulator,
103 ... pointing control unit,
104: Packet transmitting / receiving unit
105: traffic monitor unit
106 ... line control unit,
107: Upper layer processing device,
130 ... Packet receiving unit,
131 ... high frequency receiver,
132 demodulator,
133: reception buffer memory,
140 ... packet transmitting unit,
141: transmission timing control unit,
142 transmission buffer memory,
143: modulator,
144: high frequency transmitter,
151 management and control unit
152: learning sequence signal generator
153 ... memory,
154: database memory,
160 ... Spreading code generator.

Claims (12)

A communication method for a wireless network including a plurality of wireless stations and performing wireless communication between the wireless stations,
Radio signals of a desired wave from the first radio station are respectively received by using a plurality of radiation patterns having different directivity characteristics of an array antenna whose directional characteristics can be changed, and the received signals and the received signals are transmitted. obtains a reception response vector r _d of desired waves and signals same reference signal as elements, the radio signal of the interference wave from the second radio station using a plurality of radiation pattern of the array antenna receiving respectively, and each received signal the received, obtains the reception response vector r _i of the interference wave to the same reference signal and the signal transmitting element, a receiving response vector r _d of the desired wave, the reception response of the interference wave a step of based on the vector r _i, to calculate the spatial correlation coefficient between the desired wave and the interference wave,
Transmitting a transmission restriction request signal to the second wireless station when the calculated spatial correlation coefficient is equal to or greater than a predetermined threshold when performing wireless communication with the first wireless station; And a communication method for a wireless network. Transmitting a transmission restriction request signal to the second wireless station and terminating the wireless communication with the first wireless station, and then transmitting a transmission restriction release signal to the second wireless station. The communication method for a wireless network according to claim 1, further comprising: The step of calculating the spatial correlation coefficient includes receiving, in response to a request signal from each of the wireless stations, a wireless signal from each of the wireless stations, which is transmitted using a plurality of radiation patterns of the array antenna. The communication method for a wireless network according to claim 1 or 2, wherein a spatial correlation coefficient between each wireless station is calculated. The step of calculating the spatial correlation coefficient includes the steps of: receiving a radio signal from each of the radio stations transmitted periodically using a plurality of radiation patterns of the array antenna to form a space between the radio stations; 3. The communication method for a wireless network according to claim 1, wherein a correlation coefficient is calculated. The plurality of radiation patterns include an omni pattern having omnidirectional characteristics and a plurality of sector patterns having a predetermined beam width and different beam directions. A communication method for a wireless network according to any one of the preceding claims. The array antenna includes an excitation element for transmitting and receiving a radio signal, a plurality of non-excitation elements provided at a predetermined distance from the excitation element, and a plurality of variable elements respectively connected to the plurality of non-excitation elements. A reactance element, and by changing the reactance value of each of the variable reactance elements, the plurality of non-excitation elements operate as a director or a reflector, respectively, thereby changing a directional characteristic of the array antenna. A communication method for a wireless network according to any one of claims 1 to 5. A communication device for a wireless network including a plurality of wireless stations and performing wireless communication between the wireless stations,
Radio signals of a desired wave from the first radio station are respectively received by using a plurality of radiation patterns having different directivity characteristics of an array antenna whose directional characteristics can be changed, and the received signals and the received signals are transmitted. obtains a reception response vector r _d of desired waves and signals same reference signal as elements, the radio signal of the interference wave from the second radio station using a plurality of radiation pattern of the array antenna receiving respectively, and each received signal the received, obtains the reception response vector r _i of the interference wave to the same reference signal and the signal transmitting element, a receiving response vector r _d of the desired wave, the reception response of the interference wave based on the vector r _i, a calculating means for calculating a spatial correlation coefficient between the desired wave and the interference wave,
Control for transmitting a transmission restriction request signal to the second wireless station when the calculated spatial correlation coefficient is equal to or greater than a predetermined threshold when performing wireless communication with the first wireless station; And a communication device for a wireless network. The control means transmits a transmission restriction request signal to the second radio station, and after terminating radio communication with the first radio station, transmits a transmission restriction release signal to the second radio station. The communication device for a wireless network according to claim 7, wherein the communication device transmits: The calculating means receives a radio signal from each of the radio stations, which is transmitted using a plurality of radiation patterns of the array antenna in response to a request signal from each of the radio stations. The communication device for a wireless network according to claim 7 or 8, wherein a spatial correlation coefficient between stations is calculated. The calculating means calculates a spatial correlation coefficient between the respective wireless stations by receiving the periodically transmitted wireless signals from the respective wireless stations using the plurality of radiation patterns of the array antenna. The communication device for a wireless network according to claim 7 or 8, wherein: 11. The method according to claim 7, wherein the plurality of radiation patterns include an omni pattern having an omnidirectional characteristic and a plurality of sector patterns having a predetermined beam width and different beam directions. A communication device for a wireless network according to any one of the preceding claims. The array antenna includes an excitation element for transmitting and receiving a radio signal, a plurality of non-excitation elements provided at a predetermined distance from the excitation element, and a plurality of variable elements respectively connected to the plurality of non-excitation elements. A reactance element, and by changing the reactance value of each of the variable reactance elements, the plurality of non-excitation elements operate as a director or a reflector, respectively, thereby changing a directional characteristic of the array antenna. A communication device for a wireless network according to any one of claims 7 to 11.

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