JP3738705B2

JP3738705B2 - Adaptive antenna device

Info

Publication number: JP3738705B2
Application number: JP2001169236A
Authority: JP
Inventors: 高明岸上; 隆深川; 泰明湯田; 正幸星野
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2001-06-05
Filing date: 2001-06-05
Publication date: 2006-01-25
Anticipated expiration: 2021-06-05
Also published as: JP2002368663A

Description

【０００１】
【発明の属する技術分野】
本発明は、アレーアンテナを用いた方向及び角度広がり推定結果を基にアンテナ指向性を可変する適応アンテナ装置に関する。
【０００２】
【従来の技術】
複数のアンテナ素子からなるアレーアンテナを用いて、電波の到来方向推定を行う方法として、ＭＵＳＩＣ、ＥＳＰＲＩＴ、Ｃａｐｏｎ、フーリエ法がある。例えば、ＭＵＳＩＣ法に関しては、文献Ｒ．Ｏ．Ｓｃｈｍｉｄｔ、“ＭｕｌｔｉｐｌｅＥｍｉｔｔｅｒＬｏｃａｔｉｏｎａｎｄＳｉｇｎａｌＰａｒａｍｅｔｅｒＥｓｔｉｍａｔｉｏｎ”、ＩＥＥＥＴｒａｎｓ．，ＡＰ−３４，ｐｐ．２７６−２８０（１９８６）に記載されている。
【０００３】
また、到来波の角度広がりの推定法として、Ｎ．Ｓ．Ｍ．Ｓｈａｈ他、“ＭＵＳＩＣアルゴリズムを用いた到来方向と角度広がりの同時推定”、2000年電子情報通信学会通信ソサエティ大会B-1-31に記載されている。また、所望波および干渉波方向が既知の場合、所望波方向に指向性ビームを向け、干渉波方向にヌルを向けるビーム形成のアルゴリズムとして、ＤＣＭＰ法が一般的に知られている。
【０００４】
さらに、電波の到来方向推定結果を基にアンテナの指向性を適応的に変化させる方法として、特開２０００−２１６６２０が開示されている。以下、図９を用いてその動作説明を行う。まず、複数の受信アンテナ５０−１〜５０−Ｌと、これらの受信アンテナでより受信された高周波信号５１−１〜５１−Ｌをそれぞれ２分配する信号分配手段５２と、この信号分配手段５２により分配された一方の系統の高周波信号を用い、前記複数のアンテナ５０−１〜５０−Ｌで受信した受信信号の共分散行列を求めるとともにこれに基づき複数の到来波の方位測定を行い、この共分散行列と複数の到来波の方位情報とを出力するＭＵＳＩＣ法を用いた方位測定手段５３と、この方位測定手段５３における測定の結果得られた複数の到来波の方位情報により指定された一つの方位情報を保存する指定信号保存手段５４と、前記信号分配手段５２により分配された他方の系統の高周波信号を受信し、前記指定信号保存手段５４で保存された、指定された１つの方位以外の信号を抑圧させるための重み付けを前記共分散行列に基づき演算する重み付け演算回路５５と、前記重み付け演算回路５５で演算された重み付けにより前記複数の受信アンテナ５０−１〜５０−Ｌで受信された高周波信号５１−１〜５１−Ｌに重み付けを行う重み付け手段５６と、この重み付け手段より出力される高周波信号を合成して出力する信号合成手段５７とを含み、信号合成手段５７の出力を復調部５８により復調を行う。
【０００５】
【発明が解決しようとする課題】
従来は、推定された所望波の到来方向に対する指向性ビームを形成しているが、実際の伝搬環境下では、無線局周辺の建物などにより反射や回折の影響を受け、角度広がりをもって電波は到来する。所望波の到来波方向へ指向性ビームを向ける場合、角度広がりに応じた最適な指向性ビームの形成は従来考慮されていない。また、複数波が到来する環境下において、最適な到来波を選択する方法としては、最大電力波を選択するのが一般的であった。しかしながら、受信電力が大きくても、マルチパス波を多く含む電波を選択する可能性があった。
【０００６】
本発明は、角度広がり推定結果を用いて、指向性ビーム形成におけるビーム幅を可変にする。また、複数到来波が存在する場合は角度広がりの小さい到来波方向を選択し、この方向に指向性ビームをむけることで送受信品質改善を行う適応アンテナ装置を提供することを目的とする。さらには、干渉波方向に対しては、干渉波の角度広がりに応じたヌル幅のヌルを形成することで、到来方向推定誤差が含まれる場合でも、ロバストな干渉波抑圧が可能となる適応アンテナ装置を提供することを目的とする。
【０００７】
【課題を解決するための手段】
本発明によれば、受信部の出力信号を用いて最大電力を有する到来波の到来方向を推定する主波方向推定部と、前記最大電力を有する到来波の到来方向における角度広がりを推定する角度広がり推定部と、前記最大電力を有する到来波の到来方向に前記アレーアンテナの指向性を向け、さらにそのビーム幅は前記角度広がり推定部の推定結果を基に可変するアレーウエイトを生成するウエイト生成部により、所望波方向の角度広がりにより最適なビーム幅のアレーアンテナの指向性を形成することができる。
【０００８】
【発明の実施の形態】
本発明の請求項１に記載の発明は、複数のアンテナ素子で構成されるアレーアンテナと、前記アレーアンテナの各アンテナ素子で受信された到来波の信号を周波数変換後に直交検波する受信部と、前記受信部の出力信号を用いて最大電力を有する到来波の到来方向を推定する主波方向推定部と、前記主波方向推定部の出力を用いて前記最大電力を有する到来波の到来方向における角度広がりを推定する角度広がり推定部と、前記最大電力を有する到来波の到来方向に前記アレーアンテナの指向性を向け、さらにそのビーム幅は前記角度広がり推定部の推定結果を基に可変するアレーウエイトを生成するウエイト生成部と、前記受信部の出力信号に前記アレーウエイトを乗算し合成する受信ビーム形成部と、前記受信ビーム形成部の出力信号に対し復調処理を行う復調部とを有する適応アンテナ装置であり、主波方向に対する角度広がりに応じてメインローブのビーム幅を可変することができ、角度広がりが所定値よりも大きい場合、それらのマルチパスを含む主波方向から、狭ビームの指向性を向けることでマルチパス抑圧効果をさらに高めることができる作用を有する。
【０００９】
本発明の請求項２に記載の発明は、複数のアンテナ素子で構成されるアレーアンテナと、前記アレーアンテナの各アンテナ素子で受信された到来波の信号を周波数変換後に直交検波する受信部と、前記受信部の出力信号を用いて複数の到来波の到来方向及びそれらの電力を推定する到来方向推定部と、前記到来方向推定部の出力を用いて前記複数の到来波から最大電力波を選択し、前記複数の到来波のうち、前記最大電力波に対して所定値以内の電力の到来波に対し角度広がりを推定する角度広がり推定部と、前記最大電力波に対して所定値以内の電力の到来波が存在する場合には角度広がりが最小となる方向に、存在しない場合は前記最大電力波方向に、前記アレーアンテナの指向性を向けるアレーウエイトを生成するウエイト生成部と、前記受信部の出力信号に前記アレーウエイトを乗算し合成する受信ビーム形成部と、前記受信ビーム形成部の出力信号に対し復調処理を行う復調部とを有する適応アンテナ装置であって、前記ウエイト生成部が形成する指向性のビーム幅は、角度広がり推定部の推定結果を基に可変する適応アンテナ装置であり、角度広がりが最小である到来波の到来方向にメインビームを向けることが可能となり、受信電力的にも比較的良好で、かつ、角度広がりを構成する素波間の遅延分散が小さい到来波を選択的に受信することが可能になり、マルチパス抑圧効果を高めることで、受信品質を改善することができる作用を有する。
更に、到来波の角度広がりに応じてメインローブのビーム幅を可変した指向性パターンで送信することができ、通信を行うおうとする無線局以外に存在する無線局に対して干渉を十分に低減できる作用を有する。
【００１０】
本発明の請求項３に記載の発明は、複数のアンテナ素子で構成されるアレーアンテナと、前記アレーアンテナの各アンテナ素子で受信された到来波の信号を周波数変換後に直交検波する受信部と、前記受信部の出力信号を用いて最大電力を有する到来波の到来方向を推定する主波方向推定部と、前記主波方向推定部の出力を用いて前記最大電力を有する到来波の到来方向における角度広がりを推定する角度広がり推定部と、前記最大電力を有する到来波の到来方向に前記アレーアンテナの指向性を向け、さらにそのビーム幅は前記角度広がり推定部の推定結果を元に可変するアレーウエイトを生成するウエイト生成部と、送信信号に対し前記アレーウエイトを乗算する送信ビーム形成部と、前記送信ビーム形成部の出力を前記アレーアンテナから送信する送信部とを有する適応アンテナ装置であり、到来波の角度広がりに応じてメインローブのビーム幅を可変した指向性パターンで送信することができ、通信を行うおうとする無線局以外に存在する無線局に対して干渉を十分に低減できる作用を有する。
【００１１】
本発明の請求項４に記載の発明は、複数のアンテナ素子で構成されるアレーアンテナと、前記アレーアンテナの各アンテナ素子で受信された到来波の信号を周波数変換後に直交検波する受信部と、前記受信部の出力信号を用いて複数の到来波の到来方向及びそれらの電力を推定する到来方向推定部と、前記到来方向推定部の出力を用いて前記複数の到来波から最大電力波を選択し、前記複数の到来波のうち、前記最大電力波に対して所定値以内の電力の到来波に対し角度広がりを推定する角度広がり推定部と、前記最大電力波に対して所定値以内の電力の到来波が存在する場合は角度広がりが最小となる方向に、存在しない場合は前記最大電力波方向に、前記アレーアンテナの指向性を向けるアレーウエイトを生成するウエイト生成部と、送信信号に対し前記アレーウエイトを乗算する送信ビーム形成部と、前記送信ビーム形成部の出力を前記アレーアンテナから送信する送信部とを有する適応アンテナ装置であって、前記ウエイト生成部が形成する指向性のビーム幅は角度広がり推定部の推定結果を基に可変する適応アンテナ装置であり、通信を行うおうとする所望の無線局以外に存在する無線局に対して干渉を十分に低減でき、さらに複数の到来波が存在する場合は、受信電力的にも比較的良好で、かつ、角度広がりを構成する素波間の遅延分散が小さい到来方向を選択し、その方向に対し送信することが可能になり、これにより所望の無線局における受信品質を高めることができるができる作用を有する。
更に、到来波の角度広がりに応じてメインローブのビーム幅を可変した指向性パターンで送信することができ、通信を行うおうとする無線局以外に存在する無線局に対して干渉を十分に低減できる作用を有する。
【００１３】
本発明の請求項５に記載の発明は、ウエイト生成部は角度広がりが所定値より大きい場合、ビーム幅を狭めた指向性ビームを形成する請求項１ないし４のいずれか記載の適応アンテナ装置であり、到来波の角度広がりに応じてメインローブのビーム幅を可変した指向性パターンで送受信することができる作用を有する。
【００１４】
本発明の請求項６に記載の発明は、複数のアンテナ素子で構成されるアレーアンテナと、前記アレーアンテナの各アンテナ素子で受信された到来波の信号を周波数変換後に直交検波する受信部と、前記受信部の出力信号を用いて最大電力を有する到来波の到来方向を推定する主波方向推定部と、前記受信部の出力信号を用いて干渉波の到来方向を推定する干渉波到来方向推定部と、前記干渉波到来方向推定部の出力を用いて前記干渉波の到来方向の角度広がりを推定する干渉波角度広がり推定部と、前記最大電力を有する到来波の到来方向に前記アレーアンテナの指向性を向け、前記最大電力を有する到来波の方向と前記干渉波の到来方向が同一でない場合、前記干渉波の到来方向に、干渉波角度広がりに応じた幅の指向性のヌルを形成するアレーウエイトを生成するウエイト生成部と、前記受信部の出力信号に前記アレーウエイトを乗算し合成する受信ビーム形成部と、前記受信ビーム形成部の出力信号に対し復調処理を行う復調部とを有する適応アンテナ装置であり、干渉波の角度広がりに応じたヌル幅を形成することができ、到来方向推定に誤差が含まれる場合でも、干渉波の抑圧効果の高い指向性が形成されることで、受信品質の改善ができる作用を有する。
【００１５】
本発明の請求項７に記載の発明は、複数のアンテナ素子で構成されるアレーアンテナと、前記アレーアンテナの各アンテナ素子で受信された到来波の信号を周波数変換後に直交検波する受信部と、前記受信部の出力信号を用いて複数の到来波の到来方向及びそれらの電力を推定する到来方向推定部と、前記到来方向推定部の出力を用いて前記複数の到来波から最大電力波を選択し、前記複数の到来波のうち、前記最大電力波に対して電力が所定値以内の到来波に対し角度広がりを推定する角度広がり推定部と、前記受信部の出力信号を用いて干渉波の到来方向を推定する干渉波到来方向推定部と、前記干渉波到来方向推定部の出力を用いて前記干渉波の到来方向の角度広がりを推定する干渉波角度広がり推定部と、前記最大電力波に対し到来波電力が所定値以内の到来波が存在する場合には角度広がりが最小となる方向に、存在しない場合は前記最大電力波方向に、前記アレーアンテナの指向性を向け、前記アレーアンテナの指向性を向けた方向と前記干渉波の到来方向が同一でない場合、前記干渉波の到来方向に、干渉波角度広がりに応じた幅の指向性のヌルを形成するアレーウエイトを生成するウエイト生成部と、前記受信部の出力信号に前記アレーウエイトを乗算し合成する受信ビーム形成部と、前記受信ビーム形成部の出力信号に対し復調処理を行う復調部とを有する適応アンテナ装置であり、干渉波の角度広がりに応じたヌル幅を形成することができ、到来方向推定に誤差が含まれる場合でも、干渉波の抑圧効果の高い指向性が形成されることで、受信品質の改善ができる作用を有する。
【００１６】
本発明の請求項８に記載の発明は、複数のアンテナ素子で構成されるアレーアンテナと、前記アレーアンテナの各アンテナ素子で受信された到来波の信号を周波数変換後に直交検波する受信部と、前記受信部の出力信号を用いて最大電力を有する到来波の到来方向を推定する主波方向推定部と、前記受信部の出力信号を用いて干渉波到来方向を推定する干渉波到来方向推定部と、前記干渉波到来方向推定部の出力を用いて前記干渉波到来方向の角度広がりを推定する干渉波角度広がり推定部と、前記最大電力を有する到来波の到来方向に前記アレーアンテナの指向性を向け、前記最大電力を有する到来波の方向と前記干渉波の到来方向が同一でない場合、前記干渉波の到来方向に、干渉波角度広がりに応じた幅の指向性のヌルを形成するアレーウエイトを生成するウエイト生成部と、送信信号に対し
前記アレーウエイトを乗算する送信ビーム形成部と、前記送信ビーム形成部の出力を前記アレーアンテナから送信する送信部とを有する適応アンテナ装置であり、干渉波の角度広がりに応じたヌル幅を形成することができ、到来方向推定に誤差が含まれる場合でも、干渉波の抑圧効果の高い指向性が形成されることで、送信時の通信品質の改善ができる作用を有する。
【００１７】
本発明の請求項９に記載の発明は、複数のアンテナ素子で構成されるアレーアンテナと、前記アレーアンテナの各アンテナ素子で受信された到来波の信号を周波数変換後に直交検波する受信部と、前記受信部の出力信号を用いて複数の到来波の到来方向及びそれらの電力を推定する到来方向推定部と、前記到来方向推定部の出力を用いて前記複数の到来波から最大電力波を選択し、前記複数の到来波のうち、前記最大電力波に対して電力が所定値以内の到来波に対し角度広がりを推定する角度広がり推定部と、前記受信部の出力信号を用いて干渉波の到来方向を推定する干渉波到来方向推定部と、前記干渉波到来方向推定部の出力を用いて前記干渉波の到来方向の角度広がりを推定する干渉波角度広がり推定部と、前記最大電力波に対し到来波電力が所定値以内の到来波が存在する場合には角度広がりが最小となる方向に、存在しない場合は前記最大電力波方向に、前記アレーアンテナの指向性を向け、前記アレーアンテナの指向性を向けた方向と前記干渉波の到来方向が同一でない場合、前記干渉波の到来方向に、干渉波角度広がりに応じた幅の指向性のヌルを形成するアレーウエイトを生成するウエイト生成部と、送信信号に対し前記アレーウエイトを乗算する送信ビーム形成部と、前記送信ビーム形成部の出力を前記アレーアンテナから送信する送信部とを有する適応アンテナ装置であり、干渉波の角度広がりに応じたヌル幅を形成することができ、到来方向推定に誤差が含まれる場合でも、干渉波の抑圧効果の高い指向性が形成されることで、送信時の通信品質の改善ができる作用を有する。
【００１８】
本発明の請求項１０に記載の発明は、到来波の角度広がりの大きさにより、主波方向推定部における到来方向推定アルゴリズムを切り替える請求項１又は３記載の適応アンテナ装置であり、角度広がりに応じた最適な到来方向推定の選択が可能で推定精度の向上が得られる作用を有する。
【００１９】
本発明の請求項１１に記載の発明は、到来波の角度広がりの大きさにより、到来方向推定部における到来方向推定アルゴリズムを切り替える請求項２、４、７又は９記載の適応アンテナ装置であり、角度広がりに応じた最適な到来方向推定の選択が可能で推定精度の向上が得られる作用を有する。
【００２０】
本発明の請求項１２に記載の発明は、干渉波の角度広がりの大きさにより、干渉波到来方向推定部における到来方向推定アルゴリズムを切り替える請求項６ないし９のいずれか記載の適応アンテナ装置であり、角度広がりに応じた最適な到来方向推定の選択が可能で推定精度の向上が得られる作用を有する。
【００２１】
本発明の請求項１３に記載の発明は、角度広がりが予め決められた値より大きい場合に、到来方向推定アルゴリズムを空間スムージング処理を加えたアルゴリズムに切り替える請求項１０、１１又は１２記載の適応アンテナ装置であり、角度広がりに応じた最適な到来方向推定の選択が可能で推定精度の向上が得られる作用を有する。
【００２２】
以下、本発明の実施の形態について、図面を用いて説明する。
【００２３】
（実施の形態１）
図１は適応アンテナ装置の構成を示すブロック図である。以下図１を用いてその動作説明を行う。アレーアンテナ１はＭ個（ただし、Ｍ＞１）のアンテナ素子１−１〜１−Ｍから構成される。各アンテナ素子１−１〜１−Ｍで受信した高周波信号２−１〜２−Ｍは、各アンテナ素子１−１〜１−Ｍに接続された受信部３−１〜３−Ｍにおいて周波数変換された後に直交復調され、直交するＩ、Ｑ信号からなる受信信号４−１〜４−Ｍに変換される。各受信信号４−１〜４−Ｍは２分配され、一方は主波方向推定部５、もう一方は受信ビーム形成部８に入力される。
【００２４】
主波方向推定部５は最大電力を有する到来波の到来方向を推定する。以下、その動作を説明する。なお、以下では、Ｉ信号及びＱ信号のそれぞれに対しサンプリングされた信号を用い、Ｉ信号を実数部、Ｑ信号を虚数部として表現される複素ディジタル信号を受信信号ｘ（ｋ）と表す。まず、受信信号４−１〜４−Ｍからそれぞれ得られるサンプル時刻ｋΔＴ（ただし、ｋは自然数、ΔＴはサンプリング間隔）における受信信号ｘ₁（ｋ）、ｘ₂（ｋ）、．．．、ｘ_M（ｋ）から（数１）で示される受信ベクトルｘ（ｋ）を構成し、さらに、所定Ｎサンプル期間毎に蓄積した受信ベクトルｘ（ｋ）を用いて（数２）の相関行列Ｒを求める。この場合、相関行列Ｒは（Ｍ×Ｍ）行列となる。
【００２５】
【数１】

【００２６】
【数２】

【００２７】
次に、Ｃａｐｏｎ法による到来角評価関数を用いて、所定の角度ステップΔθ毎に到来角評価を行う。到来角評価関数は、文献Ｊ．Ｃａｐｏｎ，“Ｈｉｇｈ−ＲｅｓｏｌｕｔｉｏｎＦｒｅｑｕｅｎｃｙ−ＷａｖｅｎｕｍｂｅｒＳｐｅｃｔｒｕｍＡｎａｌｙｓｉｓ.”Ｐｒｏｃ．ＩＥＥＥ，５７（８）、ｐｐ．１４０８−１４１８、１９６９に記載されており、（数３）で示される。
【００２８】
【数３】

【００２９】
ただし、ａ（θ）は、方位θに対するアレーアンテナの複素応答を表す。（以下、アレーモードベクトルと呼ぶ）また、Ｒ^-1はＲの逆行列である。
【００３０】
到来角評価の結果の角度スペクトラムには、いくつかの極大値が得られるが、その中の最大のピークを最大電力波とし、最大ピークを与える角度を主波方向θ₀とする。
【００３１】
次に、角度広がり推定部６における動作を以下説明する。
【００３２】
主波方向推定部５から得られた主波方向θ₀における角度広がりを（数４）で示される角度広がり評価関数を用いて、角度広がりパラメータδを所定の角度ステップΔδ毎に評価を行う。
【００３３】
【数４】

【００３４】
ただし、ａ_x（θ）は、アレーモードベクトルａ（θ）に対し、複素領域の引数をとるように拡張した一般化アレーモードベクトルである。（数４）における角度広がりパラメータδを可変して得られる角度広がりスペクトラムに対し、最大ピークを与える角度広がり値δ₀を推定値とする。
【００３５】
なお、ここでは、Ｃａｐｏｎ法に対し、一般化アレーモードベクトルを用いて角度広がりを推定しているが、ＭＵＳＩＣ法、ＥＳＩＰＲＩＴ法と同様に一般化アレーモードベクトルを適用して角度広がり推定を行っても同様である。
【００３６】
ウエイト生成部７は、主波方向推定値θ₀と、その角度広がり推定値δ₀を用いて、メインビーム方向をθ₀に、そのビーム幅をδ₀に応じた指向性をもつアレーウエイトを生成する。以下では、ドルフ−チェビシェフ指向性合成法を用いた場合の動作説明を行う。ドルフ−チェビシェフ指向性合成法はアンテナの指向性がチェビシェフ多項式と一致するように励振分布を決定することで、メインローブに対するサイドローブ抑圧値ＳＬＬを任意に設定することができ、サイドローブ抑圧値ＳＬＬを小さくすることで、そのメインローブのビーム幅が狭くなる関係を有している。詳細については、例えば、Ｗ．Ｌ．Ｓｔｕｚｍａｎ他「ＡｎｔｅｎｎａＴｈｅｏｒｙａｎｄＤｅｓｉｇｎ」、Ｗｉｌｅｙ、１９８１、ｐｐ．５３７〜５４２に記載されている。ここでは、８素子の直線アレーアンテナを用いた場合について、以下概略を示す。８素子（Ｍ＝８）の場合、メインローブ方向がθ₀で、サイドローブ抑圧値ＳＬＬであるアレーウエイトは（数５）で示される。
【００３７】
【数５】

【００３８】
ここで、ｓ_mは以下の（数６）から（数１０）で与えられる。
【００３９】
【数６】

【００４０】
【数７】

【００４１】
【数８】

【００４２】
【数９】

【００４３】
【数１０】

【００４４】
ただし、ｍ＝１〜８、λはキャリアの波長、ｄはアレー素子間隔である。
【００４５】
ここで、ウエイト生成部７は角度広がりが所定値Ａ１より大きい場合、ビーム幅を狭めた指向性ビームを形成する。例えばＡ１＝１０°と設定し、δ₀≦１０°であれば、ＳＬＬ＝２０ｄＢにし、δ₀＞１０°であれば、ＳＬＬ＝１０ｄＢと設定することで、ウエイト生成部７は角度広がりが所定値Ａ１より大きい場合、ビーム幅を狭めた指向性ビームを形成することができる。
【００４６】
受信ビーム形成部８は、ウエイト生成部７でえられたアレーウエイトを用いて、受信信号に乗算し合成する。すなわち、（数１１）に示すように受信信号ｘ_m（ｋ）に対し、合成信号ｙ（ｋ）を出力する。ただし、＊は複素共役を示す。
【００４７】
【数１１】

【００４８】
復調部９は、受信ビーム形成部８による合成信号ｙ（ｋ）に対し復調処理を行い、復号データを出力する。
【００４９】
以上のように本実施の形態では、ウエイト生成部７で主波方向に対する角度広がりに応じてメインローブのビーム幅を可変することができる。角度広がりが大きい場合には、角度広がりを構成する素波間の時間的な分散も大きくなるため、角度広がりが所定値よりも大きい場合、それらのマルチパスを含む主波方向から、狭ビームの指向性を向けることでマルチパス抑圧効果をさらに高めることができ、受信品質を高めることができる。
【００５０】
（実施の形態２）
図２は適応アンテナ装置の構成を示すブロック図である。以下図２を用いてその動作説明を行う。アレーアンテナはＭ個（ただし、Ｍ＞１）のアンテナ素子１−１〜１−Ｍから構成される。各アンテナ素子１−１〜１−Ｍで受信した高周波信号２−１〜２−Ｍは、各アンテナ素子１−１〜１−Ｍに接続された受信部３−１〜３−Ｍにおいて周波数変換された後に直交復調され、直交するＩ、Ｑ信号からなる受信信号４−１〜４−Ｍに変換される。各受信信号４−１〜４−Ｍは２分配され、一方は到来方向推定部１０、もう一方は受信ビーム形成部８に入力される。
【００５１】
到来方向推定部１０は受信部の出力信号を用いて複数の到来波の到来方向及びそれらの電力を推定する。以下に、その動作を説明する。なお、以下では、Ｉ信号及びＱ信号のそれぞれに対しサンプリングされた信号を用い、Ｉ信号を実数部、Ｑ信号を虚数部として表現される複素ディジタル信号を受信信号ｘ（ｋ）と表す。まず、受信信号４―１〜Ｍからそれぞれ得られるサンプル時刻ｋΔＴ（ただし、ｋは自然数、ΔＴはサンプリング間隔）における受信信号ｘ₁（ｋ）、ｘ₂（ｋ）、．．．、ｘ_M（ｋ）から（数１）で示される受信ベクトルｘ（ｋ）を構成し、さらに、所定Ｎサンプル期間毎に蓄積した受信ベクトルｘ（ｋ）を用いて（数２）の相関行列Ｒを求める。この場合、相関行列Ｒは（Ｍ×Ｍ）行列となる。次に、ＭＵＳＩＣ法による到来角評価関数を用いて、所定の角度ステップΔθ毎に到来角評価を行う。到来角評価関数は、（数１２）で示される。
【００５２】
【数１２】

【００５３】
ここで、Ｅ_Nは雑音空間行列であり以下のように求める。到来波数がＳ個の場合、相関行列Ｒの固有値分解して得られる固有値λ₁〜λ_Mは降順に並べた時、（数１３）の関係にあり、雑音固有ベクトル空間に属する（Ｍ−Ｓ）個の相関行列Ｒの固有ベクトルｅ_sを列ベクトルとするＥ_N＝[ｅ_s+1、．．．、ｅ_M] が雑音固有空間行列を形成する。
【００５４】
【数１３】

【００５５】
なお、一般に到来波数Ｓは未知であるため、到来波数を判定のため固有値の分布や文献Ｍ．ＷａｘａｎｄＴ．Ｋａｉｌａｔｈ，“ＤｅｔｅｃｔｉｏｎｏｆＳｉｇｎａｌｓｂｙＩｎｆｏｒｍａｔｉｏｎＴｈｅｏｒｅｔｉｃＣｒｉｔｅｒｉａ”，ＩＥＥＥＴｒａｎｓ．ＯｎＡｃｏｕｓｔｉｃｓ，ＳｐｅｅｃｈａｎｄＳｉｇｎａｌＰｒｏｃｅｓｓｉｎｇ，Ｖｏｌ．ＡＳＳＰ３３（２），ｐｐ．３８７−３９２，Ｆｅｂｒｕａｒｙ（１９８５）に記載されている信号個数判定基準を設け判定を行う。また、到来角評価の結果、得られる角度スペクトラムには、いくつかの極大値が得られるが、その中の最大のピークを最大電力波とし、最大ピークを与える角度を主波方向θ₀とし、残りの（Ｓ−１）個のピーク方向を大きい順にサーチし、それぞれの到来方向をθ_nとする。ただし、ｎ＝１、...、Ｓ−１とする。それぞれの到来方向に対する受信電力を（数１４）を用いて推定する。ただし、ｎ＝０、...、Ｓ−１であり、ＩはＭ×Ｍの単位行列である。
【００５６】
【数１４】

【００５７】
角度広がり推定部１１は、到来方向推定部１０で得られた複数の到来方向とその電力推定値から、最大電力波と、最大電力波に対し到来波電力が所定値Ｌｐ内の到来波に対し角度広がりを推定する。すなわち、｜Ｐ（θ_n）―Ｐ（θ₀）｜≦Ｌ_pを満たすθ_vに対してのみ（数１５）を用いて到来方向の角度広がり推定を行う。ただし、ｎ＝１、...、Ｓ−１である。
【００５８】
【数１５】

【００５９】
ただし、ａ_x（θ）は、アレーモードベクトルに対し、複素領域の引数をとるように拡張した一般化アレーモードベクトルである。（数１５）における角度広がりパラメータδを所定の角度ステップΔδ毎に評価して得られる角度広がりスペクトラムに対し、最大ピークを与える角度広がり値δ₀を到来方向θｖに対する角度広がり推定値δｖ₀とする。
【００６０】
なお、ここでは、ＭＵＳＩＣ法を用いて到来方向推定、角度広がり推定を行っているが、ＥＳＩＰＲＩＴ法等を用いても同様に推定が可能である。
【００６１】
ウエイト生成部１２は、角度広がりが推定された到来波が複数ある場合は、角度広がりが最小となる方向にアレーアンテナメインビームを向けるアレーウエイトを生成する。角度広がりが推定された到来波が一つである場合は、その到来方向にメインビームを向ける。アレーウエイトｗｋとしては、実施の形態１で説明したドルフ−チェビシェフ指向性合成法などが適用できる。
【００６２】
受信ビーム形成部８は、ウエイト生成部１２で生成したアレーウエイトｗｋを用いて、受信信号に乗算し合成する。すなわち、（数１１）に示すように受信信号ｘ_m（ｋ）に対し、合成信号ｙ（ｋ）を出力する。ただし、＊は複素共役を示す。
【００６３】
復調部９は、受信ビーム形成部８による合成信号ｙ（ｋ）に対し復調処理を行い、復号データを出力する。
【００６４】
以上のように本実施の形態では、到来方向推定部１０と角度広がり推定部１１において、最大電力波に対し到来波電力が所定値内の到来波が複数存在する場合、それらの到来波のうち、角度広がりが最小である到来波の到来方向にメインビームを向けることが可能となり、受信電力的にも比較的良好で、かつ、角度広がりを構成する素波間の遅延分散が小さい到来波を選択的に受信することが可能になり、マルチパス抑圧効果を高めることで、受信品質を改善することができる。
【００６５】
なお、本実施例では、角度広がりに対するメインビームの幅については、特に説明を加えていなかったが、実施の形態１で説明したように、角度広がり推定値に応じてビーム幅を可変する構成でもよい。この場合は上述した効果に加え、実施の形態１で説明した効果が加わる。
【００６６】
（実施の形態３）
図３は適応アンテナ装置の構成を示すブロック図である。以下図３を用いてその動作説明を行う。アレーアンテナはＭ個（ただし、Ｍ＞１）のアンテナ素子１−１〜１−Ｍから構成される。各アンテナ素子１−１〜１−Ｍで受信した高周波信号２−１〜２−Ｍは、各アンテナ素子１−１〜１−Ｍに接続された受信部３−１〜３−Ｍにおいて周波数変換された後に直交復調され、直交するＩ、Ｑ信号からなる受信信号４−１〜４−Ｍに変換され、主波方向推定部５に入力される。
【００６７】
受信部３の出力信号４を用いて最大電力を有する到来波の到来方向を推定する主波方向推定部５と、最大電力を有する到来波の到来方向における角度広がりを推定する角度広がり推定部６と、最大電力を有する到来波の到来方向にアレーアンテナの指向性を向け、さらにそのビーム幅は角度広がり推定部６の推定結果を基に可変するアレーウエイトを生成するウエイト生成部７の動作は実施の形態１と同様であり、その説明は省略する。
【００６８】
変調部２０は、入力される送信データを変調してベースバンドＩ信号Ｉ（ｋ）及びＱ信号Ｑ（ｋ）を生成する。送信ビーム形成部２１は、変調されたベースバンドＩ信号Ｉ（ｋ）及びＱ信号Ｑ（ｋ）を送信するアレー素子数Ｍに等しい数で分配し、それぞれに対し、アレーウエイトｗｍを乗算する。（ｍ＝１，．．．，Ｍ）すなわち、第ｍ番目の送信部への入力信号ｚｍ（ｋ）＝ｗｍ×（Ｉ（ｋ）＋ｊＱ（ｋ））となる。ただし、ｍ＝１〜Ｍとする。
【００６９】
送信部２２−１〜２２−Ｍは、入力されたベースバンド信号ｚｍ（ｋ）をＲＦ送信周波数に変換し、規定の送信電力によりアレーアンテナの各アレー素子から送信する。
【００７０】
以上のように本実施の形態では、アレーアンテナ１で受信した信号から電波の到来方向を推定し、さらにその到来波方向にメインローブを向け、さらに到来波の角度広がりに応じてメインローブのビーム幅を可変した指向性パターンで送信することができる。これにより、通信を行うおうとする無線局以外に存在する無線局に対して干渉を十分に低減でき、さらに角度広がりが大きい場合には、角度広がりを構成する素波間の時間的な分散も大きくなるため、角度広がりが所定値よりも大きい場合、それらのマルチパスを含む主波方向から、狭ビームの指向性を向けることでマルチパス抑圧効果をさらに高めることができ、これにより所望の無線局における受信品質を高めることができる。
【００７１】
（実施の形態４）
図４は適応アンテナ装置の構成を示すブロック図である。以下図４を用いてその動作説明を行う。アレーアンテナはＭ個（ただし、Ｍ＞１）のアンテナ素子１−１〜１−Ｍから構成される。各アンテナ素子１−１〜１−Ｍで受信した高周波信号２−１〜２−Ｍは、各アンテナ素子１−１〜１−Ｍに接続された受信部３−１〜３−Ｍにおいて周波数変換された後に直交復調され、直交するＩ、Ｑ信号からなる受信信号４−１〜４−Ｍに変換され、到来方向推定部１０に入力される。
【００７２】
受信部３−１〜３−Ｍの出力信号４−１〜４−Ｍを用いて複数の到来波の到来方向及びそれらの電力を推定する到来方向推定部１０と、複数の到来方向うち、最大電力波と、最大電力波に対し到来波電力が所定値内の到来波に対し角度広がりを推定する角度広がり推定部１１と、最大電力波に対し到来波電力が所定値内の到来波が存在する場合、角度広がりが最小となる方向に、存在しない場合は前記最大電力波方向に、アレーアンテナの指向性を向けるアレーウエイトを生成するウエイト生成部１２は実施の形態２と同様であり、その説明は省略する。
【００７３】
送信ビーム形成部２１は送信データを変調部２０において、変調されたベースバンドＩ信号Ｉ（ｋ）及びＱ信号Ｑ（ｋ）を送信するアレー素子数に等しい数で分配し、それぞれに対し、アレーウエイトｗｋを乗算する。すなわち、第ｍ番目の送信部２２への入力信号ｚｍ（ｋ）＝ｗｍ×（Ｉ（ｋ）＋ｊＱ（ｋ））となる。ただし、ｍ＝１〜Ｍである。
【００７４】
送信部２２−１〜２２−Ｍは、入力されたベースバンド信号ｚｍ（ｋ）をＲＦ送信周波数に変換し、規定の送信電力によりアレーアンテナの各アレー素子から送信する。
【００７５】
以上のように本実施の形態では、アレーアンテナで受信した信号から電波の到来方向を推定し、その到来波方向にメインローブを向け、さらに到来波の角度広がりに応じてメインローブのビーム幅を可変した指向性パターンで送信することができる。これにより、通信を行うおうとする所望の無線局以外に存在する無線局に対して干渉を十分に低減でき、さらに複数の到来波が存在する場合は、受信電力的にも比較的良好で、かつ、角度広がりを構成する素波間の遅延分散が小さい到来方向を選択し、その方向に対し送信することが可能になり、これにより所望の無線局における受信品質を高めることができる。
【００７６】
（実施の形態５）
図５は適応アンテナ装置の構成を示すブロック図である。以下図５を用いてその動作説明を行う。図５では、第１の実施の形態における適応アンテナ装置の構成を示す図１おいて、角度広がり推定部６をなくし、干渉波到来方向推定部３１と干渉波角度広がり推定部３２が追加された構成になっており、干渉波を抑圧するアレーウエイトを生成するものである。以下異なる部分について主に説明する。
【００７７】
アレーアンテナ１および受信部３によって、受信信号４が得られるまでの動作は上述した第１の実施の形態と同様である。主波方向推定部５は、第１の実施の形態における動作によって、受信部３からの出力信号４を用いて最大電力を有する到来波の到来方向を推定する。
【００７８】
干渉波到来方向推定部３１は、受信部３の出力信号４を用いて、干渉波の到来方向を推定する。ここで、干渉波とは、ＴＤＭＡ、ＦＤＭＡの場合では、後続する復調部９における等化器で等化できない程度の遅延時間の到来波、あるいは、他セルからの干渉波であり、ＣＤＭＡの場合、異なる符合に割り当てられたユーザを想定している。ＩＭＴ−２０００におけるＤＳ−ＣＤＭＡ方式の場合、高速データ通信を行うユーザと低速データ通信あるいは音声ユーザが混在する環境下での通信が想定され、特に高速データ通信を行うユーザに対しては送信電力も増加するため、他ユーザへの干渉度が増加する。
【００７９】
以下では、ＣＤＭＡ方式の基地局として本実施の形態を適用した場合の動作説明する。干渉波到来方向推定部３１では、受信信号４を用いて、他ユーザに割り当てられた符号により逆拡散を行う。逆拡散された受信信号のＩ信号及びＱ信号のそれぞれに対しサンプリングされた信号を用い、Ｉ信号を実数部、Ｑ信号を虚数部として表現される複素ディジタル信号を受信信号ｈ（ｔ）と表す。逆拡散後の受信信号からそれぞれ得られるサンプル時刻ｋΔＴ（ただし、ｋは自然数、ΔＴはサンプリング間隔）における受信信号ｈ₁（ｋ）、ｈ₂（ｋ）、．．．、ｈ_M（ｋ）から（数１６）で示される受信ベクトルｈ（ｋ）を構成し、さらに、所定Ｎサンプル期間毎に蓄積した受信ベクトルｈ（ｋ）を用いて（数１７）の相関行列Ｒ_hを求める。この場合、相関行列Ｒ_hは（Ｍ×Ｍ）行列となる。
【００８０】
【数１６】

【００８１】
【数１７】

【００８２】
次に、Ｃａｐｏｎ法による到来角評価関数を用いて、所定の角度ステップΔφ毎に到来角評価を行う。到来角評価関数は、（数１８）で示される。
【００８３】
【数１８】

【００８４】
到来角評価の結果の角度スペクトラムには、いくつかの極大値が得られるが、その中の最大のピークを最大電力波とし、最大ピークを与える角度を干渉波方向φ₀とする。
【００８５】
次に、干渉波角度広がり推定部３２における動作を以下説明する。干渉波到来方向推定部３１から得られた主波方向φ₀における角度広がりを（数１９）で示される角度広がり評価関数を用いて、角度広がりパラメータψを所定の角度ステップΔψ毎に評価を行う。
【００８６】
【数１９】

【００８７】
（数１９）における角度広がりパラメータψを可変して得られる角度広がりスペクトラムに対し、最大ピークを与える角度広がり値ψ₀を推定値とする。なお、ここでは、Ｃａｐｏｎ法に対し、一般化アレーモードベクトルを用いて角度広がりを推定しているが、ＭＵＳＩＣ法、ＥＳＩＰＲＩＴ法に同様に一般化アレーモードベクトルを適用して角度広がり推定を行っても同様のである。
【００８８】
ウエイト生成部３０は、到来方向にアレーアンテナの指向性を向け、到来方向と干渉波方向が同一でない場合、干渉波方向に干渉波角度広がりに応じた幅の指向性のヌルを形成するアレーウエイトを生成する。所望波方向と干渉波方向が既知である場合のアレーウエイト形成法としてはＤＣＭＰ法が代表的である。ＤＣＭＰ法の詳細は、Ｋ．Ｔａｋａｎｏ、“ＡｎＡｄａｐｔｉｖｅＡｒｒａｙＵｎｄｅｒＤｉｒｅｃｔｉｏｎａｌＣｏｎｓｔｒａｉｎｔ”、ＩＥＥＥＴｒａｎｓ．ＡＰ−２４（５）、１９７６に記載されている。拘束行列Ｃは、（数２０）で示すように到来方向θ₀のアレーモードベクトルａ（θ₀）、干渉波方向φ₀のアレーモードベクトルａ（φ₀）、さらに、ヌル幅を干渉波方向の角度広がりに応じたものにするため、角度広がりに応じた干渉波方向近傍のアレーモードベクトルａ（φ₀―αψ₀）、ａ（φ₀＋αψ₀）からなる。ただし、αは定数。また、拘束応答ベクトルＨは（数２１）で示される。ただし、Ｔは行列転置を表す。ＤＣＭＰ法によって得られる最適ウエイトＷｏｐｔは（数２２）で示される。Ｗｏｐｔをアレーウエイトとすることで、到来方向にアレーアンテナの指向性を向け、到来方向と干渉波方向が同一でない場合、干渉波方向に干渉波角度広がりに応じた幅の指向性のヌルを形成するアレーウエイトを生成することができる。なお、拘束行列Ｃ及び拘束応答ベクトルＨとして、（数２０）及び（数２１）の代わりに、（数２３）及び（数２４）を用いることで、拘束条件数を４から３に減らすことができ、アレー素子数が少ない場合、計算量の低減とアレー素子数が少ない場合への適用が可能となる。
【００８９】
【数２０】

【００９０】
【数２１】

【００９１】
【数２２】

【００９２】
【数２３】

【００９３】
【数２４】

【００９４】
以上のように得られたアレーウエイトを用いて、受信ビーム形成または送信ビーム形成に用いることで、干渉波の角度広がりに応じたヌル幅を形成することができ、到来方向推定に誤差が含まれる場合でも、干渉波の抑圧効果の高い指向性が形成されることで、受信または送信時の通信品質の改善が図れる。
【００９５】
なお、本実施の形態における主波方向推定部５の代わりに、第２の実施の形態で説明した到来方向推定部１０と角度広がり推定部１１を用いて、最大電力波に対し到来波電力が所定値内の到来波が複数存在する場合、それらの到来波のうち、角度広がりが最小である到来波の到来方向にメインビームを向ける構成でもよい。
【００９６】
なお、第３の実施の形態に、本実施の形態の干渉波到来方向推定部３１と干渉波角度広がり推定部３２を用いても良く、その場合の構成は図６のようになり、干渉波到来方向推定部３１と干渉波角度広がり推定部３２の動作は本実施の形態と同じで、その他の動作は第３の実施の形態と同様であり、本実施の形態と同様の効果が得られる。またこの場合も、主波方向推定部５の代わりに、第４の実施の形態で説明した到来方向推定部１０と角度広がり推定部１１を用いても良い。
【００９７】
（実施の形態６）
図７は適応アンテナ装置の別な構成を示すブロック図である。以下図７において、角度広がり推定部４１の推定結果を主波方向推定部４０にフィードバックしており、この情報を用いて主波方向推定部４０における方向推定アルゴリズムを切り替える動作を行う機能が追加されている。以下では、主に異なる部分である主波方向推定部４０の動作を図８のフローチャートを用いて説明を行う。
【００９８】
アレーアンテナ１および受信部３によって、受信信号４が得られるまでの動作は上述した第１の実施の形態と同様である（ｓ７０）。主波方向推定部４０はまず、受信信号４に対し、第１の到来方向推定処理により到来方向を推定する（ｓ７１）。ここで第１の到来方向推定処理は（数２）で示された相関行列演算（ｓ７１−１）後に、（数３）あるいは（数１２）で示される到来方向推定評価関数演算（ｓ７１−２）を行う。得られた到来方向推定結果を角度広がり推定部４１に入力し、角度広がり推定値を得る（ｓ７２）。得られた角度広がり値φと所定値ＡＳとの比較を行い（ｓ７３）、φ≦ＡＳである場合、その時の到来方向推定値を最終的な推定値とする（ｓ７４）。一方、φ＞ＡＳである場合、第２の到来方向推定処理を行う（ｓ７５）。ここで、第２の到来方向推定処理は、（数２）で示された相関行列演算（ｓ７５−１）後に、得られた相関行列に対しサブアレー素子数Ｍｓによる空間スムージング処理を更に行い（ｓ７５−２）、それにより得られた相関行列Ｒｓを用いて、（数３）あるいは（数１２）で示される到来方向推定評価関数演算を行う（ｓ７５−３）。ただし、Ｍｓ≦Ｍである。これにより得られた到来方向推定値を最終的な推定値とする（ｓ７４）。なお、空間スムージング処理に関しての詳細は、文献Pillai et al, "Forward/Backward Spatial Smoothing Techniques for Coherent Signal Identification", IEEE Trans. on Acoustics, speech and signal processing, VOL.37, NO.1, 1989等に記載されている。
【００９９】
以上のように本実施の形態では、角度広がりの大きさにより、主波方向推定部４０における到来方向推定アルゴリズムを切り替えることが可能となる。すなわち、角度広がりが所定値より大きい場合、主波方向推定部４０における到来方向推定アルゴリズムは空間スムージング処理を加えたアルゴリズムに切り替わる。角度広がりが１０度を超える大きさになると、角度広がりを構成する素波間が相関性の高いマルチパスとして見えるようになるため、相関行列のランクが低下し、到来波を高精度に推定できなくなる。そのため、本実施の形態で示したように空間スムージングを加えた到来方向推定処理を行うことで推定精度の改善が可能となる。逆に角度広がりが十分小さい領域では、空間スムージング処理時のアレーアンテナのサブアレー化によるアレー開口面が小さくなることによる推定精度の劣化を防ぐことができる。
【０１００】
なお、本発明を実施の形態３で説明した主波方向推定部に対しても同様に角度広がりに応じて到来方向推定アルゴリズムを切り替えてもよい。
【０１０１】
なお、本発明を実施の形態２、４及び５で説明した到来方向推定部に対しても同様に角度広がりに応じて到来方向推定アルゴリズムを切り替えてもよい。
【０１０２】
なお、本発明を実施の形態５で説明した干渉波到来方向推定部に対しても同様に角度広がりに応じて到来方向推定アルゴリズムを切り替えてもよい。
【０１０３】
【発明の効果】
以上のように本発明によれば、到来方向推定と角度広がり推定結果に応じて受信時あるいは送信時のアレーアンテナの指向性を、無線局の位置に対し、適応的にビーム方向とビーム幅を可変することができる。さらに、干渉局が存在する場合は、干渉波方向にヌルを形成することができ、そのヌル幅を角度広がりに応じて可変することができる。これらにより、本発明を複数の端末局と通信を行う必要のある移動体通信の基地局に適応することで、端末間の干渉低減ができ、通信品質の改善及びシステム容量の向上を行うことができる。
【図面の簡単な説明】
【図１】本発明の実施の形態１における適応アンテナ装置の構成を示すブロック図
【図２】同実施の形態２における適応アンテナ装置の構成を示すブロック図
【図３】同実施の形態３における適応アンテナ装置の構成を示すブロック図
【図４】同実施の形態４における適応アンテナ装置の構成を示すブロック図
【図５】同実施の形態５における適応アンテナ装置の構成を示すブロック図
【図６】同実施の形態５における適応アンテナ装置の構成を示すブロック図
【図７】同実施の形態６における適応アンテナ装置の構成を示すブロック図
【図８】同実施の形態６における到来方向推定処理部の動作を示すフローチャート
【図９】従来の適応アンテナ装置の構成を示すブロック図
【符号の説明】
１アレーアンテナ
１―１〜１―Ｍアンテナ素子
２―１〜２―Ｍ高周波信号
３―１〜３―Ｍ受信部
４―１〜４―Ｍ受信信号
５主波方向推定部
６角度広がり推定部
７ウエイト生成部
８受信ビーム形成部
９復調部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an adaptive antenna device that varies antenna directivity based on a direction and angular spread estimation result using an array antenna.
[0002]
[Prior art]
There are MUSIC, ESPRIT, Capon, and Fourier methods as methods for estimating the arrival direction of radio waves using an array antenna composed of a plurality of antenna elements. For example, regarding the MUSIC method, the document R.I. O. Schmidt, “Multiple Emitter Location and Signal Parameter Estimate”, IEEE Trans. , AP-34, pp. 276-280 (1986).
[0003]
Further, as an estimation method of the angular spread of an incoming wave, N.I. S. M.M. Shah et al., “Simultaneous Estimation of Direction of Arrival and Angle Spread Using MUSIC Algorithm”, 2000 IEICE Communication Society B-1-31. Further, when the desired wave and interference wave directions are known, the DCMP method is generally known as a beam forming algorithm for directing a directional beam in the desired wave direction and directing a null in the interference wave direction.
[0004]
Furthermore, Japanese Patent Laid-Open No. 2000-216620 is disclosed as a method for adaptively changing the antenna directivity based on the estimation result of the arrival direction of radio waves. The operation will be described below with reference to FIG. First, a plurality of receiving antennas 50-1 to 50-L, a signal distributing means 52 that distributes the high-frequency signals 51-1 to 51-L received by these receiving antennas, respectively, and the signal distributing means 52 Using one of the distributed high-frequency signals, a covariance matrix of the received signals received by the plurality of antennas 50-1 to 50-L is obtained, and the directions of a plurality of incoming waves are measured based on the covariance matrix. An azimuth measuring unit 53 using the MUSIC method for outputting a dispersion matrix and azimuth information of a plurality of incoming waves, and one specified by the azimuth information of a plurality of arriving waves obtained as a result of measurement by the azimuth measuring unit 53 The designation signal storage means 54 for storing the azimuth information and the high frequency signal of the other system distributed by the signal distribution means 52 are received and stored by the specification signal storage means 54. A weighting calculation circuit 55 that calculates a weight for suppressing a signal other than one designated direction based on the covariance matrix, and the plurality of receiving antennas 50-1 to 50-1 by the weighting calculated by the weighting calculation circuit 55. A weighting means 56 for weighting the high-frequency signals 51-1 to 51-L received at 50-L and a signal synthesizing means 57 for synthesizing and outputting the high-frequency signals output from the weighting means. The demodulator 58 demodulates the output of the means 57.
[0005]
[Problems to be solved by the invention]
Conventionally, a directional beam is formed with respect to the estimated direction of arrival of the desired wave. However, in an actual propagation environment, radio waves arrive with an angular spread due to the influence of reflection and diffraction by buildings around the radio station. To do. When directing a directional beam in the direction of the arrival wave of a desired wave, the formation of an optimal directional beam according to the angular spread has not been considered conventionally. Further, in an environment where a plurality of waves arrive, as a method for selecting an optimal incoming wave, the maximum power wave is generally selected. However, even if the received power is large, there is a possibility of selecting a radio wave containing a lot of multipath waves.
[0006]
The present invention makes the beam width in directional beam forming variable using the angular spread estimation result. It is another object of the present invention to provide an adaptive antenna apparatus that improves the transmission / reception quality by selecting an arrival wave direction having a small angular spread when a plurality of arrival waves are present and directing a directional beam in this direction. Furthermore, with respect to the interference wave direction, by forming a null with a null width corresponding to the angular spread of the interference wave, an adaptive antenna that enables robust interference wave suppression even when arrival direction estimation errors are included An object is to provide an apparatus.
[0007]
[Means for Solving the Problems]
According to the present invention, the main wave direction estimating unit that estimates the arrival direction of the arriving wave having the maximum power using the output signal of the receiving unit, and the angle that estimates the angular spread in the arrival direction of the arriving wave having the maximum power A spread estimator and a weight generator that directs the directivity of the array antenna in the direction of arrival of the arriving wave having the maximum power, and further generates an array weight whose beam width is variable based on the estimation result of the angular spread estimator By this, the directivity of the array antenna having the optimum beam width can be formed by the angular spread in the desired wave direction.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 of the present invention is an array antenna composed of a plurality of antenna elements, and a receiving unit that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna; A main wave direction estimation unit that estimates an arrival direction of an incoming wave having the maximum power using an output signal of the reception unit, and an arrival direction of the arrival wave having the maximum power using an output of the main wave direction estimation unit An angle spread estimation unit for estimating the angle spread, and directing the array antenna in the direction of arrival of the arriving wave having the maximum power, and the beam width thereof is varied based on the estimation result of the angle spread estimation unit. A weight generation unit that generates weights, a reception beam forming unit that multiplies the output signals of the reception unit by the array weights and combines them, and an output signal of the reception beam formation unit And a demodulating unit that performs demodulation processing, the beam width of the main lobe can be varied according to the angular spread with respect to the main wave direction, and if the angular spread is larger than a predetermined value, It has the effect of further enhancing the multipath suppression effect by directing the directivity of the narrow beam from the main wave direction including the path.
[0009]
  The invention according to claim 2 of the present invention is an array antenna composed of a plurality of antenna elements, and a receiving unit that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna; An arrival direction estimation unit that estimates an arrival direction and power of a plurality of arrival waves using the output signal of the reception unit, and a maximum power wave is selected from the plurality of arrival waves using an output of the arrival direction estimation unit And an angle spread estimation unit for estimating an angle spread for an incoming wave having a power within a predetermined value with respect to the maximum power wave among the plurality of incoming waves, and a power within a predetermined value with respect to the maximum power wave A weight generation unit for generating an array weight for directing the directivity of the array antenna in a direction in which the angular spread is minimum when there is an incoming wave, and in the maximum power wave direction when there is no incoming wave, A receive beam forming unit for multiplying said array weight to the output signal of the serial receiver synthesis, adaptive antenna device der having a demodulator that performs demodulation processing on the output signal of the receiving beam forming unitThus, the beam width of the directivity formed by the weight generation unit is an adaptive antenna device that varies based on the estimation result of the angular spread estimation unit.Therefore, it is possible to direct the main beam in the direction of arrival of the incoming wave with the smallest angular spread, relatively good received power, and small delay dispersion between the elementary waves constituting the angular spread. Receiving can be performed selectively, and the reception quality can be improved by enhancing the multipath suppression effect.
Furthermore, it is possible to transmit with a directivity pattern in which the beam width of the main lobe is changed according to the angular spread of the incoming wave, and interference can be sufficiently reduced for radio stations existing other than the radio station that is to communicate. Has an effect.
[0010]
  The invention according to claim 3 of the present invention is an array antenna composed of a plurality of antenna elements, and a receiving unit that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna; A main wave direction estimation unit that estimates an arrival direction of an incoming wave having the maximum power using an output signal of the reception unit, and an arrival direction of the arrival wave having the maximum power using an output of the main wave direction estimation unit An angle spread estimation unit for estimating the angle spread, and directing the directivity of the array antenna toward the arrival direction of the incoming wave having the maximum powerFurther, the beam width can be varied based on the estimation result of the angular spread estimation unit.An adaptive antenna apparatus comprising: a weight generating unit that generates an array weight; a transmission beam forming unit that multiplies a transmission signal by the array weight; and a transmission unit that transmits an output of the transmission beam forming unit from the array antenna. Yes, it can be transmitted with a directivity pattern in which the beam width of the main lobe is variable according to the angular spread of the incoming wave, and interference can be sufficiently reduced for radio stations that exist other than the radio station that is to communicate. Has an effect.
[0011]
  The invention according to claim 4 of the present invention is an array antenna composed of a plurality of antenna elements, and a receiving unit that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna; An arrival direction estimation unit that estimates an arrival direction and power of a plurality of arrival waves using the output signal of the reception unit, and a maximum power wave is selected from the plurality of arrival waves using an output of the arrival direction estimation unit And an angle spread estimation unit for estimating an angle spread for an incoming wave having a power within a predetermined value with respect to the maximum power wave among the plurality of incoming waves, and a power within a predetermined value with respect to the maximum power wave A weight generating unit for generating array weights for directing the directivity of the array antenna in a direction in which the angular spread is minimum when the incoming wave is present, and in the direction of the maximum power wave when the incoming wave is not present; Adaptive antenna device comprising a transmitting beamformer for multiplying said array weight with respect to the signal, and a transmission unit for transmitting an output of the transmit beam forming unit from said array antennaAn adaptive antenna device in which the directivity beam width formed by the weight generation unit is variable based on the estimation result of the angular spread estimation unitInterference can be sufficiently reduced for radio stations other than the desired radio station to communicate with, and when there are a plurality of incoming waves, the received power is relatively good, and , It is possible to select an arrival direction with a small delay dispersion between the elementary waves constituting the angular spread, and to transmit in that direction, thereby improving reception quality at a desired radio station. .
Furthermore, it is possible to transmit with a directivity pattern in which the beam width of the main lobe is changed according to the angular spread of the incoming wave, and interference can be sufficiently reduced for radio stations existing other than the radio station that is to communicate. Has an effect.
[0013]
  Claims of the invention5In the invention according to claim 1, the weight generating unit forms a directional beam with a narrowed beam width when the angular spread is larger than a predetermined value.Or any of 4The adaptive antenna apparatus described above has an effect of transmitting and receiving with a directivity pattern in which the beam width of the main lobe is changed according to the angular spread of the incoming wave.
[0014]
  Claims of the invention6The invention described in 1) includes an array antenna including a plurality of antenna elements, a receiving unit that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna, and an output signal of the receiving unit A main wave direction estimating unit that estimates the direction of arrival of an incoming wave having the maximum power using the interference wave arrival direction estimating unit that estimates the direction of arrival of the interference wave using the output signal of the receiving unit, and the interference wave An interference wave angular spread estimation unit that estimates the angular spread of the arrival direction of the interference wave using the output of the arrival direction estimation unit, and directs the directivity of the array antenna toward the arrival direction of the arrival wave having the maximum power, When the direction of the arrival wave having the maximum power and the arrival direction of the interference wave are not the same, an array weight that forms a directivity null having a width corresponding to the interference wave angular spread is formed in the arrival direction of the interference wave. An adaptive antenna apparatus comprising: a weight generating unit to be configured; a reception beam forming unit that multiplies the output signal of the reception unit by the array weight; and a demodulation unit that performs a demodulation process on the output signal of the reception beam forming unit The null width corresponding to the angular spread of the interference wave can be formed, and even when the direction of arrival estimation includes an error, the directivity with a high interference wave suppression effect is formed, thereby improving the reception quality. Has the effect of improving.
[0015]
  Claims of the invention7The invention described in 1) includes an array antenna including a plurality of antenna elements, a receiving unit that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna, and an output signal of the receiving unit A direction of arrival estimation unit that estimates the arrival directions and powers of a plurality of arrival waves using, and selects a maximum power wave from the plurality of arrival waves using an output of the direction of arrival estimation unit, and the plurality of arrivals Among the waves, an angular spread estimation unit that estimates an angular spread for an incoming wave whose power is within a predetermined value with respect to the maximum power wave, and an interference that estimates an arrival direction of an interference wave using an output signal of the reception unit A wave arrival direction estimation unit, an interference wave angle spread estimation unit that estimates an angular spread in the arrival direction of the interference wave using an output of the interference wave arrival direction estimation unit, and an arrival wave power for the maximum power wave is predetermined. Less than The direction of the array antenna is directed to the direction in which the angular spread is minimum when the incoming wave is present, and the direction of the array antenna is directed to the direction of the maximum power wave when the incoming wave is not present, and the direction of the array antenna When the arrival directions of the interference waves are not the same, a weight generation unit that generates an array weight that forms a directivity null with a width corresponding to the interference wave angular spread in the arrival direction of the interference waves, and an output signal of the reception unit And a receiving beam forming unit that multiplies and combines the array weights and a demodulating unit that performs demodulation processing on the output signal of the receiving beam forming unit, and a null width corresponding to the angular spread of the interference wave Even when the direction of arrival estimation includes an error, the directivity with high interference wave suppression effect is formed, so that the reception quality can be improved.
[0016]
  Claims of the invention8The invention described in 1) includes an array antenna including a plurality of antenna elements, a receiving unit that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna, and an output signal of the receiving unit A main wave direction estimator for estimating the direction of arrival of the incoming wave having the maximum power using the interference wave arrival direction estimator for estimating the direction of arrival of the interference wave using the output signal of the receiver, and the arrival of the interference wave An interference wave angular spread estimation unit that estimates an angular spread of the interference wave arrival direction using an output of the direction estimation unit; and directs the array antenna toward the arrival direction of the arrival wave having the maximum power, and the maximum power If the direction of the arrival wave having the same direction as the arrival direction of the interference wave is not the same, an array weight is formed in the arrival direction of the interference wave to form a directivity null with a width corresponding to the angular spread of the interference wave. A weight generating unit that, with respect to the transmission signal
An adaptive antenna apparatus having a transmission beam forming unit that multiplies the array weight and a transmission unit that transmits the output of the transmission beam forming unit from the array antenna, and forms a null width according to the angular spread of the interference wave Even when the direction of arrival estimation includes an error, the directivity with high interference wave suppression effect is formed, and thus the communication quality at the time of transmission can be improved.
[0017]
  Claims of the invention9The invention described in 1) includes an array antenna including a plurality of antenna elements, a receiving unit that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna, and an output signal of the receiving unit A direction of arrival estimation unit that estimates the arrival directions and powers of a plurality of arrival waves using, and selects a maximum power wave from the plurality of arrival waves using an output of the direction of arrival estimation unit, and the plurality of arrivals Among the waves, an angular spread estimation unit that estimates an angular spread for an incoming wave whose power is within a predetermined value with respect to the maximum power wave, and an interference that estimates an arrival direction of an interference wave using an output signal of the reception unit A wave arrival direction estimation unit, an interference wave angle spread estimation unit that estimates an angular spread in the arrival direction of the interference wave using an output of the interference wave arrival direction estimation unit, and an arrival wave power for the maximum power wave is predetermined. Less than The direction of the array antenna is directed to the direction in which the angular spread is minimum when the incoming wave is present, and the direction of the array antenna is directed to the direction of the maximum power wave when the incoming wave is not present, and the direction of the array antenna If the arrival directions of the interference waves are not the same, a weight generation unit that generates an array weight that forms a directivity null with a width corresponding to the interference wave angular spread in the arrival direction of the interference waves, and the array for the transmission signal An adaptive antenna apparatus having a transmission beam forming unit for multiplying weights and a transmission unit for transmitting the output of the transmission beam forming unit from the array antenna, and forming a null width according to the angular spread of an interference wave Even if there is an error in the direction of arrival estimation, it has the effect of improving the communication quality at the time of transmission by forming the directivity with high interference wave suppression effect
[0018]
  Claims of the invention10The invention according to claim 1, wherein the arrival direction estimation algorithm in the main wave direction estimation unit is switched according to the angular spread of the arrival wave.1 or 3The adaptive antenna device described above has an effect of being able to select an optimum direction of arrival estimation according to the angular spread and improving the estimation accuracy.
[0019]
  Claims of the invention11The invention according to claim 2, wherein the arrival direction estimation algorithm in the arrival direction estimation unit is switched according to the angular spread of the incoming wave.7 or 9The adaptive antenna device described above has an effect of being able to select an optimum direction of arrival estimation according to the angular spread and improving the estimation accuracy.
[0020]
  Claims of the invention12The invention according to claim 1 switches the arrival direction estimation algorithm in the interference wave arrival direction estimation unit according to the angular spread of the interference wave.6 to 9The adaptive antenna device according to any one of the above has an effect of being able to select an optimal direction of arrival estimation according to the angular spread and improving the estimation accuracy.
[0021]
  Claims of the invention13The invention according to claim 1, wherein when the angular spread is larger than a predetermined value, the direction-of-arrival estimation algorithm is switched to an algorithm to which a spatial smoothing process is added.10, 11 or 12The adaptive antenna device described above has an effect of being able to select an optimum direction of arrival estimation according to the angular spread and improving the estimation accuracy.
[0022]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0023]
(Embodiment 1)
FIG. 1 is a block diagram showing the configuration of the adaptive antenna apparatus. The operation will be described below with reference to FIG. The array antenna 1 is composed of M (where M> 1) antenna elements 1-1 to 1-M. The high-frequency signals 2-1 to 2-M received by the antenna elements 1-1 to 1-M are frequency-converted by the receiving units 3-1 to 3-M connected to the antenna elements 1-1 to 1-M. Are orthogonally demodulated and converted to received signals 4-1 to 4-M consisting of orthogonal I and Q signals. Each of the received signals 4-1 to 4-M is divided into two, one being input to the main wave direction estimating unit 5 and the other being input to the receiving beam forming unit 8.
[0024]
The main wave direction estimation unit 5 estimates the arrival direction of the incoming wave having the maximum power. Hereinafter, the operation will be described. Hereinafter, a sampled signal is used for each of the I signal and the Q signal, and a complex digital signal expressed as a real part and a Q signal as an imaginary part is represented as a received signal x (k). First, the received signal x at the sampling time kΔT (where k is a natural number and ΔT is the sampling interval) respectively obtained from the received signals 4-1 to 4-M.₁(K), x₂(K),. . . , X_MA reception vector x (k) expressed by (k) to (Equation 1) is configured, and further, a correlation matrix R of (Equation 2) is obtained using the reception vector x (k) accumulated every predetermined N sample periods. . In this case, the correlation matrix R is an (M × M) matrix.
[0025]
[Expression 1]

[0026]
[Expression 2]

[0027]
Next, the arrival angle is evaluated for each predetermined angle step Δθ using the arrival angle evaluation function by the Capon method. The angle-of-arrival evaluation function is described in J. Capon, “High-Resolution Frequency-Wavenumber Spectrum Analysis.” Proc. IEEE, 57 (8), pp. 1408-1418, 1969, and is represented by (Equation 3).
[0028]
[Equation 3]

[0029]
However, a (θ) represents the complex response of the array antenna with respect to the azimuth θ. (Hereinafter referred to as an array mode vector) and R^-1Is the inverse of R.
[0030]
In the angle spectrum of the result of the arrival angle evaluation, several local maximum values are obtained. The maximum peak among them is the maximum power wave, and the angle giving the maximum peak is the main wave direction θ.₀And
[0031]
Next, the operation in the angular spread estimation unit 6 will be described below.
[0032]
Main wave direction θ obtained from main wave direction estimation unit 5₀The angular spread parameter δ is evaluated for each predetermined angular step Δδ using an angular spread evaluation function expressed by (Equation 4).
[0033]
[Expression 4]

[0034]
However, a_x(Θ) is a generalized array mode vector extended from the array mode vector a (θ) to take an argument in the complex region. The angular spread value δ giving the maximum peak for the angular spread spectrum obtained by varying the angular spread parameter δ in (Equation 4).₀Is an estimated value.
[0035]
Note that here, the angular spread is estimated using the generalized array mode vector in contrast to the Capon method, but the angular spread estimation is performed by applying the generalized array mode vector as in the MUSIC method and ESPRIT method. Is the same.
[0036]
The weight generation unit 7 calculates the main wave direction estimated value θ₀And its angular spread estimate δ₀To change the main beam direction to θ₀The beam width is δ₀Generate array weights with directivity according to. In the following, the operation when the Dorf-Chebyshev directivity synthesis method is used will be described. In the Dorf-Chebyshev directivity synthesis method, the side lobe suppression value SLL for the main lobe can be arbitrarily set by determining the excitation distribution so that the antenna directivity matches the Chebyshev polynomial, and the sidelobe suppression value SLL. The beam width of the main lobe is narrowed by reducing. For details, see, for example, W.W. L. Stuzman et al., “Antenna Theory and Design”, Wiley, 1981, pp. 537-542. Here, the outline is shown below for the case of using an 8-element linear array antenna. In the case of 8 elements (M = 8), the main lobe direction is θ₀Thus, the array weight which is the sidelobe suppression value SLL is expressed by (Equation 5).
[0037]
[Equation 5]

[0038]
Where s_mIs given by (Equation 6) to (Equation 10) below.
[0039]
[Formula 6]

[0040]
[Expression 7]

[0041]
[Equation 8]

[0042]
[Equation 9]

[0043]
[Expression 10]

[0044]
Where m = 1 to 8, λ is the carrier wavelength, and d is the array element spacing.
[0045]
Here, when the angular spread is larger than the predetermined value A1, the weight generating unit 7 forms a directional beam with a narrowed beam width. For example, set A1 = 10 °, and δ₀If ≦ 10 °, SLL = 20 dB and δ₀If> 10 °, by setting SLL = 10 dB, the weight generating unit 7 can form a directional beam with a narrowed beam width when the angular spread is larger than the predetermined value A1.
[0046]
The reception beam forming unit 8 uses the array weight obtained by the weight generation unit 7 to multiply and synthesize the reception signal. That is, as shown in (Equation 11), the received signal x_mA composite signal y (k) is output for (k). However, * shows a complex conjugate.
[0047]
## EQU11 ##

[0048]
The demodulator 9 demodulates the combined signal y (k) from the reception beam forming unit 8 and outputs decoded data.
[0049]
As described above, in the present embodiment, the weight generator 7 can vary the beam width of the main lobe according to the angular spread with respect to the main wave direction. When the angular spread is large, the temporal dispersion between the elementary waves that make up the angular spread also becomes large. Therefore, when the angular spread is larger than a predetermined value, the narrow beam is directed from the main wave direction including those multipaths. Therefore, the multipath suppression effect can be further enhanced and reception quality can be improved.
[0050]
(Embodiment 2)
FIG. 2 is a block diagram showing the configuration of the adaptive antenna apparatus. The operation will be described below with reference to FIG. The array antenna is composed of M (where M> 1) antenna elements 1-1 to 1-M. The high-frequency signals 2-1 to 2-M received by the antenna elements 1-1 to 1-M are frequency-converted by the receiving units 3-1 to 3-M connected to the antenna elements 1-1 to 1-M. Are orthogonally demodulated and converted to received signals 4-1 to 4-M consisting of orthogonal I and Q signals. Each reception signal 4-1 to 4-M is divided into two, one being input to the arrival direction estimation unit 10 and the other being input to the reception beam forming unit 8.
[0051]
The arrival direction estimation unit 10 estimates the arrival directions of a plurality of arrival waves and their powers using the output signal of the reception unit. The operation will be described below. Hereinafter, a sampled signal is used for each of the I signal and the Q signal, and a complex digital signal expressed as a real part and a Q signal as an imaginary part is represented as a received signal x (k). First, the received signal x at the sampling time kΔT (where k is a natural number and ΔT is the sampling interval) respectively obtained from the received signals 4-1 to M.₁(K), x₂(K),. . . , X_MA reception vector x (k) expressed by (k) to (Equation 1) is configured, and further, a correlation matrix R of (Equation 2) is obtained using the reception vector x (k) accumulated every predetermined N sample periods. . In this case, the correlation matrix R is an (M × M) matrix. Next, the arrival angle is evaluated for each predetermined angle step Δθ using the arrival angle evaluation function based on the MUSIC method. The arrival angle evaluation function is expressed by (Equation 12).
[0052]
[Expression 12]

[0053]
Where E_NIs a noise space matrix and is obtained as follows. When the number of incoming waves is S, the eigenvalue λ obtained by eigenvalue decomposition of the correlation matrix R₁~ Λ_MAre arranged in descending order and have the relationship of (Equation 13), and the eigenvectors e of (MS) correlation matrices R belonging to the noise eigenvector space_sE with column vector_N= [E_{s + 1},. . . , E_MForm a noise eigenspace matrix.
[0054]
[Formula 13]

[0055]
Since the arrival wave number S is generally unknown, the distribution of eigenvalues and the document M. Wax and T.W. Kailath, “Detection of Signals by Information Theoretical Criteria”, IEEE Trans. On Acoustics, Speech and Signal Processing, Vol. ASSP33 (2), pp. 387-392, February (1985) is used to determine the number of signals. In addition, as a result of the arrival angle evaluation, several maximum values are obtained in the obtained angle spectrum. The maximum peak among them is the maximum power wave, and the angle giving the maximum peak is the main wave direction θ.₀The remaining (S-1) peak directions are searched in descending order, and each arrival direction is defined as θ_nAnd Here, n = 1,..., S-1. The received power for each direction of arrival is estimated using (Equation 14). Here, n = 0,..., S−1, and I is an M × M unit matrix.
[0056]
[Expression 14]

[0057]
The angle spread estimation unit 11 calculates the maximum power wave and the arrival power with respect to the maximum power wave within the predetermined value Lp from the plurality of arrival directions obtained by the arrival direction estimation unit 10 and its power estimation value. Estimate the angular spread. That is, | P (θ_n) -P (θ₀) | ≦ L_pSatisfy θ_vThe angle spread in the direction of arrival is estimated using only (Equation 15). However, n = 1,..., S-1.
[0058]
[Expression 15]

[0059]
However, a_x(Θ) is a generalized array mode vector extended from the array mode vector to take an argument of the complex region. The angular spread value δ giving the maximum peak with respect to the angular spread spectrum obtained by evaluating the angular spread parameter δ in (Equation 15) for each predetermined angular step Δδ.₀Is estimated angular spread δv with respect to direction of arrival θv₀And
[0060]
Here, although the direction of arrival estimation and the angle spread estimation are performed using the MUSIC method, the estimation can be similarly performed using the ESIPRIT method or the like.
[0061]
When there are a plurality of incoming waves whose angular spread is estimated, the weight generating unit 12 generates an array weight that directs the array antenna main beam in a direction that minimizes the angular spread. When there is one incoming wave whose angular spread is estimated, the main beam is directed in the direction of arrival. As the array weight wk, the Dorf-Chebyshev directivity synthesis method described in the first embodiment can be applied.
[0062]
The reception beam forming unit 8 uses the array weight wk generated by the weight generation unit 12 to multiply and synthesize the reception signal. That is, as shown in (Equation 11), the received signal x_mA composite signal y (k) is output for (k). However, * shows a complex conjugate.
[0063]
The demodulator 9 demodulates the combined signal y (k) from the reception beam forming unit 8 and outputs decoded data.
[0064]
As described above, in the present embodiment, in the arrival direction estimation unit 10 and the angular spread estimation unit 11, when there are a plurality of arrival waves whose arrival power is within a predetermined value with respect to the maximum power wave, The main beam can be directed in the direction of arrival of the incoming wave with the smallest angular spread, the received power is relatively good, and the incoming wave with a small delay dispersion between the elementary waves forming the angular spread is selected. Reception quality can be improved, and the reception quality can be improved by increasing the multipath suppression effect.
[0065]
In the present embodiment, the width of the main beam with respect to the angular spread was not particularly described. However, as described in the first embodiment, the beam width can be varied according to the estimated angular spread. Good. In this case, in addition to the effects described above, the effects described in the first embodiment are added.
[0066]
(Embodiment 3)
FIG. 3 is a block diagram showing the configuration of the adaptive antenna apparatus. The operation will be described below with reference to FIG. The array antenna is composed of M (where M> 1) antenna elements 1-1 to 1-M. The high-frequency signals 2-1 to 2-M received by the antenna elements 1-1 to 1-M are frequency-converted by the receiving units 3-1 to 3-M connected to the antenna elements 1-1 to 1-M. After being demodulated, the signals are orthogonally demodulated, converted into reception signals 4-1 to 4-M consisting of orthogonal I and Q signals, and input to the main wave direction estimation unit 5.
[0067]
A main wave direction estimation unit 5 that estimates the arrival direction of an incoming wave having the maximum power using the output signal 4 of the reception unit 3 and an angular spread estimation unit 6 that estimates an angular spread in the arrival direction of the arrival wave having the maximum power. The operation of the weight generation unit 7 that directs the directivity of the array antenna in the direction of arrival of the arriving wave having the maximum power and generates an array weight whose beam width is variable based on the estimation result of the angular spread estimation unit 6 is as follows. This is the same as in the first embodiment, and a description thereof is omitted.
[0068]
The modulation unit 20 modulates input transmission data to generate a baseband I signal I (k) and a Q signal Q (k). The transmission beam forming unit 21 distributes the modulated baseband I signal I (k) and Q signal Q (k) in a number equal to the number M of array elements to transmit, and multiplies each by the array weight wm. (M = 1,..., M) That is, the input signal zm (k) = wm × (I (k) + jQ (k)) to the m-th transmitter. However, m = 1 to M.
[0069]
The transmission units 22-1 to 22-M convert the input baseband signal zm (k) into an RF transmission frequency, and transmit it from each array element of the array antenna with a specified transmission power.
[0070]
As described above, in the present embodiment, the arrival direction of the radio wave is estimated from the signal received by the array antenna 1, the main lobe is directed to the arrival wave direction, and the beam of the main lobe according to the angular spread of the arrival wave It is possible to transmit with a directivity pattern having a variable width. As a result, interference can be sufficiently reduced with respect to radio stations existing other than the radio station with which communication is to be performed, and when the angular spread is large, the temporal dispersion between the elementary waves constituting the angular spread also increases. Therefore, when the angular spread is larger than the predetermined value, the multipath suppression effect can be further enhanced by directing the directivity of the narrow beam from the main wave direction including those multipaths. Reception quality can be improved.
[0071]
(Embodiment 4)
FIG. 4 is a block diagram showing the configuration of the adaptive antenna apparatus. The operation will be described below with reference to FIG. The array antenna is composed of M (where M> 1) antenna elements 1-1 to 1-M. The high-frequency signals 2-1 to 2-M received by the antenna elements 1-1 to 1-M are frequency-converted by the receiving units 3-1 to 3-M connected to the antenna elements 1-1 to 1-M. Is then orthogonally demodulated, converted into received signals 4-1 to 4-M consisting of orthogonal I and Q signals, and input to the arrival direction estimation unit 10.
[0072]
The arrival direction estimation unit 10 that estimates the arrival directions of the plurality of incoming waves and their powers using the output signals 4-1 to 4-M of the reception units 3-1 to 3-M, and the maximum of the plurality of arrival directions. There is an electric wave, an angle spread estimation unit 11 that estimates an angular spread of an incoming wave power within a predetermined value with respect to the maximum power wave, and an incoming wave with an incoming wave power within a predetermined value with respect to the maximum power wave. In this case, the weight generation unit 12 for generating the array weight for directing the directivity of the array antenna in the direction in which the angular spread is minimized, or in the direction of the maximum power wave in the absence of the angle spread, is the same as that of the second embodiment. Description is omitted.
[0073]
The transmission beam forming unit 21 distributes the transmission data in the modulation unit 20 in a number equal to the number of array elements that transmit the modulated baseband I signal I (k) and Q signal Q (k). Multiply the weight wk. That is, the input signal zm (k) = wm × (I (k) + jQ (k)) to the m-th transmitter 22 is obtained. However, m = 1 to M.
[0074]
The transmission units 22-1 to 22-M convert the input baseband signal zm (k) into an RF transmission frequency, and transmit it from each array element of the array antenna with a specified transmission power.
[0075]
As described above, in the present embodiment, the arrival direction of the radio wave is estimated from the signal received by the array antenna, the main lobe is directed to the arrival wave direction, and the beam width of the main lobe is set according to the angular spread of the arrival wave. Transmission with a variable directivity pattern is possible. As a result, interference can be sufficiently reduced with respect to radio stations existing other than the desired radio station to communicate, and when there are a plurality of incoming waves, the received power is relatively good, and It is possible to select an arrival direction having a small delay dispersion between the elementary waves constituting the angular spread, and to transmit in the direction, thereby improving reception quality in a desired radio station.
[0076]
(Embodiment 5)
FIG. 5 is a block diagram showing the configuration of the adaptive antenna apparatus. The operation will be described below with reference to FIG. In FIG. 5, the configuration of the adaptive antenna apparatus according to the first embodiment is omitted, and the angle spread estimation unit 6 is eliminated, and the interference wave arrival direction estimation unit 31 and the interference wave angle spread estimation unit 32 are added. It is configured to generate an array weight that suppresses interference waves. The different parts will be mainly described below.
[0077]
The operations until the received signal 4 is obtained by the array antenna 1 and the receiving unit 3 are the same as those in the first embodiment. The main wave direction estimation unit 5 estimates the arrival direction of the arriving wave having the maximum power by using the output signal 4 from the reception unit 3 by the operation in the first embodiment.
[0078]
The interference wave arrival direction estimation unit 31 estimates the arrival direction of the interference wave using the output signal 4 of the reception unit 3. Here, in the case of TDMA and FDMA, the interference wave is an arrival wave having a delay time that cannot be equalized by an equalizer in the subsequent demodulator 9, or an interference wave from another cell. Assumes users assigned to different codes. In the case of the DS-CDMA system in IMT-2000, communication in an environment where users who perform high-speed data communication and low-speed data communication or voice users are mixed is assumed, and transmission power is also particularly high for users who perform high-speed data communication. Therefore, the degree of interference with other users increases.
[0079]
Hereinafter, an operation when the present embodiment is applied as a CDMA base station will be described. The interference wave arrival direction estimation unit 31 uses the received signal 4 to perform despreading using codes assigned to other users. A signal sampled for each of the despread I signal and Q signal of the received signal is used, and a complex digital signal expressed as a real part of the I signal and an imaginary part of the Q signal is represented as a received signal h (t). . Received signal h at sample time kΔT (where k is a natural number and ΔT is a sampling interval) obtained from each despread received signal₁(K), h₂(K),. . . , H_MA reception vector h (k) expressed by (k) to (Equation 16) is configured, and further, a correlation matrix R of (Equation 17) is used by using the reception vector h (k) accumulated every predetermined N sample periods._hAsk for. In this case, the correlation matrix R_hBecomes an (M × M) matrix.
[0080]
[Expression 16]

[0081]
[Expression 17]

[0082]
Next, using the arrival angle evaluation function by the Capon method, the arrival angle is evaluated for each predetermined angle step Δφ. The arrival angle evaluation function is expressed by (Equation 18).
[0083]
[Formula 18]

[0084]
In the angle spectrum of the result of the arrival angle evaluation, several local maximum values are obtained, and the maximum peak among them is the maximum power wave, and the angle giving the maximum peak is the interference wave direction φ₀And
[0085]
Next, the operation in the interference wave angle spread estimation unit 32 will be described below. Main wave direction φ obtained from the interference wave arrival direction estimation unit 31₀The angular spread parameter ψ is evaluated for each predetermined angular step Δψ using the angular spread evaluation function represented by (Equation 19).
[0086]
[Equation 19]

[0087]
The angular spread value ψ giving the maximum peak with respect to the angular spread spectrum obtained by varying the angular spread parameter ψ in (Equation 19)₀Is an estimated value. Note that here, the angular spread is estimated using the generalized array mode vector for the Capon method, but the angular spread estimation is performed by applying the generalized array mode vector to the MUSIC method and ESPRIT method in the same manner. Is the same.
[0088]
The weight generation unit 30 directs the directivity of the array antenna in the direction of arrival, and when the direction of arrival and the interference wave direction are not the same, an array weight that forms a directivity null with a width corresponding to the interference wave angular spread in the interference wave direction Is generated. As a method for forming an array weight when the desired wave direction and the interference wave direction are known, the DCMP method is representative. Details of the DCMP method can be found in K.K. Takano, “An Adaptive Array Under Directional Constraint”, IEEE Trans. AP-24 (5), 1976. The constraint matrix C is represented by the arrival direction θ as shown in (Equation 20).₀Array mode vector a (θ₀), Interference wave direction φ₀Array mode vector a (φ₀Further, in order to make the null width in accordance with the angular spread in the interference wave direction, the array mode vector a (φ in the vicinity of the interference wave direction in accordance with the angular spread₀―Αψ₀), A (φ₀+ Αψ₀). Where α is a constant. Further, the constraint response vector H is represented by (Equation 21). However, T represents matrix transposition. The optimum weight Wopt obtained by the DCMP method is represented by (Equation 22). By using Wopt as an array weight, directivity of the array antenna is directed to the arrival direction, and if the arrival direction and the interference wave direction are not the same, a directivity null with a width corresponding to the interference wave angular spread is formed in the interference wave direction. An array weight can be generated. Note that the number of constraint conditions can be reduced from 4 to 3 by using (Equation 23) and (Equation 24) instead of (Equation 20) and (Equation 21) as the constraint matrix C and the constraint response vector H. If the number of array elements is small, the calculation amount can be reduced and the present invention can be applied to the case where the number of array elements is small.
[0089]
[Expression 20]

[0090]
[Expression 21]

[0091]
[Expression 22]

[0092]
[Expression 23]

[0093]
[Expression 24]

[0094]
By using the array weight obtained as described above for forming the reception beam or the transmission beam, a null width corresponding to the angular spread of the interference wave can be formed, and the arrival direction estimation includes an error. Even in this case, it is possible to improve the communication quality at the time of reception or transmission by forming directivity with a high interference wave suppression effect.
[0095]
In addition, instead of the main wave direction estimation unit 5 in the present embodiment, the arrival wave power is increased with respect to the maximum power wave by using the arrival direction estimation unit 10 and the angular spread estimation unit 11 described in the second embodiment. When there are a plurality of arriving waves within a predetermined value, the main beam may be directed to the arrival direction of the arriving wave having the smallest angular spread among the arriving waves.
[0096]
In the third embodiment, the interference wave arrival direction estimation unit 31 and the interference wave angle spread estimation unit 32 of the present embodiment may be used, and the configuration in that case is as shown in FIG. The operations of the arrival direction estimation unit 31 and the interference wave angle spread estimation unit 32 are the same as those of the present embodiment, and other operations are the same as those of the third embodiment, and the same effects as those of the present embodiment are obtained. . In this case, the arrival direction estimation unit 10 and the angular spread estimation unit 11 described in the fourth embodiment may be used instead of the main wave direction estimation unit 5.
[0097]
(Embodiment 6)
FIG. 7 is a block diagram showing another configuration of the adaptive antenna apparatus. Hereinafter, in FIG. 7, the estimation result of the angle spread estimation unit 41 is fed back to the main wave direction estimation unit 40, and a function of performing an operation of switching the direction estimation algorithm in the main wave direction estimation unit 40 using this information is added. ing. Below, operation | movement of the main wave direction estimation part 40 which is mainly different parts is demonstrated using the flowchart of FIG.
[0098]
The operations until the received signal 4 is obtained by the array antenna 1 and the receiving unit 3 are the same as those in the first embodiment (s70). First, the main wave direction estimation unit 40 estimates the arrival direction of the received signal 4 by the first arrival direction estimation process (s71). Here, the first direction-of-arrival estimation processing is performed after the correlation matrix calculation (s71-1) shown in (Expression 2), and then the arrival direction estimation evaluation function calculation (s71-2) shown in (Expression 3) or (Expression 12). )I do. The obtained arrival direction estimation result is input to the angular spread estimation unit 41 to obtain an estimated angular spread value (s72). The obtained angle spread value φ is compared with a predetermined value AS (s73). If φ ≦ AS, the arrival direction estimated value at that time is set as a final estimated value (s74). On the other hand, if φ> AS, second arrival direction estimation processing is performed (s75). Here, in the second direction-of-arrival estimation process, after the correlation matrix calculation (s75-1) shown in (Expression 2), the obtained correlation matrix is further subjected to a spatial smoothing process with the number of subarray elements Ms (s75). -2) Using the correlation matrix Rs obtained thereby, the arrival direction estimation evaluation function calculation represented by (Equation 3) or (Equation 12) is performed (s75-3). However, Ms ≦ M. The direction-of-arrival estimated value thus obtained is set as a final estimated value (s74). For details on spatial smoothing, refer to the document Pilali et al, "Forward / Backward Spatial Smoothing Techniques for Coherent Signal Identification", IEEE Trans. On Acoustics, speech and signal processing, VOL.37, NO.1, 1989, etc. Are listed.
[0099]
As described above, in the present embodiment, the arrival direction estimation algorithm in the main wave direction estimation unit 40 can be switched depending on the size of the angular spread. That is, when the angular spread is larger than a predetermined value, the arrival direction estimation algorithm in the main wave direction estimation unit 40 is switched to an algorithm to which a spatial smoothing process is added. If the angular spread exceeds 10 degrees, the elementary waves that form the angular spread can be seen as multipaths with high correlation. Therefore, the rank of the correlation matrix decreases, and the incoming wave cannot be estimated with high accuracy. . Therefore, the estimation accuracy can be improved by performing the arrival direction estimation process with spatial smoothing as shown in the present embodiment. On the other hand, in a region where the angular spread is sufficiently small, it is possible to prevent deterioration in estimation accuracy due to a reduction in the array aperture due to subarraying of the array antenna during the spatial smoothing process.
[0100]
It should be noted that the arrival direction estimation algorithm may be similarly switched according to the angular spread for the main wave direction estimation unit described in the third embodiment of the present invention.
[0101]
It should be noted that the arrival direction estimation algorithm may be similarly switched according to the angular spread for the arrival direction estimation unit described in

Embodiments

2, 4 and 5 of the present invention.
[0102]
Note that the arrival direction estimation algorithm may also be switched according to the angular spread for the interference wave arrival direction estimation unit described in the fifth embodiment of the present invention.
[0103]
【The invention's effect】
As described above, according to the present invention, the directivity of the array antenna at the time of reception or transmission according to the direction of arrival estimation and the angle spread estimation result, the beam direction and the beam width are adaptively set with respect to the position of the radio station. Can be variable. Further, when there is an interfering station, a null can be formed in the direction of the interference wave, and the null width can be varied according to the angular spread. Thus, by applying the present invention to a mobile communication base station that needs to communicate with a plurality of terminal stations, interference between terminals can be reduced, and communication quality and system capacity can be improved. it can.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an adaptive antenna apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a block diagram showing a configuration of an adaptive antenna device according to the second embodiment.
FIG. 3 is a block diagram showing a configuration of an adaptive antenna device according to the third embodiment.
FIG. 4 is a block diagram showing a configuration of an adaptive antenna device according to the fourth embodiment.
FIG. 5 is a block diagram showing a configuration of an adaptive antenna device according to the fifth embodiment.
FIG. 6 is a block diagram showing a configuration of an adaptive antenna device according to the fifth embodiment.
FIG. 7 is a block diagram showing a configuration of an adaptive antenna apparatus according to the sixth embodiment.
FIG. 8 is a flowchart showing the operation of the arrival direction estimation processing unit in the sixth embodiment.
FIG. 9 is a block diagram showing a configuration of a conventional adaptive antenna device
[Explanation of symbols]
1 Array antenna
1-1 to 1-M antenna element
2-1 to 2-M high frequency signal
3-1 to 3-M receiver
4-1 to 4-M Received signal
5 Main wave direction estimation part
6 Angular spread estimation part
7 Weight generator
8 Receive beam forming section
9 Demodulator

Claims

An array antenna composed of a plurality of antenna elements, a receiver that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna, and a maximum power using the output signal of the receiver A main wave direction estimating unit that estimates an arrival direction of an incoming wave, an angle spread estimating unit that estimates an angular spread in the arrival direction of the incoming wave having the maximum power using an output of the main wave direction estimating unit, and A weight generating unit that directs the directivity of the array antenna in the direction of arrival of an arriving wave having maximum power, and further generates an array weight whose beam width is variable based on an estimation result of the angular spread estimating unit; and the receiving unit A receiving beam forming unit that multiplies the output signal by the array weight and synthesizes the output signal, and a demodulating unit that performs demodulation processing on the output signal of the receiving beam forming unit Adaptive antenna apparatus.

An array antenna composed of a plurality of antenna elements; a receiving unit that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna; and a plurality of arrivals using an output signal of the receiving unit A direction-of-arrival estimator for estimating the arrival direction of the waves and their power, and selecting a maximum power wave from the plurality of arriving waves using an output of the direction-of-arrival estimator, and, among the plurality of arriving waves, the maximum An angular spread estimation unit that estimates an angular spread for an incoming wave with a power within a predetermined value with respect to a power wave, and an angular spread when an incoming wave with a power within a predetermined value with respect to the maximum power wave exists. A weight generator for generating an array weight for directing the directivity of the array antenna in the direction of the minimum power, and in the direction of the maximum power wave if not present, and the array of the output signal of the receiver. A adaptive antenna device including a receive beam forming unit for multiplying the Eight synthesis, and a demodulation section that performs demodulation processing on the output signal of the receiving beam forming unit,
The adaptive antenna apparatus in which the directivity beam width formed by the weight generation unit is variable based on an estimation result of the angular spread estimation unit.

An array antenna composed of a plurality of antenna elements, a receiver that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna, and a maximum power using the output signal of the receiver A main wave direction estimating unit that estimates an arrival direction of an incoming wave, an angle spread estimating unit that estimates an angular spread in the arrival direction of the incoming wave having the maximum power using an output of the main wave direction estimating unit, and Directing the directivity of the array antenna in the direction of arrival of the arriving wave having the maximum power, and further generating a weight generator that changes the beam width based on the estimation result of the angular spread estimation unit, and a transmission signal An adaptation comprising: a transmission beam forming unit for multiplying the array weight; and a transmission unit for transmitting the output of the transmission beam forming unit from the array antenna. Antenna equipment.

An array antenna composed of a plurality of antenna elements; a receiving unit that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna; and a plurality of arrivals using an output signal of the receiving unit A direction-of-arrival estimator for estimating the arrival direction of the waves and their power, and selecting a maximum power wave from the plurality of arriving waves using an output of the direction-of-arrival estimator, and, among the plurality of arriving waves, the maximum An angular spread estimation unit that estimates an angular spread for an incoming wave with a power within a predetermined value with respect to a power wave, and an angular spread with a minimum when there is an incoming wave with a power within a predetermined value with respect to the maximum power wave A weight generation unit for generating an array weight for directing the directivity of the array antenna in the direction of the maximum power wave if not present, and the array weight for the transmission signal. A transmit beam forming unit for calculation to, an adaptive antenna device and a transmission unit for transmitting an output of the transmit beam forming unit from said array antenna,
An adaptive antenna apparatus in which a beam width of directivity formed by the weight generation unit is variable based on an estimation result of an angular spread estimation unit.

If the weight generating unit is the angular spread is larger than a predetermined value, the adaptive antenna device according to any one of claims 1 to form a directional beam narrowing the beam width of 4.

An array antenna composed of a plurality of antenna elements, a receiver that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna, and a maximum power using the output signal of the receiver A main wave direction estimating unit that estimates an arrival direction of an incoming wave, an interference wave arrival direction estimating unit that estimates an arrival direction of an interference wave using an output signal of the receiving unit, and an output of the interference wave arrival direction estimating unit An interference wave angular spread estimation unit that estimates the angular spread of the direction of arrival of the interference wave using a directivity of the array antenna in the direction of arrival of the arrival wave having the maximum power, and the arrival wave having the maximum power If the direction of the interference wave and the arrival direction of the interference wave are not the same, a weight that generates an array weight that forms a directivity null with a width corresponding to the interference wave angular spread in the arrival direction of the interference wave A generating unit, a reception beam forming unit, wherein multiplying the array weight to the output signal of the receiver synthesizes, adaptive antenna device to the output signal of the receiving beam forming unit and a demodulation section that performs demodulation processing.

An array antenna composed of a plurality of antenna elements; a receiving unit that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna; and a plurality of arrivals using an output signal of the receiving unit A direction-of-arrival estimator for estimating the arrival direction of the waves and their power, and selecting a maximum power wave from the plurality of arriving waves using the output of the direction-of-arrival estimator, An angular spread estimation unit that estimates an angular spread with respect to an incoming wave of power within a predetermined value with respect to a power wave, and an interference wave arrival direction estimation unit that estimates an arrival direction of an interference wave using an output signal of the receiving unit An interference wave angular spread estimation unit that estimates an angular spread in the arrival direction of the interference wave using an output of the interference wave arrival direction estimation unit, and an arrival wave of power within a predetermined value with respect to the maximum power wave. Exists In some cases, the directivity of the array antenna is directed to the direction in which the angular spread is minimized, and the directivity of the array antenna is directed to the maximum power wave direction in the absence of the angular spread, and the arrival direction of the interference wave is directed to the direction of the array antenna If they are not the same, a weight generation unit that generates an array weight that forms a directivity null with a width corresponding to the interference wave angular spread in the direction of arrival of the interference wave, and the output signal of the reception unit is multiplied by the array weight An adaptive antenna apparatus comprising: a reception beam forming unit that performs synthesis; and a demodulation unit that performs demodulation processing on an output signal of the reception beam forming unit.

An array antenna composed of a plurality of antenna elements, a receiving unit that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna, and a maximum power using the output signal of the receiving unit A main wave direction estimation unit that estimates the arrival direction of the incoming wave, an interference wave arrival direction estimation unit that estimates the arrival direction of the interference wave using the output signal of the reception unit, and outputs of the interference wave arrival direction estimation unit An interference wave angular spread estimation unit that estimates an angular spread of the interference wave arrival direction by using the interference wave directivity of the array antenna toward the arrival direction of the arrival wave having the maximum power and the direction of the arrival wave having the maximum power Generation for generating an array weight that forms a directivity null with a width corresponding to the interference wave angular spread in the arrival direction of the interference wave when the arrival direction of the interference wave and the interference wave are not the same When adaptive antenna device comprising a transmitting beam forming unit for multiplying said array weight to the transmission signal, and a transmission unit for transmitting an output of the transmit beam forming unit from said array antenna.

An array antenna composed of a plurality of antenna elements; a receiving unit that performs quadrature detection after frequency conversion of an incoming wave signal received by each antenna element of the array antenna; and a plurality of arrivals using an output signal of the receiving unit A direction-of-arrival estimator for estimating the arrival direction of the waves and their power, and selecting a maximum power wave from the plurality of arriving waves using the output of the direction-of-arrival estimator, An angular spread estimation unit that estimates an angular spread with respect to an incoming wave of power within a predetermined value with respect to a power wave; and an interference wave arrival direction estimation unit that estimates an arrival direction of an interference wave using an output signal of the reception unit; An interference wave angular spread estimation unit that estimates an angular spread of the interference wave arrival direction using an output of the interference wave arrival direction estimation unit, and an arrival wave having a power within a predetermined value with respect to the maximum power wave. Do In this case, the directivity of the array antenna is directed to the direction in which the angular spread is minimum, and if not, the directivity of the array antenna is directed to the direction of the maximum power wave. If they are not the same, a weight generation unit that generates an array weight that forms a directivity null having a width corresponding to the interference wave angular spread in the direction of arrival of the interference wave, and a transmission beam that multiplies the transmission signal by the array weight An adaptive antenna apparatus comprising: a forming unit; and a transmitting unit that transmits the output of the transmission beam forming unit from the array antenna.

The adaptive antenna device according to claim 1 or 3, wherein the arrival direction estimation algorithm in the main wave direction estimation unit is switched according to the magnitude of the angular spread of the arrival wave.

The adaptive antenna apparatus according to claim 2, 4, 7, or 9 , wherein the arrival direction estimation algorithm in the arrival direction estimation unit is switched according to the magnitude of the angular spread of the arrival wave.

The adaptive antenna device according to claim 6, wherein the arrival direction estimation algorithm in the interference wave arrival direction estimation unit is switched according to the angular spread of the interference wave.

13. The adaptive antenna device according to claim 10, 11 or 12 , wherein when the angular spread is larger than a predetermined value, the direction-of-arrival estimation algorithm is switched to an algorithm to which a spatial smoothing process is added.