JP4178765B2

JP4178765B2 - Mobile communication system, communication control method thereof, and base station and mobile station used therefor

Info

Publication number: JP4178765B2
Application number: JP2001158017A
Authority: JP
Inventors: 彰久後川; 孝二郎濱辺
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 1998-04-07
Filing date: 2001-05-28
Publication date: 2008-11-12
Anticipated expiration: 2018-11-02
Also published as: JP2002026811A

Description

【０００１】
【発明の属する技術分野】
本発明は移動通信システム及びその通信制御方法並びにそれに用いる基地局及び移動局に関し、特に基地局から移動局へ送信される通信フレーム中に通信データのない空き時間を設けこの空き時間を利用して、移動局側で、例えば、異周波キャリアの無線回線品質測定等の処理を行うようにした移動通信方式に関するものである。
【０００２】
【従来の技術】
移動通信システムでは、セルと呼ばれる通信サービス領域の単位を設け、複数のセルの集合体として広域サービスエリアを実現している。セルは、一つの基地局がカバーする範囲として定義される。また、各基地局は多くのユーザ信号等を収容するために、通信に利用可能な周波数キャリアを複数用意している。例えば、図８の周波数配置において、周波数キャリア４０１，４０２は、同一基地局が同時に用いることができる。
【０００３】
通信中の移動局がサービスエリア内を移動すると、現在のセルから新しい隣のセルへの移動が生じ、接続する基地局を切り替えるために無線回線の切り替えが行われる。例えば、図９において、回線６０１から回線６１１への切り替えのような場合である。このように、接続する無線回線の切り替えをハンドオーバという。無線回線の切り替えは、移動局の移動がない場合でも生じる。例えば、接続中の回線の品質が悪い場合や、通信速度を変更したいが現在接続中の回線では実現不可能な場合等があり、複数のキャリアを有する同一基地局の無線回線間（図９の回線６０１と６０３間）や、複数の基地局（セル）が同時にその地点のサービスをカバーしている場合の当該複数基地局の無線回線間においても生じる。
【０００４】
また、切り替え前の無線回線において通信に用いていたキャリアの周波数と、切り替え後の無線回線において通信に用いるキャリアの周波数とが異なる場合、特に異周波ハンドオーバという。異周波ハンドオーバを実現するためには、切り替え対象として無線回線品質のよい周波数キャリアを選ぶために、回線品質測定を行う必要がある。
【０００５】
従来、ＴＤＭＡのように自局が送受信を行わない時間がある場合は、その空きスロット時間を利用して、無線周波数を現在通信中の無線周波数から観測対象の周波数に切り替えて、異周波キャリアの無線回線品質測定に用いる方法がある。この方法では、通信と異周波キャリアの観測とを同時に行わないので、無線周波数の切り替え操作で対処すればよく、異周波キャリアの観測用に無線機を別に用意する必要はない。
【０００６】
一方、ＦＤＭＡやＣＤＭＡのように連続伝送を基本とする方式では、２つ以上の複数の無線機を利用し、通信に用いていない無線機で、他の周波数キャリアの無線回線品質測定に用いる方法がある。ＣＤＭＡで２つ以上の無線機を利用しない方法としては、いわゆる、スロッテッドモード（Slotted mode）が提案されている（文献１：Ｍ．Ｇｕｓｔａｆｓｓｏｎｅｔａｌ．，“ＣｏｍｐｒｅｓｓｅｄＭｏｄｅＴｅｃｈｎｉｑｕｅｓｆｏｒＩｎｔｅｒ−ＦｒｅｑｕｅｎｃｙＭｅａｓｕｒｅｍｅｎｔｓｉｎａＷｉｄｅ−ｂａｎｄＤＳ−ＣＤＭＡＳｙｓｔｅｍ，” Ｐｒｏｃｅｅｄｉｎｇｓｏｆｔｈｅ８ｔｈＰＩＭＲＣ，Ｓｅｐｔ．’９７）。これは、複数時刻に渡り拡散率を下げるか、あるいは誤り訂正符号化の符号化率を高くするいわゆるパンクチュアリングすることににより、信号を時間方向に圧縮して、拡散帯域は同一に維持しつつデータ信号のない空き時間を設ける方式である。
【０００７】
図１０はかかる空き時間を設けた場合の例を示す図であり、図中のＳ１〜Ｓｋ＋１はタイムスロットを示している。図１０を参照すると、期間Ｔ２において拡散率を半分にすることにより、期間Ｔ１やＴ３に比較して信号伝送速度を２倍に上げ、時間軸方向に信号を１／２に圧縮した一例を示したものである。こうして得られる空き時間Ｔ４において、無線周波数を通信中の周波数キャリアから異なる周波数キャリアに切り替え、そのキャリアの品質を測定するものである。
【０００８】
一方、送信信号に挿入された複数のパイロットブロックを使用して、チャネル推定（振幅情報及び位相情報の検出）を精度良く行い、同期検波において所要の受信品質（ビット誤り率等）を得るための信号対雑音電力比を低減する技術がある（文献２：電子情報通信学会、１９９６年８月、信学技報、ｐ．４５〜５０
「ＤＳ−ＣＤＭＡにおける複数パイロットブロックを用いる高精度チャネル推定法」）。
【０００９】
また、移動局から、パイロット信号を情報系列中に挿入して送信し、基地局において、このパイロット信号を受信して逆方向（上り）回線の品質（ＳＩＲ：信号電力対干渉電力比）を測定し、そのＳＩＲを目標値と比較しその比較結果を移動局へ報告し、それに従って移動局において順方向の送信電力を変更制御する方式がある。
【００１０】
更にはまた、このパイロット信号は順方向（下り方向）回線の送信電力の制御にも使用されている。すなわち、移動局において、基地局から送出されてきたパイロット信号を受信し順方向回線の品質を測定し、そのＳＩＲを目標値と比較しその比較結果を基地局へ報告し、それに従って基地局において順方向の送信電力を変更制御する様になっている。
【００１１】
【発明が解決しようとする課題】
しかしながら、上述したスロッテッドモード（Slotted mode）の場合、基地局においては、空き時間中は逆方向（上り）回線の送信電力を制御するための情報を送信することができないので、逆方向回線の特性が劣化するという問題がある。図９の例を用いて具体的に述べると、基地局６００に接続している移動局６２０は下り回線として回線６０１を、上り回線として回線６０２を用いて通信を行っているとする。
【００１２】
回線６０１の送信信号構成は、例えば図１１のようになっている。（ａ）に示す様に、
ｍ個のフレームＦ１〜Ｆｍからなるスーパフレームがあり、各フレームＦｉは、（ｂ）に示す如く、一定の時間単位の間隔でセグメント化されたスロットＳ１〜Ｓｎからなっている。そして、各スロットＳｊは（ｃ）〜（ｅ）の３種の形式がある。（ｃ）では、スロットの先頭から順に、パイロット信号ＰＬ、送信電力制御信号ＴＰＣ（TransmissionPower Control ）、送信レート情報ＲＩ（Rate Information）、送信データＤ１が配置されている。
【００１３】
（ｄ）では、スロットの先頭から順に、パイロット信号ＰＬ、送信レート情報ＲＩ、送信データＤ１、送信電力制御信号ＴＰＣ、送信データＤ２が配置されている。（ｅ）では、スロットの先頭から順に、送信レート情報ＲＩ、送信データＤ１、送信電力制御信号ＴＰＣ、送信データＤ２、パイロット信号ＰＬが配置されている。
【００１４】
パイロット信号ＰＬは、上述した様に、同期検波及び品質測定用の信号であり、送信電力制御信号ＴＰＣは逆方向回線（例えば、上り回線６０２）の送信電力制御用情報である。このとき、回線６０１が異周波キャリア測定モードに入り、図１０の空き時間Ｔ４に入ると、逆方向回線６０２の送信電力制御用情報が回線６０１で送信されなくなるため、移動局６２０の送信電力が適切なレベルからずれていくことにより、逆方向回線６０２の特性が劣化する。この劣化は、空き時間Ｔ４が長いほど大きい。
【００１５】
また、移動局において、複数のパイロットシンボルを使用した受信を行う場合に、空き時間Ｔ４の存在により前後のパイロットシンボルを使用した受信ができなくなって、受信品質の劣化を招来する。また、基地局からのパイロット信号の送信がないことにより、移動局でのＳＩＲ測定が行われず、結果として基地局において、順方向（下り）回線の送信電力制御ができないという欠点もある。
【００１６】
本発明の目的は、スロッテッドモードにおける空き時間での逆方向回線の送信電力制御特性の劣化を小さく抑えるようにした移動通信システム及びその通信制御方法並びにそれに用いる基地局及び移動局を提供することである。
【００１７】
本発明の他の目的は、移動局において、複数のパイロットシンボルを使用した受信を行う場合に、前後のパイロットシンボルを使用した受信ができなくなることによる受信品質の劣化を抑えるするようにした移動通信システム及びその通信制御方法並びにそれに用いる基地局及び移動局を提供することである。
【００１８】
本発明の更に他の目的は、基地局からのパイロット信号の送信がなくなることよって順方向回線の送信電力制御ができなくなることを防止した移動通信システム及びその通信制御方法並びにそれに用いる基地局及び移動局を提供することである。
【００１９】
【課題を解決するための手段】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムであって、
前記基地局は、
前記通信フレーム中に前記空き時間を設ける手段と、この空き時間においても前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含む第１の制御信号を挿入して送信する送信制御手段とを含むことを特徴とする移動通信システムが得られる。
そして、前記送信制御手段は、前記パイロット信号を予め定められた時間間隔で挿入することを特徴とし、前記時間間隔は通信時の前記第１の制御信号の時間間隔よりも長く設定されていることを特徴とする。また、前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含む第２制御信号の直後から前記空き時間を設けることを特徴とする。
【００２０】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムであって、
前記基地局は、
前記通信フレーム中に前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含む第２の制御信号を挿入する手段と、前記空き時間を前記第２の制御信号の直後から設けて送信する送信制御手段とを含むことを特徴とする移動通信システムが得られる。
【００２１】
前記送信制御手段は、前記空き時間の終了直後に前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含む第３の制御信号を送信することを特徴とし、また前記第１の制御信号は、逆方向回線用の送信電力制御情報を含むことを特徴とする。前記第２の制御信号は、逆方向回線用の送信電力制御情報を含むことを特徴とし、前記第３の制御信号は、逆方向回線用の送信電力制御情報を含むことを特徴とする。
【００２２】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムであって、
前記基地局は、
前記空き時間を通信品質を維持するための第２の制御信号の直後から設ける手段と、前記空き時間の終了直後に通信品質を維持するための第３の制御信号を送信する送信制御手段とを含み、
前記２及び第３の制御信号が通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号であることを特徴とする移動通信システムが得られる。
【００２３】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムであって、
前記基地局は、
前記空き時間を通信品質を維持するための第２の制御信号の直後から設ける手段と、前記空き時間の終了直後に通信品質を維持するための第３の制御信号を送信する送信制御手段とを含み、
前記２の制御信号が逆方向回線用の送信電力制御情報であり、前記第３の制御信号が通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号であることを特徴とする移動通信システムが得られる。
【００２４】
また、所定の周期で前記空き時間を設ける通信モードに切り替えることを特徴とし、基地局から移動局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とする。また、基地局において観測した回線品質状態に応じて移動局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とする。更に、基地局において観測した輻輳状態に応じて移動局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とする。更に、移動局から基地局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とする。また、移動局において観測した回線品質状態に応じて基地局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とする。
【００２５】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける通信制御方法であって、
前記基地局において、
前記通信フレーム中に前記空き時間を設けるステップと、この空き時間においても前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含む第１の制御信号を挿入して送信するステップとを含むことを特徴とする通信制御方法が得られる。
そして、前記送信するステップは、前記第１の制御信号を予め定められた時間間隔で挿入することを特徴とし、前記時間間隔は通信時の前記第１の制御信号の時間間隔よりも長く設定されていることを特徴とする。また、前記空き時間を設けるステップは、前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含む第２の制御信号の直後から前記空き時間を設けるようにしたことを特徴とする。
【００２６】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける通信制御方法であって、
前記基地局において、
前記通信フレーム中に前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含む第２の制御信号を挿入するステップと、前記空き時間を前記第２の制御信号の直後から設けて送信するステップとを含むことを特徴とする通信制御方法が得られる。
【００２７】
前記空き時間の終了直後に、前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含む第３の制御信号を送信することを特徴とする。また前記第１の制御信号は、逆方向回線用の送信電力制御情報をも含むことを特徴とし、前記第２の制御信号は、逆方向回線用の送信電力制御情報をも含むことを特徴とし、また前記第３の制御信号は、逆方向回線用の送信電力制御情報をも含むことを特徴とする。
【００２８】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける通信制御方法であって、
前記基地局において、
前記空き時間を通信品質を維持するための第２の制御信号の直後から設けるステップと、前記空き時間の終了直後に通信品質を維持するための第３の制御信号を送信するステップとを含み、
前記２及び第３の制御信号が通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号であることを特徴とする通信制御方法が得られる。
【００２９】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける通信制御方法であって、
前記基地局において、
前記空き時間を通信品質を維持するための第２の制御信号の直後から設けるステップと、前記空き時間の終了直後に通信品質を維持するための第３の制御信号を送信するステップとを含み、
前記２の制御信号が逆方向回線用の送信電力制御情報であり、前記第３の制御信号が通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号であることを特徴とする通信制御方法が得られる。
【００３０】
所定の周期で前記空き時間を設ける通信モードに切り替えることを特徴とし、また基地局から移動局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とする。更に、基地局において観測した回線品質状態に応じて移動局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とし、また基地局において観測した輻輳状態に応じて移動局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とする。移動局から基地局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とし、また移動局において観測した回線品質状態に応じて基地局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とする。
【００３１】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける基地局であって、
前記通信フレーム中に前記空き時間を設ける手段と、
この空き時間においても前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含む第１の制御信号を挿入して送信する送信制御手段とを含むことを特徴とする基地局が得られる。
そして、前記送信制御手段は、前記第１の制御信号を予め定められた時間間隔で挿入することを特徴とし、また前記時間間隔は通信時の前記第１の制御信号の時間間隔よりも長く設定されていることを特徴とする。また、前記送信制御手段は、前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含む第２制御信号の直後から前記空き時間を設けることを特徴とする。
【００３２】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける基地局であって、
前記通信フレーム中に前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含む第２の制御信号を挿入する手段と、
前記空き時間を前記第２の制御信号の直後から設けて送信する送信制御手段とを含むことを特徴とする基地局が得られる。
【００３３】
そして、前記送信制御手段は、前記空き時間の終了直後に前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含む第３の制御信号を送信することを特徴とする。また、前記第１の制御信号は、逆方向回線用の送信電力制御情報を含むことを特徴とし、前記第２の制御信号は、逆方向回線用の送信電力制御情報を含むことを特徴とし、また前記第３の制御信号は、逆方向回線用の送信電力制御情報を含むことを特徴とする。
【００３４】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける基地局であって、
通信品質を維持するための第２の制御信号を挿入する手段と、
前記空き時間を前記第２の制御信号の直後から設け、前記空き時間の終了直後に第３の制御信号を送信する送信制御手段とを含み、
前記第２及び第３の制御信号が前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号であることを特徴とする基地局が得られる。
【００３５】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける基地局であって、
前記空き時間を通信品質を維持するための第２の制御信号の直後から設ける手段と、
前記空き時間の終了直後に通信品質を維持するための第３の制御信号を送信する送信制御手段とを含み、
前記２の制御信号が逆方向回線用の送信電力制御情報であり、前記第３の制御信号が通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号であることを特徴とする基地局が得られる。
そして、所定の周期で前記空き時間を設ける通信モードに切り替えることを特徴とし、また移動局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とする。また、回線品質状態に応じて移動局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とし、また輻輳状態に応じて移動局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とする。更に、前記移動局からの通知により前記空き時間を設ける通信モードに切り替えることを特徴とする。
【００３６】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける移動局であって、
前記空き時間に送信された通信品質を維持するための第１の制御信号を受信し、この第１の制御信号に基き受信品質を測定する品質測定手段と、
この受信品質に従って順方向の送信電力制御情報を生成して送信する送信手段とを含むことを特徴とする移動局が得られる。
【００３７】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける移動局であって、
前記空き時間に送信された通信品質を維持するための第１の制御信号を受信する手段と、
この第１の制御信号を用いて通信データを復調する復調手段とを含むことを特徴とする移動局が得られる。
【００３８】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける移動局であって、
前記空き時間に送信された通信品質を維持するための第１の制御信号を受信する手段と、
この第１の制御信号に従って逆方向の送信電力を制御する手段とを含むことを特徴とする移動局が得られる。
【００３９】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける移動局であって、
前記空き時間の直前に設けられた通信品質を維持するための第２の制御信号を受信する手段と、
この制御信号に基き受信品質を測定する品質測定手段と、
この受信品質に従って順方向の送信電力制御情報を生成して送信する送信手段とを含むことを特徴とする移動局が得られる。
【００４０】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける移動局であって、
前記空き時間の直前に設けられた通信品質を維持するための第２の制御信号を受信する手段と、
この制御信号を用いて通信データを復調する復調手段とを含むことを特徴とする移動局が得られる。
【００４１】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける移動局であって、
前記空き時間の直前に設けられた通信品質を維持するための第２の制御信号を受信する手段と、
この第２の制御信号に基き逆方向の送信電力を制御する手段とを含むことを特徴とする移動局が得られる。
【００４２】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける移動局であって、
前記空き時間の直前に設けられた通信品質を維持するための第２の制御信号を受信すると共に、前記空き時間の直後に通信品質を維持するための第３の制御信号を受信する手段と、
これ等第２若しくは第３の制御信号に基き受信品質を測定する品質測定手段と、
この受信品質に従って順方向の送信電力制御情報を生成して送信する送信手段とを含むことを特徴とする移動局が得られる。
【００４３】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける移動局であって、
前記空き時間の直前に設けられた通信品質を維持するための第２の制御信号を受信すると共に、前記空き時間の直後に通信品質を維持するための第３の制御信号を受信する手段と、
これ等第２若しくは第３の制御信号を用いて通信データを復調する復調手段とを含むことを特徴とする移動局が得られる。
【００４４】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける移動局であって、
前記空き時間の直前に設けられた通信品質を維持するための第２の制御信号を受信すると共に、前記空き時間の直後に通信品質を維持するための第３の制御信号を受信する手段と、
この第３の制御信号に基き受信品質を測定する品質測定手段と、
この受信品質に従って順方向の送信電力制御情報を生成して送信する送信手段と、
前記第２の制御信号に基づいて逆方向の送信電力を制御する手段とを含むことを特徴とする移動局が得られる。
【００４５】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける移動局であって、
前記空き時間の直前に設けられた通信品質を維持するための第２の制御信号を受信すると共に、前記空き時間の直後に通信品質を維持するための第３の制御信号を受信する手段と、
この第３の制御信号を用いて通信データを復調する復調手段と、
前記第２の制御信号に基づいて逆方向の送信電力を制御する手段とを含むことを特徴とする移動局が得られる。
【００４６】
本発明によれば、基地局と移動局とを含み、前記基地局から前記移動局への順方向回線の通信フレーム中に通信データを時間軸方向に圧縮して生じた空き時間を設けるようにした移動通信システムにおける移動局であって、
前記空き時間の直前に設けられた通信品質を維持するための第２の制御信号を受信すると共に、前記空き時間の直後に通信品質を維持するための第３の制御信号を受信する手段と、
この第３の制御信号を用いて通信データを復調する復調手段と、
第３の制御信号に基き受信品質を測定する品質測定手段と、
この受信品質に従って順方向の送信電力制御情報を生成して送信する送信手段と、
前記第２の制御信号に基づいて逆方向の送信電力を制御する手段とを含むことを特徴とする移動局が得られる。
【００４７】
そして、前記第１の制御信号は、前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含むことを特徴とし、また前記第２の制御信号は、前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含むことを特徴とする。また、前記第３の制御信号は、前記通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号を含むことを特徴とし、前記第１の制御信号は、逆方向回線用の送信電力制御情報をも含むことを特徴とする。また、前記第２の制御信号は、逆方向回線用の送信電力制御情報をも含むことを特徴とする。
【００４８】
また、前記第１の制御信号は、通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号、及び逆方向回線用の送信電力制御情報をも含むことを特徴とする。前記第２の制御信号は、通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号、及び逆方向回線用の送信電力制御情報をも含むことを特徴とし、前記第３の制御信号は、通信データの復調または順方向回線用の送信電力制御に使用されるパイロット信号、及び逆方向回線用の送信電力制御情報をも含むことを特徴とする。また、所定の周期で前記空き時間を設ける通信モードに切り替えることを特徴とし、基地局からの通知により前記空き時間を設ける通信モードに切り替えることを特徴とする。
また、基地局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とし、回線品質状態に応じて基地局に通知を行うことにより前記空き時間を設ける通信モードに切り替えることを特徴とする。
【００４９】
【発明の実施の形態】
以下に本発明の実施の形態を示す。図１は本発明の実施の形態の基地局のブロックである。入力送信データは誤り訂正符号化部１へ入力されて誤り訂正符号化され、セグメント化部２へ供給される。生成されたセグメントであるスロットの各々には、図１１の（ｃ）〜（ｅ）に夫々示した制御信号であるパイット信号ＰＬ、送信電力制御信号ＴＰＣ及び送信レート情報ＲＩ等が規定の位置に挿入される。セグメント化部２の出力は変調部３にて変調され、拡散回路４及びパワーアンプ５を経て、送受信共用回路６からアンテナ７へと供給され送信されることになる。
【００５０】
後述する移動局からの受信信号はアンテナ７、送受信共用回路６を介して逆拡散回路８へ供給され、復調部９にて復調されて出力される。復調部９の出力からパイロット信号抽出部１０にて制御信号のうちのパイロット信号が抽出され、ＳＩＲ測定部１１にて上り回線のＳＩＲ測定がなされる。ＴＰＣ信号生成部１２において、この測定ＳＩＲ値と目的とする値とが比較されこの比較結果に従って上り回線のための送信電力制御情報ＴＰＣが生成される。この送信電力制御情報ＴＰＣは制御信号挿入部１３へ送出されて、パイロット信号等の他の制御情報と共に各セグメントに夫々挿入される。一方、復調部９の出力からＴＰＣ信号抽出部１４にて下り回線のための送信電力制御情報ＴＰＣが抽出され、この情報ＴＰＣに応じてパワーアンプ５の利得制御がなされる。
【００５１】
ここで、図１０に示した空き時間Ｔ４を生成する方法としては、前述した様に、パンクチュアリングによる方法と、拡散率を低くする方法とがある。前者の方法は、誤り訂正符号化部１にて、例えば、１６スロット分のデータを１５スロット分のデータに間引く方式である。これにより１スロット分の空き時間が生ずることになる。後者の拡散率を低くする方法は、セグメント化部２において、例えば、１６スロット分のデータを８セグメントとして拡散率を１／２にすることで、伝送速度を２倍に上げ時間軸方向に信号を１／２に圧縮する方式であり、比較的長い空き時間が生成可能である。この空き時間を利用して、移動局では、異周波キャリア品質測定を行ったり、他の種々の処理が行われるが、本発明では、この空き時間においても、制御信号挿入部１３により制御信号を挿入するのである。
【００５２】
図２は図１に示した基地局の動作の概略を示すフローチャートである。図２を参照すると、先ず、送信データの誤り訂正符号化が行われ（ステップＳ１）、セグメント化がなされる（ステップＳ２）が、このとき、一定周期で空き時間の生成が行われるものとする（ステップＳ３）。通常のデータ送信期間における各セグメントに制御信号の挿入が実行され（ステップＳ４，Ｓ１０）、空き時間、空き時間の直前、または空き時間の直後にも制御信号の挿入が行われる（ステップＳ４，Ｓ５）。そして、送信電力制御を行いつつ送信される（ステップＳ６）。
【００５３】
一方、受信データより制御信号が抽出され（ステップＳ７）、制御信号中のパイロット信号によりＳＩＲ測定がなされる（ステップＳ８）。この測定結果と目的値とが比較されてこの比較結果にしたがった上り回線のための送信電力制御情報ＴＰＣが生成され（ステップＳ９）、パイロット信号等の他の制御信号と共に、各セグメント並びに空き時間に夫々挿入される（ステップＳ５，１０）。また、ステップＳ７で抽出された制御信号中の下り回線のための送信電力制御情報ＴＰＣに従って、送信電力制御が行われることになる（ステップＳ６）。
【００５４】
この場合の空き時間に制御信号を挿入する種々の例を図３〜５に夫々示す。図３の例では、主に空き時間Ｔ４が比較的長い場合に有効であり、スロッテッドモードにおいて拡散率を変えることにより空き時間を確保する場合に相当する。空き時間が比較的長い場合には、一つの連続した空き時間とせずに、例えば、空き時間にて行うべき処理が、例えば、異周波キャリア品質測定の場合には、それに必要最小限の時間の小ブロックＴ41，Ｔ42に細分し、これ等小ブロック同士の間の時間に、制御信号１０１を送信するようにしたものである。
【００５５】
図３では、空き時間Ｔ４中の制御信号伝送が１回の場合が示されているが、複数回、制御信号伝送を行うようにしてもよいのは明らかである。また、そのとき、空き時間Ｔ４中に挿入する複数の制御信号間の送信間隔は、通常の送信モード中の同種の制御信号の送信間隔よりも長く設定してもよい。
【００５６】
図４の例では、空き時間Ｔ４が比較的に短く、これ以上細分しては細分化した時間では、その間に実行すべき、例えば、異周波キャリア品質測定が困難となる場合に適用される。主に、スロッテッドモードにおいて、パンクチュアリングにより空き時間を確保する場合が該当する。この例では、空き時間Ｔ４に入る前に、異周波キャリア品質測定モード中の情報信号伝送の直後の制御信号１０１まで送信した後、空き時間に入るようにしたものである。制御信号１０１で上り（逆方向）回線の送信電力が実施されるので、従来のように情報信号伝送の直後に空き時間に入るより、上り（逆方向）回線の特性は向上する。
【００５７】
本例では、図１１（ｃ），（ｄ），（ｅ）の場合の様に、空き時間Ｔ４が開始するスロットの先頭付近に一部または全ての制御信号が存在するスロットの形式の場合に効果的である。本例では、空き時間Ｔ４が短い場合であるが、空き時間が長い場合でも、図４に示した様に、それを細分化せずに空き時間に入る前に次の制御信号まで送信した後、異周波キャリア品質測定に入るようにしてもよいのは明らかである。
【００５８】
図５の例では、空き時間Ｔ４の直後に制御信号１０１を挿入している。この例では、図１１（ｅ）の場合の様に、空き時間Ｔ４が終了するスロットの末尾に一部または全ての制御信号が存在するスロット形式の場合に効果的である。本例でも、制御信号を一定時間間隔で挿入しても良いことは勿論である。また、本例において、同時に、図４のように空き時間Ｔ４の直前にも制御信号伝送を行い、制御信号伝送を行ってから異周波キャリアの受信を行う移動局に対する通信データの送信を停止しても良いことも勿論である。
【００５９】
図６は本発明の実施の形態における移動局のブロック図である。図６を参照すると、アンテナ２１からの受信信号は送受信共用回路２２を経て逆拡散回路２３へ入力されて逆拡散処理が行われ、復調部２４で復調されて出力される。一方、入力送信データはセグメント化部２５にてセグメント化されて変調部２６へ入力され、拡散回路２７及びパワーアンプ２８を介して送受信共用回路２２々供給され、アンテナ２１から送信される。
【００６０】
パイロット信号抽出部２９において、復調部２４の信号からパイロット信号が抽出され、ＳＩＲ測定部３０へ送出される。このＳＩＲ測定部３０において、下り（順方向）回線のＳＩＲが測定され、ＴＰＣ信号生成部３１において、この測定値と目標値とが比較され、この比較結果が、下り（順方向）送信電力制御信号ＴＰＣとして、他の制御信号であるパイロット信号等と共に、制御信号挿入部３２により各セグメントに挿入されるのである。
【００６１】
一方、ＴＰＣ信号抽出部３３において、復調部２４の信号から上り（逆方向）送信電力制御信号ＴＰＣが抽出され、この信号ＴＰＣに従って、パワーアンプ２８の利得制御がなされるのである。
【００６２】
図７は図６に示した移動局の動作を示す概略ブロック図である。図７を参照すると、送信データのセグメント化が行われ（ステップＳ２１）、各セグメントに制御信号が挿入される（ステップＳ２２）。そして、送信電力制御が行われつつ送信がなされる（ステップＳ２３）。
【００６３】
一方、受信データより制御信号の抽出が行われ（ステップＳ２４）、この制御信号中のパイロット信号によりＳＩＲ測定がなされる（ステップＳ２５）。このＳＩＲ測定値と目標値との比較がなされてこの比較結果に応じて、下り（順方向）送信電力制御信号ＴＰＣが生成される（ステップＳ２６）。この生成された送信電力制御信号ＴＰＣはステップＳ２２にてセグメントへ挿入される。また、受信データからの抽出制御信号中の上り（逆方向）送信制御信号ＴＰＣに従って、送信電力制御が行われて（ステップＳ２３）、上り（逆方向）送信がなされる。
【００６４】
上記例では、上り回線及び下り回線の各制御信号として、パイロット信号ＰＬ及び送信電力制御情報ＴＰＣを夫々含むものとして説明している。この場合には、両方向の送信電力の制御が可能であり、特に空き時間Ｔ４中においても、制御信号１０１としてパイロット信号ＰＬ及び送信電力制御情報ＴＰＣを含む構成とすることで、移動局では上り回線の送信電力制御がその分だけ多く実施できるので、特に上り回線の送信電力特性の劣化を抑止することができる。
【００６５】
また、他の例として、空き時間Ｔ４中における制御信号１０１として、パイロット信号ＰＬのみとすることもできる。例えば、図１１（ｃ）、（ｄ）のようにスロットの先頭にパイロット信号ＰＬが配置されている場合には、図４に示すように、情報信号伝送の直後の制御信号であるパイロット信号ＰＬまで送信した後、異周波キャリアの受信を行う移動局に対する通信データの送信を停止するようにすることができる。
【００６６】
また、図１１（ｅ）のようにスロットの末尾にパイロット信号ＰＬが配置されている場合には、図５に示すように、空き時間の終了直後に制御信号であるパイロット信号ＰＬを挿入し、そのパイロット信号から送信を開始するようにすることができる。これらの場合には、移動局は、空き時間の直前の受信データも、空き時間の直後の受信データも、前後のパイロット信号を用いて復調できることになるので、下り回線の受信品質が改善される。
【００６７】
また、これら場合には、基地局から送信されたパイロット信号ＰＬが移動局で受信されてＳＩＲ測定され、その測定結果が基地局へ報告されることで、基地局では下り回線の送信電力の制御ができることになり、結果として、下り回線の回線品質が向上するのである。そして、送信停止直前（空き時間Ｔ４の開始直前）のパイロット信号を送信することにより、移動局では、そのパイロット信号を使用してＳＩＲ測定を行い、基地局に対して送信電力制御命令を１つ多く送信することができ、下り回線の送信電力制御の効果が改善される。
【００６８】
また、空き時間の直前と直後の両方に制御信号を送信するようにしてもよい。例えば、図１１（ｅ）のスロット構成をとる場合に、空き時間の直前に挿入する制御信号を送信電力制御情報ＴＰＣ、そして、空き時間の直後に挿入する制御信号をパイロットＰＬとすることができる。この場合には、基地局は送信電力制御情報ＴＰＣを送信してから、異周波キャリアの受信を行う移動局に対する通信データの送信を停止するから、それを用いて、移動局では上り回線の送信電力制御ができるので、上り回線品質劣化を低減することができる。また、基地局はパイロットＰＬから送信を開始するから、移動局では、空き時間の直後にデータを受信するときに、そのパイロットＰＬを含む、前後のパイロット信号を用いた受信ができるようになるので、下り回線の受信品質が改善される。さらに、移動局は、空き時間の直後のパイロットＰＬを使用してＳＩＲ測定を行い、基地局に対して送信電力制御命令を１つ多く送信することができ、下り回線の品質劣化も低減することができる。
【００６９】
更に、スロッテッドモードである空き時間の生成のタイミングとしては、図２の動作フローのステップＳ３で示した様に、一定の周期でもって空き時間を生成する方法の他に、基地局または移動局が回線品質状態を監視してこの回線の品質状態に応じて空き時間を生成する方法が考えられる。例えば、基地局が移動局からの信号のフレーム誤り率などの回線品質を監視し、その値が許容値を超えた場合には、移動局に他の周波数キャリアの受信状態を測定させるための通知を行い、基地局は空き時間も設ける送信モードに入り、移動局では、その通知を受けて、その送信モードに対応した制御動作を開始する。
【００７０】
また、同様に、移動局が回線品質を監視して、回線品質が劣化した場合に基地局に通知して、基地局はその通知を受けて、空き時間を設ける送信モードに入り、移動局は同時に、そのその送信モードに対応した制御動作を開始する。更には、基地局が回線の輻輳状態を監視してこの輻輳状態に応じて空き時間を生成する方法等が考えられるものである。基地局が回線の輻輳状態を監視して空き時間を設ける送信モードに入る方法としては、基地局が自局と通信中の移動局数を監視し、その値が所定値を超えた場合には、通信中の移動局の一部に対して、他の周波数キャリアの受信状態を測定させるための通知を行い、基地局は、その通知を行った移動局に対して空き時間も設ける送信モードに入り、その通知を受けた移動局では、その送信モードに対応した制御動作を開始する方法が考えられる。
【００７１】
【発明の効果】
以上説明したように、本発明によれば、異周波キャリア品質測定等の種々の処理を行うためにデータ送信中にスロッテッドモードによる空き時間を生成して送信する通信方式において、当該空き時間にも、通信品質を維持するための制御信号を挿入する様にしているので、空き時間が長くなっても通信中の回線品質が劣化しないという効果がある。
【００７２】
すなわち、当該制御信号としてパイロット信号を用いた場合には、空き時間であっても、移動局において当該パイロット信号により下り回線品質の測定を行い、その測定結果を基地局へ報告することができるので、基地局では、この報告に従って下り回線の送信電力制御を行うことがで、よって下り回線の品質劣化が抑止される。また、移動局において、複数のパイロット信号を用いた受信をなす場合に、前後のパイロット信号を用いた受信ができなくなることによる通信品質の劣化が防止される。
【００７３】
当該制御信号としてパイロット信号の他に、上り回線の送信電力制御情報をも送信することにより、移動局は空き時間であっても、この送信電力制御情報を用いて上り回線の送信電力の制御ができるので、上り回線品質劣化の防止にもなる。
【図面の簡単な説明】
【図１】本発明の実施例における基地局のブロック図である。
【図２】図１の基地局の動作を示すフローチャートである。
【図３】本発明の実施例における制御信号挿入の一例を示す図である。
【図４】本発明の実施例における御信号挿入の他の例を示す図である。
【図５】本発明の実施例における御信号挿入の更に他の例を示す図である。
【図６】本発明の実施例における移動局のブロック図である。
【図７】図６の移動局の動作を示すフローチャートである。
【図８】周波数キャリアの配置例を示す図である。
【図９】基地局と移動局との間の回線を説明する図である。
【図１０】従来におけるスロッテッドモードにおける空き時間の例を示す図である。
【図１１】基地局からの下り回線の送信信号のフォーマット例を示す図である。
【符号の説明】
１誤り訂正符号化部
２，２５セグメント化部
３，２６変調部
４，２７拡散回路
５，２８パワーアンプ
６，２２送受信共用回路
７，２１アンテナ
８，２３逆拡散回路
９，２６復調部
１０，２９パイロット信号抽出部
１１，３０ＳＩＲ測定部
１２，３１ＴＰＣ信号生成部
１３，３２制御信号挿入部
１４，３３ＴＰＣ信号抽出部
１０１制御信号
Ｔ４空き時間[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mobile communication system, a communication control method thereof, and a base station and a mobile station used therefor, and in particular, a free time without communication data is provided in a communication frame transmitted from the base station to the mobile station, and the free time is used. The present invention relates to a mobile communication system in which processing such as measurement of radio channel quality of different frequency carriers is performed on the mobile station side.
[0002]
[Prior art]
In a mobile communication system, a unit of a communication service area called a cell is provided, and a wide area service area is realized as an aggregate of a plurality of cells. A cell is defined as the range covered by one base station. Each base station prepares a plurality of frequency carriers that can be used for communication in order to accommodate many user signals and the like. For example, in the frequency arrangement of FIG. 8, the frequency carriers 401 and 402 can be used simultaneously by the same base station.
[0003]
When a mobile station in communication moves within the service area, a movement from the current cell to a new neighboring cell occurs, and a radio line is switched to switch a base station to be connected. For example, in FIG. 9, this is a case of switching from the line 601 to the line 611. In this way, switching of a wireless line to be connected is called handover. Wireless line switching occurs even when the mobile station is not moving. For example, there are cases where the quality of the connected line is poor, or when it is desired to change the communication speed but this is not possible with the currently connected line, between the wireless lines of the same base station having a plurality of carriers (see FIG. 9). This also occurs between the wireless lines of the plurality of base stations when a plurality of base stations (cells) simultaneously cover the service at that point.
[0004]
In addition, when the frequency of the carrier used for communication in the radio channel before switching is different from the frequency of the carrier used for communication in the radio channel after switching, this is called a different frequency handover. In order to implement a different frequency handover, it is necessary to perform channel quality measurement in order to select a frequency carrier with good radio channel quality as a switching target.
[0005]
Conventionally, when there is a time during which the local station does not transmit / receive as in TDMA, the radio frequency is switched from the radio frequency currently being communicated to the frequency to be observed using the idle slot time, and the different frequency carrier There are methods used for wireless channel quality measurement. In this method, since communication and observation of different frequency carriers are not performed at the same time, it is only necessary to deal with radio frequency switching operations, and there is no need to prepare a separate radio for observation of different frequency carriers.
[0006]
On the other hand, in a method based on continuous transmission, such as FDMA and CDMA, a method using two or more wireless devices and measuring the wireless channel quality of other frequency carriers using a wireless device not used for communication. There is. As a method of not using two or more radios in CDMA, a so-called slotted mode has been proposed (Reference 1: M. Gustafson et al., “Compressed Mode Techniques for Inter-Frequency Measurements in”. a Wide-band DS-CDMA System, “Proceedings of the 8th PIMRC, Sept. '97). This is because the signal is compressed in the time direction by lowering the spreading factor over a plurality of times, or by so-called puncturing to increase the coding rate of error correction coding, and the spreading band is kept the same. However, this is a method of providing a free time without a data signal.
[0007]
FIG. 10 is a diagram showing an example in which such a free time is provided, and S1 to Sk + 1 in the figure indicate time slots. Referring to FIG. 10, there is shown an example in which the signal transmission rate is doubled compared to the periods T1 and T3 by halving the spreading factor in the period T2, and the signal is compressed to 1/2 in the time axis direction. It is a thing. In the free time T4 thus obtained, the radio frequency is switched from the frequency carrier in communication to a different frequency carrier, and the quality of the carrier is measured.
[0008]
On the other hand, using a plurality of pilot blocks inserted into the transmission signal, channel estimation (detection of amplitude information and phase information) is performed with high accuracy, and in order to obtain the required reception quality (bit error rate, etc.) in synchronous detection There is a technique for reducing the signal-to-noise power ratio (Reference 2: IEICE, August 1996, IEICE Technical Report, p. 45-50).
"High-accuracy channel estimation method using multiple pilot blocks in DS-CDMA").
[0009]
Also, a pilot signal is inserted into an information sequence from a mobile station and transmitted, and the base station receives the pilot signal and measures the quality of the reverse (uplink) channel (SIR: signal power to interference power ratio). Then, there is a method in which the SIR is compared with a target value, the comparison result is reported to the mobile station, and the forward transmission power is changed and controlled in the mobile station accordingly.
[0010]
Furthermore, this pilot signal is also used for controlling transmission power of the forward (downward) line. That is, in the mobile station, the pilot signal transmitted from the base station is received, the quality of the forward link is measured, the SIR is compared with the target value, the comparison result is reported to the base station, and the base station accordingly The forward transmission power is changed and controlled.
[0011]
[Problems to be solved by the invention]
However, in the case of the above-described slotted mode, the base station cannot transmit information for controlling the transmission power of the reverse (uplink) line during the idle time. There is a problem that characteristics deteriorate. Specifically, it is assumed that the mobile station 620 connected to the base station 600 performs communication using the line 601 as a downlink and the line 602 as an uplink.
[0012]
The transmission signal configuration of the line 601 is, for example, as shown in FIG. As shown in (a),
There is a super frame composed of m frames F1 to Fm, and each frame Fi is composed of slots S1 to Sn segmented at regular time unit intervals as shown in FIG. Each slot Sj has three types (c) to (e). In (c), a pilot signal PL, a transmission power control signal TPC (Transmission Power Control), transmission rate information RI (Rate Information), and transmission data D1 are arranged in order from the head of the slot.
[0013]
In (d), a pilot signal PL, transmission rate information RI, transmission data D1, transmission power control signal TPC, and transmission data D2 are arranged in order from the beginning of the slot. In (e), transmission rate information RI, transmission data D1, transmission power control signal TPC, transmission data D2, and pilot signal PL are arranged in order from the head of the slot.
[0014]
As described above, pilot signal PL is a signal for synchronous detection and quality measurement, and transmission power control signal TPC is information for transmission power control of a reverse link (for example, uplink 602). At this time, when the line 601 enters the different frequency carrier measurement mode and the idle time T4 in FIG. 10 is entered, the transmission power control information of the reverse line 602 is not transmitted on the line 601, so the transmission power of the mobile station 620 is reduced. By deviating from an appropriate level, the characteristics of the reverse link 602 deteriorate. This deterioration is greater as the idle time T4 is longer.
[0015]
Further, when the mobile station performs reception using a plurality of pilot symbols, reception using the preceding and succeeding pilot symbols cannot be performed due to the existence of the idle time T4, resulting in deterioration of reception quality. Further, since there is no transmission of a pilot signal from the base station, SIR measurement is not performed at the mobile station, and as a result, there is a disadvantage that transmission power control of the forward (downlink) line cannot be performed at the base station.
[0016]
An object of the present invention is to provide a mobile communication system, a communication control method therefor, and a base station and a mobile station used therefor, in which deterioration of transmission power control characteristics of a reverse link in idle time in a slotted mode is suppressed to a minimum. It is.
[0017]
Another object of the present invention is to provide mobile communication that suppresses deterioration of reception quality due to the fact that reception using a plurality of pilot symbols becomes impossible when reception is performed in a mobile station. A system, a communication control method thereof, and a base station and a mobile station used therefor are provided.
[0018]
Still another object of the present invention is to provide a mobile communication system, a communication control method therefor, and a base station and mobile used therefor that prevent transmission power control of the forward link from being lost due to the absence of pilot signal transmission from the base station. Is to provide a station.
[0019]
[Means for Solving the Problems]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile communication system,
The base station
Means for providing the idle time in the communication frame, and transmitting the first control signal including a pilot signal used for demodulation of the communication data or transmission power control for the forward link even in the idle time A mobile communication system including a transmission control means for performing the transmission.
The transmission control means inserts the pilot signal at a predetermined time interval, and the time interval is set longer than the time interval of the first control signal during communication. It is characterized by. The idle time is provided immediately after the second control signal including a pilot signal used for demodulation of the communication data or transmission power control for the forward link.
[0020]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile communication system,
The base station
Means for inserting a second control signal including a pilot signal used for demodulation of the communication data or transmission power control for the forward link in the communication frame; and the idle time immediately after the second control signal. The mobile communication system is characterized by including transmission control means for providing and transmitting data.
[0021]
The transmission control means transmits a third control signal including a pilot signal used for demodulation of the communication data or transmission power control for a forward link immediately after the idle time ends, and The first control signal includes transmission power control information for the reverse link. The second control signal includes transmission power control information for a reverse link, and the third control signal includes transmission power control information for a reverse link.
[0022]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile communication system,
The base station
Means for providing the idle time immediately after a second control signal for maintaining communication quality; and transmission control means for transmitting a third control signal for maintaining communication quality immediately after the idle time ends. Including
A mobile communication system is obtained in which the second and third control signals are pilot signals used for demodulation of communication data or transmission power control for a forward link.
[0023]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile communication system,
The base station
Means for providing the idle time immediately after a second control signal for maintaining communication quality; and transmission control means for transmitting a third control signal for maintaining communication quality immediately after the idle time ends. Including
The second control signal is transmission power control information for a reverse line, and the third control signal is a pilot signal used for demodulation of communication data or transmission power control for a forward line. Mobile communication system is obtained.
[0024]
In addition, the communication mode is characterized in that the communication mode is set to provide the idle time at a predetermined cycle, and the communication mode is set to provide the idle time by notifying the mobile station from the base station. In addition, the mobile station is switched to a communication mode that provides the idle time by notifying the mobile station according to the channel quality state observed in the base station. Furthermore, the mobile station is switched to a communication mode that provides the idle time by notifying the mobile station according to the congestion state observed in the base station. Further, the mobile station switches to a communication mode that provides the idle time by notifying the base station. Further, the communication mode is characterized by switching to the communication mode for providing the idle time by notifying the base station according to the channel quality state observed in the mobile station.
[0025]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A communication control method in a mobile communication system, comprising:
In the base station,
The step of providing the idle time in the communication frame and the transmission by inserting a first control signal including a pilot signal used for demodulation of the communication data or transmission power control for the forward link even in the idle time A communication control method characterized by comprising the steps of:
The transmitting step includes inserting the first control signal at a predetermined time interval, and the time interval is set longer than the time interval of the first control signal during communication. It is characterized by. In the step of providing the idle time, the idle time is provided immediately after the second control signal including a pilot signal used for demodulation of the communication data or transmission power control for the forward link. Features.
[0026]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A communication control method in a mobile communication system, comprising:
In the base station,
Inserting a second control signal including a pilot signal used for demodulating the communication data or transmitting power control for a forward link into the communication frame; and setting the idle time immediately after the second control signal. The communication control method is characterized in that it includes the step of providing and transmitting.
[0027]
Immediately after the end of the idle time, a third control signal including a pilot signal used for demodulation of the communication data or transmission power control for a forward link is transmitted. The first control signal also includes transmission power control information for the reverse link, and the second control signal also includes transmission power control information for the reverse link. In addition, the third control signal includes transmission power control information for the reverse link.
[0028]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A communication control method in a mobile communication system, comprising:
In the base station,
Providing the idle time immediately after a second control signal for maintaining communication quality, and transmitting a third control signal for maintaining communication quality immediately after the idle time ends,
The communication control method is characterized in that the second and third control signals are pilot signals used for demodulation of communication data or transmission power control for a forward link.
[0029]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A communication control method in a mobile communication system, comprising:
In the base station,
Providing the idle time immediately after a second control signal for maintaining communication quality, and transmitting a third control signal for maintaining communication quality immediately after the idle time ends,
The second control signal is transmission power control information for a reverse line, and the third control signal is a pilot signal used for demodulation of communication data or transmission power control for a forward line. A communication control method is obtained.
[0030]
Switching to a communication mode in which the idle time is provided at a predetermined cycle, and switching to a communication mode in which the idle time is provided by notifying the mobile station from a base station. Further, the mobile station is switched to a communication mode in which the idle time is provided by notifying the mobile station according to the line quality state observed at the base station, and is notified to the mobile station according to the congestion state observed at the base station. By switching to a communication mode that provides the idle time. The mobile station is switched to a communication mode that provides the idle time by notifying the base station, and the idle time is provided by notifying the base station according to the channel quality state observed in the mobile station. It is characterized by switching to a communication mode.
[0031]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A base station in a mobile communication system,
Means for providing the idle time in the communication frame;
And a transmission control means for inserting and transmitting a first control signal including a pilot signal used for demodulation of the communication data or transmission power control for a forward link even in this idle time. A station is obtained.
The transmission control means inserts the first control signal at a predetermined time interval, and the time interval is set longer than the time interval of the first control signal during communication. It is characterized by being. The transmission control means may provide the idle time immediately after a second control signal including a pilot signal used for demodulation of the communication data or transmission power control for a forward link.
[0032]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A base station in a mobile communication system,
Means for inserting a second control signal including a pilot signal used for demodulation of the communication data or transmission power control for a forward link in the communication frame;
And a transmission control unit configured to transmit the idle time immediately after the second control signal.
[0033]
The transmission control means transmits a third control signal including a pilot signal used for demodulating the communication data or transmitting power control for a forward link immediately after the idle time ends. . Further, the first control signal includes transmission power control information for a reverse link, and the second control signal includes transmission power control information for a reverse link, The third control signal includes transmission power control information for the reverse link.
[0034]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A base station in a mobile communication system,
Means for inserting a second control signal for maintaining communication quality;
Transmission control means for providing the idle time immediately after the second control signal, and transmitting a third control signal immediately after the idle time ends,
A base station is obtained in which the second and third control signals are pilot signals used for demodulation of the communication data or transmission power control for a forward link.
[0035]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A base station in a mobile communication system,
Means for providing the idle time immediately after the second control signal for maintaining communication quality;
Transmission control means for transmitting a third control signal for maintaining communication quality immediately after the end of the idle time,
The second control signal is transmission power control information for a reverse line, and the third control signal is a pilot signal used for demodulation of communication data or transmission power control for a forward line. A base station is obtained.
And it switches to the communication mode which provides the said idle time with a predetermined period, It switches to the communication mode which provides the said idle time by notifying to a mobile station, It is characterized by the above-mentioned. Also, the communication mode is characterized in that the communication mode is set to provide the idle time by notifying the mobile station according to the line quality state, and the idle time is provided by notifying the mobile station according to the congestion state. It is characterized by switching to the mode. Further, the communication mode is switched to a communication mode in which the idle time is provided by a notification from the mobile station.
[0036]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile station in the mobile communication system,
Quality measuring means for receiving a first control signal for maintaining communication quality transmitted in the idle time and measuring the reception quality based on the first control signal;
A mobile station characterized by including transmission means for generating and transmitting forward transmission power control information according to the reception quality is obtained.
[0037]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile station in the mobile communication system,
Means for receiving a first control signal for maintaining communication quality transmitted in the idle time;
A mobile station comprising demodulating means for demodulating communication data using the first control signal is obtained.
[0038]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile station in the mobile communication system,
Means for receiving a first control signal for maintaining communication quality transmitted in the idle time;
The mobile station is characterized by including means for controlling the transmission power in the reverse direction according to the first control signal.
[0039]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile station in the mobile communication system,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time;
Quality measuring means for measuring the reception quality based on the control signal;
A mobile station characterized by including transmission means for generating and transmitting forward transmission power control information according to the reception quality is obtained.
[0040]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile station in the mobile communication system,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time;
A mobile station comprising demodulating means for demodulating communication data using this control signal is obtained.
[0041]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile station in the mobile communication system,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time;
Means for controlling the transmission power in the reverse direction based on the second control signal is obtained.
[0042]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile station in the mobile communication system,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time, and receiving a third control signal for maintaining communication quality immediately after the idle time;
Quality measuring means for measuring the reception quality based on these second or third control signals;
A mobile station characterized by including transmission means for generating and transmitting forward transmission power control information according to the reception quality is obtained.
[0043]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile station in the mobile communication system,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time, and receiving a third control signal for maintaining communication quality immediately after the idle time;
A mobile station characterized by including demodulation means for demodulating communication data using these second or third control signals can be obtained.
[0044]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile station in the mobile communication system,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time, and receiving a third control signal for maintaining communication quality immediately after the idle time;
Quality measuring means for measuring the reception quality based on the third control signal;
Transmission means for generating and transmitting forward transmission power control information according to the reception quality,
And a means for controlling transmission power in the reverse direction based on the second control signal.
[0045]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile station in the mobile communication system,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time, and receiving a third control signal for maintaining communication quality immediately after the idle time;
Demodulating means for demodulating communication data using the third control signal;
And a means for controlling transmission power in the reverse direction based on the second control signal.
[0046]
According to the present invention, a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station, including a base station and a mobile station. A mobile station in the mobile communication system,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time, and receiving a third control signal for maintaining communication quality immediately after the idle time;
Demodulating means for demodulating communication data using the third control signal;
Quality measuring means for measuring the reception quality based on the third control signal;
Transmission means for generating and transmitting forward transmission power control information according to the reception quality,
And a means for controlling transmission power in the reverse direction based on the second control signal.
[0047]
The first control signal includes a pilot signal used for demodulation of the communication data or transmission power control for a forward link, and the second control signal includes the communication data. It includes a pilot signal used for demodulation or transmission power control for the forward link. The third control signal includes a pilot signal used for demodulation of the communication data or transmission power control for the forward link, and the first control signal is for the reverse link. It also includes transmission power control information. Further, the second control signal also includes transmission power control information for the reverse link.
[0048]
The first control signal also includes a pilot signal used for demodulation of communication data or transmission power control for a forward link, and transmission power control information for a reverse link. The second control signal also includes a pilot signal used for demodulation of communication data or transmission power control for a forward link, and transmission power control information for a reverse link. The control signal includes a pilot signal used for demodulation of communication data or transmission power control for a forward link, and transmission power control information for a reverse link. In addition, the communication mode is characterized in that the communication mode is set to provide the idle time at a predetermined cycle, and the communication mode is set to provide the idle time by a notification from the base station.
In addition, the communication mode is characterized by switching to a communication mode that provides the idle time by notifying the base station, and the communication mode is characterized by switching to the communication mode that provides the idle time by notifying the base station according to a line quality state. And
[0049]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. FIG. 1 is a block diagram of a base station according to an embodiment of the present invention. The input transmission data is input to the error correction encoding unit 1, subjected to error correction encoding, and supplied to the segmentation unit 2. In each of the slots that are generated segments, the pit signal PL, the transmission power control signal TPC, the transmission rate information RI, and the like, which are the control signals shown in (c) to (e) of FIG. Inserted. The output of the segmentation unit 2 is modulated by the modulation unit 3, supplied to the antenna 7 from the transmission / reception shared circuit 6 via the spreading circuit 4 and the power amplifier 5, and transmitted.
[0050]
A received signal from a mobile station, which will be described later, is supplied to the despreading circuit 8 via the antenna 7 and the transmission / reception shared circuit 6, demodulated by the demodulator 9, and output. The pilot signal of the control signal is extracted from the output of the demodulator 9 by the pilot signal extractor 10, and the SIR measurement unit 11 performs uplink SIR measurement. In the TPC signal generator 12, the measured SIR value is compared with the target value, and transmission power control information TPC for the uplink is generated according to the comparison result. The transmission power control information TPC is sent to the control signal inserting unit 13 and inserted into each segment together with other control information such as a pilot signal. On the other hand, transmission power control information TPC for the downlink is extracted from the output of the demodulation unit 9 by the TPC signal extraction unit 14, and gain control of the power amplifier 5 is performed according to the information TPC.
[0051]
Here, as described above, as a method for generating the idle time T4 shown in FIG. 10, there are a method by puncturing and a method for lowering the spreading factor. The former method is a method in which, for example, data for 16 slots is thinned out to data for 15 slots in the error correction encoding unit 1. As a result, an empty time for one slot is generated. In the latter method of reducing the spreading factor, in the segmenting unit 2, for example, the data for 16 slots is set to 8 segments and the spreading factor is halved to increase the transmission speed by 2 times and to signal in the time axis direction. , And a relatively long free time can be generated. Using this idle time, the mobile station performs different frequency carrier quality measurements and performs various other processes. In the present invention, the control signal insertion unit 13 transmits the control signal even in this idle time. Insert it.
[0052]
FIG. 2 is a flowchart showing an outline of the operation of the base station shown in FIG. Referring to FIG. 2, first, error correction coding of transmission data is performed (step S1), and segmentation is performed (step S2). At this time, idle time is generated at a constant period. (Step S3). The control signal is inserted into each segment in the normal data transmission period (steps S4 and S10), and the control signal is inserted also before the idle time, the idle time, or immediately after the idle time (steps S4 and S5). ). And it transmits, performing transmission power control (step S6).
[0053]
On the other hand, a control signal is extracted from the received data (step S7), and SIR measurement is performed using a pilot signal in the control signal (step S8). The measurement result and the target value are compared, and transmission power control information TPC for the uplink according to the comparison result is generated (step S9), together with other control signals such as pilot signals, each segment and the free time. (Steps S5 and S10). Further, transmission power control is performed in accordance with transmission power control information TPC for the downlink in the control signal extracted in step S7 (step S6).
[0054]
Various examples of inserting the control signal in the idle time in this case are shown in FIGS. The example of FIG. 3 is effective mainly when the idle time T4 is relatively long, and corresponds to the case where the idle time is secured by changing the spreading factor in the slotted mode. If the idle time is relatively long, the processing to be performed in the idle time, for example, in the case of different frequency carrier quality measurement is not performed as one continuous idle time. This is subdivided into small blocks T41 and T42, and the control signal 101 is transmitted during the time between these small blocks.
[0055]
FIG. 3 shows the case where the control signal transmission is performed once during the idle time T4. However, it is obvious that the control signal transmission may be performed a plurality of times. At that time, the transmission interval between the plurality of control signals inserted during the idle time T4 may be set longer than the transmission interval of the same type of control signals in the normal transmission mode.
[0056]
In the example of FIG. 4, the idle time T4 is relatively short, and is applied when it is difficult to measure different frequency carrier quality, for example, which should be executed during the subdivided time. This mainly applies to the case where an empty time is secured by puncturing in the slotted mode. In this example, before entering the idle time T4, after transmitting to the control signal 101 immediately after the information signal transmission in the different frequency carrier quality measurement mode, the idle time is entered. Since the transmission power of the uplink (reverse direction) line is implemented by the control signal 101, the characteristics of the uplink (reverse direction) line are improved as compared with the conventional case in which the idle time is entered immediately after the information signal transmission.
[0057]
In this example, as in the case of FIGS. 11C, 11D, and 11E, in the case of a slot format in which some or all of the control signals exist near the beginning of the slot where the idle time T4 starts. It is effective. In this example, the idle time T4 is short. However, even if the idle time is long, as shown in FIG. 4, after transmitting to the next control signal before entering the idle time without subdividing it, as shown in FIG. Obviously, the measurement of different frequency carrier quality may be started.
[0058]
In the example of FIG. 5, the control signal 101 is inserted immediately after the idle time T4. This example is effective in the case of a slot format in which some or all of the control signals exist at the end of the slot where the idle time T4 ends, as in the case of FIG. Of course, in this example as well, control signals may be inserted at regular time intervals. In this example, at the same time, as shown in FIG. 4, control signal transmission is performed immediately before the idle time T4, and transmission of communication data to a mobile station that receives a different frequency carrier after transmission of the control signal is stopped. Of course, it is also possible.
[0059]
FIG. 6 is a block diagram of the mobile station in the embodiment of the present invention. Referring to FIG. 6, the received signal from the antenna 21 is input to the despreading circuit 23 through the shared transmission / reception circuit 22, subjected to despreading processing, demodulated by the demodulation unit 24, and output. On the other hand, the input transmission data is segmented by the segmentation unit 25, input to the modulation unit 26, supplied to the transmission / reception shared circuit 22 via the spreading circuit 27 and the power amplifier 28, and transmitted from the antenna 21.
[0060]
In the pilot signal extraction unit 29, a pilot signal is extracted from the signal of the demodulation unit 24 and sent to the SIR measurement unit 30. The SIR measurement unit 30 measures the SIR of the downlink (forward direction) line, the TPC signal generation unit 31 compares the measured value with the target value, and the comparison result is the downlink (forward direction) transmission power control. The signal TPC is inserted into each segment by the control signal insertion unit 32 together with other control signals such as a pilot signal.
[0061]
On the other hand, the TPC signal extraction unit 33 extracts the uplink (reverse direction) transmission power control signal TPC from the signal of the demodulation unit 24, and the gain of the power amplifier 28 is controlled according to the signal TPC.
[0062]
FIG. 7 is a schematic block diagram showing the operation of the mobile station shown in FIG. Referring to FIG. 7, the transmission data is segmented (step S21), and a control signal is inserted into each segment (step S22). Then, transmission is performed while performing transmission power control (step S23).
[0063]
On the other hand, a control signal is extracted from the received data (step S24), and SIR measurement is performed using the pilot signal in the control signal (step S25). The SIR measurement value is compared with the target value, and a downlink (forward) transmission power control signal TPC is generated according to the comparison result (step S26). The generated transmission power control signal TPC is inserted into the segment in step S22. Further, transmission power control is performed according to the uplink (reverse direction) transmission control signal TPC in the extraction control signal from the received data (step S23), and uplink (reverse direction) transmission is performed.
[0064]
In the above example, the control signal for the uplink and the downlink is described as including the pilot signal PL and the transmission power control information TPC, respectively. In this case, the transmission power in both directions can be controlled. In particular, even in the idle time T4, the mobile station is configured to include the pilot signal PL and the transmission power control information TPC as the control signal 101. Therefore, it is possible to suppress the deterioration of the transmission power characteristic of the uplink in particular.
[0065]
As another example, only the pilot signal PL can be used as the control signal 101 during the idle time T4. For example, when the pilot signal PL is arranged at the head of the slot as shown in FIGS. 11C and 11D, as shown in FIG. 4, the pilot signal PL which is a control signal immediately after the information signal transmission is shown. Transmission of communication data to the mobile station that receives the different frequency carrier can be stopped.
[0066]
Further, when the pilot signal PL is arranged at the end of the slot as shown in FIG. 11 (e), as shown in FIG. 5, the pilot signal PL that is a control signal is inserted immediately after the end of the idle time, Transmission can be started from the pilot signal. In these cases, the mobile station can demodulate both the reception data immediately before the idle time and the reception data immediately after the idle time using the pilot signals before and after, so that the reception quality of the downlink is improved. .
[0067]
Also, in these cases, the pilot signal PL transmitted from the base station is received by the mobile station, SIR measurement is performed, and the measurement result is reported to the base station, so that the base station controls downlink transmission power. As a result, the downlink channel quality is improved. Then, by transmitting a pilot signal immediately before transmission stop (immediately before the start of idle time T4), the mobile station performs SIR measurement using the pilot signal, and sends one transmission power control command to the base station. Many transmissions can be performed, and the effect of downlink transmission power control is improved.
[0068]
Further, the control signal may be transmitted both immediately before and after the idle time. For example, in the case of the slot configuration of FIG. 11 (e), the control signal inserted immediately before the idle time can be set as transmission power control information TPC, and the control signal inserted immediately after the idle time can be set as pilot PL. . In this case, since the base station transmits the transmission power control information TPC and then stops transmitting communication data to the mobile station that receives the different frequency carrier, the mobile station uses it to transmit the uplink. Since power control can be performed, degradation in uplink quality can be reduced. In addition, since the base station starts transmission from the pilot PL, the mobile station can receive data using the pilot signals before and after the pilot PL when receiving data immediately after the idle time. The reception quality of the downlink is improved. Furthermore, the mobile station can perform SIR measurement using the pilot PL immediately after the idle time, and can transmit one more transmission power control command to the base station, and can reduce downlink quality degradation. Can do.
[0069]
Furthermore, as the timing of generating the idle time in the slotted mode, as shown in step S3 of the operation flow of FIG. 2, in addition to the method of generating the idle time with a constant cycle, the base station or the mobile station There is a method of monitoring the line quality state and generating idle time according to the line quality state. For example, the base station monitors the channel quality such as the frame error rate of the signal from the mobile station, and if the value exceeds the allowable value, it notifies the mobile station to measure the reception status of other frequency carriers. The base station enters a transmission mode in which free time is provided, and the mobile station receives the notification and starts a control operation corresponding to the transmission mode.
[0070]
Similarly, the mobile station monitors the channel quality and notifies the base station when the channel quality deteriorates. The base station receives the notification and enters a transmission mode for providing free time. At the same time, a control operation corresponding to the transmission mode is started. Furthermore, a method in which the base station monitors a line congestion state and generates idle time according to the congestion state can be considered. As a method of entering the transmission mode in which the base station monitors the congestion state of the line and provides free time, the base station monitors the number of mobile stations in communication with its own station, and if the value exceeds a predetermined value , A part of the mobile station in communication is notified to measure the reception state of other frequency carriers, and the base station enters a transmission mode in which free time is also provided for the mobile station that made the notification. A mobile station that enters and receives the notification can consider a method of starting a control operation corresponding to the transmission mode.
[0071]
【The invention's effect】
As described above, according to the present invention, in the communication method for generating and transmitting the idle time in the slotted mode during data transmission in order to perform various processes such as measurement of different frequency carrier quality, However, since the control signal for maintaining the communication quality is inserted, there is an effect that the line quality during communication does not deteriorate even if the idle time becomes long.
[0072]
That is, when a pilot signal is used as the control signal, it is possible to measure downlink quality using the pilot signal in the mobile station and report the measurement result to the base station even in the idle time. The base station can perform downlink transmission power control according to this report, thereby suppressing degradation of downlink quality. Further, when the mobile station performs reception using a plurality of pilot signals, it is possible to prevent deterioration in communication quality due to the fact that reception using the preceding and subsequent pilot signals cannot be performed.
[0073]
By transmitting the uplink transmission power control information in addition to the pilot signal as the control signal, the mobile station can control the uplink transmission power using this transmission power control information even when it is idle. Therefore, it is possible to prevent deterioration of uplink quality.
[Brief description of the drawings]
FIG. 1 is a block diagram of a base station in an embodiment of the present invention.
FIG. 2 is a flowchart showing an operation of the base station of FIG.
FIG. 3 is a diagram showing an example of control signal insertion in the embodiment of the present invention.
FIG. 4 is a diagram showing another example of control signal insertion in the embodiment of the present invention.
FIG. 5 is a diagram showing still another example of signal insertion in the embodiment of the present invention.
FIG. 6 is a block diagram of a mobile station in an embodiment of the present invention.
7 is a flowchart showing the operation of the mobile station of FIG.
FIG. 8 is a diagram illustrating an example of arrangement of frequency carriers.
FIG. 9 is a diagram illustrating a line between a base station and a mobile station.
FIG. 10 is a diagram showing an example of idle time in a conventional slotted mode.
FIG. 11 is a diagram illustrating a format example of a downlink transmission signal from a base station.
[Explanation of symbols]
1 Error correction coding section
2,25 Segmentation part
3,26 Modulator
4,27 Diffusion circuit
5,28 Power amplifier
6,22 Transmission / reception shared circuit
7,21 Antenna
8,23 Despreading circuit
9,26 Demodulator
10, 29 Pilot signal extraction unit
11,30 SIR measurement unit
12, 31 TPC signal generator
13, 32 Control signal insertion part
14,33 TPC signal extractor
101 Control signal
T4 free time

Claims

A mobile communication system including a base station and a mobile station, and providing a free time generated by compressing communication data in a time axis direction in a communication frame on a forward link from the base station to the mobile station. And
The base station
Means for providing the idle time in the communication frame, and transmitting the first control signal including a pilot signal used for demodulation of the communication data or transmission power control for the forward link even in the idle time And a transmission control means.

The mobile communication system according to claim 1, wherein the transmission control means inserts the pilot signal at a predetermined time interval.

The mobile communication system according to claim 2, wherein the time interval is set longer than the time interval of the first control signal during communication.

The mobile communication according to any one of claims 1 to 3, wherein the idle time is provided immediately after a second control signal including a pilot signal used for demodulation of the communication data or transmission power control for a forward link. system.

A mobile communication system including a base station and a mobile station, and providing a free time generated by compressing communication data in a time axis direction in a communication frame on a forward link from the base station to the mobile station. And
The base station
Means for inserting a second control signal including a pilot signal used for demodulation of the communication data or transmission power control for the forward link in the communication frame; and the idle time immediately after the second control signal. And a transmission control means for providing and transmitting from the mobile communication system.

The transmission control means transmits a third control signal including a pilot signal used for demodulation of the communication data or transmission power control for a forward link immediately after the idle time ends. The mobile communication system according to any one of 1 to 5.

The mobile communication system according to any one of claims 1 to 3, wherein the first control signal includes transmission power control information for a reverse link.

The mobile communication system according to claim 4, wherein the second control signal includes transmission power control information for a reverse link.

The mobile communication system according to claim 6, wherein the third control signal includes transmission power control information for a reverse link.

A mobile communication system including a base station and a mobile station, and providing a free time generated by compressing communication data in a time axis direction in a communication frame on a forward link from the base station to the mobile station. And
The base station
Means for providing the idle time immediately after a second control signal for maintaining communication quality; and transmission control means for transmitting a third control signal for maintaining communication quality immediately after the idle time ends. Including
The mobile communication system, wherein the second and third control signals are pilot signals used for demodulation of communication data or transmission power control for a forward link.

A mobile communication system including a base station and a mobile station, and providing a free time generated by compressing communication data in a time axis direction in a communication frame on a forward link from the base station to the mobile station. And
The base station
Means for providing the idle time immediately after a second control signal for maintaining communication quality; and transmission control means for transmitting a third control signal for maintaining communication quality immediately after the idle time ends. Including
The second control signal is transmission power control information for a reverse line, and the third control signal is a pilot signal used for demodulation of communication data or transmission power control for a forward line. Mobile communication system.

The mobile communication system according to claim 1, wherein the mobile communication system is switched to a communication mode in which the idle time is provided at a predetermined cycle.

The mobile communication system according to claim 1, wherein the mobile communication system is switched to a communication mode in which the idle time is provided by notifying a mobile station from a base station.

The mobile communication system according to any one of claims 1 to 11, wherein the mobile communication system is switched to a communication mode in which the idle time is provided by notifying a mobile station according to a channel quality state observed in a base station.

The mobile communication system according to any one of claims 1 to 11, wherein the mobile communication system is switched to a communication mode in which the idle time is provided by notifying a mobile station according to a congestion state observed in a base station.

The mobile communication system according to any one of claims 1 to 11, wherein the mobile communication system is switched to a communication mode in which the idle time is provided by notifying the base station from the mobile station.

The mobile communication system according to any one of claims 1 to 11, wherein the communication mode is switched to a communication mode in which the idle time is provided by notifying a base station according to a channel quality state observed in the mobile station.

Communication in a mobile communication system including a base station and a mobile station, and providing a free time generated by compressing communication data in the time axis direction in a communication frame on a forward link from the base station to the mobile station A control method,
In the base station,
The step of providing the idle time in the communication frame and the transmission by inserting a first control signal including a pilot signal used for demodulation of the communication data or transmission power control for the forward link even in the idle time And a communication control method.

19. The communication control method according to claim 18, wherein the transmitting step inserts the first control signal at a predetermined time interval.

The communication control method according to claim 19, wherein the time interval is set longer than the time interval of the first control signal during communication.

The step of providing the idle time is characterized in that the idle time is provided immediately after the second control signal including a pilot signal used for demodulation of the communication data or transmission power control for a forward link. The communication control method according to any one of claims 18 to 20.

Communication in a mobile communication system including a base station and a mobile station, and providing a free time generated by compressing communication data in the time axis direction in a communication frame on a forward link from the base station to the mobile station A control method,
In the base station,
Inserting a second control signal including a pilot signal used for demodulating the communication data or transmitting power control for a forward link into the communication frame; and setting the idle time immediately after the second control signal. A communication control method comprising the steps of:

23. The third control signal including a pilot signal used for demodulating the communication data or transmitting power control for a forward link is transmitted immediately after the idle time ends. The communication control method described.

21. The communication control method according to claim 18, wherein the first control signal also includes transmission power control information for a reverse link.

The communication control method according to any one of claims 21 to 22, wherein the second control signal includes transmission power control information for a reverse link.

The communication control method according to claim 23, wherein the third control signal also includes transmission power control information for a reverse link.

Communication in a mobile communication system including a base station and a mobile station, and providing a free time generated by compressing communication data in the time axis direction in a communication frame on a forward link from the base station to the mobile station A control method,
In the base station,
Providing the idle time immediately after a second control signal for maintaining communication quality, and transmitting a third control signal for maintaining communication quality immediately after the idle time ends,
2. The communication control method according to claim 1, wherein the second and third control signals are pilot signals used for demodulation of communication data or transmission power control for a forward link.

Communication in a mobile communication system including a base station and a mobile station, and providing a free time generated by compressing communication data in the time axis direction in a communication frame on a forward link from the base station to the mobile station A control method,
In the base station,
Providing the idle time immediately after a second control signal for maintaining communication quality, and transmitting a third control signal for maintaining communication quality immediately after the idle time ends,
The second control signal is transmission power control information for a reverse line, and the third control signal is a pilot signal used for demodulation of communication data or transmission power control for a forward line. Communication control method.

29. The communication control method according to claim 18, wherein the communication mode is switched to a communication mode in which the idle time is provided at a predetermined cycle.

29. The communication control method according to claim 18, wherein the communication mode is switched to a communication mode in which the idle time is provided by notifying a mobile station from a base station.

The communication control method according to any one of claims 18 to 28, wherein the communication mode is switched to a communication mode in which the idle time is provided by notifying a mobile station according to a channel quality state observed in a base station.

29. The communication control method according to claim 18, wherein the communication mode is switched to a communication mode in which the idle time is provided by notifying a mobile station according to a congestion state observed in a base station.

29. The communication control method according to claim 18, wherein the communication mode is switched to a communication mode in which the idle time is provided by notifying a mobile station to a base station.

29. The communication control method according to claim 18, wherein the communication mode is switched to a communication mode in which the idle time is provided by notifying a base station according to a channel quality state observed in a mobile station.

A base in a mobile communication system comprising a base station and a mobile station, and providing a free time generated by compressing communication data in a time axis direction in a communication frame on a forward link from the base station to the mobile station Station,
Means for providing the idle time in the communication frame;
And a transmission control means for inserting and transmitting a first control signal including a pilot signal used for demodulation of the communication data or transmission power control for a forward link even in this idle time. Bureau.

36. The base station according to claim 35, wherein the transmission control means inserts the first control signal at a predetermined time interval.

The base station according to claim 36, wherein the time interval is set longer than the time interval of the first control signal during communication.

The transmission control means provides the idle time immediately after a second control signal including a pilot signal used for demodulation of the communication data or transmission power control for a forward link. Any base station.

A base in a mobile communication system comprising a base station and a mobile station, and providing a free time generated by compressing communication data in a time axis direction in a communication frame on a forward link from the base station to the mobile station Station,
Means for inserting a second control signal including a pilot signal used for demodulation of the communication data or transmission power control for a forward link in the communication frame;
Transmission control means for providing and transmitting the idle time immediately after the second control signal.

The transmission control means transmits a third control signal including a pilot signal used for demodulation of the communication data or transmission power control for a forward link immediately after the idle time ends. 35. The base station according to any one of 35 to 39.

The base station according to any one of claims 35 to 37, wherein the first control signal includes transmission power control information for a reverse link.

40. The base station according to claim 38, wherein the second control signal includes transmission power control information for a reverse link.

The base station according to claim 40, wherein the third control signal includes transmission power control information for a reverse link.

A base in a mobile communication system comprising a base station and a mobile station, and providing a free time generated by compressing communication data in a time axis direction in a communication frame on a forward link from the base station to the mobile station Station,
Means for inserting a second control signal for maintaining communication quality;
Transmission control means for providing the idle time immediately after the second control signal, and transmitting a third control signal immediately after the idle time ends,
The base station, wherein the second and third control signals are pilot signals used for demodulation of the communication data or transmission power control for a forward link.

A base in a mobile communication system comprising a base station and a mobile station, and providing a free time generated by compressing communication data in a time axis direction in a communication frame on a forward link from the base station to the mobile station Station,
Means for providing the idle time immediately after the second control signal for maintaining communication quality;
Transmission control means for transmitting a third control signal for maintaining communication quality immediately after the end of the idle time,
The second control signal is transmission power control information for a reverse line, and the third control signal is a pilot signal used for demodulation of communication data or transmission power control for a forward line. Base station.

46. The base station according to claim 35, wherein the base station is switched to a communication mode in which the idle time is provided at a predetermined cycle.

The base station according to any one of claims 35 to 45, wherein the base station is switched to a communication mode in which the idle time is provided by notifying a mobile station.

46. The base station according to claim 35, wherein the base station is switched to a communication mode in which the idle time is provided by notifying a mobile station according to a channel quality state.

46. The base station according to claim 35, wherein the base station is switched to a communication mode in which the idle time is provided by notifying a mobile station according to a congestion state.

46. The base station according to claim 35, wherein the base station is switched to a communication mode in which the idle time is provided by notification from a mobile station.

A mobile communication system comprising a base station and a mobile station, wherein a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station Station,
Quality measuring means for receiving a first control signal for maintaining communication quality transmitted in the idle time and measuring the reception quality based on the first control signal;
A mobile station comprising transmission means for generating and transmitting forward transmission power control information according to the reception quality.

A mobile communication system comprising a base station and a mobile station, wherein a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station Station,
Means for receiving a first control signal for maintaining communication quality transmitted in the idle time;
And a demodulating means for demodulating communication data using the first control signal.

A mobile communication system comprising a base station and a mobile station, wherein a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station Station,
Means for receiving a first control signal for maintaining communication quality transmitted in the idle time;
Means for controlling transmission power in the reverse direction in accordance with the first control signal.

A mobile communication system comprising a base station and a mobile station, wherein a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station Station,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time;
Quality measuring means for measuring the reception quality based on the control signal;
A mobile station comprising transmission means for generating and transmitting forward transmission power control information according to the reception quality.

A mobile communication system comprising a base station and a mobile station, wherein a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station Station,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time;
And a demodulating means for demodulating communication data using the control signal.

A mobile communication system comprising a base station and a mobile station, wherein a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station Station,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time;
Means for controlling transmission power in the reverse direction based on the second control signal.

A mobile communication system comprising a base station and a mobile station, wherein a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station Station,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time, and receiving a third control signal for maintaining communication quality immediately after the idle time;
A mobile station comprising: quality measuring means for measuring reception quality based on the second or third control signal; and transmission means for generating and transmitting forward transmission power control information in accordance with the reception quality. .

A mobile communication system comprising a base station and a mobile station, wherein a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station Station,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time, and receiving a third control signal for maintaining communication quality immediately after the idle time;
And a demodulating means for demodulating communication data using the second or third control signal.

A mobile communication system comprising a base station and a mobile station, wherein a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station Station,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time, and receiving a third control signal for maintaining communication quality immediately after the idle time;
Quality measuring means for measuring the reception quality based on the third control signal;
Transmission means for generating and transmitting forward transmission power control information according to the reception quality,
Means for controlling transmission power in the reverse direction based on the second control signal.

A mobile communication system comprising a base station and a mobile station, wherein a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station Station,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time, and receiving a third control signal for maintaining communication quality immediately after the idle time;
Demodulating means for demodulating communication data using the third control signal;
Means for controlling transmission power in the reverse direction based on the second control signal.

A mobile communication system comprising a base station and a mobile station, wherein a free time generated by compressing communication data in the time axis direction is provided in a communication frame on a forward link from the base station to the mobile station Station,
Means for receiving a second control signal for maintaining communication quality provided immediately before the idle time, and receiving a third control signal for maintaining communication quality immediately after the idle time;
Demodulating means for demodulating communication data using the third control signal;
Quality measuring means for measuring the reception quality based on the third control signal;
Transmission means for generating and transmitting forward transmission power control information according to the reception quality,
Means for controlling transmission power in the reverse direction based on the second control signal.

The mobile station according to any one of claims 51 to 52, wherein the first control signal includes a pilot signal used for demodulation of the communication data or transmission power control for a forward link.

The mobile station according to any one of claims 54, 55, 57, and 58, wherein the second control signal includes a pilot signal used for demodulation of the communication data or transmission power control for a forward link. .

The mobile station according to any one of claims 57 to 61, wherein the third control signal includes a pilot signal used for demodulation of the communication data or transmission power control for a forward link.

The mobile station according to claim 53, wherein the first control signal also includes transmission power control information for a reverse link.

The mobile station according to any one of claims 56, 59, 60 and 61, wherein the second control signal also includes transmission power control information for a reverse link.

The first control signal includes a pilot signal used for demodulation of communication data or transmission power control for a forward link, and transmission power control information for a reverse link. 53. The mobile station according to any one of 53.

The second control signal includes a pilot signal used for demodulation of communication data or transmission power control for a forward link, and transmission power control information for a reverse link. 61. The mobile station according to any one of 61.

The third control signal includes a pilot signal used for demodulation of communication data or transmission power control for a forward link, and transmission power control information for a reverse link. 61. The mobile station according to any one of 61.

The mobile station according to any one of claims 51 to 69, wherein the mobile station is switched to a communication mode in which the idle time is provided at a predetermined period.

The mobile station according to any one of claims 51 to 69, wherein the mobile station is switched to a communication mode in which the idle time is provided by a notification from a base station.

The mobile station according to any one of claims 51 to 69, wherein the mobile station is switched to a communication mode in which the idle time is provided by notifying a base station.

The mobile station according to any one of claims 51 to 69, wherein the mobile station is switched to a communication mode in which the idle time is provided by notifying a base station according to a channel quality state.
Mobile station.