JP3582485B2

JP3582485B2 - Mobile communication system and its radio base station

Info

Publication number: JP3582485B2
Application number: JP2000378747A
Authority: JP
Inventors: 英一沢木
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2000-12-13
Filing date: 2000-12-13
Publication date: 2004-10-27
Anticipated expiration: 2020-12-13
Also published as: JP2002186015A

Description

【０００１】
【発明の属する技術分野】
本発明は移動通信システム及びその無線基地局に関し、特に降雨量に対応できる移動通信システム及びその無線基地局に関する。
【０００２】
【従来の技術】
この種の従来の技術について図面を参照して説明する。
【０００３】
図５は従来の移動通信システムの一例を示すブロック図である。
【０００４】
図５において、この従来例の移動通信システムは、特開平１０−６５５９６号公報の開示内容を示し、ＧＰＳアンテナ１２７とＧＰＳ受信部１２０でＧＰＳ電波を受信し、この信号は、受信信号に含まれる電波の到着時間差を検出する誤差検出部１２１に入力される。誤差検出部１２１の出力であるＧＰＳ電波の誤差分は、降雨の有無を検出する降雨センサ１２６の出力と共に送信出力制御部２２に入力される。送信出力制御部１２２は、降雨センサ１２６によって降雨が検出されると上記ＧＰＳ電波の誤差分だけ、無線基地局１１１、１１２と移動機１１０の送信出力を増大させる制御を行う送信出力制御信号を出力する。この送信出力制御信号は無線送受信部１２４に入力され、無線共通増幅部１２３で、基地局送信出力を可変する。さらに、送信出力制御信号は、無線基地局１１１、１１２から移動機１１０に対して送信する下り回線の制御チャネルに、移動機送信出力制御信号として移動機１１０に送られる。
【０００５】
移動機１１０で受信された移動機送信出力制御信号は、移動機１１０の無線送受信部１２８で受信され、送信出力制御部１２９に入力される。送信出力制御部１２９は、この入力された送信出力制御信号に応じて、移動機１１０の送信出力を制御する信号を無線送受信部１２８へ送り、移動機送信出力を可変する。
【０００６】
ＧＰＳ電波が受信できなかった場合、降雨センサ１２６が降雨を検出したかどうか判定する。降雨センサ１２６により降雨が検出されると、送信出力値に固定値Ｂを加算する。
【０００７】
移動機１１０ではこの移動機送信出力値を送信出力制御部１２９にて取り出し、無線送受信部１２８に伝達することにより移動機１１０の送信出力が制御される。
【０００８】
【発明が解決しようとする課題】
この従来例においては、ＧＰＳシステムを利用して、ＧＰＳの到着時間差を検出して、その誤差分に応じて降雨の多少を予測し、降雨センサーによって降雨の有無を検出し、その結果、降雨がある場合には、無線基地局及び移動機の送信出力増大させるシステムとなっているので、降雨のある地域にある無線基地局は降雨のない場合よりもサービスエリアの拡大が行われ、通信トラフィックの増加するという問題点がある。
【０００９】
また、ＧＰＳ電波が受信できない場合は、降雨センサーが単に降雨の有無を検出のみであり、降雨量に対応した処理をしていないという問題点がある。
【００１０】
【課題を解決するための手段】
本発明の移動通信システムのその無線基地局は、それぞれの自己の基本サービスエリア内の複数の移動端末の送受信信号を制御する複数の無線基地局と、この複数の前記無線基地局を制御しまた公衆網に接続した交換機に接続する複数の基地局制御装置とを有してなる無線通信システムにおいて、前記無線基地局から予め定められた期間の予め定められた降雨量以上を検出したことの通知を受信した前記基地局制御装置は、前記無線基地局に対して前記基本サービスエリアの範囲を予め定められた縮小サービスエリアの範囲へ縮小すべく指示する指示信号を出力し、この指示信号を受信した前記無線基地局は自己の前記基本サービスリアを前記縮小サービスエリアへ縮小すべく自己の送受信手段の送受信出力レベルを前記縮小サービスエリアに対応する予め定められたレベルに制御する制御手段を移動通信システムが備え、また、この移動通信システムにおいて、前記基地局制御装置へ、前記予め定められた期間の予め定められた降雨量以上を検出したことの通知をする前記無線基地局は、自己の前記基本サービスエリア内に駅を含む公共施設が設置されている地域を有し、且つ集中的な降雨時にトラフィックの増加が予想され、前記無線基地局は、予め定められた期間の降雨量を計量する降雨量計量手段と、この降雨量手段による計量の結果前記降雨量が予め設定された危険降雨量以上になったことを感知すると危険感知信号を出力する感知手段と、前記危険感知信号を受信すると前記基地局制御装置へ前記基本サービスエリアの危険を通報する通報手段と、前記通報の後に前記基地局制御装置からの前記基本サービスエリアから予め設定された縮小サービスエリアへ縮小すべき縮小指示信号を受信すると内臓する受信増幅器及び送信増幅器のそれぞれの増幅度を前記縮小サービスエリアになるように予め定められた増幅度に低下させるべく制御する受信・送信増幅度制御手段とを有し、また、前記感知手段は前記危険感知信号を出力した後に、前記降雨量計量手段による計量の結果前記降雨量が前記危険降雨量以下になったことを予め定められた期間継続していることを感知すると危険を解除したことを示す危険解除感知信号を出力し、前記通報手段は前記危険解除感知信号を受信すると前記基地局制御装置へ危険解除信号を通報し、前記受信・送信増幅器制御手段は前記解除信号の通報後の前記基地局制御装置から前記縮小サービスエリアから前記基本サービスエリアへ復旧させる復旧信号を受信すると前記受信増幅器及び送信増幅器のそれぞれの増幅度を前記基本サービスエリアをカバーするように復旧すべく制御する。
【００１１】
本発明の移動通信システムとその無線基地局は、それぞれの自己の基本サービスエリア内の複数の移動端末の送受信信号を制御する複数の無線基地局と、この複数の前記無線基地局を制御しまた公衆網に接続した交換機に接続する複数の基地局制御装置とを有してなる無線通信システムにおいて、前記無線基地局から予め定められたｎ（ｎ≧１の整数）期間の整数番号順に順次検出してｉ（１≦ｉ≦ｎ）期間目で予め定められたｉ番目降雨量以上を検出したことの通知を受信した前記基地局制御装置は、前記無線基地局に対して前記基本サービスエリアの範囲を前記検出された前記ｉ番目の降雨量に基づく予め定められたｉ番目縮小サービスエリアの範囲へ縮小すべく指示するｉ番目指示信号を出力し、このｉ番目指示信号を受信した前記無線基地局は自己の前記基本サービスエリアを前記ｉ番目縮小サービスエリアへ縮小すべく自己の送受信手段の送受信出力レベルを前記ｉ番目縮小サービスエリアに対応する予め定められたレベルに制御する制御手段を移動通信システムが備え、また、この移動通信システムにおいて、前記基地局制御装置へ、前記予め定められたｎ期間の整数番号順に順次検出しｉ期間目で予め定められたｉ番目降雨量以上を検出したことの通知をする前記無線基地局は、自己の前記基本サービスエリア内に駅を含む公共施設が設置されている地域を有し、且つ集中的な降雨時にトラフィックの増加が予想され、前記無線基地局は、予め定められた前記ｎ期間のそれぞれの期間の降雨量を整数番号順に順次計量する降雨量計量手段と、この降雨量計量手段による前記ｉ番目の期間での計量の結果前記降雨量が予め設定されたｉ番目危険降雨量以上になったことを感知するとｉ番目危険感知信号を出力する感知手段と、前記ｉ番目危険感知信号を受信すると前記基地局制御装置へ前記基本サービスエリアのｉ番目の危険を通報する通報手段と、前記ｉ番目の通報の後に前記基地局制御装置からの前記基本サービスエリアから予め設定されたｉ番目の縮小サービスエリアへ縮小すべきｉ番目縮小指示信号を受信すると内蔵する受信増幅器及び送信増幅器のそれぞれの増幅度を前記ｉ番目縮小サービスエリアになるように予め定められた増幅度に低下させるべく制御する受信・送信増幅器制御手段とを有し、また、前記感知手段は前記ｉ番目危険感知信号を出力した後に、前記降雨量計量手段による計量の結果前記降雨量が前記ｉ番目危険降雨量以下になったことを予め定められた期間継続していることを感知するとその危険を解除したことを示すｉ番目危険解除感知信号を出力し、前記通報手段は前記ｉ番目危険解除感知信号を受信すると前記基地局制御装置へｉ番目危険解除信号を情報し、前記受信・送信増幅器制御手段は前記危険解除の通報後の前記基地局制御装置から前記ｉ番目縮小サービスエリアからｉ−１番目の縮小サービスエリア又は前記基本サービスエリアへ復旧させるｉ番目復旧信号を受信すると前記受信増幅器及び送信増幅器のそれぞれの増幅度を前記ｉ−１番目縮小サービスエリア又は前記基本サービスエリアをカバーするように復旧すべく制御する。
【００１２】
【発明の実施の形態】
次に、本発明について図面を参照して説明する。
【００１３】
図１は本発明の第１の実施の形態の移動通信システムを示すシステム構成図、図２は本第１実施の形態における無線基地局を示すブロック図である。
【００１４】
図１において、本第１の実施の形態の移動通信システムは、複数の移動端末（ＴＳ）１−１，１−ｎと、これらの複数の移動端末（ＴＳ）が
自己のサービスエリア内にある場合に、自己のサービスエリア内の移動端末（ＴＳ）の送受信の中継制御を行う複数の無線基地局（ＮｏｄｅＢ）２−１，２−２，２−３，２−４と、これら複数の無線基地局（ＮｏｄｅＢ）２−１，２−２，２−３，２−４の管理及び無線基地局（ＮｏｄｅＢ）２−１，２−２，２−３，２−４が呼接続している移動端末（ＴＳ）を管理して、有線電話網に接続した交換機４との呼接続の制御を行う基地局制御装置（ＲＮＣ）３−１，３−２と、この基地局制御装置（ＲＮＣ）３−１，３−２に接続し、基地局制御装置（ＲＮＣ）３−１，３−２と有線電話網との呼接続の制御を行う交換機４とを備え、
無線基地局（ＮｏｄｅＢ）２−１，２−２，２−４はそれぞれアンテナ近傍に、予め定められた期間の降雨量を感知する降雨センサー２５を有し、降雨量が予め定められた以上の場合に、自己のサービスエリアの範囲を縮小すべく、送受信の増幅度を下げて送受信増幅器制御手段を有している。
【００１５】
図２において、本第１の実施の形態における基地局（ＮｏｄｅＢ）２は、図１に示す無線基地局（ＮｏｄｅＢ）２−１，２−２，２−３，２−４が総て同じ構成を有するので、その代表を示し、受信用の受信アンテナ（ＲＸ−ＡＮＴ）２１と、送信用の送信アンテナ（ＴＲＸ−ＡＮＴ）２２と、ＲＸ−ＡＮＴ２１からの受信信号を増幅する受信増幅器２３と、受信増幅器２３の状態を監視し、増幅度の増減の制御を行う受信増幅器監視制御機能部２７と、ＴＲＸ−ＡＮＴ２２へ送出する着信信号を増幅する送信増幅器機能部２８と、送信増幅器機能部２８の状態を監視し増幅度の増減の制御を行う監視制御機能部２９と、ＲＸ−ＡＮＴ２１及びＴＲＸ−ＡＮＴ２２の近傍に設置され予め定められた期間の降雨量が計量される降雨量計量タンク２４と、降雨量計量タンク２４の予め定められた期間の予め定められた複数の計量それぞれに対して感知する降雨センサー２５と、降雨センサー２５からの感知信号を監視し、予め定められた期間の予め定められた降雨量以上の感知信号を受信するとアラーム信号を送出するセンサー監視部２６と、ＲＮＣ３−１又は３−２に接続する伝送路にインタフェースする伝送路Ｉ／Ｆ部３５と、相手先が同じサービスエリアからの受信信号は復調することなく送信信号として送出し、有線電話網への信号は復調された信号を送信し、また相手先が有線電話網からの受信信号は変調して送信する無線送受信部３２と、送受信信号の変調，復調を行うベースバンド信号処理部３３と、監視制御機能部２９を介して送信系の機器の状態を監視し、センサー監視部２６からの降雨量によるアラーム信号を検出すると、送信増幅器機能部２８及び受信増幅監視制御機能部２７への増幅度を減じさせる制御信号を送出する外部監視制御部３０と、ＲＸ−ＡＮＴ２１，ＴＲＸ−ＡＮＴ２２及び交換機４へのそれぞれの送受信信号に応じて、外部監視制御部３０，無線送受信部３２，及びベースバンド信号処理部３３を制御する共通制御部３４と、無線送受信部３２の内の信号処理状態が呼接続を監視する呼接続監視装置（ＴＴＲ）３１とを有している。
【００１６】
図３は本第１の実施の形態の移動通信システムにおける無線基地局の降雨時に対するサービスエリアの縮小を示す模式図である。
【００１７】
次に、本第１の実施の形態の移動通信システムの降雨時における無線基地局（ＮｏｄｅＢ）の動作について、図１，図２及び図３を参照して説明する。
【００１８】
駅などの公共施設が集中している場所を基本サービスエリアＡ_１として持つＮｏｄｅＢ２−１に対して、この基本サービスエリアＡ_１の地域に集中的な降雨が続いているものとする。
【００１９】
このとき、ＮｏｄｅＢ２−１のＲＸ−ＡＮＴ２１及びＴＲＸ−ＡＮＴ２２の近傍にある降雨量タンク２４に予め定められた期間の降雨が溜められる。そして、降雨量計量タンク２４に予め設定された雨量の複数の感知点を降雨センサー２５が感知すると、センサー監視部２６へ通知し、センサー監視部２６が降雨センサー２５からサービスの危険度を示す予め設定された降雨量の感知点の感知をしたことを示す危険感知信号Ｓ_１を受信すると、その危険感知信号Ｓ_１を外部監視制御部３０へ通知し、外部監視制御部３０は共通制御部３４へ通知する。
【００２０】
共通制御部３４は伝送路Ｉ／Ｆ部３５を介してＲＮＣ３−１へＮｏｄｅＢ２−１の基本サービスエリアＡ_１にサービスの危険度を超す降雨があることを示す情報をＲＮＣ３−１へ送信する。
【００２１】
ＲＮＣ３−１においてはＮｏｄｅＢ２−１の基本サービスエリアＡ_１に危険度を超す降雨があるということを示す情報があることを記憶手段に記憶すると共に、ＮｏｄｅＢ２−１に対して基本サービスエリアＡ_１を予め定められた縮小エリアＡ_１ａに縮小すべきことを示す縮小指示信号を返送する。
【００２２】
ＮｏｄｅＢ２−１はＲＮＣ３−１から縮小エリアＡ_１ａへの縮小の縮小指示信号を受信すると、それを外部監視制御部３０へ通知する。外部監視制御部３０は、受信増幅器監視制御機能部２７及び監視制御機能部２９へ縮小指示信号を通知し、受信増幅器監視制御機能部２７は受信増幅部２３の増幅度を予め定められた基準に低下させる。
【００２３】
また、監視制御機能部２９は送信増幅器機能部２８に対して同様に内部にある送信増幅器の増幅度を予め定められた基準に低下させる。この結果、ＮｏｄｅＢ２−１の基本サービスエリアＡ_１は縮小サービスエリアＡ_１ａに縮小される。
【００２４】
次に、センサー監視部２６が、降雨センサー２５から危険感知信号Ｓ_１を示す降雨量よりも少ない降雨量であることを示す感知信号Ｓ_２を予め設定された期間受信すると、外部監視制御部３０へ感知信号Ｓ_２を通信する。
【００２５】
共通制御部３４は、外部監視制御部３０から感知信号Ｓ_２を受信すると危険感知信号Ｓ_１を受信した場合と同様にＲＮＣ３−１へ通知し、ＲＮＣ３−１は記憶手段に記憶しているＮｏｄｅＢ２−１が縮小エリアＡ_１ａになっていることを元の基本サービスエリアＡ_１になったことを記憶すると共に、Ｎｏｄｅ−Ｂ２−１に対して基本サービスＡ_１に復旧すべき復旧指示信号を返送する。
【００２６】
ＮｏｄｅＢ２−１はＲＮＣ３−１から復旧指示信号を受信すると、縮小指示信号を受信した場合の制御経路と同様に、受信増幅器監視制御機能部２７によって受信増幅器２３に復旧させ、送信増幅器機能２８を元の増幅度に復旧させる。この結果ＮｏｄｅＢ２−１のサービスエリアは基本サービスエリアＡ_１に復旧する。
【００２７】
以上に示したように、本第１の実施の形態においては、▲１▼降雨量計量タンク２４の予め定められた期間の降雨量が予め設定したサービスの危険度を示す量を超えるのを降雨センサー２５が感知すると、▲２▼その旨の情報が当該ＮｏｄｅＢ２−１のカバレッジ範囲を縮小サービスエリアＡ１ａに狭める。（即ち、ＮｏｄｅＢ２−１の送信電力及び受信電力のレベルを下げるべく送信増幅機能部２８及び受信増幅器２３を制御する。）
この結果、図３の破線で示した部分に位置する移動端末からの送信電波を受信（又は、その移動端末への電波の送信）することがなくなり、当該ＮｏｄｅＢ２−１にアクセスする加入端末（又は移動端末）を減少させることができる。当該ＮｏｄｅＢ２−１の基本サービスエリアＡ１から外れてしまった加入端末（又は移動端末）は、輻輳していない他のＮｏｄｅＢにアクセスすることになり、この結果、一時的にトラフィックの増加しようとする当該ＮｏｄｅＢ２−１のサービスエリアでの輻輳率を低下させることが可能となる。
【００２８】
以上の第１の実施の形態においては、降雨センサー２５が降雨量計量タンク２４のサービスエリアの危険度を示す予め定められた期間の予め設定された降雨量の一つの感知点を感知したことを示す一つの危険感知度Ｓ_１を出力することについて説明した。
【００２９】
次に示す第２の実施の形態においては、以上に示した第１の実施の形態と異なり、降雨センサー２５が、降雨量計量タンク２４のサービスエリアに対する複数の危険度を示す予め定められた期間の予め設定された複数の降雨量Ｖ_１１，Ｖ_１２，・・・Ｖ_１ｎ（Ｖ_１＜Ｖ_１１＜Ｖ_１２・・・＜Ｖ_１ｎ）のそれぞれの感知点を感知したことを示す複数の危険感知度Ｓ_１１，Ｓ_１２・・・Ｓ_１ｎを出力する。
【００３０】
図４は本発明の第２の実施の形態の移動通信システムにおける無線基地局の降雨時に対する基本サービスエリアから三つの縮小サービスエリアへ縮小する場合示す模式図である。
【００３１】
次に、本第２の実施の形態における無線基地局（ＮｏｄｅＢ）２−１の三つの縮小サービスエリアへの縮小する場合の動作について、図１，図２及び図４を参照して説明する。
【００３２】
尚、本第２の実施の形態における移動無線システムは図１に示す構成を同じとする。
【００３３】
尚、また、本第２の実施の形態における無線基地局（ＮｏｄｅＢ）２−１，２−２，２−３，２−４はそれぞれ、図２に示す構成と同じで、降雨量計量タンク２４は、予め定められた期間の予め設定された複数の降雨量Ｖ_１１，Ｖ_１２，Ｖ_１３（Ｖ_１１＜Ｖ_１２＜Ｖ_１３）に対する感知点を有し、これらの降雨量の感知点を降雨センサー２５が感知すると、これらの感知点に対して、それぞれ危険感知信号Ｓ_１１，Ｓ_１２，Ｓ_１３をセンサー監視部２６へ出力する構成になっている。
【００３４】
更に、受信増幅器２３は受信増幅器監視制御機能部２７によって、及び送信増幅器機能部２８は監視制御機能部２９によって、それぞれ外部監視制御部３０の制御の基に、外部監視制御部３０が危険感知信号Ｓ_１１，Ｓ_１２，Ｓ_１３を受信するに応じて予め定められた増幅度に増減することができる構成になっている。
【００３５】
先ず、最初に降雨センサー２５が降雨量計量タンク２４の降雨量Ｖ_１１の感知点を感知すると危険感知信号Ｓ_１１をセンサー監視部２６へ出力する。
【００３６】
この後の制御動作は、第１の実施の形態におけるセンサー監視部２６が危険感知信号Ｓ_１を受信した場合と同じで、最終的に受信増幅器２３及び送信増幅機能部２８の増幅度が危険感知信号Ｓ_１１に対応した増幅度になるべく制御され、その結果、ＮｏｄｅＢ２−１のサービスエリアは、図４に示すように基本サービスエリアＡ_１から縮小サービスエリアＡ_１１に縮小される。
【００３７】
以下、降雨量計量タンク２４の予め定められた期間の降雨量Ｖ_１１がＶ_１２，Ｖ_１３と増量するたびに、降雨センサー２５が危険感知信号Ｓ_１２，Ｓ_１３を出力し、その結果、降雨量Ｖ_１１の場合と同様な制御手順によって、ＮｏｄｅＢのサービスエリアは、図４に示すように縮小サービスエリアＡ_１１からＡ_１２，Ａ_１３へと縮小される。
【００３８】
尚、降雨量が少なくなった場合には、第１の実施の形態の場合と同様な復旧制御手順によって縮小サービスＡ_１３→Ａ_１２→Ａ_１１→Ａ_１へと段階的にサービスエリアを復旧していく。
【００３９】
このように、本第２の実施の形態においては、降雨量に応じて段階的にサービスエリアを縮小，復旧していくので、ユーザーに対してきめ細かなサービスを提供することができる。
【００４０】
【発明の効果】
以上説明したように本発明は、それぞれの自己の基本サービスエリア内の複数の移動端末の送受信信号を制御する複数の無線基地局と、この複数の無線基地局を制御しまた公衆網に接続した交換機に接続する複数の基地局制御装置とを有してなる無線通信システムにおいて、無線基地局から予め定められた期間の予め定められた降雨量以上を検出したことの通知を受信した前記基地局制御装置は、無線基地局に対して前記基本サービスエリアの範囲を予め定められた縮小サービスエリアの範囲、縮小すべく指示する指示番号を出力し、この指示信号を受信した無線基地局は自己の基本サービスエリアを前記縮小サービスエリアへ縮小すべく自己の送受信手段の送受信出力レベルを縮小サービスエリアに対応する予め定められたレベルに制御する制御手段を備えることにより、以下に示す効果を得ることができる。
【００４１】
第１の効果は、ＮｏｄｅＢは縮小サービスエリア外の移動端末からの送信電波を受信（又はその移動端末への電波の送信）することがなくなり、当該ＮｏｄｅＢにアクセスする移動端末を減少させることができ、当該ＮｏｄｅＢの基本サービスエリアから外れた移動端末は他のＮｏｄｅＢにアクセスすることとなり、この結果、一時的にトラフィックが増加しようとする当該ＮｏｄｅＢのサービスエリアでの輻輳率を低下させることができる。
【００４２】
第２の効果は、第１の効果の派生的な効果として、より多くの人々が同時に通信できるようになるため、通信事業者は、本件発明を利用しない場合に比べてより多くの通話料金を取ることができる。
【００４３】
第３の効果として、第２の効果とも関連するが、トラフィック増加時にＮｏｄｅＢの送信電力を下げるので、通話料金の増加と相俟って、通信事業者側のコスト・パフォーマンスを増加させることに寄与する。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態の移動通信システムを示すシステム構成図である。
【図２】本第１の実施の形態の移動通信システムにおける無線基地局を示すブロック図である。
【図３】本第１の実施の形態の移動通信システムにおける無線基地局の降雨時に対するサービスエリアの縮小を示す模式図である。
【図４】本発明の第２の実施の形態の移動通信システムにおける無線基地局の降雨時に対する基本サービスエリアから三つの縮小サービスエリアへ縮小する場合を示す模式図である。
【図５】従来の移動通信システムにおける無線基地局の一例を示すブロック図である。
【符号の説明】
１−１，１−ｎ移動端末（ＴＳ）
２，２−１，２−２，２−３，２−４無線基地局（ＮｏｄｅＢ）
３−１，３−２基地局制御装置（ＲＮＣ）
４交換機
２１受信アンテナ（ＲＸ−ＡＮＴ）
２２送信アンテナ（ＴＲＸ−ＡＮＴ）
２３受信増幅器
２４降雨量計量タンク
２５降雨センサー
２６センサー監視部
２７受信増幅器監視制御機能部
２８送信増幅器機能部
２９監視制御機能部
３０外部監視制御部
３１呼接続監視装置（ＴＴＲ）
３２無線送受信部
３３ベースバンド信号処理部
３４共通制御部
３５伝送路Ｉ／Ｆ部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mobile communication system and a radio base station thereof, and more particularly, to a mobile communication system and a radio base station thereof capable of coping with rainfall.
[0002]
[Prior art]
This type of related art will be described with reference to the drawings.
[0003]
FIG. 5 is a block diagram showing an example of a conventional mobile communication system.
[0004]
In FIG. 5, this prior art mobile communication system shows the disclosure of Japanese Patent Application Laid-Open No. H10-65596, in which a GPS antenna 127 and a GPS receiver 120 receive a GPS radio wave, and this signal is included in a received signal. The signal is input to an error detection unit 121 that detects a difference between arrival times of radio waves. The error of the GPS radio wave output from the error detection unit 121 is input to the transmission output control unit 22 together with the output of the rain sensor 126 for detecting the presence or absence of rain. When the rainfall is detected by the rainfall sensor 126, the transmission output control unit 122 outputs a transmission output control signal for controlling to increase the transmission output of the radio base stations 111 and 112 and the mobile device 110 by the error of the GPS radio wave. I do. This transmission output control signal is input to the wireless transmission / reception unit 124, and the wireless common amplification unit 123 changes the base station transmission output. Further, the transmission output control signal is transmitted to mobile station 110 as a mobile station transmission output control signal on a downlink control channel transmitted from radio base stations 111 and 112 to mobile station 110.
[0005]
The mobile device transmission output control signal received by mobile device 110 is received by wireless transmission / reception section 128 of mobile device 110 and input to transmission output control section 129. The transmission output control unit 129 sends a signal for controlling the transmission output of the mobile device 110 to the wireless transmission / reception unit 128 according to the input transmission output control signal, and varies the mobile device transmission output.
[0006]
If the GPS radio wave has not been received, it is determined whether the rainfall sensor 126 has detected rainfall. When rainfall is detected by the rainfall sensor 126, a fixed value B is added to the transmission output value.
[0007]
In the mobile device 110, the transmission output of the mobile device 110 is controlled by taking out the transmission output value of the mobile device by the transmission output control unit 129 and transmitting it to the wireless transmission / reception unit 128.
[0008]
[Problems to be solved by the invention]
In this conventional example, a GPS system is used to detect a GPS arrival time difference, to predict the amount of rain according to the error, and to detect the presence or absence of rain by a rain sensor. In some cases, the transmission output of the radio base station and the mobile device is increased, so that the radio base station in an area with rainfall expands the service area as compared with the case without rainfall, and the communication traffic increases. There is a problem that it increases.
[0009]
Further, when GPS radio waves cannot be received, there is a problem that the rainfall sensor simply detects the presence or absence of rainfall and does not perform processing corresponding to the amount of rainfall.
[0010]
[Means for Solving the Problems]
The wireless base station of the mobile communication system of the present invention, the respective own basic service area multiple radio base station that controls the plurality of transmitting and receiving signals of the mobile terminal in, multiple this the radio base station And controlling a plurality of base station controllers connected to an exchange connected to a public network in a wireless communication system, wherein a predetermined amount of rainfall or more is detected from the wireless base station for a predetermined period. the said base station controller which has received the notification outputs an instruction signal for instructing so as to reduce the range of the said basic service reduced coverage area to a predetermined range of area to the radio base station, the The radio base station, having received the instruction signal, reduces the transmission / reception output level of its transmission / reception means to reduce the basic service area of the base station to the reduced service area. A control means for controlling the corresponding predetermined level is a mobile communication system, and in the mobile communication system, wherein the base station controller, detects the higher rainfall predetermined said predetermined period the radio base station to the notification that has an area of public facilities, including the station self of the basic service area is provided, an increase in traffic is expected and when intensive rainfall, The wireless base station, when sensing that the rainfall amount measuring means for measuring the rainfall amount of a predetermined period, and that the rainfall amount as a result of the measurement by the rainfall means has become equal to or more than a predetermined dangerous rainfall amount Sensing means for outputting a danger sensing signal, notifying means for notifying the base station controller of the danger of the basic service area upon receiving the danger sensing signal, and When a reduction instruction signal to be reduced from the basic service area to the preset reduction service area from the base station control device is received, the respective amplification degrees of the built-in receiving amplifier and transmission amplifier are set in advance so as to become the reduced service area. Reception / transmission amplification degree control means for controlling to reduce the amplification degree to a predetermined amplification degree, and the sensing means outputs the danger sensing signal, and then the rainfall amount is measured by the rainfall amount measurement means. When it is detected that the rainfall has become equal to or less than the dangerous rainfall for a predetermined period, a danger release detection signal indicating that the danger has been released is output, and the reporting means receives the danger release detection signal. Then, a danger release signal is reported to the base station controller, and the receiving / transmitting amplifier control means transmits the danger release signal to the base station controller after reporting the release signal. Upon receiving a restoration signal for restoring from the reduced service area to the basic service area, control is performed to restore the respective amplification factors of the reception amplifier and the transmission amplifier so as to cover the basic service area.
[0011]
The wireless base station and the mobile communication system of the present invention, the respective own basic service area multiple radio base station that controls the plurality of transmitting and receiving signals of the mobile terminal in, multiple this the radio base station And a plurality of base station controllers connected to an exchange connected to a public network, and a predetermined integer (n ≧ 1 integer) period of integers from the wireless base station. sequentially detects and i (1 ≦ i ≦ n) period th the base station controller which has received the notification of the detection of the predetermined or more i-th rainfall in the numerical order, the mobile station to the radio base station An i-th instruction signal for instructing to reduce the range of the basic service area to a predetermined i-th reduction service area based on the detected i-th rainfall amount is output, and the i-th instruction signal is received. Said nothing The base station moves control means for controlling the transmission / reception output level of its own transmission / reception means to a predetermined level corresponding to the i-th reduced service area in order to reduce its own basic service area to the i-th reduced service area. A communication system is provided, and in this mobile communication system, the base station control device sequentially detects the integer number of the predetermined n period and sequentially detects the predetermined i-th rainfall or more in the i-th period. the radio base station to a notification that includes a region where public facilities, including the station self of the basic service area is provided, an increase in traffic is expected and when intensive rainfall, the The radio base station includes: a rainfall amount measuring unit that sequentially measures rainfall in each of the predetermined n periods in the order of integer numbers; and a rainfall amount measuring unit. Sensing means for outputting an i-th danger sensing signal when sensing that the rainfall is equal to or greater than a preset i-th danger rainfall as a result of the measurement in the i-th period; Reporting means for notifying the base station controller of the i-th danger of the basic service area upon receipt; and i-th preset from the basic service area from the base station controller from the base station controller after the i-th report. Upon receiving the i-th reduction instruction signal to be reduced to the reduced service area, control is performed to reduce the respective amplifications of the built-in receiving amplifier and transmission amplifier to a predetermined amplification so as to become the i-th reduced service area. Receiving / transmitting amplifier control means, wherein the sensing means outputs the i-th danger detection signal and then outputs the weighing result by the rainfall measuring means. When it is detected that the rainfall has become equal to or less than the i-th dangerous rainfall for a predetermined period, an i-th danger release detection signal indicating that the danger has been released is output, and the notification is issued. The means informs the base station controller of the i-th danger release signal upon receiving the i-th danger release detection signal, and the receiving / transmitting amplifier control means transmits the i-th danger release detection signal from the base station controller after the danger release notification. Upon receiving an i-th restoration signal for restoring from the i-th reduced service area to the (i-1) -th reduced service area or the basic service area, the amplification degree of each of the reception amplifier and the transmission amplifier is increased to the (i-1) -th reduced service area or the Control is performed to restore to cover the basic service area.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described with reference to the drawings.
[0013]
FIG. 1 is a system configuration diagram illustrating a mobile communication system according to a first embodiment of the present invention, and FIG. 2 is a block diagram illustrating a wireless base station according to the first embodiment.
[0014]
In FIG. 1, the mobile communication system according to the first embodiment has a plurality of mobile terminals (TS) 1-1 and 1-n, and the plurality of mobile terminals (TS) are within their own service area. In this case, a plurality of radio base stations (NodeBs) 2-1 2-2-3, 2-3, and 2-4 that perform relay control of transmission and reception of mobile terminals (TSs) in their service areas, and the plurality of radio base stations Management of base stations (NodeB) 2-1, 2-2, 2-3, 2-4 and call connection of radio base stations (NodeB) 2-1, 2-2, 2-3, 2-4. Base station controllers (RNC) 3-1 and 3-2 for managing mobile terminals (TS) and controlling call connection with the exchange 4 connected to the wired telephone network, and the base station controllers (RNC) 3-1 and 3-2, and call connection between the base station controller (RNC) 3-1 and 3-2 and the wired telephone network And a switch 4 for controlling,
Each of the radio base stations (NodeB) 2-1, 2-2, and 2-4 has a rainfall sensor 25 for detecting a rainfall amount for a predetermined period in the vicinity of the antenna. In this case, in order to reduce the range of its own service area, transmission / reception amplifier control means is provided by lowering transmission / reception amplification.
[0015]
2, the base station (NodeB) 2 according to the first embodiment has the same configuration as the wireless base stations (NodeB) 2-1, 2-2, 2-3, and 2-4 shown in FIG. Therefore, a representative thereof is shown, and a reception antenna (RX-ANT) 21 for reception, a transmission antenna (TRX-ANT) 22 for transmission, a reception amplifier 23 for amplifying a reception signal from the RX-ANT 21, A reception amplifier monitoring control function unit 27 that monitors the state of the reception amplifier 23 and controls the increase or decrease of the amplification degree, a transmission amplifier function unit 28 that amplifies an incoming signal to be sent to the TRX-ANT 22, and a transmission amplifier function unit 28 A monitoring and control function unit 29 for monitoring the state and controlling the increase and decrease of the amplification degree; and a rainfall measuring tank installed near the RX-ANT21 and the TRX-ANT22 for measuring the rainfall during a predetermined period. 4, a rain sensor 25 that senses each of a plurality of predetermined weighings of the rainfall measuring tank 24 for a predetermined period, and a sensing signal from the rain sensor 25 that is monitored for a predetermined period. A sensor monitoring unit 26 that sends out an alarm signal when a sensing signal equal to or greater than a predetermined rainfall is received, a transmission line I / F unit 35 that interfaces with a transmission line connected to the RNC 3-1 or 3-2, However, the signal received from the same service area is transmitted as a transmission signal without demodulation, the signal to the wired telephone network is transmitted as a demodulated signal, and the signal received from the other party is modulated and transmitted. A transmission / reception unit 32, a baseband signal processing unit 33 for performing modulation and demodulation of transmission / reception signals, and a monitoring / control function unit 29 for monitoring the status of the transmission system device, Upon detecting an alarm signal due to the amount of rainfall from the viewing unit 26, an external monitoring control unit 30 that sends a control signal to the transmission amplifier function unit 28 and the reception amplification monitoring control function unit 27 to reduce the amplification degree, and the RX-ANT 21, A common control unit 34 that controls the external monitoring control unit 30, the radio transmission / reception unit 32, and the baseband signal processing unit 33 according to the transmission / reception signals to the TRX-ANT 22 and the exchange 4, The signal processing state has a call connection monitoring device (TTR) 31 for monitoring the call connection.
[0016]
FIG. 3 is a schematic diagram showing the reduction of the service area when the radio base station rains in the mobile communication system according to the first embodiment.
[0017]
Next, the operation of the radio base station (NodeB) during rainfall of the mobile communication system according to the first embodiment will be described with reference to FIGS. 1, 2, and 3. FIG.
[0018]
Against NodeB2-1 with the location where the public facilities such as stations are concentrated as a basic service area A _1, it is assumed that followed by intensive rainfall in the area of this basic service area A _1.
[0019]
At this time, rain for a predetermined period is accumulated in the rainfall tank 24 near the RX-ANT 21 and the TRX-ANT 22 of the NodeB 2-1. When the rainfall sensor 25 detects a plurality of sensing points of the rainfall set in the rainfall measuring tank 24 in advance, the rainfall sensor 25 notifies the sensor monitoring unit 26, and the sensor monitoring unit 26 indicates the risk of the service from the rainfall sensor 25 in advance. Upon receiving the danger sensing signal S ₁ indicating that the set rainfall sensing point has been sensed, the danger sensing signal S ₁ is notified to the external monitoring and control unit 30. Notify to
[0020]
The common control unit 34 transmits information indicating that there is rain in excess of risk of the service to the basic service area _{A 1} of RNC3-1 to NodeB2-1 via a transmission path I / F unit 35 to RNC3-1.
[0021]
Stores in the storage means that there is information indicating that there is rain in excess of risk in the basic service area _{A 1} of NodeB2-1 in RNC3-1, the basic service area _{A 1} relative NodeB2-1 A reduction instruction signal indicating that the image should be reduced to a predetermined reduction area _A1a is returned.
[0022]
NodeB2-1 Upon receiving the reduction instruction signal reduction to the reduced area _{A 1a} from RNC3-1, and notifies it to the external monitoring control unit 30. The external monitoring control unit 30 notifies the reception amplifier monitoring control function unit 27 and the monitoring control function unit 29 of the reduction instruction signal, and the reception amplifier monitoring control function unit 27 sets the amplification degree of the reception amplification unit 23 to a predetermined reference. Lower.
[0023]
Further, the monitoring control function unit 29 similarly lowers the amplification degree of the transmission amplifier inside the transmission amplifier function unit 28 to a predetermined reference. As a result, the basic service area _{A 1} of NodeB2-1 is reduced to the reduced service area _{A 1a.}
[0024]
Then, when the sensor monitoring unit 26, sensed signal S ₂ received preset period indicating a less rainfall than rainfall showing a danger sensing signals S ₁ from the rain sensor 25, an external monitoring control unit 30 communicating sensed signals _{S 2} to.
[0025]
The common control unit 34 notifies to the same manner as when receiving the danger sensing signals _{S 1} receives the sensing signal _{S 2} from the external monitoring control unit 30 RNC3-1, RNC3-1 is stored in the storage means NodeB2 -1 with stores that that was the source of the basic service area _{a 1} a that is a reduced area _{a 1a,} returning the recovery instruction signal to be restored to the basic service _{a 1} with respect to Node-B 2 - 1 I do.
[0026]
When receiving the restoration instruction signal from the RNC 3-1, the NodeB 2-1 restores the reception amplifier 23 by the reception amplifier monitoring and control function unit 27 and restores the transmission amplifier function 28 as in the control path when the reduction instruction signal is received. To the degree of amplification. Service area of this result NodeB2-1 is to restore the basic service area _{A 1.}
[0027]
As described above, in the first embodiment, (1) it is determined that the amount of rainfall of the rainfall amount measuring tank 24 during a predetermined period exceeds the amount indicating the degree of risk of the preset service. When the sensor 25 senses, (2) the information to that effect narrows the coverage range of the Node B 2-1 to the reduced service area A1a. (That is, the transmission amplification function unit 28 and the reception amplifier 23 are controlled to reduce the levels of the transmission power and the reception power of the NodeB 2-1.)
As a result, the transmission radio wave from the mobile terminal located at the portion shown by the broken line in FIG. 3 is not received (or the radio wave is transmitted to the mobile terminal), and the subscribed terminal (or the subscribed terminal that accesses the NodeB 2-1) Mobile terminals). The subscribed terminal (or mobile terminal) that has deviated from the basic service area A1 of the NodeB 2-1 accesses another non-congested NodeB, and as a result, the traffic that temporarily increases the traffic The congestion rate in the service area of NodeB 2-1 can be reduced.
[0028]
In the first embodiment described above, it is assumed that the rainfall sensor 25 has sensed one sensing point of a predetermined amount of rainfall for a predetermined period indicating the degree of risk of the service area of the rainfall amount measuring tank 24. has been described to output a single risk sensing degree S ₁ shown.
[0029]
In the second embodiment described below, unlike the first embodiment described above, the rainfall sensor 25 detects a plurality of danger levels for the service area of the rainfall amount measuring tank 24 for a predetermined period. a plurality of rainfall _V _11, V ₁₂ which is previously _{set, and} a plurality of indicating the sensing of each sensing point _{_{_{··· V 1n (V 1 <V}}} 11 <V 12 ··· <V 1n) risk and it outputs the sensing of _{_{_{S 11, S 12 ··· S 1n}}} .
[0030]
FIG. 4 is a schematic diagram showing a case where a radio base station is reduced from a basic service area to three reduced service areas during rainfall in the mobile communication system according to the second embodiment of the present invention.
[0031]
Next, an operation in the case where the wireless base station (NodeB) 2-1 is reduced to three reduced service areas in the second embodiment will be described with reference to FIG. 1, FIG. 2 and FIG.
[0032]
The mobile radio system according to the second embodiment has the same configuration as that shown in FIG.
[0033]
The radio base stations (NodeB) 2-1, 2-2, 2-3, and 2-4 in the second embodiment have the same configuration as that shown in FIG. Has sensing points for a plurality of predetermined rainfall amounts V ₁₁ , V _12, V ₁₃ (V ₁₁ <V ₁₂ <V ₁₃ ) during a predetermined period, and sets the sensing points of these rainfall amounts to rain. When the sensor 25 senses, the danger sensing signals S ₁₁ , S ₁₂ , and S ₁₃ are output to the sensor monitoring unit 26 for these sensing points, respectively.
[0034]
Further, the receiving amplifier 23 is controlled by the receiving amplifier monitoring control function unit 27, and the transmitting amplifier function unit 28 is controlled by the monitoring control function unit 29. The configuration is such that the amplification degree can be increased or decreased to a predetermined amplification degree in response to receiving S ₁₁ , S ₁₂ , and S ₁₃ .
[0035]
First, when the rain sensor 25 first detects the sensing point of the rain amount V _{11 in} the rain amount measuring tank 24, it outputs a danger detection signal S ₁₁ to the sensor monitoring unit 26.
[0036]
Control operation after this is the same as the sensor monitoring unit 26 in the first embodiment receives a danger sensing signal S _1, the amplification degree sensing risk of eventually receiving amplifier 23 and transmitting amplifier function part 28 signal _{S 11} as much as possible the control of the amplification degree corresponding to a result, the service area of NodeB2-1 is reduced to the reduced service area _{a 11} from the basic service area _{a 1} as shown in FIG.
[0037]
Hereinafter, each time the rainfall _{V 11} a predetermined period of rainfall measuring tank 24 is increased with _V _{12, V 13,} rain sensor 25 outputs a danger sensing signal _S _{12, S 13,} as a result, rain the same control procedure as the amount _{V 11,} the service area of the NodeB is reduced from the reduced service area _{a 11,} as shown in FIG. 4 to _a _{12, a 13.}
[0038]
When the amount of rainfall decreases, the service area is restored stepwise from the reduced service A ₁₃ → A ₁₂ → A ₁₁ → A ₁ by the same restoration control procedure as in the first embodiment. To go.
[0039]
As described above, in the second embodiment, the service area is gradually reduced and restored in accordance with the amount of rainfall, so that a fine-grained service can be provided to the user.
[0040]
【The invention's effect】
The present invention described above, the multiple radio base station that controls the plurality of transmitting and receiving signals of the mobile terminal of each of its basic service area, to control the multiple radio base stations this also public In a wireless communication system having a plurality of base station controllers connected to an exchange connected to a network, a notification that a predetermined amount of rainfall or more has been detected for a predetermined period is received from a wireless base station. and said base station controller is, the basic service range predetermined range of the reduction service area the area the radio base station, and outputs an instruction number that instructs so as to reduce, radio base that receives this instruction signal The station controls the transmission / reception output level of its transmission / reception means to a predetermined level corresponding to the reduced service area in order to reduce its own basic service area to the reduced service area. By providing control means, it is possible to obtain the following effects.
[0041]
The first effect is that the NodeB does not receive a radio wave transmitted from a mobile terminal outside the reduced service area (or transmits a radio wave to the mobile terminal), and the number of mobile terminals accessing the NodeB can be reduced. Then, a mobile terminal deviating from the basic service area of the NodeB accesses another NodeB, and as a result, it is possible to reduce the congestion rate in the service area of the NodeB where the traffic is going to increase temporarily.
[0042]
The second effect is, as a secondary effect of the first effect, that a larger number of people can communicate at the same time, so that the communication carrier has to pay more call charges than when the present invention is not used. Can be taken.
[0043]
As a third effect, which is related to the second effect, the transmission power of the NodeB is reduced when the traffic increases, which contributes to an increase in the cost performance of the communication carrier in conjunction with an increase in the call charge. I do.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram showing a mobile communication system according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a radio base station in the mobile communication system according to the first embodiment.
FIG. 3 is a schematic diagram showing a reduction of a service area when a radio base station rains in the mobile communication system according to the first embodiment.
FIG. 4 is a schematic diagram showing a case where a radio base station is reduced from a basic service area to three reduced service areas when raining in a mobile communication system according to a second embodiment of the present invention.
FIG. 5 is a block diagram showing an example of a radio base station in a conventional mobile communication system.
[Explanation of symbols]
1-1, 1-n mobile terminal (TS)
2,2-1,2-2,2-3,2-4 Radio base station (NodeB)
3-1 and 3-2 base station controller (RNC)
4 Exchange 21 Receiving antenna (RX-ANT)
22 transmitting antenna (TRX-ANT)
23 Receiving amplifier 24 Rainfall measuring tank 25 Rainfall sensor 26 Sensor monitoring unit 27 Receiving amplifier monitoring control function unit 28 Transmission amplifier function unit 29 Monitoring control function unit 30 External monitoring control unit 31 Call connection monitoring device (TTR)
32 wireless transmission / reception section 33 baseband signal processing section 34 common control section 35 transmission path I / F section

Claims

And each of its basic service area multiple radio base station that controls the plurality of transmitting and receiving signals of the mobile terminal in, and controls the radio base station of the multiple This also connected to the exchange connected to a public network In a wireless communication system having a plurality of base station control devices,
Wherein said base station controller which has received the notification of the detection of the predetermined or more amount of rainfall predetermined period from the radio base station, a predetermined range of the basic service area to the radio base station outputs an instruction signal for instructing so as to reduce the range of the reduced service area that is, the radio base station that receives this instruction signal of its own transceiver means so as to reduce the basic service rear self to the reduced service area wireless communication system characterized in that it comprises control means for controlling the transmission and reception output level to a predetermined level corresponding to the reduced service area.

A rainfall amount measuring means for measuring a rainfall amount for a predetermined period, and a danger sensing signal when the rainfall amount is detected to be equal to or greater than a predetermined dangerous rainfall amount as a result of the measurement by the rainfall amount means. Detecting means, notifying means for notifying the base station controller of the danger of the basic service area upon receiving the danger sensing signal, and presetting from the basic service area from the base station control apparatus after the notification. Upon receiving a reduction instruction signal to be reduced to the reduction service area, reception / transmission amplification for controlling the amplification of each of the built-in reception amplifier and transmission amplifier to be reduced to a predetermined amplification degree so as to become the reduction service area. The radio base station according to claim 1, further comprising a degree control unit.

After outputting the danger sensing signal, the sensing means detects a danger when the rainfall amount measurement means detects that the rainfall has become equal to or less than the dangerous rainfall for a predetermined period of time. A danger release detection signal indicating that the danger has been released, the notifying unit, upon receiving the danger release detection signal, notifies the base station controller of a danger release signal, and the receiving / transmitting amplifier control unit outputs the release signal. Receiving a restoration signal from the base station controller after the notification of the restoration from the reduced service area to the basic service area, restores the respective amplification factors of the reception amplifier and the transmission amplifier so as to cover the basic service area. 3. The radio base station of the mobile communication system according to claim 2, wherein the radio base station performs control as needed.

And each of its basic service area multiple radio base station that controls the plurality of transmitting and receiving signals of the mobile terminal in, and controls the radio base station of the multiple This also connected to the exchange connected to a public network In a wireless communication system having a plurality of base station control devices,
The wireless base station sequentially detects the predetermined n (integer of n ≧ 1) in the order of integer numbers and detects the predetermined i-th or more rainfall in the i-th (1 ≦ i ≦ n) period. The base station control device, which has received the notification of the above , moves the range of the basic service area to the radio base station to a predetermined range of the i-th reduced service area based on the detected i-th rainfall amount. The radio base station outputs an i-th instruction signal for instructing reduction, and the radio base station receiving the i-th instruction signal transmits / receives the transmission / reception output of its own transmission / reception means to reduce its basic service area to the i-th reduction service area. A wireless communication system comprising control means for controlling a level to a predetermined level corresponding to the i-th reduced service area.

Rainfall measuring means for sequentially measuring the rainfall in each of the predetermined n periods in the order of integer numbers, and the rainfall is set in advance as a result of the measurement in the i-th period by the rainfall measuring means. Sensing means for outputting an i-th danger detection signal when the i-th danger rainfall is detected to be greater than or equal to the i-th danger rainfall, and receiving the i-th danger detection signal from the base station controller to the i-th danger of the basic service area. And a notification unit for receiving an i-th reduction instruction signal to be reduced from the basic service area to the preset i-th reduction service area from the base station controller after the i-th notification. Reception / transmission control for reducing the amplification of each of the reception amplifier and the transmission amplifier to a predetermined amplification so as to be in the i-th reduced service area. The radio base station of the mobile communication system according to claim 4, characterized in that it comprises an amplifier control means.

After outputting the i-th danger detection signal, the sensing means has continued for a predetermined period of time such that the rainfall has become equal to or less than the i-th dangerous rainfall as a result of the measurement by the rainfall measurement means. , And outputs an i-th danger release detection signal indicating that the danger has been released, and the notification means informs the base station controller of the i-th danger release signal when the i-th danger release detection signal is received, The receiving / transmitting amplifier control means receives an i-th restoration signal for restoring from the i-th reduced service area to the (i-1) -th reduced service area or the basic service area from the base station controller after the danger release notification. Then, the respective amplification factors of the reception amplifier and the transmission amplifier are set so as to cover the (i-1) th reduced service area or the basic service area. The radio base station of the mobile communication system according to claim 5, wherein the controller controls so as to old.

Notify the base station control device that the predetermined rainfall or more has been detected for the predetermined period, or detect the integer number of the predetermined n period sequentially in the i-th period. the radio base station for a notification of the detection of the predetermined or more i-th rainfall has areas where public facilities including stations in self of the basic service area are installed, and concentrated such claim 1 increased traffic during rainfall and wherein the Turkey is expected, or, of 4, wherein the wireless communication system.