JP2004328431A - Diversity receiving method and diversity circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a diversity circuit for obtaining satisfactory reception characteristics with simple structure by solving the problems of level fluctuation and phase rotation caused by fading in a digital mobile communication system. <P>SOLUTION: Receiving quality is improved by the diversity circuit with simple structure by constituting the diversity circuit so that it has a received signal level detection means for making the average value of the absolute values of any of in-phase component or quadrature component obtained by performing quadrature detection of the received signal into a received signal level; and a receiving branch selection means for comparing the received signal levels of a plurality of receiving branches obtained by the received signal level detection means and selecting data received from a receiving branch with the largest received signal level. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００９】
受信信号レベル１１４は、ダイバーシティ部及び自動利得制御部１１３へ入力される。ダイバーシティ部は、各受信ブランチからの受信信号レベルを比較し、最も受信信号レベルが大きいブランチからの受信データが最も信頼性が高いと判断し、そのブランチからの受信データを選択する（例えば、特許文献１を参照）。
【００１０】
【特許文献１】
特開平０６−９０２２７号公報
【００１１】
【発明が解決しようとする課題】
上記の従来技術の例のように、受信信号レベルを求める方法として、Ｉ信号及びＱ信号の２乗和の平方根を用いる方法が一般に多く用いられている。しかし、２乗や平方根を求める演算は、回路が複雑となり、規模も大きくなるという課題がある。
【００１２】
また、従来のダイバーシティ方式では、受信信号レベルのみならず、復調後のデータから求めた誤り率を使用するなど、さまざまな情報の組合せからブランチ選択を行う方法が用いられている。しかし、回路の小型化のために、受信信号レベルの検出方法を簡素化すると、ダイバーシティ回路での受信信号品質比較の精度が劣化してしまい、多くの情報から処理を行うために、制御が複雑となり、それを実現する回路も大きくなってしまうという課題がある。
【００１３】
また、受信回路をＬＳＩ化し、小型化を図るには、各処理部それぞれができるだけ簡易な構成で実現されることが要求される。
【００１４】
従って本発明は、無線通信システムにおいて、受信信号レベル検出方法を簡素化し、さらに位相変調信号復調処理時に容易に得られる位相誤差値をブランチ判定条件に加えることで、簡易な構成で受信品質の改善が実現できるダイバーシティ回路を提供することを目的とする。
【００１５】
【課題を解決するための手段】
この課題を解決するために本発明は、受信信号レベルの検出を、直交検波後の同相成分（Ｉ信号）または直交成分（Ｑ信号）の絶対値の平均のみから求めるように構成したものである。
【００１６】
また本発明は、位相変調信号復調処理時に容易に得られる位相誤差値をあらかじめ定めたシンボルデータ分累積し、複数ブランチ間の受信信号レベルの差が小さい場合は、さらにブランチ判定条件に位相誤差累積値を用いるように構成したものである。
【００１７】
これらにより、受信信号レベル検出回路を小型化でき、また、特に複雑な回路を付加することなく、ブランチ選択精度を高めることが可能となり、簡易な構成のダイバーシティ回路が得られる。
【００１８】
【発明の実施の形態】
本発明の請求項１に記載の発明は、受信信号を直交検波して得られた同相成分または直交成分のいずれかの絶対値の平均値を受信信号レベルとし、複数の受信ブランチ間で比較し、最も受信信号レベルの大きい受信ブランチからの受信データを選択するものであり、最も受信信号レベルの大きい受信ブランチからの受信データを選択することで、ブランチ選択精度の向上を図ると共に、受信信号レベルの検出回路を簡易な構成で実現することができるという作用を有する。
【００１９】
請求項２に記載の発明は、受信信号を直交検波して得られた同相成分または直交成分のいずれかの絶対値の平均値を受信信号レベルとして求め、位相変調信号を復調して得られる位相データを用いて、前記位相データの理想の位相からの位相誤差をあらかじめ定めたシンボルデータ分累積した位相誤差累積値を求め、前記受信信号レベルと位相誤差累積値とから受信ブランチからの受信データを選択するものであり、受信信号レベルと位相誤差累積値とから受信ブランチからの受信データを選択することにより、ブランチ選択精度の向上を図ると共に、受信信号レベルの検出回路を簡易な構成で実現することができるという作用を有する。
【００２０】
請求項３に記載の発明は、請求項１または２記載のダイバーシティ受信方法において、受信データの選択は、最も受信信号レベルの大きい受信ブランチの受信信号レベルと、それ以外の受信ブランチの受信信号レベルとの差があらかじめ定められた閾値より大きい場合は、最も受信信号レベルの大きい受信ブランチからの受信信号を選択することを特徴とするもので、最も受信信号レベルの大きい受信号とそれ以外の受信ブランチの受信信号レベルとの差を選択条件に加え、この差が受信信号品質を比較する上で有意な差である状況においてブランチ選択を行うことにより、ブランチ選択精度の向上を図ると共に、受信信号レベルの検出回路を簡易な構成で実現することができるという作用を有する。
【００２１】
請求項４に記載の発明は、請求項２記載のダイバーシティ受信方法において、受信データの選択は、最も受信信号レベルの大きい受信ブランチの受信信号レベルと、それ以外の受信ブランチの受信信号レベルとの差があらかじめ定められた閾値より小さい場合は、最も位相誤差累積値の小さい受信ブランチからの受信信号を選択することを特徴とするもので、最も受信信号レベルの大きい受信号とそれ以外の受信ブランチの受信信号レベルとの差を選択条件に加え、この差が受信信号品質を比較する上で有意な差でない状況においては、ブランチ選択条件を位相誤差累積値に切り替えることでブランチ選択を行うことにより、ブランチ選択精度の向上を図ると共に、受信信号レベルの検出回路を簡易な構成で実現することができるという作用を有する。
【００２２】
請求項５に記載の発明は、請求項２記載のダイバーシティ受信方法において、受信データの選択は、最も位相誤差累積値の小さい受信ブランチと、それ以外の受信ブランチとの位相誤差累積値の差があらかじめ定められた閾値より小さい受信ブランチが存在する場合は、該当受信ブランチ間の中で最も受信信号レベルの大きい受信ブランチを選択することを特徴とするもので、最も位相誤差累積値の小さい受信ブランチと、それ以外の受信ブランチとの位相誤差累積値の差を選択条件に加え、この差が受信信号品質を比較する上で有意な差でない状況においては、ブランチ選択条件を受信信号レベルに切り替えることでブランチ選択を行うことにより、ブランチ選択精度の向上を図ると共に、受信信号レベルの検出回路を簡易な構成で実現することができるという作用を有する。
【００２３】
請求項６に記載の発明は、請求項１乃至５のいずれかに記載のダイバーシティ受信方法において、受信した信号を用いてフレーム同期処理を行った結果、フレーム同期の確立の成功または不成功のいずれかを示すフレーム同期判定結果より、フレーム同期の確立の成功した受信ブランチの候補から選択することを特徴とするもので、フレーム同期外れと判定された受信ブランチを、受信ブランチ選択の候補から除外することで、ブランチ選択精度の向上を図ることができるという作用を有する。
【００２４】
請求項７に記載の発明は、受信信号を直交検波して得られた同相成分または直交成分のいずれかの絶対値の平均値を受信信号レベルとする受信信号レベル検出手段と、前記受信信号レベル検出手段より得られる受信信号レベルを、複数の受信ブランチ間で比較し、最も受信信号レベルの大きい受信ブランチからの受信データを選択する受信ブランチ選択手段とを有するもので、最も受信信号レベルの大きい受信ブランチからの受信データを選択することで、ブランチ選択精度の向上を図ると共に、受信信号レベルの検出回路を簡易な構成で実現することができるという作用を有する。
【００２５】
請求項８に記載の発明は、受信信号を直交検波して得られた同相成分または直交成分のいずれかの絶対値の平均値を受信信号レベルとする受信信号レベル検出手段と、位相変調信号を復調して得られる位相データを用いて、前記位相データの理想の位相からの位相誤差を検出する位相誤差検出手段と、前記位相誤差をあらかじめ定めたシンボルデータ分累積した位相誤差累積値を求める位相誤差累積手段と、前記受信信号レベル検出手段より得られる受信信号レベルと前記位相誤差累積手段より得られる位相誤差累積値とから受信ブランチからの受信データを選択する受信ブランチ選択手段とを有することを特徴とするもので、受信信号レベルと位相誤差累積値とから受信ブランチからの受信データを選択することにより、ブランチ選択精度の向上を図ると共に、受信信号レベルの検出回路を簡易な構成で実現することができるという作用を有する。
【００２６】
請求項９に記載の発明は、請求項７記載のダイバーシティ回路において、受信ブランチ選択手段は、最も受信信号レベルの大きい受信ブランチの受信信号レベルと、それ以外の受信ブランチの受信信号レベルとの差があらかじめ定められた閾値より大きい場合は、最も受信信号レベルの大きい受信ブランチからの受信信号を選択することを特徴とするもので、最も受信信号レベルの大きい受信号とそれ以外の受信ブランチの受信信号レベルとの差を選択条件に加え、この差が受信信号品質を比較する上で有意な差である状況においてブランチ選択を行うことにより、ブランチ選択精度の向上を図ると共に、受信信号レベルの検出回路を簡易な構成で実現することができるという作用を有する。
【００２７】
請求項１０に記載の発明は、請求項８記載のダイバーシティ回路において、受信ブランチ選択手段は、最も受信信号レベルの大きい受信ブランチの受信信号レベルと、それ以外の受信ブランチの受信信号レベルとの差があらかじめ定められた閾値より小さい場合は、最も位相誤差累積値の小さい受信ブランチからの受信信号を選択することを特徴とするもので、最も受信信号レベルの大きい受信号とそれ以外の受信ブランチの受信信号レベルとの差を選択条件に加えることにより、この差が受信信号品質を比較する上で有意な差でない状況においては、ブランチ選択条件を位相誤差累積値に切り替えることでブランチ選択を行うことにより、ブランチ選択精度の向上を図ると共に、受信信号レベルの検出回路を簡易な構成で実現することができるという作用を有する。
【００２８】
請求項１１に記載の発明は、請求項８記載のダイバーシティ回路において、受信ブランチ選択手段は、最も位相誤差累積値の小さい受信ブランチと、それ以外の受信ブランチとの位相誤差累積値の差があらかじめ定められた閾値より小さい受信ブランチが存在する場合は、該当受信ブランチ間の中で最も受信信号レベルの大きい受信ブランチを選択することを特徴とするもので、最も位相誤差累積値の小さい受信ブランチと、それ以外の受信ブランチとの位相誤差累積値の差を選択条件に加え、受信信号品質を比較する上で、ブランチ間の位相誤差累積値の差が有意な差でない状況においては、ブランチ選択条件を受信信号レベルに切り替えることでブランチ選択を行うことにより、ブランチ選択精度の向上を図ると共に、受信信号レベルの検出回路を簡易な構成で実現することができるという作用を有する。
【００２９】
請求項１２に記載の発明は、請求項７乃至１１のいずれかに記載のダイバーシティ回路において、さらに、受信した信号を用いてフレーム同期処理を行った結果、フレーム同期の確立の成功または不成功のいずれかを示すフレーム同期判定結果を出力するフレーム同期判定手段を具備し、前記フレーム同期判定手段より得られるフレーム同期判定結果より、フレーム同期の確立した受信ブランチの候補から選択することを特徴とするもので、フレーム同期外れと判定された受信ブランチを、受信ブランチ選択の候補から除外することで、ブランチ選択精度の向上を図ることができるという作用を有する。
【００３０】
請求項１３に記載の発明は、請求項８乃至１２のいずれかに記載のダイバーシティ回路において、同じ受信信号またはあらかじめ定めた時間差内の受信信号を基に求められた受信信号レベル、位相誤差累積値、フレーム同期判定結果、及び、受信データが、ダイバーシティ回路へ入力されるようにタイミングを調整するタイミング調整手段を有することを特徴とするもので、それぞれの信号を得るのに必要な処理時間の差を吸収する遅延量の遅延器の挿入することにより、各信号間の時間相関を高めることができ、ブランチ選択精度を向上させるという作用を有する。
【００３１】
請求項１４に記載の発明は、請求項７乃至１３のいずれかに記載のダイバーシティ回路からの受信データを受信することを特徴とする受信装置で、信頼性の高い受信装置を実現することができるという作用を有する。
【００３２】
請求項１５に記載の発明は、請求項１４に記載の受信装置と、フレーム同期用データを含むデータを位相変調して送信するの送信装置とを有することを特徴とするもので、信頼性の高い通信装置を実現することができるという作用を有する。
【００３３】
以下、本発明の実施の形態について、図を用いて説明する。
【００３４】
（実施の形態１）
図１は、本発明の実施の形態１におけるダイバーシティ回路を用いた受信装置の構成を示すブロック図である。これは、二つのブランチａ，ｂから構成される受信装置の例である。
【００３５】
図１において、４００ａ、ｂは受信ＩＦ信号４０１ａ、４０１ｂより得られる受信信号レベル４２１ａ，ｂ及びフレーム同期部４１８ａ，ｂより得られた復調後の受信データ４２４ａ、ｂをそれぞれ生成するブランチａ，ｂ、４２５は各ブランチにおける受信信号レベル及び復調後の受信データを用いてブランチ選択をするダイバーシティ部である。各ブランチとも、アンテナ４２７、ＲＦ部４２８、ＩＦアンプ４０２、Ａ／Ｄ変換部４０４、直交検波部４０６、チャネルフィルタ部４０９、受信信号レベル検出部４２２、自動利得制御部４１９と、復調処理部である位相変換部４１２、位相検波部４１４、自動周波数制御部４１６及びフレーム同期部４１８とから構成されている。
【００３６】
上記のように構成された受信装置の動作について、以下に説明する。
【００３７】
受信ＩＦ信号４０１ａ、ｂは、ＩＦアンプ４０２ａ、ｂにて、目標レベルに近づくようにレベルを制御される。ＩＦアンプ４０２ａ、ｂの利得は、自動利得制御部４１９ａ、ｂにより求められた利得制御信号４２０ａ、ｂにより決定される。ＩＦアンプ出力信号４０３ａ、ｂはＡ／Ｄ変換部４０４ａ、ｂでサンプリングされる。サンプリングにより得られたディジタルＩＦ信号４０５ａ、ｂは、直交検波部４０６ａ、ｂにより直交検波され、同相成分（Ｉ信号４０７ａ、ｂ）及び直交成分（Ｑ信号４０８ａ、ｂ）が得られる。
【００３８】
さらに、同相成分（Ｉ信号４０７ａ、ｂ）及び直交成分（Ｑ信号４０８ａ、ｂ）は、チャネルフィルタ部４０９ａ、ｂにおいて波形整形処理され、波形整形後の同相成分（Ｉ信号４１０ａ、ｂ）及び波形整形後の直交成分（Ｑ信号４１１ａ、ｂ）が得られる。Ｉ信号４１０ａ、ｂ及びＱ信号４１１ａ、ｂは、位相変換部４１２ａ、ｂにおいて位相データ４１３ａ、ｂに変換される。位相検波部４１４ａ、ｂは、この位相データ４１３ａ、ｂを用いて検波を行い、受信シンボルデータ４１５ａ、ｂが得られる。自動周波数制御部４１６ａ、ｂは、受信シンボルデータの位相情報から、位相誤差を検出し、これをあらかじめ定めたシンボルデータ分累積・平均化することで位相誤差補正量を求め、これをもとに受信シンボルデータを理想の信号点の位相に近づける。位相誤差を補正された受信シンボルデータ４１７ａ、ｂは、フレーム同期、ビット判定を行うフレーム同期部４１８ａ、ｂに渡され、その結果受信データ４２４ａ、ｂが得られる。
【００３９】
一方、受信ＩＦ信号４０１ａ、４０１ｂより得られる波形整形後の同相成分（Ｉ信号）または波形整形後の直交成分（Ｑ信号）のいずれかを受信信号レベル判定データ４２３ａ、ｂとして、受信信号レベル検出部４２２ａ，ｂに入力し、受信信号レベル４２１ａ、ｂを生成する。受信信号レベル４２１ａ、ｂは、自動利得制御部４１９ａ、ｂにおいて受信ＩＦ信号４０１ａ、ｂの入力レベル制御に使用される一方、ダイバーシティ部４２５にも入力され、
ダイバーシティ部４２５は、得られた受信信号レベル４２１ａ、ｂ及びフレーム同期部４１８ａ、ｂより得られた復調後の受信データ４２４ａ、ｂを用いた後述するダイバーシティ手順により、最も受信品質が良いブランチからの受信データ４２６が選択される。
【００４０】
次に、受信信号レベル検出部４２２ａ、ｂについて説明する。
【００４１】
図２は、ダイバーシティ回路を有する受信装置内の、１つのブランチにおけるＩＦアンプ１０２から復調処理部（位相変換部４１２ａ，ｂ〜フレーム同期部４１８ａ、ｂ）への入力までの詳細構成を示すブロック図である。
【００４２】
受信ＩＦ信号４０１は、ＩＦアンプ４０２にて、目標レベルに近づくようにレベルを制御される。ＩＦアンプ４０２の利得は、自動利得制御部４１３により求められた利得制御信号４１２により決定される。ＩＦアンプ出力信号４０３はＡ／Ｄ変換部４０４でサンプリングされる。サンプリングにより得られたディジタルＩＦ信号４０５は、直交検波部４０６により直交検波され、同相成分（Ｉ信号４０７）及び直交成分（Ｑ信号４０８）が得られる。さらに、同相成分（Ｉ信号４０７）及び直交成分（Ｑ信号４０８）は、チャネルフィルタ部４０９において波形整形処理され、波形整形後の同相成分（Ｉ信号４１０）及び波形整形後の直交成分（Ｑ信号４１１）が得られる。
【００４３】
Ｉ信号４１０及びＱ信号４１１は、復調処理に用いられる。さらにＩ信号４１０は、受信信号レベル検出部４２２に対しても入力される。受信信号レベル検出部４２２では、受信信号レベル演算部２０４において、Ｉ信号４１０の絶対値（：瞬時の受信信号レベル２０３）が求められる。瞬時の受信信号レベル２０３を平均処理部２０２により、あらかじめ定めたデータ分平均化し、受信信号レベル４２１として、ダイバーシティ部４２５及び自動利得制御部４１３へ出力する。
【００４４】
すなわち、受信信号レベル検出部４２２で求められる受信信号レベルは、（数２）によって求めることができる。
【００４５】
【数２】

【００４６】
なお、以上の説明では、受信信号レベル検出部４２２への受信信号レベル検出に、波形整形後の同相成分（Ｉ信号４１０）を用いた例で説明したが、波形整形後の直交成分（Ｑ信号４１１）を用いることでも実施可能である。
【００４７】
次に、前記のようにして得られた各ブランチの受信信号レベル４２１ａ，ｂを用いて、ブランチ選択を行うダイバーシティ部４２５のダイバーシティ手順について説明する。図３は、各ブランチにおける受信信号レベル及び復調後の受信データを用いてブランチ選択をするダイバーシティ部４２５の構成を示すブロック図である。
【００４８】
受信信号レベル比較部３０２は、全ブランチ（ブランチａ〜ブランチｎ）の受信信号レベル４２１ａ〜４２１ｎを比較し、最も受信信号レベルの大きいブランチが最も受信品質が良いと判定し、そのブランチを示すブランチ選択信号３０３を出力する。受信ブランチ選択部３０４は、各ブランチから渡された受信データ４２４１〜４２４ｎのうち、ブランチ選択信号３０３で示されたブランチからの受信データを、ダイバーシティ部４２５で選択した受信データ４２６として出力する。
【００４９】
以上説明したように、ダイバーシティ回路において、最も品質の良いブランチの受信データを選択する際に、受信信号レベルの検出を、直交検波後の同相成分（Ｉ信号）または直交成分（Ｑ信号）の絶対値の平均のみから求めるように構成したもので、受信信号レベル検出回路を小型化でき、ブランチ選択精度を高めることが可能となり、簡易な構成のダイバーシティ回路が得られる。
【００５０】
（実施の形態２）
図４に本発明の実施の形態２における受信装置のブロック構成図を示し、説明する。実施の形態２は、図４にその構成を示すように、実施の形態１とは受信シンボルデータの位相誤差の累積演算を行うダイバーシティ用の位相誤差累積部８０３ａ、ｂを設け、ダイバーシティ部８０４は受信信号レベル及び位相誤差累積値を用いて、最も受信品質が良いブランチを選択するところが異なるもので、異なるところを中心に説明する。
【００５１】
本実施の形態の発明の骨子は、自動利得制御用に受信信号レベル検出部４２２ａ，ｂで生成された受信信号レベル４２１ａ、ｂは、ダイバーシティ部８０４に対しても入力され、自動周波数制御部４１６ａ、ｂで生成された、受信シンボルデータ４１５ａ、ｂの位相誤差８０１ａ、ｂは、ダイバーシティ用の位相誤差累積部８０２ａ、ｂであらかじめ定められたシンボル数分累積され、位相誤差累積値８０３ａ、ｂとしてダイバーシティ部８０４に対して入力される。ダイバーシティ部８０４は、受信信号レベル４２１ａ、ｂ、及び、位相誤差累積値８０３ａ、ｂを用いて、前記のダイバーシティ手順により、最も受信品質が良いブランチを選択し、選択されたブランチからの受信データ８０５を出力するものである。
【００５２】
次に、図６に自動周波数制御部４１６ａ，ｂ及び位相誤差累積部８０２のブロック構成図の例を示し、以下に説明する。一般に送受信装置間で用いられるキャリア周波数の誤差を補正するために、受信装置に自動周波数制御部が搭載されるが、自動周波数制御部によるキャリア周波数誤差補正は、次に説明する位相誤差を用いて行うことができる。
【００５３】
図５は、受信した４相位相変調信号の位相検波後の信号点配置の一例を示したものであり、取り得る４つの理想の信号点配置を、５０１、５０２、５０３、５０４の◎で示している。ここでは、受信シンボルデータの信号点配置を５０６（●）とする。４相位相変調の場合は、受信シンボルデータの位相が、理想の信号点の位相に対し±π／４より小さい誤差であれば、正しく復調できる。したがって、信号点配置５０１のシンボルデータを送信した結果、受信シンボルデータが５０６（●）のように、理想の信号点配置５０１に対する位相誤差５０７が、±π／４より小さければ（第１象現５０５内に存在すれば）、理想の信号点配置５０１に相当するシンボルデータが送信されたと判定できる。
【００５４】
直交検波、波形整形後のＩ信号４１０、Ｑ信号４１１は、位相変換部４１２において位相データ４１３に変換される。位相検波部４１４は、この位相データ４１３を用いて検波を行い、受信シンボルデータ４１５が得られる。自動周波数制御部４１６は、受信シンボルデータ４１５の位相情報から、位相誤差検出部６０５において、前記のように理想の信号点からの位相誤差６０４を検出し、位相誤差累積・平均化・補正量演算部６０３においてあらかじめ定めたシンボルデータ分だけ位相誤差６０４を累積及び平均化し、受信シンボルデータを理想の信号点の位相に近づけるための位相誤差補正量６０２を求める。求められた位相誤差補正量６０２は、位相検波部４１４の出力である受信シンボルデータ４１５を補正部６０６で補正する。位相誤差を補正された受信シンボルデータ６０１は、フレーム同期、ビット判定を行うフレーム同期部４１８に渡され、その結果受信データ４２４が得られる。
【００５５】
すなわち、位相誤差検出部６０５で求められる位相誤差６０４、及び、位相誤差累積・平均化・補正量演算部６０３で求められる位相誤差補正量６０２は、それぞれ（数３）、（数４）によって求めることができる。
【００５６】
【数３】

【００５７】
【数４】

【００５８】
求められた位相誤差補正量６０２を、位相検波部４１４の出力である受信シンボルデータ４１５に加えることで、受信シンボルデータ４１５の位相を補正する。
【００５９】
本実施の形態のダイバーシティ回路では、前記の自動周波数制御部４１６で求められる位相誤差６０４を、ブランチ選択に用いる位相誤差情報としてそのまま用いることで構成できる。すなわち、自動周波数制御部４１６で求められる位相誤差６０４を、ダイバーシティ用に設けた位相誤差累積部８０２においてあらかじめ定めた受信シンボルデータ分累積し、その位相誤差累積値８０２を、ダイバーシティ部８０４へ渡すように構成する。
【００６０】
すなわち、自動周波数制御部４１６で求められる位相誤差６０４、及び、位相誤差累積部８０２で求められる位相誤差累積値８０４は、それぞれ、（数３）、（数５）によって求めることができる。
【００６１】
【数５】

【００６２】
なお、位相誤差を累積するシンボル数や、累積回路の構成方法によっては、位相誤差累積部８０２を、自動周波数制御部４１６とダイバーシティ部８０４とで共有するよう構成しても良い。
【００６３】
次に、位相誤差累積部８０２で求めた位相誤差累積値８０３を用いて、ブランチ選択を行うダイバーシティ部８０４について図７を用いて説明する。
【００６４】
受信信号レベル比較部７０２は、全ブランチの受信信号レベル４２１ａ〜４２１ｎを比較し、最も受信信号レベルの大きいブランチを検出する。続いて、最も受信信号レベルの大きいブランチと、受信信号レベルの差が小さいブランチが存在するかどうかを調べる。ここで受信信号レベルの差が小さいかどうかの判定は、受信信号レベルの差が、あらかじめ定めた閾値より大きい場合は受信信号レベル差が大きいと判定し、あらかじめ定めた閾値より小さい場合は受信信号レベル差が小さいと判定することにより行う。
【００６５】
前記の受信信号レベル比較の結果、最も受信信号レベルの大きいブランチと、受信信号レベルの差が小さいブランチが存在しない場合は、位相誤差累積値比較部７０５に対し、位相誤差累積値比較が不要であること、及び、最も受信信号レベルの大きいブランチの番号を、受信レベル比較結果通知信号７０３にて通知する。一方、最も受信信号レベルの大きいブランチと、受信信号レベルの差が小さいブランチが存在する場合は、位相誤差累積値比較部７０５に対し、位相誤差累積値比較が必要であること、及び、最も受信信号レベルの大きいブランチと受信信号レベルの差が小さいブランチのリストを、受信レベル比較結果通知信号７０３にて通知する。
【００６６】
位相誤差累積値比較部７０５は、受信レベル比較結果通知信号７０３より、位相誤差累積値比較が不要であると通知された場合は、最も受信信号レベルの大きいブランチが最も受信品質が良いと判定し、最も受信信号レベルの大きいブランチの選択を指示するブランチ選択信号７０６を出力する。一方、受信レベル比較結果通知信号７０３より、位相誤差累積値比較が必要であると通知された場合は、前記の最も受信信号レベルの大きいブランチと受信信号レベルの差が小さいブランチのリストに示されたブランチの位相誤差累積値を、各ブランチから通知された位相誤差累積値８０３ａ〜８０３ｎを用いて比較する。
【００６７】
位相誤差累積知比較の結果、最も位相誤差累積値の小さい受信ブランチと、それ以外の前記リスト上の受信ブランチの位相誤差累積値との差があらかじめ定められた閾値より大きい場合は、最も位相誤差累積値の小さいブランチが最も受信品質が良いと判定して、位相誤差累積値が最も小さいブランチの選択を指示するブランチ選択信号７０６を出力する。
【００６８】
一方、位相誤差累積値比較の結果、最も位相誤差累積値の小さい受信ブランチと、それ以外の前記リスト上の受信ブランチの位相誤差累積値との差があらかじめ定められた閾値より小さい場合は、位相誤差累積値の差は同等と判断し、前記リスト上の受信ブランチの中で最も受信信号レベルの大きいブランチが最も受信品質が良いと判定して、前記リスト上の受信ブランチの中で最も受信信号レベルの大きいブランチの選択を指示するブランチ選択信号７０６を出力する。
【００６９】
受信ブランチ選択部７０８は、ブランチ選択信号７０６により選択を指示されたブランチの受信データを、各ブランチからの受信データ４２４ａ〜４２４ｎの中から選択して、ダイバーシティ部８０４で選択した受信データ８０５として出力する。
【００７０】
次に、図１２にＣ／Ｎと位相誤差累積値の関係を示す。この図よりわかるように、受信信号の品質（Ｃ／Ｎ）が悪いときは、位相誤差累積値が大きくなるという関係があり、ブランチ判定に位相誤差累積値が有効に利用できることがわかる。
【００７１】
なお、以上の説明では、４相位相変調信号を用いた例で説明したが、８相位相変調システムなどの別の位相変調システムにおいても実施可能である。また、受信信号レベル４２１ａ、ｂは、受信信号レベル検出部４２２ａ、ｂにおいて、波形整形後の同相成分（Ｉ信号４１０ａ、ｂ）、または、波形整形後の直交成分（Ｑ信号４１１ａ、ｂ）のいずれを用いても、実施可能である。
【００７２】
更には、従来技術のように、受信信号レベルとしてＩ信号及びＱ信号２乗和の平方根を用いる場合など、受信信号レベル比較に利用できるものであれば、同様の構成で実施可能である。
【００７３】
以上説明したように、ダイバーシティ回路において、最も品質の良いブランチの受信データを選択する際に、直交検波後の同相成分（Ｉ信号）または直交成分（Ｑ信号）の絶対値の平均のみから求めた受信信号レベルと、受信シンボルデータ４１５の位相誤差累積値から選択するように構成したもので、ブランチ選択精度を更に高めることが可能となり、簡易な構成のダイバーシティ回路が得られる。
【００７４】
（実施の形態３）
図８に、本発明の実施の形態３における受信装置の構成を示すブロック図を示し、以下に説明する。これは、二つのブランチａ，ｂから構成される受信装置の例である。実施の形態３は、実施の形態２で述べた受信信号レベル及び位相誤差累積値を用いたブランチ選択手段に、さらにダイバーシティ部でフレーム同期判定結果をブランチ選択条件に加えた点が異なり、異なる点を中心に説明する。
【００７５】
本発明の実施の形態の骨子は、自動利得制御用に受信信号レベル検出部４２２ａ，ｂで生成された受信信号レベル４２１ａ、ｂは、ダイバーシティ部１００２に対しても入力され、自動周波数制御部４１６ａ、４１６ｂで生成された、受信シンボルデータ４１５ａ、ｂの位相誤差は、ダイバーシティ用の位相誤差累積部８０２ａ、ｂであらかじめ定められたシンボル数分累積され、位相誤差累積値８０３ａ、ｂとしてダイバーシティ部１００２に対して入力される。ダイバーシティ部１００２は、受信信号レベル４２１ａ、ｂ、位相誤差累積値８０３ａ、ｂ、及び、フレーム同期判定結果１００１ａ、ｂを用いて、後述のダイバーシティ手順により、最も受信品質が良いブランチを選択し、選択されたブランチからの受信データ１００３を出力するものである。
【００７６】
以下に、実施の形態２と異なるフレーム同期部４１８及びダイバーシティ部１００２を中心に説明する。
【００７７】
次に、フレーム同期部４１８のフレーム同期判定処理について説明する。
フレーム同期部４１８ａ、ｂは、受信シンボルデータ列と、フレーム同期用の既知のシンボルデータ列との相関を取ることで、受信シンボルデータ列からフレーム同期の検出を試みる。そして、前記相関が取れた場合は、フレーム同期確立が成功したと判定し、前記相関が取れなかった場合は、フレーム同期確立は不成功と判定する。この判定結果を示すフレーム同期判定結果１００１ａ、ｂは、ダイバーシティ部１００２に通知される。
【００７８】
さらに、フレーム同期部４１８ａ、ｂは、フレーム同期確立の成功、不成功を示すフレーム同期判定結果１００１ａ、ｂを、ダイバーシティ部１００２に通知する。
【００７９】
図９は、実施の形態２で述べた受信信号レベル及び位相誤差累積値を用いたブランチ選択に、さらにフレーム同期判定結果をブランチ選択条件に加えたダイバーシティ部１００２のブロック構成図を示したものである。
【００８０】
受信信号レベル比較部９０２は、まず、全ブランチのフレーム同期部４１８から通知されたフレーム同期判定結果１００１ａ〜１００１ｎを調べ、フレーム同期確立が不成功であったブランチの有無を確認する。
【００８１】
フレーム同期確立の成功、不成功の確認の結果、すべてのブランチにおいてフレーム同期確立が不成功であった場合は、受信信号レベル比較部９０２は全ブランチからの受信データに信頼性が無く、ブランチ選択処理の意味が無いと判断し、位相誤差累積値比較部９０６に対し、前回選択されたブランチの選択を保持するように、受信レベル比較結果通知信号９０３を用いて通知する。
【００８２】
一方、フレーム同期確立の成功、不成功の確認の結果、一部のブランチのみにおいてフレーム同期確立が不成功であった場合は、受信信号レベル比較部９０２はフレーム同期確立が不成功であったブランチからの受信データに信頼性が無いと判断し、フレーム同期確立が成功であったブランチのみを用いて受信信号レベル４２１ａ〜４２１ｎを比較し、最も受信信号レベルの大きいブランチを検出する。続いて、最も受信信号レベルの大きいブランチと、受信信号レベルの差が小さいブランチが存在するかどうかを調べる。ここで受信信号レベルの差が小さいかどうかの判定は、受信信号レベルの差が、あらかじめ定めた閾値より大きい場合は受信信号レベル差が大きいと判定し、あらかじめ定めた閾値より小さい場合は受信信号レベル差が小さいと判定することにより行う。
【００８３】
前記の受信信号レベル比較の結果、最も受信信号レベルの大きいブランチと、受信信号レベルの差が小さいブランチが存在しない場合は、位相誤差累積値比較部９０６に対し、位相誤差累積値比較が不要であること、及び、最も受信信号レベルの大きいブランチの番号を、受信レベル比較結果通知信号９０３にて通知する。一方、最も受信信号レベルの大きいブランチと、受信信号レベルの差が小さいブランチが存在する場合は、位相誤差累積値比較部９０６に対し、位相誤差累積値比較が必要であること、及び、最も受信信号レベルの大きいブランチと受信信号レベルの差が小さいブランチのリストを、受信レベル比較結果通知信号９０３にて通知する。
【００８４】
位相誤差累積値比較部９０６は、受信レベル比較結果通知信号９０３より、位相誤差累積値比較が不要であると通知された場合は、最も受信信号レベルの大きいブランチが最も受信品質が良いと判定し、最も受信信号レベルの大きいブランチの選択を指示するブランチ選択信号９０７を出力する。一方、受信レベル比較結果通知信号９０３より、位相誤差累積値比較が必要であると通知された場合は、前記の最も受信信号レベルの大きいブランチと受信信号レベルの差が小さいブランチのリストに示されたブランチの位相誤差累積値を、各ブランチから通知された位相誤差累積値８０３ａ〜８０３ｎを用いて比較する。位相誤差累積知比較の結果、最も位相誤差累積値の小さい受信ブランチと、それ以外の前記リスト上の受信ブランチの位相誤差累積値との差があらかじめ定められた閾値より大きい場合は、最も位相誤差累積値の小さいブランチが最も受信品質が良いと判定して、位相誤差累積値が最も小さいブランチの選択を指示するブランチ選択信号９０７を出力する。一方、位相誤差累積値比較の結果、最も位相誤差累積値の小さい受信ブランチと、それ以外の前記リスト上の受信ブランチの位相誤差累積値との差があらかじめ定められた閾値より小さい場合は、位相誤差累積値の差は同等と判断し、前記リスト上の受信ブランチの中で最も受信信号レベルの大きいブランチが最も受信品質が良いと判定して、前記リスト上の受信ブランチの中で最も受信信号レベルの大きいブランチの選択を指示するブランチ選択信号９０７を出力する。
【００８５】
受信ブランチ選択部９０９は、ブランチ選択信号９０７により選択を指示されたブランチの受信データを、各ブランチからの受信データ４２４ａ〜４２４ｎの中から選択して、ダイバーシティ部１００２で選択した受信データ１００３として出力する。
【００８６】
なお、ダイバーシティ部１００２の受信ブランチの選択は、フレーム同期判定結果１００１と受信信号レベル４２１との組合わせのみで判定してもよい。
【００８７】
以上説明したように、ダイバーシティ回路において、最も品質の良いブランチの受信データを選択する際に、フレーム同期判定結果と、直交検波後の同相成分（Ｉ信号）または直交成分（Ｑ信号）の絶対値の平均のみから求めた受信信号レベルと、受信シンボルデータ４１５の位相誤差累積値から選択するように構成したもので、ブランチ選択精度を更に高めることが可能となり、簡易な構成のダイバーシティ回路が得られる。
【００８８】
（実施の形態４）
図１０は、本発明の実施の形態４における受信装置のブロック構成図を示すもので、実施の形態１とは復調処理と受信レベル検出処理の処理時間の差を吸収し、ブランチ選択精度を高めるために、復調処理系と受信レベル検出処理系の一方に遅延部を挿入した点が異なり、異なる点を中心に説明する。
【００８９】
本発明の背景について説明する。実施の形態１で述べた受信装置（図１）において、チャネルフィルタ部４０９ａ、ｂが出力した波形整形後の同相成分（Ｉ信号４１０ａ、ｂ）及び波形整形後の直交成分（Ｑ信号４１１ａ、ｂ）は、位相変換部４１２ａ、ｂからフレーム同期部４１８ａ、ｂまでの復調処理と、受信信号レベル検出部４２２ａ、ｂでの受信信号レベル検出処理の二つの処理に使用される。復調処理により得られた受信データ４２４ａ、ｂは、フレーム同期部４１８ａ、ｂより、ダイバーシティ部４２５に渡される。一方、受信レベル検出処理により得られた受信信号レベル４２１ａ、ｂも、ダイバーシティ部８０４に渡される。
【００９０】
これらの復調処理と受信レベル検出処理は、処理時間が同じとは限らないため、処理時間異なる場合、同じＩ信号４１０ａ、ｂ及びＱ信号４１１ａ、ｂより求められた受信データ４２４ａ、ｂと受信信号レベル４２１ａ、ｂは、ダイバーシティ部４２５に異なったタイミングで入力されることになり、受信データと受信信号レベルの時間相関が低くなってしまう。
【００９１】
その結果、特に短期間に受信信号レベル変動が生じた場合、ブランチ選択精度が低下する場合があり、これを防ぎブランチ選択精度を向上させることを目的としている。
【００９２】
図１０は、復調処理時間が、受信レベル検出処理時間より長い場合を想定し、実施の形態１で述べた受信信号レベル検出部およびダイバーシティ部を用いた受信装置において、受信信号レベル検出部４２２ａ、ｂからダイバーシティ部１１０３へ渡される受信信号レベル４２１ａ、ｂを、ダイバーシティ部１１０３の前段に配置した遅延部１１０１ａ、ｂにより遅延させることで、ブランチ判定に用いる情報のダイバーシティ部１１０３への入力タイミングを調整するように構成した受信装置のブロック図である。
【００９３】
遅延部１１０１ａ、ｂは、復調処理と受信レベル検出処理の処理時間の差に相当する遅延器を備えており、これによりダイバーシティ部１１０３に入力される受信データ４２４ａ、ｂと受信信号レベル１１０２ａ、ｂの時間相関は高くなり、ブランチ選択精度を向上させることができる。
【００９４】
また、実施の形態２の図４で示したような位相誤差累積値をブランチ選択条件に含めたダイバーシティ手段や、実施の形態３の図８で示したような位相誤差累積値及びフレーム同期判定結果をブランチ選択条件に含めたダイバーシティ手段においても、位相誤差累積値、フレーム同期判定結果、受信信号レベル及び受信データのダイバーシティ部への入力前に、それぞれの信号を得るのに必要な処理時間の差を吸収する遅延量の遅延器の挿入することにより、各信号間の時間相関を高めることができ、ブランチ選択精度を向上させることができる。
【００９５】
【発明の効果】
以上のように本発明によれば、無線通信システムの受信装置において、受信信号レベルの検出を、直交検波後の同相成分（Ｉ信号）または直交成分（Ｑ信号）の絶対値の平均のみから求めように構成することで、ダイバーシティ回路を簡易な構成で実現することができ、受信装置の小型化が図れる。
【００９６】
さらに、位相検波後の位相情報を元に容易に得られる位相誤差の累積値、フレーム同期確立の成功、不成功の結果をブランチ選択条件に加えることで、前記ダイバーシティ回路のブランチ選択精度を更に向上させることができる。
【００９７】
また、受信データと、ブランチ選択の判断材料である前記の受信信号レベル、位相誤差累積値、及び、フレーム同期確立結果の時間相関を調整してダイバーシティ回路へ入力することで、ブランチ選択精度の更なる改善が可能となる。
【図面の簡単な説明】
【図１】本発明の実施の形態１における受信装置のブロック構成図
【図２】本発明の実施の形態１による受信信号レベル検出回路の構成を示すブロック図
【図３】本発明の実施の形態１によるダイバーシティ回路の構成を示すブロック図
【図４】本発明の実施の形態２における受信装置のブロック構成図
【図５】４相位相変調信号の位相検波後の信号点配置を説明する図
【図６】本発明の実施の形態２による自動周波数制御部の構成を示すブロック図
【図７】本発明の実施の形態２によるダイバーシティ回路の構成を示すブロック図
【図８】本発明の実施の形態３における受信装置のブロック構成図
【図９】本発明の実施の形態３によるダイバーシティ回路の構成を示すブロック図
【図１０】本発明の実施の形態４における受信装置のブロック構成図
【図１１】従来の技術による受信信号レベル検出回路の構成を示すブロック図
【図１２】本発明の受信信号の品質Ｃ／Ｎと位相誤差累積値の関係を説明する図
【符号の説明】
２０２ 平均処理部
２０４ 受信信号レベル演算部
３０２ 受信信号レベル比較部
３０４ 受信ブランチ選択部
４０２ａ、ｂ ＩＦアンプ
４０４ａ、ｂ Ａ／Ｄ変換部
４０６ａ、ｂ 直交検波部
４０９ａ、ｂ チャネルフィルタ部
４１２ａ、ｂ 位相変換部
４１４ａ、ｂ 位相検波部
４１６ａ、ｂ 自動周波数制御部
４１８ａ、ｂ フレーム同期部
４１９ａ、ｂ 自動利得制御部
４２２ａ、ｂ 受信信号レベル検出部
４２５ ダイバーシティ部
４２７ａ、ｂ アンテナ
４２８ａ、ｂ ＲＦ部
５０５ 第１象現
５０６ 受信シンボルデータの信号点配置
５０７ 位相誤差
６０３ 位相誤差累積・平均化・補正量演算部
６０５ 位相誤差検出部
６０６ 補正部
７０２ 受信信号レベル比較部
７０５ 位相誤差累積値比較部
７０８ 受信ブランチ選択部
８０２ａ、ｂ 位相誤差累積部
８０４ ダイバーシティ部
９０２ 受信信号レベル比較部
９０６ 位相誤差累積値比較部
９０９ 受信ブランチ選択部
１００２ ダイバーシティ部
１１０１ａ、ｂ 遅延部
１１０３ ダイバーシティ部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a diversity receiving method and a diversity circuit for improving reception quality when receiving a digital phase modulation signal in a digital mobile communication system.
[0002]
[Prior art]
In a digital mobile communication environment, there is a problem of fading due to multipath, which is a characteristic of a wireless communication path, and the level fluctuation and phase rotation of a received signal caused by the problem are major factors in deterioration of reception quality. Therefore, fading countermeasures are an important issue when performing digital mobile communication. Conventionally, an automatic gain control method or a diversity method has been adopted as a countermeasure.
[0003]
Further, in a digital mobile communication environment, applications are diversifying year by year, and a device that performs small and simple control is often required.
[0004]
As a conventional diversity method, there is a method of comparing received signal levels and selecting a branch having a higher received signal level. One example of this method is shown in FIG.
[0005]
FIG. 11 shows a part of the configuration of the receiving device after the IF signal after frequency conversion of the received wireless signal. The level of the reception IF signal 101 is controlled by an IF amplifier 102 so as to approach a target level. The gain of the IF amplifier 102 is determined by the gain control signal 112 obtained by the automatic gain control unit 113. The IF amplifier output signal 103 is sampled by the A / D converter 104. The digital IF signal 105 obtained by sampling is subjected to quadrature detection by the quadrature detection unit 106, and an in-phase component (I signal 107) and a quadrature component (Q signal 108) are obtained.
[0006]
Further, the in-phase component (I signal 107) and the quadrature component (Q signal 108) are subjected to waveform shaping processing in the channel filter unit 109, and the in-phase component (I signal 110) after the waveform shaping and the quadrature component (Q signal) after the waveform shaping. 111) is obtained. The I signal 110 and the Q signal 111 are used for demodulation processing. The I signal 110 and the Q signal 111 are also input to the reception signal level detection unit 118, and the reception signal level calculation unit 117 causes the square root of the sum of squares of the I signal 110 and the Q signal 111 (: instantaneous reception signal level 116) is required.
[0007]
The instantaneous received signal level 116 is averaged by the averaging section 115 for a predetermined amount of data. That is, the received signal level obtained by the received signal level detection unit 118 is obtained by (Equation 1).
[0008]
(Equation 1)

[0009]
Received signal level 114 is input to diversity section and automatic gain control section 113. The diversity unit compares the reception signal levels from the reception branches, determines that the reception data from the branch with the highest reception signal level has the highest reliability, and selects the reception data from that branch (for example, see Patent Reference 1).
[0010]
[Patent Document 1]
JP 06-90227 A
[0011]
[Problems to be solved by the invention]
As in the above-described prior art example, a method of using the square root of the sum of squares of the I signal and the Q signal is often used as a method of obtaining the reception signal level. However, the operation for obtaining the square or the square root has a problem that the circuit becomes complicated and the scale becomes large.
[0012]
Further, in the conventional diversity system, a method of selecting a branch from various combinations of information, such as using an error rate obtained from demodulated data as well as a received signal level, is used. However, if the method of detecting the received signal level is simplified to reduce the size of the circuit, the accuracy of the comparison of the received signal quality in the diversity circuit is degraded. Then, there is a problem that a circuit for realizing it becomes large.
[0013]
Further, in order to reduce the size of the receiving circuit to an LSI, it is required that each processing unit be realized with a configuration as simple as possible.
[0014]
Therefore, the present invention improves the reception quality with a simple configuration by simplifying the reception signal level detection method and adding a phase error value easily obtained at the time of phase modulation signal demodulation processing to the branch determination condition in a wireless communication system. It is an object of the present invention to provide a diversity circuit that can realize the above.
[0015]
[Means for Solving the Problems]
In order to solve this problem, the present invention is configured to detect a received signal level only from an average of absolute values of an in-phase component (I signal) or a quadrature component (Q signal) after quadrature detection. .
[0016]
Further, the present invention accumulates a phase error value easily obtained at the time of a phase modulation signal demodulation process by a predetermined symbol data, and further includes a phase error accumulation condition in a branch determination condition when a difference between received signal levels among a plurality of branches is small. It is configured to use a value.
[0017]
As a result, the size of the received signal level detection circuit can be reduced, and the branch selection accuracy can be increased without adding a particularly complicated circuit, and a diversity circuit having a simple configuration can be obtained.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the first aspect of the present invention, an average value of absolute values of either an in-phase component or a quadrature component obtained by performing quadrature detection on a received signal is used as a received signal level, and comparison is performed between a plurality of reception branches. , Selecting the received data from the receiving branch having the highest received signal level. By selecting the received data from the receiving branch having the highest received signal level, the branch selection accuracy can be improved, and the received signal level can be improved. Can be realized with a simple configuration.
[0019]
According to a second aspect of the present invention, an average value of absolute values of either an in-phase component or a quadrature component obtained by quadrature detection of a received signal is obtained as a received signal level, and a phase obtained by demodulating a phase-modulated signal is obtained. Using the data, a phase error from an ideal phase of the phase data is calculated for a predetermined symbol data to obtain a phase error accumulated value, and received data from a receiving branch is obtained from the received signal level and the phase error accumulated value. By selecting the reception data from the reception branch from the reception signal level and the accumulated phase error value, the branch selection accuracy is improved, and the reception signal level detection circuit is realized with a simple configuration. It has the effect of being able to.
[0020]
According to a third aspect of the present invention, in the diversity receiving method according to the first or second aspect, the reception data is selected by selecting the reception signal level of the reception branch having the highest reception signal level and the reception signal level of the other reception branches. If the difference from the received signal is larger than a predetermined threshold, the received signal from the receiving branch with the highest received signal level is selected. By adding a difference from the received signal level of the branch to the selection condition and performing the branch selection in a situation where the difference is a significant difference in comparing the received signal quality, the branch selection accuracy is improved and the received signal is improved. This has the effect that the level detection circuit can be realized with a simple configuration.
[0021]
According to a fourth aspect of the present invention, in the diversity receiving method according to the second aspect, the selection of the received data is performed based on the reception signal level of the reception branch having the highest reception signal level and the reception signal level of the other reception branches. When the difference is smaller than a predetermined threshold value, the reception signal from the reception branch with the smallest phase error accumulation value is selected, and the reception signal with the highest reception signal level and the other reception branches are selected. In a situation where this difference is not a significant difference in comparing the received signal quality, the branch selection is performed by switching the branch selection condition to the accumulated phase error value. And operation of improving the branch selection accuracy and realizing a reception signal level detection circuit with a simple configuration. A.
[0022]
According to a fifth aspect of the present invention, in the diversity receiving method according to the second aspect, the selection of the reception data is such that a difference between the phase difference accumulated value between the reception branch having the smallest phase error accumulated value and the other reception branches is determined. When there is a reception branch smaller than a predetermined threshold, the reception branch having the largest reception signal level among the reception branches is selected, and the reception branch having the smallest phase error accumulated value is selected. And adding the difference of the phase error accumulated value with the other reception branches to the selection condition, and when the difference is not a significant difference in comparing the reception signal quality, the branch selection condition is switched to the reception signal level. By performing the branch selection, the branch selection accuracy can be improved, and the reception signal level detection circuit can be realized with a simple configuration. It has the effect that it is possible.
[0023]
According to a sixth aspect of the present invention, in the diversity receiving method according to any one of the first to fifth aspects, as a result of performing the frame synchronization process using the received signal, whether the frame synchronization is successfully established or not succeeded. From the frame synchronization determination result indicating whether or not frame synchronization has been successfully established, selection is made from reception branch candidates, and reception branches determined to be out of frame synchronization are excluded from reception branch selection candidates. This has the effect that the branch selection accuracy can be improved.
[0024]
The invention according to claim 7, wherein a reception signal level detecting means for setting a reception signal level to an average value of absolute values of either an in-phase component or a quadrature component obtained by quadrature detection of the reception signal; A receiving branch selecting unit that compares received signal levels obtained by the detecting unit among a plurality of receiving branches and selects received data from a receiving branch having the largest received signal level; By selecting the reception data from the reception branch, the branch selection accuracy can be improved, and the reception signal level detection circuit can be realized with a simple configuration.
[0025]
The invention according to claim 8 is a receiving signal level detecting means for setting a receiving signal level to an average value of absolute values of either an in-phase component or a quadrature component obtained by performing quadrature detection on a receiving signal; Phase error detecting means for detecting a phase error from an ideal phase of the phase data using phase data obtained by demodulation, and a phase for obtaining a phase error accumulated value obtained by accumulating the phase error by predetermined symbol data Error accumulation means, and reception branch selection means for selecting reception data from a reception branch from a reception signal level obtained by the reception signal level detection means and a phase error accumulation value obtained by the phase error accumulation means. By selecting received data from the receiving branch from the received signal level and the accumulated phase error value, the branch selection accuracy can be improved. With improved, an effect that the detection circuit of the reception signal level can be achieved with a simple configuration.
[0026]
According to a ninth aspect of the present invention, in the diversity circuit according to the seventh aspect, the reception branch selecting means is configured to determine a difference between a reception signal level of the reception branch having the highest reception signal level and a reception signal level of the other reception branches. Is larger than a predetermined threshold value, the reception signal from the reception branch with the highest reception signal level is selected, and reception of the reception signal with the highest reception signal level and reception of other reception branches is performed. By adding a difference from the signal level to the selection condition and performing branch selection in a situation where the difference is a significant difference in comparing the received signal quality, the branch selection accuracy is improved and the received signal level is detected. This has the effect that the circuit can be realized with a simple configuration.
[0027]
According to a tenth aspect of the present invention, in the diversity circuit according to the eighth aspect, the reception branch selecting means is configured to determine a difference between a reception signal level of the reception branch having the highest reception signal level and a reception signal level of the other reception branches. Is smaller than a predetermined threshold value, the reception signal from the reception branch having the smallest phase error accumulation value is selected, and the reception signal having the highest reception signal level and the reception signals of the other reception branches are selected. By adding the difference with the received signal level to the selection condition, in a situation where the difference is not a significant difference in comparing the received signal quality, the branch selection is performed by switching the branch selection condition to the accumulated phase error value. As a result, it is possible to improve the branch selection accuracy and to realize a reception signal level detection circuit with a simple configuration. It has the effect of that.
[0028]
According to an eleventh aspect of the present invention, in the diversity circuit according to the eighth aspect, the receiving branch selecting means determines in advance that the difference between the phase error cumulative values of the receiving branch having the smallest phase error cumulative value and the other receiving branches is the same. When there is a reception branch smaller than the predetermined threshold, the reception branch having the highest reception signal level among the reception branches is characterized by selecting the reception branch having the smallest phase error accumulated value. In addition, when adding the difference of the accumulated phase error with the other reception branches to the selection condition and comparing the received signal quality, if the difference of the accumulated phase error between the branches is not a significant difference, the branch selection condition Is switched to the reception signal level to perform branch selection, thereby improving branch selection accuracy and increasing the reception signal level. Has an effect of the detection circuit can be realized with a simple configuration.
[0029]
According to a twelfth aspect of the present invention, in the diversity circuit according to any one of the seventh to eleventh aspects, the frame synchronization processing is further performed by using the received signal. A frame synchronization determination unit that outputs a frame synchronization determination result indicating any one of them, and based on the frame synchronization determination result obtained by the frame synchronization determination unit, selecting from reception branch candidates with established frame synchronization. Therefore, by excluding a reception branch determined to be out of frame synchronization from reception branch selection candidates, the branch selection accuracy can be improved.
[0030]
According to a thirteenth aspect of the present invention, in the diversity circuit according to any one of the eighth to twelfth aspects, a received signal level and a phase error accumulated value obtained based on the same received signal or a received signal within a predetermined time difference. , Frame synchronization determination result, and timing adjustment means for adjusting the timing so that the received data is input to the diversity circuit. The difference in processing time required to obtain each signal By inserting a delay unit having a delay amount that absorbs the signal, it is possible to enhance the time correlation between the signals, thereby improving the branch selection accuracy.
[0031]
According to a fourteenth aspect of the present invention, there is provided a receiving apparatus for receiving reception data from the diversity circuit according to any one of the seventh to thirteenth aspects, and a highly reliable receiving apparatus can be realized. It has the action of:
[0032]
According to a fifteenth aspect of the present invention, there is provided a receiving apparatus according to the fourteenth aspect, and a transmitting apparatus for transmitting a phase-modulated data including frame synchronization data and transmitting the data. It has an effect that a high communication device can be realized.
[0033]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0034]
(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a receiving apparatus using a diversity circuit according to Embodiment 1 of the present invention. This is an example of a receiving device including two branches a and b.
[0035]
In FIG. 1, reference numerals 400a and 400b denote branches a and b for generating reception signal levels 421a and 421b obtained from the reception IF signals 401a and 401b and demodulated reception data 424a and 424 obtained from the frame synchronization units 418a and 418b, respectively. And 425, a diversity unit for selecting a branch using the received signal level in each branch and the received data after demodulation. Each branch includes an antenna 427, an RF unit 428, an IF amplifier 402, an A / D conversion unit 404, a quadrature detection unit 406, a channel filter unit 409, a reception signal level detection unit 422, an automatic gain control unit 419, and a demodulation processing unit. It comprises a phase converter 412, a phase detector 414, an automatic frequency controller 416, and a frame synchronizer 418.
[0036]
The operation of the receiving device configured as described above will be described below.
[0037]
The levels of the reception IF signals 401a and 401b are controlled by the IF amplifiers 402a and 402b so as to approach the target level. The gains of the IF amplifiers 402a and 402b are determined by the gain control signals 420a and 420b obtained by the automatic gain controllers 419a and 419b. The IF amplifier output signals 403a and 403b are sampled by A / D converters 404a and 404b. Digital IF signals 405a and 405b obtained by sampling are subjected to quadrature detection by quadrature detectors 406a and 406b to obtain in-phase components (I signals 407a and b) and quadrature components (Q signals 408a and 408b).
[0038]
Further, the in-phase components (I signals 407a and 407b) and the quadrature components (Q signals 408a and 408b) are subjected to waveform shaping processing in channel filter sections 409a and 409b. The shaped quadrature components (Q signals 411a and 411b) are obtained. The I signals 410a, b and the Q signals 411a, b are converted into phase data 413a, b in phase converters 412a, b. The phase detectors 414a and 414b perform detection using the phase data 413a and 413b, and receive symbol data 415a and 415b are obtained. The automatic frequency control units 416a and 416b detect a phase error from the phase information of the received symbol data, and accumulate and average the phase error by a predetermined symbol data to obtain a phase error correction amount. The received symbol data is brought closer to the phase of the ideal signal point. The received symbol data 417a and 417b whose phase errors have been corrected are passed to frame synchronization units 418a and 418b for performing frame synchronization and bit determination, and as a result, received data 424a and 424b are obtained.
[0039]
On the other hand, either the in-phase component (I signal) after waveform shaping obtained from the reception IF signals 401a and 401b or the quadrature component (Q signal) after waveform shaping is used as reception signal level determination data 423a and 423b to detect a reception signal level. The signals are input to the sections 422a and 422b to generate received signal levels 421a and 421b. The received signal levels 421a and 421b are used for input level control of the received IF signals 401a and 401b in the automatic gain control sections 419a and 419b, and are also input to the diversity section 425,
Diversity section 425 performs a diversity procedure described later using demodulated reception data 424a, b obtained from obtained reception signal levels 421a, b and frame synchronization sections 418a, b, to obtain a branch from the branch having the highest reception quality. The reception data 426 is selected.
[0040]
Next, the reception signal level detection units 422a and 422b will be described.
[0041]
FIG. 2 is a block diagram showing a detailed configuration from an IF amplifier 102 to an input to a demodulation processing unit (phase conversion units 412a and 412b to frame synchronization units 418a and 418b) in one branch in a receiver having a diversity circuit. It is.
[0042]
The level of the reception IF signal 401 is controlled by the IF amplifier 402 so as to approach the target level. The gain of IF amplifier 402 is determined by gain control signal 412 obtained by automatic gain control section 413. The IF amplifier output signal 403 is sampled by the A / D converter 404. The digital IF signal 405 obtained by sampling is subjected to quadrature detection by the quadrature detector 406, and an in-phase component (I signal 407) and a quadrature component (Q signal 408) are obtained. Further, the in-phase component (I signal 407) and the quadrature component (Q signal 408) are subjected to waveform shaping processing in the channel filter unit 409, and the in-phase component (I signal 410) after the waveform shaping and the quadrature component (Q signal) after the waveform shaping 411) is obtained.
[0043]
I signal 410 and Q signal 411 are used for demodulation processing. Further, I signal 410 is also input to reception signal level detection section 422. In the received signal level detector 422, the received signal level calculator 204 calculates the absolute value of the I signal 410 (the instantaneous received signal level 203). The average received signal level 203 is averaged by a predetermined data by the averaging unit 202, and is output to the diversity unit 425 and the automatic gain control unit 413 as the received signal level 421.
[0044]
That is, the reception signal level obtained by the reception signal level detection unit 422 can be obtained by (Equation 2).
[0045]
(Equation 2)

[0046]
In the above description, an example is described in which the in-phase component after waveform shaping (I signal 410) is used for detection of the reception signal level to reception signal level detection section 422, but the quadrature component (Q signal after waveform shaping) is used. 411) can also be used.
[0047]
Next, a diversity procedure of the diversity section 425 for performing branch selection using the reception signal levels 421a and 421b of each branch obtained as described above will be described. FIG. 3 is a block diagram showing a configuration of the diversity unit 425 for selecting a branch using the received signal level in each branch and the received data after demodulation.
[0048]
The received signal level comparing section 302 compares the received signal levels 421a to 421n of all branches (branches a to n), determines that the branch having the highest received signal level has the best reception quality, and indicates the branch indicating that branch. The selection signal 303 is output. The reception branch selection unit 304 outputs, as reception data 426 selected by the diversity unit 425, reception data from the branch indicated by the branch selection signal 303 among the reception data 4241 to 424n passed from each branch.
[0049]
As described above, in the diversity circuit, when selecting the reception data of the branch having the highest quality, the detection of the reception signal level is performed by detecting the absolute value of the in-phase component (I signal) or the quadrature component (Q signal) after quadrature detection. Since the configuration is such that the value is obtained only from the average of the values, the size of the received signal level detection circuit can be reduced, the branch selection accuracy can be increased, and a diversity circuit having a simple configuration can be obtained.
[0050]
(Embodiment 2)
FIG. 4 shows a block diagram of a receiving apparatus according to Embodiment 2 of the present invention, and will be described. As shown in FIG. 4, the second embodiment is different from the first embodiment in that phase error accumulators 803a and 803b for performing accumulation operation of phase error of received symbol data are provided. The difference is that the branch with the highest reception quality is selected using the received signal level and the accumulated phase error value, and the different points will be mainly described.
[0051]
The gist of the present invention is that the received signal levels 421a and 421b generated by the received signal level detectors 422a and 422b for automatic gain control are also input to the diversity unit 804, and the automatic frequency controller 416a is used. , B generated by the received symbol data 415 a, b are accumulated by a predetermined number of symbols in the diversity phase error accumulators 802 a, b to obtain phase error accumulated values 803 a, 803 b. Input to diversity section 804. Diversity section 804 selects the branch having the best reception quality by the above-described diversity procedure using reception signal levels 421a and 421b and accumulated phase errors 803a and 803b, and receives data 805 from the selected branch. Is output.
[0052]
Next, FIG. 6 shows an example of a block configuration diagram of the automatic frequency control units 416a and 416b and the phase error accumulation unit 802, which will be described below. In general, an automatic frequency control unit is mounted on a receiving device in order to correct a carrier frequency error used between a transmitting and receiving device. The carrier frequency error correction by the automatic frequency control unit uses a phase error described below. It can be carried out.
[0053]
FIG. 5 shows an example of the signal point arrangement after phase detection of the received four-phase modulation signal. Four possible ideal signal point arrangements are indicated by ◎ in 501, 502, 503 and 504. ing. Here, the signal point arrangement of the received symbol data is 506 (●). In the case of four-phase modulation, if the phase of the received symbol data is smaller than ± π / 4 from the phase of the ideal signal point, demodulation can be performed correctly. Therefore, as a result of transmitting the symbol data of the signal point constellation 501, if the phase error 507 with respect to the ideal signal point constellation 501 is smaller than ± π / 4 as in the case of the received symbol data 506 (●) (the first quadrant) 505), it can be determined that the symbol data corresponding to the ideal signal point arrangement 501 has been transmitted.
[0054]
The I signal 410 and Q signal 411 that have undergone quadrature detection and waveform shaping are converted into phase data 413 by a phase converter 412. The phase detector 414 performs detection using the phase data 413 to obtain received symbol data 415. The automatic frequency control unit 416 detects the phase error 604 from the ideal signal point in the phase error detection unit 605 from the phase information of the received symbol data 415 as described above, and calculates the phase error accumulation / averaging / correction amount. The section 603 accumulates and averages the phase error 604 by a predetermined amount of symbol data, and obtains a phase error correction amount 602 for bringing the received symbol data closer to the phase of an ideal signal point. The correction unit 606 corrects the received symbol data 415 output from the phase detection unit 414 with the obtained phase error correction amount 602. The received symbol data 601 whose phase error has been corrected is passed to a frame synchronization section 418 that performs frame synchronization and bit determination, and as a result, received data 424 is obtained.
[0055]
That is, the phase error 604 obtained by the phase error detection unit 605 and the phase error correction amount 602 obtained by the phase error accumulation / averaging / correction amount calculation unit 603 are obtained by (Equation 3) and (Equation 4), respectively. be able to.
[0056]
[Equation 3]

[0057]
(Equation 4)

[0058]
The phase of the received symbol data 415 is corrected by adding the obtained phase error correction amount 602 to the received symbol data 415 output from the phase detector 414.
[0059]
The diversity circuit according to the present embodiment can be configured by directly using the phase error 604 obtained by the automatic frequency control unit 416 as phase error information used for branch selection. That is, the phase error 604 obtained by the automatic frequency control unit 416 is accumulated by the predetermined received symbol data in the phase error accumulation unit 802 provided for diversity, and the accumulated phase error value 802 is passed to the diversity unit 804. To be configured.
[0060]
That is, the phase error 604 obtained by the automatic frequency control unit 416 and the phase error accumulated value 804 obtained by the phase error accumulation unit 802 can be obtained by (Equation 3) and (Equation 5), respectively.
[0061]
(Equation 5)

[0062]
Note that the phase error accumulator 802 may be shared by the automatic frequency controller 416 and the diversity unit 804 depending on the number of symbols for accumulating the phase error and the configuration method of the accumulator circuit.
[0063]
Next, a diversity section 804 that performs branch selection using the phase error accumulation value 803 obtained by the phase error accumulation section 802 will be described with reference to FIG.
[0064]
The reception signal level comparison unit 702 compares the reception signal levels 421a to 421n of all branches and detects the branch having the highest reception signal level. Then, it is checked whether there is a branch having the highest received signal level and a branch having a small difference between the received signal levels. Here, it is determined whether the difference between the received signal levels is small. If the difference between the received signal levels is larger than a predetermined threshold, the received signal level difference is determined to be large. This is performed by determining that the level difference is small.
[0065]
As a result of the received signal level comparison, when there is no branch having the largest received signal level and a branch having the small difference between the received signal levels, the phase error accumulated value comparison unit 705 does not need to perform the phase error accumulated value comparison. The presence and the number of the branch having the highest received signal level are notified by the reception level comparison result notification signal 703. On the other hand, when there is a branch having the largest received signal level and a branch having the smallest difference between the received signal levels, the phase error accumulated value comparison unit 705 needs to compare the phase error accumulated values, and A list of branches having a large signal level and a branch having a small difference between the received signal levels is notified by a reception level comparison result notification signal 703.
[0066]
When notified by the reception level comparison result notification signal 703 that the phase error accumulation value comparison is unnecessary, the phase error accumulated value comparison unit 705 determines that the branch having the highest received signal level has the best reception quality. , A branch selection signal 706 instructing selection of a branch having the highest received signal level. On the other hand, if it is notified from the reception level comparison result notification signal 703 that the comparison of the accumulated phase error values is necessary, it is indicated in the list of the branch having the largest reception signal level and the branch having the smallest difference between the reception signal levels. Then, the accumulated phase error values of the obtained branches are compared using the accumulated phase error values 803a to 803n notified from each branch.
[0067]
As a result of the phase error accumulation knowledge comparison, when the difference between the reception branch having the smallest phase error accumulation value and the phase error accumulation values of the other reception branches on the list is larger than a predetermined threshold value, It determines that the branch with the smallest cumulative value has the best reception quality, and outputs a branch selection signal 706 instructing selection of the branch with the smallest phase error cumulative value.
[0068]
On the other hand, if the result of the phase error accumulated value comparison indicates that the difference between the reception branch having the smallest phase error accumulated value and the phase error accumulated values of the other reception branches on the list is smaller than a predetermined threshold value, The difference between the accumulated error values is determined to be the same, the branch having the highest received signal level among the reception branches on the list is determined to have the best reception quality, and the reception signal is determined to be the best among the reception branches on the list. A branch selection signal 706 instructing selection of a branch having a higher level is output.
[0069]
The reception branch selection unit 708 selects the reception data of the branch designated to be selected by the branch selection signal 706 from the reception data 424a to 424n from each branch, and outputs it as the reception data 805 selected by the diversity unit 804. I do.
[0070]
Next, FIG. 12 shows the relationship between C / N and the accumulated phase error value. As can be seen from the figure, when the quality (C / N) of the received signal is poor, there is a relationship that the accumulated phase error increases, and it can be seen that the accumulated phase error can be effectively used for branch determination.
[0071]
In the above description, an example using a four-phase modulation signal has been described. However, the present invention can be implemented in another phase modulation system such as an eight-phase modulation system. The received signal levels 421a and 421b are converted by the received signal level detectors 422a and b into the in-phase components (I signals 410a and b) after waveform shaping or the quadrature components (Q signals 411a and b) after waveform shaping. Either of them can be used.
[0072]
Furthermore, a similar configuration can be used as long as it can be used for comparing received signal levels, such as in the case of using the square root of the sum of squares of the I signal and the Q signal as the received signal level as in the prior art.
[0073]
As described above, in the diversity circuit, when selecting the reception data of the branch having the highest quality, the reception data is obtained only from the average of the absolute values of the in-phase component (I signal) or the quadrature component (Q signal) after quadrature detection. Since the configuration is such that the selection is made from the received signal level and the accumulated phase error value of the received symbol data 415, the branch selection accuracy can be further increased, and a diversity circuit having a simple configuration can be obtained.
[0074]
(Embodiment 3)
FIG. 8 is a block diagram illustrating a configuration of a receiving apparatus according to Embodiment 3 of the present invention, and will be described below. This is an example of a receiving device including two branches a and b. The third embodiment is different from the branch selecting means using the received signal level and the accumulated phase error value described in the second embodiment in that a diversity unit adds a frame synchronization determination result to a branch selection condition. This will be mainly described.
[0075]
The gist of the embodiment of the present invention is that the received signal levels 421a and 421b generated by the received signal level detectors 422a and 422b for automatic gain control are also input to the diversity unit 1002 and the automatic frequency controller 416a. , 416b, the phase errors of the received symbol data 415a, b are accumulated by a predetermined number of symbols in diversity phase error accumulators 802a, 802b. Is entered for Diversity section 1002 selects a branch having the best reception quality by a diversity procedure described later using received signal levels 421a and 421b, accumulated phase error values 803a and 803b, and frame synchronization determination results 1001a and 100b. It outputs the received data 1003 from the selected branch.
[0076]
The following mainly describes the frame synchronization section 418 and the diversity section 1002 different from the second embodiment.
[0077]
Next, the frame synchronization determination process of the frame synchronization unit 418 will be described.
The frame synchronization units 418a and 418b attempt to detect frame synchronization from the received symbol data sequence by correlating the received symbol data sequence with a known symbol data sequence for frame synchronization. When the correlation is obtained, it is determined that the frame synchronization has been successfully established. When the correlation is not obtained, it is determined that the frame synchronization has not been successfully established. The frame synchronization determination results 1001 a and 1001 b indicating this determination result are notified to the diversity unit 1002.
[0078]
Further, the frame synchronization units 418a and 418b notify the diversity unit 1002 of frame synchronization determination results 1001a and 1001b indicating success or failure of establishment of frame synchronization.
[0079]
FIG. 9 is a block diagram of a diversity unit 1002 in which a frame synchronization determination result is added to a branch selection condition in addition to the branch selection using the received signal level and the accumulated phase error value described in the second embodiment. is there.
[0080]
First, the received signal level comparison unit 902 checks the frame synchronization determination results 1001a to 1001n notified from the frame synchronization units 418 of all the branches, and checks whether there is any branch whose frame synchronization has not been successfully established.
[0081]
If the frame synchronization establishment is unsuccessful in all branches as a result of confirming the success or failure of the frame synchronization establishment, the received signal level comparing unit 902 has no reliability in the data received from all the branches, and It is determined that the processing is meaningless, and the phase error accumulated value comparison unit 906 is notified using the reception level comparison result notification signal 903 so as to retain the selection of the previously selected branch.
[0082]
On the other hand, if the frame synchronization establishment is unsuccessful in only some of the branches as a result of confirming the success or unsuccess of the frame synchronization establishment, the reception signal level comparing unit 902 determines the branch in which the frame synchronization establishment was unsuccessful. It is determined that there is no reliability in the received data from, and the received signal levels 421a to 421n are compared using only the branch for which the frame synchronization has been successfully established, and the branch having the highest received signal level is detected. Then, it is checked whether there is a branch having the highest received signal level and a branch having a small difference between the received signal levels. Here, it is determined whether the difference between the received signal levels is small. If the difference between the received signal levels is larger than a predetermined threshold, the received signal level difference is determined to be large. This is performed by determining that the level difference is small.
[0083]
As a result of the received signal level comparison, when there is no branch having the largest received signal level and a branch having the small difference between the received signal levels, the phase error cumulative value comparison unit 906 does not need to perform the phase error cumulative value comparison. The presence and the number of the branch having the highest received signal level are notified by the received level comparison result notification signal 903. On the other hand, if there is a branch having the largest received signal level and a branch having the smallest difference between the received signal levels, the phase error accumulated value comparison section 906 needs to perform the phase error accumulated value comparison, and A list of branches having a large signal level and a branch having a small difference between the received signal levels is notified by a reception level comparison result notification signal 903.
[0084]
When notified by the reception level comparison result notification signal 903 that the phase error accumulation value comparison is unnecessary, the phase error accumulated value comparison unit 906 determines that the branch having the highest received signal level has the best reception quality. , A branch selection signal 907 instructing selection of a branch having the highest received signal level. On the other hand, if it is notified from the reception level comparison result notification signal 903 that the comparison of the accumulated phase error values is necessary, it is indicated in the list of the branch having the largest reception signal level and the branch having the smallest difference between the reception signal levels. Then, the accumulated phase error values of the obtained branches are compared using the accumulated phase error values 803a to 803n notified from each branch. As a result of the phase error accumulation knowledge comparison, when the difference between the reception branch having the smallest phase error accumulation value and the phase error accumulation values of the other reception branches on the list is larger than a predetermined threshold value, It determines that the branch with the smallest accumulated value has the best reception quality, and outputs a branch selection signal 907 instructing selection of the branch with the smallest phase error accumulated value. On the other hand, if the result of the phase error accumulated value comparison indicates that the difference between the reception branch having the smallest phase error accumulated value and the phase error accumulated values of the other reception branches on the list is smaller than a predetermined threshold value, The difference between the accumulated error values is determined to be the same, the branch having the highest received signal level among the reception branches on the list is determined to have the best reception quality, and the reception signal is determined to be the best among the reception branches on the list. A branch selection signal 907 instructing selection of a branch having a higher level is output.
[0085]
The reception branch selection unit 909 selects the reception data of the branch designated to be selected by the branch selection signal 907 from the reception data 424a to 424n from each branch, and outputs it as the reception data 1003 selected by the diversity unit 1002. I do.
[0086]
Note that the selection of the receiving branch of diversity section 1002 may be determined only by a combination of frame synchronization determination result 1001 and received signal level 421.
[0087]
As described above, in the diversity circuit, when selecting the reception data of the highest quality branch, the frame synchronization determination result and the absolute value of the in-phase component (I signal) or the quadrature component (Q signal) after quadrature detection are selected. Are selected from the received signal level obtained from only the average and the phase error accumulated value of the received symbol data 415, so that the branch selection accuracy can be further increased, and a diversity circuit having a simple configuration can be obtained. .
[0088]
(Embodiment 4)
FIG. 10 is a block diagram of a receiving apparatus according to Embodiment 4 of the present invention, which is different from Embodiment 1 in that a difference in processing time between demodulation processing and reception level detection processing is absorbed to improve branch selection accuracy. For this reason, the difference is that a delay unit is inserted in one of the demodulation processing system and the reception level detection processing system.
[0089]
The background of the present invention will be described. In the receiving apparatus (FIG. 1) described in the first embodiment, in-phase components (I signals 410a, b) after waveform shaping and quadrature components (Q signals 411a, b) after waveform shaping output by channel filter sections 409a, b. ) Are used for two processes: a demodulation process from the phase conversion units 412a and 412b to the frame synchronization units 418a and 418b, and a reception signal level detection process in the reception signal level detection units 422a and 422b. The received data 424a and 424b obtained by the demodulation process are passed from the frame synchronization units 418a and 418b to the diversity unit 425. On the other hand, received signal levels 421 a and 421 b obtained by the received level detection processing are also passed to diversity section 804.
[0090]
Since the demodulation process and the reception level detection process do not always have the same processing time, if the processing times are different, the reception data 424a, b obtained from the same I signal 410a, b and Q signal 411a, b and the reception signal The levels 421a and 421b are input to the diversity unit 425 at different timings, and the time correlation between the received data and the received signal level becomes low.
[0091]
As a result, especially when the received signal level fluctuates in a short period of time, the branch selection accuracy may be reduced, and the object is to improve the branch selection accuracy.
[0092]
FIG. 10 illustrates a case where the demodulation processing time is longer than the reception level detection processing time, and in the receiving apparatus using the reception signal level detection unit and the diversity unit described in Embodiment 1, reception signal level detection unit 422a, The input timing of information used for branch determination to the diversity unit 1103 is adjusted by delaying the reception signal levels 421a and 421b passed from b to the diversity unit 1103 by the delay units 1101a and 110b arranged before the diversity unit 1103. FIG. 3 is a block diagram of a receiving device configured to perform the above operation.
[0093]
Each of the delay units 1101a and 1101b includes a delay unit corresponding to the difference between the processing time of the demodulation processing and the processing time of the reception level detection processing, so that the reception data 424a and b input to the diversity unit 1103 and the reception signal levels 1102a and 1102b , The time correlation becomes higher, and the branch selection accuracy can be improved.
[0094]
Also, the diversity means including the phase error cumulative value as shown in FIG. 4 of the second embodiment in the branch selection condition, the phase error cumulative value and the frame synchronization determination result as shown in FIG. 8 of the third embodiment. Is included in the branch selection condition, the phase error accumulated value, the frame synchronization determination result, the received signal level, and the difference in processing time required to obtain each signal before inputting the received data to the diversity unit. By inserting a delay unit having a delay amount that absorbs the signal, the time correlation between the signals can be increased, and the branch selection accuracy can be improved.
[0095]
【The invention's effect】
As described above, according to the present invention, in the receiving apparatus of the wireless communication system, the detection of the received signal level is obtained only from the average of the absolute values of the in-phase component (I signal) or the quadrature component (Q signal) after quadrature detection. With such a configuration, the diversity circuit can be realized with a simple configuration, and the receiving device can be downsized.
[0096]
Furthermore, the branch selection accuracy of the diversity circuit is further improved by adding the accumulated value of the phase error easily obtained based on the phase information after the phase detection, the success or failure of the frame synchronization establishment to the branch selection condition. Can be done.
[0097]
Further, by adjusting the received data and the above-mentioned received signal level, phase error accumulated value, and time correlation of the frame synchronization establishment result, which are factors for determining branch selection, and inputting them to the diversity circuit, the accuracy of branch selection can be improved. Some improvements can be made.
[Brief description of the drawings]
FIG. 1 is a block diagram of a receiving apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a block diagram showing a configuration of a reception signal level detection circuit according to the first embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration of a diversity circuit according to the first embodiment of the present invention.
FIG. 4 is a block diagram of a receiving apparatus according to Embodiment 2 of the present invention.
FIG. 5 is a view for explaining signal point arrangement after phase detection of a four-phase modulation signal.
FIG. 6 is a block diagram illustrating a configuration of an automatic frequency control unit according to a second embodiment of the present invention.
FIG. 7 is a block diagram showing a configuration of a diversity circuit according to a second embodiment of the present invention.
FIG. 8 is a block diagram of a receiving apparatus according to a third embodiment of the present invention.
FIG. 9 is a block diagram showing a configuration of a diversity circuit according to a third embodiment of the present invention.
FIG. 10 is a block diagram of a receiving apparatus according to a fourth embodiment of the present invention.
FIG. 11 is a block diagram showing a configuration of a reception signal level detection circuit according to a conventional technique.
FIG. 12 is a view for explaining the relationship between the received signal quality C / N and the phase error accumulated value according to the present invention;
[Explanation of symbols]
202 Average processing unit
204 Received signal level calculator
302 Received signal level comparison unit
304 Receive branch selector
402a, b IF amplifier
404a, b A / D converter
406a, b Quadrature detector
409a, b Channel filter unit
412a, b Phase converter
414a, b Phase detector
416a, b Automatic frequency control unit
418a, b Frame synchronization unit
419a, b Automatic gain control unit
422a, b Received signal level detector
425 Diversity Department
427a, b antenna
428a, b RF unit
505 The first elephant
506 Signal point arrangement of received symbol data
507 Phase error
603 Phase error accumulation / averaging / correction amount calculation unit
605 Phase error detector
606 Correction unit
702 Received signal level comparison unit
705 Phase error accumulated value comparison unit
708 Receiving branch selector
802a, b Phase error accumulator
804 Diversity Department
902 Received signal level comparison unit
906 Phase error accumulated value comparison unit
909 Receiving branch selector
1002 Diversity Department
1101a, b delay unit
1103 Diversity Department

Claims (15)

The average value of the absolute values of either the in-phase component or the quadrature component obtained by quadrature detection of the received signal is used as the received signal level, compared between a plurality of receiving branches, and received from the receiving branch having the highest received signal level. A diversity receiving method comprising selecting data. The average value of the absolute values of any of the in-phase component or the quadrature component obtained by quadrature detection of the received signal is determined as the received signal level, and the phase data obtained by demodulating the phase-modulated signal is used. Diversity reception in which a phase error from an ideal phase is accumulated for a predetermined amount of symbol data to obtain a phase error accumulation value, and reception data from a reception branch is selected from the reception signal level and the phase error accumulation value. Method. The selection of the reception data is performed when the difference between the reception signal level of the reception branch having the highest reception signal level and the reception signal level of the other reception branches is larger than a predetermined threshold. 3. The diversity receiving method according to claim 1, wherein a signal received from the branch is selected. When the difference between the received signal level of the received branch having the largest received signal level and the received signal level of the other received branches is smaller than a predetermined threshold, the selection of the received data has the smallest phase error accumulated value. 3. The diversity reception method according to claim 2, wherein a reception signal from a reception branch is selected. The selection of the reception data is performed between the reception branch having the smallest phase error accumulation value and the reception branch in which the difference in the phase error accumulation value between the other reception branches is smaller than a predetermined threshold. 3. The diversity receiving method according to claim 2, wherein a receiving branch having the highest received signal level is selected from the following. As a result of performing the frame synchronization process using the received signal, from the frame synchronization determination result indicating either the success or the unsuccessful establishment of the frame synchronization, it is selected from the candidates of the reception branch in which the frame synchronization is successfully established. The diversity receiving method according to any one of claims 1 to 5, wherein: Received signal level detection means for setting the average of the absolute values of either the in-phase component or the quadrature component obtained by quadrature detection of the received signal to the received signal level; and the received signal level obtained by the received signal level detection means. And a receiving branch selecting means for comparing received data among a plurality of receiving branches and selecting received data from a receiving branch having the highest received signal level. Using received signal level detecting means for setting the average of the absolute values of either the in-phase component or the quadrature component obtained by quadrature detection of the received signal to the received signal level, and phase data obtained by demodulating the phase modulated signal A phase error detecting means for detecting a phase error of the phase data from an ideal phase; a phase error accumulating means for obtaining a phase error accumulated value obtained by accumulating the phase error by predetermined symbol data; A diversity circuit comprising: a reception branch selecting unit that selects reception data from a reception branch from a reception signal level obtained by a detection unit and a phase error accumulation value obtained by the phase error accumulation unit. If the difference between the reception signal level of the reception branch having the highest reception signal level and the reception signal level of the other reception branches is larger than a predetermined threshold, the reception branch selection means selects the reception signal having the highest reception signal level. 8. The diversity circuit according to claim 7, wherein a signal received from the branch is selected. When the difference between the reception signal level of the reception branch having the largest reception signal level and the reception signal level of the other reception branches is smaller than a predetermined threshold value, the reception branch selecting means has the smallest phase error accumulated value. 9. The diversity circuit according to claim 8, wherein a signal received from a receiving branch is selected. The receiving branch selecting means, if there is a receiving branch having the smallest phase error accumulated value and a receiving branch in which the difference of the accumulated phase error between the other receiving branches is smaller than a predetermined threshold value, 9. The diversity circuit according to claim 8, wherein a receiving branch having the highest received signal level is selected from the following. The apparatus further includes a frame synchronization determination unit that outputs a frame synchronization determination result indicating either success or failure of establishment of frame synchronization as a result of performing frame synchronization processing using the received signal. 12. The diversity circuit according to claim 7, wherein a selection is made from reception branch candidates for which frame synchronization has been established, based on the frame synchronization determination result obtained. The timing is adjusted so that the received signal level, accumulated phase error value, frame synchronization determination result, and received data obtained based on the same received signal or a received signal within a predetermined time difference are input to the diversity circuit. 13. The diversity circuit according to claim 8, further comprising a timing adjusting unit. A receiving apparatus for receiving data received from the diversity circuit according to claim 7. 15. A communication apparatus comprising: the reception apparatus according to claim 14; and a transmission apparatus that transmits data including frame synchronization data by phase-modulating the data.

Images