JP2004260322A

JP2004260322A - Multi-carrier wireless communication system, transmitting apparatus and receiving apparatus

Info

Publication number: JP2004260322A
Application number: JP2003046193A
Authority: JP
Inventors: Akinori Taira; 明徳平
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2003-02-24
Filing date: 2003-02-24
Publication date: 2004-09-16

Abstract

【課題】より良好な通信特性を実現可能なマルチキャリア無線通信システムを得ること。
【解決手段】本発明のマルチキャリア無線通信システムは、送信側の通信装置が、チャネル毎の送信信号に対して畳み込み符号化処理を行う畳み込み符号化部１，２と、ＳＴＣ処理を行うＳＴＣ部５と、を備え、受信側の通信装置が、送受信アンテナ間の伝送路を推定する伝送路推定部２５と、所定の受信信号行列を生成する受信信号行列生成部２４と、伝送路推定結果に基づいてチャネル毎の等化行列を生成する等化行列生成部２６と、チャネル毎に送信信号を推定する乗算器２７，２８と、送信信号の推定結果からチャネル毎に信頼度情報およびメトリック情報を生成するメトリック生成部２９，３０と、信頼度情報およびメトリック情報を用いてチャネル毎に最尤系列推定による誤り訂正処理を行うＭＬＳＥ誤り訂正部３１，３２と、を備える。
【選択図】図２A multicarrier wireless communication system capable of realizing better communication characteristics is provided.
In a multi-carrier wireless communication system according to the present invention, a communication device on a transmitting side performs convolutional encoding on a transmission signal for each channel, and an STC unit for performing STC processing. 5, a communication apparatus on the receiving side includes: a transmission path estimating section 25 for estimating a transmission path between the transmitting and receiving antennas; a reception signal matrix generating section 24 for generating a predetermined reception signal matrix; An equalization matrix generation unit 26 that generates an equalization matrix for each channel based on the above, multipliers 27 and 28 that estimate a transmission signal for each channel, and reliability information and metric information for each channel based on the estimation result of the transmission signal. Metric generation units 29 and 30 for generating, MLSE error correction units 31 and 32 for performing error correction processing by maximum likelihood sequence estimation for each channel using reliability information and metric information, Provided.
[Selection] Fig. 2

Description

【０００１】
【発明の属する技術分野】
本発明は、通信方式としてマルチキャリア変復調方式を採用する通信システムに関するものであり、特に、送信ダイバーシチ技術を利用したマルチキャリア無線通信システムに関するものである。
【０００２】
【従来の技術】
以下、従来のマルチキャリア無線通信システムについて説明する。たとえば、広帯域信号を移動体通信環境において送受信する場合は、周波数選択性フェージングの克服が必要となる。周波数選択性フェージングへの対応技術の一つとしては、マルチキャリア変復調方式、特に、ＯＦＤＭ（ＯｒｔｈｏｇｏｎａｌＦｒｅｑｕｅｎｃｙＤｉｖｉｓｉｏｎＭｕｌｔｉｐｌｅｘｉｎｇ）が各種無線システムに採用されている。一方、さらなる伝送容量の増大のために、複数アンテナを用いて２つ以上の信号を同時に伝送するＭＩＭＯ（ＭｕｌｔｉｐｌｅＩｎｐｕｔＭｕｌｔｉｐｌｅＯｕｔｐｕｔ）システムが注目を集めている。このＭＩＭＯシステムは、ＳＤＭ（ＳｐａｃｅＤｉｖｉｓｉｏｎＭｕｌｔｉｐｌｅｘｉｎｇ）による方式と、送信ダイバーシチによる方式と、に分けられる。本発明は、後者に属するものでＳＴＣ（ＳｐａｃｅＴｉｍｅＣｏｄｉｎｇ：時空符号化）と呼ばれる送信ダイバーシチ技術に基づいたものである。
【０００３】
ここで、従来のＭＩＭＯ送受信機の構成および動作について説明する（非特許文献１参照）。ここでは、２つの送信アンテナを有する場合の構成（２チャネル構成）を、一例として説明する。
【０００４】
従来のＭＩＭＯ送信機は、２つのチャネルの送信信号Ｓ１０１，Ｓ１０２をリードソロモン符号などのブロック符号により個別に符号化するブロック符号符号化部と、符号化後信号Ｓ１０３，Ｓ１０４を個別に変調し、それらの変調信号Ｓ１０５，１０６を各サブキャリアに配置する変調部と、各チャネルの変調信号Ｓ１０５，Ｓ１０６にＳＴＣ処理による符号化を行い、送信アンテナと送信時刻を決定するＳＴＣ部と、前記決定後のサブキャリア上の信号Ｓ１０７，Ｓ１０８を逆フーリエ変換により個別に時間軸信号に変換し、さらに、ガードインターバルの付加処理などを行うＩＦＦＴ（ＩｎｖｅｒｓｅＦａｓｔＦｏｕｒｉｅｒＴｒａｎｓｆｏｒｍ）部と、各ベースバンド信号を個別に高周波帯に変換するＩＦ／ＲＦ部と、ＩＦ／ＲＦ部の出力信号に個別に対応する送信アンテナで構成される。
【０００５】
また、従来のＭＩＭＯ受信機は、受信アンテナと、高周波信号をダウンコンバートしてベースバンド信号Ｓ１１５に変換するＩＦ／ＲＦ部と、ベースバンド信号（時間軸信号）Ｓ１１５を周波数軸信号Ｓ１１６に変換するＦＦＴ（ＦａｓｔＦｏｕｒｉｅｒＴｒａｎｓｆｏｒｍ）部と、周波数軸信号Ｓ１１６中のパイロット信号を用いて伝送路推定を行い、伝送路情報Ｓ１１７を提供する伝送路推定部と、伝送路情報Ｓ１１７と周波数軸信号Ｓ１１６に基づいてＭＬＤ（ＭａｘｉｍｕｍＬｉｋｌｉｈｏｏｄＤｅｔｅｃｔｉｏｎ：最尤判定）により各チャネルの受信信号Ｓ１１８，Ｓ１１９を出力するＭＬＤ部と、受信信号Ｓ１１８，Ｓ１１９に対して誤り訂正を行って最終的な受信信号Ｓ１２０，Ｓ１２１を出力するブロック符号誤り訂正部で構成される。
【０００６】
つづいて、従来のＭＩＭＯ送受信機の動作について説明する。まず、ＭＩＭＯ送信機では、符号化部，変調部が、同時に送信する２チャネルのユーザデータＳ１０１，Ｓ１０２に対して個別に誤り訂正用符号化処理および変調処理を実行し、変調信号をサブキャリア上に配置する。ＳＴＣ部では、サブキャリア上の変調信号Ｓ１０５，Ｓ１０６に対して送信アンテナと送信時刻を割り当て、すなわち、ＳＴＣ処理を行い、再度サブキャリア上の信号Ｓ１０７，Ｓ１０８を出力する。そして、これらの信号は、ＩＦＦＴ部にて個別に時間軸信号に変換され、ガードインターバルの付加処理などが行われた後、ＩＦ／ＲＦ部にてアップコンバートされ、送信される。なお、ここでは、パイロット信号の処理などは省略した。
【０００７】
一方、ＭＩＭＯ受信機側では、受信アンテナから入力される信号をＩＦ／ＲＦ部にてダウンコンバートし、ベースバンド信号Ｓ１１５を出力する。ベースバンド信号Ｓ１１５には、一般的にパイロット信号（既知信号）とユーザデータが含まれており、そのパイロット信号は、伝送路推定部に送られて伝送路情報Ｓ１１７の算出に使われる。また、ユーザデータは、ＦＦＴ部にて周波数軸信号Ｓ１１６に変換される。つぎに、ＭＬＤ部では、受信信号Ｓ１１６に対するＭＬＤ処理により送信系列を推定する。すなわち、送信した可能性のあるすべての情報系列に対して、伝送路情報Ｓ１１７を用いてレプリカを算出し、その結果と周波数軸信号１１６との比較を行い、各チャネルの最も尤度の高い（確からしい）系列を受信信号Ｓ１１８，Ｓ１１９として出力する。ブロック符号誤り訂正部では、これらの系列に対して誤り訂正処理を実行し、最終的な受信信号Ｓ１２０，Ｓ１２１を出力する。
【０００８】
なお、ＳＴＣの理論的な信号処理については、下記非特許文献２，３に詳細に記述されている。
【０００９】
【非特許文献１】
電子情報通信学会２００２年ソサイエティ大会Ｂ−５−３４「ＭＣ−ＣＤＭＡＳｙｓｔｅｍｕｓｉｎｇＳＤＭＳｃｈｅｍｅｆｏｒＢｒｏａｄｂａｎｄＭｏｂｉｌｅＣｏｍｍｕｎｉｃａｔｉｏｎｓ」
【非特許文献２】
Ｓ．Ｍ．Ａｌａｍｏｕｔｉ，“ＡＳｉｍｐｌｅＴｒａｎｓｍｉｔＤｉｖｅｒｓｉｔｙＴｅｃｈｎｉｑｕｅｆｏｒＷｉｒｅｌｅｓｓＣｏｍｍｕｎｉｃａｔｉｏｎｓ”，ＩＥＥＥＪ．Ｓｅ−ｌｅｃｔｅｄＡｒｅａｓｉｎＣｏｍｍｕｎｉｃａｔｉｏｎｓ，ｖａｌ．１６，ｐｐ．１４５１−１４５８，Ｏｃｔ．１９９８．
【非特許文献３】
Ｖ．Ｔａｒｏｋｈ，Ｈ．Ｊａｆａｒｋｈａｎｉ，Ａ．Ｒ．Ｃａｌｄｅｒｂａｎｋ，“Ｓｐａｃｅ−ｔｉｍｅＢｌｏｃｋＣｏｄｉｎｇｆｏｒＷｉｒｅｌｅｓｓＣｏｍｍｕｎｉｃａｔｉｏｎｓ：ＰｅｒｆｏｒｍａｎｃｅＲｅｓｕｌｔｓ”，ＩＥＥＥＪｏｕｒｎａｌＯｎＳｅｌｅｃｔｅｄＡｒｅａｓｉｎＣｏｍｍｕｎｉｃａｔｉｏｎｓ，Ｖｏｌ．１７，ｐｐ．４５１−４６０，Ｎｏ．３，Ｍａｒｃｈ１９９９．
【００１０】
【発明が解決しようとする課題】
しかしながら、上記、従来のマルチキャリア無線通信システムにおいては、復調にＭＬＤを使用するため、受信側が、系列判定時に送信した可能性のあるすべての系列のレプリカと受信信号とを比較し、最尤系列を出力する。そのため、特に、多値変調時に、比較すべき系列が莫大に増加する、という問題があった。また、上記と同様の理由で、無線通信に優れた特性を発揮する畳み込み符号を適用することが非常に困難になる、という問題があった。
【００１１】
本発明は、上記に鑑みてなされたものであって、複数の送信アンテナを備え、ＳＴＣ処理を用いた場合であっても、良好な通信特性を実現可能なマルチキャリア（キャリア数１の場合も含む）無線通信システムを得ることを目的とする。
【００１２】
【課題を解決するための手段】
上述した課題を解決し、目的を達成するために、本発明にかかるマルチキャリア無線通信システムにあっては、複数の送信アンテナを備え、１つまたは複数のキャリアを用いた通信を行うマルチキャリア無線通信システムであって、送信側の通信装置が、チャネル毎の送信信号に対して個別に畳み込み符号化処理を行う畳み込み符号化手段と、ＳＴＣ（ＳｐａｃｅＴｉｍｅＣｏｄｉｎｇ：時空符号化）処理による送信ダイバーシチを実現するＳＴＣ手段と、を備え、受信側の通信装置が、送受信アンテナ間の伝送路を推定する伝送路推定手段と、各時刻の受信信号を示す列ベクトル（受信信号行列）を生成する受信信号行列生成手段と、前記伝送路推定結果に基づいて、ＳＴＣの信号配置マトリクスから求まる信号配置マトリクス（チャネル毎の等化行列）を生成する等化行列生成手段と、前記受信信号行列と前記チャネル毎の等化行列に基づいて、チャネル毎に送信信号を推定する送信信号推定手段と、前記送信信号の推定結果からチャネル毎に信頼度情報およびメトリック情報を生成するメトリック生成手段と、前記信頼度情報および前記メトリック情報を用いてチャネル毎に最尤系列推定による誤り訂正処理を行う誤り訂正手段と、を備えることを特徴とする。
【００１３】
この発明によれば、ＳＴＣを用いるＭＩＭＯシステムにおいて、ＭＬＤを使用することなく、送信信号の推定値を求めることにより、装置構成の大幅な簡略化と畳み込み符号を用いた効率的な誤り訂正を実現する。
【００１４】
【発明の実施の形態】
以下に、本発明にかかるマルチキャリア無線通信システム、送信装置および受信装置の実施の形態を図面に基づいて詳細に説明する。なお、この実施の形態によりこの発明が限定されるものではない。
【００１５】
実施の形態１．
まず、本発明にかかるマルチキャリア無線通信システムにおいて実行される処理を理論的に説明する。なお、ここでは、サブキャリア数を１として説明する。
【００１６】
ＳＴＣは、送信データを空間（アンテナ）および時間で多重して送信し、受信側でダイバーシチ効果を得る手法である。前述した非特許文献２，３によれば、チャネル（１）の送信信号をＳ_１，チャネル（２）の送信信号をＳ_２とした場合に、時刻（１）にアンテナ（１）からＳ_１を，アンテナ（２）からＳ_２を、時刻（２）にアンテナ（１）から−Ｓ_２ ^＊を，アンテナ（２）からＳ_１ ^＊を、それぞれ送信する。このとき、受信アンテナを１本とし、送信アンテナ（１）から受信アンテナへの伝送路情報をｈ_１とし、送信アンテナ（２）から受信アンテナへの伝送路情報をｈ_２とした場合、時刻（１），（２）の受信信号ｒ_１，ｒ_２は次式（１）で表すことができる。なお、ｎ_１，ｎ_２は時刻毎の雑音を表す。
【００１７】
【数１】

【００１８】
また、従来のＳＴＣ復号には、ＭＬＤが用いられているため、次式（２）により、考えうるすべての送信系列ｕ_１，ｕ_２に対して受信信号のレプリカｒ_１´，ｒ_２´を生成する。
【００１９】
【数２】

【００２０】
また、メトリックＭは、次式（３）で定義される。
【００２１】
【数３】

【００２２】
ＳＴＣでは、送信時の信号配置マトリクスが直交行列となるため、メトリックＭを最小化する送信系列ｕ_１，ｕ_２は、それぞれ独立に求めることができる。しかしながら、多値変調時には計算量が増加し、実現は非常に困難なものとなる。
【００２３】
そこで、本発明にかかるシステムでは、ＳＴＣ復号にＭＬＤを用いずに、送信信号の推定値を直接求める手法を提供する。送信信号を直接推定するためには、受信信号が次式（４）の形で記述できる必要がある。
【００２４】
【数４】

【００２５】
なお、Ｙは各時刻の受信信号を示す列ベクトルを表し、ＧはＳＴＣの信号配置マトリクスＳから求まる信号配置マトリクスを表し、Ｘは、たとえば、送信信号系列の列ベクトルで、チャネル数が４の場合は、次式（５）のように表現できる。ただし、ｎは各時刻の雑音を示す列ベクトルである。
【００２６】
【数５】

【００２７】
ＳＴＣの信号配置マトリクスＳからＧを算出できれば、送信信号の推定値を直接算出することができる。詳細は省略するが、たとえば、「同一信号が複数アンテナから同時送信されず、一つの送信情報の実数部，虚数部が分離して送信されることはない」場合には、Ｇの算出が可能である。一例として、前述の非特許文献３に示すように、３つのアンテナを用いた４チャネル送信時のＳＴＣ信号配置マトリクスが、次式（６）として示されている場合、信号配置マトリクスＧは、次式（７）のように計算することができる。
【００２８】
【数６】

【００２９】
【数７】

【００３０】
このとき、実際に送信に使用されるのはＳであるが、各時刻の受信信号ｒ_ｔと上記式（７）内のｙ_ｔは、一部が複素共役の関係にあるだけで、簡単に変換が可能である。したがって、送信信号を表す行列Ｘを求めるためには、上記式（４）の左辺と右辺にＧの逆行列（Ｇ^−１）を乗算し、次式（８）に示す演算を行う。
【００３１】
【数８】

【００３２】
なお、ＳＴＣを規定する行列Ｓの性質から、次式（９）が成立する。ただし、Ｔは転置共役を表し、αは定数であり、この場合、α＝２（｜ｈ_１｜^２＋｜ｈ_２｜^２＋｜ｈ_３｜^２）である。
【００３３】
【数９】

【００３４】
この性質を利用すると、次式（１０）が成立し、逆行列の演算も不要となる。
【００３５】
【数１０】

【００３６】
また、上記式（１０）から、送信信号の平均電力値をＰとし、平均雑音電力値をσ^２とした場合の、受信信号の信頼度情報であるＳ／Ｎ比（ＳｉｇｎａｌｔｏＮｏｉｓｅｒａｔｉｏ）を、次式（１１）のように規定することができる。この信頼度情報を誤り訂正処理に用いれば、受信特性を向上させることができる。
【００３７】
【数１１】

【００３８】
つづいて、上記理論を実現するマルチキャリア無線通信システムの送信側の通信装置（以下、送信装置と呼ぶ）および受信側の通信装置（以下、受信装置と呼ぶ）の動作を、図面を用いて具体的に説明する。
【００３９】
図１は、本発明にかかるマルチキャリア通信システムに含まれる送信装置の実施の形態１の構成を示す図である。この送信装置は、各チャネル（図示のチャネル（１），チャネル（２）に相当）の送信信号Ｓ１，Ｓ２に対して個別に畳み込み符号化を行う畳み込み符号化部１，２と、符号化後信号Ｓ３，Ｓ４を個別に変調し、それらの変調信号Ｓ５，Ｓ６を各サブキャリアに配置する変調部３，４と、各チャネルの変調信号Ｓ５，Ｓ６に対してＳＴＣ処理による符号化を行い、送信アンテナと送信時刻を決定するＳＴＣ部５と、ＳＴＣ部５の処理で決定したサブキャリア上の信号Ｓ７，Ｓ８を逆フーリエ変換により個別に時間軸信号に変換し、さらに、ガードインターバル付加処理などを行うＩＦＦＴ部６，７と、各ベースバンド信号を個別に高周波帯に変換するＩＦ／ＲＦ部８，９と、ＩＦ／ＲＦ部８，９の出力信号に個別に対応する送信アンテナ１０，１１で構成される。
【００４０】
まず、送信装置では、畳み込み符号化部１，２が、同時に送信する２チャネルの送信信号（ユーザデータ）Ｓ１，Ｓ２に対して個別に誤り訂正用符号化処理を行い、符号化後信号Ｓ３，Ｓ４を生成する。なお、これに限らず、たとえば、単一の情報源（ユーザデータ）に対して畳み込み符号化を行い、その後のデータを複数チャネルに分割してもよい。つぎに、変調部３，４が、所定の変調処理を実行し、変調信号Ｓ５，Ｓ６をサブキャリア上に配置する。
【００４１】
つぎに、ＳＴＣ部５が、サブキャリア上の変調信号Ｓ５，Ｓ６に対して送信アンテナと送信時刻を割り当て、すなわち、ＳＴＣ処理を行い、再度サブキャリア上の信号Ｓ７，Ｓ８を出力する。そして、これらの信号は、ＩＦＦＴ部６，７にて個別に時間軸信号に変換され、ガードインターバル付加処理などが行われた後、ＩＦ／ＲＦ部８，９にてアップコンバートされ、それぞれ送信アンテナ１０，１１から送信される。なお、ここでは、パイロット信号の処理などは省略する。
【００４２】
図２は、本発明にかかるマルチキャリア通信システムに含まれる受信装置の実施の形態１の構成を示す図である。この受信装置は、受信アンテナ２１と、高周波信号をダウンコンバートしてベースバンド信号Ｓ２１に変換するＩＦ／ＲＦ部２２と、ベースバンド信号（時間軸信号）Ｓ２１を周波数軸信号Ｓ２２（上記受信信号ｒ_ｔに相当）に変換するＦＦＴ部２３と、ＦＦＴ部２３から出力される周波数軸信号Ｓ２２から復調に必要な受信信号行列Ｓ２４（上記列ベクトルＹに相当）を生成する受信信号行列生成部２４と、周波数軸信号Ｓ２１中のパイロット信号を用いて伝送路推定を行い、アンテナ間の伝送路情報Ｓ２３を提供する伝送路推定部２５と、伝送路情報Ｓ２３から各チャネル用の等化行列Ｓ２５，Ｓ２６（全チャネル分でＧ^Ｔに相当）を生成する等化行列生成部２６と、受信信号行列Ｓ２４と等化行列Ｓ２５，Ｓ２６とを個別に乗算し、上記αＸ＋Ｇ^Ｔ×ｎに相当する各チャネルの送信信号推定値Ｓ２７，Ｓ２８を生成する乗算器２７，２８と、送信信号推定値Ｓ２７，Ｓ２８を用いて誤り訂正用の軟判定メトリック情報Ｓ２９，Ｓ３０を生成するメトリック生成部２９，３０と、軟判定メトリック情報Ｓ２９，Ｓ３０に基づいてビタビ復号などの最尤系列推定を行い、最終的な受信信号Ｓ３１，Ｓ３２を出力するＭＬＳＥ（ＭａｘｉｍｕｍＬｉｋｅｌｉｈｏｏｄＳｅｑｕｅｎｃｅＥｓｔｉｍａｔｉｏｎ）誤り訂正部３１，３２で構成される。
【００４３】
まず、受信装置では、受信アンテナ２１から入力される信号をＩＦ／ＲＦ部２２にてダウンコンバートし、ベースバンド信号Ｓ２１を出力する。ベースバンド信号Ｓ２１には、一般的にパイロット信号（既知信号）とユーザデータが含まれており、そのパイロット信号は、伝送路推定部２５に送られて伝送路情報Ｓ２３の算出に使われる。また、ユーザデータは、ＦＦＴ部２３にて周波数軸信号Ｓ２２に変換される。
【００４４】
つぎに、受信信号行列生成部２４が、周波数軸信号Ｓ２２（上記ｒ_ｔ）を受信信号行列Ｓ２４（送信信号推定に必要な受信信号Ｙ）に変換する。この処理は、信号配置マトリクスＳが与えられた段階で確定するものである。つぎに、等化行列生成部２６が、伝送路情報Ｓ２３に基づいて送信信号の推定に用いる等化行列Ｓ２５，Ｓ２６を計算する。つぎに、乗算器２７，２８が、等化行列Ｓ２５、Ｓ２６と受信信号行列Ｓ２４とを乗算し、各チャネルの送信信号推定値Ｓ２７，Ｓ２８を生成する。
【００４５】
つぎに、メトリック生成部２９，３０が、これらの推定値に基づいて誤り訂正用の軟判定メトリック情報（上記信頼度情報を含む）Ｓ２９，Ｓ３０を生成し、最後に、ＭＬＳＥ誤り訂正部３１，３２が、ビタビ復号等の最尤系列推定（ＭＬＳＥを用いた誤り訂正処理）を行い、最終的な受信信号Ｓ３１，Ｓ３２を出力する。
【００４６】
このように、本実施の形態においては、ＳＴＣを用いるＭＩＭＯシステムにおいて、ＭＬＤを使用することなく、上記処理で送信信号の推定値を求める構成とした。これにより、装置構成の大幅な簡略化と畳み込み符号を用いた効率的な誤り訂正が適用できるので、簡易な構成で良好な受信特性を実現できる。
【００４７】
実施の形態２．
図３は、本発明にかかるマルチキャリア通信システムに含まれる受信装置の実施の形態２の構成を示す図である。この受信装置は、伝送路のコヒーレント帯域幅を測定し、その測定結果であるコヒーレント帯域幅情報Ｓ４１を出力するコヒーレント帯域測定部４１と、周波数軸信号Ｓ２１中のパイロット信号とコヒーレント帯域幅情報Ｓ４１とを用いて伝送路推定を行い、アンテナ間の伝送路情報Ｓ２３を提供する伝送路推定部２５ａと、を含む構成とした。なお、先に説明した実施の形態１と同様の構成については、同一の符号を付してその説明を省略する。ここでは、実施の形態１と異なる動作についてのみ説明する。
【００４８】
コヒーレント帯域測定部４１では、ベースバンド信号Ｓ２１を定期的に観測し、現在の伝送路におけるコヒーレント帯域幅（伝送路がほぼ一定と見なせる周波数幅）を算出する。通常、この算出には既知信号が必要となるため、パイロット信号部分が多く用いられる。そして、その算出結果であるコヒーレント帯域幅情報Ｓ４１を伝送路推定部２５ａへ通知する。
【００４９】
伝送路推定部２５ａでは、コヒーレント帯域情報Ｓ４１により、信号帯域を、同一の伝送路情報を持ついくつかのサブキャリアグループに分割する。そして、コヒーレント帯域幅内はほぼ一定の伝送路と見なせることから、この帯域幅内の１サブキャリアについて伝送路推定を行う。すなわち、本実施の形態では、このグループ内において、一度だけ伝送路推定，等化行列の生成を行い、グループ内の全てのサブキャリアで同一の等化行列を使用して、送信信号推定値Ｓ２７，Ｓ２８を算出する。なお、伝送路推定部２５ａが、サブキャリアグループ内の複数サブキャリアについて伝送路推定を行い、その結果を平均化した信号を伝送路情報Ｓ１３としてもよい。
【００５０】
このように、本実施の形態においては、信号帯域を同一の伝送路情報を持ついくつかのサブキャリアグループに分割し、このグループ内において一度だけ伝送路推定，等化行列の生成を行う構成とした。これにより、計算量を大幅に削減することが可能となり、装置構成のさらなる簡略化を実現できる。
【００５１】
実施の形態３．
図４は、本発明にかかるマルチキャリア通信システムに含まれる送信装置の実施の形態３の構成を示す図である。この送信装置は、各チャネルの信号に対してビームフォーミングを行うビームフォーミング部５１，５２を含む構成とした。なお、先に説明した実施の形態１と同様の構成については、同一の符号を付してその説明を省略する。ここでは、実施の形態１と異なる動作についてのみ説明する。
【００５２】
ビームフォーミング部５１，５２では、ＳＴＣ処理後のサブキャリア上の信号Ｓ７，Ｓ８に対して複数アンテナによる送信方向制御（チャネル毎のビームフォーミング）を行うため、各チャネルのデータにウェイトを乗算し、各送信アンテナに割り当てる。なお、図４では、送信アンテナを２つとしているが、さらに多くのアンテナを備えることとしてもよい。一方、受信側では、伝送路推定部２５が、チャネル毎の伝送路情報を推定する。
【００５３】
このように、本実施の形態においては、実施の形態１と同様に、ＳＴＣを用いるＭＩＭＯシステムにおいて、ＭＬＤを使用することなく、送信信号の推定値を求める構成とした。これにより、装置構成の大幅な簡略化と畳み込み符号を用いた効率的な誤り訂正が適用できるので、簡易な構成で良好な受信特性を実現できる。
【００５４】
【発明の効果】
以上、説明したとおり、本発明によれば、たとえば、ＳＴＣを用いるＭＩＭＯシステムにおいて、ＭＬＤを使用することなく送信信号の推定値を求める構成とした。これにより、装置構成の大幅な簡略化と畳み込み符号を用いた効率的な誤り訂正が適用できるので、簡易な構成で良好な受信特性を実現できる、という効果を奏する。
【図面の簡単な説明】
【図１】本発明にかかるマルチキャリア通信システムに含まれる送信装置の実施の形態１の構成を示す図である。
【図２】本発明にかかるマルチキャリア通信システムに含まれる受信装置の実施の形態１の構成を示す図である。
【図３】本発明にかかるマルチキャリア通信システムに含まれる受信装置の実施の形態２の構成を示す図である。
【図４】本発明にかかるマルチキャリア通信システムに含まれる送信装置の実施の形態３の構成を示す図である。
【符号の説明】
１，２畳み込み符号化部、３，４変調部、５ＳＴＣ部、６，７ＩＦＦＴ部、８，９ＩＦ／ＲＦ部、１０，１１送信アンテナ、２１受信アンテナ、２２ＩＦ／ＲＦ部、２３ＦＦＴ部、２４受信信号行列生成部、２５，２５ａ伝送路推定部、２６等化行列生成部、２７，２８乗算器、２９，３０メトリック生成部、３１，３２ＭＬＳＥ誤り訂正部、４１コヒーレント帯域測定部、５１，５２ビームフォーミング部。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a communication system employing a multicarrier modulation / demodulation system as a communication system, and more particularly to a multicarrier wireless communication system using a transmission diversity technology.
[0002]
[Prior art]
Hereinafter, a conventional multi-carrier wireless communication system will be described. For example, when transmitting and receiving wideband signals in a mobile communication environment, it is necessary to overcome frequency selective fading. As one of the techniques for coping with frequency selective fading, a multicarrier modulation / demodulation method, particularly, OFDM (Orthogonal Frequency Division Multiplexing) has been adopted for various wireless systems. On the other hand, in order to further increase the transmission capacity, a Multiple Input Multiple Output (MIMO) system that simultaneously transmits two or more signals using a plurality of antennas has attracted attention. This MIMO system is divided into a system based on SDM (Space Division Multiplexing) and a system based on transmission diversity. The present invention belongs to the latter and is based on a transmission diversity technology called STC (Space Time Coding).
[0003]
Here, the configuration and operation of a conventional MIMO transceiver will be described (see Non-Patent Document 1). Here, a configuration having two transmission antennas (two-channel configuration) will be described as an example.
[0004]
A conventional MIMO transmitter separately modulates a block code encoding unit that individually encodes transmission signals S101 and S102 of two channels using a block code such as a Reed-Solomon code, and signals S103 and S104 after encoding. A modulation section for arranging these modulation signals S105 and 106 on each subcarrier, an STC section for performing coding by STC processing on the modulation signals S105 and S106 of each channel to determine a transmission antenna and a transmission time, The signals S107 and S108 on the subcarriers are individually converted into time axis signals by inverse Fourier transform, and an IFFT (Inverse Fast Fourier Transform) unit for performing processing such as adding a guard interval, and each baseband signal is individually IF / RF section for converting to high frequency band, IF / RF It consists of transmitting antennas individually corresponding to the output signal.
[0005]
Further, the conventional MIMO receiver converts a receiving antenna, an IF / RF unit that down-converts a high-frequency signal into a baseband signal S115, and converts a baseband signal (time-axis signal) S115 into a frequency-axis signal S116. Based on an FFT (Fast Fourier Transform) section, a transmission path estimation section that performs transmission path estimation using a pilot signal in the frequency axis signal S116 and provides transmission path information S117, and the transmission path information S117 and the frequency axis signal S116. MLD (Maximum Likelihood Detection: maximum likelihood determination) to output received signals S118 and S119 of each channel, and perform error correction on received signals S118 and S119 to output final received signals S120 and S121. Block error correction section It consists of.
[0006]
Next, the operation of the conventional MIMO transceiver will be described. First, in the MIMO transmitter, the coding unit and the modulation unit individually execute error correction coding processing and modulation processing on the two-channel user data S101 and S102 that are transmitted simultaneously, and convert the modulated signal onto the subcarrier. To place. The STC unit assigns a transmission antenna and a transmission time to the modulated signals S105 and S106 on the subcarrier, that is, performs STC processing, and outputs signals S107 and S108 on the subcarrier again. Then, these signals are individually converted into time axis signals in the IFFT unit, and after guard interval addition processing is performed, the signals are up-converted in the IF / RF unit and transmitted. Here, the processing of the pilot signal and the like are omitted.
[0007]
On the other hand, on the MIMO receiver side, the signal input from the receiving antenna is down-converted by the IF / RF unit, and the baseband signal S115 is output. The baseband signal S115 generally includes a pilot signal (known signal) and user data, and the pilot signal is sent to the transmission path estimator and used for calculating the transmission path information S117. The user data is converted into a frequency axis signal S116 by the FFT unit. Next, the MLD unit estimates a transmission sequence by MLD processing on the received signal S116. That is, for all information sequences that may have been transmitted, replicas are calculated using the transmission path information S117, the result is compared with the frequency axis signal 116, and the highest likelihood of each channel is calculated ( Probably) sequences are output as received signals S118 and S119. The block code error correction unit performs error correction processing on these sequences and outputs final received signals S120 and S121.
[0008]
The theoretical signal processing of the STC is described in detail in

Non-Patent Documents

2 and 3 below.
[0009]
[Non-patent document 1]
IEICE 2002 Society Conference B-5-34 "MC-CDMA System using SDM Scheme for Broadband Mobile Communications"
[Non-patent document 2]
S. M. Alamouti, "A Simple Transmit Diversity Technology for Wireless Communications", IEEE J. Org. See-Selected Areas in Communications, val. 16, pp. 1451-1458, Oct. 1998.
[Non-Patent Document 3]
V. Tarokh, H .; Jafarkhani, A .; R. Calderbank, "Space-time Block Coding for Wireless Communications: Performance Results", IEEE Journal On Selected Areas in Communications, Vol. 17, pp. 451-460, no. 3, March 1999.
[0010]
[Problems to be solved by the invention]
However, in the above-described conventional multi-carrier wireless communication system, since the MLD is used for demodulation, the receiving side compares replicas of all sequences that may have been transmitted at the time of sequence determination with the received signal, and determines the maximum likelihood sequence. Is output. Therefore, there is a problem that the number of sequences to be compared increases enormously, particularly during multi-level modulation. In addition, for the same reason as described above, there is a problem that it becomes very difficult to apply a convolutional code exhibiting excellent characteristics for wireless communication.
[0011]
The present invention has been made in view of the above, and has a plurality of transmission antennas and is capable of realizing good communication characteristics even when using STC processing. (Including) a wireless communication system.
[0012]
[Means for Solving the Problems]
In order to solve the above problems and achieve the object, a multicarrier radio communication system according to the present invention includes a plurality of transmission antennas, and performs multicarrier radio communication using one or more carriers. In a communication system, a communication device on a transmission side performs convolutional encoding means for individually performing convolutional encoding processing on a transmission signal for each channel, and transmission diversity by STC (Space Time Coding) processing. Transmission path estimating means for estimating a transmission path between the transmitting and receiving antennas, and a reception signal for generating a column vector (reception signal matrix) indicating a reception signal at each time. A signal arrangement matrix (channel) obtained from an STC signal arrangement matrix based on the matrix generation means and the transmission path estimation result. An equalization matrix for each channel, a transmission signal estimation unit for estimating a transmission signal for each channel based on the reception signal matrix and the equalization matrix for each channel, Metric generation means for generating reliability information and metric information for each channel from the estimation result, and error correction means for performing error correction processing by maximum likelihood sequence estimation for each channel using the reliability information and the metric information, It is characterized by having.
[0013]
According to the present invention, in a MIMO system using STC, an estimated value of a transmission signal is obtained without using MLD, thereby greatly simplifying the device configuration and achieving efficient error correction using convolutional codes. I do.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a multicarrier wireless communication system, a transmission device, and a reception device according to the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited by the embodiment.
[0015]
Embodiment 1 FIG.
First, processing executed in the multicarrier wireless communication system according to the present invention will be theoretically described. Here, the description is made on the assumption that the number of subcarriers is one.
[0016]
The STC is a technique of multiplexing transmission data in space (antenna) and time and transmitting the multiplexed data to obtain a diversity effect on the receiving side. According to

Non-Patent Documents

2 and 3 described above, _{S 1} transmission signal of the channel (1), when the transmission signal of the channel (2) was _{S 2,} _S from time (1) to the antenna (1) ₁ and the _{S 2} from the antenna (2), the time the _-S ^{2 *} (2) to the antenna (1), the _S ^{1 *} from antenna (2), respectively transmit. In this case, the receiving antenna and one, the transmission path information from the transmitting antenna (1) to the receiving antenna and h _1, when the transmission path information to the receiving antenna from the transmitting antenna (2) as a h _2, the time ( The received signals r ₁ and r _{2 in} 1) and (2) can be represented by the following equation (1). Note that n ₁ and n ₂ represent noise at each time.
[0017]
(Equation 1)

[0018]
Further, since MLD is used in the conventional STC decoding, replicas r ₁ ′ and r ₂ ′ of received signals for all conceivable transmission sequences u ₁ and u ₂ are calculated by the following equation (2). Generate.
[0019]
(Equation 2)

[0020]
The metric M is defined by the following equation (3).
[0021]
[Equation 3]

[0022]
In the STC, since the signal arrangement matrix at the time of transmission is an orthogonal matrix, the transmission sequences u ₁ and u ₂ that minimize the metric M can be obtained independently. However, the amount of calculation increases at the time of multi-level modulation, and it is very difficult to realize.
[0023]
Therefore, the system according to the present invention provides a method for directly obtaining an estimated value of a transmission signal without using MLD for STC decoding. In order to directly estimate the transmission signal, the reception signal needs to be described in the form of the following equation (4).
[0024]
(Equation 4)

[0025]
Here, Y represents a column vector indicating a received signal at each time, G represents a signal arrangement matrix obtained from a signal arrangement matrix S of STC, and X is, for example, a column vector of a transmission signal sequence and has four channels. The case can be expressed as in the following equation (5). Here, n is a column vector indicating noise at each time.
[0026]
(Equation 5)

[0027]
If G can be calculated from the signal arrangement matrix S of the STC, the estimated value of the transmission signal can be directly calculated. Although details are omitted, for example, in a case where “the same signal is not transmitted simultaneously from a plurality of antennas and the real part and the imaginary part of one transmission information are not transmitted separately”, G can be calculated. It is. As an example, as shown in the above-mentioned Non-Patent Document 3, when the STC signal arrangement matrix at the time of four-channel transmission using three antennas is represented by the following equation (6), the signal arrangement matrix G becomes It can be calculated as in equation (7).
[0028]
(Equation 6)

[0029]
(Equation 7)

[0030]
At this time, is actually used for transmission is S, y _t in the received signal r _t and the equation for each time (7) is only partly in the complex conjugate relationship, easily Conversion is possible. Therefore, in order to obtain the matrix X representing the transmission signal, the left side and the right side of the above equation (4) are multiplied by the inverse matrix of G (G ⁻¹ ), and the operation shown in the following equation (8) is performed.
[0031]
(Equation 8)

[0032]
Note that, from the property of the matrix S that defines the STC, the following equation (9) holds. However, T is denotes the transpose conjugate, alpha is a constant, in this case, alpha ₌ 2 is ^{_{^{^{(| 2 h 1 | 2 +}}}} | h 2 | 2 + | | h 3).
[0033]
(Equation 9)

[0034]
By utilizing this property, the following equation (10) is satisfied, and the calculation of the inverse matrix is not required.
[0035]
(Equation 10)

[0036]
From the above equation (10), when the average power value of the transmission signal is P and the average noise power value is σ ² , the S / N ratio (Signal to Noise ratio) which is the reliability information of the reception signal is , (11). If this reliability information is used for error correction processing, the reception characteristics can be improved.
[0037]
[Equation 11]

[0038]
Next, the operations of a transmitting-side communication device (hereinafter, referred to as a transmitting device) and a receiving-side communication device (hereinafter, referred to as a receiving device) of a multi-carrier wireless communication system that realizes the above theory will be described in detail with reference to the drawings. Will be explained.
[0039]
FIG. 1 is a diagram illustrating a configuration of a transmitting apparatus included in a multicarrier communication system according to a first embodiment of the present invention. The transmitting apparatus includes

convolutional encoding units

1 and 2 that individually perform convolutional encoding on transmission signals S1 and S2 of each channel (corresponding to channel (1) and channel (2) shown), The signals S3 and S4 are individually modulated, and the modulation units S3 and S4 that arrange the modulation signals S5 and S6 on each subcarrier, and the modulation signals S5 and S6 of each channel are subjected to encoding by STC processing. STC unit 5 for determining a transmitting antenna and a transmission time, and individually converting signals S7 and S8 on subcarriers determined by the processing of STC unit 5 into time axis signals by inverse Fourier transform, and further adding a guard interval and the like. , IF /

RF sections

8 and 9 for individually converting each baseband signal into a high-frequency band, and transmission antennas 10 individually corresponding to the output signals of IF /

RF sections

8 and 9 Composed of 11.
[0040]
First, in the transmitting device, the

convolutional encoders

1 and 2 individually perform error correction encoding on transmission signals (user data) S1 and S2 of two channels transmitted at the same time, and generate encoded signals S3 and S3. Generate S4. The present invention is not limited to this. For example, convolutional coding may be performed on a single information source (user data), and the subsequent data may be divided into a plurality of channels. Next,

modulators

3 and 4 execute a predetermined modulation process, and arrange modulation signals S5 and S6 on subcarriers.
[0041]
Next, STC section 5 assigns a transmission antenna and a transmission time to modulated signals S5 and S6 on the subcarrier, that is, performs STC processing, and outputs signals S7 and S8 on the subcarrier again. These signals are individually converted into time axis signals in

IFFT sections

6 and 7, and after guard interval addition processing is performed, the signals are up-converted in IF /

RF sections

8 and 9 and transmission antennas are respectively transmitted. Sent from 10 and 11. Here, the processing of the pilot signal and the like are omitted.
[0042]
FIG. 2 is a diagram illustrating a configuration of the first embodiment of the receiving device included in the multicarrier communication system according to the present invention. This receiving apparatus includes a receiving antenna 21, an IF / RF unit 22 for down-converting a high-frequency signal and converting it to a baseband signal S21, and a baseband signal (time-axis signal) S21 for a frequency-axis signal S22 (the reception signal r a FFT unit 23 to be converted to equivalent) in _t, the received signal matrix generation unit 24 that generates a received signal matrix necessary for demodulation from the frequency axis signal S22 output from the FFT unit 23 S24 (corresponding to the column vector Y) , A channel estimation unit 25 that performs channel estimation using a pilot signal in the frequency axis signal S21 and provides channel information S23 between antennas, and an equalization matrix S25, S26 for each channel from the channel information S23. an equalization matrix generation unit 26 for generating a (corresponding to ^{G T} in all channels), a reception signal matrix S24 equalization matrix S25, S26 multiplied separately, A multiplier 27 which generates the serial .alpha.X + ^{G T} × transmission of each channel corresponding to the n signal estimate S27, S28, the soft decision metric data S29, S30 for error correction using the transmission signal estimate S27, S28 MLSE (Maximum Likelihood Sequence Estimation) error for performing maximum likelihood sequence estimation such as Viterbi decoding based on the generated

metric generation units

29 and 30 and the soft decision metric information S29 and S30, and outputting final received signals S31 and S32. It comprises

correction units

31 and 32.
[0043]
First, in the receiving device, a signal input from the receiving antenna 21 is down-converted by the IF / RF unit 22 and a baseband signal S21 is output. The baseband signal S21 generally includes a pilot signal (known signal) and user data, and the pilot signal is sent to the transmission path estimator 25 and used for calculating the transmission path information S23. Further, the user data is converted into a frequency axis signal S22 by the FFT unit 23.
[0044]
Next, the reception signal matrix generation unit 24 into a frequency axis signal S22 (the _{r t)} (reception signal Y required transmit signal estimation) received signal matrix S24 a. This processing is determined when the signal arrangement matrix S is given. Next, the equalization matrix generator 26 calculates the equalization matrices S25 and S26 used for estimating the transmission signal based on the transmission path information S23. Next,

multipliers

27 and 28 multiply the equalization matrices S25 and S26 by the reception signal matrix S24 to generate transmission signal estimation values S27 and S28 for each channel.
[0045]
Next, the

metric generation units

29 and 30 generate soft-decision metric information for error correction (including the reliability information) S29 and S30 based on these estimated values, and finally, the MLSE

error correction units

31 and 30. 32 performs maximum likelihood sequence estimation (error correction processing using MLSE) such as Viterbi decoding, and outputs final received signals S31 and S32.
[0046]
Thus, in the present embodiment, in the MIMO system using the STC, the configuration is such that the estimated value of the transmission signal is obtained by the above processing without using the MLD. As a result, since the device configuration can be greatly simplified and efficient error correction using a convolutional code can be applied, good reception characteristics can be realized with a simple configuration.
[0047]
Embodiment 2 FIG.
FIG. 3 is a diagram showing a configuration of the receiving apparatus included in the multicarrier communication system according to the second embodiment of the present invention. The receiving apparatus measures a coherent bandwidth of a transmission path, and outputs a coherent bandwidth information S41 as a measurement result, a coherent bandwidth measuring unit 41, a pilot signal in a frequency axis signal S21 and coherent bandwidth information S41. And a transmission path estimating unit 25a for providing transmission path information S23 between antennas. The same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted. Here, only operations different from those in the first embodiment will be described.
[0048]
The coherent band measurement unit 41 periodically observes the baseband signal S21 and calculates a coherent bandwidth (frequency width in which the transmission path can be regarded as substantially constant) in the current transmission path. Normally, a known signal is required for this calculation, so that a pilot signal portion is often used. Then, it notifies the transmission path estimation unit 25a of the coherent bandwidth information S41, which is the calculation result.
[0049]
The transmission path estimating unit 25a divides the signal band into several subcarrier groups having the same transmission path information based on the coherent band information S41. Then, since the transmission path within the coherent bandwidth can be regarded as a substantially constant transmission path, the transmission path is estimated for one subcarrier within this bandwidth. That is, in the present embodiment, the transmission path estimation and the generation of the equalization matrix are performed only once in this group, and the same transmission matrix estimation value S27 is used for all the subcarriers in the group. , S28 are calculated. Note that the transmission path estimating unit 25a may perform transmission path estimation on a plurality of subcarriers in a subcarrier group, and use a signal obtained by averaging the results as transmission path information S13.
[0050]
As described above, the present embodiment divides a signal band into several subcarrier groups having the same transmission path information, and performs transmission path estimation and generation of an equalization matrix only once in this group. did. As a result, the amount of calculation can be significantly reduced, and the apparatus configuration can be further simplified.
[0051]
Embodiment 3 FIG.
FIG. 4 is a diagram illustrating a configuration of a transmitting apparatus included in a multicarrier communication system according to a third embodiment of the present invention. This transmitting apparatus is configured to include beam forming units 51 and 52 for performing beam forming on signals of respective channels. The same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted. Here, only operations different from those in the first embodiment will be described.
[0052]
The beamforming units 51 and 52 multiply the data of each channel by a weight in order to perform transmission direction control (beamforming for each channel) on the signals S7 and S8 on the subcarriers after the STC process by using a plurality of antennas. Assign to each transmitting antenna. Although two transmission antennas are shown in FIG. 4, more transmission antennas may be provided. On the receiving side, on the other hand, the transmission path estimation unit 25 estimates transmission path information for each channel.
[0053]
As described above, in the present embodiment, as in Embodiment 1, in the MIMO system using STC, the configuration is such that the estimated value of the transmission signal is obtained without using MLD. As a result, since the device configuration can be greatly simplified and efficient error correction using a convolutional code can be applied, good reception characteristics can be realized with a simple configuration.
[0054]
【The invention's effect】
As described above, according to the present invention, for example, in the MIMO system using the STC, the configuration is such that the estimated value of the transmission signal is obtained without using the MLD. As a result, a significant simplification of the device configuration and efficient error correction using a convolutional code can be applied, so that good reception characteristics can be realized with a simple configuration.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a first embodiment of a transmission device included in a multicarrier communication system according to the present invention.
FIG. 2 is a diagram illustrating a configuration of a first embodiment of a receiving device included in the multicarrier communication system according to the present invention.
FIG. 3 is a diagram showing a configuration of a receiving apparatus included in a multicarrier communication system according to a second embodiment of the present invention.
FIG. 4 is a diagram illustrating a configuration of a transmitting apparatus included in a multicarrier communication system according to a third embodiment of the present invention.
[Explanation of symbols]
1, 2 convolutional coding section, 3, 4 modulation section, 5 STC section, 6, 7 IFFT section, 8, 9 IF / RF section, 10, 11 transmission antenna, 21 reception antenna, 22 IF / RF section, 23 FFT Unit, 24 reception signal matrix generation unit, 25, 25a channel estimation unit, 26 equalization matrix generation unit, 27, 28 multiplier, 29, 30 metric generation unit, 31, 32 MLSE error correction unit, 41 coherent band measurement unit , 51, 52 Beam forming unit.

Claims

In a multi-carrier wireless communication system including a plurality of transmission antennas and performing communication using one or a plurality of carriers,
If the transmitting communication device is
Convolutional encoding means for individually performing convolutional encoding processing on a transmission signal for each channel;
STC means for realizing transmission diversity by STC (Space Time Coding) processing;
With
The communication device on the receiving side
Transmission path estimation means for estimating the transmission path between the transmitting and receiving antennas,
Reception signal matrix generation means for generating a column vector (reception signal matrix) indicating a reception signal at each time;
Equalization matrix generation means for generating a signal allocation matrix (equalization matrix for each channel) determined from the signal allocation matrix of the STC based on the transmission path estimation result;
Based on the received signal matrix and the equalization matrix for each channel, transmission signal estimation means for estimating a transmission signal for each channel,
Metric generating means for generating reliability information and metric information for each channel from the estimation result of the transmission signal,
Error correction means for performing error correction processing by maximum likelihood sequence estimation for each channel using the reliability information and the metric information,
A multi-carrier wireless communication system comprising:

Further, a coherent band measuring means for measuring a coherent bandwidth in a transmission line by observing a received signal,
With
Based on the measurement result, the transmission path estimation unit divides the signal band into several subcarrier groups having the same transmission path information, and performs transmission path estimation in units of the subcarrier groups.
The multi-carrier wireless communication system according to claim 1, wherein the equalization matrix generation unit generates an equalization matrix for each channel in units of the subcarrier groups.

In a multi-carrier wireless communication system including a plurality of transmission antennas and performing communication using one or a plurality of carriers,
If the transmitting communication device is
Convolutional encoding means for individually performing convolutional encoding processing on a transmission signal for each channel;
STC means for realizing transmission diversity by STC (Space Time Coding) processing;
Beam forming means having a beam forming function for each channel,
With
The communication device on the receiving side
Transmission path estimation means for estimating a transmission path for each channel;
Reception signal matrix generation means for generating a column vector (reception signal matrix) indicating a reception signal at each time;
Equalization matrix generation means for generating a signal allocation matrix (equalization matrix for each channel) determined from the signal allocation matrix of the STC based on the transmission path estimation result;
Based on the received signal matrix and the equalization matrix for each channel, transmission signal estimation means for estimating a transmission signal for each channel,
Metric generating means for generating reliability information and metric information for each channel from the estimation result of the transmission signal,
Error correction means for performing error correction processing by maximum likelihood sequence estimation for each channel using the reliability information and the metric information,
A multi-carrier wireless communication system comprising:

In a transmission device having a plurality of transmission antennas and performing communication using one or a plurality of carriers,
Convolutional encoding means for individually performing convolutional encoding processing on a transmission signal for each channel;
STC means for realizing transmission diversity by STC (Space Time Coding) processing;
A transmission device comprising:

Further, beam forming means having a beam forming function for each channel,
The transmission device according to claim 4, comprising:

In a receiving device constituting a multi-carrier wireless communication system,
Transmission path estimation means for estimating a transmission path between a plurality of transmitting antennas and a receiving antenna,
Reception signal matrix generation means for generating a column vector (reception signal matrix) indicating a reception signal at each time;
Equalization matrix generation means for generating a signal arrangement matrix (equalization matrix for each channel) obtained from a signal arrangement matrix of STC (Space Time Coding) based on the transmission path estimation result;
Based on the received signal matrix and the equalization matrix for each channel, transmission signal estimation means for estimating a transmission signal for each channel,
Metric generating means for generating reliability information and metric information for each channel from the estimation result of the transmission signal,
Error correction means for performing error correction processing by maximum likelihood sequence estimation for each channel using the reliability information and the metric information,
A receiving device comprising:

Further, a coherent band measuring means for measuring a coherent bandwidth in a transmission line by observing a received signal,
With
Based on the measurement result, the transmission path estimation unit divides the signal band into several subcarrier groups having the same transmission path information, and performs transmission path estimation in units of the subcarrier groups.
The receiving apparatus according to claim 6, wherein the equalization matrix generation unit generates an equalization matrix for each channel in units of the subcarrier groups.

In a receiving device constituting a multi-carrier wireless communication system,
Transmission path estimation means for estimating a transmission path for each channel;
Reception signal matrix generation means for generating a column vector (reception signal matrix) indicating a reception signal at each time;
Equalization matrix generation means for generating a signal arrangement matrix (equalization matrix for each channel) obtained from a signal arrangement matrix of STC (Space Time Coding) based on the transmission path estimation result;
Based on the received signal matrix and the equalization matrix for each channel, transmission signal estimation means for estimating a transmission signal for each channel,
Metric generating means for generating reliability information and metric information for each channel from the estimation result of the transmission signal,
Error correction means for performing error correction processing by maximum likelihood sequence estimation for each channel using the reliability information and the metric information,
A receiving device comprising: