JP3762332B2

JP3762332B2 - Wireless packet communication device

Info

Publication number: JP3762332B2
Application number: JP2002170853A
Authority: JP
Inventors: 保彦井上; 武男市川; 一賢斎藤; 正博守倉
Original assignee: Nippon Telegraph and Telephone Corp
Current assignee: Nippon Telegraph and Telephone Corp
Priority date: 2002-06-12
Filing date: 2002-06-12
Publication date: 2006-04-05
Anticipated expiration: 2022-06-12
Also published as: JP2004015783A

Description

【０００１】
【発明の属する技術分野】
本発明は、無線パケット通信装置に関し、特に、利用可能な複数の伝送速度の中から一の伝送速度を選択してデータの送信を行う無線パケット通信装置に関する。
【０００２】
【従来の技術】
無線パケット通信は、ＩＥＥＥ８０２．１１無線ＬＡＮをはじめとする様々なシステムで採用されている通信形態である。ＩＥＥＥ８０２．１１ａやＩＥＥＥ８０２．１１ｂ規格の物理層は、マルチレートをサポートする伝送速度制御手段を有してしており、この伝送速度制御手段は、送信するパケット毎に、利用可能な伝送速度（たとえば、ＩＥＥＥ８０２．１１ａ規格においては、利用可能な伝送速度として、６Ｍ、９Ｍ、１２Ｍ、１８Ｍ、２４Ｍ、３６Ｍ、４８Ｍ、５４Ｍｂｉｔ／ｓの８種類が規定されている。）の中から一の伝送速度を選択して使用する。
【０００３】
図５は、上記伝送速度制御手段を有する従来の無線パケット通信装置の例を示す図である。
送信器５１０に入力された送信データは、伝送速度制御手段５５０が指示する伝送速度で変調が行われ、送受切替器５３０を介してアンテナ５４０から送信される。
【０００４】
無線通信においては、一般に、より高速な伝送速度を使用する場合には、より高い通信品質が必要となる。
したがって、ある一つの通信品質が、ある伝送速度で安定的に通信を行うという観点からは良好であるが、その伝送速度の一つ上の伝送速度で通信を行うという観点からは劣悪であるという場合が存在する。
【０００５】
このため、前記伝送速度制御手段５５０は、通信品質の良悪に応じて伝送速度を制御すべく、内部に速度増加しきい値と速度低下しきい値を有し、送信器５１０から入力される送信データの送信通知と受信器５２０から入力される前記送信データに対する到達確認信号の受信通知とを比較することで、伝送路における通信品質を判定し（通信品質の判定には、たとえば、搬送波対雑音電力比（Ｓ／Ｎ：ＳｉｇｎａｌｔｏＮｏｉｓｅｒａｔｉｏ）を用いる。）、この判定した通信品質の良悪に基づいて伝送速度の制御を行う。
【０００６】
具体的には、伝送速度制御手段５５０は、前記送信通知に対応する前記到達確認信号の受信通知が前記送信通知の入力があってから一定時間以内に入力された場合に、データ送信が成功したものと判断する。
【０００７】
そして、前記伝送速度制御手段５５０は、無線パケットの送信が速度増加しきい値に規定される回数に渡り連続的に成功した場合には、通信品質が極めて良好であると判断し、使用する伝送速度を１段階増加するという制御を行う。
【０００８】
一方、前記伝送速度制御手段５５０は、無線パケットの送信が速度低下しきい値に規定される回数に渡り連続的に失敗した場合には、通信品質が極めて劣悪であると判断し、使用する伝送速度を一段低下させるという制御を行う。
【０００９】
なお、この場合、従来の無線パケット通信における前記伝送速度制御手段５５０の中には、通信品質が改善した場合でも、伝送速度を増加させるための条件を厳しくして、伝送速度の変更が頻繁に行われることを防止し、通信の安定化を行うものも存在する。
【００１０】
【発明が解決しようとする課題】
しかし、過去のデータ送信結果から通信品質を判定し、この判定した通信品質の良悪に基づいて伝送速度の決定を行うという従来の無線パケット通信装置、すなわち、ある伝送速度におけるデータの送信に基づき通信品質を判定し、この判定した通信品質の良悪に基づいて次の送信データの伝送速度を増加させるという従来の無線パケット通信装置では、通信品質が、当該伝送速度の増加後の伝送速度で通信を行うという観点からは劣悪である場合がある。
【００１１】
この場合、従来の無線パケット通信装置における送受信側は送信されたデータを正しく復調することができず、到達確認は受信側から送信側に返されない。
一方、従来の無線パケット通信装置における送信側は、送信データに対する到達確認がある一定の回数以上に渡り連続的に返らなかった場合でなければ伝送速度を以前の値に戻さない。
【００１２】
したがって、従来の無線パケット通信装置においては、伝送速度が以前の値に戻るまでのデータの送信が、すべて失敗することになる事態が生じ得る。
よって、従来の無線パケット通信装置においては、送受信間の通信リンクの観点からはスループットの低下が、また、無線ＬＡＮのようなシステム全体の観点からはシステム容量の減少が、深刻な問題となっていた。
【００１３】
そこで、本発明は、かかる事情に鑑み、スループットの向上およびシステム容量の増加を図ることができる無線パケット通信装置を提供することを目的とする。
【００１４】
【課題を解決するための手段】
本発明によれば、上記課題は、前記特許請求の範囲に記載の手段により解決される。
【００１５】
すなわち、請求項１に記載の発明は、送信信号の伝送速度を制御する伝送速度制御手段と、前記伝送速度制御手段の制御信号が指定する伝送速度に従って入力された送信データを変調し無線パケット信号を生成する送信器と、前記送信器の送信出力端子と受信器の受信入力端子を接続され、送信時には前記送信出力端子を共通端子に接続し、受信時には前記受信入力端子を共通端子に接続する送受切替器と、前記送受切替器の受信入力端子に接続され、受信した無線パケット信号を復調して受信データを出力する受信器と、アンテナと、正しく受信したデータに対する到達確認信号の返送を含む通信手順の処理を行う無線プロトコル処理手段と、を備え、
前記伝送速度制御手段が、送信器より入力された送信通知と受信器より入力された前記到達確認信号の受信通知との比較を行うことにより、通信品質を判定し、当該判定の結果に基づき、次に送信する無線パケット信号を生成する際の伝送速度を決定する、無線パケット通信装置において、
前記伝送速度制御手段は、
速度増加しきい値Ｕ、速度低下しきい値Ｄ、速度定着しきい値Ｆの３つの定数ならびにタイマーを有し、かつ、通常状態、速度増加監視状態、速度低下監視状態のうちのいずれかの状態にあり、
前記通常状態の場合であって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知とを比較した結果、無線パケット信号の送信成功が前記速度増加しきい値Ｕに規定される回数以上連続的に観測された場合（以下、「（ａ−１）の場合」という。）には、
通信品質が極めて良好であると判断し、使用中の伝送速度よりも高い速度が利用可能であれば、使用する伝送速度を一段階高い速度に変更するとともに前記タイマーを始動し速度増加監視状態への遷移を行い、一方、使用中の伝送速度が利用可能な最高の伝送速度であれば現在の状態を維持し、
前記通常状態の場合であって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知とを比較した結果、無線パケット信号の送信失敗が前記速度低下しきい値Ｄに規定される回数以上連続的に観測された場合（以下、「（ａ−２）の場合」という。）には、
通信品質が劣化したと判断し、使用中の伝送速度よりも低い速度が利用可能であれば、使用する伝送速度を一段階低い伝送速度に変更するとともに前記タイマーを始動し速度低下監視状態への遷移を行い、一方、使用中の伝送速度が利用可能な最低の伝送速度であれば現在の状態を維持し、
前記通常状態の場合であって、かつ、上記（ａ−１）の場合および（ａ−２）の場合以外の場合には、通常状態を維持し、
また、前記速度増加監視状態にあって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知とを比較した結果、無線パケット信号の連続的な送信成功が前記速度定着しきい値Ｆに規定される回数に満たなかった場合（以下「（ｂ−１）の場合」という。）には、
使用する伝送速度を一段階低い伝送速度に変更するとともに前記タイマーを停止し通常状態への遷移を行い、
前記速度増加監視状態にあって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知とを比較した結果、無線パケット信号の送信成功が前記速度増加しきい値Ｕに規定される回数以上連続的に観測された場合（以下、「（ｂ−２）の場合」という。）には、
通信品質が極めて良好であると判断し、使用中の伝送速度よりも高い速度が利用可能であれば、使用する伝送速度を一段階高い速度に変更して現在の状態を維持し、一方、使用中の伝送速度が利用可能な最高の伝送速度であれば、前記タイマーを停止し通常状態への遷移を行い、
前記速度増加監視状態にあって、かつ、前記タイマーのタイムアウトにより、本状態への遷移後の経過時間が規定値Ｔ１を越えたことを確認した場合（以下、「（ｂ−３）の場合」という。）には、通常状態への遷移を行い、
前記速度増加監視状態にあって、かつ、前記（ｂ−１）の場合および（ｂ−２）の場合および（ｂ−３）の場合以外の場合には、速度増加監視状態を維持し、
さらに、前記速度低下監視状態であって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知とを比較した結果、無線パケット信号の送信失敗が前記速度低下しきい値Ｄに規定される回数以上連続的に観測された場合（以下、「（ｃ−１）の場合」という。）には、
通信品質が劣化したと判断し、使用中の伝送速度よりも低い速度が利用可能であれば、使用する伝送速度を一段階低い速度に変更して現在の状態を維持し、一方、使用中の伝送速度が利用可能な最低の伝送速度であれば、前記タイマーを停止し通常状態への遷移を行い、
前記速度低下監視状態であって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知とを比較した結果、無線パケット信号の送信成功が前記速度増加しきい値Ｕに規定される回数以上連続的に観測された場合（以下、「（ｃ−２）の場合」という。）には、
通信品質が極めて良好であると判断し、前記タイマーを停止し通常状態への遷移をおこない、
前記速度低下監視状態であって、かつ、前記タイマーのタイムアウトにより、本状態への遷移後の経過時間が規定値Ｔ２を越えたことを確認した場合（以下、「（ｃ−３）の場合」という。）には、通常状態への遷移を行い、
前記速度低下監視状態であって、かつ、前記（ｃ−１）の場合および（ｃ−２）の場合および（ｃ−３）の場合以外の場合には、速度低下監視状態を維持する、ことを特徴とする無線パケット通信装置である。
【００１６】
請求項１に記載の発明によれば、伝送速度制御手段は、従来とは異なり、伝送速度定着しきい値を有し、通信品質が良好であると判断して伝送速度を増加させた後、安定的に通信が行えなかった場合に、直ちに直前の伝送速度に戻す制御を行う。
【００１７】
請求項２に記載の発明は、前記伝送速度制御手段は、速度増加しきい値Ｕｉ（ｉ＝１、２、・・・、ｎ）、速度低下しきい値Ｄｉ（ｉ＝１、２、・・・、ｎ）、速度定着しきい値Ｆｉ（ｉ＝１、２、・・・、ｎ）、
ならびに、使用する速度増加しきい値Ｕｉ（ｉ＝１、２、・・・、ｎ）と伝送速度との対応、使用する速度低下しきい値Ｄｉ（ｉ＝１、２、・・・、ｎ）と伝送速度との対応、使用する速度定着しきい値Ｆｉ（ｉ＝１、２、・・・、ｎ）と伝送速度との対応、
を管理し、
現在使用している伝送速度に応じて前記速度増加しきい値、速度低下しきい値、速度定着しきい値の値を動的に変更することを特徴とする請求項１に記載の無線パケット通信装置である。
【００１８】
請求項２に記載の発明によれば、伝送速度制御手段は、従来とは異なり、複数の速度増加しきい値、速度低下しきい値、および速度定着しきい値を有し、使用している伝送速度に応じて、速度増加しきい値、速度低下しきい値、および速度定着しきい値の値を使い分ける。
【００１９】
請求項３に記載の発明は、送信信号の伝送速度と送信するアンテナの選択とを制御する伝送速度及びアンテナ切替制御手段と、前記伝送速度及びアンテナ切替制御手段の制御信号が指定する伝送速度に従って入力された送信データを変調し無線パケット信号を生成する送信器と、前記送信器の送信出力端子と受信器の受信入力端子を接続され、送信時には前記送信出力端子を共通端子に接続し、受信時には前記受信入力端子を共通端子に接続する送受切替器と、複数のアンテナを接続され、前記伝送速度及びアンテナ切替制御手段から入力された制御信号に従って複数のアンテナの中から一のアンテナを選択して前記送受切替器の共通端子と接続するアンテナ切替器と、前記送受切替器の受信入力端子に接続され、受信した無線パケット信号を復調して受信データを出力する受信器と、正しく受信したデータに対する到達確認信号の返送を含む通信手順の処理を行う無線プロトコル処理手段と、を備え、
前記伝送速度制御手段が、送信器より入力された送信通知と受信器より入力された前記到達確認信号の受信通知との比較を行うことにより、通信品質を判定し、当該判定の結果に基づき、次に送信する無線パケット信号を生成する際の伝送速度を決定する無線パケット通信装置において、
前記伝送速度制御手段は、速度増加しきい値Ｕ、速度低下しきい値Ｄ、速度定着しきい値Ｆの３つの定数ならびにタイマーを有し、かつ、通常状態、アンテナ切替監視状態、速度増加監視状態、速度低下監視状態のうちのいずれかの状態にあり、
前記通常状態であって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知とを比較した結果、無線パケット信号の送信成功が前記速度増加しきい値Ｕに規定される回数以上連続的に観測された場合（以下、「（ａ２−１）の場合」という。）には、
通信品質が極めて良好であると判断し、使用中の伝送速度よりも高い速度が利用可能であれば、使用する伝送速度を一段階高い速度に変更するとともに、前記タイマーを始動し速度増加監視状態への遷移を行い、一方、使用中の伝送速度が利用可能な最高の伝送速度であれば、通常状態を維持し、
前記通常状態であって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知とを比較した結果、無線パケット信号の送信失敗が前記速度低下しきい値Ｄに規定される回数以上連続的に観測された場合（以下、「（ａ２−２）の場合」という。）には、
通信品質が劣化したと判断し、使用中の伝送速度よりも低い速度が利用可能であれば、使用する伝送速度を一段階低い伝送速度に変更するとともに前記タイマーを始動し速度低下監視状態への遷移を行い、一方、使用中の伝送速度が利用可能な最低の伝送速度であれば、現在の状態を維持し、
前記通常状態であって、かつ、前記（ａ２−１）の場合および（ａ２−２）の場合以外の場合には、通常状態を維持し、
前記速度増加監視状態であって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知とを比較した結果、無線パケット信号の連続的な送信成功が前記速度定着しきい値Ｆに規定される回数に満たなかった場合（以下、「（ｂ２−１）の場合」という。）には、
使用する伝送速度を一段階低い伝送速度に変更するとともに前記タイマーを停止し通常状態への遷移を行い、
前記速度増加監視状態であって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知と比較した結果、無線パケット信号の送信成功が前記速度増加しきい値Ｕに規定される回数以上連続的に観測された場合（以下、「（ｂ２−２）の場合」という。）には、
通信品質が極めて良好であると判断し、使用中の伝送速度よりも高い速度が利用可能であれば、使用する伝送速度を一段階高い速度に変更して現在の状態を維持し、一方、使用中の伝送速度が利用可能な最高の伝送速度であれば、前記タイマーを停止し通常状態への遷移を行い、
前記速度増加監視状態であって、かつ、前記タイマーのタイムアウトにより、本状態への遷移後の経過時間が規定値Ｔｌを越えたことを確認した場合（以下、「（ｂ２−３）の場合」という。）には、通常状態への遷移を行い、
前記速度増加監視状態であって、かつ、前記（ｂ２−１）の場合および（ｂ２−２）の場合および（ｂ２−３）の場合以外の場合には、速度増加監視状態を維持し、
前記アンテナ切替監視状態であって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知とを比較した結果、無線パケット信号の送信成功が前記速度増加しきい値Ｕに規定される回数以上連続的に観測された場合（以下、「（ｃ２−１）の場合」という。）には、
通信品質が極めて良好であると判断し、前記タイマーを停止し通常状態への遷移をおこない、
前記アンテナ切替監視状態であって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知とを比較した結果、無線パケット信号の送信失敗が前記速度低下しきい値Ｄに規定される回数以上連続的に観測された場合（以下、「（ｃ２−２）の場合」という。）には、
通信品質が劣化したと判断し、これまで使用していたアンテナとは異なるアンテナへの切替を実行するとともに、使用中の伝送速度よりも低い伝送速度が使用可能であれば、使用する伝送速度を一段階低い伝送速度に変更し、前記タイマーを再始動して速度低下監視状態への遷移を行い、一方、使用中の伝送速度が最低速度であれば、前記タイマーを停止し通常状態への状態遷移を行い、
前記アンテナ切替監視状態であって、かつ、前記タイマーのタイムアウトにより、本状態への遷移後の経過時間が規定値Ｔ３を越えたことを確認した場合（以下、「（ｃ２−３）の場合」という。）には、通常状態への状態遷移を行い、
前記アンテナ切替監視状態であって、かつ、前記（ｃ２−１）の場合および（ｃ２−２）の場合および（ｃ２−３）の場合以外の場合には、アンテナ切替監視状態を維持し、
前記速度低下監視状態であって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知とを比較した結果、無線パケット信号の送信失敗が前記速度低下しきい値Ｄに規定される回数以上連続的に観測された場合（以下、「（ｄ２−１）の場合」という。）には、
通信品質が劣化したと判断し、現在使用している伝送速度よりも低い速度が利用可能であれば、使用する伝送速度を一段階低い速度に変更して現在の状態を維持し、一方、現在使用している伝送速度が利用可能な最低の伝送速度であれば、前記タイマーを停止し通常状態への遷移を行い、
前記速度低下監視状態であって、かつ、前記送信器より入力された送信通知と前記受信器より入力された到達確認信号の受信通知とを比較した結果、無線パケット信号の送信成功が前記速度増加しきい値Ｕに規定される回数以上連続的に観測された場合（以下、「（ｄ２−２）の場合」という。）には、
通信品質が極めて良好であると判断し、前記タイマーを停止し通常状態への遷移をおこない、
前記速度低下監視状態であって、かつ、前記タイマーのタイムアウトにより、本状態への遷移後の経過時間が規定値Ｔ２を越えたことを確認した場合（以下、「（ｄ２−３）の場合」という。）には、通常状態への遷移を行い、
前記速度低下監視状態であって、かつ、前記（ｄ２−１）の場合および（ｄ２−２）の場合および（ｄ２−３）の場合以外の場合には、速度低下監視状態を維持する、ことを特徴とする無線パケット通信装置である。
【００２０】
請求項３に記載の発明によれば、伝送速度及びアンテナ切替制御手段は、従来とは異なり、伝送速度定着しきい値を有し、通信品質が良好であると判断して伝送速度を増加させた後、安定的に通信が行えなかった場合に、直ちに直前の伝送速度に戻す制御を行う。
【００２１】
請求項４に記載の発明は、前記伝送速度及びアンテナ切替制御手段は、
速度増加しきい値Ｕｉ（ｉ＝１、２、・・・、ｎ）、速度低下しきい値Ｄｉ（ｉ＝１、２、・・・、ｎ）、速度定着しきい値Ｆｉ（ｉ＝１、２、・・・、ｎ）、
ならびに、使用する速度増加しきい値Ｕｉ（ｉ＝１、２、・・・、ｎ）と伝送速度との対応、使用する速度低下しきい値Ｄｉ（ｉ＝１、２、・・・、ｎ）と伝送速度との対応、使用する速度定着しきい値Ｆｉ（ｉ＝１、２、・・・、ｎ）と伝送速度との対応、
を管理し、
現在使用している伝送速度に応じて前記速度増加しきい値、速度低下しきい値、速度定着しきい値の値を動的に変更することを特徴とする請求項３に記載の無線パケット通信装置である。
【００２２】
請求項４に記載の発明によれば、伝送速度及びアンテナ切替制御手段は、従来とは異なり、複数の速度増加しきい値、速度低下しきい値、および速度定着しきい値を有し、通信品質の判定を行う際に、使用している伝送速度に応じて、速度増加しきい値、速度低下しきい値、および速度定着しきい値の値を使い分ける。
【００２３】
【発明の実施の形態】
＜請求項１に記載の発明および請求項２に記載の発明の実施の形態＞
図１は、請求項１に記載の発明および請求項２に記載の発明に係る無線パケット通信装置の構成例を示す図である。
【００２４】
送信データは、無線プロトコル処理手段１００を介して送信器１１０に入力され、無線周波数へ変調される。このとき、送信器１１０は、伝送速度制御手段１５０により指示された速度で変調を行い、送信終了後には送信通知を前記伝送速度制御手段１５０に出力する。
【００２５】
送信器１１０で生成した無線パケット信号は、送受切替器１３０に入力される。この送受切替器１３０は、無線パケット信号の送信時には、入力された無線パケット信号をアンテナ１４０が接続される共通端子に出力する。
【００２６】
一方、送受切替器１３０は、無線パケット信号の受信時には、共通端子に接続されたアンテナ１４０からの受信信号を、受信器１２０に入力する。受信器１２０は、入力された無線パケット信号を正しく復調できた場合には、データを無線プロトコル処理手投１００へ出力する。
【００２７】
無線プロトコル処理手段１００は、受信器１２０の出力信号を入力された場合には、到達確認信号を、送信器１１０、送受信切替器１３０、アンテナ１４０を介して、データを送信した無線パケット通信装置に対して送信する。
【００２８】
データを送信した無線パケット通信装置の受信器１２０は、送信したデータに対する到達確認信号をアンテナ１４０を介して受信した場合、この受信通知を伝送速度制御手段１５０に入力する。
【００２９】
伝送速度制御手段１５０は、送信通知に対応する受信通知が返された場合にはデータの送信に成功したとみなし、送信通知に対応する受信通知が規定時間以内に返されない場合には送信が失敗したとみなす。
【００３０】
請求項１に記載の発明に係る無線パケット通信装置の構成例においては、伝送速度制御手投１５０は、内部に速度増加しきい値Ｕ、速度低下しきい値Ｄ、速度定着しきい値Ｆを有し、これらのしきい値と過去のデータ送信結果の履歴から、送受信装置間の通信品質の判定を行う。
【００３１】
ここで、通信品質の判定は、次のように行われる。すなわち、伝送速度制御手段１５０は、送信データに対応する到達確認信号が、速度増加しきい値Ｕに規定される回数に渡り連続的に受信された場合には、通信品質が極めて良好であると判定する。
【００３２】
また、送信データに対応する到達確認信号が、一定時間以内に、速度低下しきい値Ｄに規定される回数に渡り連続的に受信されなかった場合には、通信品質が悪いと判定する。
【００３３】
さらに、伝送速度制御手段１５０は、伝送速度を増加させた後、データの送信が、速度定着しきい値Ｆに規定される回数に渡り連続的に失敗した場合には、通信品質が不十分であると判定する。そして、伝送速度制御手段１５０は、上述の通信品質の判定にもとづき、使用する伝送速度の決定を行う。
伝送速度の決定は、図３に記載の方法により、行われる。
【００３４】
図３は、伝送速度制御手段１５０による、使用する伝送速度の決定方法を示す図である。
同図において、条件Ａは通信品質が極めて良好であると判定されたされた場合、条件Ｂは通信品質が悪いと判定された場合、条件Ｃは通信品質が不十分であると判定された場合を意味する。
【００３５】
伝送速度制御手段１５０は、通常状態、速度増加監視状態、速度低下監視状態の３つの状態のいずれかにあり、下記の条件にしたがって状態遷移を行いながら、伝送速度の制御を行う。
【００３６】
［通常状態］
まず、伝送速度制御手段１５０は、通常状態にある場合、次の処理を行う。
伝送速度制御手段１５０は、通信品質が極めて良好であると判定された場合（条件Ａが成立した場合）には、現在使用している伝送速度に応じて次の処理を行う。すなわち、使用中の伝送速度よりもさらに高い速度が利用可能な場合には、使用する伝送速度を一段階増加させるとともに、速度増加監視状態への状態遷移を行う。
【００３７】
また、伝送速度制御手段１５０は、速度増加監視状態へ遷移してからの経過時間を計測するために、タイマーを始動する。
伝送速度制御手段１５０は、使用中の伝送速度よりも高い速度が利用できない場合、すなわち、現在使用している伝送速度が最高速度であった場合には、現在の状態にとどまる。
【００３８】
一方、伝送速度制御手段１５０は、通信品質が悪いと判定された場合（条件Ｂが成立した場合）には、使用中の伝送速度に応じて次の処理を行う。すなわち、使用中の伝送速度よりもさらに低い速度が利用可能な場合には、使用する伝送速度を一段階低下させるとともに速度低下監視状態への状態遷移を行う。
【００３９】
また、伝送速度制御手段１５０は、速度低下監視状態へ遷移してからの経過時間を計測するために、タイマーを始動する。
伝送速度制御手段１５０は、使用中の伝送速度よりも低い速度が利用できない場合、すなわち、現在使用している伝送速度が最低速度であった場合には、現在の状態を維持する。
【００４０】
［速度増加監視状態］
また、伝送速度制御手段１５０は、速度増加監視状態にある場合には、次の処理を行う。
【００４１】
伝送速度制御手段１５０は、通信品質が不十分であると判定された場合（条件Ｃが成立した場合）には、現在の状態に遷移する際に始動したタイマーを停止し、使用する伝送速度を一段階低下させるとともに、通常状態への状態遷移を行う。
【００４２】
伝送速度制御手段１５０は、通信品質が極めて良好であると判定された場合（条件Ａが成立した場合）には、使用中の伝送速度に応じて次の処理を行う。
すなわち、使用中の伝送速度よりもさらに高い速度が利用可能な場合には、使用する伝送速度を一段階増加させ、速度増加監視状態を維持する。
【００４３】
一方、伝送速度制御手段１５０は、使用中の伝送速度よりも高い速度が利用できない場合、すなわち、使用中の伝送速度が最高速度であった場合には、タイマーを停止し、通常状態への状態遷移を行う。
【００４４】
また、伝送速度制御手段１５０は、速度増加監視状態に遷移する際に始動したタイマーがタイムアウトし、現在の状態へ遷移してからの経過時間が規定値Ｔ１を超えたことを検出した場合には、通常状態への状態遷移を行う。
【００４５】
［速度低下監視状態］
伝送速度制御手段１５０は、速度低下監視状態にある場合には、次の処理を行う。
伝送速度制御手段１５０は、通信品質が悪いと判定された場合（条件Ｂが成立した場合）には、使用中の伝送速度に応じて次の処理を行う。すなわち、使用中の伝送速度よりもさらに低い速度が利用可能な場合には、使用する伝送速度を一段階低下させ、速度低下監視状態を維持する。
【００４６】
伝送速度制御手段１５０は、使用中の伝送速度よりも低い速度が利用できない場合、すなわち、使用中の伝送速度が最低速度であった場合には、タイマーを停止し、通常状態への状態遷移を行う。
【００４７】
一方、伝送速度制御手段１５０は、通信品質が極めて良好であると判定された場合（条件Ａが成立した場合）には、タイマーを停止し、通常状態への状態遷移を行う。
【００４８】
また、伝送速度制御手段１５０は、タイマーのタイムアウトにより、速度低下監視状態へ遷移してからの経過時間が規定値Ｔ２を超えたことを検出した場合には、通常状態への状態遷移を行う。
【００４９】
請求項２に記載の発明に係る無線パケット通信装置の構成例においては、伝送速度制御手段１５０が、内部に複数の速度増加しきい値Ｕｉ（ｉ＝１、２、・・・、ｎ）、速度低下しきい値Ｄｉ（ｉ＝１、２、・・・、ｎ）、速度定着しきい値Ｆｉ（ｉ＝１、２、・・・、ｎ）を有し、伝送速度に応じた通信品質の判定の際に使用するしきい値の値を動的に変化させ、上記制御を行う。
例えば、伝送速度制御手段１５０は、伝送速度Ｒ３を使用している場合には、通信品質の判定において速度増加しきい値Ｕ３、速度低下しきい値Ｄ３、速度定着しきい値Ｆ３を使用する。
【００５０】
無線パケットを送信する際には、使用する伝送速度に応じて伝送効率が異なる場合が多い。このため、速度増加しきい値、速度低下しきい値、および速度定着しきい値をそれぞれある値に固定した場合、使用中の伝送速度によっては伝送効率の低下が問題となるが、請求項２に記載の発明に係る無線パケット通信装置の構成例における伝送速度制御手段１５０によれば、効率の低下を抑制しつつ伝送速度の制御を行うことができる。
【００５１】
＜請求項３に記載の発明ならびに請求項４に記載の発明の実施の形態＞
図２は、請求項３に記載の発明ならびに請求項４に記載の発明に係る無線パケット通信装置の構成例を示す図である。
【００５２】
送信データは、無線プロトコル処理手段１００を介して送信器１１０に入力され、無線周波数へ変調される。このとき、送信器１１０は、伝送速度及びアンテナ切替制御手段１６０により指示された速度で変調を行い、送信終了後には送信通知を前記伝送速度及びアンテナ切替制御手段１６０に出力する。
【００５３】
送信器１１０で生成された無線パケット信号は、送受切替器１３０に入力される。送受切替器１３０は、無線パケット信号の送信時には、入力された無線パケット信号をアンテナ切替器１７０が接続される共通端子に出力する。
【００５４】
アンテナ切替器１７０は、伝送速度及びアンテナ切替制御手段１６０から入力される制御信号に基づき、接続された複数のアンテナ１４０ａ、１４０ｂの中から一のアンテナを選択し無線パケット信号を送信する。
【００５５】
一方、送受切替器１３０は、無線パケット信号の受信時には、共通端子に接続されたアンテナ切替器１７０からの受信信号を、受信器１２０に入力する。
受信器１２０は、入力された無線パケット信号を正しく復調できた場合には、復調したデータを、無線プロトコル処理手段１００へ出力する。
【００５６】
無線プロトコル処理手段１００は、この復調されたデータを入力された場合には、送信器１１０、送受切替器１３０、アンテナ切替器１７０、アンテナ１４０ａまたはアンテナ１４０ｂを介して、データを送信した無線パケット通信装置に対して、到達確認信号を送信する。
【００５７】
また、データを送信した無線パケット通信装置における受信器１２０は、送信したデータに対する到達確認信号を、アンテナ１４０ａまたはアンテナ１４０ｂ、アンテナ切替器１７０、送受切替器１３０を介して受信した場合、この受信通知を伝送速度制御手段１５０に与える。
【００５８】
伝送速度制御手段１５０は、送信通知に対応する受信通知が返された場合にはデータの送信が成功したとみなし、送信通知に対応する受信通知が規定時間以内に返されない場合には送信が失敗したとみなす。
【００５９】
請求項２に記載の発明に係る無線パケット通信装置の構成例においては、伝送速度及びアンテナ切替制御手段１６０は、内部に速度増加しきい値Ｕ、速度低下しきい値Ｄ、速度定着しきい値Ｆを有し、これらのしきい値と過去のデータ送信結果の履歴から、送受信装置間の通信品質の判定を行う。
【００６０】
ここで、通信品質の判定は、次のように行われる。
伝送速度及びアンテナ切替制御手段１６０は、送信データに対応する到達確認信号を、速度増加しきい値Ｕにより規定される回数に渡り連続的に受信した場合には、通信品質が極めて良好であると判定する。
【００６１】
また、伝送速度及びアンテナ切替制御手段１６０は、送信データに対応する到達確認信号が、一定時間以内に、速度低下しきい値Ｄにより規定される回数に渡り連続的に受信されない場合には、通信品質が悪いと判定する。
さらに、伝送速度及びアンテナ切替制御手段１６０は、伝送速度を増加させた後、データの送信が、速度定着しきい値Ｆにより規定される回数に渡り連続的に失敗した場合には、通信品質が不十分であると判定する。
【００６２】
伝送速度及びアンテナ切替制御手段１６０は、上述の通信品質の判定にもとづき、使用する伝送速度および使用するアンテナの決定を行う。
この使用する伝送速度および使用するアンテナの決定は、図４に記載の方法により行われる。
【００６３】
図４は、伝送速度及びアンテナ切替制御手段１６０による、使用する伝送速度および使用するアンテナの決定方法を示す図である。
同図において、条件Ａは通信品質が極めて良好であると判定されたされた場合、条件Ｂは通信品質が悪いと判定された場合、条件Ｃとは通信品質が不十分であると判定された場合を意味する。
【００６４】
伝送速度及びアンテナ切替制御手段１６０は、通常状態、速度増加監視状態、アンテナ切替監視状態、速度低下監視状態の４つの状態のいずれかにあり、下記の条件にしたがって状態遷移を行いながら、伝送速度及びアンテナ切替の制御を行う。
【００６５】
［通常状態］
伝送速度及びアンテナ切替制御手段１６０は、通常状態にある場合には次の処理を行う。
【００６６】
伝送速度及びアンテナ切替制御手段１６０は、通信品質が極めて良好であると判定された場合（条件Ａが成立した場合）には、使用中の伝送速度に応じて次の処理を行う。すなわち、使用中の伝送速度よりもさらに高い速度が利用可能な場合には、これまで使用していたアンテナの使用を継続しつつ、使用する伝送速度を一段階増加させるとともに、速度増加監視状態への状態遷移を行う。
【００６７】
伝送速度及びアンテナ切替制御手段１６０は、このとき、速度増加監視状態へ遷移してからの経過時間を計測するために、タイマーを始動する。
伝送速度及びアンテナ切替制御手段１６０は、使用中の伝送速度よりも高い速度が利用でさない場合、すなわち、現在使用している伝送速度が最高速度であった場合には、現在の状態を維持する。
【００６８】
一方、伝送速度及びアンテナ切替制御手段１６０は、通信品質が悪いと判定された場合（条件Ｂが成立した場合）には、これまで使用していたアンテナとは異なるアンテナヘの切替を実行するとともに、アンテナ切替監視状態への状態遷移を行う。またこのとき、伝送速度及びアンテナ切替制御手段１６０は、アンテナ切替監視状態へ遷移してからの経過時間を計測するために、タイマーを始動する。
【００６９】
［速度増加監視状態］
伝送速度及びアンテナ切替制御手段１６０は、速度増加監視状態にある場合には、次の処理を行う。
【００７０】
伝送速度及びアンテナ切替制御手段１６０は、通信品質が不十分であると判定された場合（条件Ｃが成立した場合）には、タイマーを停止し、これまで使用していたアンテナの使用を継続しつつ、使用する伝送速度を一段階低下させ、通常状態への状態遷移を行う。
【００７１】
伝送速度及びアンテナ切替制御手段１６０は、通信品質が極めて良好であると判定された場合（条件Ａが成立した場合）には、使用中の伝送速度に応じて次の処理を行う。すなわち、伝送速度及びアンテナ切替制御手段１６０は、使用中の伝送速度よりもさらに高い速度が利用可能な場合には、これまで使用していたアンテナの使用を継続しつつ、使用する伝送速度を一段階増加させ、速度増加監視状態を維持する。
【００７２】
伝送速度及びアンテナ切替制御手段１６０は、使用中の伝送速度よりも高い速度が利用できない場合、すなわち、使用中の伝送速度が最高速度であった場合には、タイマーを停止後に通常状態への状態遷移を行う。
【００７３】
また、伝送速度及びアンテナ切替制御手段１６０は、速度増加監視状態に遷移する際に始動したタイマーがタイムアウトし、速度増加監視状態に遷移してからの経過時間が規定値Ｔ１を超えたことを検出した場合には、通常状態への状態遷移を行う。
【００７４】
［アンテナ切替監視状態］
伝送速度及びアンテナ切替制御手段１６０は、アンテナ切替監視状態にある場合には、次の処理を行う。
【００７５】
伝送速度及びアンテナ切替制御手段１６０は、通信品質が悪いと判定された場合（条件Ｂが成立した場合）には、これまで使用していたアンテナとは異なるアンテナへの切替を実行するとともに、使用中の伝送速度に応じて次の処理を行う。すなわち、使用中の伝送速度よりもさらに低い速度が利用可能な場合には、使用する伝送速度を一段階低下させ、速度低下監視状態への状態遷移を行う。
【００７６】
伝送速度及びアンテナ切替制御手段１６０は、このとき、速度低下監視状態へ遷移してからの経過時間を計測するために、タイマーをリセットし、再始動する。伝送速度及びアンテナ切替制御手段１６０は、使用中の伝送速度よりも低い速度が利用できない場合、すなわち、使用中の伝送速度が最低速度であった場合には、タイマーを停止し、通常状態への状態遷移を行う。
【００７７】
一方、伝送速度及びアンテナ切替制御手段１６０は、通信品質が極めて良好であると判定された場合（条件Ａが成立した場合）には、これまで使用していたアンテナの使用を縦続しつつ、タイマーを停止し、通常状態への状態遷移を行う。
【００７８】
また、伝送速度及びアンテナ切替制御手段１６０は、タイマーのタイムアウトにより、アンテナ切替監視状態へ遷移してからの経過時間が規定値Ｔ３を超えた場合には、通常状態への状態遷移を行う。
【００７９】
［速度低下監視状態］
伝送速度及びアンテナ切替制御手段１６０は、速度低下監視状態にある場合には、次の処理を行う。
【００８０】
伝送速度及びアンテナ切替制御手段１６０は、通信品質が悪いと判定された場合（条件Ｂが成立した場合）には、使用中の伝送速度に応じて次の処理を行う。すなわち、伝送速度及びアンテナ切替制御手段１６０は、使用中の伝送速度よりもさらに低い速度が利用可能な場合には、これまで使用していたアンテナの使用を継続しつつ、使用する伝送速度を一段階低下させ、速度低下監視状態を維持する。
【００８１】
伝送速度及びアンテナ切替制御手段１６０は、現在使用している伝送速度よりも低い速度が利用できない場合、すなわち、現在使用している伝送速度が最低速度であった場合には、タイマーを停止し、通常状態への遷移を行う。
一方、通信品質が極めて良好であると判定された場合（条件Ａが成立した場合）には、タイマーを停止し、通常状態への遷移を行う。
【００８２】
また、伝送速度及びアンテナ切替制御手段１６０は、タイマーのタイムアウトにより、速度低下監視状態へ遷移してからの経過時間が規定値Ｔ２を超えたことを検出した場合には、通常状態へ状態遷移する。
【００８３】
請求項４に記載の発明に係る無線パケット通信装置の構成例においては、伝送速度及びアンテナ切替制御手段１６０は、内部に複数の速度増加しきい値Ｕｉ（ｉ＝１、２、・・・、ｎ）、速度低下しきい値Ｄｉ（ｉ＝１、２、・・・、ｎ）、速度定着しきい値Ｆｉ（ｉ＝１、２、・・・、ｎ）を有し、伝送速度に応じた通信品質の判定の際に使用するしきい値の値を動的に変化させ、請求項３に記載の発明に係る無線パケット通信装置の構成例において説明した制御を行う。
【００８４】
たとえば、伝送速度及びアンテナ切替制御手段１６０は、伝送速度Ｒ３を使用している場合には、通信品質の判定において速度増加しきい値Ｕ３、速度低下しきい値Ｄ３、速度定着しきい値Ｆ３を使用する。
【００８５】
無線パケットを送信する際には、使用する伝送速度に応じて伝送効率が異なる場合が多い。このため、速度増加しきい値、速度低下しきい値、および速度定着しきい値をそれぞれある値に固定した場合、使用中の伝送速度によっては伝送効率の低下が問題となるが、請求項４に記載の発明に係る無線パケット通信装置の構成例によれば、効率の低下を抑制しつつ伝送速度の制御を行うことができる。
【００８６】
【発明の効果】
以上説明したように、本発明によれば、通信品質が良好であると判断して伝送速度を増加させた後、安定的に通信が行えなかった場合に、直ちに直前の伝送速度に戻すことができる。
【００８７】
したがって、本発明によれば、従来と比較して、伝送速度の制御における効率の劣化を低減することが可能となる。
【００８８】
よって、本発明によれば、周波数利用率を改善できるため、送受信器間のリンクの観点からはスループットの向上を図ることができ、また、システム全体の観点からはシステム容量の増加を図ることができる。
【図面の簡単な説明】
【図１】請求項１に記載の発明および請求項２に記載の発明に係る無線パケット通信装置の構成例を示す図である。
【図２】請求項３に記載の発明ならびに請求項４に記載の発明に係る無線パケット送受信装置の構成例を示す図である。
【図３】伝送速度制御手段１５０による、使用する伝送速度の決定方法を示す図である。
【図４】伝送速度及びアンテナ切替制御手段１６０による、使用する伝送速度および使用するアンテナの決定方法を示す図である
【図５】従来の無線パケット通信装置の例を示す図である。
【符号の説明】
１００無線プロトコル処理手段
１１０送信器
１２０受信器
１３０送受切替器
１４０、１４０ａ、１４０ｂアンテナ
１５０伝送速度制御手段
１６０伝送速度およびアンテナ切替制御手段
１７０アンテナ切替器
５００無線プロトコル処理手段
５１０送信器
５２０受信器
５３０送受切替器
５４０アンテナ
５５０伝送速度制御手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wireless packet communication device, and more particularly to a wireless packet communication device that selects one transmission rate from a plurality of available transmission rates and transmits data.
[0002]
[Prior art]
The wireless packet communication is a communication form adopted in various systems including the IEEE 802.11 wireless LAN. The physical layer of the IEEE802.11a standard or the IEEE802.11b standard has a transmission rate control unit that supports multi-rate, and this transmission rate control unit has an available transmission rate (for example, for each packet to be transmitted (for example, In the IEEE802.11a standard, eight transmission speeds of 6M, 9M, 12M, 18M, 24M, 36M, 48M, and 54Mbit / s are defined as available transmission speeds. Select and use.
[0003]
FIG. 5 is a diagram showing an example of a conventional wireless packet communication apparatus having the above transmission rate control means.
The transmission data input to the transmitter 510 is modulated at the transmission rate indicated by the transmission rate control means 550 and transmitted from the antenna 540 via the transmission / reception switch 530.
[0004]
In wireless communication, generally, when a higher transmission rate is used, higher communication quality is required.
Therefore, one communication quality is good from the viewpoint of performing stable communication at a certain transmission speed, but poor from the viewpoint of performing communication at a transmission speed one higher than the transmission speed. There are cases.
[0005]
For this reason, the transmission rate control means 550 has a rate increase threshold and a rate decrease threshold inside to control the transmission rate according to the quality of communication quality, and is input from the transmitter 510. The communication quality in the transmission path is determined by comparing the transmission notification of the transmission data and the reception notification of the arrival confirmation signal for the transmission data input from the receiver 520. The transmission power is controlled based on the noise power ratio (S / N: Signal to Noise ratio) and the determined quality of the communication quality.
[0006]
Specifically, the transmission rate control means 550 succeeds in data transmission when the arrival confirmation signal reception notification corresponding to the transmission notification is input within a certain time after the transmission notification is input. Judge that.
[0007]
The transmission rate control means 550 determines that the communication quality is very good when the transmission of the wireless packet has succeeded continuously for the number of times specified by the rate increase threshold value, and the transmission to be used. Control is performed to increase the speed by one step.
[0008]
On the other hand, the transmission rate control means 550 determines that the communication quality is extremely poor when the transmission of the wireless packet fails continuously for the number of times specified by the rate decrease threshold, and the transmission to be used. Control to reduce the speed one step.
[0009]
In this case, in the conventional transmission rate control means 550 in the conventional wireless packet communication, even when the communication quality is improved, the conditions for increasing the transmission rate are strict and the transmission rate is frequently changed. There are also those that prevent communication and stabilize communication.
[0010]
[Problems to be solved by the invention]
However, the conventional wireless packet communication device that determines the communication quality from the past data transmission result and determines the transmission rate based on the determined communication quality, that is, based on the transmission of data at a certain transmission rate In the conventional wireless packet communication device that determines the communication quality and increases the transmission rate of the next transmission data based on the determined communication quality, the communication quality is the transmission rate after the increase in the transmission rate. It may be inferior from the viewpoint of communication.
[0011]
In this case, the transmission / reception side in the conventional wireless packet communication apparatus cannot correctly demodulate the transmitted data, and the arrival confirmation is not returned from the reception side to the transmission side.
On the other hand, the transmission side in the conventional wireless packet communication apparatus does not return the transmission rate to the previous value unless the arrival confirmation for the transmission data is not continuously returned over a certain number of times.
[0012]
Therefore, in the conventional wireless packet communication device, there may occur a situation in which all data transmissions until the transmission rate returns to the previous value will fail.
Therefore, in the conventional wireless packet communication device, a reduction in throughput is a serious problem from the viewpoint of a communication link between transmission and reception, and a reduction in system capacity from the viewpoint of the entire system such as a wireless LAN. It was.
[0013]
In view of the above circumstances, an object of the present invention is to provide a wireless packet communication device capable of improving throughput and increasing system capacity.
[0014]
[Means for Solving the Problems]
According to the present invention, the above problem is solved by the means described in the claims.
[0015]
That is, the invention according to claim 1 is a transmission rate control means for controlling a transmission rate of a transmission signal, and a radio packet signal obtained by modulating transmission data inputted according to a transmission rate designated by a control signal of the transmission rate control means. And a transmitter output terminal of the transmitter and a receiver input terminal of the receiver are connected, the transmitter output terminal is connected to the common terminal at the time of transmission, and the receiver input terminal is connected to the common terminal at the time of reception. A transmission / reception switch, a receiver connected to a reception input terminal of the transmission / reception switch, which demodulates a received radio packet signal and outputs reception data, an antenna, and a return of an arrival confirmation signal for correctly received data Wireless protocol processing means for processing a communication procedure,
The transmission rate control means determines the communication quality by comparing the transmission notification input from the transmitter with the reception notification of the arrival confirmation signal input from the receiver, and based on the result of the determination, In a wireless packet communication device that determines a transmission rate when generating a wireless packet signal to be transmitted next,
The transmission rate control means includes
There are three constants, a timer, a speed increase threshold value U, a speed decrease threshold value D, and a speed fixing threshold value F, and any one of a normal state, a speed increase monitoring state, and a speed decrease monitoring state. In state
As a result of comparing the transmission notification input from the transmitter and the reception confirmation signal reception notification input from the receiver in the normal state, the successful transmission of the radio packet signal is increased in the speed. When observed continuously for the number of times specified by the threshold value U (hereinafter referred to as “the case of (a-1)”),
If it is judged that the communication quality is extremely good and a transmission speed higher than the transmission speed in use is available, the transmission speed to be used is changed to a one-step higher speed and the timer is started to enter the speed increase monitoring state. While the current state is maintained if the transmission rate in use is the highest available transmission rate,
As a result of comparing the transmission notification input from the transmitter and the reception notification signal reception notification input from the receiver in the normal state, the transmission failure of the radio packet signal is reduced in the speed. When observed continuously for the number of times specified by the threshold D (hereinafter referred to as “the case of (a-2)”),
If it is determined that the communication quality has deteriorated and a transmission speed lower than the transmission speed in use is available, the transmission speed to be used is changed to a transmission speed that is one step lower, and the timer is started to enter the speed reduction monitoring state. On the other hand, if the transmission rate in use is the lowest available transmission rate, keep the current state,
In the case of the normal state and in cases other than (a-1) and (a-2) above, the normal state is maintained,
In addition, as a result of comparing the transmission notification input from the transmitter with the arrival confirmation signal reception notification input from the receiver in the speed increase monitoring state, the wireless packet signal is continuously transmitted. When the success is less than the number of times specified by the speed fixing threshold F (hereinafter referred to as “(b-1)”),
Change the transmission speed to be used to a lower transmission speed and stop the timer to make a transition to the normal state.
As a result of comparing the transmission notification input from the transmitter and the reception confirmation signal reception notification input from the receiver in the speed increase monitoring state, a successful transmission of a radio packet signal indicates the speed increase. When observed continuously for the number of times specified by the threshold value U (hereinafter referred to as “(b-2)”),
If it is judged that the communication quality is extremely good and a transmission rate higher than the transmission rate in use is available, the transmission rate to be used is changed to one step higher, and the current state is maintained. If the medium transmission rate is the highest available transmission rate, stop the timer and make a transition to the normal state,
When it is in the speed increase monitoring state and it is confirmed that the elapsed time after the transition to this state has exceeded the specified value T1 due to the timeout of the timer (hereinafter referred to as “(b-3)”) To the normal state,
In the speed increase monitoring state and in cases other than (b-1), (b-2) and (b-3), the speed increase monitoring state is maintained.
Further, as a result of comparing the transmission notification input from the transmitter with the reception notification of the arrival confirmation signal input from the receiver in the speed decrease monitoring state, the transmission failure of the radio packet signal is When observed continuously for the number of times specified by the speed decrease threshold D (hereinafter referred to as “the case of (c-1)”),
If it is determined that the communication quality has deteriorated and a transmission speed lower than the transmission speed in use is available, the transmission speed used is changed to a lower speed to maintain the current state. If the transmission rate is the lowest available transmission rate, stop the timer and make a transition to the normal state,
As a result of comparing the transmission notification input from the transmitter and the notification of arrival of the arrival confirmation signal input from the receiver in the speed decrease monitoring state, the successful transmission of the radio packet signal increases the speed. When observed continuously for the number of times specified by the threshold value U (hereinafter referred to as “the case of (c-2)”),
Judge that the communication quality is very good, stop the timer and make a transition to the normal state,
When it is confirmed that the elapsed time after transition to this state has exceeded a specified value T2 due to the time-out of the timer in the speed reduction monitoring state (hereinafter referred to as “case (c-3)”) To the normal state,
Maintaining the speed reduction monitoring state in the case of the speed reduction monitoring state and in cases other than (c-1), (c-2) and (c-3). A wireless packet communication device characterized by the above.
[0016]
According to the first aspect of the present invention, the transmission rate control means has a transmission rate fixing threshold, unlike the conventional case, and after determining that the communication quality is good and increasing the transmission rate, When stable communication cannot be performed, control is immediately performed to return to the previous transmission rate.
[0017]
According to the second aspect of the present invention, the transmission rate control means includes a rate increase threshold value Ui (i = 1, 2,..., N), a rate decrease threshold value Di (i = 1, 2,. .., N), speed fixing threshold Fi (i = 1, 2,..., N),
Further, the correspondence between the speed increase threshold value Ui (i = 1, 2,..., N) to be used and the transmission speed, the speed decrease threshold value Di (i = 1, 2,..., N) to be used. ) And the transmission speed, the correspondence between the speed fixing threshold Fi used (i = 1, 2,..., N) and the transmission speed,
Manage
2. The wireless packet communication according to claim 1, wherein the speed increase threshold value, the speed decrease threshold value, and the speed fixing threshold value are dynamically changed according to a currently used transmission speed. Device.
[0018]
According to the second aspect of the present invention, the transmission speed control means has a plurality of speed increase threshold values, speed decrease threshold values, and speed fixing threshold values, which are different from conventional ones. The speed increase threshold value, the speed decrease threshold value, and the speed fixing threshold value are selectively used according to the transmission speed.
[0019]
According to a third aspect of the present invention, the transmission speed and the antenna switching control means for controlling the transmission speed of the transmission signal and selection of the antenna to be transmitted, and the transmission speed designated by the control signal of the transmission speed and the antenna switching control means Transmitter that modulates input transmission data and generates a wireless packet signal, a transmission output terminal of the transmitter and a reception input terminal of the receiver are connected, and the transmission output terminal is connected to a common terminal at the time of transmission Sometimes a transmission / reception switch that connects the reception input terminal to a common terminal and a plurality of antennas are connected, and one antenna is selected from the plurality of antennas according to the control signal input from the transmission speed and the antenna switching control means. An antenna switch connected to the common terminal of the transmission / reception switch, and a received radio packet signal connected to the reception input terminal of the transmission / reception switch Comprising a receiver for outputting received data by demodulating a wireless protocol processing means for processing the communication procedure including the return of the arrival confirmation signal for the correctly received data and,
The transmission rate control means determines the communication quality by comparing the transmission notification input from the transmitter with the reception notification of the arrival confirmation signal input from the receiver, and based on the result of the determination, In a wireless packet communication device that determines a transmission rate when generating a wireless packet signal to be transmitted next,
The transmission speed control means has three constants of a speed increase threshold value U, a speed decrease threshold value D, a speed fixing threshold value F and a timer, and is in a normal state, an antenna switching monitoring state, and a speed increase monitoring. Is in one of the status or speed drop monitoring status,
As a result of comparing the transmission notification input from the transmitter with the notification of arrival of the arrival confirmation signal input from the receiver in the normal state, the transmission success of the radio packet signal is increased by the threshold. When observed continuously for the number of times specified by the value U (hereinafter referred to as “the case of (a2-1)”),
If it is judged that the communication quality is very good and a transmission speed higher than the transmission speed in use is available, the transmission speed to be used is changed to a one-step higher speed, and the timer is started to monitor the speed increase. On the other hand, if the transmission rate in use is the highest available transmission rate, maintain the normal state,
As a result of comparing the transmission notification input from the transmitter with the notification of arrival of the arrival confirmation signal input from the receiver in the normal state, the transmission failure of the radio packet signal is the threshold for reducing the speed. When observed continuously for the number of times specified by the value D (hereinafter referred to as “the case of (a2-2)”),
If it is determined that the communication quality has deteriorated and a transmission speed lower than the transmission speed in use is available, the transmission speed to be used is changed to a transmission speed that is one step lower, and the timer is started to enter the speed reduction monitoring state. Make a transition, while if the current transmission rate is the lowest available, keep the current state,
In the normal state and in cases other than (a2-1) and (a2-2), the normal state is maintained,
As a result of comparing the transmission notification input from the transmitter with the notification of arrival of the arrival confirmation signal input from the receiver in the speed increase monitoring state, continuous transmission of radio packet signals is successful. When the number of times specified by the speed fixing threshold F is not reached (hereinafter referred to as “(b2-1)”),
Change the transmission speed to be used to a lower transmission speed and stop the timer to make a transition to the normal state.
As a result of comparing the transmission notification input from the transmitter with the notification of arrival of the arrival confirmation signal input from the receiver in the speed increase monitoring state, the transmission success of the radio packet signal increases the speed. When observed continuously for the number of times specified by the threshold value U (hereinafter referred to as “the case of (b2-2)”),
If it is judged that the communication quality is extremely good and a transmission rate higher than the transmission rate in use is available, the transmission rate to be used is changed to one step higher, and the current state is maintained. If the medium transmission rate is the highest available transmission rate, stop the timer and make a transition to the normal state,
When it is in the speed increase monitoring state and it is confirmed that the elapsed time after transition to this state has exceeded the specified value Tl due to the timeout of the timer (hereinafter referred to as “(b2-3)” To the normal state,
In the speed increase monitoring state and in cases other than (b2-1), (b2-2) and (b2-3), the speed increase monitoring state is maintained.
As a result of comparing the transmission notification input from the transmitter with the reception notification of the arrival confirmation signal input from the receiver in the antenna switching monitoring state, the successful transmission of the radio packet signal increases the speed. When observed continuously for the number of times specified by the threshold value U (hereinafter referred to as “the case of (c2-1)”),
Judge that the communication quality is very good, stop the timer and make a transition to the normal state,
As a result of comparing the transmission notification input from the transmitter with the notification of arrival of the arrival confirmation signal input from the receiver in the antenna switching monitoring state, the transmission failure of the radio packet signal is reduced in speed. When observed continuously for the number of times specified by the threshold D (hereinafter referred to as “(c2-2)”),
If it is judged that the communication quality has deteriorated, switching to an antenna different from the antenna used so far is performed, and if a transmission speed lower than the transmission speed in use is available, the transmission speed to be used is changed. Change to a lower transmission rate and restart the timer to make a transition to the speed drop monitoring state. On the other hand, if the transmission speed in use is the lowest, stop the timer and return to the normal state. Make a transition,
When it is in the antenna switching monitoring state and it is confirmed that the elapsed time after transition to this state has exceeded the specified value T3 due to the timeout of the timer (hereinafter referred to as “(c2-3)” )) Performs a state transition to the normal state,
In the antenna switching monitoring state, and in the cases other than (c2-1), (c2-2) and (c2-3), the antenna switching monitoring state is maintained.
As a result of comparing the transmission notification input from the transmitter with the notification of arrival of the arrival confirmation signal input from the receiver in the speed reduction monitoring state, the transmission failure of the radio packet signal is the speed reduction. When observed continuously for the number of times specified by the threshold D (hereinafter referred to as “(d2-1)”),
If it is judged that the communication quality has deteriorated and a transmission speed lower than the transmission speed currently in use is available, the transmission speed to be used is changed to one step lower, and the current state is maintained. If the transmission rate being used is the lowest available transmission rate, the timer is stopped and transition to the normal state is performed.
As a result of comparing the transmission notification input from the transmitter and the notification of arrival of the arrival confirmation signal input from the receiver in the speed decrease monitoring state, the successful transmission of the radio packet signal increases the speed. When observed continuously for the number of times specified by the threshold value U (hereinafter referred to as “(d2-2)”),
Judge that the communication quality is very good, stop the timer and make a transition to the normal state,
When it is in the speed reduction monitoring state and it is confirmed that the elapsed time after transition to this state has exceeded a specified value T2 due to the timeout of the timer (hereinafter referred to as “(d2-3)” To the normal state,
Maintaining the speed reduction monitoring state in the speed reduction monitoring state and in cases other than (d2-1), (d2-2) and (d2-3). A wireless packet communication device characterized by the above.
[0020]
According to the third aspect of the present invention, the transmission rate and antenna switching control means has a transmission rate fixing threshold, unlike the conventional case, and determines that the communication quality is good and increases the transmission rate. After that, when stable communication cannot be performed, control is performed to immediately return to the previous transmission rate.
[0021]
The invention according to claim 4 is characterized in that the transmission speed and the antenna switching control means are:
Speed increase threshold Ui (i = 1, 2,..., N), speed decrease threshold Di (i = 1, 2,..., N), speed fixing threshold Fi (i = 1) 2, ..., n),
Further, the correspondence between the speed increase threshold value Ui (i = 1, 2,..., N) to be used and the transmission speed, the speed decrease threshold value Di (i = 1, 2,..., N) to be used. ) And the transmission speed, the correspondence between the speed fixing threshold Fi used (i = 1, 2,..., N) and the transmission speed,
Manage
4. The wireless packet communication according to claim 3, wherein the speed increase threshold value, the speed decrease threshold value, and the speed fixing threshold value are dynamically changed according to a currently used transmission speed. Device.
[0022]
According to the fourth aspect of the present invention, the transmission speed and antenna switching control means has a plurality of speed increase threshold values, speed decrease threshold values, and speed fixing threshold values, which are different from conventional ones. When the quality is determined, the speed increase threshold value, the speed decrease threshold value, and the speed fixing threshold value are properly used according to the transmission speed being used.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
<Embodiment of Invention of Claim 1 and Embodiment of Claim 2>
FIG. 1 is a diagram showing a configuration example of a wireless packet communication apparatus according to the invention described in claim 1 and the invention described in claim 2.
[0024]
The transmission data is input to the transmitter 110 via the wireless protocol processing means 100 and modulated to a radio frequency. At this time, the transmitter 110 performs modulation at the rate instructed by the transmission rate control unit 150 and outputs a transmission notification to the transmission rate control unit 150 after the transmission is completed.
[0025]
The wireless packet signal generated by the transmitter 110 is input to the transmission / reception switch 130. The transmission / reception switch 130 outputs the input wireless packet signal to a common terminal to which the antenna 140 is connected when transmitting the wireless packet signal.
[0026]
On the other hand, the transmission / reception switch 130 inputs the reception signal from the antenna 140 connected to the common terminal to the receiver 120 when receiving the wireless packet signal. The receiver 120 outputs data to the wireless protocol processing hand throw 100 when the input wireless packet signal can be correctly demodulated.
[0027]
When the output signal of the receiver 120 is input, the wireless protocol processing unit 100 sends an arrival confirmation signal to the wireless packet communication apparatus that has transmitted the data via the transmitter 110, the transmission / reception switch 130, and the antenna 140. Send to.
[0028]
When receiving the arrival confirmation signal for the transmitted data via the antenna 140, the receiver 120 of the wireless packet communication apparatus that has transmitted the data inputs this reception notification to the transmission rate control means 150.
[0029]
The transmission rate control means 150 considers that the transmission of data is successful when a reception notification corresponding to the transmission notification is returned, and fails when the reception notification corresponding to the transmission notification is not returned within a specified time. It is considered that
[0030]
In the configuration example of the wireless packet communication device according to the first aspect of the invention, the transmission rate control hand throw 150 includes a speed increase threshold value U, a speed decrease threshold value D, and a speed fixing threshold value F inside. The communication quality between the transmitting and receiving apparatuses is determined from these threshold values and the history of past data transmission results.
[0031]
Here, the determination of the communication quality is performed as follows. That is, the transmission rate control means 150 indicates that the communication quality is extremely good when the arrival confirmation signal corresponding to the transmission data is continuously received for the number of times specified by the rate increase threshold value U. judge.
[0032]
Further, when the arrival confirmation signal corresponding to the transmission data is not continuously received within the predetermined time for the number of times defined by the speed reduction threshold D, it is determined that the communication quality is poor.
[0033]
Furthermore, if the transmission rate control means 150 continuously increases the transmission rate and data transmission fails for the number of times specified by the rate fixing threshold F, the communication quality is insufficient. Judge that there is. Then, the transmission rate control means 150 determines the transmission rate to be used based on the determination of the communication quality described above.
The transmission rate is determined by the method shown in FIG.
[0034]
FIG. 3 is a diagram showing a method for determining a transmission rate to be used by the transmission rate control means 150.
In the figure, when condition A is determined to be very good, condition B is determined to be poor communication quality, condition C is determined to be insufficient communication quality Means.
[0035]
The transmission rate control means 150 is in one of three states, a normal state, a rate increase monitoring state, and a rate decrease monitoring state, and controls the transmission rate while performing state transition according to the following conditions.
[0036]
[Normal state]
First, the transmission rate control means 150 performs the following process when in the normal state.
When it is determined that the communication quality is extremely good (when the condition A is satisfied), the transmission rate control unit 150 performs the following processing according to the currently used transmission rate. That is, when a higher transmission speed than the transmission speed in use is available, the transmission speed to be used is increased by one step and the state transition to the speed increase monitoring state is performed.
[0037]
Further, the transmission speed control means 150 starts a timer in order to measure the elapsed time after transitioning to the speed increase monitoring state.
The transmission rate control means 150 remains in the current state when a rate higher than the transmission rate in use is not available, that is, when the currently used transmission rate is the maximum rate.
[0038]
On the other hand, when it is determined that the communication quality is poor (when the condition B is satisfied), the transmission rate control means 150 performs the following process according to the transmission rate being used. That is, when a transmission rate lower than the transmission rate in use is available, the transmission rate to be used is reduced by one step and the state transition to the rate reduction monitoring state is performed.
[0039]
In addition, the transmission rate control means 150 starts a timer in order to measure the elapsed time since the transition to the rate drop monitoring state.
The transmission rate control means 150 maintains the current state when a rate lower than the transmission rate in use is not available, that is, when the currently used transmission rate is the lowest rate.
[0040]
[Speed increase monitoring status]
Also, the transmission rate control means 150 performs the following process when in the rate increase monitoring state.
[0041]
When it is determined that the communication quality is insufficient (when the condition C is satisfied), the transmission rate control unit 150 stops the timer that is started when the current state is changed, and sets the transmission rate to be used. While lowering by one step, state transition to the normal state is performed.
[0042]
When it is determined that the communication quality is extremely good (when the condition A is satisfied), the transmission rate control unit 150 performs the following processing according to the transmission rate being used.
That is, when a transmission rate higher than the transmission rate in use is available, the transmission rate to be used is increased by one step and the speed increase monitoring state is maintained.
[0043]
On the other hand, the transmission speed control means 150 stops the timer when the transmission speed higher than the transmission speed in use is not available, that is, when the transmission speed in use is the maximum speed, and returns to the normal state. Make a transition.
[0044]
Also, the transmission rate control means 150 detects that the timer started when transitioning to the rate increase monitoring state has timed out and the elapsed time since transitioning to the current state has exceeded the specified value T1. The state transition to the normal state is performed.
[0045]
[Deceleration monitoring status]
The transmission rate control means 150 performs the following processing when in the rate drop monitoring state.
When it is determined that the communication quality is poor (when the condition B is satisfied), the transmission rate control unit 150 performs the following process according to the transmission rate being used. That is, when a transmission rate lower than the transmission rate in use is available, the transmission rate to be used is reduced by one step and the speed reduction monitoring state is maintained.
[0046]
The transmission rate control means 150 stops the timer and changes the state to the normal state when a transmission rate lower than the transmission rate in use is not available, that is, when the transmission rate in use is the lowest rate. Do.
[0047]
On the other hand, when it is determined that the communication quality is extremely good (when the condition A is satisfied), the transmission rate control unit 150 stops the timer and performs the state transition to the normal state.
[0048]
In addition, when the transmission speed control unit 150 detects that the elapsed time from the transition to the speed decrease monitoring state exceeds the specified value T2 due to the timeout of the timer, the transmission speed control unit 150 performs the state transition to the normal state.
[0049]
In the configuration example of the wireless packet communication device according to the second aspect of the invention, the transmission rate control means 150 includes a plurality of rate increase thresholds Ui (i = 1, 2,..., N), Communication speed according to the transmission speed with a speed drop threshold Di (i = 1, 2,..., N) and a speed fixing threshold Fi (i = 1, 2,..., N). The above control is performed by dynamically changing the threshold value used in the determination.
For example, when the transmission speed R3 is used, the transmission speed control means 150 uses the speed increase threshold value U3, the speed decrease threshold value D3, and the speed fixing threshold value F3 in determining the communication quality.
[0050]
When transmitting a wireless packet, the transmission efficiency often varies depending on the transmission rate used. For this reason, when the speed increase threshold value, the speed decrease threshold value, and the speed fixing threshold value are each fixed to a certain value, a decrease in transmission efficiency becomes a problem depending on the transmission speed in use. According to the transmission rate control means 150 in the configuration example of the wireless packet communication device according to the invention described above, the transmission rate can be controlled while suppressing a decrease in efficiency.
[0051]
<Embodiment of Invention of Claim 3 and Embodiment of Invention of Claim 4>
FIG. 2 is a diagram illustrating a configuration example of a wireless packet communication device according to the invention described in claim 3 and the invention described in claim 4.
[0052]
The transmission data is input to the transmitter 110 via the wireless protocol processing means 100 and modulated to a radio frequency. At this time, the transmitter 110 performs modulation at the transmission rate and the rate instructed by the antenna switching control unit 160, and outputs a transmission notification to the transmission rate and antenna switching control unit 160 after the transmission is completed.
[0053]
The wireless packet signal generated by the transmitter 110 is input to the transmission / reception switch 130. The transmission / reception switch 130 outputs the input wireless packet signal to the common terminal to which the antenna switch 170 is connected when transmitting the wireless packet signal.
[0054]
The antenna switching unit 170 selects one antenna from the plurality of connected antennas 140a and 140b based on the transmission rate and the control signal input from the antenna switching control means 160, and transmits a radio packet signal.
[0055]
On the other hand, the transmission / reception switch 130 inputs the reception signal from the antenna switch 170 connected to the common terminal to the receiver 120 when receiving the wireless packet signal.
If the input radio packet signal can be correctly demodulated, the receiver 120 outputs the demodulated data to the radio protocol processing means 100.
[0056]
When the demodulated data is input, the wireless protocol processing unit 100 transmits the wireless packet communication through the transmitter 110, the transmission / reception switch 130, the antenna switch 170, the antenna 140a or the antenna 140b. An arrival confirmation signal is transmitted to the apparatus.
[0057]
When the receiver 120 in the wireless packet communication apparatus that has transmitted the data receives the arrival confirmation signal for the transmitted data via the antenna 140a or the antenna 140b, the antenna switch 170, and the transmission / reception switch 130, the reception notification Is provided to the transmission rate control means 150.
[0058]
The transmission rate control means 150 considers that data transmission is successful when a reception notification corresponding to the transmission notification is returned, and fails when the reception notification corresponding to the transmission notification is not returned within a specified time. It is considered that it did.
[0059]
In the configuration example of the wireless packet communication device according to the second aspect of the present invention, the transmission speed and antenna switching control means 160 includes a speed increase threshold U, a speed decrease threshold D, and a speed fixing threshold. F, and the communication quality between the transmitting and receiving apparatuses is determined from these threshold values and the history of past data transmission results.
[0060]
Here, the determination of the communication quality is performed as follows.
When the transmission speed and antenna switching control means 160 continuously receives the arrival confirmation signal corresponding to the transmission data for the number of times specified by the speed increase threshold value U, the communication quality is very good. judge.
[0061]
Also, the transmission rate and antenna switching control means 160 performs communication if the arrival confirmation signal corresponding to the transmission data is not continuously received within the predetermined time for the number of times specified by the speed decrease threshold D. Judge that the quality is poor.
Further, after the transmission speed and the antenna switching control means 160 increase the transmission speed, if the data transmission fails continuously for the number of times specified by the speed fixing threshold value F, the communication quality is improved. Judged to be insufficient.
[0062]
The transmission speed and antenna switching control means 160 determines the transmission speed to be used and the antenna to be used based on the determination of the communication quality described above.
The transmission speed to be used and the antenna to be used are determined by the method shown in FIG.
[0063]
FIG. 4 is a diagram showing a method for determining the transmission speed to be used and the antenna to be used by the transmission speed and antenna switching control means 160.
In the same figure, when it is determined that the communication quality is extremely good in the condition A, the communication quality is determined to be insufficient with the condition C when the communication quality is determined to be poor in the condition B. Means the case.
[0064]
The transmission speed / antenna switching control means 160 is in one of four states: a normal state, a speed increase monitoring state, an antenna switching monitoring state, and a speed reduction monitoring state. And antenna switching control.
[0065]
[Normal state]
The transmission speed and antenna switching control means 160 performs the following processing when in the normal state.
[0066]
When it is determined that the communication quality is extremely good (when the condition A is satisfied), the transmission speed and antenna switching control unit 160 performs the following process according to the transmission speed in use. That is, when a higher transmission speed than the transmission speed in use is available, the transmission speed to be used is increased by one step while continuing to use the antenna that has been used so far, and the speed increase monitoring state is entered. Perform state transition.
[0067]
At this time, the transmission speed and antenna switching control means 160 starts a timer in order to measure the elapsed time since the transition to the speed increase monitoring state.
The transmission speed and antenna switching control means 160 maintains the current state when a speed higher than the transmission speed in use is not used, that is, when the currently used transmission speed is the maximum speed. To do.
[0068]
On the other hand, when it is determined that the communication quality is poor (when the condition B is satisfied), the transmission speed and antenna switching control unit 160 performs switching to an antenna different from the antenna used so far. State transition to the antenna switching monitoring state is performed. At this time, the transmission rate and antenna switching control means 160 starts a timer in order to measure the elapsed time since the transition to the antenna switching monitoring state.
[0069]
[Speed increase monitoring status]
The transmission speed / antenna switching control means 160 performs the following processing when in the speed increase monitoring state.
[0070]
When it is determined that the communication quality is insufficient (condition C is satisfied), the transmission speed and antenna switching control means 160 stops the timer and continues to use the antenna that has been used so far. Meanwhile, the transmission speed to be used is reduced by one step, and the state transition to the normal state is performed.
[0071]
When it is determined that the communication quality is extremely good (when the condition A is satisfied), the transmission speed and antenna switching control unit 160 performs the following process according to the transmission speed in use. That is, the transmission speed and antenna switching control means 160, when a higher speed than the transmission speed in use is available, keeps using the antenna that has been used and keeps the transmission speed to be used. Increase the speed and maintain the speed increase monitoring state.
[0072]
When the transmission speed and the antenna switching control means 160 cannot use a higher speed than the transmission speed in use, that is, when the transmission speed in use is the maximum speed, the state is returned to the normal state after stopping the timer. Make a transition.
[0073]
Also, the transmission speed and antenna switching control means 160 detects that the timer started when transitioning to the speed increase monitoring state has timed out and the elapsed time since transitioning to the speed increase monitoring state has exceeded the specified value T1. If so, state transition to the normal state is performed.
[0074]
[Antenna switching monitoring status]
The transmission speed and antenna switching control means 160 performs the following processing when in the antenna switching monitoring state.
[0075]
When it is determined that the communication quality is poor (condition B is established), the transmission speed and antenna switching control means 160 performs switching to an antenna different from the antenna used so far and The following processing is performed according to the transmission speed. That is, when a transmission rate lower than the transmission rate in use is available, the transmission rate to be used is reduced by one step, and the state transition to the speed reduction monitoring state is performed.
[0076]
At this time, the transmission speed and antenna switching control means 160 resets and restarts the timer in order to measure the elapsed time since the transition to the speed reduction monitoring state. When the transmission speed and antenna switching control means 160 cannot use a speed lower than the transmission speed being used, that is, when the transmission speed being used is the lowest speed, the transmission speed and antenna switching control means 160 stops the timer and returns to the normal state. Perform state transitions.
[0077]
On the other hand, when it is determined that the communication quality is extremely good (when the condition A is satisfied), the transmission speed and antenna switching control means 160 continues the use of the antenna used so far, Is stopped and state transition to the normal state is performed.
[0078]
Also, the transmission speed and antenna switching control means 160 performs state transition to the normal state when the elapsed time after transitioning to the antenna switching monitoring state exceeds the specified value T3 due to timer timeout.
[0079]
[Deceleration monitoring status]
The transmission speed and antenna switching control means 160 performs the following process when in the speed reduction monitoring state.
[0080]
When it is determined that the communication quality is poor (when the condition B is satisfied), the transmission speed and antenna switching control unit 160 performs the following process according to the transmission speed in use. That is, when the transmission speed and antenna switching control means 160 can use a speed lower than the transmission speed in use, the transmission speed and antenna switching control means 160 keeps using the antenna that has been used up to now, Decrease the stage and maintain the speed reduction monitoring state.
[0081]
The transmission speed and antenna switching control means 160 stops the timer when a speed lower than the currently used transmission speed is not available, that is, when the currently used transmission speed is the lowest speed, Transition to the normal state.
On the other hand, when it is determined that the communication quality is extremely good (when the condition A is satisfied), the timer is stopped and a transition to the normal state is performed.
[0082]
Also, when the transmission speed and antenna switching control means 160 detects that the elapsed time after transitioning to the speed drop monitoring state exceeds the specified value T2 due to a timer timeout, the state transitions to the normal state. .
[0083]
In the configuration example of the wireless packet communication device according to the fourth aspect of the invention, the transmission rate and antenna switching control unit 160 includes a plurality of rate increase threshold values Ui (i = 1, 2,... n), speed reduction threshold Di (i = 1, 2,..., n), speed fixing threshold Fi (i = 1, 2,..., n), and according to the transmission speed The threshold value used in determining the communication quality is dynamically changed, and the control described in the configuration example of the wireless packet communication device according to the invention of claim 3 is performed.
[0084]
For example, when the transmission speed / antenna switching control means 160 uses the transmission speed R3, the speed increase threshold value U3, the speed decrease threshold value D3, and the speed fixing threshold value F3 are determined in communication quality determination. use.
[0085]
When transmitting a wireless packet, the transmission efficiency often varies depending on the transmission rate used. For this reason, when the speed increase threshold, the speed decrease threshold, and the speed fixing threshold are each fixed to a certain value, a decrease in transmission efficiency becomes a problem depending on the transmission speed in use. According to the configuration example of the wireless packet communication device according to the invention described above, it is possible to control the transmission rate while suppressing a decrease in efficiency.
[0086]
【The invention's effect】
As described above, according to the present invention, when the communication quality is determined to be good and the transmission rate is increased, when the communication cannot be stably performed, the transmission rate is immediately returned to the previous transmission rate. it can.
[0087]
Therefore, according to the present invention, it is possible to reduce deterioration of efficiency in transmission rate control as compared with the conventional case.
[0088]
Therefore, according to the present invention, since the frequency utilization rate can be improved, the throughput can be improved from the viewpoint of the link between the transmitter and the receiver, and the system capacity can be increased from the viewpoint of the entire system. it can.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration example of a wireless packet communication device according to the invention described in claim 1 and the invention described in claim 2;
FIG. 2 is a diagram showing a configuration example of a radio packet transmitting / receiving apparatus according to the invention of claim 3 and the invention of claim 4;
FIG. 3 is a diagram showing a method for determining a transmission rate to be used by the transmission rate control means 150;
FIG. 4 is a diagram showing a method for determining a transmission speed to be used and an antenna to be used by the transmission speed and antenna switching control means 160;
FIG. 5 is a diagram illustrating an example of a conventional wireless packet communication device.
[Explanation of symbols]
100 Wireless protocol processing means
110 Transmitter
120 receiver
130 duplexer
140, 140a, 140b Antenna
150 Transmission rate control means
160 Transmission speed and antenna switching control means
170 Antenna switch
500 Wireless protocol processing means
510 transmitter
520 receiver
530 duplexer
540 antenna
550 Transmission rate control means

Claims

A transmission rate control unit for controlling a transmission rate of a transmission signal; a transmitter for modulating a transmission data input according to a transmission rate specified by a control signal of the transmission rate control unit to generate a radio packet signal; and A transmission output terminal and a reception input terminal of the receiver are connected, the transmission output terminal is connected to the common terminal at the time of transmission, and the reception input terminal is connected to the common terminal at the time of reception, and the reception of the transmission / reception switch A receiver connected to the input terminal for demodulating a received radio packet signal and outputting received data; an antenna; and a radio protocol processing means for processing a communication procedure including returning an arrival confirmation signal for correctly received data; With
The transmission rate control means determines the communication quality by comparing the transmission notification input from the transmitter with the reception notification of the arrival confirmation signal input from the receiver, and based on the result of the determination, In a wireless packet communication device that determines a transmission rate when generating a wireless packet signal to be transmitted next,
The transmission rate control means includes
There are three constants, a timer, a speed increase threshold value U, a speed decrease threshold value D, and a speed fixing threshold value F, and any one of a normal state, a speed increase monitoring state, and a speed decrease monitoring state. In state
As a result of comparing the transmission notification input from the transmitter and the reception confirmation signal reception notification input from the receiver in the normal state, the successful transmission of the radio packet signal is increased in the speed. When observed continuously for the number of times specified by the threshold value U (hereinafter referred to as “the case of (a-1)”),
If it is judged that the communication quality is extremely good and a transmission speed higher than the transmission speed in use is available, the transmission speed to be used is changed to a one-step higher speed and the timer is started to enter the speed increase monitoring state. While the current state is maintained if the transmission rate in use is the highest available transmission rate,
As a result of comparing the transmission notification input from the transmitter and the reception notification signal reception notification input from the receiver in the normal state, the transmission failure of the radio packet signal is reduced in the speed. When observed continuously for the number of times specified by the threshold D (hereinafter referred to as “the case of (a-2)”),
If it is determined that the communication quality has deteriorated and a transmission speed lower than the transmission speed in use is available, the transmission speed to be used is changed to a transmission speed that is one step lower, and the timer is started to enter the speed reduction monitoring state. On the other hand, if the transmission rate in use is the lowest available transmission rate, keep the current state,
In the case of the normal state and in cases other than (a-1) and (a-2) above, the normal state is maintained,
In addition, as a result of comparing the transmission notification input from the transmitter with the arrival confirmation signal reception notification input from the receiver in the speed increase monitoring state, the wireless packet signal is continuously transmitted. When the success is less than the number of times specified by the speed fixing threshold F (hereinafter referred to as “(b-1)”),
Change the transmission speed to be used to a lower transmission speed and stop the timer to make a transition to the normal state.
As a result of comparing the transmission notification input from the transmitter and the reception confirmation signal reception notification input from the receiver in the speed increase monitoring state, a successful transmission of a radio packet signal indicates the speed increase. When observed continuously for the number of times specified by the threshold value U (hereinafter referred to as “(b-2)”),
If it is judged that the communication quality is extremely good and a transmission rate higher than the transmission rate in use is available, the transmission rate to be used is changed to one step higher, and the current state is maintained. If the medium transmission rate is the highest available transmission rate, stop the timer and make a transition to the normal state,
When it is in the speed increase monitoring state and it is confirmed that the elapsed time after the transition to this state has exceeded the specified value T1 due to the timeout of the timer (hereinafter referred to as “(b-3)”) To the normal state,
In the speed increase monitoring state, and in cases other than (b-1), (b-2) and (b-3), the speed increase monitoring state is maintained, and As a result of comparing the transmission notification input from the transmitter with the reception notification of the arrival confirmation signal input from the receiver in the speed drop monitoring state, the transmission failure of the radio packet signal is When observed continuously for the number of times defined by the drop threshold D (hereinafter referred to as “in the case of (c-1)”),
If it is determined that the communication quality has deteriorated and a transmission speed lower than the transmission speed in use is available, the transmission speed used is changed to a lower speed to maintain the current state. If the transmission rate is the lowest available transmission rate, stop the timer and make a transition to the normal state,
As a result of comparing the transmission notification input from the transmitter and the notification of arrival of the arrival confirmation signal input from the receiver in the speed decrease monitoring state, the successful transmission of the radio packet signal increases the speed. When observed continuously for the number of times specified by the threshold value U (hereinafter referred to as “the case of (c-2)”),
Judge that the communication quality is very good, stop the timer and make a transition to the normal state,
When it is confirmed that the elapsed time after transition to this state has exceeded a specified value T2 due to the time-out of the timer in the speed reduction monitoring state (hereinafter referred to as “case (c-3)”) To the normal state,
The speed reduction monitoring state is maintained in the speed reduction monitoring state and in cases other than (c-1), (c-2) and (c-3),
A wireless packet communication device.

The transmission speed control means includes a speed increase threshold value Ui (i = 1, 2,..., N), a speed decrease threshold value Di (i = 1, 2,..., N), and speed fixing. Threshold Fi (i = 1, 2,..., N),
Further, the correspondence between the speed increase threshold value Ui (i = 1, 2,..., N) to be used and the transmission speed, the speed decrease threshold value Di (i = 1, 2,..., N) to be used. ) And the transmission speed, the correspondence between the speed fixing threshold Fi used (i = 1, 2,..., N) and the transmission speed,
Manage
2. The wireless packet communication according to claim 1, wherein the speed increase threshold value, the speed decrease threshold value, and the speed fixing threshold value are dynamically changed according to a currently used transmission speed. apparatus.

A transmission rate and antenna switching control means for controlling the transmission speed of a transmission signal and selection of an antenna to transmit, and wirelessly by modulating transmission data inputted according to the transmission speed specified by the control signal of the transmission speed and antenna switching control means Transmitter that generates a packet signal, the transmission output terminal of the transmitter and the reception input terminal of the receiver are connected, the transmission output terminal is connected to the common terminal at the time of transmission, and the reception input terminal is the common terminal at the time of reception A transmission / reception switch to be connected; a plurality of antennas connected; and a common terminal of the transmission / reception switch by selecting one of the plurality of antennas according to a control signal input from the transmission speed and antenna switching control means; Connected to the antenna switch to be connected and the reception input terminal of the transmission / reception switch, demodulates the received radio packet signal and outputs the received data. Comprising a receiver for a wireless protocol processing means for processing the communication procedure including the return of the arrival confirmation signal for the correctly received data and,
The transmission rate control means determines the communication quality by comparing the transmission notification input from the transmitter with the reception notification of the arrival confirmation signal input from the receiver, and based on the result of the determination, In a wireless packet communication device that determines a transmission rate when generating a wireless packet signal to be transmitted next,
The transmission speed control means has three constants of a speed increase threshold value U, a speed decrease threshold value D, a speed fixing threshold value F and a timer, and is in a normal state, an antenna switching monitoring state, and a speed increase monitoring. Is in one of the status or speed drop monitoring status,
As a result of comparing the transmission notification input from the transmitter with the notification of arrival of the arrival confirmation signal input from the receiver in the normal state, the transmission success of the radio packet signal is increased by the threshold. When observed continuously for the number of times specified by the value U (hereinafter referred to as “the case of (a2-1)”),
If it is judged that the communication quality is very good and a transmission speed higher than the transmission speed in use is available, the transmission speed to be used is changed to a one-step higher speed, and the timer is started to monitor the speed increase. On the other hand, if the transmission rate in use is the highest available transmission rate, maintain the normal state,
As a result of comparing the transmission notification input from the transmitter with the notification of arrival of the arrival confirmation signal input from the receiver in the normal state, the transmission failure of the radio packet signal is the threshold for reducing the speed. When observed continuously for the number of times specified by the value D (hereinafter referred to as “the case of (a2-2)”),
If it is determined that the communication quality has deteriorated and a transmission speed lower than the transmission speed in use is available, the transmission speed to be used is changed to a transmission speed that is one step lower, and the timer is started to enter the speed reduction monitoring state. Make a transition, while if the current transmission rate is the lowest available, keep the current state,
In the normal state and in cases other than (a2-1) and (a2-2), the normal state is maintained,
As a result of comparing the transmission notification input from the transmitter with the notification of arrival of the arrival confirmation signal input from the receiver in the speed increase monitoring state, continuous transmission of radio packet signals is successful. When the number of times specified by the speed fixing threshold F is not reached (hereinafter referred to as “(b2-1)”),
Change the transmission speed to be used to a lower transmission speed and stop the timer to make a transition to the normal state.
As a result of comparing the transmission notification input from the transmitter with the notification of arrival of the arrival confirmation signal input from the receiver in the speed increase monitoring state, the transmission success of the radio packet signal increases the speed. When observed continuously for the number of times specified by the threshold value U (hereinafter referred to as “the case of (b2-2)”),
If it is judged that the communication quality is extremely good and a transmission rate higher than the transmission rate in use is available, the transmission rate to be used is changed to one step higher, and the current state is maintained. If the medium transmission rate is the highest available transmission rate, stop the timer and make a transition to the normal state,
When it is in the speed increase monitoring state and it is confirmed that the elapsed time after transition to this state has exceeded the specified value Tl due to the timeout of the timer (hereinafter referred to as “(b2-3)” To the normal state,
In the speed increase monitoring state and in cases other than (b2-1), (b2-2) and (b2-3), the speed increase monitoring state is maintained.
As a result of comparing the transmission notification input from the transmitter with the reception notification of the arrival confirmation signal input from the receiver in the antenna switching monitoring state, the successful transmission of the radio packet signal increases the speed. When observed continuously for the number of times specified by the threshold value U (hereinafter referred to as “the case of (c2-1)”),
Judge that the communication quality is very good, stop the timer and make a transition to the normal state,
As a result of comparing the transmission notification input from the transmitter with the notification of arrival of the arrival confirmation signal input from the receiver in the antenna switching monitoring state, the transmission failure of the radio packet signal is reduced in speed. When observed continuously for the number of times specified by the threshold D (hereinafter referred to as “(c2-2)”),
If it is judged that the communication quality has deteriorated, switching to an antenna different from the antenna used so far is performed, and if a transmission speed lower than the transmission speed in use is available, the transmission speed to be used is changed. Change to a lower transmission rate and restart the timer to make a transition to the speed drop monitoring state. On the other hand, if the transmission speed in use is the lowest, stop the timer and return to the normal state. Make a transition,
When it is in the antenna switching monitoring state and it is confirmed that the elapsed time after transition to this state has exceeded the specified value T3 due to the timeout of the timer (hereinafter referred to as “(c2-3)” )) Performs a state transition to the normal state,
In the antenna switching monitoring state, and in the cases other than (c2-1), (c2-2) and (c2-3), the antenna switching monitoring state is maintained.
As a result of comparing the transmission notification input from the transmitter with the notification of arrival of the arrival confirmation signal input from the receiver in the speed reduction monitoring state, the transmission failure of the radio packet signal is the speed reduction. When observed continuously for the number of times specified by the threshold D (hereinafter referred to as “(d2-1)”),
If it is judged that the communication quality has deteriorated and a transmission speed lower than the transmission speed currently in use is available, the transmission speed to be used is changed to one step lower, and the current state is maintained. If the transmission rate being used is the lowest available transmission rate, the timer is stopped and transition to the normal state is performed.
As a result of comparing the transmission notification input from the transmitter and the notification of arrival of the arrival confirmation signal input from the receiver in the speed decrease monitoring state, the successful transmission of the radio packet signal increases the speed. When observed continuously for the number of times specified by the threshold value U (hereinafter referred to as “(d2-2)”),
Judge that the communication quality is very good, stop the timer and make a transition to the normal state,
When it is in the speed reduction monitoring state and it is confirmed that the elapsed time after transition to this state has exceeded a specified value T2 due to the timeout of the timer (hereinafter referred to as “(d2-3)” To the normal state,
The speed reduction monitoring state is maintained in the case of the speed reduction monitoring state, and in cases other than (d2-1), (d2-2) and (d2-3).
A wireless packet communication device.

The transmission speed and antenna switching control means are:
Speed increase threshold Ui (i = 1, 2,..., N), speed decrease threshold Di (i = 1, 2,..., N), speed fixing threshold Fi (i = 1) 2, ..., n),
Further, the correspondence between the speed increase threshold value Ui (i = 1, 2,..., N) to be used and the transmission speed, the speed decrease threshold value Di (i = 1, 2,..., N) to be used. ) And the transmission speed, the correspondence between the speed fixing threshold Fi used (i = 1, 2,..., N) and the transmission speed,
Manage
4. The wireless packet communication according to claim 3, wherein the speed increase threshold value, the speed decrease threshold value, and the speed fixing threshold value are dynamically changed according to a currently used transmission speed. apparatus.