JP4263440B2

JP4263440B2 - Wireless transmission device

Info

Publication number: JP4263440B2
Application number: JP2002226168A
Authority: JP
Inventors: 修三梅川; 洋英岩尾; 淳滝波; 二郎廣野
Original assignee: 株式会社フジテレビジョン
Priority date: 2002-08-02
Filing date: 2002-08-02
Publication date: 2009-05-13
Anticipated expiration: 2022-08-02
Also published as: JP2004072249A

Description

【０００１】
【発明の属する技術分野】
本発明は、移動体に搭載されており所定の実効輻射電力で無線信号を送信する少なくとも２つの送信装置と、該送信装置から送信された無線信号を受信する受信装置とを具備する無線伝送装置に関する。
【０００２】
【従来の技術】
従来、アナログＦＭ方式無線伝送回線を介して送信装置と受信装置との間で無線伝送を行う無線伝送装置が知られている。かかる無線伝送装置を用いた無線伝送は、マルチパスによって伝送品質が直接影響を受けるので、受信装置において受信される無線信号の受信信号電力を安定させるためには、見通し内伝送の範囲内で行う必要があるという問題点があった。
【０００３】
かかる問題点を解決するために、受信装置において受信される無線信号の受信信号電力を安定させつつ見通し外伝送を可能とするＯＦＤＭ（ＯｒｔｈｏｇｏｎａｌＦｒｅｑｕｅｎｃｙＤｅｖｉｓｉｏｎＭｕｌｔｉｐｌｅｘｉｎｇ：直交周波数分割多重）方式のデジタル無線伝送装置が開発された。この結果、ＯＦＤＭ方式デジタル無線伝送回線を介して送信装置と受信装置との間で行われる無線伝送の伝送可能範囲が、飛躍的に大きくなった。
【０００４】
【発明が解決しようとする課題】
一般に、通常のマラソンＴＶ中継番組等では、カメラ及び送信装置を搭載した少なくとも２台の移動中継車（移動体）が用意され、かかる移動中継車に搭乗しているカメラマンが、先頭集団や注目選手等と併走している状態で、当該移動中継車に搭載されたカメラを用いてマラソンＴＶ中継番組用の臨場感のある映像・音声素材を撮影する。
【０００５】
そして、上述のカメラによって撮影された映像・音声素材は、当該移動中継車に搭載された送信装置によって、ＯＦＤＭ方式デジタル無線伝送回線を介して、ビル屋上等の受信ポイント（中継ポイント）に設置された受信装置に伝送され、更に別の無線伝送回線や光ファイバ等の有線伝送回線（固定回線）を介して、スイッチングスタジオ（放送局）へ伝送され、スーパ処理等の加工がなされた後に放送される。
【０００６】
しかしながら、ＯＦＤＭ方式デジタル無線伝送回線に用いることが可能な周波数帯域が限られているため、それぞれの移動中継車に搭載された送信装置と受信装置との間の伝送で用いられるＯＦＤＭ方式デジタル無線伝送回線に隣接周波数のチャネルが割り当てられることがある。
【０００７】
かかる場合、マラソンのレース展開によって、隣接周波数のチャネルが割り当てられた２台の移動中継車が近接したり、受信ポイントに対して同一方向に並んだりした場合、受信ポイントに設置されている受信装置において、過大な隣接妨害波が入力されることによって、各送信装置からの受信信号電力強度比（デシベル）が、ＯＦＤＭ方式デジタル無線伝送回線の変調方式や誤り訂正方式によって定まる所定値（デシベル）以下となる場合では、伝送断が発生するという問題点がある。
【０００８】
また、ＯＤＦＭ方式の無線伝送装置を用いた伝送であっても、見通し外伝送においては、遮蔽損や反射、回折波のために受信信号電力が時々刻々激しく変動し、上述のような隣接妨害波による伝送断が予想外に発生するという問題点があった。
【０００９】
かかる伝送断対策は、特に、時間率要求の大きい放送番組中継用無線伝送回線においては、大きな問題となっていた。
【００１０】
そこで、本発明は、以上の点に鑑みてなされたもので、見通し外伝送のような伝送環境下においても、伝送断の発生確率を低減させる無線伝送装置を提供することを目的とする。
【００１１】
【課題を解決するための手段】
請求項１記載の発明は、移動体に搭載されており所定の実効輻射電力で無線信号を送信する少なくとも２つの送信装置と、該送信装置からそれぞれ送信された無線信号を受信する受信装置とを具備する無線伝送装置であって、前記送信装置が、前記受信装置において受信される前記無線信号の受信信号電力が、所要受信電力以上でかつ該所要受信電力を基準とした所定範囲に収まるように、送信する無線信号の実効輻射電力を制御する送信制御手段を具備することを要旨とする。
【００１２】
ＯＦＤＭ方式等のデジタル無線伝送装置においては、受信信号電力が変調方式や誤り訂正方式によって定まる所要受信電力以上であれば、受信品質は一定である。
【００１３】
したがって、かかる発明によれば、送信ポイント（移動体に搭載された送信装置）及び受信ポイント（受信装置）が特定されている放送番組中継用無線伝送回線において、それぞれの無線伝送回線の伝送特性を維持しながら、不要な電力の伝送を適応的に抑制して隣接チャネルへの妨害を軽減することができ、伝送断の発生確率を低減することができる。
【００１４】
請求項２記載の発明は、移動体に搭載されており所定の実効輻射電力で無線信号を送信する少なくとも２つの送信装置と、該送信装置から送信された無線信号を受信する受信装置とを具備する無線伝送装置であって、前記送信装置が、前記受信装置において受信される前記無線信号の受信信号電力が所要受信電力以上であり、かつ、前記受信装置において受信される２つの前記無線信号間の受信信号電力強度比が所定値以上となるように、送信する無線信号の実効輻射電力を制御する送信制御手段を具備することを要旨とする。
【００１５】
かかる発明によれば、マラソンのレース展開によって、隣接周波数のチャネルが割り当てられた２台の移動体（移動中継車）が近接したり、受信ポイントに対して同一方向に並んだりした場合であっても、各々の受信装置における受信信号電力強度比（デシベル）が、ＯＦＤＭ方式デジタル無線伝送回線の変調方式や誤り訂正方式によって定まる所定値（デシベル）以上となるように、送信装置において送信する無線信号の実効輻射信号電力を抑制するために、隣接チャネル間での混信を克服することができ、伝送断の発生確率を低減することができる。
【００１６】
請求項３記載の発明は、請求項１又は２に記載の発明において、前記送信装置が、該送信装置の位置情報を測定する位置情報測定手段と、前記位置情報と無線伝送実績情報とを関連付けて記憶する記憶手段とを具備し、前記送信制御手段が、前記位置情報と前記無線伝送実績情報とに基づいて、前記送信する無線信号の実効輻射電力を制御することを要旨とする。
【００１７】
かかる発明によれば、送信制御手段が、マラソンＴＶ中継番組等の大規模スポーツＴＶ中継番組において行われた事前伝送テストの結果（無線伝送実績情報）と、スポーツＴＶ中継番組の本番中に取得した移動距離やＧＰＳ等の位置情報とに基づいて、送信する無線信号の実効輻射電力を制御するため、特定の場所で再現性のある伝送断の発生確率を低減することができる。
【００１８】
請求項４記載の発明は、請求項１乃至３のいずれかに記載の発明において、前記受信装置が、前記送信装置から受信した前記無線信号に応じて、無線伝送路状況を検出する検出手段と、前記無線伝送路状況に基づいて、前記送信装置において前記送信する無線信号の実効輻射電力を制御するための制御情報を生成する制御情報生成手段とを具備し、前記送信制御手段が、前記制御情報に基づいて、前記送信する無線信号の実効輻射電力を制御することを要旨とする。
【００１９】
かかる発明によれば、見通し外伝送のように、無線伝送路のマルチパス発生状況が時々刻々変動する場合であっても、マルチパスの遅延量や強度等に応じた適切な伝送マージン量を考慮して、各送信装置の実効輻射電力を制御するための制御情報を生成するため、伝送断の発生確率を低減することができる。
【００２０】
請求項５記載の発明は、請求項１乃至４のいずれかに記載の発明において、前記送信装置が、前記無線信号を送信するアダプティブアンテナを具備し、前記送信制御装置が、前記アダプティブアンテナにおいてメインビーム方向及び利得を制御することによって、前記送信する無線信号の実効輻射電力を制御することを要旨とする。
【００２１】
請求項６記載の発明は、請求項１乃至５のいずれかに記載の発明において、前記送信装置が、前記無線信号を送信するアダプティブアンテナを具備し、前記送信制御装置が、前記アダプティブアンテナにおいてヌル方向及び利得を制御することによって、前記送信する無線信号の実効輻射電力を制御することを要旨とする。
【００２２】
請求項７記載の発明は、請求項１乃至５のいずれかに記載の発明において、前記送信装置が、前記無線信号の送信信号電力を制御するための出力減衰機を具備し、前記送信制御装置が、前記出力減衰機を制御することによって、前記送信する無線信号の実効輻射電力を制御することを容易とする。
【００２３】
なお、請求項１乃至３に係る発明は、受信装置側で生成した制御情報を送信側に伝達するデータや音声等のバックチャネル設備を装備することにより、リアルタイムで、当該送信装置により送信される無線信号の実効輻射電力を制御することを前提としている。
【００２４】
【発明の実施の形態】
（本発明の一実施形態に係る無線伝送装置の構成）
本発明の一実施形態に係る無線伝送装置の構成について図１乃至図４を参照しながら説明する。
【００２５】
図１は、本実施形態に係る無線伝送装置の全体構成図である。また、図２は、本実施形態に係る無線伝送装置を構成する各機能のブロック図を示す図である。
【００２６】
本実施形態に係る無線伝送装置は、図１及び図２に示すように、第１の移動中継車（移動体）２０_１及び第２の移動中継車（移動体）２０_２にそれぞれ搭載されている第１の送信装置３０_１及び第２の送信装置３０_２と、例えば、ビルの屋上等の受信ポイント１５に設置されている第１の受信装置５０_１及び第２の受信装置５０_２と、差分判定回路６０と、実効輻射電力制御回路６１とを具備している。
【００２７】
図１に示すように、第１の送信装置３０_１と第１の受信装置５０_１との間は、第１の無線伝送回線３_１を介して接続されており、第２の送信装置３０_２と第２の受信装置５０_２との間は、第２の無線伝送回線３_２を介して接続されている。ここで、第１の無線伝送回線３_１及び第２の無線伝送回線３_２は、例えば、ＯＦＤＭ方式のデジタル無線伝送回線によって構成されている。
【００２８】
また、第１の送信装置３０_１は、第１の受信装置５０_１に対して所定の実効輻射電力で無線信号を送信し、第１の受信装置５０_１は、固定回線１を介して受信した信号を放送局１０に送信する。また、第２の送信装置３０_２は、第２の受信装置５０_２に対して所定の実効輻射電力で無線信号を送信し、第２の受信装置５０_２は、固定回線１を介して受信した信号を放送局１０に送信する。
【００２９】
ここで、固定回線１は、第１の無線伝送回線３_１及び第２の無線伝送回線３_２とは別の無線伝送回線や光ファイバ等の有線伝送回線等によって構成される。また、第１の受信装置５０_１及び第２の受信装置５０_２は、別個独立のものであってもよいし、一体型のものであってもよい。
【００３０】
また、図２に示すように、第１の受信装置５０_１及び第２の受信装置５０_２は、差分判定回路６０と実効輻射電力制御回路６１とバックチャネル設備２とを介して、第１の送信装置３０_１及び第２の送信装置３０_２に接続されている。
【００３１】
第１の送信装置３０_１及び第２の送信装置３０_２は、それぞれ、送信制御部３１_１，３１_２と、事前データ記憶部３２_１，３２_２と、位置情報測定部３３_１，３３_２と、出力減衰機３４_１，３４_２と、アダプティブアンテナ３５_１，３５_２とを具備している。
【００３２】
送信制御部３１は、事前データ記憶部３２と位置情報測定部３３と出力減衰機３４とに接続されており、送信装置３０から無線伝送回線３を介して受信装置５０に送信する無線信号の実効輻射電力を制御する送信制御手段を構成する。
【００３３】
本実施形態において、無線信号の実効輻射電力の制御は、無線信号の出力（利得）及びメインビーム方向（ヌル方向）を制御することによって行われるものとする。
【００３４】
すなわち、送信制御部３１は、バックチャネル設備２を介して実効輻射電力制御回路６１から送信された制御情報や、事前データ記憶部３２に記憶されている事前データや、位置情報測定部３３によって測定された位置情報等に基づいて、送信する無線信号の実効輻射電力を制御する。
【００３５】
具体的には、送信制御部３１は、受信装置５０において受信される無線信号ｃｈ１，ｃｈ２の受信信号電力が、所要受信電力以上でかつ該所要受信電力を基準とした所定範囲に収まるように、送信する無線信号ｃｈ１，ｃｈ２の実効輻射電力を制御する。
【００３６】
ここで、上述の所要受信電力は、無線伝送回線３の変調方式や誤り訂正方式を考慮して、無線伝送回線３を介して安定した伝送が可能なように決定される。また、上述の所定範囲は、無線伝送回線３の変調方式や誤り訂正方式、送信装置３０の性能等を考慮して決定される。
【００３７】
また、送信制御部３１は、受信装置５０において受信される２つの無線信号ｃｈ１，ｃｈ２間の受信信号電力強度比（デシベル）が所定値（デシベル）以上となるように、送信する無線信号ｃｈ１，ｃｈ２の実効輻射電力を制御してもよい。
【００３８】
また、送信制御部３１は、受信装置５０において受信される無線信号の受信信号電力が所要受信電力以上であり、かつ、受信装置５０において受信される２つの無線信号ｃｈ１，ｃｈ２間の受信信号電力強度比（デシベル）が所定値（デシベル）以上となるように、送信する無線信号ｃｈ１，ｃｈ２の実効輻射電力を制御してもよい。
【００３９】
ここで、上述の所定値は、誤差許容範囲のマージンを含むように設定されてもよい。また、２つの無線信号ｃｈ１，ｃｈ２間の受信信号電力強度比は、２つの無線信号ｃｈ１，ｃｈ２間のＤＵ比（ＤｅｓｉｒｅＵｎｄｅｓｉｒｅＲａｔｉｏ）という形で算出されてもよい。
【００４０】
また、送信制御部３１は、アダプティブアンテナ３５において、メインビーム方向５（図３参照）及び利得を制御することによって、または、ヌル方向６（図３参照）及び利得を制御することによって、送信する無線信号ｃｈ１，ｃｈ２の実効輻射電力を制御することができる。
【００４１】
また、送信制御部３１は、出力減衰機３４からの出力（利得）を制御することによって、送信する無線信号ｃｈ１，ｃｈ２の実効輻射電力を制御することができる。
【００４２】
事前データ記憶部３２は、送信制御部３２に接続されており、送信装置３０の位置情報と無線伝送実績情報とを関連付けた事前データを記憶する記憶手段を構成する。
【００４３】
ここで、上述の事前データは、マラソンＴＶ中継番組等の大規模スポーツ中継番組の場合に行われる事前伝送テストによって得られるものであって、送信装置３０が存在する場所を特定可能な「位置情報」と、当該位置情報によって特定される場所における無線伝送実績を示す「無線伝送実績情報」を関連付けるものである。
【００４４】
例えば、事前データ記憶部３２は、「位置情報」によって特定される場所Ａにおいて、突出した建物が存在しているため見通しが悪い環境である旨を示す「無線伝送実績情報」とを関連付ける事前データを記憶する。
【００４５】
ここで、「位置情報」は、ＧＰＳ等によって測定され得る経度・緯度情報であってもよいし、所定の場所からの移動距離情報であってもよい。
【００４６】
位置情報測定部３３は、送信制御部３１に接続されており、送信装置３０の現在の位置情報を測定する位置情報測定手段を構成する。例えば、位置情報測定部３３は、ＧＰＳ等によって構成される。ここで、位置情報測定部３３によって測定される位置情報は、事前データ記憶部３２に記憶されている「位置情報」と同一のタイプのものであることが好ましい。
【００４７】
出力減衰機３４は、送信制御部３１とアダプティブアンテナ３５とに接続されており、送信制御部３１からの指示に応じて、送信装置３０から無線伝送回線３を介して受信装置５０に送信すべきデータの出力（利得）を制御するものである。
【００４８】
アダプティブアンテナ３５は、送信制御部３１と出力減衰機３４とに接続されており、送信制御部３１からの指示に応じて、メインビーム方向５又はヌル方向６（図３参照）及び利得を制御して、出力減衰機３４から送信されたデータを無線信号ｃｈ１，ｃｈ２として無線伝送回線３に送信する。
【００４９】
第１の受信装置５０_１及び第２の受信装置５０_２は、それぞれ、アンテナ５１_１，５１_２と、受信部５２_１，５２_２と、所要受信電力判定回路５３_１，５３_２と、無線伝送路状況検出回路５４_１，５４_２とを具備している。
【００５０】
受信部５２は、無線伝送回線３及びアンテナ５１を介して、送信装置３０から送信された無線信号ｃｈ１，ｃｈ２を受信するものである。
【００５１】
所要受信電力判定回路５３は、受信部５２によって受信された無線信号ｃｈ１，ｃｈ２の受信信号電力が、所要受信電力以上でかつ該所要受信電力を基準とした所定範囲に収まっているか否かについて判定するものである。また、所要受信電力判定回路５３は、この判定結果を実効輻射電力制御回路６１に通知する。
【００５２】
無線伝送路状況検出回路５４は、受信部５２によって受信された無線信号ｃｈ１，ｃｈ２の受信信号電力や遅延プロファイルや遅延広がりや遅延スプレッド等の無線伝送路状況を検出するものである。無線伝送路状況検出回路５４は、この無線伝送路状況を実効輻射電力制御回路６１に通知する。
【００５３】
受信信号電力強度比判定回路６０は、受信装置５０の受信部５２によって受信された２つの無線信号ｃｈ１，ｃｈ２間の受信信号電力強度比（デシベル）が所定値（デシベル）以上となっているか否かについて判定するものである。受信信号電力強度比判定回路６０は、この判定結果を実効輻射電力制御回路６１に通知する。
【００５４】
実効輻射電力制御回路６１は、所要受信電力判定回路５３及び／又は受信信号電力強度比判定回路６０から受信した判定結果や、無線伝送路状況検出回路５４６０から受信した無線伝送路状況に基づいて、送信装置３０において送信する無線信号の実効輻射電力を制御するための制御情報を生成する制御情報生成手段を構成する。実効輻射電力制御回路６１は、バックチャネル設備２を介して、かかる制御情報を送信装置３０に送信する。ここで、バックチャネル設備２は、実効輻射電力制御回路６１と送信装置３０との間を無線リンクを介して接続するためのものである。
【００５５】
図４（ａ）は、無線伝送回線３を介して正常伝送が行われている場合の受信装置５０における受信信号電力を示す図であり、図４（ｂ）は、伝送断が発生している場合の受信装置５０における受信信号電力を示す図である。
【００５６】
図４（ｂ）では、２つの無線信号ｃｈ１，ｃｈ２の受信信号電力強度比（デシベル）が所定値（デシベル）以下であるため、無線伝送回線３において伝送断が発生していることを示している。
【００５７】
本発明に係る無線伝送装置の構成は、本実施形態における構成に限定するものでなく、特許請求の範囲に係る無線伝送装置を実現することができる構成であれば、任意の構成を取ることができる。
【００５８】
（本実施形態に係る無線伝送装置の動作）
上記構成を有する無線伝送装置の動作について、図５を参照にして説明する。図５は、本実施形態に係る無線伝送装置において、送信装置３０において、送信する無線信号の実効輻射電力を制御する動作を示すフローチャートである。
【００５９】
図５に示すように、ステップ５００において、各送信装置３０_１，３０_２の位置情報測定部３３_１，３３_２が、所定周期で、各送信装置３０_１，３０_２の位置情報を測定している。
【００６０】
ステップ５０１において、各受信装置５０_１，５０_２の受信部５２_１，５２_２が、無線伝送回線３を介して送信装置３０から送信された無線信号ｃｈ１，ｃｈ２を受信する。
【００６１】
ステップ５０２において、各受信装置５０_１，５０_２の所要受信電力判定部５３_１，５３_２が、各受信部５２_１，５２_２によって受信された無線信号ｃｈ１，ｃｈ２の受信信号電力が、所要受信電力以上でかつ該所要受信電力を基準とした所定範囲に収まっているか否かについて判定する。
【００６２】
ステップ５０３において、各受信装置５０_１，５０_２の無線伝送路状況検出回路５４_１，５４_２が、各受信部５２_１，５２_２によって受信された無線信号ｃｈ１，ｃｈ２の受信信号電力や遅延プロファイルや遅延広がりや遅延スプレッド等の無線伝送路状況を検出する。
【００６３】
ステップ５０４において、受信信号電力強度比判定回路６０が、各受信装置５０_１，５０_２の受信部５２_１，５２_２によって受信された２つの無線信号ｃｈ１，ｃｈ２間の受信信号電力強度比（デシベル）が所定値（デシベル）以上となっているか否かについて判定する。
【００６４】
ここで、ステップ５０２乃至５０４は、並行して行われてもよいし、所定の順序で行われてもよい。
【００６５】
ステップ５０５において、実効輻射電力制御回路６１が、所要受信電力判定回路５３及び／又は受信信号電力強度比判定回路６０から受信した判定結果や、無線伝送路状況検出回路５４から受信した無線伝送路状況に基づいて、送信装置３０において送信する無線信号の実効輻射電力を制御するための制御情報を生成する。
【００６６】
ステップ５０６において、実効輻射電力制御回路６１が、バックチャネル設備２を介して、かかる制御情報を送信装置３０に送信する。
【００６７】
ステップ５０７において、各送信装置３０_１，３０_２の送信制御部３１_１，３１_２は、バックチャネル設備２を介して実効輻射電力制御回路６１から送信された制御情報や、各事前データ記憶部３２_１，３２_２に記憶されている事前データや、各位置情報測定部３３_１，３３_２によって測定された位置情報等に基づいて、送信する無線信号の実効輻射電力を制御する。
【００６８】
（本実施形態に係る無線伝送装置の作用・効果）
本実施形態に係る無線伝送装置によれば、送信ポイント（移動体２０に搭載された送信装置３０）及び受信ポイント１５（受信装置５０）が特定されている放送番組中継用無線伝送回線３において、それぞれの無線伝送回線３の伝送特性を維持しながら、不要な電力の伝送を適応的に抑制して隣接チャネルｃｈ１，ｃｈ２への妨害を軽減することができ、伝送断の発生確率を低減することができる。
【００６９】
また、本実施形態に係る無線伝送装置によれば、マラソンのレース展開によって、隣接周波数のチャネルが割り当てられた２台の移動体（移動中継車）２０が近接したり、受信ポイント１５に対して同一方向に並んだりした場合であっても、各々の受信装置５０_１，５０_２における受信信号電力強度比（デシベル）が、ＯＦＤＭ方式デジタル無線伝送回線３の変調方式や誤り訂正方式によって定まる所定値（デシベル）以上となるように、送信装置３０_１，３０_２において送信する無線信号ｃｈ１，ｃｈ２の実効輻射信号電力を抑制するために、隣接チャネルｃｈ１，ｃｈ２間での混信を克服することができ、伝送断の発生確率を低減することができる。
【００７０】
また、本実施形態に係る無線伝送装置によれば、送信制御部３１_１，３１_２が、マラソンＴＶ中継番組等の大規模スポーツＴＶ中継番組において行われた事前伝送テストの結果（無線伝送実績情報）と、スポーツＴＶ中継番組の本番中に取得した移動距離やＧＰＳ等の位置情報とに基づいて、送信する無線信号ｃｈ１，ｃｈ２の実効輻射電力を制御するため、特定の場所で再現性のある伝送断の発生確率を低減することができる。
【００７１】
また、本実施形態に係る無線伝送装置によれば、見通し外伝送のように、受信装置５０_１，５０_２における受信信号電力が、時々刻々変動する場合であっても、受信装置５０_１，５０_２に接続されている実効輻射電力制御回路６１によって生成された制御情報を、バックチャネル設備２を介して、各移動体２０_１，２０_２に搭載された送信装置３０_１，３０_２に送信することによって、リアルタイムで、当該送信装置３０_１，３０_２により送信される無線信号ｃｈ１，ｃｈ２の実効輻射電力を制御することができる。
【００７２】
【発明の効果】
本発明によれば、見通し外伝送のような伝送環境下においても、伝送断の発生確率を低減させる無線伝送装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の一実施形態に係る無線伝送装置の全体構成図である。
【図２】本発明の一実施形態に係る無線伝送装置を構成する各機能を説明するための図である。
【図３】本発明の一実施形態に係る無線伝送装置の送信装置のアダプティブアンテナの無線信号の送信方法を説明するための図である。
【図４】本発明の一実施形態に係る無線伝送装置の受信装置における受信信号電力を示す図である。
【図５】本発明の一実施形態に係る無線伝送装置の動作を示すフローチャートである。
【符号の説明】
１…固定回線
２…バックチャネル設備
３…無線伝送回線
５…メインビーム
６…ヌル方向
１０…放送局
１５…受信ポイント
２０…移動中継車
３０…送信装置
３１…送信制御部
３２…事前データ記憶部
３３…位置情報測定部
３４…出力減衰機
３５…アダプティブアンテナ
５０…受信装置
５１…アンテナ
５２…受信部
５３…所要受信電力判定回路
５４…無線伝送路状況検出回路
６０…受信信号電力強度比判定回路
６１…実効輻射電力制御回路[0001]
BACKGROUND OF THE INVENTION
The present invention is a wireless transmission device comprising at least two transmission devices that are mounted on a mobile body and transmit wireless signals with a predetermined effective radiant power, and a reception device that receives wireless signals transmitted from the transmission devices. About.
[0002]
[Prior art]
Conventionally, a wireless transmission device that performs wireless transmission between a transmission device and a reception device via an analog FM wireless transmission line is known. Since wireless transmission using such a wireless transmission device is directly affected by multipath transmission quality, it is performed within the range of line-of-sight transmission in order to stabilize the received signal power of the wireless signal received by the receiving device. There was a problem that it was necessary.
[0003]
In order to solve such a problem, an OFDM (Orthogonal Frequency Division Multiplexing) type digital radio transmission apparatus that enables non-line-of-sight transmission while stabilizing the received signal power of a radio signal received by the reception apparatus. Was developed. As a result, the transmission range of wireless transmission performed between the transmission device and the reception device via the OFDM digital wireless transmission line has been dramatically increased.
[0004]
[Problems to be solved by the invention]
Generally, in a normal marathon TV relay program, etc., at least two mobile relay vehicles (moving bodies) equipped with a camera and a transmission device are prepared, and a cameraman boarding the mobile relay vehicle is a leading group or a player of interest. In the state where the vehicle is running in parallel, etc., a realistic video / audio material for a marathon TV broadcast program is shot using a camera mounted on the mobile relay vehicle.
[0005]
The video / audio material photographed by the above-described camera is installed at a receiving point (relay point) such as a building roof via an OFDM digital wireless transmission line by a transmission device mounted on the mobile relay vehicle. Is transmitted to the receiver, and is further transmitted to a switching studio (broadcasting station) via another wireless transmission line or a wired transmission line (fixed line) such as an optical fiber, and is broadcast after being processed such as super processing. The
[0006]
However, since the frequency band that can be used for the OFDM digital wireless transmission line is limited, the OFDM digital wireless transmission used for transmission between the transmission device and the reception device mounted on each mobile relay vehicle. An adjacent frequency channel may be assigned to the line.
[0007]
In such a case, when two mobile relay vehicles to which adjacent frequency channels are allocated are brought close to each other or lined up in the same direction with respect to the receiving point due to the marathon race development, the receiving device installed at the receiving point In FIG. 2, the reception signal power intensity ratio (decibel) from each transmitter is less than a predetermined value (decibel) determined by the modulation method and error correction method of the OFDM digital radio transmission line when an excessive adjacent interference wave is input. In such a case, there is a problem that transmission interruption occurs.
[0008]
Even in transmission using an ODFM wireless transmission device, in non-line-of-sight transmission, the received signal power fluctuates from time to time due to shielding loss, reflection, and diffracted waves, and the adjacent interference wave as described above. There was a problem that the transmission interruption due to unexpectedly occurred.
[0009]
Such countermeasures against transmission interruption have been a serious problem, particularly in broadcast program relay wireless transmission lines with high time rate requirements.
[0010]
Therefore, the present invention has been made in view of the above points, and an object of the present invention is to provide a wireless transmission device that reduces the probability of transmission interruption even in a transmission environment such as non-line-of-sight transmission.
[0011]
[Means for Solving the Problems]
The invention described in claim 1 is provided with at least two transmitting devices that are mounted on a mobile body and transmit radio signals with a predetermined effective radiation power, and receiving devices that receive radio signals respectively transmitted from the transmitting devices. A wireless transmission device comprising: the transmission device so that the reception signal power of the wireless signal received by the reception device is greater than or equal to a required reception power and falls within a predetermined range based on the required reception power. The gist of the invention is that it comprises transmission control means for controlling the effective radiation power of the radio signal to be transmitted.
[0012]
In a digital wireless transmission apparatus such as an OFDM system, the reception quality is constant if the received signal power is equal to or higher than the required reception power determined by the modulation system or error correction system.
[0013]
Therefore, according to this invention, in the radio transmission line for broadcast program relay in which the transmission point (transmission apparatus mounted on the mobile body) and the reception point (reception apparatus) are specified, the transmission characteristics of the respective radio transmission lines are set. While maintaining, it is possible to adaptively suppress transmission of unnecessary power to reduce interference with adjacent channels, and to reduce the probability of transmission interruption.
[0014]
The invention described in claim 2 includes at least two transmission devices that are mounted on a mobile body and transmit a radio signal with a predetermined effective radiation power, and a reception device that receives a radio signal transmitted from the transmission device. A wireless transmission device, wherein the transmission device has a reception signal power of the wireless signal received by the reception device that is equal to or higher than a required reception power, and between the two wireless signals received by the reception device. The gist of the present invention is to provide a transmission control means for controlling the effective radiant power of the radio signal to be transmitted so that the received signal power intensity ratio becomes equal to or greater than a predetermined value.
[0015]
According to this invention, due to the race development of the marathon, two mobile units (mobile relay vehicles) to which adjacent frequency channels are assigned are close to each other or arranged in the same direction with respect to the receiving point. In addition, the radio signal transmitted by the transmission apparatus is set so that the received signal power intensity ratio (decibel) in each reception apparatus is equal to or greater than a predetermined value (decibel) determined by the modulation scheme or error correction scheme of the OFDM digital radio transmission line. Therefore, the interference between adjacent channels can be overcome, and the probability of transmission interruption can be reduced.
[0016]
According to a third aspect of the present invention, in the first or second aspect of the present invention, the transmission device associates the position information measuring means for measuring the position information of the transmission device, and the position information and the wireless transmission performance information. And storing means for storing, wherein the transmission control means controls the effective radiant power of the radio signal to be transmitted based on the position information and the radio transmission result information.
[0017]
According to this invention, the transmission control means acquires the result of the preliminary transmission test (wireless transmission performance information) performed in the large-scale sports TV relay program such as the marathon TV relay program and the actual performance of the sports TV relay program. Since the effective radiant power of the radio signal to be transmitted is controlled based on the movement distance and position information such as GPS, the probability of occurrence of a transmission interruption with reproducibility at a specific location can be reduced.
[0018]
According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the receiving device detects a wireless transmission path condition according to the wireless signal received from the transmitting device; Control information generating means for generating control information for controlling effective radiant power of the radio signal to be transmitted in the transmitting device based on the radio transmission path condition, and the transmission control means includes the control The gist is to control the effective radiation power of the radio signal to be transmitted based on the information.
[0019]
According to this invention, even when the multipath occurrence state of the wireless transmission path varies from moment to moment as in the case of non-line-of-sight transmission, an appropriate transmission margin amount according to the delay amount or strength of the multipath is taken into consideration. And since the control information for controlling the effective radiation power of each transmission apparatus is produced | generated, the generation | occurrence | production probability of a transmission interruption can be reduced.
[0020]
According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the transmission device includes an adaptive antenna that transmits the radio signal, and the transmission control device is the main antenna in the adaptive antenna. The gist is to control the effective radiation power of the radio signal to be transmitted by controlling the beam direction and gain.
[0021]
The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the transmission device includes an adaptive antenna that transmits the radio signal, and the transmission control device is null in the adaptive antenna. The gist is to control the effective radiation power of the radio signal to be transmitted by controlling the direction and gain.
[0022]
A seventh aspect of the present invention is the transmission control apparatus according to any one of the first to fifth aspects, wherein the transmission apparatus includes an output attenuator for controlling transmission signal power of the radio signal. However, by controlling the output attenuator, it is easy to control the effective radiation power of the radio signal to be transmitted.
[0023]
The invention according to claims 1 to 3 is transmitted by the transmission device in real time by providing back channel equipment such as data and voice for transmitting the control information generated on the reception device side to the transmission side. It is assumed that the effective radiation power of the radio signal is controlled.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
(Configuration of Radio Transmission Device According to One Embodiment of the Present Invention)
A configuration of a wireless transmission apparatus according to an embodiment of the present invention will be described with reference to FIGS.
[0025]
FIG. 1 is an overall configuration diagram of a wireless transmission device according to the present embodiment. FIG. 2 is a diagram illustrating a block diagram of each function constituting the wireless transmission device according to the present embodiment.
[0026]
Radio transmission apparatus according to the present embodiment, as shown in FIGS. 1 and 2, the first mobile relay vehicle (moving object) 20 ₁ and the second mobile relay vehicle (moving object) 20 ₂ are mounted respectively a first transmission device 30 ₁ and the second transmission device 30 ₂ are, for example, the first receiver device 50 ₁ and the second receiving apparatus 50 ₂ which is installed in the receiving point 15 of the roof or the like of a building, A difference determination circuit 60 and an effective radiant power control circuit 61 are provided.
[0027]
As shown in FIG. 1, the first transmission device 30 ₁ and between the first receiver device 50 ₁ is connected through a first radio transmission link 3 _1, the second transmission device 30 ₂ When the second between the receiving device 50 ₂ is connected to the second via a radio transmission link 3 _2. Here, the first radio transmission link 3 ₁ and a second radio transmission link 3 _2, for example, is constituted by a digital radio transmission link of the OFDM scheme.
[0028]
The first transmission device 30 _1, to the first receiver device 50 ₁ transmits a radio signal at a predetermined effective radiated power, the first receiver device 50 ₁ is received via the fixed line 1 The signal is transmitted to the broadcasting station 10. The second transmission device 30 _2, to the second receiving apparatus 50 ₂ transmits a radio signal at a predetermined effective radiated power, the second receiver device 50 _2, receives through the fixed line 1 The signal is transmitted to the broadcasting station 10.
[0029]
Here, fixed line 1 is constituted by a wired transmission line or the like, such as another radio transmission link or an optical fiber from the first radio transmission link 3 ₁ and a second radio transmission link 3 _2. The first receiver device 50 ₁ and the second receiving apparatus 50 ₂ may be of independently, it may be of an integral type.
[0030]
Further, as shown in FIG. 2, the first receiver device 50 ₁ and the second receiving device 50 ₂ via the difference judgment circuit 60 and the effective radiated power control circuit 61 and the back channel equipment 2, the first It is connected to the transmission device 30 ₁ and the second transmission device 30 _2.
[0031]
The first transmission device 30 ₁ and the second transmission device 30 _2, respectively, a transmission control section ₃₁ 1, 31 _2, a pre-data storage unit ₃₂ 1, 32 _2, a position information measuring unit ₃₃ 1, 33 ₂ Output attenuators 34 ₁ , 34 ₂ and adaptive antennas 35 ₁ , 35 ₂ .
[0032]
The transmission control unit 31 is connected to the prior data storage unit 32, the position information measurement unit 33, and the output attenuator 34. The transmission control unit 31 performs effective radio signal transmission from the transmission device 30 to the reception device 50 via the wireless transmission line 3. A transmission control means for controlling the radiation power is configured.
[0033]
In the present embodiment, the effective radiant power of the radio signal is controlled by controlling the output (gain) and main beam direction (null direction) of the radio signal.
[0034]
That is, the transmission control unit 31 is measured by the control information transmitted from the effective radiation power control circuit 61 via the back channel facility 2, the prior data stored in the prior data storage unit 32, or the position information measurement unit 33. The effective radiant power of the radio signal to be transmitted is controlled based on the positional information and the like.
[0035]
Specifically, the transmission control unit 31 is configured so that the reception signal power of the radio signals ch1 and ch2 received by the reception device 50 is equal to or greater than the required reception power and falls within a predetermined range based on the required reception power. The effective radiation power of the radio signals ch1 and ch2 to be transmitted is controlled.
[0036]
Here, the required reception power described above is determined so that stable transmission is possible via the wireless transmission line 3 in consideration of the modulation method and error correction method of the wireless transmission line 3. The predetermined range is determined in consideration of the modulation scheme and error correction scheme of the wireless transmission line 3, the performance of the transmission device 30, and the like.
[0037]
Further, the transmission control unit 31 transmits the radio signals ch1 and ch1 so that the received signal power intensity ratio (decibel) between the two radio signals ch1 and ch2 received by the receiving device 50 is equal to or greater than a predetermined value (decibel). The effective radiant power of ch2 may be controlled.
[0038]
Further, the transmission control unit 31 has a received signal power of a radio signal received by the receiving device 50 that is equal to or higher than a required received power, and a received signal power between the two radio signals ch1 and ch2 received by the receiving device 50. The effective radiation power of the radio signals ch1 and ch2 to be transmitted may be controlled so that the intensity ratio (decibel) is equal to or greater than a predetermined value (decibel).
[0039]
Here, the above-described predetermined value may be set so as to include a margin of an allowable error range. Further, the received signal power intensity ratio between the two radio signals ch1 and ch2 may be calculated in the form of a DU ratio (Desire Undesire Ratio) between the two radio signals ch1 and ch2.
[0040]
Further, the transmission control unit 31 transmits the adaptive antenna 35 by controlling the main beam direction 5 (see FIG. 3) and the gain, or controlling the null direction 6 (see FIG. 3) and the gain. The effective radiant power of the radio signals ch1 and ch2 can be controlled.
[0041]
Further, the transmission control unit 31 can control the effective radiation power of the radio signals ch1 and ch2 to be transmitted by controlling the output (gain) from the output attenuator 34.
[0042]
The prior data storage unit 32 is connected to the transmission control unit 32 and constitutes a storage unit that stores prior data in which the position information of the transmission device 30 and the wireless transmission result information are associated with each other.
[0043]
Here, the above-mentioned advance data is obtained by a prior transmission test performed in the case of a large-scale sports broadcast program such as a marathon TV broadcast program, and can be used to specify the location where the transmission device 30 exists. ”And“ wireless transmission performance information ”indicating the wireless transmission performance at the location specified by the position information.
[0044]
For example, the prior data storage unit 32 associates with the “radio transmission performance information” indicating that the environment is unpredictable because there is a protruding building at the location A specified by the “position information”. Remember.
[0045]
Here, the “position information” may be longitude / latitude information that can be measured by GPS or the like, or may be movement distance information from a predetermined location.
[0046]
The position information measuring unit 33 is connected to the transmission control unit 31 and constitutes a position information measuring unit that measures the current position information of the transmitting device 30. For example, the position information measuring unit 33 is configured by a GPS or the like. Here, the position information measured by the position information measuring unit 33 is preferably of the same type as the “position information” stored in the pre-data storage unit 32.
[0047]
The output attenuator 34 is connected to the transmission control unit 31 and the adaptive antenna 35, and should be transmitted from the transmission device 30 to the reception device 50 via the wireless transmission line 3 in response to an instruction from the transmission control unit 31. It controls the output (gain) of data.
[0048]
The adaptive antenna 35 is connected to the transmission control unit 31 and the output attenuator 34, and controls the main beam direction 5 or the null direction 6 (see FIG. 3) and the gain in accordance with an instruction from the transmission control unit 31. Thus, the data transmitted from the output attenuator 34 is transmitted to the wireless transmission line 3 as wireless signals ch1 and ch2.
[0049]
The first receiving device 50 ₁ and the second receiving device 50 ₂ respectively include antennas 51 ₁ and 51 ₂ , receiving units 52 ₁ and 52 ₂ , required received power determination circuits 53 ₁ and 53 ₂ , and wireless transmission. Road condition detection circuits 54 ₁ and 54 ₂ are provided.
[0050]
The receiving unit 52 receives the radio signals ch1 and ch2 transmitted from the transmission device 30 via the radio transmission line 3 and the antenna 51.
[0051]
The required received power determination circuit 53 determines whether or not the received signal power of the radio signals ch1 and ch2 received by the receiving unit 52 is greater than or equal to the required received power and within a predetermined range with reference to the required received power. To do. The required received power determination circuit 53 notifies the effective radiation power control circuit 61 of the determination result.
[0052]
The wireless transmission path condition detection circuit 54 detects the wireless transmission path conditions such as the received signal power, delay profile, delay spread, and delay spread of the radio signals ch1 and ch2 received by the receiving unit 52. The wireless transmission path status detection circuit 54 notifies the effective radiated power control circuit 61 of this wireless transmission path status.
[0053]
The reception signal power intensity ratio determination circuit 60 determines whether the reception signal power intensity ratio (decibel) between the two radio signals ch1 and ch2 received by the reception unit 52 of the reception device 50 is equal to or greater than a predetermined value (decibel). It is determined whether or not. The reception signal power intensity ratio determination circuit 60 notifies the effective radiation power control circuit 61 of the determination result.
[0054]
The effective radiation power control circuit 61 is based on the determination result received from the required received power determination circuit 53 and / or the received signal power intensity ratio determination circuit 60 and the wireless transmission path status received from the wireless transmission path status detection circuit 5460. Control information generating means for generating control information for controlling the effective radiant power of the radio signal transmitted by the transmitting device 30 is configured. The effective radiation power control circuit 61 transmits the control information to the transmission device 30 via the back channel facility 2. Here, the back channel facility 2 is for connecting the effective radiation power control circuit 61 and the transmission device 30 via a wireless link.
[0055]
FIG. 4A is a diagram illustrating received signal power in the receiving device 50 when normal transmission is performed via the wireless transmission line 3, and FIG. 4B is a transmission interruption. It is a figure which shows the received signal power in the receiver 50 in the case.
[0056]
FIG. 4B shows that a transmission interruption occurs in the wireless transmission line 3 because the received signal power intensity ratio (decibel) of the two wireless signals ch1 and ch2 is less than a predetermined value (decibel). Yes.
[0057]
The configuration of the wireless transmission device according to the present invention is not limited to the configuration in the present embodiment, and any configuration can be adopted as long as the wireless transmission device according to the claims can be realized. it can.
[0058]
(Operation of the wireless transmission device according to the present embodiment)
The operation of the wireless transmission apparatus having the above configuration will be described with reference to FIG. FIG. 5 is a flowchart illustrating an operation of controlling the effective radiant power of a radio signal to be transmitted in the transmission device 30 in the wireless transmission device according to the present embodiment.
[0059]
As shown in FIG. 5, in step 500, the location information measurement unit ₃₃ 1 of the transmission device ₃₀ 1, 30 _2, 33 _2, in a predetermined cycle, by measuring the position information of each transmission device ₃₀ 1, 30 ₂ Yes.
[0060]
In step 501, the receiving units 52 ₁ and 52 ₂ of the receiving devices 50 ₁ and 50 ₂ receive the radio signals ch 1 and ch 2 transmitted from the transmitting device 30 via the wireless transmission line 3.
[0061]
In step 502, the required received power determination units 53 ₁ and 53 ₂ of the receiving devices 50 ₁ and 50 ₂ receive the received signal power of the radio signals ch1 and ch2 received by the receiving units 52 ₁ and 52 ₂ , respectively. It is determined whether the power is equal to or higher than the power and within a predetermined range based on the required received power.
[0062]
In step 503, the radio transmission path condition detection circuits 54 ₁ and 54 ₂ of the receiving apparatuses 50 ₁ and 50 ₂ receive the received signal power and delay profile of the radio signals ch1 and ch2 received by the receiving units 52 ₁ and 52 ₂ , respectively. And wireless transmission path conditions such as delay spread and delay spread.
[0063]
In step 504, the received signal power strength ratio determination circuit 60 receives the received signal power strength ratio (decibel) between the two radio signals ch1 and ch2 received by the receiving units 52 ₁ and 52 _{2 of the} receiving devices 50 ₁ and 50 _2. ) Is greater than or equal to a predetermined value (decibel).
[0064]
Here, steps 502 to 504 may be performed in parallel or in a predetermined order.
[0065]
In step 505, the effective radiant power control circuit 61 receives the determination result received from the required received power determination circuit 53 and / or the received signal power intensity ratio determination circuit 60 and the wireless transmission path condition received from the wireless transmission path condition detection circuit 54. The control information for controlling the effective radiant power of the radio signal transmitted by the transmitter 30 is generated based on the above.
[0066]
In step 506, the effective radiation power control circuit 61 transmits the control information to the transmission device 30 via the back channel facility 2.
[0067]
In step 507, the transmission control unit ₃₁ of the transmitting apparatus ₃₀ 1, 30 ₂ 1, 31 _2, back channel equipment 2 control information and transmitted from the effective radiated power control circuit 61 via a respective pre-data storage unit 32 _1, 32 and pre-data stored in the _2, based on the measured position information and the like by the location information measurement unit 33 _1, 33 _2, controls the effective radiated power of the radio signal to be transmitted.
[0068]
(Operations and effects of the wireless transmission device according to the present embodiment)
According to the wireless transmission device according to the present embodiment, in the broadcast program relay wireless transmission line 3 in which the transmission point (the transmission device 30 mounted on the mobile body 20) and the reception point 15 (the reception device 50) are specified, While maintaining the transmission characteristics of each wireless transmission line 3, it is possible to adaptively suppress unnecessary power transmission and reduce interference with adjacent channels ch1 and ch2, and reduce the probability of transmission interruption. Can do.
[0069]
In addition, according to the wireless transmission device according to the present embodiment, two mobile units (mobile relay vehicles) 20 to which adjacent frequency channels are allocated are close to each other due to marathon race development, or to the reception point 15. Even when they are arranged in the same direction, the received signal power intensity ratio (decibel) in each of the receiving devices 50 ₁ and 50 ₂ is a predetermined value determined by the modulation method and error correction method of the OFDM digital wireless transmission line 3 (Decibel) In order to suppress the effective radiation signal power of the radio signals ch1 and ch2 transmitted by the transmission devices 30 ₁ and 30 ₂ , interference between adjacent channels ch1 and ch2 can be overcome. The probability of occurrence of transmission interruption can be reduced.
[0070]
Further, according to the wireless transmission device according to the present embodiment, the transmission control unit 31 _1, 31 _2, marathon TV broadcast program such as a large-scale sports TV result of pre-transmission tests performed in the relay program (radio transmission result information ) And the effective radiation power of the radio signals ch1 and ch2 to be transmitted based on the travel distance acquired during the performance of the sports TV broadcast program and the position information such as GPS, etc. The probability of transmission interruption can be reduced.
[0071]
Further, according to the wireless transmission device according to the present embodiment, even when the reception signal power in the reception devices 50 ₁ and 50 ₂ varies from moment to moment as in the case of non-line-of-sight transmission, the reception devices 50 ₁ and 50 ₁ , 50. ₂ transmits the control information generated by the effective radiation power control circuit 61 connected to 2 to the transmission devices 30 ₁ and 30 ₂ mounted on the mobile units 20 ₁ and 20 ₂ via the back channel equipment 2. Thus, the effective radiant power of the radio signals ch1 and ch2 transmitted by the transmission devices 30 ₁ and 30 ₂ can be controlled in real time.
[0072]
【The invention's effect】
According to the present invention, it is possible to provide a wireless transmission device that reduces the probability of occurrence of transmission interruption even in a transmission environment such as non-line-of-sight transmission.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a wireless transmission device according to an embodiment of the present invention.
FIG. 2 is a diagram for explaining each function constituting a wireless transmission device according to an embodiment of the present invention.
FIG. 3 is a diagram for explaining a radio signal transmission method of an adaptive antenna of a transmission device of a radio transmission device according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating received signal power in a receiving device of a wireless transmission device according to an embodiment of the present invention.
FIG. 5 is a flowchart showing an operation of the wireless transmission device according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Fixed line 2 ... Back channel equipment 3 ... Wireless transmission line 5 ... Main beam 6 ... Null direction 10 ... Broadcasting station 15 ... Reception point 20 ... Mobile relay vehicle 30 ... Transmission apparatus 31 ... Transmission control part 32 ... Prior data storage part 33 ... Position information measuring unit 34 ... Output attenuator 35 ... Adaptive antenna 50 ... Receiving device 51 ... Antenna 52 ... Receiving unit 53 ... Required reception power determination circuit 54 ... Radio transmission path condition detection circuit 60 ... Receive signal power intensity ratio determination circuit 61 ... Effective radiation power control circuit

Claims

A first transmission device that is mounted on the first mobile body and transmits a first radio signal with a predetermined effective radiation power, and a second transmission signal that is mounted on the second mobile body and transmits a first radio signal with a predetermined effective radiation power. A wireless transmission device comprising: a second transmission device; and a reception device that receives the first wireless signal and the second wireless signal,
Or the receiving device, the received signal power of the first radio signal, and the received signal power of the second radio signal, respectively, Tsu fit in the predetermined range with the required received power or more and the necessary received power based on the A required received power determining means for determining whether or not,
The radio transmission device generates control information for controlling effective radiation power of the first radio signal and the second radio signal based on a determination result by the required received power determination unit, and generates the control Comprising control information generating means for transmitting a signal to each of the first transmission device and the second transmission device;
Each of the first transmitter and the second transmitter is
Storage means for storing prior data that is information obtained by a preliminary transmission test, and that associates the positional information of the device itself with the wireless transmission performance information indicating the wireless transmission performance at the location specified by the positional information;
Position information measuring means for measuring the current position information of the own device;
And a transmitter control unit for controlling the effective radiated power in its own device,
The transmission control means includes
Based on the current position information and the prior data, control the effective radiation power in the device itself,
A radio transmission apparatus that controls effective radiated power in its own apparatus based on the control information transmitted from the control information generating means .

A first transmission device that is mounted on the first mobile body and transmits a first radio signal with a predetermined effective radiation power, and a second transmission signal that is mounted on the second mobile body and transmits a first radio signal with a predetermined effective radiation power. A wireless transmission device comprising: a second transmission device; and a reception device that receives the first wireless signal and the second wireless signal,
The receiving device is:
Received signal power of the first radio signal, and the received signal power of the second radio signal, a required received power determining means for determining for whether required received power than der Luke,
Received signal power strength ratio between the first radio signal and the second radio signal; and a received signal power strength ratio determining means for determining whether or not that Tsu Do to or larger than a predetermined value,
Control information for controlling the effective radiant power of the first radio signal and the second radio signal based on a determination result by the required received power determination unit and the received signal power intensity ratio determination unit. Control information generation means for transmitting the generated control signal to the first transmission device and the second transmission device, respectively,
Each of the first transmitter and the second transmitter is
Storage means for storing prior data that is information obtained by a preliminary transmission test, and that associates the positional information of the device itself with the wireless transmission performance information indicating the wireless transmission performance at the location specified by the positional information;
Position information measuring means for measuring the current position information of the own device;
And a transmitter control unit for controlling the effective radiated power in its own device,
The transmission control means includes
Based on the current position information and the prior data, control the effective radiation power in the device itself,
A radio transmission apparatus that controls effective radiated power in its own apparatus based on the control information transmitted from the control information generating means .

The receiving device further includes detection means for detecting a wireless transmission path condition according to the first wireless signal received from the first transmitting device and the second wireless signal received from the second transmitting device. ,
Wherein said control information generating means, based on said radio channel state, radio transmission apparatus according to claim 1 or 2, characterized in that that generates the control information.

The first transmission device includes an adaptive antenna that transmits the first radio signal,
The transmission control means provided in the first transmission device controls effective radiation power of the first radio signal by controlling a main beam direction and gain in the adaptive antenna. The wireless transmission apparatus as described in any one of thru | or 3 .

The first transmission device includes an adaptive antenna that transmits the first radio signal,
The transmission control means provided in the first transmission device controls an effective radiation power of the first radio signal by controlling a null direction and a gain in the adaptive antenna. wireless transmission device according to any one of 3.

The first transmission device includes an output attenuator for controlling transmission signal power of the first radio signal,
The first the transmission control device provided in the transmission apparatus, by controlling the output attenuator, any one of claims 1 to 3, characterized in that controlling the effective radiated power of the first radio signal The wireless transmission device according to one item.