JP3635564B2

JP3635564B2 - Wireless signal transmission device

Info

Publication number: JP3635564B2
Application number: JP33621699A
Authority: JP
Inventors: 凝陳; 芳明垂澤; 哲夫廣田; 俊雄野島
Original assignee: NTT Docomo Inc
Current assignee: NTT Docomo Inc
Priority date: 1999-11-26
Filing date: 1999-11-26
Publication date: 2005-04-06
Anticipated expiration: 2019-11-26
Also published as: JP2001157250A

Description

【０００１】
【発明の属する技術分野】
この発明は例えば移動通信用の基地局に利用して好適な無線信号伝送装置に関し、特にアンテナに近接して設置される塔上ユニットと、室内等に設置される室内ユニットとの間に接続されるケーブルの本数及び重量を軽減し、基地局の設置工事の施工性を向上する事を目的とした発明である。
【０００２】
【従来の技術】
無線通信装置の中で、例えば移動通信用の基地局では、アンテナ及びこのアンテナに近接して配置しなければならない送信用及び受信用増幅器は鉄塔等の高所或いは建物の屋上等の高所に設置され、送信信号発生装置及び受信信号処理装置等を格納したユニットは鉄塔等の下方にある機械室或いは屋内に設置される。
図１３は従来の移動通信用の基地局の構成の一例を示す。図中１１はアンテナ、１０はこのアンテナ１１に近接して配置される送信用及び受信用増幅器、Ｕは屋内等に設置される屋内ユニットを示す。送信用及び受信用増幅器１０は共用器１２と、送信用の電力増幅器１３と、受信用の低雑音増幅器１４とによって構成される。また、屋内ユニットＵには送信信号発生装置１５と受信信号処理装置１６とが格納される。
【０００３】
アンテナ１１で受信した無線信号は共用器１２を介して受信用増幅器を構成する低雑音増幅器１４に導かれる。低雑音増幅器１４の出力信号は、受信用給電装置１８により屋内ユニットＵに送り込まれ受信信号処理装置１６に入力される。一方、送信信号発生装置１５からの送信信号は、送信用給電装置１７により送信用増幅器を構成する電力増幅器１３に伝送され、電力増幅器１３から共用器１２を介してアンテナ１１に送られる。送信用給電装置１７と受信用給電装置１８は従来より同軸ケーブルが用いられている。
【０００４】
【発明が解決しようとする課題】
図１３に示した移動通信用の基地局においては、アンテナ１１、送信用及び受信用増幅器１０及び屋内ユニットＵはそれぞれ一つの受信信号及び送信信号を扱っている。これに対し、複数のアンテナを一定の規則でアレー状に配列し、各アンテナで送受信される信号の振幅、位相を各移動局に対して最適に制御することにより通信品質の向上を図る方法がある。
【０００５】
図１４は、その方法を用いて移動通信用の基地局を構成した例を示す。この基地局ではアンテナが複数Ｎ本設けられ、これらＮ本のアンテナのそれぞれに送信用及び受信用増幅器１０−１〜１０−Ｎが接続され、これら複数の送信用及び受信用増幅器１０−１〜１０−Ｎが塔上ユニットＵ１に格納されて高所に設置される。
屋内ユニットＵ２にはＮチャンネル分の信号処理機能を備えた送信信号発生装置１５と受信信号処理装置１６とが設けられ、これら送信信号発生装置１５と塔上ユニットＵ１との間及び受信信号処理装置１６と塔上ユニットＵ１との間のそれぞれにＮ本の同軸ケーブル１７−１〜１７−Ｎ及び１８−１〜１８−Ｎで構成された送信用給電装置１７と受信用給電装置１８とが接続されて基地局が構成される。
【０００６】
各移動局からの無線信号はアンテナ１１−１〜１１−Ｎで受信され、各アンテナ１１−１〜１１−Ｎに接続された共用器１２を経由し低雑音増幅器１４で増幅される。
このＮ個の受信信号はＮ本の受信用給電装置１８−１〜１８−Ｎにより独立して受信信号処理装置１６に伝送される。
受信信号処理装置１６はこれらの受信信号を、それぞれの振幅、位相情報を利用した演算を施すことにより、個々の移動局に対応した複数の受信情報に分離する。また、個々の移動局に向けられる送信情報は、送信信号発生装置１５により各アンテナに対応したＮ個の送信信号に変換された後、それぞれが送信用給電装置１７−１〜１７−Ｎと、各アンテナ１１−１〜１１−Ｎに接続された電力増幅器１３、及び共用器１２を経由してアンテナ１１−１〜１１−Ｎにより送信される。
【０００７】
この場合、アンテナ数をＮとすれば、送信用給電装置１７及び受信用給電装置１８を構成する同軸ケーブルは合わせて２Ｎ本が必要になる。一方、無線信号の周波数は数百ＭＨｚ以上あるため、伝送損失を抑えるために太径の同軸ケーブルを使用しなければならない。数百ＭＨｚ以上の周波数帯において１本の同軸ケーブルの仕上がり外径は通常数センチ以上になる。このため、アンテナ等が設置される塔上ユニットＵ１から機械室や屋内に設置した屋内ユニットＵ２へ大量の同軸ケーブルを施設すると、同軸ケーブルの重量、占有スペースの増大により施工性が大幅に低下する。また、同軸ケーブルの伝送損失がケーブルの長さに比例するため、長距離の伝送が困難である。
【０００８】
この発明の目的は、大量の同軸ケーブルの敷設が必要な点を解決し、アレーアンテナを用いるときの基地局の施工性を向上することにある。
【０００９】
【課題を解決するための手段】
この発明の請求項１で提案する無線信号伝送装置は、送信信号発生装置及び受信信号処理装置を格納した屋内ユニットと、
塔上に設置されたＮ個（Ｎは２以上の整数）のアンテナと、
各アンテナを送信と受信に共用するために設けられたＮ個の共用器、各共用器からの受信信号を増幅するＮ個の低雑音増幅器及びＮ個の共用器に送信信号を供給するＮ個の電力増幅器とを格納した塔上ユニットと、
この塔上ユニットに格納されたＮ個の共用器に接続されたＮ個のアンテナと、塔上ユニットに格納したＮ個の低雑音増幅器の出力信号を屋内ユニットに格納した受信信号処理装置へ伝送する受信用給電装置と、
屋内ユニットに格納された送信信号発生装置から出力されるＮ系列の送信信号を塔上ユニットに格納したＮ個の電力増幅器に伝送する送信用給電装置と、
Ｎ系列の送信信号及び受信信号を互いに中心周波数が異なる周波数多重化信号に変換するための周波数参照信号を生成する周波数参照信号発生装置と、
を具備して構成される無線信号伝送装置において、
送信用給電装置は、
送信信号発生装置から出力されるＮ系列の送信信号が入力され、各送信信号を互いに中心周波数が異なる信号に変換する第１周波数変換器と、
この第１周波数変換器から出力されるＮ系列の出力信号を周波数多重化された１系列の信号に多重化する合成器と、
この合成器の出力信号を光信号に変換する電気−光変換器と、
この電気−光変換器が出力する光信号を塔上ユニットに伝送する光ファイバ線路と、
塔上ユニットに設けられ、光ファイバ線路からの光信号を電気信号に変換する光−電気変換器と、
この光−電気変換器が出力する出力信号をＮ系列の信号に分配する分配器と、この分配器のＮ系列の出力信号の中心周波数を同一の周波数の信号に周波数変換し、その周波数変換したＮ系列の各信号をＮ個の電力増幅器に出力する第２周波数変換器とによって構成し、
受信用給電装置は、
Ｎ個の低雑音増幅器の出力側に接続され、各低雑音増幅器が出力する受信信号の中心周波数を互いに異なる周波数に変換する第３周波数変換器と、
この第３周波数変換器が出力する互いに中心周波数を異にするＮ系列の出力信号を１系列の周波数多重化信号に多重化する合成器と、
この合成器の出力信号を光信号に変換する電気−光変換器と、
この電気−光変換器が出力する光信号を屋内ユニットに伝送する光ファイバ線路と、
屋内ユニットに設けられ、光ファイバ線路からの光信号を電気信号に変換する光−電気変換器と、
この光−電気変換器の出力信号をＮ系列の信号に分配する分配器と、
この分配器が出力するＮ系列の出力信号の中心周波数を同一の周波数に変換する第４周波数変換器と、
この第４周波数変換器が出力するＮ系列の信号が入力されて受信処理する受信信号処理装置とによって構成し、
上記第１、第２、第３、及び第４周波数変換器は、
それぞれがＮ個の入力端子とＮ個の出力端子を持ち、各入力端子からの入力信号に対し、その入力信号が供給される第１フィルタと、
周波数参照信号発生装置から出力される参照信号を参照し、設定された周波数で発振するＮ個の局部発振器と、
これら第１フィルタの出力信号と局部発振器の出力信号を入力し、これらを周波数混合するＮ個のミキサと、
このミキサの出力信号をろ波し、このろ波した信号を周波数変換器の出力信号として出力する第２フィルタとによって構成されるＮ個の周波数変換回路とによって構成し、
周波数参照信号発生装置は、
周波数参照信号源とされる周波数参照信号発生器と、
この周波数参照信号発生器の出力信号を２Ｎ＋１分岐に分配し、その中の２Ｎ個の分岐出力をＮ個ずつ、第１周波数変換器と、第４周波数変換器のそれぞれのＮ個の局部発振器へ周波数参照信号として出力する第１分配器と、
この第１分配器の残りの一つの分岐出力を光信号に変換する電気−光変換器と、
この電気−光変換器が出力する光信号を塔上ユニットへ伝送する光ファイバ線路と、
塔上ユニットに設けられ、この光ファイバ線路からの光信号を電気信号に変換する光−電気変換器と、
この光−電気変換器が出力する信号をろ波するフィルタと、
このフィルタからの出力信号を２Ｎ分岐に分配し、各分岐出力をＮ個ずつ第２周波数変換器と、第３周波数変換器のそれぞれのＮ個の局部発振器へ周波数参照信号として出力する第２分配器とによって構成される。
【００１０】
この発明の請求項１で提案する無線信号伝送装置は送信用給電装置と、受信用給電装置と、周波数参照信号発生装置を３本の光ファイバ線路で構成した点を請求したが、請求項２で提案する無線信号伝送装置は送信用給電装置と、受信用給電装置と、周波数参照信号発生装置を１本の光ファイバ線路で共用する構成を請求するものである。
請求項３で提案する無線信号伝送装置は送信用給電装置と参照信号発生装置を１本の光ファイバ線路によって構成し、受信用給電装置を１本の光ファイバ線路によって構成した点を請求するものである。
【００１１】
【作用】
この発明の請求項１で提案した無線信号伝送装置によれば、塔上ユニットと屋内ユニットの間を接続する送信用給電装置と、受信用給電装置及び参照信号用給電装置の全てを光ファイバ線路で構成されたから、光ファイバ線路は周知のように軽量であり、また直径も細いので施工性を向上することができる。
また、送信信号及び受信信号を周波数多重化し、１本の光ファイバ線路に多チャンネルの送信信号及び受信信号を伝送したから、光ファイバ線路の本数を少なくできる。この点で更に施工性の向上が期待できる。
【００１２】
この発明の請求項２及び３で提案する無線信号伝送装置によれば請求項１で提案する無線信号伝送装置と比較して光ファイバ線路の本数を更に少なくすることができる。従って、請求項１で提案する無線信号伝送装置と比較して更に一層施工性を向上できる利点が得られる。
【００１３】
【発明の実施の形態】
図１及び図２にこの発明の請求項１で提案する無線信号伝送装置の実施例を示す。図１は塔上ユニットＵ１の実施例を示し、図２は屋内ユニットＵ２の実施例を示す。
図２に示す送信信号発生装置１５は、Ｎ個のアンテナに対応したＮ系列の送信信号１０１を生成する。送信信号１０１の各系列は振幅及び位相がそれぞれ所要の値に設定されているが、それらの周波数帯域は同様である。図３に送信信号１０１の周波数帯域を示す。各系列の信号の中心周波数はｆ_Tで、帯域幅はＢである。この送信信号１０１は送信用給電装置１７によりアンテナ側へ伝送される。
【００１４】
送信用給電装置１７は、第１周波数変換器２０、合成器２１、電気−光変換器２２、光ファイバ線路２３、光−電気変換器２４、分配器２５、第２周波数変換器２６とによって構成される。
送信信号１０１はまず送信用給電装置１７の第１周波数変換器２０に入力される。第１周波数変換器２０は、入力されたＮ系列の信号に対し系列ごとに周波数帯域の周波数変換を行い、ｉ番目（ｉ＝１，２，・・・，Ｎ）の系列において、信号の中心周波数をｆ_Tからｆ_iに変換する。
【００１５】
図４に第１周波数変換器２０のＮ系列の出力信号の周波数帯域を示す。図４Ａ、Ｂ・・・Ｎは各系列１，２，・・・，Ｎの周波数帯域を示す。各周波数帯域の中心周波数ｆ₁，ｆ₂・・・ｆ_Nを、例えばｆ₁＜ｆ₂＜・・・＜ｆ_Nとしても一般性を失うことがない。このような周波数変換を実現するために、第１周波数変換器２０は各系列の入力信号に対し、第１フィルタ４１、局部発振器４２、ミキサ４３、及び第２フィルタ４４からなる周波数変換回路を用いて周波数変換を行う。各系列において、中心周波数がｆ_T、通過帯域幅がＢである第１フィルタ４１は入力信号の帯域外周波成分及び雑音を除去する。ミキサ４３は第１フィルタ４１の出力信号と局部発振器４２からの局部発振信号を混合する。これによってミキサ４３の出力信号に中心周波数がｆ_iにシフトされた信号成分が含まれる。中心周波数がｆ_i、通過帯域幅がＢなる第２フィルタ４４は、ｆ_iにある信号成分だけを取り出し第１周波数変換器２０の出力信号として出力する。局部発振器４２の局部発振周波数をｆ_Ll-iとすれば、これは次のように設定される。
【００１６】
ｆ_Ll-i＝｜ｆ_T±ｆ_i｜（ｉ＝１，２，・・・，Ｎ）
第１周波数変換器２０から出力されたＮ系列の信号は合成器２１により合成される。図５にこの合成信号のスペクトルの様子を示す。合成信号は周波数軸上でｆ_i（ｉ＝１，２，・・・，Ｎ）を中心周波数としたＮ個の成分を有し、周波数多重化信号とされる。この合成信号は電気−光変換器２２により光信号に変換され、光ファイバ線路２３により塔上ユニットＵ１に伝送される。
【００１７】
塔上ユニットＵ１には光−電気変換器２４が設けられ、この光−電気変換器２４により再び電気信号に変換される。
この電気信号は分配器２５により再びＮ系列に分配され、第２周波数変換器２６に入力される。このＮ系列の信号は周波数多重化されており、それらの周波数成分は図５と同様である。
第２周波数変換器２６は各系列の入力信号に対し、第１フィルタ４５、局部発振器４６、ミキサ４７、第２フィルタ４８からなる周波数変換回路を用いて周波数帯域の周波数変換を行う。各系列において、中心周波数が互いに異なるｆ_i、通過帯域幅がＢなる第１フィルタ４５は入力信号の帯域外成分及び帯域外雑音を除去する。ミキサ４７は、第１フィルタ４５の出力信号と局部発振器４６からの局部発信信号を混合する。これによってミキサ４７の出力信号にｆ_TXなる中心周波数にシフトされた信号成分が含まれる。中心周波数がｆ_TX、通過帯域幅がＢなる第２フィルタ４８はｆ_TXにある信号成分だけを取り出し第２周波数変換器２６の出力信号として出力する。局部発振器４６の局部発振周波数をｆ_L2-iとすれば、これは次のように設定される。
【００１８】
ｆ_L2-i＝｜ｆ_TX±ｆ_i｜（ｉ＝１，２，・・・Ｎ）
送信用給電装置１７のＮ系列の出力信号１０２の周波数帯域は図６に示すようになる。出力信号１０２の各系列の信号は、各系列に対応した電力増幅器１３により増幅され、共用器１２を介して各アンテナ１１−１〜１１−Ｎに送られる。
一方、各移動局からの上り電波信号はアンテナ１１−１〜１１−Ｎにより受信され、それぞれのアンテナ１１−１〜１１−Ｎに接続された共用器１２を介して低雑音増幅器１４により増幅され、Ｎ系列の受信信号１０３が得られる。
【００１９】
受信信号１０３の各系列の信号の周波数帯域は同様であり、中心周波数は互いに同一周波数であるｆ_RXで、帯域幅がＢである。受信信号１０３は受信用給電装置１８により屋内ユニットＵ２側へ伝送される。
受信用給電装置１８は、第３周波数変換器２７、合成器２８、電気−光変換器２９、光ファイバ線路３０、光−電気変換器３１，分配器３２、第４周波数変換器３３とによって構成される。
【００２０】
送信用給電装置１７と比べて動作する周波数が異なるが、信号伝送の仕組みは送信用給電装置１７と同様である。第３周波数変換器２７は中心周波数が互いに等しいｆ_RXであるＮ系列の入力信号を、各系列において互いに中心周波数が異なるｆ_i（ｉ＝１，２，・・・，Ｎ）に変換して出力する。第４周波数変換器３３は、各系列において、入力信号の各中心周波数ｆ_iにある成分を取り出し、それを互いに等しい中心周波数ｆ_Rに変換して出力する。第３周波数変換器の各系列に対応した各局部発振器の局部発信信号の周波数をｆ_L3-iとし、第４周波数変換器の各系列に対応した局部発振器の局部発信信号の周波数をｆ_L4-iとすれば、これらは次のように設定される。
【００２１】
ｆ_L3-i＝｜ｆ_RX±ｆ_i｜（ｉ＝１，２，・・・，Ｎ）
ｆ_L4-i＝｜ｆ_R±ｆ_i｜（ｉ＝１，２，・・・，Ｎ）
第４周波数変換器３３の出力信号は受信用給電装置１８の受信信号１０４となり、受信信号処理装置１６に伝送される。
ここで、図７を用いて各周波数変換器２０、２６、２７、３３における局部発振器の構成例を説明する。図７は一つの周波数変換器の中のＮ個の局部発振器４２又は４６を示す。各局部発振器は位相固定ループ（ＰＬＬ−ｐｈａｓｅ−ｌｏｃｋｅｄｌｏｏｐ）を用いた周波数シンセサイザーで構成した場合を示す。ＰＬＬは周知のように電圧制御発振器２００と、分周器２０１と、位相比較器２０２と、ループフィルタ２０３とで構成される。
【００２２】
電圧制御発振器２００の出力信号（正弦波）の一部が分周器２０１により分周される。系列ｉに対応する局部発振器において分周器の分周率をｎ_i（ｎ_iは整数であり、ｉ＝１，２，・・・，Ｎ）とする。位相比較器２０２は分周された信号と外部から入力される周波数参照信号との位相のずれを比較し、その誤差量に応じた電圧信号を出力する。この電圧信号はローパスフィルタであるループフィルタ２０３でろ波された後に電圧制御発振器２００に入力される。
【００２３】
電圧制御発振器２００は、掛けられた制御電圧の大きさによって発振周波数が変化する。その結果、最終的に分周器２０１の出力信号の位相と参照信号の位相とのずれがほとんどなくなり、位相比較器２０２の出力電圧は０ボルトになる。このとき、周波数参照信号の周波数をｆ₀とすれば、電圧制御発振器２００の出力信号の周波数はｎ_iｆ₀となる。ｎ_iを各局部発振器毎に異なる値に設定することにより、各局部発振器の発振周波数を異ならせることができる。
【００２４】
一方、周波数参照信号発生装置１９により各局部発振器への周波数参照信号が供給される。周波数参照信号発生装置１９は、周波数参照信号発生器３４、第１分配器３５、電気−光変換器３６，光ファイバ３７、光−電気変換器３８、フィルタ３９、第２分配器４０とによって構成される。
周波数参照信号発生器３４は屋内ユニットＵ１に格納され、第１周波数変換器２０又は第４周波数変換器３３の近くに設置される。この周波数参照信号発生器３４で発生した周波数参照信号が第１分配器３５により２Ｎ＋１個の出力に分配されて、その内Ｎ個ずつ第１周波数変換器２０及び第３周波数変換器３３の各局部発振器４２へ出力される。残りの一つは電気−光変換器３６により光信号に変換され、光ファイバ線路３７によりアンテナ等が設置される塔上ユニットＵ１へ伝送される。
【００２５】
伝送された光信号は光−電気変換器３８により再び電気信号に変換される。この信号はフィルタ３９により信号帯域外雑音を除去された後、第２分配器４０により２Ｎ個の出力に分配され、第２周波数変換器２６及び第３周波数変換器２７の各局部発振器へ出力される。周波数参照信号は、通常数ＭＨｚから数十ＭＨｚで、出力の局部発信信号の周波数は通常数百ＭＨｚから数ＧＨｚであり、また局部発信信号の周波数は周波数参照信号の周波数の整数倍である。
【００２６】
送信用給電装置１７の出力信号１０２及び受信用給電装置１８の受信信号１０４の各系列の相対位相関係が元の出力信号１０２及び受信信号１０３の相対位相関係に保存されなければ、アレーアンテナが機能することができない。相対位相関係のずれの発生は各周波数変換器２０，２６，２７，３３の各局部発振器の位相のばらつきに起因する。相対位相関係を保存できるようにするために、前記のように送信用給電装置１７及び受信用給電装置１８の各周波数変換器２０，２６，２７，３３の各局部発振器として位相固定ループを用いた周波数シンセサイザーを使用し、かつそれらの周波数参照信号として全て同一の周波数参照信号を参照させることにした。こうした場合の信号伝送の位相関係について、送信用給電装置１７において、送信信号１０１の任意２系列の伝送過程における位相関係を用いて次のように説明する。
【００２７】
ここで、周波数変換の影響のみが注目されるため、送信用給電装置１７の伝送過程を図８に簡略化することができる。図８において、送信用給電装置１７の系列ｉの入力信号の位相を（２πｆ_Tｔ）とし（πは円周率であり、ｔは時間である）、別の系列ｊの入力信号の位相が系列ｉに相対してθだけの位相差があり、（２πｆ_Tｔ＋θ）であるとする。
周波数参照信号発生装置１９から供給された周波数参照信号は全て一つの周波数参照信号発生器３４の信号から分配されたものであるため、全てが同様な位相（２πｆ₀ｔ＋φ）である。ここで、ｆ₀は周波数参照信号発生器２４の発振周波数であり、φはその周波数参照信号の初期位相である。
【００２８】
第１周波数変換器２０において、系列ｉの局部発振器の周波数はｆ₀のｎ₁倍で、系列ｊの局部発振器の周波数はｆ₀のｎ₂倍になっているとすると（即ち、ｆ_Ll-i＝ｎ₁ｆ₀、ｆ_L2-i＝ｎ₂ｆ₀）、それぞれの位相は（２πｎ₁ｆ₀ｔ＋ｎ₁φ）、及び（２πｎ₂ｆ₀ｔ＋ｎ₂φ）となる。
また、第２周波数変換器２６において、系列ｉの局部発振器の周波数はｆ₀のｍ₁倍で、系列ｊの局部発振器の周波数はｆ₀のｍ₂倍になっているとすると（即ち、ｆ_Ll-j＝ｍ₁ｆ₀、ｆ_L2-j＝ｍ₂ｆ₀）、それぞれの位相は（２πｍ₁ｆ₀ｔ＋ｍ₁φ）、及び（２πｍ₂ｆ₀ｔ＋ｍ₂φ）となる。従って、各ミキサの周波数混合により、送信用給電装置１７の出力における系列ｉ、系列ｊの位相はそれぞれ、
｛２π［ｆ_T−（ｎ₁＋ｍ₁）ｆ₀］ｔ−（ｎ₁＋ｍ₁）φ｝
及び
｛２π［ｆ_T−（ｎ₂＋ｍ₂）ｆ₀］ｔ−（ｎ₂＋ｍ₂）φ＋θ｝
となる。一方前述の説明で述べたように、ｆ_T−（ｎ₁＋ｍ₁）ｆ₀＝ｆ_T−（ｎ₂＋ｍ₂）ｆ₀＝ｆ_TXであるため、（ｎ₁＋ｍ₁）＝（ｎ₂＋ｍ₂）が成り立つ。その結果、この２系列の出力信号の相対位相差はやはりθとなり、これらの系列の入力における位相差が保たれることになる。以上の説明は２系列について行ったが、Ｎ系列についても同様であることが明らかである。また、受信用給電装置のＮ系列の受信信号の伝送についても同様である。
【００２９】
この無線伝送装置は、光ファイバ線路２３，３０，３７を境界として、アンテナ寄りの全ての装置が塔上ユニットＵ１に格納されて鉄塔等の塔上或いは建物の屋上との高所に設置され、送信信号発生装置或いは受信信号処理装置寄りの全ての装置が全てが屋内ユニットＵ２に格納されて鉄塔の下方にある機械室或いは屋内に設置される。
図９及び図１０にこの発明の請求項２で提案する無線信号伝送装置の実施例を示す。図１及び図２と対応する部分には同一符号を付して示す。
【００３０】
この発明の請求項２で提案する無線信号伝送装置は塔上ユニットＵ１と屋内ユニットＵ２との間を１本の光ファイバ線路２３によって接続し、この１本の光ファイバ線路２３を用いて送信信号と受信信号及び参照信号を、それぞれ周波数多重化した光信号で伝送し、信号の授受を行う構成とした点を特徴とするものである。
屋内ユニットＵ２及び塔上ユニットＵ１に設けられる電気−光変換器２２，３６及び２９は光の波長が互いに異なる第１光波長、第２光波長、第３光波長を持つ光を発光する発光素子で構成した電気−光変換器が用いられる。これと共に屋内ユニットＵ２に第１光合波及び分波器４９をまた、塔上ユニットＵ１に第２光合波及び分波器５０を設け、これら第１光合波及び分波器４９と第２光合波及び分波器５０により、電気−光変換器２２と３６から出力される光信号に変換された送信信号と参照信号を第１光波長信号と第２光波長信号として第１光合波及び分波器４９で合波して塔上ユニットＵ１に伝送し、塔上ユニットＵ１では第２光合波及び分波器５０で第１光波長成分と第２光波長成分を分波して送信信号と参照信号とを分離して取り出す。
【００３１】
一方受信信号は塔上ユニットＵ１側で電気−光変換器２９で光信号に変換され、この光信号を第２光合波及び分波器５０で第３光波長成分として光ファイバ線路２３に合波され、屋内ユニットＵ２に伝送される。
屋内ユニットＵ２では第１光合波及び分波器４９で第３光波長成分として取り出され、光−電気変換器３１で電気信号に変換し、分配器３２を介して第４周波数変換器３３に入力される。
【００３２】
つまり、第１光合波及び分波器４９及び第２光合波及び分波器５０はそれぞれ第１光波長から第３光波長を通すことができるポートＰ１〜Ｐ０を具備する。共通ポートＰ０は光ファイバ線路２３の各一端に接続される。
第１光波長ポートＰ１と、第２光波長ポートＰ２及び第３光波長ポートＰ３はそれぞれ各波長成分のみが通過できるフィルタ特性を有し、電気−光変換器２２と３６で光信号に変換された送信信号と参照信号は第１光波長ポートＰ１と第２光波長ポートＰ２に入力され光の波長多重化信号として光ファイバ線路２３を伝搬する。
【００３３】
塔上ユニットＵ１では第２光合波及び分波器５０は共通ポートＰ０に入力された光の波長多重化信号を、第１光波長ポートＰ１と第２光波長ポートＰ２に取り出し、この取り出した信号を光−電気変換器２４と３８で電気信号に変換し、送信信号は分配器２５を介して第２周波数変換器２６に供給され、参照信号はフィルタ３９を通じて第２分配器４０に供給されて、各局部発信回路の参照信号として供される。
【００３４】
受信信号は塔上ユニットＵ１側に設けた電気−光変換器２９で第３光波長成分を持つ光信号に変換され、この第３光波長信号が第２光波長及び分波器５０の第３光波長ポートＰ３を通じて光ファイバ線路２３に送り出され、屋内ユニットＵ２に伝送される。
図１１及び図１２はこの発明の請求項３で提案する無線信号伝送装置の実施例を示す。この発明の請求項３で提案する無線信号伝送装置は２本の光ファイバ線路２３と３０によって塔上ユニットＵ１と屋内ユニットＵ２との間を接続し、これら２本の光ファイバ線路２３と３０を使って送信信号と周波数参照信号及び受信信号を塔上ユニットＵ１と屋内ユニットＵ２との間で授受する構成とした点を特徴とするものである。
【００３５】
つまり、この実施例では送信用給電装置１７において、合成器２１の入力ポート及び分配器２５の出力ポートがそれぞれＮ＋１個になっている。合成器２１のＮ＋１個の入力ポートの内、Ｎ個が第１周波数変換器２０のＮ個の出力に接続され、分配器２５のＮ＋１個の出力ポートのうち、Ｎ個が第２周波数変換器２６のＮ個の入力端に接続される。
周波数参照信号発生装置１９の第１分配器３５の出力ポートの一つが送信用給電装置１７の合成器２１の残りの一つの入力ポートに接続され、また、送信用給電装置１７の分配器２５の残りの一つの出力ポートが周波数参照信号発生装置１９のフィルタ３９の入力端に接続される。
【００３６】
周波数参照信号の周波数は通常数ＭＨｚから数十ＭＨｚであり、第１周波数変換器２０のＮ系列の出力信号を数百ＭＨｚの周波数帯に設定すれば、合成器２１により、周波数参照信号と第１周波数変換器２０の出力信号を合成することが容易に行える。
従って周波数参照信号発生器３４からの周波数参照信号は、第１分配器３５で２Ｎ＋１に分配された後、送信用給電装置１７の合成器２１，電気−光変換器２２、光ファイバ線路２３、光−電気変換器２４、分配器２５を経由して周波数参照信号発生装置１９のフィルタ３９に伝送される。この信号はフィルタ３９で帯域外成分及び雑音を除去された後、第２分配器４０により分配され、第２周波数変換器２６及び第３周波数変換器２７に送られる。
【００３７】
【発明の効果】
以上説明したように、この発明の請求項１で提案した無線信号伝送装置によれば、アレーアンテナを用いた移動通信用基地局において、鉄塔等の塔上或いは建物の屋上等の高所に設置される塔上ユニットＵ１と鉄塔の下方にある機械室或いは屋内に設置される屋内ユニットＵ２との間の信号の伝送は光ファイバを利用した。この結果従来の同軸ケーブルと比べると、給電装置の軽量化、小型化ができ、施工性を改善できる効果がある。また、光信号が光ファイバの中での伝送損は例えば１３００ｎｍや１５５０ｎｍの光波長において非常に小さいため、数百メートルを超える長距離の伝送も実現できる。
【００３８】
また、請求項２の発明によれば、送信信号、受信信号、及び周波数参照信号の伝送を１本の光ファイバ線路を利用することにより、装置が更に簡素化され、経済性、施工性を更に改善できる効果がある。
さらに、請求項３の発明によれば、周波数参照信号の伝送を送信用給電装置を利用して行うことにより、周波数参照信号を経済的な方法で伝送することができる利点が得られる。
【図面の簡単な説明】
【図１】この発明の請求項１で提案する無線信号伝送装置の塔上ユニットの実施例を説明するためのブロック図。
【図２】この発明の請求項１で提案する無線信号伝送装置の屋内ユニットの実施例を説明するためのブロック図。
【図３】図２に示した送信信号発生装置から出力される送信信号の周波数帯域の一例を示すグラフ。
【図４】図２に示した第１周波数変換器２０から出力される送信信号の周波数帯域の一例を示すグラフ。
【図５】図２に示した合成器２１から出力される送信信号の周波数帯域の一例を示すグラフ。
【図６】図１及び図２に示した送信用給電装置から出力される出力信号の周波数帯域の一例を示すグラフ。
【図７】図１及び図２に示した実施例に用いた局部発振器の一例を説明するためのブロック図。
【図８】この発明による無線信号伝送装置における送信信号と受信信号の相対位相関係の保存を説明するための図。
【図９】この発明の請求項２で提案する無線信号伝送装置の塔上ユニットの実施例を説明するためのブロック図。
【図１０】この発明の請求項２で提案する無線信号伝送装置の屋内ユニットの実施例を説明するためのブロック図。
【図１１】この発明の請求項３で提案する無線信号伝送装置の塔上ユニットの実施例を示すブロック図。
【図１２】この発明の請求項３で提案する無線信号伝送装置の屋内ユニットの実施例を説明するためのブロック図。
【図１３】従来の技術を説明するためのブロック図。
【図１４】従来の技術の他の例を説明するためのブロック図。
【符号の説明】
Ｕ１塔上ユニット
Ｕ２屋内ユニット
１０−１〜１０−Ｎ増幅器
１１−１〜１１−Ｎアンテナ
１２共用器
１３電力増幅器
１４低雑音増幅器
１５送信信号発生装置
１６受信信号処理装置
１７送信用給電装置
１８受信用給電装置
１９周波数参照信号発生装置
２０第１周波数変換器
２１、２８合成器
２２、２９、３６電気−光変換器
２４、３１、３８光−電気変換器
２３、３０、３７光ファイバ線路
２５、３２分配器
４２、４６局部発振器
４３、４７ミキサ
４１、４４、４５、４８フィルタ
４９第１光合波及び分波器
５０第２光合波及び分波器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radio signal transmission apparatus suitable for use in, for example, a base station for mobile communication, and is particularly connected between a tower unit installed close to an antenna and an indoor unit installed indoors. This invention aims to reduce the number and weight of cables and improve the workability of base station installation work.
[0002]
[Prior art]
Among wireless communication devices, for example, in a base station for mobile communication, an antenna and transmitting and receiving amplifiers that must be placed close to the antenna are located at a high place such as a steel tower or a rooftop of a building. The unit that is installed and stores the transmission signal generation device, the reception signal processing device, and the like is installed in a machine room or indoors below a steel tower or the like.
FIG. 13 shows an example of the configuration of a conventional mobile communication base station. In the figure, 11 is an antenna, 10 is a transmitting and receiving amplifier arranged close to the antenna 11, and U is an indoor unit installed indoors. The transmission and reception amplifier 10 includes a duplexer 12, a transmission power amplifier 13, and a reception low noise amplifier 14. The indoor unit U stores a transmission signal generator 15 and a reception signal processor 16.
[0003]
A radio signal received by the antenna 11 is guided through a duplexer 12 to a low noise amplifier 14 constituting a reception amplifier. The output signal of the low noise amplifier 14 is sent to the indoor unit U by the receiving power supply device 18 and input to the received signal processing device 16. On the other hand, the transmission signal from the transmission signal generator 15 is transmitted to the power amplifier 13 constituting the transmission amplifier by the transmission power supply device 17, and is transmitted from the power amplifier 13 to the antenna 11 through the duplexer 12. Conventionally, coaxial cables are used for the transmission power supply device 17 and the reception power supply device 18.
[0004]
[Problems to be solved by the invention]
In the mobile communication base station shown in FIG. 13, the antenna 11, the transmission and reception amplifier 10 and the indoor unit U handle one reception signal and transmission signal, respectively. In contrast, there is a method for improving communication quality by arranging a plurality of antennas in an array according to a certain rule and optimally controlling the amplitude and phase of signals transmitted and received by each antenna for each mobile station. is there.
[0005]
FIG. 14 shows an example in which a base station for mobile communication is configured using this method. In this base station, a plurality of N antennas are provided, and transmission and reception amplifiers 10-1 to 10-N are connected to each of these N antennas, and the plurality of transmission and reception amplifiers 10-1 to 10-1 are connected. 10-N is stored in the tower unit U1 and installed at a high place.
The indoor unit U2 is provided with a transmission signal generation device 15 and a reception signal processing device 16 having a signal processing function for N channels, and between the transmission signal generation device 15 and the tower unit U1 and the reception signal processing device. The transmission power supply device 17 and the reception power supply device 18 constituted by N coaxial cables 17-1 to 17-N and 18-1 to 18-N are connected between the tower 16 and the tower unit U1, respectively. Thus, a base station is configured.
[0006]
Radio signals from the mobile stations are received by the antennas 11-1 to 11-N, and amplified by the low noise amplifier 14 via the duplexer 12 connected to the antennas 11-1 to 11-N.
The N reception signals are independently transmitted to the reception signal processing device 16 by the N reception power supply devices 18-1 to 18-N.
The received signal processing device 16 separates these received signals into a plurality of received information corresponding to individual mobile stations by performing calculations using the respective amplitude and phase information. Also, transmission information directed to each mobile station is converted into N transmission signals corresponding to the respective antennas by the transmission signal generating device 15, and then each of the transmission information is transmitted to the power feeding devices 17-1 to 17-N. The signals are transmitted from the antennas 11-1 to 11-N via the power amplifiers 13 connected to the antennas 11-1 to 11-N and the duplexer 12.
[0007]
In this case, assuming that the number of antennas is N, 2N coaxial cables are required to form the transmission power supply device 17 and the reception power supply device 18 in total. On the other hand, since the frequency of a radio signal is several hundred MHz or more, a large-diameter coaxial cable must be used to suppress transmission loss. In the frequency band of several hundred MHz or more, the finished outer diameter of one coaxial cable is usually several centimeters or more. For this reason, if a large amount of coaxial cable is installed from the tower unit U1 on which the antenna or the like is installed to the indoor unit U2 installed in the machine room or indoor, the workability is greatly reduced due to the increase in the weight and occupied space of the coaxial cable. . Further, since the transmission loss of the coaxial cable is proportional to the length of the cable, transmission over a long distance is difficult.
[0008]
An object of the present invention is to solve the point that a large amount of coaxial cable needs to be laid and to improve the workability of a base station when using an array antenna.
[0009]
[Means for Solving the Problems]
A radio signal transmission device proposed in claim 1 of the present invention includes an indoor unit storing a transmission signal generation device and a reception signal processing device,
N antennas (N is an integer of 2 or more) installed on the tower;
N duplexers provided to share each antenna for transmission and reception, N low-noise amplifiers for amplifying the received signal from each duplexer, and N for supplying transmission signals to N duplexers A tower unit storing a power amplifier of
N antennas connected to the N duplexers stored in the tower unit and the output signals of the N low noise amplifiers stored in the tower unit are transmitted to the reception signal processing device stored in the indoor unit. A receiving power supply device,
A power feeding device for transmission that transmits N-sequence transmission signals output from a transmission signal generator stored in the indoor unit to N power amplifiers stored in the tower unit;
A frequency reference signal generator for generating a frequency reference signal for converting N series transmission signals and reception signals into frequency multiplexed signals having different center frequencies;
In a radio signal transmission device comprising:
The power feeding device for transmission is
A first frequency converter that receives an N-sequence transmission signal output from the transmission signal generator and converts each transmission signal into a signal having a different center frequency;
A synthesizer that multiplexes an N-sequence output signal output from the first frequency converter into a frequency-multiplexed one-sequence signal;
An electro-optical converter for converting the output signal of the combiner into an optical signal;
An optical fiber line for transmitting an optical signal output from the electro-optical converter to the tower unit;
An optical-electrical converter that is provided in the tower unit and converts an optical signal from the optical fiber line into an electrical signal;
A distributor that distributes an output signal output from the photoelectric converter to N series signals, and a center frequency of the N series output signal of the distributor is converted to a signal having the same frequency, and the frequency conversion is performed. A second frequency converter for outputting each signal of the N series to N power amplifiers,
The power feeding device for reception is
A third frequency converter connected to the output side of the N low-noise amplifiers and converting the center frequency of the received signal output from each low-noise amplifier to a different frequency;
A synthesizer that multiplexes N series output signals output from the third frequency converter and having different center frequencies into one series of frequency multiplexed signals;
An electro-optical converter that converts the output signal of the combiner into an optical signal;
An optical fiber line for transmitting an optical signal output from the electro-optical converter to the indoor unit;
An optical-electrical converter that is provided in the indoor unit and converts an optical signal from the optical fiber line into an electrical signal;
A distributor for distributing an output signal of the photoelectric converter into N-sequence signals;
A fourth frequency converter that converts the center frequency of the N-sequence output signal output from the distributor into the same frequency;
A reception signal processing device configured to receive and process an N-sequence signal output from the fourth frequency converter;
The first, second, third and fourth frequency converters are:
A first filter each having N input terminals and N output terminals, to which an input signal is supplied to an input signal from each input terminal;
N local oscillators that oscillate at a set frequency with reference to the reference signal output from the frequency reference signal generator;
N mixers for inputting the output signal of the first filter and the output signal of the local oscillator, and frequency-mixing them,
The output signal of the mixer is filtered, and the filtered signal is configured by N frequency conversion circuits including a second filter that outputs the filtered signal as an output signal of the frequency converter,
The frequency reference signal generator is
A frequency reference signal generator to be a frequency reference signal source;
The output signal of the frequency reference signal generator is distributed to 2N + 1 branches, and N outputs of the 2N branches are divided into N local oscillators of the first frequency converter and the fourth frequency converter, respectively. A first distributor for outputting as a frequency reference signal;
An electro-optical converter for converting the remaining one branch output of the first distributor into an optical signal;
An optical fiber line for transmitting an optical signal output from the electro-optical converter to the tower unit;
An optical-electrical converter provided in the tower unit for converting an optical signal from the optical fiber line into an electrical signal;
A filter for filtering the signal output by the photoelectric converter;
The output signal from this filter is distributed to 2N branches, and each branch output is output as a frequency reference signal to each of the N local oscillators of the second frequency converter and the third frequency converter. It is composed of a container.
[0010]
The wireless signal transmission device proposed in claim 1 of the present invention claims that the transmission power supply device, the reception power supply device, and the frequency reference signal generation device are configured by three optical fiber lines. The wireless signal transmission device proposed in claim 1 is configured to share a transmission power supply device, a reception power supply device, and a frequency reference signal generator with a single optical fiber line.
The wireless signal transmission device proposed in claim 3 is that the transmission power supply device and the reference signal generation device are configured by one optical fiber line, and the reception power supply device is configured by one optical fiber line. It is.
[0011]
[Action]
According to the radio signal transmission device proposed in claim 1 of the present invention, all of the transmission power supply device, the reception power supply device, and the reference signal power supply device that connect the tower unit and the indoor unit are connected to the optical fiber line. Thus, the optical fiber line is lightweight as is well known, and the diameter is thin, so that the workability can be improved.
Further, since the transmission signal and the reception signal are frequency-multiplexed and the multi-channel transmission signal and the reception signal are transmitted to one optical fiber line, the number of optical fiber lines can be reduced. In this respect, further improvement in workability can be expected.
[0012]
According to the radio signal transmission apparatus proposed in claims 2 and 3 of the present invention, the number of optical fiber lines can be further reduced as compared with the radio signal transmission apparatus proposed in claim 1. Therefore, an advantage that the workability can be further improved as compared with the radio signal transmission apparatus proposed in claim 1 can be obtained.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show an embodiment of a radio signal transmission apparatus proposed in claim 1 of the present invention. FIG. 1 shows an embodiment of the tower unit U1, and FIG. 2 shows an embodiment of the indoor unit U2.
2 generates an N-sequence transmission signal 101 corresponding to N antennas. Each series of the transmission signal 101 is set to a required value in amplitude and phase, but their frequency bands are the same. FIG. 3 shows the frequency band of the transmission signal 101. The center frequency of each series of signals is f _T The bandwidth is B. The transmission signal 101 is transmitted to the antenna side by the transmission power supply device 17.
[0014]
The transmission power supply device 17 includes a first frequency converter 20, a combiner 21, an electrical-optical converter 22, an optical fiber line 23, an optical-electrical converter 24, a distributor 25, and a second frequency converter 26. Is done.
The transmission signal 101 is first input to the first frequency converter 20 of the transmission power supply device 17. The first frequency converter 20 performs frequency conversion of the frequency band for each input N-sequence signal, and the center of the signal in the i-th (i = 1, 2,..., N) sequence. F _T To f _i Convert to
[0015]
FIG. 4 shows the frequency band of the N-sequence output signal of the first frequency converter 20. 4A, B... N indicate the frequency bands of the respective series 1, 2,. Center frequency f of each frequency band ₁ , F ₂ ... f _N For example f ₁ <F ₂ <... <f _N Even so, generality will not be lost. In order to realize such frequency conversion, the first frequency converter 20 uses a frequency conversion circuit including a first filter 41, a local oscillator 42, a mixer 43, and a second filter 44 for each series of input signals. Frequency conversion. In each series, the center frequency is f _T The first filter 41 whose pass bandwidth is B removes the band peripheral wave component and noise of the input signal. The mixer 43 mixes the output signal of the first filter 41 and the local oscillation signal from the local oscillator 42. As a result, the center frequency of the output signal of the mixer 43 is f. _i The shifted signal component is included. Center frequency is f _i The second filter 44 having a pass bandwidth B is f _i Only the signal component in the signal is extracted and output as an output signal of the first frequency converter 20. The local oscillation frequency of the local oscillator 42 is set to f _Ll-i If this is set, then:
[0016]
f _Ll-i = | F _T ± f _i | (I = 1, 2,..., N)
The N series signals output from the first frequency converter 20 are combined by the combiner 21. FIG. 5 shows the spectrum of the synthesized signal. The synthesized signal is f on the frequency axis. _i It has N components with a center frequency of (i = 1, 2,..., N) and is a frequency multiplexed signal. This combined signal is converted into an optical signal by the electro-optical converter 22 and transmitted to the tower unit U1 through the optical fiber line 23.
[0017]
The tower unit U <b> 1 is provided with an optical-electrical converter 24, and is converted again into an electrical signal by the optical-electrical converter 24.
This electrical signal is again distributed to the N series by the distributor 25 and input to the second frequency converter 26. The N series signals are frequency multiplexed, and their frequency components are the same as in FIG.
The second frequency converter 26 performs frequency conversion of the frequency band on each series of input signals using a frequency conversion circuit including a first filter 45, a local oscillator 46, a mixer 47, and a second filter 48. In each series, f having different center frequencies _i , Passing The first filter 45 having a bandwidth B removes out-of-band components and out-of-band noise of the input signal. The mixer 47 mixes the output signal of the first filter 45 and the local transmission signal from the local oscillator 46. As a result, the output signal of the mixer 47 is changed to f. _TX The signal component shifted to the center frequency is included. Center frequency is f _TX , The second filter 48 having a pass bandwidth B is f _TX Only the signal component in the signal is extracted and output as an output signal of the second frequency converter 26. The local oscillation frequency of the local oscillator 46 is f _L2-i If this is set, then:
[0018]
f _L2-i = | F _TX ± f _i | (I = 1, 2,... N)
The frequency band of the N-sequence output signal 102 of the transmission power supply device 17 is as shown in FIG. The signal of each series of the output signal 102 is a power amplifier corresponding to each series. 13 And sent to each of the antennas 11-1 to 11 -N via the duplexer 12.
On the other hand, the upstream radio signal from each mobile station is received by the antennas 11-1 to 11-N and amplified by the low noise amplifier 14 via the duplexer 12 connected to each antenna 11-1 to 11-N. , N-sequence received signal 103 is obtained.
[0019]
The frequency bands of the signals of each series of the received signal 103 are the same, and the center frequencies are the same frequency. _RX And the bandwidth is B. The reception signal 103 is transmitted to the indoor unit U2 side by the reception power supply device 18.
The power feeding device for reception 18 includes a third frequency converter 27, a combiner 28, an electrical-optical converter 29, an optical fiber line 30, an optical-electrical converter 31, a distributor 32, and a fourth frequency converter 33. Is done.
[0020]
The operating frequency differs from that of the transmission power supply device 17, but the signal transmission mechanism is the same as that of the transmission power supply device 17. The third frequency converter 27 has the same center frequency f _RX The N series input signals are different in center frequency in each series f _i (I = 1, 2,..., N) and output. The fourth frequency converter 33 receives each center frequency f of the input signal in each series. _i And extract them at the same center frequency f _R Convert to and output. The frequency of the local oscillation signal of each local oscillator corresponding to each series of the third frequency converter is f _L3-i And the frequency of the local oscillator signal of the local oscillator corresponding to each series of the fourth frequency converter is f _L4-i Then, these are set as follows.
[0021]
f _L3-i = | F _RX ± f _i | (I = 1, 2,..., N)
f _L4-i = | F _R ± f _i | (I = 1, 2,..., N)
The output signal of the fourth frequency converter 33 becomes the reception signal 104 of the reception power supply device 18 and is transmitted to the reception signal processing device 16.
Here, a configuration example of a local oscillator in each of the frequency converters 20, 26, 27, and 33 will be described with reference to FIG. FIG. 7 shows N local oscillators 42 or 46 in one frequency converter. Each local oscillator shows a case where it is composed of a frequency synthesizer using a phase-locked loop (PLL-phase-locked loop). As is well known, the PLL includes a voltage controlled oscillator 200, a frequency divider 201, a phase comparator 202, and a loop filter 203.
[0022]
A part of the output signal (sine wave) of the voltage controlled oscillator 200 is divided by the frequency divider 201. In the local oscillator corresponding to the series i, the frequency division ratio of the frequency divider is n _i (N _i Is an integer, i = 1, 2,..., N). The phase comparator 202 compares the phase shift between the frequency-divided signal and the frequency reference signal input from the outside, and outputs a voltage signal corresponding to the error amount. This voltage signal is filtered by the loop filter 203 which is a low-pass filter and then input to the voltage controlled oscillator 200.
[0023]
The oscillation frequency of the voltage controlled oscillator 200 changes depending on the magnitude of the applied control voltage. As a result, the difference between the phase of the output signal of the frequency divider 201 and the phase of the reference signal finally disappears, and the output voltage of the phase comparator 202 becomes 0 volts. At this time, the frequency of the frequency reference signal is set to f ₀ Then, the frequency of the output signal of the voltage controlled oscillator 200 is n _i f ₀ It becomes. n _i Is set to a different value for each local oscillator, the oscillation frequency of each local oscillator can be made different.
[0024]
On the other hand, the frequency reference signal generator 19 supplies a frequency reference signal to each local oscillator. The frequency reference signal generator 19 includes a frequency reference signal generator 34, a first distributor 35, an electric-optical converter 36, an optical fiber 37, an optical-electric converter 38, a filter 39, and a second distributor 40. Is done.
The frequency reference signal generator 34 is stored in the indoor unit U <b> 1 and is installed near the first frequency converter 20 or the fourth frequency converter 33. The frequency reference signal generated by the frequency reference signal generator 34 is distributed to 2N + 1 outputs by the first distributor 35, and each of the N frequency local signals of the first frequency converter 20 and the third frequency converter 33. It is output to the oscillator 42. The remaining one is converted into an optical signal by the electro-optical converter 36 and transmitted to the tower unit U1 where an antenna or the like is installed by the optical fiber line 37.
[0025]
The transmitted optical signal is converted again into an electrical signal by the photoelectric converter 38. After the signal 39 is removed from the signal band by the filter 39, the signal is distributed to 2N outputs by the second distributor 40 and output to the local oscillators of the second frequency converter 26 and the third frequency converter 27. The The frequency reference signal is usually several MHz to several tens of MHz, the frequency of the output local transmission signal is usually several hundred MHz to several GHz, and the frequency of the local transmission signal is an integer multiple of the frequency of the frequency reference signal.
[0026]
If the relative phase relationship between the output signal 102 of the transmission power supply device 17 and the received signal 104 of the reception power supply device 18 is not stored in the relative phase relationship between the original output signal 102 and the reception signal 103, the array antenna functions. Can not do it. The occurrence of the relative phase relationship shift is caused by the variation in the phase of each local oscillator of each frequency converter 20, 26, 27, 33. In order to preserve the relative phase relationship, a phase-locked loop was used as each local oscillator of each of the frequency converters 20, 26, 27, and 33 of the transmission power supply device 17 and the reception power supply device 18 as described above. Frequency synthesizers were used, and all the same frequency reference signals were referred to as those frequency reference signals. The phase relationship of signal transmission in such a case will be described as follows using the phase relationship in the transmission process of any two sequences of the transmission signal 101 in the transmission power supply device 17.
[0027]
Here, since only the influence of the frequency conversion is noted, the transmission process of the transmission power supply device 17 can be simplified in FIG. In FIG. 8, the phase of the input signal of the series i of the transmission power supply device 17 is (2πf _T t) (π is the pi and t is time), and the phase of the input signal of another sequence j has a phase difference of θ relative to the sequence i, and (2πf _T t + θ).
Since the frequency reference signals supplied from the frequency reference signal generator 19 are all distributed from the signal of one frequency reference signal generator 34, they all have the same phase (2πf ₀ t + φ). Where f ₀ Is the oscillation frequency of the frequency reference signal generator 24, and φ is the initial phase of the frequency reference signal.
[0028]
In the first frequency converter 20, the frequency of the local oscillator of series i is f ₀ N ₁ The frequency of the local oscillator of series j is f ₀ N ₂ (Ie, f _Ll-i = N ₁ f ₀ , F _L2-i = N ₂ f ₀ ), Each phase is (2πn ₁ f ₀ t + n ₁ φ) and (2πn ₂ f ₀ t + n ₂ φ).
In the second frequency converter 26, the frequency of the local oscillator of series i is f. ₀ M ₁ The frequency of the local oscillator of series j is f ₀ M ₂ (Ie, f _Ll-j = M ₁ f ₀ , F _L2-j = M ₂ f ₀ ), Each phase is (2πm ₁ f ₀ t + m ₁ φ) and (2πm ₂ f ₀ t + m ₂ φ). Therefore, due to the frequency mixing of each mixer, the phases of the series i and the series j at the output of the transmission power supply device 17 are respectively
{2π [f _T -(N ₁ + M ₁ ) F ₀ ] T- (n ₁ + M ₁ ) Φ}
as well as
{2π [f _T -(N ₂ + M ₂ ) F ₀ ] T- (n ₂ + M ₂ ) Φ + θ}
It becomes. On the other hand, as mentioned in the above description, f _T -(N ₁ + M ₁ ) F ₀ = F _T -(N ₂ + M ₂ ) F ₀ = F _TX (N ₁ + M ₁ ) = (N ₂ + M ₂ ) Holds. As a result, the relative phase difference between the two series of output signals is still θ, and the phase difference at the input of these series is maintained. Although the above description has been given for two sequences, it is clear that the same applies to N sequences. The same applies to the transmission of the N-sequence received signal of the receiving power supply apparatus.
[0029]
In this wireless transmission device, all the devices near the antenna are stored in the tower unit U1 with the optical fiber lines 23, 30, and 37 as boundaries, and are installed at a high position on a tower such as a steel tower or the roof of a building, All the devices near the transmission signal generation device or the reception signal processing device are all stored in the indoor unit U2 and installed in a machine room or indoors below the steel tower.
9 and 10 show an embodiment of a radio signal transmission apparatus proposed in claim 2 of the present invention. Parts corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals.
[0030]
In the radio signal transmission apparatus proposed in claim 2 of the present invention, the tower unit U1 and the indoor unit U2 are connected by a single optical fiber line 23, and a transmission signal is transmitted using the single optical fiber line 23. The received signal and the reference signal are transmitted as frequency-multiplexed optical signals, and the signals are exchanged.
The electro-optical converters 22, 36, and 29 provided in the indoor unit U2 and the tower unit U1 emit light having first, second, and third light wavelengths having different light wavelengths. The electro-optical converter comprised by this is used. At the same time, the first optical multiplexer / demultiplexer 49 is provided in the indoor unit U2, and the second optical multiplexer / demultiplexer 50 is provided in the tower unit U1, and the first optical multiplexer / demultiplexer 49 and the second optical multiplexer are provided. And the optical signal output from the electro-optical converters 22 and 36 by the optical demultiplexer 50 and the reference signal as the first optical wavelength signal and the second optical wavelength signal, the first optical multiplexing and demultiplexing. In the tower unit U1, the first optical wavelength component and the second optical wavelength component are demultiplexed by the second optical multiplexing / demultiplexing unit 50 and referred to the transmission signal. Separate and extract the signal.
[0031]
On the other hand, the received signal is converted into an optical signal by the electro-optical converter 29 on the tower unit U1 side, and this optical signal is combined into the optical fiber line 23 as the third optical wavelength component by the second optical multiplexer / demultiplexer 50. And transmitted to the indoor unit U2.
In the indoor unit U2, it is extracted as a third optical wavelength component by the first optical multiplexer / demultiplexer 49, converted into an electrical signal by the optical-electrical converter 31, and input to the fourth frequency converter 33 via the distributor 32. Is done.
[0032]
That is, the first optical multiplexer / demultiplexer 49 and the second optical multiplexer / demultiplexer 50 each include ports P1 to P0 through which the third optical wavelength can pass from the first optical wavelength. The common port P0 is connected to each end of the optical fiber line 23.
Each of the first optical wavelength port P1, the second optical wavelength port P2, and the third optical wavelength port P3 has a filter characteristic that allows only each wavelength component to pass therethrough, and is converted into an optical signal by the electro-optical converters 22 and 36. The transmitted signal and the reference signal are input to the first optical wavelength port P1 and the second optical wavelength port P2, and propagate through the optical fiber line 23 as a wavelength multiplexed signal of light.
[0033]
In the tower unit U1, the second optical multiplexer / demultiplexer 50 extracts the wavelength multiplexed signal of the light input to the common port P0 to the first optical wavelength port P1 and the second optical wavelength port P2, and outputs the extracted signal. Is converted into an electric signal by the photoelectric converters 24 and 38, the transmission signal is supplied to the second frequency converter 26 through the distributor 25, and the reference signal is supplied to the second distributor 40 through the filter 39. The signal is used as a reference signal for each local transmission circuit.
[0034]
The received signal is converted into an optical signal having a third optical wavelength component by the electro-optical converter 29 provided on the tower unit U1 side, and the third optical wavelength signal is converted into the second optical wavelength and the third of the demultiplexer 50. The light is sent to the optical fiber line 23 through the optical wavelength port P3 and transmitted to the indoor unit U2.
11 and 12 show an embodiment of a radio signal transmission apparatus proposed in claim 3 of the present invention. The wireless signal transmission apparatus proposed in claim 3 of the present invention connects the tower unit U1 and the indoor unit U2 by two optical fiber lines 23 and 30, and connects these two optical fiber lines 23 and 30 to each other. It is characterized in that a transmission signal, a frequency reference signal, and a reception signal are exchanged between the tower unit U1 and the indoor unit U2.
[0035]
That is, in this embodiment, in the transmission power supply device 17, there are N + 1 input ports for the combiner 21 and N + 1 output ports for the distributor 25. Of the N + 1 input ports of the combiner 21, N are connected to the N outputs of the first frequency converter 20. Of the N + 1 output ports of the distributor 25, N are the second frequency converters. 26 N input terminals are connected.
One of the output ports of the first distributor 35 of the frequency reference signal generator 19 is connected to the remaining one input port of the combiner 21 of the transmission power supply device 17. The remaining one output port is connected to the input terminal of the filter 39 of the frequency reference signal generator 19.
[0036]
The frequency of the frequency reference signal is normally several MHz to several tens of MHz. If the N-sequence output signal of the first frequency converter 20 is set to a frequency band of several hundred MHz, the synthesizer 21 causes the frequency reference signal and the The output signal of the single frequency converter 20 can be easily synthesized.
Accordingly, the frequency reference signal from the frequency reference signal generator 34 is distributed to 2N + 1 by the first distributor 35, and then the combiner 21, the electro-optical converter 22, the optical fiber line 23, the light of the transmission power supply device 17. The signal is transmitted to the filter 39 of the frequency reference signal generator 19 via the electric converter 24 and the distributor 25. This signal is filtered out of the out-of-band component and noise by the filter 39, then distributed by the second distributor 40, and sent to the second frequency converter 26 and the third frequency converter 27.
[0037]
【The invention's effect】
As described above, according to the radio signal transmission apparatus proposed in claim 1 of the present invention, in a mobile communication base station using an array antenna, it is installed at a high place such as a tower or a rooftop of a building. An optical fiber was used for signal transmission between the tower unit U1 and the indoor unit U2 installed indoors or in the machine room below the steel tower. As a result, compared with the conventional coaxial cable, the power feeding device can be reduced in weight and size, and the workability can be improved. Further, since the transmission loss of the optical signal in the optical fiber is very small at an optical wavelength of, for example, 1300 nm or 1550 nm, transmission over a long distance exceeding several hundred meters can be realized.
[0038]
Further, according to the invention of claim 2, by using one optical fiber line for transmission of the transmission signal, the reception signal, and the frequency reference signal, the apparatus is further simplified, and the economical efficiency and workability are further improved. There is an effect that can be improved.
Furthermore, according to the invention of claim 3, by performing transmission of the frequency reference signal by using the transmission power supply device, there is an advantage that the frequency reference signal can be transmitted in an economical manner.
[Brief description of the drawings]
FIG. 1 is a block diagram for explaining an embodiment of a tower unit of a radio signal transmission apparatus proposed in claim 1 of the present invention;
FIG. 2 is a block diagram for explaining an embodiment of an indoor unit of a wireless signal transmission apparatus proposed in claim 1 of the present invention;
FIG. 3 is a graph showing an example of a frequency band of a transmission signal output from the transmission signal generator shown in FIG. 2;
4 is a graph showing an example of a frequency band of a transmission signal output from the first frequency converter 20 shown in FIG.
5 is a graph showing an example of a frequency band of a transmission signal output from the combiner 21 shown in FIG.
6 is a graph showing an example of a frequency band of an output signal output from the transmission power supply device shown in FIGS. 1 and 2. FIG.
7 is a block diagram for explaining an example of a local oscillator used in the embodiment shown in FIGS. 1 and 2. FIG.
FIG. 8 is a diagram for explaining the preservation of the relative phase relationship between the transmission signal and the reception signal in the wireless signal transmission device according to the present invention.
FIG. 9 is a block diagram for explaining an embodiment of the tower unit of the radio signal transmission apparatus proposed in claim 2 of the present invention;
FIG. 10 is a block diagram for explaining an embodiment of an indoor unit of a wireless signal transmission apparatus proposed in claim 2 of the present invention;
FIG. 11 is a block diagram showing an embodiment of a tower unit of a radio signal transmission apparatus proposed in claim 3 of the present invention;
FIG. 12 is a block diagram for explaining an embodiment of an indoor unit of a wireless signal transmission apparatus proposed in claim 3 of the present invention;
FIG. 13 is a block diagram for explaining a conventional technique.
FIG. 14 is a block diagram for explaining another example of the prior art.
[Explanation of symbols]
U1 Tower unit
U2 indoor unit
10-1 to 10-N amplifier
11-1 to 11-N antenna
12 Duplexer
13 Power amplifier
14 Low noise amplifier
15 Transmission signal generator
16 Received signal processing device
17 Power feeding device for transmission
18 Receiving power supply device
19 Frequency reference signal generator
20 First frequency converter
21, 28 Synthesizer
22, 29, 36 Electric-optical converter
24, 31, 38 Photoelectric converter
23, 30, 37 Optical fiber line
25, 32 distributor
42, 46 Local oscillator
43, 47 Mixer
41, 44, 45, 48 filters
49 First optical multiplexer / demultiplexer
50 Second optical multiplexer / demultiplexer

Claims

A transmission signal generator for outputting a signal in which each series is set in the same frequency band and in a required phase, and a received signal processing apparatus for setting a signal input in each frequency in the same frequency band and outputting it An indoor unit containing
Is installed on the tower, an antenna of each of the N sequence to transmit a signal set to the same frequency band at and required phase and each sequence is received in the same frequency band (N is an integer of 2 or more) An array antenna ,
N duplexers provided to share each antenna for transmission and reception, N low-noise amplifiers that amplify antenna reception signals from each duplexer, and supply antenna transmission signals to the N duplexers A tower unit storing N power amplifiers,
A power feeding device for reception which is stored in the tower unit and transmits output signals of N low noise amplifiers to a reception signal processing device stored in the indoor unit;
A transmission power supply device that transmits N series of transmission signals stored in the indoor unit and output from the transmission signal generator to N power amplifiers stored in the tower unit;
A frequency reference signal generator for generating a reference signal of frequency f ₀ for converting N-sequence transmission signals and reception signals into frequency multiplexed signals having different center frequencies;
A radio signal transmission apparatus you equipped with,
The transmission power supply device is
N-sequence transmission signals output from the transmission signal generator are input , and each transmission signal is a signal having a different center frequency using a local signal having a frequency n _i f ₀ (i = 1, 2,... N). A first frequency converter for converting to
A first combiner for multiplexing the 1-series of signals frequency-multiplexed output signal of the N sequences output from the first frequency converter,
A first electro-optical converter that converts an output signal of the first combiner into an optical signal;
A first optical fiber line for transmitting an optical signal output from the first electric-optical converter to the tower unit;
A first optical-electrical converter provided in the tower unit for converting an optical signal from the first optical fiber line into an electrical signal;
A first distributor that distributes an output signal output from the first photoelectric converter to an N-sequence signal, and a center frequency of the N-sequence output signal of the first distributor, where n _i + m _i is constant taking frequency conversion into a signal of the same frequency using a local signal of a frequency m _i f _0, and a second frequency converter which outputs the signals of the frequency-converted N series to said N power amplifiers,
The receiving power supply device is
A third frequency converter connected to the output side of the N low-noise amplifiers and converting the center frequency of the received signal output from each low-noise amplifier to a different frequency using a local signal of frequency m _i f ₀ When,
A second synthesizer that multiplexes N series output signals output from the third frequency converter and having different center frequencies into one series of frequency multiplexed signals;
A second electro-optical converter that converts the output signal of the second combiner into an optical signal;
A second optical fiber line for transmitting an optical signal output from the electro-optical converter to the indoor unit;
A second optical-electrical converter provided in the indoor unit for converting an optical signal from the second optical fiber line into an electrical signal;
A second distributor for distributing the output signal of the second photoelectric converter to N-sequence signals;
The center frequency of the N-sequence output signal output from the second distributor is converted to the same frequency by using the local signal having the frequency n _i f ₀ , and the N-sequence signal is output to the reception signal processing device . and a fourth frequency converter,
The first, second, third and fourth frequency converters are:
Each comprising N input terminals and N output terminals, the input signal from the input terminal, and N first filter to which the input signal is supplied,
N local oscillators that oscillate at a frequency n _i f ₀ or m _i f ₀ with reference to the reference signal of the frequency f ₀ output from the frequency reference signal generator;
N mixers for inputting the output signal of the first filter and the output local signal of the local oscillator, and frequency-mixing them,
The output signal of the mixer was filtered, the N Thus configured to frequency conversion circuitry configured the filtered signal by the N second filter for outputting as the output signal of the frequency converter,
The frequency reference signal generator is
A frequency reference signal generator as a reference signal source of frequency f ₀ ;
An output signal of frequency f ₀ from this frequency reference signal generator is distributed to 2N + 1 branches, and 2N branch outputs among them are divided into N pieces, each of the first frequency converter and the fourth frequency converter. A third distributor that outputs a frequency reference signal to N local oscillators;
A third electro-optical converter for converting the remaining one branch output of the third distributor into an optical signal;
A third optical fiber line for transmitting an optical signal output from the third electrical-optical converter to the tower unit;
A third optical-electrical converter provided in the tower unit for converting an optical signal from the third optical fiber line into an electrical signal;
A filter for filtering the signal output by the third photoelectric converter;
The output signal from the filter was partitioned between 2N branch, a fourth of outputting the branch output and N pieces by the second frequency converter, as each of the frequency reference signal to the N of the local oscillator of the third frequency converter A distributor;
A wireless signal transmission device comprising:

A transmission signal generator for outputting a signal in which each series is set in the same frequency band and in a required phase, and a received signal processing apparatus for setting a signal input in each frequency in the same frequency band and outputting it An indoor unit containing
Is installed on the tower, an antenna of each of the N sequence to transmit a signal set to the same frequency band at and required phase and each sequence is received in the same frequency band (N is an integer of 2 or more) An array antenna ,
N duplexers provided to share each antenna for transmission and reception, N low-noise amplifiers that amplify antenna reception signals from each duplexer, and supply antenna transmission signals to the N duplexers A tower unit storing N power amplifiers,
A power feeding device for reception which is stored in the tower unit and transmits output signals of N low noise amplifiers to a reception signal processing device stored in the indoor unit;
A transmission power supply device that transmits N series of transmission signals stored in the indoor unit and output from the transmission signal generator to N power amplifiers stored in the tower unit;
A frequency reference signal generator for generating a reference signal of frequency f ₀ for converting N-sequence transmission signals and reception signals into frequency multiplexed signals having different center frequencies;
A radio signal transmission apparatus you equipped with,
The transmission power supply device is
N-sequence transmission signals output from the transmission signal generator are input , and each transmission signal is a signal having a different center frequency using a local signal having a frequency n _i f ₀ (i = 1, 2,... N). A first frequency converter for converting to
A first synthesizer that synthesizes an N-sequence output signal output from the first frequency converter into a frequency-multiplexed one-sequence signal;
An optical converter, - first electrical converting an output signal of the first combiner to an optical signal of the first optical wavelength
Each of the multiplexing and demultiplexing ports corresponding to the first, second, and third optical wavelengths and one common port are provided, and the multiplexing and demultiplexing ports corresponding to the first optical wavelength are the first and second optical ports . A first optical multiplexer / demultiplexer connected to the output of the electro-optical converter;
An optical fiber line having one end connected to the common port of the first optical multiplexer / demultiplexer;
It is the same as that of the first optical multiplexing and demultiplexing device, a second optical multiplexer and demultiplexer of the common port is connected to the other end of the optical fiber line,
A first optical-electrical converter connected to a multiplexing and demultiplexing port corresponding to the first optical wavelength of the second optical multiplexing and demultiplexing unit and converting an optical signal therefrom to an electrical signal;
A first distributor for distributing the output signal of the first photoelectric converter to N-sequence signals;
The center frequency of the frequency band of the N-sequence output signal of the first distributor is converted to the same frequency using a local signal having a frequency m _i f ₀ where n _i + m _i is constant , and the frequency converted N A second frequency converter for outputting each signal of the series to the N power amplifiers,
The receiving power supply device is
Third frequency conversion connected to the output side of the N low-noise amplifiers and converting the center frequency in the frequency band of the received N-sequence received signals into different frequencies using local signals of frequency m _i f ₀ And
A second synthesizer for converting an N-sequence output signal output by the third frequency converter into a one-sequence frequency multiplexed signal;
The connecting an output signal of the second combiner converts the optical signal of the second optical wavelength, the optical signal to the second optical multiplexing and multiplexing and demultiplexing ports corresponding to the second optical wavelength demultiplexers 2 electro-optical converters;
Upper SL is connected to the multiplexing and demultiplexing port corresponding to the second optical wavelength of the first optical multiplexing and demultiplexing device, a second light to convert the light signal from the first optical multiplexing and demultiplexing unit into an electric signal -An electrical converter;
A second distributor for distributing the output signal of the second photoelectric converter to N-sequence signals;
The fourth frequency of converting the center frequency of the frequency band of the N-sequence output signal of the second distributor into the same frequency using the local signal of the frequency n _i f ₀ and outputting this to the received signal processing device With a converter,
The first, second, third and fourth frequency converters are:
Each with N input terminals and N output terminals, the input signal from the input terminal, and N first filter to which the input signal is supplied,
Referring to reference signal of a frequency f ₀ from the outside, and N local oscillator that oscillates at a frequency _n i _{f 0} or _m i _{f 0,}
N mixers for inputting the output signal of the first filter and the output local signal of the local oscillator and frequency-mixing them;
The output signal of the mixer was filtered, the N Bei example a frequency converter equipped and N second filter to output as an output signal of the frequency converter,
The frequency reference signal generator is
A frequency reference signal generator as a reference signal source of frequency f ₀ ;
The output signal of the frequency reference signal generator is distributed to 2N + 1 branches, of which 2N branch output terminals are divided into N, each of the N local oscillators of the first frequency converter and the fourth frequency converter. A third distributor for inputting to the frequency reference signal input terminal;
The remaining one branch output terminal of the third distributor is converted into an optical signal of the third optical wavelength, and this optical signal corresponds to the first optical multiplexing and the third optical wavelength of the demultiplexer. A third electrical-to-optical converter that inputs to the coupled and demultiplexed ports;
It is connected to the multiplexing and demultiplexing port corresponding to the second optical multiplexing and demultiplexing device third optical wavelength of the transmission power supply device, and converts the optical signal from the second optical multiplexing and demultiplexing device into an electrical signal. A third photoelectric converter
A filter for filtering the output signal of the third photoelectric converter,
The output signal from this filter is distributed to 2N branches, and N outputs of each branch are input to the frequency reference signal input terminals of the N local oscillators of the second frequency converter and the third frequency converter, respectively. A wireless signal transmission device comprising: 4 distributors.

A transmission signal generator for outputting a signal in which each series is set in the same frequency band and in a required phase, and a received signal processing apparatus for setting a signal input in each frequency in the same frequency band and outputting it An indoor unit containing
Is installed on the tower, an antenna of each of the N sequence to transmit a signal set to the same frequency band at and required phase and each sequence is received in the same frequency band (N is an integer of 2 or more) An array antenna ,
N duplexers provided to share each antenna for transmission and reception, N low-noise amplifiers that amplify antenna reception signals from each duplexer, and supply antenna transmission signals to the N duplexers A tower unit storing N power amplifiers,
A power feeding device for reception which is stored in the tower unit and transmits output signals of N low noise amplifiers to a reception signal processing device stored in the indoor unit;
A transmission power supply device that transmits N series of transmission signals stored in the indoor unit and output from the transmission signal generator to N power amplifiers stored in the tower unit;
A frequency reference signal generator for generating a reference signal of frequency f ₀ for converting N-sequence transmission signals and reception signals into frequency multiplexed signals having different center frequencies;
A radio signal transmission apparatus you equipped with,
The transmission power supply device is
N-sequence transmission signals output from the transmission signal generator are input , and each transmission signal is a signal having a different center frequency using a local signal having a frequency n _i f ₀ (i = 1, 2,... N). A first frequency converter for converting to
It has N + 1 input terminals, N of which are connected to the N series output terminals of the first frequency converter, and converts the signals from the N + 1 input terminals into a frequency multiplexed one series signal. A first synthesizer;
A first electro-optical converter that converts an output signal of the first combiner into an optical signal;
A first optical fiber line for transmitting the output optical signal of the first electro-optical converter to the tower unit;
A first optical-electrical converter installed in the tower unit for converting an optical signal from the first optical fiber line into an electrical signal;
A first distributor that distributes an output signal of the first photoelectric converter into N + 1 series signals;
An N-sequence signal of the output signals of the first distributor is input, and the center frequency of the frequency band of these N-sequence input signals is a local signal having a frequency m _i f ₀ where n _i + m _i is constant. Bei example a second frequency converter for converting the same frequency, and outputs a signal of the N sequence after conversion into the N power amplifiers used,
The receiving power supply device is
Third frequency conversion connected to the output side of the N low-noise amplifiers and converting the center frequency in the frequency band of the received N-sequence received signals into different frequencies using local signals of frequency m _i f ₀ And
A second synthesizer that synthesizes an N-sequence output signal of the third frequency converter into a frequency-multiplexed one-sequence signal;
A second electro-optical converter that converts the output signal of the second combiner into an optical signal;
A second optical fiber line for transmitting the output optical signal of the second electrical-optical converter to the indoor unit;
A second optical-electrical converter for converting an optical signal from the second optical fiber line into an electrical signal;
A second distributor for distributing the output signal of the second photoelectric converter to N-sequence signals;
The center frequency of the frequency band of the N-sequence output signal of the second distributor is converted to the same frequency using a local signal having a frequency n _i f ₀ , and this is output to the received signal processing device for example Bei and the frequency converter,
The first, second, third and fourth frequency converters are:
Each with N input terminals and N output terminals, the input signal from the input terminal, and N first filter to which the input signal is supplied,
A local oscillator that oscillates at a frequency n _i f ₀ or m _i f ₀ with reference to an external frequency reference signal;
N mixers for inputting the output signal of the first filter and the output signal of the local oscillator, and frequency-mixing them,
The output signal of the mixer was filtered, the N Bei give a frequency conversion circuit composed of the N second filter to output as an output of the frequency converter,
The frequency reference signal generator is
A frequency reference signal generator as a reference signal source of frequency f ₀ ;
The output signal of the frequency reference signal generator is distributed to 2N + 1 branches, and N of the 2N branch outputs are divided into N frequencies of the N local oscillators of the first frequency converter and the fourth frequency converter, respectively. A third distributor that inputs to the reference signal input terminal and inputs the remaining one branch output to the remaining input terminal of the combiner of the transmission power supply device;
A filter whose input terminal is connected to the remaining output terminal of the distributor of the transmission power supply device;
The inputs the output signal from the filter branches to 2N branch, the frequency reference signal input terminal of each of the N local oscillators of the branch outputs and N pieces by the second frequency converter third frequency converter radio signal transmission apparatus is characterized in that example Bei and 2 distributor.