JP2004159115A

JP2004159115A - Cellular telephone terminal, dual band cellular telephone system and dual band changeover method for same

Info

Publication number: JP2004159115A
Application number: JP2002323249A
Authority: JP
Inventors: Takeshi Shimizu; 猛史清水
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2002-11-07
Filing date: 2002-11-07
Publication date: 2004-06-03
Anticipated expiration: 2022-11-07
Also published as: JP4321044B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cellular telephone terminal allowing to reduce current consumption by reducing time for changing-over each system and by improving operability. <P>SOLUTION: The BSs (Base Station) 61-63, 71-73 of a PDC network 100 and an IMT network 200 conduct level measurement for RSSI to optimize the level measurement in accordance with dead channel information to decide the arrangement of BCCHs of respective systems, a PDC radio system and an IMT radio system by an IMT/PDC BCCH control section 2. The IMT/PDC BCCH control section 2 synchronizes a clock between the systems, the PDC radio system and the IMT radio system, and informs the BCCH transmission frequency of an adjacent cell and relative timing to the terminal side by the BCCH. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は携帯電話端末、デュアルバンド携帯電話システム及びそれらに用いるデュアルバンド切替方法に関し、特に第３世代の携帯電話システムであるＩＭＴ（ＩｎｔｅｒｎａｔｉｏｎａｌＭｏｂｉｌｅＴｅｌｅｃｏｍｍｕｎｉｃａｔｉｏｎｓ）機能及び既存の携帯電話システムであるＰＤＣ（ＰｅｒｓｏｎａｌＤｉｇｉｔａｌＣｅｌｌｕｌａｒ）機能の両方を備える携帯電話端末に関する。
【０００２】
【従来の技術】
第３世代の携帯電話システムであるＩＭＴ機能と、既存の携帯電話システムであるＰＤＣ機能との両方を備える端末においては、無線システムの違いからそれぞれ無線部を持つ必要がある（例えば、特許文献１〜３参照）。
【０００３】
ＩＭＴ機能とＰＤＣ機能とを持つデュアルバンド携帯電話端末の開発に当たり、ＩＭＴ切替え時間の短縮は商品力にとっても大きな要因となり、それらＩＭＴ無線信号とＰＤＣ無線信号とを同時に待受けた場合、ＩＭＴ無線機とＰＤＣ無線機とを同時に動作させる必要があり、消費電流に影響がある。
【０００４】
また、この種の異なる無線システムの切替え方法としては、２つのシステム制御周波数を記憶し、サービスエリア外に移動した場合、メモリに予め保持してある、制御周波数に基づいてセルの検索動作を行い、メモリに予め保持している周波数がない場合に全制御周波数のスキャンを実施する方法がある（例えば、特許文献４参照）。
【０００５】
これによって、上記の無線システムの切替え方法では、リスト内に制御チャネル情報があれば、スキャン動作を省略することができ、消費電流の軽減及び切替えの高速化が可能になる。
【０００６】
【特許文献１】
特開昭６３−２０３０２５号公報（第８〜１２頁、図１）
【特許文献２】
特開平０５−１０２９２３号公報（第２〜４頁、図２）
【特許文献３】
特開平０９−０５１３２１号公報（第３〜６頁、図１）
【特許文献４】
特開平１１−２９８９６４号公報（第５，６頁、図１）
【０００７】
【発明が解決しようとする課題】
上述した従来の携帯電話システムでは、ＩＭＴ無線システムとＰＤＣ無線システムとを切替える時、それらＩＭＴ無線信号とＰＤＣ無線信号とを同時に待受ける場合、ＩＭＴ無線機とＰＤＣ無線機とを同時に動作させる必要があるので、消費電流が増加し、待ち受け時間が短かくなってしまうという問題がある。携帯電話端末においては消費電流の増加が商品力の低下につながり、大きな問題となる。
【０００８】
そこで、本発明の目的は上記の問題点を解消し、ＩＭＴ無線システムとＰＤＣ無線システムとを切替える時間の短縮と操作性の向上とを図ることができ、消費電流を削減することができる携帯電話端末、デュアルバンド携帯電話システム及びそれらに用いるデュアルバンド切替方法を提供することにある。
【０００９】
【課題を解決するための手段】
本発明による携帯電話端末は、各々異なる第１及び第２の移動無線通信方式の無線信号の送受信を行う第１及び第２の無線機を含み、前記第１及び第２の無線機を切替えて通信を行う携帯電話端末であって、自端末が在圏するセルから隣接セルへの切替え時に前記第１及び第２の移動無線通信方式の無線信号の待ち受け状態で自端末が在圏するセルの制御周波数の電界レベルを測定する測定手段と、前記測定手段でレベル劣化が検出された時に当該セルのシステム制御情報の報知に使用する下りチャネルであるＢＣＣＨ（ＢｒｏａｄｃａｓｔＣｏｎｔｒｏｌＣｈａｎｎｅｌ）を受信する受信手段と、前記受信手段で受信したＢＣＣＨから前記隣接セルのＢＣＣＨ送信周波数及び前記第１の移動無線通信方式の前記ＢＣＣＨの送信タイミングと前記第２の移動無線通信方式前記ＢＣＣＨの送信タイミングとの相対値を示す相対タイミングを取得する取得手段とを備え、前記取得手段で取得した前記隣接セルのＢＣＣＨ送信周波数及び相対タイミングを基に前記第１及び第２の無線機の切替えを行っている。
【００１０】
本発明によるデュアルバンド携帯電話システムは、各々携帯電話端末が異なる第１及び第２の移動無線通信方式の無線信号の送受信を行うための複数の基地局を含む第１及び第２の移動無線通信システムからなるデュアルバンド携帯電話システムであって、
前記複数の基地局各々からの前記第１及び第２の移動無線通信システムにおけるＲＳＳＩ（ＲｅｃｅｉｖｅＳｉｇｎａｌＳｔｒｅｎｇｔｈＩｎｄｉｃａｔｉｏｎ）のレベル測定結果を基に前記第１及び第２の移動無線通信システム各々のシステム制御情報の報知に使用する下りチャネルであるＢＣＣＨ（ＢｒｏａｄｃａｓｔＣｏｎｔｒｏｌＣｈａｎｎｅｌ）の配置を決めるＢＣＣＨ制御手段を備えている。
【００１１】
本発明によるデュアルバンド切替方法は、各々異なる第１及び第２の移動無線通信方式の無線信号の送受信を行う第１及び第２の無線機を含み、前記第１及び第２の無線機を切替えて通信を行う携帯電話端末のデュアルバンド切替方法であって、自端末が在圏するセルから隣接セルへの切替え時に前記第１及び第２の移動無線通信方式の無線信号の待ち受け状態で自端末が在圏するセルの制御周波数の電界レベルを測定するステップと、その電界レベルの測定でレベル劣化が検出された時に当該セルのシステム制御情報の報知に使用する下りチャネルであるＢＣＣＨ（ＢｒｏａｄｃａｓｔＣｏｎｔｒｏｌＣｈａｎｎｅｌ）を受信するステップと、この受信したＢＣＣＨから前記隣接セルのＢＣＣＨ送信周波数及び前記第１の移動無線通信方式の前記ＢＣＣＨの送信タイミングと前記第２の移動無線通信方式前記ＢＣＣＨの送信タイミングとの相対値を示す相対タイミングを取得するステップとを備え、その取得した前記隣接セルのＢＣＣＨ送信周波数及び相対タイミングを基に前記第１及び第２の無線機の切替えを行っている。
【００１２】
本発明によるデュアルバンド切替方法のプログラムは、各々異なる第１及び第２の移動無線通信方式の無線信号の送受信を行う第１及び第２の無線機を含み、前記第１及び第２の無線機を切替えて通信を行う携帯電話端末のデュアルバンド切替方法のプログラムであって、コンピュータに、自端末が在圏するセルから隣接セルへの切替え時に前記第１及び第２の移動無線通信方式の無線信号の待ち受け状態で自端末が在圏するセルの制御周波数の電界レベルを測定する処理と、その電界レベルの測定でレベル劣化が検出された時に当該セルのシステム制御情報の報知に使用する下りチャネルであるＢＣＣＨ（ＢｒｏａｄｃａｓｔＣｏｎｔｒｏｌＣｈａｎｎｅｌ）を受信する処理と、この受信したＢＣＣＨから前記隣接セルのＢＣＣＨ送信周波数及び前記第１の移動無線通信方式の前記ＢＣＣＨの送信タイミングと前記第２の移動無線通信方式前記ＢＣＣＨの送信タイミングとの相対値を示す相対タイミングを取得する処理とを実行させ、その取得した前記隣接セルのＢＣＣＨ送信周波数及び相対タイミングを基に前記第１及び第２の無線機の切替えを行わせている。
【００１３】
すなわち、本発明のデュアルバンド携帯電話システムは、ＩＭＴ（ＩｎｔｅｒｎａｔｉｏｎａｌＭｏｂｉｌｅＴｅｌｅｃｏｍｍｕｎｉｃａｔｉｏｎｓ）無線システム及びＰＤＣ（ＰｅｒｓｏｎａｌＤｉｇｉｔａｌＣｅｌｌｕｌａｒ）無線システムの両システムの待ち受け時におけるＩＭＴ無線信号及びＰＤＣ無線信号の受信方法と、ＩＭＴ無線機及びＰＤＣ無線機に対する電源制御方法とに関し、システム制御情報の報知に使用する下りチャネルであるＢＣＣＨ（ＢｒｏａｄｃａｓｔＣｏｎｔｒｏｌＣｈａｎｎｅｌ）の送信タイミングの相対値をそれぞれＩＭＴ無線システム及びＰＤＣ無線システムのＢＳ（ＢａｓｅＳｔａｔｉｏｎ：基地局）で共有し、スキャン動作の省略を図るとともに、ＢＣＣＨの検索時間が省略可能となる。このことによって、本発明では、切替えの高速化及び処理時間の短縮が可能となる。
【００１４】
本発明の携帯電話端末は、ＩＭＴ無線システム及びＰＤＣ無線システムのＢＣＣＨの同期をとり、ＢＣＣＨの送信配置の制御を行い、ＢＣＣＨの送信タイミングを端末に送信している。
【００１５】
これによって、本発明の携帯電話端末では、自端末において各システムに切替える時間が短縮可能となり、操作性の向上を図ることが可能となる。また、本発明の携帯電話端末では、チャネルスキャン処理後のＢＣＣＨ取得のために、ＩＭＴ無線信号及びＰＤＣ無線信号の連続受信処理を省略することが可能となり、消費電流の削減が可能となる。
【００１６】
【発明の実施の形態】
次に、本発明の実施例について図面を参照して説明する。図１は本発明の一実施例によるデュアルバンド携帯電話システムの構成を示すブロック図である。図１において、本発明の一実施例によるデュアルバンド携帯電話システムはＩＭＴ（ＩｎｔｅｒｎａｔｉｏｎａｌＭｏｂｉｌｅＴｅｌｅｃｏｍｍｕｎｉｃａｔｉｏｎｓ）無線システムと、ＰＤＣ（ＰｅｒｓｏｎａｌＤｉｇｉｔａｌＣｅｌｌｕｌａｒ）無線システムとからなる。
【００１７】
ＰＤＣ無線システムはＰＤＣＭＳＣ（ＭｏｂｉｌｅＳｗｉｔｃｈｉｎｇＣｅｎｔｅｒ：移動通信交換局）１と、ＩＭＴ／ＰＤＣＢＣＣＨ（ＢｒｏａｄｃａｓｔＣｏｎｔｒｏｌＣｈａｎｎｅｌ：報知情報）制御部２と、ＰＤＣ網１００のＢＳ（ＢａｓｅＳｔａｔｉｏｎ：基地局）６１〜６３とから構成されている。
【００１８】
ＩＭＴ無線システムはＩＭＴＲＮＣ（ＲａｄｉｏＮｅｔｗｏｒｋＣｏｎｔｒｏｌｌｅｒ）３と、ＩＭＴＭＳＣ４と、ＩＭＴ／ＰＤＣＢＣＣＨ制御部２と、ＩＭＴＰＤＳＮ（ＰａｃｋｅｔＤａｔａＳｅｒｖｉｎｇＮｏｄｅ）５と、ＩＭＴ網２００のＢＳ７１〜７３とから構成されている。
【００１９】
本実施例では、ＩＭＴ／ＰＤＣＢＣＣＨ制御部２で、ＰＤＣ無線システム及びＩＭＴ無線システムそれぞれのシステムのシステム制御情報の報知に使用する下りチャネルであるＢＣＣＨの配置を決めるため、ＰＤＣ網１００のＢＳ６１〜６３及びＩＭＴ網２００のＢＳ７１〜７３各々にてＲＳＳＩ（ＲｅｃｅｉｖｅＳｉｇｎａｌＳｔｒｅｎｇｔｈＩｎｄｉｃａｔｉｏｎ）のレベル測定を行い、空きチャネル情報にしたがってＢＣＣＨの配置の最適化を行う。
【００２０】
また、ＩＭＴ／ＰＤＣＢＣＣＨ制御部２ではＰＤＣ無線システム及びＩＭＴ無線システムのシステム間のクロック同期をとる。さらに、ＩＭＴ／ＰＤＣＢＣＣＨ制御部２ではＢＣＣＨによって端末側に隣接セルのＢＣＣＨ送信周波数、相対タイミングを報知する。
【００２１】
図２は本発明の一実施例によるデュアルバンド携帯電話端末の構成を示すブロック図である。図２において、本発明の一実施例によるデュアルバンド携帯電話端末はＩＭＴ機能とＰＤＣ機能とを備えている。つまり、本発明の一実施例によるデュアルバンド携帯電話端末はＰＤＣ無線部１１と、ＩＭＴ無線部１２と、送受信タイミング制御部１３と、ＰＤＣ無線プロトコル制御部１４と、ＩＭＴ無線制御プロトコル制御部１５と、ＭＭＩ（ＭａｎＭａｃｈｉｎｅＩｎｔｅｒｆａｃｅ）制御部１６と、上記の各制御部で実行されるプログラム（コンピュータで実行可能なプログラム）を格納する記録媒体１７とから構成されている。
【００２２】
ＰＤＣ無線システムにおいては、ＰＤＣ無線プロトコル制御部１４が送受信タイミング制御部１３を介してＰＤＣ無線部１１とＩＭＴ無線部１２とを制御することによって通信を行う。ＩＭＴ無線システムについては、ＩＭＴ無線制御プロトコル制御部１５が送受信タイミング制御部１３を介してＰＤＣ無線部１１とＩＭＴ無線部１２とを制御することによって通信を行う。ＭＭＩ制御部１６についてはＩＭＴ／ＰＤＣ共通の制御となる。
【００２３】
本発明の一実施例によるデュアルバンド携帯電話端末はＩＭＴ／ＰＤＣＢＣＣＨ制御部２からのＢＣＣＨを受信し、隣接セルのＢＣＣＨに関してＲＳＳＩの監視を行い、電界レベルの高いセルを一定周期毎にモニタする。
【００２４】
図３はＢＣＣＨの配置タイミングを示す図である。図３において、ＩＭＴにおける自走クロックを１０ｍｓとし、ＰＤＣにおける自走クロックを２０ｍｓとすると、２１はＩＭＴのＢＣＣＨの送信タイミングを示し、１０ｍｓ毎にＢＣＣＨを受信することとなる。
【００２５】
一方、２２はＰＤＣのＢＣＣＨの送信タイミングを示す。ＰＤＣのＢＣＣＨの受信は１スーパフレーム毎に送信されているため、２０×ｎ（ｎはシステムによって決められる値）で決められる。ＩＭＴにおいては１０ｍｓ毎にＢＣＣＨを受信するため、１０×ｎでＰＤＣのＢＣＣＨ位置を保持する。ＰＤＣにおいては、ＩＭＴのＢＣＣＨが１０ｍｓ毎に送信されているため、タイミングの保持は必要ない。
【００２６】
送受信タイミング制御部１３は相対タイミング値として、複数チャネルのタイミングを保持し、ＰＤＣ無線システム及びＩＭＴ無線システムの切替え時に、システム各々の自走タイミングから相対時間だけずらしたタイミングに切替え、そのタイミングでＢＣＣＨの検索を行う。そのため、送受信タイミング制御部１３ではＩＭＴ無線信号及びＰＤＣ無線信号の連続受信を行わず、ＩＭＴ無線信号及びＰＤＣ無線信号の単発受信によってＢＣＣＨの受信、つまりＩＭＴのＢＣＣＨの送信タイミング２１、ＰＤＣのＢＣＣＨの送信タイミング２２でのＢＣＣＨの受信が可能となる。
【００２７】
現行のＰＤＣ無線システムにおいては、待ち受けにおけるセル移動が一度、圏外に流出すると、隣接セルのＲＳＳＩのスキャンを再度行うことで、ＢＣＣＨ検索を実施している。
【００２８】
一方、ＩＭＴ無線システムにおいては、電界の強いチャネルのＲＳＳＩのスキャンが、待ち受けにおいて一定周期で行われ、切替えにＢＣＣＨの検索を実施していることから、切替え時の処理速度は向上している。
【００２９】
しかしながら、ＰＤＣ無線システム及びＩＭＴ無線システムの両システムともに、ＢＣＣＨの送信位置については、ＢＣＣＨ検索時に、ＰＤＣ無線部１１とＩＭＴ無線部１２とを連続的に動作させ、ＢＣＣＨの検索を行っているため、切替え時の処理時間、消費電流が技術的課題となっている。
【００３０】
本実施例ではＩＭＴ／ＰＤＣＢＣＣＨ制御部２と送受信タイミング制御部１３とを現行のシステムに追加し、上記のような制御を行っているので、ＢＣＣＨの検索処理を省略することができ、切替え時の処理速度の向上と消費電流の削減とを図ることが可能となる。
【００３１】
図４及び図５は本発明の一実施例によるＰＤＣ無線システム及びＩＭＴ無線システムの切替え処理を示すフローチャートである。これら図１〜図５を参照して本発明の一実施例によるセルの切替え時におけるＰＤＣ無線システム及びＩＭＴ無線システムの切替え処理について説明する。尚、図４及び図５に示す処理は送受信タイミング制御部１３が記録媒体１７のプログラムを実行することで実現される。
【００３２】
自端末が在圏するセルから隣接セルへの切替え時、送受信タイミング制御部１３はＰＤＣ無線信号またはＩＭＴ無線信号の待ち受け状態で自端末が在圏するセルの制御周波数の電界レベルを測定し、レベル劣化を検出した場合（図４ステップＳ１）、再度、自端末が在圏するセルのＢＣＣＨの受信を行う（図４ステップＳ２）。
【００３３】
送受信タイミング制御部１３は受信ＯＫの場合（図４ステップＳ３）、隣接セルのＢＣＣＨ送信周波数及び相対タイミングの取得を行い、そのＢＣＣＨ送信周波数及び相対タイミングを基に隣接セルリストの並び替えよって最新の情報に更新する（図４ステップＳ４）。送受信タイミング制御部１３は受信がＮＧの場合、隣接セルリストの並び替えを行わない。
【００３４】
ここで、隣接セルリストとは隣接セル各々のＢＣＣＨ送信周波数及び相対タイミングを保持するリストである。また、隣接セルリストの更新は最新のＢＣＣＨの配置情報を取得し、システム間でのセル移行をスムーズにさせるためである。
【００３５】
送受信タイミング制御部１３は作成したリスト内にＩＭＴのＢＣＣＨが存在するかを確認し（図４ステップＳ５）、ＩＭＴがある場合、現在の待ち受けシステムがＰＤＣかを確認する（図４ステップＳ６）。送受信タイミング制御部１３はＰＤＣの場合、ＩＭＴの周波数帯域のチャネル定義にしたがってシンセサイザの切替えを行い、周波数の切替えを実施する（図４ステップＳ７）。また、送受信タイミング制御部１３はＰＤＣの場合、周波数が１チャネルなので、周波数の切替えを行わない。
【００３６】
送受信タイミング制御部１３は上記の周波数の切替え判断と、システム及び周波数の切替えとを実施すると、隣接セルのＢＣＣＨの受信を行うため、タイミング切替え処理にて、自走クロックを基準に受信タイミングを変更する（図４ステップＳ８）。その後、送受信タイミング制御部１３は周波数及びタイミングを切替えてＢＣＣＨの受信を行う（図４ステップＳ９）。
【００３７】
送受信タイミング制御部１３はＩＭＴのシステムがなかった場合、上記の隣接セルリストの並び替えで作成したリストに隣接セル情報があるかを確認する（図５ステップＳ１３）。送受信タイミング制御部１３は隣接セル情報があれば、待ち受け中のセルがＩＭＴかを確認し（図５ステップＳ１４）、ＩＭＴの場合、ＰＤＣへシステムを変更する。
【００３８】
このため、送受信タイミング制御部１３は無線機の切替えを実施し、システム及び周波数の変更を実施する（図５ステップＳ１５）。送受信タイミング制御部１３は待ち受けセルがＰＤＣの場合、無線機及び周波数の切替えを行わない。この後、送受信タイミング制御部１３はタイミング切替え処理を実施し（図５ステップＳ１６）、ＢＣＣＨの受信を実施する（図４ステップＳ９）。
【００３９】
送受信タイミング制御部１３はＢＣＣＨ受信動作を実施後、受信ＯＫの場合（図４ステップＳ１０）、待ち受け処理に移行する（図４ステップＳ１１）。送受信タイミング制御部１３は受信ＮＧの場合（図４ステップＳ１０）、次のチャネルを選択し（図４ステップＳ１２）、ステップＳ５に戻って上記の処理を繰り返し実施する。
【００４０】
送受信タイミング制御部１３はステップＳ１３において隣接セル情報がなくなった場合、圏外処理へ移行する（図４ステップＳ１７）。ステップＳ１１の待ち受け処理は、ＲＣＲ（電波システム開発センタ）、３ＧＰＰ（３ｒｄＧｅｎｅｒａｔｉｏｎＰａｒｔｎｅｒｓｈｉｐＰｒｏｊｅｃｔ）ですでに規定されている手順にしたがって実施される。
【００４１】
ステップＳ１７の圏外移行処理においては、ＩＭＴ／ＰＤＣで規定されており、周波数を交互にＲＳＳＩスキャンを行ってＢＣＣＨの検索を行うために、連続的に受信動作を行う。
【００４２】
このように、本実施例では、ＩＭＴ、ＰＤＣのＢＣＣＨの同期をとり、ＢＣＣＨの送信配置の制御を行い、ＢＣＣＨの送信タイミングを端末に通知することによって、端末が各システムに切替える時間を短縮することができ、操作性の向上を図ることができる。また、本実施例では、チャネルスキャン処理後のＢＣＣＨ取得のために連続受信処理を省略することができ、消費電流を削減することができる。
【００４３】
さらに、本実施例では、ＢＣＣＨの送信タイミングの相対値をそれぞれのＢＳ６１〜６３，７１〜７３で共有し、スキャンの省略に追加して、ＢＣＣＨの検索時間を省略することができる。これによって、本実施例では、各システムの切替えの高速化及び処理時間の短縮を図ることができる。
【００４４】
【発明の効果】
以上説明したように本発明は、ＰＤＣ無線信号及びＩＭＴ無線信号の送受信を行うＰＤＣ無線機及びＩＭＴ無線機を含み、ＰＤＣ無線機及びＩＭＴ無線機を切替えて通信を行う携帯電話端末において、自端末が在圏するセルから隣接セルへの切替え時にＰＤＣ無線信号及びＩＭＴ無線信号の待ち受け状態で自端末が在圏するセルの制御周波数の電界レベルを測定し、その電界レベルの測定でレベル劣化が検出された時に当該セルのシステム制御情報の報知に使用する下りチャネルであるＢＣＣＨを受信し、この受信したＢＣＣＨから隣接セルのＢＣＣＨ送信周波数及びＰＤＣ無線システムのＢＣＣＨの送信タイミングとＩＭＴ無線システムのＢＣＣＨの送信タイミングとの相対値を示す相対タイミングを取得し、その取得した隣接セルのＢＣＣＨ送信周波数及び相対タイミングを基にＰＤＣ無線機及びＩＭＴ無線機の切替えを行うことによって、各システムに切替える時間の短縮と操作性の向上とを図ることができ、消費電流を削減することができるという効果が得られる。
【図面の簡単な説明】
【図１】本発明の一実施例によるデュアルバンド携帯電話システムの構成を示すブロック図である。
【図２】本発明の一実施例によるデュアルバンド携帯電話端末の構成を示すブロック図である。
【図３】ＢＣＣＨの配置タイミングを示す図である。
【図４】本発明の一実施例によるＰＤＣ無線システム及びＩＭＴ無線システムの切替え処理を示すフローチャートである。
【図５】本発明の一実施例によるＰＤＣ無線システム及びＩＭＴ無線システムの切替え処理を示すフローチャートである。
【符号の説明】
１ＰＤＣＭＳＣ１
２ＩＭＴ／ＰＤＣＢＣＣＨ制御部
３ＩＭＴＲＮＣ
４ＩＭＴＭＳＣ
５ＩＭＴＰＤＳＮ
１１ＰＤＣ無線部
１２ＩＭＴ無線部
１３送受信タイミング制御部
１４ＰＤＣ無線プロトコル制御部
１５ＩＭＴ無線制御プロトコル制御部
１６ＭＭＩ制御部
１７記録媒体
６１〜６３，
７１〜７３ＢＳ
１００ＰＤＣ網
２００ＩＭＴ網[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mobile phone terminal, a dual-band mobile phone system, and a dual-band switching method used for the same, and more particularly, to an IMT (International Mobile Telecommunications) function as a third-generation mobile phone system and a PDC (Personal) as an existing mobile phone system. The present invention relates to a mobile phone terminal having both a digital cellular (Digital Cellular) function.
[0002]
[Prior art]
A terminal having both an IMT function as a third-generation mobile phone system and a PDC function as an existing mobile phone system needs to have a wireless unit due to differences in wireless systems (for example, see Patent Document 1). 3).
[0003]
In the development of a dual band mobile phone terminal having an IMT function and a PDC function, the reduction of the IMT switching time is a major factor for the product's power. When the IMT radio signal and the PDC radio signal are simultaneously received, the It is necessary to operate the PDC radio at the same time, which affects the current consumption.
[0004]
Further, as a switching method of this kind of different wireless systems, two system control frequencies are stored, and when moving out of a service area, a cell search operation is performed based on the control frequency previously stored in a memory. There is a method of performing scanning of all control frequencies when there is no frequency stored in the memory in advance (for example, see Patent Document 4).
[0005]
Thus, in the above-described wireless system switching method, if control channel information is included in the list, the scanning operation can be omitted, and current consumption can be reduced and switching can be speeded up.
[0006]
[Patent Document 1]
JP-A-63-203025 (pages 8 to 12, FIG. 1)
[Patent Document 2]
JP-A-05-102923 (pages 2 to 4, FIG. 2)
[Patent Document 3]
JP-A-09-051321 (pages 3 to 6, FIG. 1)
[Patent Document 4]
JP-A-11-298964 (pages 5 and 6, FIG. 1)
[0007]
[Problems to be solved by the invention]
In the above-described conventional mobile phone system, when switching between the IMT wireless system and the PDC wireless system, if the IMT wireless signal and the PDC wireless signal are simultaneously waited, it is necessary to operate the IMT wireless device and the PDC wireless device at the same time. Therefore, there is a problem that the current consumption increases and the standby time becomes short. In a mobile phone terminal, an increase in current consumption leads to a decrease in product power, which is a major problem.
[0008]
Therefore, an object of the present invention is to solve the above-mentioned problems, to shorten the time for switching between the IMT wireless system and the PDC wireless system, to improve the operability, and to reduce the current consumption. An object of the present invention is to provide a terminal, a dual-band mobile phone system, and a dual-band switching method used for them.
[0009]
[Means for Solving the Problems]
A mobile phone terminal according to the present invention includes first and second wireless devices for transmitting and receiving wireless signals of different first and second mobile wireless communication systems, and switches between the first and second wireless devices. A mobile phone terminal that performs communication, wherein a cell in which the terminal is located in a standby state of the wireless signal of the first and second mobile wireless communication systems when switching from a cell in which the terminal is located to an adjacent cell; Measuring means for measuring the electric field level of the control frequency; and receiving means for receiving a BCCH (Broadcast Control Channel) which is a downlink channel used for reporting system control information of the cell when the level deterioration is detected by the measuring means; The BCCH transmission frequency of the adjacent cell from the BCCH received by the receiving means and the transmission timing of the BCCH of the first mobile radio communication system; Acquiring means for acquiring a relative timing indicating a relative value with respect to the BCCH transmission timing of the second mobile radio communication system, wherein the BCCH transmission frequency and relative timing of the adjacent cell acquired by the acquiring means The first and second wireless devices are switched.
[0010]
A dual-band mobile phone system according to the present invention includes first and second mobile radio communications each including a plurality of base stations for transmitting and receiving radio signals of different first and second mobile radio communication schemes. A dual-band mobile phone system comprising:
System control information of each of the first and second mobile radio communication systems based on a result of RSSI (Receive Signal Strength Indication) level measurement in the first and second mobile radio communication systems from each of the plurality of base stations. Is provided with a BCCH (Broadcast Control Channel), which is a downlink channel used for broadcasting of the broadcast.
[0011]
A dual band switching method according to the present invention includes first and second wireless devices for transmitting and receiving wireless signals of different first and second mobile wireless communication systems, respectively, and switching between the first and second wireless devices. A dual-band switching method for a mobile phone terminal that performs communication with the mobile terminal in a standby state of the wireless signals of the first and second mobile wireless communication systems at the time of switching from a cell in which the terminal is located to an adjacent cell. Measuring the electric field level of the control frequency of the cell in which the cell is located, and a broadcast control channel (BCCH), which is a downlink channel used to broadcast system control information of the cell when a level deterioration is detected in the measurement of the electric field level. ), And a BCCH transmission frequency of the adjacent cell and the first mobile radio communication method from the received BCCH. Obtaining a relative timing indicating a relative value between the transmission timing of the BCCH and the transmission timing of the BCCH of the second mobile radio communication system, and obtaining the BCCH transmission frequency and the relative timing of the obtained adjacent cell. The switching between the first and second wireless devices is performed based on this.
[0012]
A program of a dual band switching method according to the present invention includes first and second wireless devices for transmitting and receiving wireless signals of different first and second mobile wireless communication systems, and the first and second wireless devices. A program for a dual-band switching method for a mobile phone terminal that performs communication by switching between the first and second mobile wireless communication systems when switching from a cell in which the own terminal is located to an adjacent cell. A process of measuring an electric field level of a control frequency of a cell in which the terminal is located in a signal waiting state, and a downlink channel used for reporting system control information of the cell when a level deterioration is detected in the measurement of the electric field level Receiving a BCCH (Broadcast Control Channel), and transmitting the BCCH transmission frequency of the adjacent cell from the received BCCH. And performing a process of acquiring a relative timing indicating a number and a relative value between the BCCH transmission timing of the first mobile radio communication system and the BCCH transmission timing of the second mobile radio communication system. The first and second wireless devices are switched based on the BCCH transmission frequency and the relative timing of the adjacent cell.
[0013]
That is, the dual-band mobile phone system according to the present invention provides a method for receiving an IMT wireless signal and a PDC wireless signal during standby in both an IMT (International Mobile Telecommunications) wireless system and a PDC (Personal Digital Cellular) wireless system. And a power control method for a PDC wireless device, a relative value of a transmission timing of a BCCH (Broadcast Control Channel), which is a downlink channel used for reporting system control information, is set to a BS (Base Station) of an IMT wireless system and a PDC wireless system, respectively. : Base station), the scanning operation can be omitted, and the BCCH search time can be omitted. As a result, in the present invention, it is possible to speed up the switching and to shorten the processing time.
[0014]
The mobile phone terminal of the present invention synchronizes the BCCH of the IMT wireless system and the PDC wireless system, controls the transmission arrangement of the BCCH, and transmits the transmission timing of the BCCH to the terminal.
[0015]
As a result, in the mobile phone terminal of the present invention, the time for switching to each system in the own terminal can be reduced, and the operability can be improved. Further, in the mobile phone terminal of the present invention, it is possible to omit the continuous reception processing of the IMT wireless signal and the PDC wireless signal to obtain the BCCH after the channel scan processing, and it is possible to reduce the current consumption.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a dual band mobile phone system according to one embodiment of the present invention. Referring to FIG. 1, a dual-band mobile phone system according to an embodiment of the present invention includes an IMT (International Mobile Telecommunications) wireless system and a PDC (Personal Digital Cellular) wireless system.
[0017]
The PDC wireless system includes a PDC MSC (Mobile Switching Center) 1, an IMT / PDC BCCH (Broadcast Control Channel: broadcast information) control unit 2, and a BS (Base Station: base station) 61 to 61 of the PDC network 100. 63.
[0018]
The IMT wireless system includes an IMT RNC (Radio Network Controller) 3, an IMT MSC 4, an IMT / PDC BCCH control unit 2, an IMT PDSN (Packet Data Serving Node) 5, and BSs 71 to 73 of the IMT network 200. I have.
[0019]
In the present embodiment, the IMT / PDC BCCH control unit 2 determines the arrangement of the BCCH, which is a downlink channel used to broadcast system control information of each of the PDC wireless system and the IMT wireless system. The BS 63 and the BS 71 to 73 of the IMT network 200 each measure the level of RSSI (Receive Signal Strength Indication) and optimize the arrangement of the BCCH according to the available channel information.
[0020]
The IMT / PDC BCCH control unit 2 synchronizes clocks between the PDC wireless system and the IMT wireless system. Further, the IMT / PDC BCCH control unit 2 notifies the terminal side of the BCCH transmission frequency and the relative timing of the adjacent cell by using the BCCH.
[0021]
FIG. 2 is a block diagram showing a configuration of a dual band mobile phone terminal according to one embodiment of the present invention. In FIG. 2, the dual-band mobile phone terminal according to one embodiment of the present invention has an IMT function and a PDC function. That is, the dual-band mobile phone terminal according to one embodiment of the present invention includes a PDC radio unit 11, an IMT radio unit 12, a transmission / reception timing control unit 13, a PDC radio protocol control unit 14, and an IMT radio control protocol control unit 15. , An MMI (Man Machine Interface) control unit 16 and a recording medium 17 for storing a program (a computer executable program) executed by each of the above control units.
[0022]
In the PDC wireless system, the PDC wireless protocol control unit 14 performs communication by controlling the PDC wireless unit 11 and the IMT wireless unit 12 via the transmission / reception timing control unit 13. In the IMT wireless system, the IMT wireless control protocol control unit 15 performs communication by controlling the PDC wireless unit 11 and the IMT wireless unit 12 via the transmission / reception timing control unit 13. The MMI control unit 16 performs common control for IMT / PDC.
[0023]
The dual-band mobile phone terminal according to one embodiment of the present invention receives the BCCH from the IMT / PDC BCCH control unit 2, monitors the RSSI with respect to the BCCH of an adjacent cell, and monitors a cell having a high electric field level at regular intervals. .
[0024]
FIG. 3 is a diagram showing the arrangement timing of the BCCH. In FIG. 3, assuming that the free-running clock in the IMT is 10 ms and the free-running clock in the PDC is 20 ms, 21 indicates the transmission timing of the BCCH of the IMT, and the BCCH is received every 10 ms.
[0025]
On the other hand, 22 indicates the transmission timing of the BCCH of the PDC. Since the reception of the BCCH of the PDC is transmitted every superframe, it is determined by 20 × n (n is a value determined by the system). In the IMT, the BCCH position of the PDC is held at 10 × n in order to receive the BCCH every 10 ms. In the PDC, since the BCCH of the IMT is transmitted every 10 ms, it is not necessary to hold the timing.
[0026]
The transmission / reception timing control unit 13 holds the timings of a plurality of channels as relative timing values, and when switching between the PDC wireless system and the IMT wireless system, switches to a timing shifted from the self-running timing of each system by a relative time. Perform a search. Therefore, the transmission / reception timing control unit 13 does not continuously receive the IMT wireless signal and the PDC wireless signal, but receives the BCCH by single-shot reception of the IMT wireless signal and the PDC wireless signal, that is, the transmission timing 21 of the IMT BCCH, the PDC BCCH. The BCCH can be received at the transmission timing 22.
[0027]
In the current PDC wireless system, when the cell movement in the standby mode flows out of the service area, the BCCH search is performed by re-scanning the RSSI of the adjacent cell.
[0028]
On the other hand, in the IMT wireless system, the scanning of the RSSI of the channel having a strong electric field is performed at a constant period in the standby mode, and the search of the BCCH is performed for the switching. Therefore, the processing speed at the time of the switching is improved.
[0029]
However, in both the PDC wireless system and the IMT wireless system, the BCDC transmission position is such that the PDC wireless unit 11 and the IMT wireless unit 12 are continuously operated to search for the BCCH during the BCCH search. In addition, processing time and current consumption at the time of switching are technical issues.
[0030]
In the present embodiment, the IMT / PDC BCCH control unit 2 and the transmission / reception timing control unit 13 are added to the current system and the above-described control is performed, so that the BCCH search process can be omitted, and It is possible to improve the processing speed and reduce the current consumption.
[0031]
4 and 5 are flowcharts showing a switching process between the PDC wireless system and the IMT wireless system according to one embodiment of the present invention. The switching process of the PDC wireless system and the IMT wireless system at the time of cell switching according to one embodiment of the present invention will be described with reference to FIGS. 4 and 5 are realized by the transmission / reception timing control unit 13 executing the program on the recording medium 17.
[0032]
When switching from the cell in which the terminal is located to the neighboring cell, the transmission / reception timing control unit 13 measures the electric field level of the control frequency of the cell in which the terminal is located in a standby state of the PDC radio signal or the IMT radio signal, and When the deterioration is detected (step S1 in FIG. 4), the mobile station again receives the BCCH of the cell in which the terminal is located (step S2 in FIG. 4).
[0033]
If the reception is OK (step S3 in FIG. 4), the transmission / reception timing control unit 13 acquires the BCCH transmission frequency and the relative timing of the adjacent cell, and rearranges the adjacent cell list based on the BCCH transmission frequency and the relative timing to update the latest. The information is updated (step S4 in FIG. 4). When reception is NG, the transmission / reception timing control unit 13 does not rearrange the adjacent cell list.
[0034]
Here, the neighbor cell list is a list that holds the BCCH transmission frequency and the relative timing of each neighbor cell. The update of the neighbor cell list is for obtaining the latest BCCH allocation information and for smooth cell transfer between systems.
[0035]
The transmission / reception timing control unit 13 checks whether the BCCH of the IMT exists in the created list (step S5 in FIG. 4), and when the IMT exists, checks whether the current standby system is the PDC (step S6 in FIG. 4). In the case of PDC, the transmission / reception timing control unit 13 switches the synthesizer according to the channel definition of the frequency band of the IMT, and switches the frequency (step S7 in FIG. 4). In the case of PDC, the transmission / reception timing control unit 13 does not perform frequency switching because the frequency is one channel.
[0036]
The transmission / reception timing control unit 13 changes the reception timing based on the free-running clock in the timing switching process in order to receive the BCCH of the adjacent cell when the above-described frequency switching determination and the system and frequency switching are performed. (Step S8 in FIG. 4). Thereafter, the transmission / reception timing control unit 13 switches the frequency and the timing to receive the BCCH (Step S9 in FIG. 4).
[0037]
When there is no IMT system, the transmission / reception timing control unit 13 checks whether the list created by rearranging the neighboring cell list includes neighboring cell information (step S13 in FIG. 5). If there is neighboring cell information, the transmission / reception timing control unit 13 checks whether the waiting cell is the IMT (step S14 in FIG. 5), and in the case of the IMT, changes the system to the PDC.
[0038]
For this reason, the transmission / reception timing control unit 13 switches the wireless device, and changes the system and the frequency (step S15 in FIG. 5). When the standby cell is a PDC, the transmission / reception timing control unit 13 does not switch the radio and the frequency. Thereafter, the transmission / reception timing control unit 13 performs a timing switching process (Step S16 in FIG. 5), and receives the BCCH (Step S9 in FIG. 4).
[0039]
After performing the BCCH reception operation, if the reception is OK (step S10 in FIG. 4), the transmission / reception timing control unit 13 shifts to a standby process (step S11 in FIG. 4). In the case of reception NG (step S10 in FIG. 4), the transmission / reception timing control unit 13 selects the next channel (step S12 in FIG. 4), returns to step S5, and repeats the above processing.
[0040]
When there is no adjacent cell information in step S13, the transmission / reception timing control unit 13 shifts to out-of-service processing (step S17 in FIG. 4). The standby process in step S11 is performed according to a procedure already defined in RCR (Radio System Development Center) and 3GPP (3rd Generation Partnership Project).
[0041]
In the out-of-service transfer process in step S17, the reception operation is continuously performed in order to perform the RSSI scan alternately on the frequency and search for the BCCH, which is defined by IMT / PDC.
[0042]
As described above, in this embodiment, the BCCH of the IMT and the PDC is synchronized, the transmission arrangement of the BCCH is controlled, and the transmission timing of the BCCH is notified to the terminal, so that the time required for the terminal to switch to each system is reduced. Operability can be improved. Further, in the present embodiment, the continuous reception process can be omitted for obtaining the BCCH after the channel scan process, and the current consumption can be reduced.
[0043]
Further, in this embodiment, the relative values of the BCCH transmission timings are shared by the BSs 61 to 63 and 71 to 73, and the BCCH search time can be omitted in addition to the omission of scanning. As a result, in this embodiment, it is possible to speed up the switching of each system and shorten the processing time.
[0044]
【The invention's effect】
As described above, the present invention relates to a mobile phone terminal that includes a PDC wireless device and an IMT wireless device that transmit and receive a PDC wireless signal and an IMT wireless signal, and performs communication by switching between the PDC wireless device and the IMT wireless device. Measures the electric field level of the control frequency of the cell in which the terminal is located in a standby state of the PDC radio signal and the IMT radio signal when switching from the cell where the cell is located to the adjacent cell, and detects the level degradation by measuring the electric field level When it is received, the base station receives a BCCH, which is a downlink channel used for broadcasting system control information of the cell, and uses the received BCCH to transmit the BCCH transmission frequency of the adjacent cell, the transmission timing of the BCCH of the PDC radio system, and the BCCH of the IMT radio system. The relative timing indicating the relative value to the transmission timing is acquired, and the acquired BC of the adjacent cell is acquired. By switching the PDC radio and the IMT radio based on the H transmission frequency and the relative timing, it is possible to shorten the time for switching to each system and improve the operability, and reduce the current consumption. The effect is obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a dual band mobile phone system according to one embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a dual band mobile phone terminal according to one embodiment of the present invention.
FIG. 3 is a diagram showing BCCH allocation timing.
FIG. 4 is a flowchart illustrating a switching process between a PDC wireless system and an IMT wireless system according to an embodiment of the present invention.
FIG. 5 is a flowchart illustrating a switching process between a PDC wireless system and an IMT wireless system according to an embodiment of the present invention.
[Explanation of symbols]
1 PDC MSC1
2 IMT / PDC BCCH control unit 3 IMT RNC
4 IMT MSC
5 IMT PDSN
Reference Signs List 11 PDC radio section 12 IMT radio section 13 Transmission / reception timing control section 14 PDC radio protocol control section 15 IMT radio control protocol control section 16 MMI control section 17 Recording media 61 to 63,
71-73 BS
100 PDC network 200 IMT network

Claims

A mobile telephone terminal including first and second wireless devices for transmitting and receiving wireless signals of different first and second mobile wireless communication systems, and performing communication by switching the first and second wireless devices. And measuring the electric field level of the control frequency of the cell in which the terminal is located in a standby state for the radio signals of the first and second mobile radio communication systems when switching from the cell in which the terminal is located to an adjacent cell. Measuring means, receiving means for receiving a BCCH (Broadcast Control Channel) which is a downlink channel used for reporting system control information of the cell when level deterioration is detected by the measuring means, and BCCH received by the receiving means And the BCCH transmission frequency of the adjacent cell, the BCCH transmission timing of the first mobile radio communication system, and the second mobile radio communication system Acquisition means for acquiring a relative timing indicating a relative value to the BCCH transmission timing of the first and second cells based on the BCCH transmission frequency and the relative timing of the adjacent cell acquired by the acquisition means. A mobile phone terminal for switching between wireless devices.

An adjacent cell list holding the BCCH transmission frequency and relative timing of each of the adjacent cells is included, and the latest cell list is rearranged by rearranging the adjacent cell list based on the BCCH transmission frequency and relative timing of the adjacent cell acquired by the acquisition unit. The mobile phone terminal according to claim 1, wherein the information is updated to information.

The mobile phone terminal according to claim 2, wherein the search for the BCCH is performed based on the contents of the neighbor cell list.

4. The mobile phone terminal according to claim 2, wherein a power-on time for each of the first and second wireless devices is determined based on the contents of the neighboring cell list.

6. The method according to claim 1, wherein the first mobile wireless communication system is IMT (International Mobile Telecommunications), and the second mobile wireless communication system is PDC (Personal Digital Cellular). The described mobile phone terminal.

A dual-band mobile telephone system including first and second mobile radio communication systems each including a plurality of base stations for transmitting and receiving radio signals of different first and second mobile radio communication systems, each of the mobile telephone terminals. hand,
System control information of each of the first and second mobile radio communication systems based on a result of RSSI (Receive Signal Strength Indication) level measurement in the first and second mobile radio communication systems from each of the plurality of base stations. And a BCCH (Broadcast Control Channel), which is a downlink channel used for broadcast of the broadcast, is provided.

The BCCH control means synchronizes clocks between the first and second mobile radio communication systems, and transmits the BCCH transmission timing of the first mobile radio communication system and the second mobile radio communication system. 7. The dual-band mobile phone system according to claim 6, wherein a relative timing indicating a relative value to the BCCH transmission timing and a BCCH transmission frequency are reported to the mobile phone terminal.

8. The dual-band mobile phone system according to claim 6, wherein the BCCH control unit optimizes the arrangement of the BCCH according to available channel information based on the RSSI level measurement result.

9. The dual band mobile phone system according to claim 6, wherein the plurality of base stations share a relative value of the transmission timing of the BCCH.

The said 1st mobile radio | wireless communication system is IMT (International Mobile Telecommunications), and the said 2nd mobile radio | wireless communication system is PDC (Personal Digital Cellular), The Claim 1 characterized by the above-mentioned. The dual band mobile phone system as described.

A dual mobile telephone terminal including first and second wireless devices for transmitting and receiving wireless signals of different first and second mobile wireless communication systems, and performing communication by switching the first and second wireless devices. A band switching method, wherein a control frequency of a cell in which a terminal is located in a standby state of a radio signal of the first and second mobile radio communication systems when switching from a cell in which the terminal is located to an adjacent cell is described. Measuring the electric field level, receiving a broadcast control channel (BCCH), which is a downlink channel used to broadcast system control information of the cell when a level deterioration is detected in the measurement of the electric field level, and And the BCCH transmission frequency of the adjacent cell and the BCCH transmission timing of the first mobile radio communication system, Obtaining a relative timing indicating a relative value with respect to the BCCH transmission timing in the second mobile radio communication system. The first and second mobile radio communication systems use the first and second BCCH transmission frequencies and relative timings based on the obtained BCCH transmission frequency and relative timing. 2. A dual band switching method, comprising: switching between two wireless devices.

The latest information is updated by rearranging an adjacent cell list holding the BCCH transmission frequency and the relative timing of each of the adjacent cells based on the acquired BCCH transmission frequency and the relative timing of the adjacent cell. Item 12. The dual band switching method according to Item 11.

13. The mobile phone terminal according to claim 12, wherein the search for the BCCH is performed based on the contents of the neighbor cell list.

14. The dual band switching method according to claim 12, wherein a power-on time for each of the first and second wireless devices is determined based on contents of the neighboring cell list.

15. The mobile communication system according to claim 11, wherein the first mobile wireless communication system is an IMT (International Mobile Telecommunications), and the second mobile wireless communication system is a PDC (Personal Digital Cellular). The described dual band switching method.

A dual mobile telephone terminal including first and second wireless devices for transmitting and receiving wireless signals of different first and second mobile wireless communication systems, and performing communication by switching the first and second wireless devices. A program for a band switching method, wherein the terminal is located in a computer in a standby state of the radio signals of the first and second mobile radio communication systems when switching from a cell in which the terminal is located to an adjacent cell. A process of measuring an electric field level of a control frequency of a cell, and when a level deterioration is detected in the measurement of the electric field level, a BCCH (Broadcast Control Channel) which is a downlink channel used for broadcasting system control information of the cell is received. Processing and, from the received BCCH, the BCCH transmission frequency of the adjacent cell and the BCCH of the first mobile radio communication system. A process of acquiring a relative timing indicating a relative value between the transmission timing and the BCCH transmission timing of the second mobile radio communication system, and performing the process based on the acquired BCCH transmission frequency and relative timing of the adjacent cell. A program for causing the first and second wireless devices to be switched.