JP2004120533A

JP2004120533A - System and device for controlling antenna

Info

Publication number: JP2004120533A
Application number: JP2002283156A
Authority: JP
Inventors: Seiji Harada; 原田　政治; Yuji Hayashino; 林野　裕司; Shoichi Nishino; 西野　正一; Yoshitaka Ota; 太田　良隆; Yasuo Hamamoto; 浜本　康男; Yasunori Okada; 岡田　恭典; Shuichi Sato; 佐藤　修一
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2002-09-27
Filing date: 2002-09-27
Publication date: 2004-04-15

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that communication breaks off as a result accompanying a decrease in received electric field strength or an increase in a data receiving error rate due to an environment with many obstacles as in a house and a change in a communication environment caused by the movement, etc., of people around a radio communication terminal in transmission of video and data by using a radio communication system. <P>SOLUTION: When the received electric field strength drops or the data receiving error rate rises, a radio receiving terminal can obtain an optimum receiving state even in the environment with many obstacles by controlling the turning of a directional antenna to a position where an optimum received signal level can be obtained or transmitting a control signal to a radio transmitter and controlling the turning of the directional antenna of the radio transmitter if the radio receiver obtains only a received signal level that is not higher than a prescribed threshold level. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は送信局と受信局の間で映像などのストリームデータや大容量のデータ通信を行う無線通信システムにおいて、受信局が受信誤りの少ない最適な受信状態を得られるようにアンテナを回転制御するためのアンテナ制御方式に関するものである。
【０００２】
【従来の技術】
従来のアンテナ制御方式としては基地局側のアンテナとして指向性アンテナを用いて回転制御させ、端末局側のアンテナとして無指向性アンテナを用いる構成が一般的であった（例えば、特許文献１参照）。
【０００３】
図５は従来のアンテナ制御方式の構成を示すブロック図である。
【０００４】
図５において、３０は基地局、４０は端末局の構成を示している。
【０００５】
基地局３０は、３０１は指向性アンテナ、３０２は指向性アンテナで受信した信号と指向性アンテナ１０１を介して受信局へ送信する信号を分離するスイッチ手段、３０３は送信データを変調して無線周波数の送信信号を生成する信号送信手段、３０４は受信信号を復調して受信データを生成する信号受信手段、３０５は受信信号の受信電力レベルを検出する信号レベル検出手段、３０６は受信電力レベルに応じてアンテナ制御を行うアンテナ制御手段、３０７は指向性アンテナ３０１を回転させるアンテナ駆動手段により構成される。
【０００６】
端末局４０は、４０１は無指向性アンテナ、４０３は送信データを変調して無線周波数の送信信号を生成する信号送信手段、４０４は受信信号を復調して受信データを生成する信号受信手段により構成される。
【０００７】
以上のように構成された従来の基地局３０及び端末局４０において、データ通信を行う方法について説明する。
【０００８】
基地局３０は送信データを信号送信手段３０３で無線周波数の送信信号に変調し、指向性アンテナ３０１を介して端末局４０へ送信する。端末局４０は無指向性アンテナ４０１で基地局３０の送信信号を受信し、信号受信手段で復調して、受信データを出力する。
【０００９】
逆に、端末局４０は送信データを信号送信手段で変調し、無指向性アンテナ４０１を介して基地局３０へ送信する。基地局３０は指向性アンテナ３０１で端末局４０の送信信号を受信すると信号受信手段で復調して受信データを出力する。
また、同時に信号レベル検出手段で受信信号の受信電力レベルを検出する。
【００１０】
アンテナ制御手段３０６は受信信号レベルが所定レベル低下した場合にアンテナ駆動手段３０７を制御し、指向性アンテナ３０１を回転させることで受信信号レベルが低下しないようにしている。
【００１１】
本構成によって、端末局４０が移動して基地局３０の信号レベル検出手段３０５で検出される受信電力レベルが低下した場合に指向性アンテナ３０１を回転制御することで受信信号レベルが低下しないようにすることができる。
【００１２】
【特許文献１】
特開平０９−３２１６７７
【００１３】
【発明が解決しようとする課題】
しかしながら、映像などの大容量のデータを高速伝送するためには、使用できる周波数帯域が広いミリ波帯を使用する必要がある。例えば、５ＧＨｚ帯や２５ＧＨｚ帯、あるいは６０ＧＨｚ帯といった周波数帯を使用すれば、数十Ｍビット／秒以上の伝送速度で通信することが可能であり、映像などのストリームデータをＤＶ（Ｄｉｇｉｔａｌ　Ｖｉｄｅｏ）規格やＭＰＥＧ２規格で伝送することが可能である。
【００１４】
ところが、これらの周波数帯は電波の直進性が強いため、宅内のような障害物が多い場所では伝送性能が大きく劣化してしまう。また、波長が短いことから壁などで反射した反射波が直接波に重なり合うことにより発生するマルチパスフェージングが、低い周波数帯を使用する場合と比較し頻繁に発生し、信号を正常に受信できず、受信誤りが発生する。
【００１５】
特に、無指向性アンテナを用いることで、あらゆる方向からの反射波を受信することになり、人が歩き回るといった行動をした場合には周辺の反射波の状況が変化し、マルチパスフェージングが頻繁に発生することになる。
【００１６】
これを避けるために、単純に端末局側も指向性アンテナを使用すると、端末のすぐ前に障害物が配置されているような場合には同様に信号の受信電力レベルが劣化して、受信誤りが発生する。
【００１７】
【課題を解決するための手段】
前記従来の課題を解決するために、本発明のアンテナ制御方式は、送信局及び受信局とも指向性アンテナを備え、受信局側で検出した受信信号レベルに応じて受信局の指向性アンテナを回転制御して、最大の受信電力レベルが得られる位置にアンテナを配置するとともに、所定の受信電力レベルが得られない場合には、送信局へアンテナ制御信号を送信し、送信局の指向性アンテナを受信局側から回転制御して、送信局の指向性アンテナを最大の受信電力レベルが得られる位置に配置する構成としたものである。
【００１８】
本構成によって、送信局及び受信局双方の指向性アンテナを回転制御することにより、受信電力レベルが最大の位置に指向性アンテナを配置することができる。
【００１９】
【発明の実施の形態】
以下、本発明の実施の形態について、図面を参照しながら説明する。
【００２０】
（実施の形態１）
図１は、本発明の実施の形態１における送信局及び受信局の構成を示すブロック図である。図１において、１０は送信局、２０は受信局で、送信局から受信局に対して映像やデータを送信する。
【００２１】
送信局１０において、１０１は指向性アンテナ、１０２は指向性アンテナで受信した信号と指向性アンテナ１０１を介して受信局へ送信する信号を分離するスイッチ手段、１０３は送信データを変調して無線周波数に変換し送信信号を生成する信号送信手段、１０４はスイッチ手段１０２で分離した受信信号の受信処理を行う信号受信手段、１０５は信号受信手段１０４で受信した制御信号に従ってアンテナ駆動手段１０６を制御するアンテナ制御手段、１０６はアンテナ制御手段１０５の制御に従って指向性アンテナ１０１を回転させるアンテナ駆動手段である。
【００２２】
受信局２０において、指向性アンテナ１０１、スイッチ手段１０２、アンテナ駆動手段１０６は送信局１０と同等の構成である。１０７はスイッチ手段１０２で分離した受信信号の受信処理を行い、受信データを生成する信号受信手段、１０８は受信信号の受信電力レベルを検出する信号レベル検出手段、１０９は受信電力レベルに応じてアンテナ駆動手段１０６にアンテナ制御信号を出力するとともに、送信局のアンテナを制御するための制御データを生成するアンテナ制御手段、１１０はアンテナ制御手段１０９で生成した制御データを変調して無線周波数に変換し送信信号を生成する制御信号送信手段である。
【００２３】
以上のように構成した送信局および受信局の動作について詳細に説明する。
【００２４】
まず、送信局１０の信号送信手段１０３には送信データが入力される。この送信データはインターネットデータや映像や音声をＭＰＥＧなどのストリームフォーマットに圧縮したデジタルデータである。信号送信手段１０３は送信データにデジタル変調を施し、受信局で送信データを正しく受信するために必要な情報をプリアンブルとしてデジタル変調を施した送信データフレームごとその先頭に付加し、無線伝送する周波数帯の送信信号に変換する。ここで、デジタル変調方式としてはＱＰＳＫなどの位相変調や直交振幅変調（ＱＡＭ）、あるいはこれらの変調方式と組み合わせてスペクトラム拡散や直交周波数分割多重（ＯＦＤＭ）などが用いられる。また、プリアンブルには無線周波数を補正するために必要な情報や変調方式に関する情報などが含まれる。
【００２５】
信号送信手段１０３で生成された送信信号はスイッチ手段１０２から指向性アンテナ１０１へ送られ、受信局２０の指向性アンテナ１０１に送信される。指向性アンテナ１０１にはアンテナ面の前方方向への指向性を有する指向性アンテナを用いる。宅内のような障害物の多い環境や人の動きによる電波の変動が多い環境でダイポールアンテナのような無指向性のアンテナを用いると、電波の到来方向が複雑に変化し、受信電力レベルが大きく変化して信号受信手段１０７での復調処理やアンテナの制御方法が困難になるためである。
【００２６】
受信局２０は送信局１０から送信された送信信号を指向性アンテナ１０１で受信すると、スイッチ手段１０２を介して信号受信手段１０７及び信号レベル検出手段１０８へ送られる。
【００２７】
信号受信手段１０７は、受信信号のプリアンブルの情報に従って復調するための無線周波数を補正し、受信信号を復調して元の受信データを再生する。
【００２８】
信号レベル検出手段１０８は受信信号の電力を測定する。受信電力の測定方法としては、
１）受信信号をフレーム単位でフレーム全体の電力の平均値を求める
２）受信信号のプリアンブルの電力を求める
方法がある。
【００２９】
さらに、上記２つの方法を複数フレームの受信電力値を保持し、所定フレーム数ごとにその受信電力値を平均化して受信電力を求めてもよい。複数フレームの電力を平均化することで瞬時的な受信電力の変動を抑えることができる。特に多値変調を用いる場合は変調後の振幅が一様でないため、フレームごとの受信電力にもともとばらつきがある。したがって、複数フレームの受信電力を平均化する方が良い。
【００３０】
信号レベル検出手段１０８は上記の方法のいずれかにより検出した受信信号レベルをアンテナ制御手段１０９に出力する。
【００３１】
アンテナ制御手段１０９は、信号受信手段１０７において受信信号の受信電力レベルが低すぎるために受信データの再生が不可能になる受信電力レベルの閾値を保持しておき、受信信号の受信電力レベルが所定の閾値以下になった場合にアンテナ駆動手段１０６にあらかじめ定めた方向に指向性アンテナ１０１を所定の角度回転させる回転指示信号を送る。
【００３２】
アンテナ駆動手段１０６は軸を中心に指向性アンテナ１０１を回転させて指向方向を変化させる。
【００３３】
次にアンテナの回転制御方法についてはいくつかの方法があり、それぞれ詳細に説明する。
【００３４】
まず、アンテナ回転制御を行う第１の方法について説明する。
【００３５】
アンテナ制御手段１０９は指向性アンテナ１０１をあらかじめ定めた方向に所定の角度回転させて停止し、信号レベル検出手段１０８で受信電力レベルを検出する。その結果、受信電力レベルが所定の閾値レベル以上になった場合にはそのアンテナ位置でアンテナの回転制御を完了する。
【００３６】
しかし、所定の閾値以上の受信電力レベルが得られなかった場合にはさらに所定の角度回転させ、これを繰り返すことで所定の閾値レベル以上になった場合にはそのアンテナ位置でアンテナの回転制御を完了する。
【００３７】
また、所定の角度回転させる回数をあらかじめ定めておき、定めた回数アンテナを回転させた所で、所定の閾値レベル以上の受信電力レベルが得られなかった場合には、最初のアンテナ位置から反対の方向へ所定の角度アンテナを回転させる。その後、所定の閾値以上の受信電力レベルが得られたアンテナ位置でアンテナの回転制御を完了する。
【００３８】
なお、上記の方法では受信電力レベルが、所定の閾値レベル以上になった場合にアンテナの回転制御を完了したが、過去の受信電力レベルの記録からその平均値を求め、その平均値から所定の割合以上の受信電力レベルが得られた場合に、そのアンテナ位置でアンテナの回転制御を完了してもよい。
【００３９】
次に、アンテナ回転制御を行う第２の方法について説明する。
【００４０】
アンテナ制御手段１０９はアンテナをあらかじめ定めた方向に所定の角度回転させる間、信号レベル検出手段１０８で検出した受信信号レベルとそのアンテナ位置を記録し、所定の角度まで回転させる。このアンテナを回転する間得られた受信信号レベルの最大値が所定の閾値レベル以上であった場合に、その最大値が得られたアンテナ位置までアンテナを回転させ、そのアンテナ位置でアンテナの回転制御を完了する。
【００４１】
しかし、所定の閾値以上の受信電力レベルが得られなかった場合にはさらに所定の角度回転させ、これを繰り返すことで所定の閾値レベル以上になった最大の受信電力レベルのアンテナ位置でアンテナの回転制御を完了する。
【００４２】
また、所定の角度回転させる回数をあらかじめ定めておき、定めた回数アンテナを回転させた所で、所定の閾値レベル以上の受信電力レベルが得られなかった場合には、最初のアンテナ位置から反対の方向へ所定の角度アンテナを回転させる。その後、所定の閾値以上の受信電力レベルが得られた最大のアンテナ位置でアンテナの回転制御を完了する。
【００４３】
なお、上記の方法では受信電力レベルが、所定の閾値レベル以上になった場合に、その間得られた受信電力レベルが最大のアンテナ位置でアンテナの回転制御を完了したが、過去の受信電力レベルの記録からその平均値を求め、その平均値から所定の割合以上の受信電力レベルが得られた場合に、そのアンテナ位置でアンテナの回転制御を完了してもよい。
【００４４】
上記２つの方法では、所定の回数アンテナを所定の角度回転させた後、所定の受信電力レベルが得られなかった場合には、最初のアンテナ位置から反対の方向へアンテナ位置を回転制御するようにしたが、あらかじめ定めた方向へアンテナ位置を回転させることで明らかに受信電力レベルが劣化したことが確認できた場合には、その時点で最初のアンテナ位置から反対の方向へアンテナを回転させるようアンテナを制御しても良い。
【００４５】
以上のようにアンテナを回転制御した結果、信号レベル検出手段１０８において受信電力レベルが所定の閾値以下である場合には、送信局１０のアンテナ回転制御を行う。
【００４６】
アンテナ制御手段１０９がアンテナ回転制御を行った結果、所定の閾値レベル以上の受信電力レベルが得られなかった場合、送信局１０の指向性アンテナ１０１を所定の方向へあらかじめ定めた角度回転させるための制御データを生成し、制御信号送信手段１１０へ出力する。制御信号送信手段１１０は制御データの変調処理を行い、制御信号を生成し、スイッチ手段１０２を介してアンテナ１０１から送信局１０に対して制御信号を送信する。
【００４７】
送信局１０は受信局２０が送信した制御信号を指向性アンテナ１０１で受信し、スイッチ手段１０２を介して信号受信手段１０４で制御信号の復調を行い、制御データを再生して、アンテナ制御手段１０５へ制御データを出力する。
【００４８】
アンテナ制御手段１０５は制御データを受信した後、その制御データの指示に従い、アンテナ駆動手段１０６に回転指示信号を送る。
【００４９】
アンテナ駆動手段１０６は軸を中心に指向性アンテナ１０１を回転させて指向方向を変化させる。
【００５０】
送信局１０側の指向性アンテナ１０１の向きが変わることにより、受信局２０への電波の到来方向が変わり、受信局２０の信号レベル検出手段１０８で検出する受信電力レベルが変化する。
【００５１】
送信局１０側へ制御信号を送信した後、受信局２０の信号レベル検出手段１０８で受信信号レベルを検出し、その値が所定の閾値レベル以上になった場合には、その位置で送信局のアンテナ制御を完了させるため、制御信号の送信を中止する。
【００５２】
しかし、所定の閾値レベル以上の受信電力レベルが得られない場合には、さらに送信局１０の指向性アンテナ１０１を所定の角度回転させるように制御信号を送信する。これを繰り返し、所定の閾値レベル以上の受信電力レベルが得られた時点で送信局１０へアンテナ制御用の制御信号の送信を中止する。
【００５３】
また、送信局へ制御データを送信するのは、受信局２０の指向性アンテナ１０１を制御する場合と同様の方法で、受信局２０の指向性アンテナ１０１を制御する代わりに、送信局１０の指向性アンテナ１０１を制御するために制御データを送信する。
【００５４】
以上のように、送信局１０及び受信局２０の指向性アンテナを制御することで、送信局１０あるいは受信局２０の近傍に障害物が存在し、電波障害が発生しても、送信局１０あるいは受信局２０いずれかあるいは双方の指向性アンテナを回転させることで所望の受信電力レベルが得られ、誤りの少ないデータ通信を行うことが可能となる。
【００５５】
（実施の形態２）
図２は、本発明の実施の形態２における送信局及び受信局の構成を示すブロック図である。図２において、図１と同じ構成要素については同じ符号を用い、説明を省略する。
【００５６】
図２において、１１２は送信局１０に対して受信電力レベル測定用にデータ信号を生成する信号生成手段である。
【００５７】
以上のように構成した送信局および受信局の動作について説明する。
【００５８】
受信局２０は送信局１０から送信された送信信号を指向性アンテナ１０１で受信すると、スイッチ手段１０２を介して信号受信手段１０７及び信号レベル検出手段１０８へ送られる。
【００５９】
信号受信手段１０７は、受信信号のプリアンブルの情報に従って復調するための無線周波数を補正し、受信信号を復調して元の受信データを再生する。
【００６０】
信号レベル検出手段１０８は、受信信号の電力を測定し、測定した受信信号レベルをアンテナ制御手段１０９に出力する。
【００６１】
アンテナ制御手段１０９は、信号受信手段１０７において受信信号の受信電力レベルが低すぎるために受信データの再生が不可能になる受信電力レベルの閾値を保持しておき、受信信号の受信電力レベルが所定の閾値以下になった場合にアンテナ駆動手段１０６にあらかじめ定めた方向に指向性アンテナ１０１を所定の角度回転させる回転指示信号を送る。
【００６２】
アンテナ駆動手段１０６は、軸を中心に指向性アンテナ１０１を回転させて指向方向を変化させる。
【００６３】
信号生成手段１１２は、送信局１０に対して受信電力レベル測定用にデータ信号を生成する信号生成手段であり、信号送信手段１０３に送信データが入力される。この送信データは、送信局１０が受信電力レベルを測定するためのデジタルデータである。信号送信手段１０３は送信データにデジタル変調を施し、受信局で送信データを正しく受信するために必要な情報をプリアンブルとしてデジタル変調を施した送信データフレームごとその先頭に付加し、無線伝送する周波数帯の送信信号に変換する。
【００６４】
信号送信手段１０３で生成された送信信号はスイッチ手段１０２から指向性アンテナ１０１へ送られ、送信局１０の指向性アンテナ１０１に送信される。
【００６５】
送信局１０は受信局２０から送信された送信信号を指向性アンテナ１０１で受信すると、スイッチ手段１０２を介して信号レベル検出手段１０８へ送られる。
【００６６】
信号レベル検出手段１０８は受信信号の電力を測定し、測定した受信信号レベルをアンテナ制御手段１０５に出力する。
【００６７】
アンテナ制御手段１０５は、受信信号の受信電力レベルが低すぎるために受信データの再生が不可能になる受信電力レベルの閾値を保持しておき、受信信号の受信電力レベルが所定の閾値以下になった場合にアンテナ駆動手段１０６にあらかじめ定めた方向に指向性アンテナ１０１を所定の角度回転させる回転指示信号を送る。
【００６８】
アンテナ駆動手段１０６は軸を中心に指向性アンテナ１０１を回転させて指向方向を変化させる。
【００６９】
このように請求項１とは異なり、送信局１０および受信局２０のそれぞれの指向性アンテナ１０１の駆動は、局独自で制御を行うことが可能となり、アンテナを回転させた場合の影響を瞬時に反映させることが可能となる。
【００７０】
（実施の形態３）
図３は、本発明の実施の形態３における送信局及び受信局の構成を示すブロック図である。図３において、図１と同じ構成要素については同じ符号を用い、説明を省略する。
【００７１】
図３において、１１３は受信局から受信した受信電力レベル値と受信局から送られてきた受信電力測定用信号により測定した送信局の受信電力レベルとを比較する信号レベル比較手段である。
【００７２】
１１４は、送信局１０に対して受信電力レベル測定用にデータ信号を生成するするとともに、信号レベル検出手段で検出した受信電力レベルを挿入して送信データを生成する信号生成手段であり、信号送信手段１０３に送信データが入力される。
【００７３】
以上のように構成した送信局および受信局の動作について説明する。
【００７４】
送信局１０は受信局２０から送信された送信信号を指向性アンテナ１０１で受信すると、スイッチ手段１０２を介して信号受信手段１０７及び信号レベル検出手段１０８へ送られる。
【００７５】
信号受信手段１０７は、受信した信号より受信局２０の受信電力レベル値を取り出し、信号レベル検出手段１０８は、受信信号の電力を測定し、それぞれ信号レベル比較手段１１３に出力する。
【００７６】
信号レベル比較手段１１３は、受信局の受信電力レベル値と測定した送信局の受信電力レベル値を比較し、比較結果をアンテナ制御手段１０５へ出力する。アンテナ制御手段１０５は、受信局２０の指向性アンテナ１０１を制御させる場合、信号送信手段１０３を介して制御信号を受信局へ送信し、送信側１０の指向性アンテナ１０１を制御させる場合は、アンテナ駆動手段１０６へあらかじめ定めた方向にアンテナを所定の角度回転させる回転指示信号を送る。
【００７７】
アンテナ駆動手段１０６は、軸を中心に指向性アンテナ１０１を回転させて指向方向を変化させる。
【００７８】
ここで送信局１０及び受信局２０の受信電力レベルの比較結果に基づき、アンテナを回転制御する方法として、送信局１０の近くに障害物がある場合に、受信局２０に向けて送信できる方向が限られ、受信側の受信電力レベルがより低下するため、受信局２０に比べて送信局１０の受信電力レベルが低い場合は受信局２０の指向性アンテナ１０１を回転制御させ、送信局に比べて受信局の受信電力レベルが低い場合は送信局１０の指向性アンテナ１０１を回線制御させる必要がある。
【００７９】
以上のように、障害物により近い側の指向性アンテナを回転制御させることにより、データ送信の誤りを抑えることが可能となる。
【００８０】
（実施の形態４）
図４は、本発明の実施の形態４における送信局及び受信局の構成を示すブロック図である。実施の形態１に示した受信局２０において信号誤り率算出手段１１１が新たに追加された。図４において、図１と同じ構成要素については同じ符号を用い、説明を省略する。
【００８１】
図４において、１１１は信号受信手段１０７にて復調した受信データにおいて受信データフレームごとの受信誤り率を算出し、どの程度受信誤りが発生しているかの算出を行う信号誤り率算出手段である。
【００８２】
以上のように構成した受信局の動作について説明する。
【００８３】
受信局２０は送信局１０から送信された送信信号を指向性アンテナ１０１で受信すると、スイッチ手段１０２を介して信号受信手段１０７へ送られる。信号受信手段１０７は、受信信号のプリアンブルの情報に従って復調するための無線周波数を補正し、受信信号を復調して元の受信データを再生する。
【００８４】
信号誤り率算出手段１１１は受信データフレームのフレーム誤り率の算出を行う。
【００８５】
なお、上記２つの方法について、複数フレームのフレーム誤り率を保持し、所定フレーム数ごとにそのフレーム誤り率を平均化してフレーム誤り率を求めてもよい。複数フレームの受信誤りを平均化することで瞬時的な受信電力の変動を抑えることができる。
【００８６】
信号誤り率算出手段１１１は上記の方法のいずれかにより算出した受信誤り率をアンテナ制御手段１０９に出力する。
【００８７】
アンテナ制御手段１０９は、信号受信手段１０７において受信信号のフレーム誤り率が高すぎるために受信データの再生が不可能になるフレーム誤り率の閾値を保持しておき、受信信号のフレーム誤り率が所定の閾値以上になった場合にアンテナ駆動手段１０６にあらかじめ定めた方向にアンテナを所定の角度回転させる回転指示信号を送る。
【００８８】
アンテナ駆動手段１０６は軸を中心に指向性アンテナ１０１を回転させて指向方向を変化させる。
【００８９】
上記受信誤り率に関して、良好なデータを受信できる一応の目安としては、ランダムなデジタルデータを伝送し、復調した際に、送信したデータのビット誤り率がＢＥＲ＝１０^−９以上必要となり、その際の信号のＳ／Ｎ比は約１６ｄＢ必要である。
【００９０】
このように、請求項１とは異なり、受信電力レベルの変動によるアンテナ制御ではなく、受信信号のフレーム誤り率の変動によるアンテナ制御を行うことにより、本来、受信電力レベルの強弱に比べて、より的確に受信データの誤りの発生を判断できるフレーム誤り率による判断の方が効果が大きいと考えられる。
【００９１】
【発明の効果】
以上のように、本発明のアンテナ制御方式によれば、宅内のような障害物が多く、人が歩き回ったりするような環境においても、常に最大の受信信号レベルが得られ、フレーム誤り率の低い最適な伝播環境が得られる。したがって、伝送誤りの少ない無線伝送ができ、映像などのストリームデータを途切れることなく無線伝送することが可能となる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態による送信局及び受信局の構成を示すブロック図
【図２】本発明の第２の実施の形態による送信局及び受信局の構成を示すブロック図
【図３】本発明の第３の実施の形態による送信局及び受信局の構成を示すブロック図
【図４】本発明の第４の実施の形態による送信局及び受信局の構成を示すブロック図
【図５】従来の基地局及び端末局の構成を示すブロック図
【符号の説明】
１０　送信局
２０　受信局
３０　基地局
４０　端末局
１０１　指向性アンテナ
１０２　スイッチ手段
１０３　信号送信手段
１０４　信号受信手段
１０５　アンテナ制御手段
１０６　アンテナ駆動手段
１０７　信号受信手段
１０８　信号レベル検出手段
１０９　アンテナ制御手段
１１０　制御信号送信手段
１１１　信号誤り率算出手段
１１２　信号生成手段
１１３　信号レベル比較手段
１１４　信号生成手段
３０１　指向性アンテナ
３０２　スイッチ手段
３０３　信号送信手段
３０４　信号受信手段
３０５　信号レベル検出手段
３０６　アンテナ制御手段
３０７　アンテナ駆動手段
４０１　無指向性アンテナ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention controls the rotation of an antenna so that a receiving station can obtain an optimal receiving state with few reception errors in a wireless communication system that performs stream data such as video or large-capacity data communication between a transmitting station and a receiving station. And an antenna control method for the same.
[0002]
[Prior art]
As a conventional antenna control method, a configuration in which rotation is controlled using a directional antenna as an antenna on the base station side and an omnidirectional antenna is used as an antenna on the terminal station side (for example, see Patent Document 1). .
[0003]
FIG. 5 is a block diagram showing a configuration of a conventional antenna control system.
[0004]
In FIG. 5, reference numeral 30 denotes a configuration of a base station, and reference numeral 40 denotes a configuration of a terminal station.
[0005]
The base station 30 has a directional antenna 301, a switch means 302 for separating a signal received by the directional antenna and a signal transmitted to the receiving station via the directional antenna 101, and 303, which modulates transmission data and sets a radio frequency. Signal transmission means for generating a transmission signal, signal reception means for demodulating a reception signal to generate reception data, signal level detection means for detecting a reception power level of the reception signal, and 306 according to the reception power level. An antenna control unit 307 for performing antenna control by using an antenna driving unit for rotating the directional antenna 301 is configured.
[0006]
The terminal station 40 includes a non-directional antenna 401, a signal transmitting unit 403 for modulating transmission data to generate a radio frequency transmission signal, and a signal receiving unit 404 for demodulating a reception signal to generate reception data. Is done.
[0007]
A method of performing data communication in the conventional base station 30 and terminal station 40 configured as described above will be described.
[0008]
The base station 30 modulates the transmission data into a radio frequency transmission signal by the signal transmission means 303 and transmits the modulated signal to the terminal station 40 via the directional antenna 301. The terminal station 40 receives the transmission signal of the base station 30 by the omnidirectional antenna 401, demodulates the signal by signal receiving means, and outputs the received data.
[0009]
Conversely, the terminal station 40 modulates the transmission data with the signal transmission means and transmits the data to the base station 30 via the omnidirectional antenna 401. When receiving the transmission signal of the terminal station 40 with the directional antenna 301, the base station 30 demodulates the signal with the signal receiving means and outputs the received data.
At the same time, the received power level of the received signal is detected by the signal level detecting means.
[0010]
The antenna control unit 306 controls the antenna driving unit 307 when the reception signal level decreases by a predetermined level, and prevents the reception signal level from decreasing by rotating the directional antenna 301.
[0011]
With this configuration, when the terminal station 40 moves and the reception power level detected by the signal level detection unit 305 of the base station 30 decreases, the reception signal level is prevented from decreasing by controlling the rotation of the directional antenna 301. can do.
[0012]
[Patent Document 1]
JP-A-09-321677
[0013]
[Problems to be solved by the invention]
However, in order to transmit large-capacity data such as video at high speed, it is necessary to use a millimeter wave band having a wide usable frequency band. For example, if a frequency band such as a 5 GHz band, a 25 GHz band, or a 60 GHz band is used, it is possible to communicate at a transmission speed of several tens of Mbits / sec or more, and stream data such as video data according to the DV (Digital Video) standard. And MPEG2 standards.
[0014]
However, in these frequency bands, the radio wave is highly straight, so that the transmission performance is greatly deteriorated in places where there are many obstacles such as a house. Also, due to the short wavelength, multipath fading, which occurs when the reflected wave reflected from a wall or the like overlaps the direct wave, occurs more frequently than when using a low frequency band, and the signal cannot be received normally. , A reception error occurs.
[0015]
In particular, by using an omnidirectional antenna, reflected waves from all directions will be received, and when a person walks around, the surrounding reflected waves will change, and multipath fading frequently occurs. Will occur.
[0016]
To avoid this, simply using a directional antenna on the terminal station side also degrades the reception power level of the signal when an obstacle is placed immediately in front of the terminal, resulting in a reception error. Occurs.
[0017]
[Means for Solving the Problems]
In order to solve the conventional problem, the antenna control method of the present invention includes a directional antenna at both a transmitting station and a receiving station, and rotates the directional antenna of the receiving station according to a received signal level detected at the receiving station. Control and place the antenna at the position where the maximum received power level is obtained, and when the predetermined received power level cannot be obtained, transmit an antenna control signal to the transmitting station and change the directional antenna of the transmitting station. The rotation is controlled from the receiving station side, and the directional antenna of the transmitting station is arranged at a position where the maximum received power level can be obtained.
[0018]
With this configuration, by controlling the rotation of the directional antennas of both the transmitting station and the receiving station, it is possible to arrange the directional antenna at the position where the reception power level is the maximum.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0020]
(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a transmitting station and a receiving station according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 10 denotes a transmitting station, and reference numeral 20 denotes a receiving station, which transmits images and data from the transmitting station to the receiving station.
[0021]
In the transmitting station 10, 101 is a directional antenna, 102 is switch means for separating a signal received by the directional antenna from a signal transmitted to the receiving station via the directional antenna 101, and 103 is a radio frequency modulator for modulating transmission data. A signal transmitting means for generating a transmission signal by converting the signal into a signal; 104, a signal receiving means for performing reception processing of the received signal separated by the switch means 102; 105, the antenna driving means 106 in accordance with a control signal received by the signal receiving means 104; The antenna control means 106 is an antenna driving means for rotating the directional antenna 101 under the control of the antenna control means 105.
[0022]
In the receiving station 20, the directional antenna 101, the switching means 102, and the antenna driving means 106 have the same configuration as the transmitting station 10. 107 is a signal receiving means for performing reception processing of the received signal separated by the switch means 102 and generating received data, 108 is a signal level detecting means for detecting the received power level of the received signal, and 109 is an antenna according to the received power level An antenna control unit that outputs an antenna control signal to the driving unit 106 and generates control data for controlling an antenna of the transmitting station. The antenna control unit 110 modulates the control data generated by the antenna control unit 109 to convert the control data into a radio frequency. It is a control signal transmitting means for generating a transmission signal.
[0023]
Operations of the transmitting station and the receiving station configured as described above will be described in detail.
[0024]
First, transmission data is input to the signal transmission means 103 of the transmission station 10. The transmission data is digital data obtained by compressing Internet data, video and audio into a stream format such as MPEG. The signal transmitting means 103 performs digital modulation on the transmission data, and adds the information necessary for correctly receiving the transmission data at the receiving station as a preamble to the head of each digitally modulated transmission data frame, and adds a frequency band for wireless transmission. To the transmission signal. Here, as the digital modulation method, phase modulation such as QPSK, quadrature amplitude modulation (QAM), or spread spectrum or orthogonal frequency division multiplexing (OFDM) is used in combination with these modulation methods. Further, the preamble includes information necessary for correcting a radio frequency, information on a modulation scheme, and the like.
[0025]
The transmission signal generated by the signal transmission unit 103 is transmitted from the switch unit 102 to the directional antenna 101 and transmitted to the directional antenna 101 of the receiving station 20. As the directional antenna 101, a directional antenna having directivity in the forward direction of the antenna surface is used. When an omnidirectional antenna such as a dipole antenna is used in an environment with many obstacles such as a house or in an environment where the radio wave fluctuates frequently due to the movement of people, the direction of arrival of the radio wave changes in a complicated manner and the received power level increases This is because it changes and it becomes difficult to perform the demodulation processing and the antenna control method in the signal receiving unit 107.
[0026]
When the receiving station 20 receives the transmission signal transmitted from the transmitting station 10 by the directional antenna 101, the transmission signal is sent to the signal receiving unit 107 and the signal level detecting unit 108 via the switching unit 102.
[0027]
The signal receiving means 107 corrects the radio frequency for demodulation according to the information of the preamble of the received signal, and demodulates the received signal to reproduce the original received data.
[0028]
Signal level detecting means 108 measures the power of the received signal. As a method of measuring the received power,
1) Calculate the average value of the power of the entire frame of the received signal in frame units
2) Find the power of the preamble of the received signal
There is a way.
[0029]
Further, the above two methods may hold the received power values of a plurality of frames, and average the received power values for each predetermined number of frames to obtain the received power. By averaging the power of a plurality of frames, it is possible to suppress instantaneous fluctuations in received power. In particular, when multi-level modulation is used, the amplitude after modulation is not uniform, so that the received power for each frame originally varies. Therefore, it is better to average the received power of a plurality of frames.
[0030]
The signal level detection means 108 outputs the reception signal level detected by any of the above methods to the antenna control means 109.
[0031]
The antenna control means 109 holds a threshold value of the reception power level at which the reception power level of the reception signal is too low in the signal reception means 107 to make it impossible to reproduce the reception data, and the reception power level of the reception signal becomes a predetermined value. When the value becomes equal to or less than the threshold value, a rotation instruction signal for rotating the directional antenna 101 by a predetermined angle in a predetermined direction is sent to the antenna driving means 106.
[0032]
The antenna driving means 106 changes the directional direction by rotating the directional antenna 101 about the axis.
[0033]
Next, there are several methods for controlling the rotation of the antenna, each of which will be described in detail.
[0034]
First, a first method for performing antenna rotation control will be described.
[0035]
The antenna control unit 109 rotates the directional antenna 101 by a predetermined angle in a predetermined direction and stops, and the signal level detection unit 108 detects the reception power level. As a result, when the reception power level becomes equal to or higher than the predetermined threshold level, the rotation control of the antenna is completed at the antenna position.
[0036]
However, if the reception power level equal to or higher than the predetermined threshold is not obtained, the antenna is further rotated by a predetermined angle. Complete.
[0037]
In addition, the number of rotations of the predetermined angle is determined in advance, and when the reception power level equal to or higher than the predetermined threshold level is not obtained at the point where the antenna is rotated the predetermined number of times, the opposite is performed from the first antenna position. Rotate the antenna at a predetermined angle in the direction. Thereafter, the rotation control of the antenna is completed at the antenna position where the reception power level equal to or higher than the predetermined threshold is obtained.
[0038]
In the above method, when the reception power level is equal to or higher than the predetermined threshold level, the rotation control of the antenna is completed.However, the average value is obtained from the record of the past reception power levels, and the predetermined value is obtained from the average value. When the received power level equal to or higher than the ratio is obtained, the rotation control of the antenna may be completed at the antenna position.
[0039]
Next, a second method for performing antenna rotation control will be described.
[0040]
The antenna control means 109 records the received signal level detected by the signal level detection means 108 and its antenna position while rotating the antenna by a predetermined angle in a predetermined direction, and rotates the antenna to a predetermined angle. When the maximum value of the received signal level obtained during the rotation of the antenna is equal to or greater than a predetermined threshold level, the antenna is rotated to the antenna position at which the maximum value is obtained, and the rotation of the antenna is controlled at the antenna position. Complete.
[0041]
However, if the received power level equal to or higher than the predetermined threshold is not obtained, the antenna is further rotated by a predetermined angle, and by repeating this, the antenna is rotated at the antenna position of the maximum received power level equal to or higher than the predetermined threshold level. Complete control.
[0042]
In addition, the number of rotations of the predetermined angle is determined in advance, and when the reception power level equal to or higher than the predetermined threshold level is not obtained at the point where the antenna is rotated the predetermined number of times, the opposite is performed from the first antenna position. Rotate the antenna at a predetermined angle in the direction. Then, the rotation control of the antenna is completed at the maximum antenna position where the reception power level equal to or higher than the predetermined threshold is obtained.
[0043]
In the above method, when the received power level becomes equal to or higher than a predetermined threshold level, the rotation control of the antenna is completed at the antenna position where the received power level obtained during that time is the maximum. The average value is obtained from the record, and when a received power level equal to or more than a predetermined ratio is obtained from the average value, the rotation control of the antenna at the antenna position may be completed.
[0044]
In the above two methods, after rotating the antenna a predetermined angle a predetermined number of times, if a predetermined reception power level is not obtained, the antenna position is controlled to rotate in the opposite direction from the initial antenna position. However, if it was confirmed that the received power level was clearly degraded by rotating the antenna position in the predetermined direction, the antenna was rotated from the initial antenna position in the opposite direction at that point. May be controlled.
[0045]
As a result of controlling the rotation of the antenna as described above, when the reception power level is equal to or less than the predetermined threshold value in the signal level detection unit 108, the antenna rotation of the transmitting station 10 is controlled.
[0046]
As a result of performing antenna rotation control by the antenna control means 109, if a reception power level equal to or higher than a predetermined threshold level is not obtained, the directional antenna 101 of the transmitting station 10 is rotated in a predetermined direction by a predetermined angle. It generates control data and outputs it to the control signal transmitting means 110. The control signal transmitting means 110 performs modulation processing of control data, generates a control signal, and transmits the control signal from the antenna 101 to the transmitting station 10 via the switch means 102.
[0047]
The transmitting station 10 receives the control signal transmitted by the receiving station 20 by the directional antenna 101, demodulates the control signal by the signal receiving means 104 via the switch means 102, reproduces the control data, and Outputs control data to
[0048]
After receiving the control data, the antenna control unit 105 sends a rotation instruction signal to the antenna driving unit 106 according to the instruction of the control data.
[0049]
The antenna driving means 106 changes the directional direction by rotating the directional antenna 101 about the axis.
[0050]
When the direction of the directional antenna 101 on the transmitting station 10 side changes, the direction of arrival of radio waves to the receiving station 20 changes, and the received power level detected by the signal level detecting means 108 of the receiving station 20 changes.
[0051]
After transmitting the control signal to the transmitting station 10, the received signal level is detected by the signal level detecting means 108 of the receiving station 20, and if the value is equal to or higher than a predetermined threshold level, the position of the transmitting station is detected at that position. The transmission of the control signal is stopped to complete the antenna control.
[0052]
However, when a reception power level equal to or higher than the predetermined threshold level cannot be obtained, a control signal is further transmitted to rotate the directional antenna 101 of the transmission station 10 by a predetermined angle. This is repeated, and transmission of the control signal for antenna control to the transmitting station 10 is stopped when the reception power level equal to or higher than the predetermined threshold level is obtained.
[0053]
The control data is transmitted to the transmitting station in the same manner as when the directional antenna 101 of the receiving station 20 is controlled, instead of controlling the directional antenna 101 of the receiving station 20. The control data is transmitted to control the antenna 101.
[0054]
As described above, by controlling the directional antennas of the transmitting station 10 and the receiving station 20, even if there is an obstacle near the transmitting station 10 or the receiving station 20 and radio interference occurs, the transmitting station 10 or the By rotating one or both of the directional antennas of the receiving station 20, a desired reception power level can be obtained, and data communication with few errors can be performed.
[0055]
(Embodiment 2)
FIG. 2 is a block diagram showing a configuration of a transmitting station and a receiving station according to Embodiment 2 of the present invention. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
[0056]
In FIG. 2, reference numeral 112 denotes a signal generation unit that generates a data signal for the transmission station 10 for measuring the reception power level.
[0057]
The operation of the transmitting station and the receiving station configured as described above will be described.
[0058]
When the receiving station 20 receives the transmission signal transmitted from the transmitting station 10 by the directional antenna 101, the transmission signal is sent to the signal receiving unit 107 and the signal level detecting unit 108 via the switching unit 102.
[0059]
The signal receiving means 107 corrects the radio frequency for demodulation according to the information of the preamble of the received signal, and demodulates the received signal to reproduce the original received data.
[0060]
The signal level detection means 108 measures the power of the received signal and outputs the measured received signal level to the antenna control means 109.
[0061]
The antenna control means 109 holds a threshold value of the reception power level at which the reception power level of the reception signal is too low in the signal reception means 107 to make it impossible to reproduce the reception data, and the reception power level of the reception signal becomes a predetermined value. When the value becomes equal to or less than the threshold value, a rotation instruction signal for rotating the directional antenna 101 by a predetermined angle in a predetermined direction is sent to the antenna driving means 106.
[0062]
The antenna driving means 106 changes the directional direction by rotating the directional antenna 101 about the axis.
[0063]
The signal generation unit 112 is a signal generation unit that generates a data signal for measuring the reception power level to the transmission station 10, and the transmission data is input to the signal transmission unit 103. This transmission data is digital data for the transmitting station 10 to measure the reception power level. The signal transmitting means 103 performs digital modulation on the transmission data, and adds the information necessary for correctly receiving the transmission data at the receiving station as a preamble to the head of each digitally modulated transmission data frame, and adds a frequency band for wireless transmission. To the transmission signal.
[0064]
The transmission signal generated by the signal transmission unit 103 is sent from the switch unit 102 to the directional antenna 101, and is transmitted to the directional antenna 101 of the transmission station 10.
[0065]
When the transmitting station 10 receives the transmission signal transmitted from the receiving station 20 by the directional antenna 101, the transmission signal is transmitted to the signal level detecting means 108 via the switching means 102.
[0066]
The signal level detecting means 108 measures the power of the received signal and outputs the measured received signal level to the antenna control means 105.
[0067]
The antenna control means 105 holds a threshold value of the reception power level at which the reception data cannot be reproduced because the reception power level of the reception signal is too low, and the reception power level of the reception signal becomes equal to or less than the predetermined threshold value. In this case, a rotation instruction signal for rotating the directional antenna 101 by a predetermined angle in a predetermined direction is sent to the antenna driving means 106.
[0068]
The antenna driving means 106 changes the directional direction by rotating the directional antenna 101 about the axis.
[0069]
Thus, different from the first aspect, the driving of the directional antennas 101 of the transmitting station 10 and the receiving station 20 can be controlled independently by the station, and the effect of rotating the antenna can be instantaneously determined. It can be reflected.
[0070]
(Embodiment 3)
FIG. 3 is a block diagram showing a configuration of a transmitting station and a receiving station according to Embodiment 3 of the present invention. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
[0071]
In FIG. 3, reference numeral 113 denotes signal level comparing means for comparing the received power level value received from the receiving station with the received power level of the transmitting station measured by the received power measuring signal transmitted from the receiving station.
[0072]
Reference numeral 114 denotes a signal generation unit that generates a data signal for the transmission station 10 for measuring the reception power level and inserts the reception power level detected by the signal level detection unit to generate transmission data. Transmission data is input to the means 103.
[0073]
The operation of the transmitting station and the receiving station configured as described above will be described.
[0074]
When the transmitting station 10 receives the transmission signal transmitted from the receiving station 20 by the directional antenna 101, the transmission signal is transmitted to the signal receiving means 107 and the signal level detecting means 108 via the switching means 102.
[0075]
The signal receiving unit 107 extracts the received power level value of the receiving station 20 from the received signal, and the signal level detecting unit 108 measures the power of the received signal and outputs the measured power to the signal level comparing unit 113, respectively.
[0076]
The signal level comparing means 113 compares the received power level value of the receiving station with the measured received power level value of the transmitting station, and outputs the comparison result to the antenna control means 105. When controlling the directional antenna 101 of the receiving station 20, the antenna control unit 105 transmits a control signal to the receiving station via the signal transmitting unit 103 and controls the directional antenna 101 of the transmitting side 10 by using an antenna. A rotation instruction signal for rotating the antenna by a predetermined angle in a predetermined direction is sent to the driving means 106.
[0077]
The antenna driving means 106 changes the directional direction by rotating the directional antenna 101 about the axis.
[0078]
Here, as a method of controlling the rotation of the antenna based on the comparison result of the reception power levels of the transmitting station 10 and the receiving station 20, when there is an obstacle near the transmitting station 10, the direction in which the signal can be transmitted toward the receiving station 20 is determined. If the reception power level of the transmitting station 10 is lower than that of the receiving station 20, the rotation of the directional antenna 101 of the receiving station 20 is controlled, and the reception power level of the receiving station 20 is lower than that of the transmitting station. When the reception power level of the receiving station is low, it is necessary to control the line of the directional antenna 101 of the transmitting station 10.
[0079]
As described above, by controlling the rotation of the directional antenna closer to the obstacle, it is possible to suppress an error in data transmission.
[0080]
(Embodiment 4)
FIG. 4 is a block diagram showing a configuration of a transmitting station and a receiving station according to Embodiment 4 of the present invention. Signal error rate calculating means 111 is newly added in receiving station 20 shown in the first embodiment. 4, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
[0081]
In FIG. 4, reference numeral 111 denotes a signal error rate calculation unit that calculates a reception error rate for each reception data frame in the reception data demodulated by the signal reception unit 107 and calculates how much reception error has occurred.
[0082]
The operation of the receiving station configured as described above will be described.
[0083]
When the receiving station 20 receives the transmission signal transmitted from the transmitting station 10 by the directional antenna 101, the transmission signal is transmitted to the signal receiving unit 107 via the switch unit 102. The signal receiving means 107 corrects the radio frequency for demodulation according to the information of the preamble of the received signal, and demodulates the received signal to reproduce the original received data.
[0084]
The signal error rate calculator 111 calculates a frame error rate of the received data frame.
[0085]
In the above two methods, the frame error rates may be obtained by holding the frame error rates of a plurality of frames and averaging the frame error rates for each predetermined number of frames. By averaging the reception errors of a plurality of frames, it is possible to suppress instantaneous fluctuations in the reception power.
[0086]
The signal error rate calculation means 111 outputs the reception error rate calculated by any of the above methods to the antenna control means 109.
[0087]
The antenna control means 109 holds a threshold value of a frame error rate at which the received data cannot be reproduced because the frame error rate of the received signal is too high in the signal receiving means 107, and the frame error rate of the received signal is set to a predetermined value. When the threshold value is exceeded, a rotation instruction signal for rotating the antenna in a predetermined direction by a predetermined angle is sent to the antenna driving means 106.
[0088]
The antenna driving means 106 changes the directional direction by rotating the directional antenna 101 about the axis.
[0089]
Regarding the above-mentioned reception error rate, as a rough guide to receive good data, when random digital data is transmitted and demodulated, the bit error rate of the transmitted data is BER = 10 ^-9 This is necessary, and the S / N ratio of the signal at that time needs to be about 16 dB.
[0090]
In this way, unlike the first aspect, by performing the antenna control not by the fluctuation of the reception power level but by the fluctuation of the frame error rate of the reception signal, the reception power level is originally higher than that of the reception power level. It is considered that the determination based on the frame error rate that can accurately determine the occurrence of an error in the received data is more effective.
[0091]
【The invention's effect】
As described above, according to the antenna control method of the present invention, the maximum reception signal level is always obtained even in an environment where there are many obstacles such as a house and people walk around, and the frame error rate is low. An optimal propagation environment is obtained. Therefore, wireless transmission with few transmission errors can be performed, and stream data such as video can be wirelessly transmitted without interruption.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a transmitting station and a receiving station according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a transmitting station and a receiving station according to a second embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration of a transmitting station and a receiving station according to a third embodiment of the present invention.
FIG. 4 is a block diagram showing a configuration of a transmitting station and a receiving station according to a fourth embodiment of the present invention.
FIG. 5 is a block diagram showing the configuration of a conventional base station and terminal station.
[Explanation of symbols]
10 transmitting station
20 receiving stations
30 base stations
40 terminal stations
101 Directional antenna
102 Switch means
103 signal transmission means
104 signal receiving means
105 Antenna control means
106 antenna driving means
107 signal receiving means
108 signal level detecting means
109 antenna control means
110 control signal transmitting means
111 signal error rate calculation means
112 signal generation means
113 signal level comparing means
114 signal generation means
301 Directional antenna
302 switch means
303 signal transmission means
304 signal receiving means
305 Signal level detecting means
306 Antenna control means
307 Antenna driving means
401 Omnidirectional antenna

Claims

In a wireless communication system that performs data communication between terminals using a wireless line,
The receiving station receives the data signal transmitted by the transmitting station via the directional antenna, detects the received power level of the received signal, and controls the rotation of the directional antenna according to the detected received power level, or Transmitting a control signal to the transmitting station,
An antenna control method in which a transmitting station performs rotation control of a directional antenna based on a control signal transmitted by a receiving station.

2. The reception station according to claim 1, wherein when the reception power level of the reception signal falls below a predetermined threshold, the reception station controls the rotation of the directional antenna or transmits a control signal to the transmission station. The antenna control method described in 1.

The receiving station according to claim 1, wherein after performing rotation control of the directional antenna, the receiving station transmits a control signal to the transmitting station when a reception power level cannot obtain a predetermined threshold. Antenna control method.

4. The antenna control method according to claim 1, wherein the transmitting station adds reception power level measurement data to a preamble of a transmission signal.

The receiving station performs rotation control of the directional antenna when the received power level of the received signal is lower than the value of the received power level received immediately before, or transmits a control signal to the transmitting station. The antenna control method according to claim 1.

The receiving station controls the rotation of the directional antenna when the received power level of the received signal is lower than a predetermined value width with respect to the value of the received power level received immediately before, or transmits a control signal to the transmitting station. The antenna control method according to claim 1, wherein

The receiving station controls the rotation of the directional antenna when the received power level of the received signal is lower than the average value of the received power levels received immediately before, or transmits a control signal to the transmitting station. The antenna control method according to claim 1, wherein:

The receiving station controls the rotation of the antenna when the average value of the received power levels received immediately before the received power level of the received signal is lower than a predetermined value width, or transmits a control signal to the transmitting station. The antenna control method according to claim 1, wherein:

The receiving station detects the level of the received power of the received signal, and after performing the rotation control of the directional antenna according to the detected received power level, transmits a data signal to the transmitting station,
The transmitting station receives the data signal transmitted by the receiving station via a directional antenna, detects a received power level of the received signal, and controls rotation of the directional antenna according to the detected received power level. Antenna control method to be used.

10. The antenna control method according to claim 9, wherein the transmitting station controls the rotation of the antenna when the received power level of the received signal falls below a predetermined threshold.

The antenna control method according to claim 9, wherein the receiving station periodically transmits a reception power level detection signal.

The antenna control method according to claim 9, wherein the receiving station adds reception power measurement data to a preamble of a transmission signal.

The receiving station transmits a reception power level detection signal and a reception power level value to the transmission station,
The transmitting station detects a reception power level by a reception power level detection signal transmitted from the reception station, and controls the directional antenna by comparing the reception power level with a reception power level value transmitted from the reception station. The antenna control method according to claim 9.

The transmitting station transmits a reception power level detection signal and a reception power level value to the reception station,
The receiving station detects the received power level by the received power level detection signal transmitted from the transmitting station, and controls the directional antenna by comparing the received power level with the received power level value transmitted from the transmitting station. The antenna control method according to claim 9.

In the receiving station or the transmitting station, calculate the reception error rate of the received signal, perform antenna control according to the calculated reception error rate, or transmit a control signal to the transmission station or the reception station, received The antenna control method according to any one of claims 1 to 9, wherein rotation control of the antenna is performed based on a control signal.

16. The antenna control method according to claim 1, wherein the antenna rotation control rotates an angle about a vertical axis.

The antenna rotation control rotates the angle every 90 degrees on the vertical axis, and between the position where the received power level is the highest and the position where the next received power level is the highest, the optimal antenna position while rotating the angle more finely. 17. The antenna control method according to claim 16, wherein

In a wireless communication system that performs data communication between a transmitting station and a receiving station using a wireless line,
The receiving station includes a directional antenna that receives a signal, a signal receiving unit that receives a signal via the directional antenna, a signal level detecting unit that detects a received power of the received signal, and an antenna driving unit that operates according to the received power level. Antenna controlling means for controlling the means, antenna driving means for rotating the directional antenna, and signal transmitting means for transmitting control data generated by the antenna controlling means to the transmitting station via the directional antenna, the transmitting station comprising: Directional antenna for receiving a signal, signal receiving means for receiving a signal via the directional antenna, antenna control means for controlling antenna driving means based on control data obtained by the receiving means, and directional antenna And an antenna driving means for rotating the antenna.

In a wireless communication system that performs data communication between a transmitting station and a receiving station using a wireless line,
Directional antenna for receiving a signal, signal receiving means for receiving a control signal transmitted from a receiving station via the directional antenna, and antenna control for controlling antenna driving means based on control data obtained by the receiving means And an antenna driving means for rotating the directional antenna.