JP3730955B2

JP3730955B2 - Communication apparatus, mobile communication system, and interference prediction method

Info

Publication number: JP3730955B2
Application number: JP2002350505A
Authority: JP
Inventors: 徹直井
Original assignee: NEC Communication Systems Ltd
Current assignee: NEC Communication Systems Ltd
Priority date: 2002-12-02
Filing date: 2002-12-02
Publication date: 2006-01-05
Anticipated expiration: 2022-12-02
Also published as: JP2004186924A

Description

【０００１】
【発明の属する技術分野】
本発明は、通信装置、移動体通信システム及び干渉予測方法に関し、特に、情報を送受信するための信号よりも低い周波数の電磁波を用いて、情報を送受信するための信号を伝搬する電磁波の干渉の発生を予測する通信装置、移動体通信システム及び干渉予測方法に関する。
【０００２】
【従来の技術】
８００ＭＨｚ〜２ＧＨｚ程度の周波数帯の電磁波は、遠くまで届く上に建造物等の陰にもある程度回り込んで伝わる性質があるため、無線通信に広く適用されている。しかし、この周波数帯域の電波は、建造物等で反射されやすい性質も併せ持っている。
【０００３】
送信された電波が建造物等で反射されると、送信側の端末から受信側の端末に至る電波の通路（伝搬経路）が複数形成される「マルチパス（Ｍｕｌｔｉ−Ｐａｔｈ）」が発生する。
マルチパスが発生すると、受信側の端末には複数の方向から目的の電波が到達することになるが、各経路を介して受信側の端末に到達した電波がそれぞれ干渉を起こしてしまう。
【０００４】
建造物等で反射されて受信側の端末に到達した電波（間接波）は、直接到達した電波（直接波）に比べて伝搬距離が長くなるため時間的に遅れて到達することになる。例えば、市街地等における直接波と間接波との到達時間の差は数十μｓ程度、室内における無線ＬＡＮ等の場合は、数十ｎｓ程度となる。
【０００５】
電波の到達時間に差が生じると受信側の端末のアンテナには位相が異なる信号が到達することになる。このため、受信側の端末が実際に受信する信号は、希望波（例えば、直接波）と干渉波（例えば、間接波）とを合成したものとなる。このとき、干渉波は希望波に対する干渉成分として作用し、位相が合致したときは信号が互いに強めあい、位相が反対になると信号が互いに弱めあうことになる。
【０００６】
移動体通信の場合は、送信側および受信側の端末のどちらか一方あるいは両方が移動するため、ドップラーシフトの影響により直接波と間接波とで周波数が異なってしまう。さらに、間接波が発生する原因になる建造物等と各端末との距離が変動するため、直接波と間接波とで受信タイミングも異なってしまう。
よって、マルチパスが発生した状態においては希望波と干渉波との位相の関係が時々刻々と変化し、希望波と干渉波との合成信号の振幅が大幅に変化する「フェージング」現象が発生することとなる。フェージングが発生すると、ディジタル通信系では希望波干渉波比（ＳＩＲ）が極端に低下して、データ誤りが著しく増加してしまう。
【０００７】
受信側の端末が直接波を受信できる「見通し内通信」の場合は、直接波を安定した定常波として受信できるため受信電界の強度が落ち込むことは少ない。一方、直接波を受信できない「見通し外通信」の場合は、同じ程度の強さの反射波や回折波を多数受信することになり、受信電界の強度が激しく変動することになりマルチパスによる干渉の影響は顕著になる。
【０００８】
マルチパスによる干渉の影響を低減する従来技術として、特許文献１に開示される「干渉キャンセラにおける伝搬路推定方法及び干渉除去装置」がある。
特許文献１に記載の発明は、パイロットシンボルを用いてそれぞれのパスの伝搬路の特性を推定することにより、受信データから伝搬路の影響を除去するものである。
【０００９】
【特許文献１】
特開２０００−８３０１１号公報
【００１０】
【発明が解決しようとする課題】
干渉の影響を低減するためには、特許文献１に記載された発明のように干渉が発生した信号を受信してその影響を除去するのではなく、その影響による受信電界の変化を予め予測し、何らかの対策を講じることが好ましい。
しかし、移動体通信では各端末が任意の方向へ移動できるうえに、間接波の発生する原因となる建造物等が存在する方向や各端末から建造物等までの距離も一定ではないため、干渉の発生を予測することは困難であった。
【００１１】
本発明は、かかる問題に鑑みてなされたものであり、干渉の影響を事前に察知できる通信装置、移動体通信システム及び干渉予測方法を提供することを目的とする。
【００１２】
【課題を解決するための手段】
上記目的を達成するため、本発明は、第１の態様として、無線信号を用いて相手側の装置との間で情報を送受信する通信装置であって、周期的に変化するガイド信号を生成する手段と、ガイド信号を無線信号よりも低い周波数で、該無線信号と共に相手側の装置へ送信する手段と、任意の時点で相手側の装置から発せられたガイド信号を所定の時間幅をもって受信する手段と、所定の時間幅をもって受信したガイド信号の信号強度の変化を取得する手段と、ガイド信号の所定の時間幅における信号強度の変化を示すデータを、一定期間分のガイド信号について保存する手段と、一定期間分のガイド信号の信号強度の変化に基づいて、相手側の装置から受信する無線信号の信号強度の変化を予測する手段とを有することを特徴とする通信装置を提供するものである。
【００１３】
また、上記目的を達成するため、本発明は、第２の態様として、送信装置から受信装置へ無線信号を用いて情報を送信する移動体通信システムであって、送信装置は、周期的に変化するガイド信号を生成する手段と、ガイド信号を無線信号よりも低い周波数で、該無線信号と共に受信装置へ送信する手段とを有し、受信装置は、任意の時点で送信装置から発せられたガイド信号を所定の時間幅をもって受信する手段と、所定の時間幅をもって受信したガイド信号の信号強度の変化を取得する手段と、ガイド信号の所定の時間幅における信号強度の変化を示すデータを、一定期間分のガイド信号について保存する手段と、一定期間分のガイド信号の信号強度の変化に基づいて、送信装置から受信する無線信号の信号強度の変化を予測する手段とを有することを特徴とする移動体通信システムを提供するものである。
【００１４】
また、上記目的を達成するため、本発明は、第３の態様として、第１の装置と第２の装置との間で無線信号を用いて情報を送受信する移動体通信システムであって、第１の装置及び第２の装置のそれぞれは、周期的に変化するガイド信号を生成する手段と、ガイド信号を無線信号よりも低い周波数で、該無線信号と共に相手側の装置へ送信する手段と、任意の時点で相手側の装置から発せられたガイド信号を所定の時間幅をもって受信する手段と、所定の時間幅をもって受信したガイド信号の信号強度の変化を取得する手段と、ガイド信号の所定の時間幅における信号強度の変化を示すデータを、一定期間分のガイド信号について保存する手段と、一定期間分のガイド信号の信号強度の変化に基づいて、相手側の装置から受信する無線信号の信号強度の変化を予測する手段とを有することを特徴とする移動体通信システムを提供するものである。
【００１５】
また、上記目的を達成するため、本発明は、第４の態様として、基地局と少なくとも一つの通信装置との間で無線信号を用いて情報を送受信する移動体通信システムであって、基地局は、周期的に変化する下りガイド信号を生成する手段と、下りガイド信号を無線信号よりも低い周波数で、該無線信号と共に通信装置のそれぞれへ送信する手段と、任意の時点で通信装置のそれぞれから発せられた上りガイド信号を所定の時間幅をもって受信する手段と、所定の時間幅をもって受信した上りガイド信号の信号強度の変化を取得する手段と、上りガイド信号の所定の時間幅における信号強度の変化を示すデータを、一定期間分の上りガイド信号について保存する手段と、一定期間分の上りガイド信号の信号強度の変化に基づいて、通信装置のそれぞれから受信する無線信号の信号強度の変化を予測する手段とを各通信装置ごとに有し、通信装置のそれぞれは、周期的に変化する上りガイド信号を生成する手段と、上りガイド信号を無線信号よりも低い周波数で、該無線信号と共に基地局へ送信する手段と、任意の時点で基地局から発せられた下りガイド信号を所定の時間幅をもって受信する手段と、所定の時間幅をもって受信した下りガイド信号の信号強度の変化を取得する手段と、下りガイド信号の所定の時間幅における信号強度の変化を示すデータを、一定期間分の下りガイド信号について保存する手段と、一定期間分の下りガイド信号の信号強度の変化に基づいて、基地局から受信する無線信号の信号強度の変化を予測する手段とを有することを特徴とする移動体通信システムを提供するものである。
【００１６】
また、上記目的を達成するため、本発明は、第５の態様として、送信装置から受信装置へ無線信号を用いて情報を送信する移動体通信システムにおける干渉予測方法であって、送信装置が、周期的に変化するガイド信号を生成し、ガイド信号を無線信号よりも低い周波数で、該無線信号と共に送信装置から受信装置へ送信し、受信装置が、任意の時点で送信装置から発せられたガイド信号を所定の時間幅をもって受信し、受信装置が、所定の時間幅をもって受信したガイド信号の信号強度の変化を取得し、受信装置が、ガイド信号の所定の時間幅における信号強度の変化を示すデータを、一定期間分のガイド信号について保存し、一定期間分のガイド信号の信号強度の変化に基づいて、無線信号の信号強度の変化を予測することを特徴とする干渉予測方法を提供するものである。
【００１７】
また、上記目的を達成するため、本発明は、第６の態様として、第１の装置と第２の装置との間で無線信号を用いて情報を送受信する移動体通信システムにおける干渉予測方法であって、第１及び第２の装置のうち送信側となる装置が、周期的に変化するガイド信号を生成し、ガイド信号を無線信号よりも低い周波数で、該無線信号と共に相手側の装置へ送信し、第１及び第２の装置のうち受信側となる装置が、任意の時点で相手側の装置から発せられたガイド信号を所定の時間幅をもって受信し、所定の時間幅をもって受信したガイド信号の信号強度の変化を取得し、ガイド信号の所定の時間幅における信号強度の変化を示すデータを、一定期間分のガイド信号について保存し、一定期間分のガイド信号の信号強度の変化に基づいて、相手側の装置から受信する無線信号の信号強度の変化を予測することを特徴とする干渉予測方法を提供するものである。
【００１８】
また、上記目的を達成するため、本発明は、第７の態様として、基地局と少なくとも一つの通信装置との間で無線信号を用いて情報を送受信する移動体通信システムにおける干渉予測方法であって、基地局が、周期的に変化する下りガイド信号を生成し、下りガイド信号を無線信号よりも低い周波数で、該無線信号と共に各通信装置へ送信し、通信装置のそれぞれが、任意の時点で基地局から発せられた下りガイド信号を所定の時間幅をもって受信し、所定の時間幅をもって受信した下りガイド信号の信号強度の変化を取得し、下りガイド信号の所定の時間幅における信号強度の変化を示すデータを、一定期間分の下りガイド信号について保存し、一定期間分の下りガイド信号の信号強度の変化に基づいて、基地局から受信する無線信号の信号強度の変化を予測することにより、通信装置のそれぞれにおける無線信号の干渉を予測すると共に、各通信装置のそれぞれが、周期的に変化する上りガイド信号を生成し、上りガイド信号を無線信号よりも低い周波数で、該無線信号と共に基地局へ送信し、基地局が、任意の時点で通信装置のそれぞれから発せられた上りガイド信号を所定の時間幅をもって受信し、所定の時間幅をもって受信した上りガイド信号の信号強度の変化を取得し、上りガイド信号の所定の時間幅における信号強度の変化を示すデータを、一定期間分の上りガイド信号について保存し、一定期間分の上りガイド信号の信号強度の変化に基づいて、通信装置それぞれから受信する無線信号の信号強度の変化を予測することにより、基地局における無線信号の干渉を予測することを特徴とする干渉予測方法を提供するものである。
【００１９】
【発明の実施の形態】
〔発明の原理〕
本発明の原理について説明する。
図２に示すように、送信側の装置と受信側の装置との間に建造物等が複数存在する場合、受信側の装置には反射波のみならず回折波も到達することになる。この時、反射波の経路長は回折波の経路長よりも長いため、回折波は反射波よりも先に受信側の装置へ到達する。
【００２０】
また、波動が回折を起こす際には、周波数が高いほど回折量（角度）は小さく、周波数が低いほど回折量は大きくなる。
このため、障害物を介在して移動する同一の発信源から周波数が異なる二つの波動を発信した場合には、受信側においては周波数が低い波動の回折波が先に観測されることとなる。例えば、図２において、送信側の装置が矢印で示す方向へ移動する場合に受信側の装置において観測される信号の電力値は、図３に示すように、まず周波数の低い信号の電力値が増加し、その後に周波数の高い信号の電力値が増加することとなる。
よって、本発明おいて、送信側の装置は、実際に情報を送受信するための信号と共に、これよりも低い周波数のガイド信号を送信する。受信側の装置は、受信したガイド信号の電力値の変動に基づいて、実際に情報を送受信するための信号の周波数での干渉を予測する。これにより、情報を送受信する信号の周波数においては、干渉が発生する前に、その影響を低減するための対策を講じることができる。
【００２１】
〔第１の実施形態〕
本発明を好適に実施した第１の実施形態について説明する。
図１に、本実施形態にかかる移動体通信システムを示す。この移動体通信システムは基地局１００と携帯端末２００とを有する。
【００２２】
基地局１００は、アンテナ１０１、送受信部１０２、制御部１０３、主信号処理部１０４、ガイド信号処理部１０５を有する。
【００２３】
アンテナ１０１は、電磁波により信号を送受信するためのアンテナである。送受信部１０２は、電気信号を無線信号へ変調してアンテナ１０１へ出力したり、アンテナ１０１から入力された無線信号を電気信号へ復調して主信号処理部１０４へ出力したりする。制御部１０３は、基地局１００の各部の動作を制御する。主信号処理部１０４は、携帯端末２００へ送信する情報を表す電気信号を生成して送受信部１０２へ出力する。また、送受信部１０２から入力された電気信号によって表される情報を処理する。ガイド信号処理部１０５は、一定周期で繰り返される自己相関性及び相互相関性を有する符号列を電気信号で生成し、送受信部１０２へ出力する。
【００２４】
携帯端末２００は、アンテナ２０１、送受信部２０２、制御部２０３、主信号処理部２０４及びガイド信号処理部２０５を有する。
アンテナ２０１は、電波により信号を送受信するためのアンテナである。送受信部２０２は、電気信号を無線信号へ変調したり、無線信号を電気信号へ復調したりする。送受信部２０２は、主信号の無線信号を変換した電気信号は主信号処理部２０４へ出力し、ガイド信号の無線信号を変換した電気信号をガイド信号処理部２０５へ出力する。制御部２０３は、携帯端末２００の各部の動作を制御する。主信号処理部２０４は、送受信部２０２から入力された電気信号によって表される情報を処理する。また、基地局１００へ送信する情報を表す電気信号を生成し、送受信部２０２へ出力する。ガイド信号処理部２０５は、送受信部２０２が入力した電気信号へ変換されたガイド信号を処理する。
【００２５】
ガイド信号処理部２０５は、検出部２０５１、記憶部２０５２及び予測部２０５３を有する。
検出部２０５１は、送受信部２０２から入力された電気信号に基づいて、干渉波の数及びタイミングを検出する。記憶部２０５２は、ガイド信号の測定結果を一定期間分保存する。予測部２０５３は、時間毎の電力値の変化から、希望波の周波数帯における干渉波の干渉タイミングを予測する。
【００２６】
携帯端末２００が干渉波を推定する手順を説明する。
基地局１００において送受信部１０２は、主信号処理部１０４が生成した情報を無線信号に変換して主信号を生成すると共に、ガイド信号処理部１０５が生成したガイド信号を主信号よりも低い周波数の無線信号に変換してガイド信号を生成する。制御部１０３は、アンテナ１０１を介して主信号とガイド信号とを携帯端末２００へ送信する。
【００２７】
携帯端末２００において制御部２０３は、アンテナ２０１介してタイミングをずらして（所定の時間幅をもって）受信したガイド信号を、送受信部２０２で電気信号に変換し、ガイド信号処理部２０５へ出力する。ガイド信号処理部２０５が電気信号に変換されたガイド信号を送受信部２０２から取得すると、検出部２０５１は、受信タイミング毎の電力値から、干渉波の本数とタイミングとを検出する。
【００２８】
図４（ａ）に、希望波として受信している信号の受信タイミングを基準とした場合のガイド信号の電力値の変化を示す。縦軸は受信したガイド信号の電力値、横軸は希望波を受信してから経過した時間を示す。
主信号の受信タイミングと同時に観測されるガイド信号のピークは、主信号と同じ伝搬経路を経て基地局から到達するガイド信号、すなわち信号強度が最も大きいガイド信号（希望ガイド信号）を示している。また、希望ガイド信号と異なる受信タイミングで観測される電力値のピークは、主信号とは異なる伝搬経路を経て基地局から到達するガイド信号、すなわち干渉波によるガイド信号（干渉ガイド信号）を示している。この時、ピークが現れる位置は、希望ガイド信号に対する干渉ガイド信号の位相ずれを表し、ピークの高さが干渉ガイド信号の電力値（強度）を表すこととなる。
よって、タイミングをずらしてガイド信号を受信することにより、干渉波の本数とそれらの受信タイミングとを特定することが可能となる。なお、ガイド信号は自己相関性及び相互相関性を有する符号列であるため、タイミングをずらして受信しても、基地局から別のタイミングで送信されたガイド信号と区別して受信することが可能である。
記憶部２０５２は、ガイド信号の測定結果を所定の時間分保存する。
【００２９】
図４（ｂ）に、（ａ）から任意時間経過した後のガイド信号の電力値の変化を示す。
（ａ）と同様に、希望ガイド信号とは異なる受信タイミングで観測される電力値のピークは、干渉ガイド信号によるものである。予測部２０５３は、記憶部２０５２に保存されているガイド信号の測定結果と新たに検出部２０５１から取得したガイド信号の測定結果とを比較して、任意時間の間に希望ガイド信号に対する干渉ガイド信号の位相ずれ及び強度がどのように変化したかを算出する。
【００３０】
図２に示したように、ガイド信号は、回折効果によって主信号よりも早いタイミングで携帯端末２００へ到達する。このため、予測部２０５３は、ガイド信号の位相ずれ及び強度の変化に基づいて、主信号における干渉波の受信タイミング及び強度の変化を予測する。
例えば、希望ガイド信号に対する干渉ガイド信号の受信タイミングが任意時間前よりも小さくなった場合、主信号においても希望波に対する干渉波の位相ずれが小さくなると予測する。
また、干渉ガイド信号の電力値が任意時間前よりも大きくなった場合は、主信号においても干渉波の電力値が大きくなると予測する。
【００３１】
予測部２０５３が、主信号における干渉波の受信タイミング及び強度の変化を予測することにより、制御部２０３は干渉によってＳＩＲ（希望波干渉波比）が低下しないように対策を講じることができる。
【００３２】
また、主信号の電力値が落ち込んだ場合でも、ガイド信号の状態を参照することで、制御部２０３は主信号の電力値の低下が瞬間的なものであるか継続的なものであるかを認識できる。例えば制御部２０３は、予測部２０５３が干渉の影響を予測した受信タイミングにおいて主信号の電力値が低下した場合には、電力値の低下は瞬間的なものであると認識する。
【００３３】
なお、移動体通信システムに携帯端末２００が複数存在する場合でも、基地局１００は単独のチャネルを用いて各携帯端末２００にガイド信号を送信する。各携帯端末２００がガイド信号処理部２０５の予測部２０５３において主信号の干渉を影響を予測することで、全ての携帯端末２００において干渉の影響を事前に察知してその影響を受けないように対策を講じることが可能となる。
【００３４】
このように、本実施形態によれば、干渉の影響を事前に察知して、その影響を受けないようにすることが可能となる。
【００３５】
〔第２の実施形態〕
本発明を好適に実施した第２の実施形態について説明する。
図５に、本実施形態にかかる移動体通信システムを示す。この移動体通信システムは基地局１００と携帯端末２００とを有する。
【００３６】
基地局１００は、アンテナ１０１、送受信部１０２、制御部１０３、主信号処理部１０４、ガイド信号処理部１０５を有する。
【００３７】
アンテナ１０１は、電磁波により信号を送受信するためのアンテナである。送受信部１０２は、電気信号を無線信号へ変調してアンテナ１０１へ出力したり、アンテナ１０１から入力された無線信号を電気信号へ復調して主信号処理部１０４やガイド信号処理部１０５へ出力したりする。制御部１０３は、基地局１００の各部の動作を制御する。主信号処理部１０４は、携帯端末２００へ送信する情報を表す電気信号を生成して送受信部１０２へ出力する。また、送受信部１０２から入力された電気信号によって表される情報を処理する。ガイド信号処理部１０５は、一定周期で繰り返される自己相関性及び相互相関性を有する符号列を電気信号で生成し、送受信部１０２へ出力する。また、送受信部１０２から電気信号に変換されたうえで入力されたガイド信号を処理する。
【００３８】
ガイド信号処理部１０５は、検出部１０５１、記憶部１０５２、予測部１０５３及び生成部１０５４を有する。
検出部１０５１は、送受信部１０２から入力された電気信号を基づいて、ガイド信号の干渉波の数及びそれらの受信タイミングを検出する。記憶部１０５２は、ガイド信号の測定結果を一定期間分保存する。予測部１０５３は、時間毎の電力値の変化から、希望波の周波数帯における干渉波の干渉タイミングを予測する。生成部１０５４は、携帯端末２００へ送信するためのガイド信号を生成する。
【００３９】
携帯端末２００は、アンテナ２０１、送受信部２０２、制御部２０３、主信号処理部２０４及びガイド信号処理部２０５を有する。
アンテナ２０１は、電波により信号を送受信するためのアンテナである。送受信部２０２は、電気信号を無線信号へ変調したり、無線信号を電気信号へ復調したりする。送受信部２０２は、主信号の無線信号を変換した電気信号は主信号処理部２０４へ出力し、ガイド信号の無線信号を変換した電気信号をガイド信号処理部２０５へ出力する。制御部２０３は、携帯端末２００の各部の動作を制御する。主信号処理部２０４は、送受信部２０２から入力された電気信号によって表される情報を処理する。また、基地局１００へ送信する情報を表す電気信号を生成し、送受信部２０２へ出力する。ガイド信号処理部２０５は、送受信部２０２から入力された電気信号へ変換されたガイド信号を処理する。
【００４０】
ガイド信号処理部２０５は、検出部２０５１、記憶部２０５２、予測部２０５３及び生成部２０５４を有する。
検出部２０５１は、送受信部２０２から入力された電気信号に基づいて、干渉波の数及びタイミングを検出する。記憶部２０５２は、ガイド信号の測定結果を一定期間分保存する。予測部２０５３は、時間毎の電力値の変化から、希望波の周波数帯における干渉波の干渉タイミングを予測する。生成部２０５４は、基地局１００へ送信するためのガイド信号を生成する。
【００４１】
本実施形態にかかる移動体通信システムにおいては基地局１００及び携帯端末２００のそれぞれが、第１の実施形態における基地局１００と同様にしてガイド信号を送信し、第１の実施形態における携帯端末２００と同様にしてガイド信号の受信タイミング及び電力値の変化に基づいて主信号の干渉の影響を予測する。
このため、基地局１００及び２００のいずれにおいても、ＳＩＲが低下しないように対策を講じることが可能となる。なお、本実施形態においては相手側に主信号の無線信号の強度を上げるように要求することで、干渉の影響を低減することが可能であるため、主信号における干渉の影響をより低減することが可能となる。
【００４２】
このように、本実施形態にかかる移動体通信システムにおいては、基地局側及び携帯端末側のいずれにおいても、干渉の影響を予測してその影響を受けないように対策をとることが可能となる。
【００４３】
〔第３の実施形態〕
本発明を好適に実施した第３の実施形態について説明する。図６に、本実施形態にかかる移動体通信システムを示す。本実施形態にかかる移動体通信システムは、基地局１００と携帯端末２００（２００ａ〜２００ｎ）を有する。
【００４４】
本実施形態にかかる移動体通信システムを構成する携帯端末２００は、第２の実施形態によるものと同様である。ただし、携帯端末２００ａ〜２００ｎは個別のチャネルを用いて基地局１００へガイド信号（上りガイド信号）を送信する。
【００４５】
また、基地局１００は、第２の実施形態によるものとほぼ同様である。ただし、本実施形態においては、各携帯端末２００から受信した上りガイド信号を各チャネルごとに個別に処理する。
換言すると、各携帯端末２００にはそれぞれ固有のチャネルが割り当てられており、基地局１００のガイド信号処理部１０５において検出部１０５１は、各チャネルごとにガイド信号の干渉波数及び受信タイミングを検出する。また、記憶部１０５２は、各チャネルごとにガイド信号の測定結果を保存する。さらに、予測部１０５３は、各チャネルごとに、時間毎の電力値の変化から主信号の干渉タイミングを予測する。なお、ガイド信号生成部１０５４は、各携帯端末２００へのガイド信号（下りガイド信号）を単独のチャネルで生成する。
【００４６】
すなわち、基地局１００は１チャネルを用いて下りガイド信号を各携帯端末２００へ送信し、各携帯端末２００は、それぞれが個別のチャネルを用いて上りガイド信号を基地局１００へ送信する。このため、移動体通信システム全体としてはｎ＋１チャネルを用いてガイド信号を送受信する。
【００４７】
本実施形態にでは、基地局１００において各携帯端末２００から受信したガイド信号をガイド信号処理部１０５が個別に処理することで、制御部１０３は各携帯端末２００から受信する主信号の干渉の影響を予測して各携帯端末２００ごとに対策を講じることが可能となる。
【００４８】
このように、本実施形態にかかる移動体通信システムによれば、基地局側及び携帯端末側のいずれにおいても、干渉の影響を予測してその影響を受けないように対策をとることが可能となる。
【００４９】
なお、上記各実施形態は本発明の好適な実施の一例であり、本発明はこれに限定されることはない。
例えば、上記各実施形態において予測部は、任意の時点及びこの時点から一定時間経過後において所定の時間幅でのガイド信号の電力値を比較することで、主信号における干渉の影響を予測しているが、３以上の時点から所定の時間幅でのガイド信号の電力値を比較して、干渉の影響を予測するようにしてもよい。
このように、本発明は様々な変形が可能である。
【００５０】
【発明の効果】
以上の説明により明らかなように、本発明によれば、干渉の影響を事前に察知する通信装置、移動体通信システム及び干渉予測方法を提供できる。よって、通信時に発生する干渉の影響を予測して、その影響を低減するように対策を講じることが可能となる。
【図面の簡単な説明】
【図１】本発明を好適に実施した第１の実施形態にかかる移動体通信システムの構成を示す図である。
【図２】受信側の装置に到達する信号を示す図である。
【図３】受信側の装置に信号が到達するタイミングが周波数によって異なる状態を示す図である。
【図４】所定時間内でのガイド信号の電力値の変化を示す図である。
【図５】本発明を好適に実施した第２の実施形態にかかる移動体通信システムの構成を示す図である。
【図６】本発明を好適に実施した第３の実施形態にかかる移動体通信システムの構成を示す図である。
【符号の説明】
１００基地局
１０１、２０１アンテナ
１０２、２０２送受信部
１０３、２０３制御部
１０４、２０４主信号処理部
１０５、２０５ガイド信号処理部
２００携帯端末
１０５１、２０５１検出部
１０５２、２０５２記憶部
１０５３、２０５３予測部
１０５４、２０５４生成部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a communication apparatus, a mobile communication system, and an interference prediction method, and more particularly, to interference of an electromagnetic wave propagating a signal for transmitting / receiving information using an electromagnetic wave having a frequency lower than that of a signal for transmitting / receiving information. The present invention relates to a communication apparatus that predicts occurrence, a mobile communication system, and an interference prediction method.
[0002]
[Prior art]
An electromagnetic wave having a frequency band of about 800 MHz to 2 GHz is widely applied to wireless communication because it has a property of reaching far and being transmitted to some extent behind a building or the like. However, radio waves in this frequency band are also easily reflected by buildings and the like.
[0003]
When a transmitted radio wave is reflected by a building or the like, a “multi-path” is formed in which a plurality of radio wave paths (propagation paths) from a transmitting terminal to a receiving terminal are formed.
When a multipath occurs, a target radio wave arrives at a receiving terminal from a plurality of directions, but radio waves that reach the receiving terminal via each path cause interference.
[0004]
A radio wave (indirect wave) that is reflected by a building or the like and reaches a terminal on the receiving side arrives with a delay in time because the propagation distance is longer than a radio wave (direct wave) that has reached directly. For example, the difference in arrival time between direct waves and indirect waves in an urban area or the like is about several tens of μs, and in the case of an indoor wireless LAN or the like, it is about several tens of ns.
[0005]
When there is a difference in the arrival time of radio waves, signals having different phases arrive at the antenna of the receiving terminal. For this reason, the signal actually received by the receiving terminal is a combination of a desired wave (for example, a direct wave) and an interference wave (for example, an indirect wave). At this time, the interference wave acts as an interference component for the desired wave. When the phases match, the signals strengthen each other, and when the phases are opposite, the signals weaken each other.
[0006]
In the case of mobile communication, either one or both of the transmitting and receiving terminals move, so the frequency differs between the direct wave and the indirect wave due to the influence of the Doppler shift. Furthermore, since the distance between the building or the like causing the indirect wave and each terminal varies, the reception timing differs between the direct wave and the indirect wave.
Therefore, when multipath occurs, the phase relationship between the desired wave and the interference wave changes from time to time, and a “fading” phenomenon occurs in which the amplitude of the combined signal of the desired wave and the interference wave changes significantly. It will be. When fading occurs, in a digital communication system, the desired wave interference wave ratio (SIR) is extremely lowered, and data errors are significantly increased.
[0007]
In the case of “line-of-sight communication” in which the receiving side terminal can receive a direct wave, since the direct wave can be received as a stable standing wave, the strength of the received electric field is unlikely to drop. On the other hand, in the case of “non-line-of-sight communication” in which direct waves cannot be received, a large number of reflected waves and diffracted waves of the same strength are received, and the intensity of the received electric field fluctuates drastically, causing interference due to multipath The effect of becomes significant.
[0008]
As a conventional technique for reducing the influence of interference due to multipath, there is a “propagation path estimation method and interference cancellation apparatus in an interference canceller” disclosed in Patent Document 1.
The invention described in Patent Document 1 eliminates the influence of a propagation path from received data by estimating the characteristics of the propagation path of each path using pilot symbols.
[0009]
[Patent Document 1]
JP 2000-83011 A
[0010]
[Problems to be solved by the invention]
In order to reduce the influence of interference, instead of receiving the signal in which the interference has occurred and removing the influence as in the invention described in Patent Document 1, a change in the received electric field due to the influence is predicted in advance. It is preferable to take some measures.
However, in mobile communication, each terminal can move in any direction, and the direction in which the building that causes the indirect wave is present and the distance from each terminal to the building are not constant. It was difficult to predict the occurrence of
[0011]
The present invention has been made in view of such a problem, and an object of the present invention is to provide a communication device, a mobile communication system, and an interference prediction method that can detect the influence of interference in advance.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, as a first aspect, the present invention is a communication device that transmits and receives information to and from a counterpart device using a radio signal, and generates a guide signal that changes periodically. Means for transmitting a guide signal at a frequency lower than that of the radio signal together with the radio signal to the counterpart device, and receiving a guide signal emitted from the counterpart device at a predetermined time with a predetermined time width. Means for acquiring a change in signal strength of a guide signal received with a predetermined time width, and means for storing data indicating a change in signal strength in a predetermined time width of the guide signal for a guide signal for a predetermined period. And a means for predicting a change in the signal strength of the radio signal received from the counterpart device based on a change in the signal strength of the guide signal for a certain period of time. It is intended to provide.
[0013]
Moreover, in order to achieve the said objective, this invention is a mobile communication system which transmits information using a radio signal from a transmitter to a receiver as a 2nd aspect, Comprising: A transmitter changes periodically. Means for generating a guide signal to be transmitted, and means for transmitting the guide signal to the receiving apparatus together with the radio signal at a frequency lower than that of the radio signal. The receiving apparatus is a guide emitted from the transmitting apparatus at an arbitrary time. Means for receiving a signal with a predetermined time width, means for obtaining a change in signal strength of a guide signal received with a predetermined time width, and data indicating a change in signal strength over a predetermined time width of the guide signal are constant. Means for storing a guide signal for a period; and means for predicting a change in signal strength of a radio signal received from a transmission device based on a change in signal intensity of the guide signal for a certain period; There is provided a mobile communication system, comprising.
[0014]
In order to achieve the above object, according to a third aspect of the present invention, there is provided a mobile communication system that transmits and receives information between a first device and a second device using a radio signal. Each of the first apparatus and the second apparatus includes a means for generating a periodically changing guide signal, a means for transmitting the guide signal to the counterpart apparatus together with the wireless signal at a frequency lower than the wireless signal, Means for receiving a guide signal emitted from a device on the other side at an arbitrary time point with a predetermined time width, means for acquiring a change in signal strength of the guide signal received with a predetermined time width, Data indicating the change in the signal strength in the time width is stored for the guide signal for a certain period, and the radio signal received from the counterpart device based on the change in the signal intensity of the guide signal for the certain period There is provided a mobile communication system; and a means for predicting the change in the No. intensity.
[0015]
In order to achieve the above object, according to a fourth aspect of the present invention, there is provided a mobile communication system that transmits and receives information between a base station and at least one communication device using a radio signal. Means for generating a periodically changing downlink guide signal, means for transmitting the downlink guide signal to each of the communication devices together with the wireless signal at a frequency lower than that of the wireless signal, and each of the communication devices at an arbitrary time point Means for receiving an uplink guide signal emitted from the receiver with a predetermined time width, means for obtaining a change in signal strength of the uplink guide signal received with a predetermined time width, and signal strength of the uplink guide signal in a predetermined time width The data indicating the change in the transmission device is stored for the uplink guide signal for a certain period, and the communication device is based on the change in the signal strength of the uplink guide signal for the certain period. Each communication device has a means for predicting a change in signal strength of a radio signal received from each of the communication devices, each of the communication devices generates a periodically changing uplink guide signal, and an uplink guide signal Means for transmitting to the base station together with the radio signal at a frequency lower than that of the radio signal, means for receiving a downlink guide signal emitted from the base station at an arbitrary time point with a predetermined time width, and receiving with a predetermined time width Means for acquiring a change in signal strength of the downlink guide signal, means for storing data indicating a change in signal strength in a predetermined time width of the downlink guide signal for the downlink guide signal for a certain period, and for a certain period A mobile communication system comprising: means for predicting a change in signal strength of a radio signal received from a base station based on a change in signal strength of a downlink guide signal It is intended to provide.
[0016]
In order to achieve the above object, the present invention provides, as a fifth aspect, an interference prediction method in a mobile communication system that transmits information using a radio signal from a transmission device to a reception device, and the transmission device includes: A periodically changing guide signal is generated, and the guide signal is transmitted from the transmitting device to the receiving device together with the wireless signal at a frequency lower than that of the wireless signal. The receiving device generates a guide emitted from the transmitting device at an arbitrary time. The signal is received with a predetermined time width, the receiving device acquires a change in the signal strength of the guide signal received with the predetermined time width, and the receiving device indicates the change in the signal strength in the predetermined time width of the guide signal. Data is stored for a guide signal for a certain period, and a change in the signal strength of a radio signal is predicted based on a change in the signal intensity of the guide signal for a certain period There is provided a Wataru prediction method.
[0017]
Moreover, in order to achieve the said objective, this invention is the interference prediction method in the mobile communication system which transmits / receives information using a radio signal as a 6th aspect between a 1st apparatus and a 2nd apparatus. In the first and second devices, the transmitting device generates a periodically changing guide signal, and the guide signal is transmitted to the partner device together with the wireless signal at a frequency lower than that of the wireless signal. The guide which is transmitted and the receiving device out of the first and second devices receives the guide signal emitted from the counterpart device at an arbitrary time with a predetermined time width, and receives with a predetermined time width. Obtains the change in signal strength of the signal, stores the data indicating the change in signal strength in the predetermined time width of the guide signal for the guide signal for a certain period, and based on the change in the signal intensity of the guide signal for a certain period Opponent There is provided an interference prediction method characterized by predicting a change in signal strength of a radio signal received from the device.
[0018]
In order to achieve the above object, according to a seventh aspect of the present invention, there is provided an interference prediction method in a mobile communication system that transmits and receives information between a base station and at least one communication device using a radio signal. The base station generates a downlink guide signal that changes periodically, transmits the downlink guide signal to each communication device together with the radio signal at a frequency lower than that of the radio signal, and each of the communication devices has an arbitrary time point. The downlink guide signal transmitted from the base station is received with a predetermined time width, the change of the signal strength of the downlink guide signal received with the predetermined time width is obtained, and the signal strength of the downlink guide signal in the predetermined time width is obtained. Data indicating the change is stored for the downlink guide signal for a certain period, and the signal of the radio signal received from the base station based on the change in the signal strength of the downlink guide signal for a certain period is stored. By predicting the change in intensity, it is possible to predict interference of radio signals in each of the communication devices, and each of the communication devices generates an uplink guide signal that periodically changes, and the uplink guide signal is changed from the radio signal. The base station transmits to the base station together with the radio signal at a low frequency, and the base station receives the uplink guide signal generated from each of the communication devices at an arbitrary time point with a predetermined time width, and the uplink signal received with the predetermined time width. Obtains the change in signal strength of the guide signal, stores the data indicating the change in signal strength in the predetermined time width of the uplink guide signal for the uplink guide signal for a certain period, and the signal strength of the uplink guide signal for a certain period By predicting the change in the signal strength of the radio signal received from each communication device based on the change in the signal, the radio signal interference in the base station is predicted. There is provided an interference prediction method characterized by.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
[Principle of the Invention]
The principle of the present invention will be described.
As shown in FIG. 2, when there are a plurality of buildings or the like between the transmission-side device and the reception-side device, not only the reflected wave but also the diffracted wave reaches the reception-side device. At this time, since the path length of the reflected wave is longer than the path length of the diffracted wave, the diffracted wave reaches the reception-side device before the reflected wave.
[0020]
When the wave is diffracted, the higher the frequency, the smaller the diffraction amount (angle), and the lower the frequency, the larger the diffraction amount.
For this reason, when two waves having different frequencies are transmitted from the same transmission source moving through an obstacle, a diffracted wave having a low frequency is first observed on the receiving side. For example, in FIG. 2, when the transmitting apparatus moves in the direction indicated by the arrow, the power value of the signal observed in the receiving apparatus is, as shown in FIG. After that, the power value of a signal having a high frequency increases.
Therefore, in the present invention, the transmission-side apparatus transmits a guide signal having a frequency lower than this together with a signal for actually transmitting and receiving information. The reception-side apparatus predicts interference at the frequency of the signal for actually transmitting / receiving information, based on the variation in the power value of the received guide signal. Thereby, in the frequency of the signal which transmits / receives information, measures can be taken to reduce the influence before interference occurs.
[0021]
[First Embodiment]
A first embodiment in which the present invention is suitably implemented will be described.
FIG. 1 shows a mobile communication system according to the present embodiment. This mobile communication system includes a base station 100 and a mobile terminal 200.
[0022]
The base station 100 includes an antenna 101, a transmission / reception unit 102, a control unit 103, a main signal processing unit 104, and a guide signal processing unit 105.
[0023]
The antenna 101 is an antenna for transmitting and receiving signals using electromagnetic waves. The transmission / reception unit 102 modulates an electric signal into a radio signal and outputs the radio signal to the antenna 101, or demodulates the radio signal input from the antenna 101 into an electric signal and outputs the electric signal to the main signal processing unit 104. The control unit 103 controls the operation of each unit of the base station 100. The main signal processing unit 104 generates an electrical signal representing information to be transmitted to the mobile terminal 200 and outputs the electrical signal to the transmission / reception unit 102. Also, the information represented by the electrical signal input from the transmission / reception unit 102 is processed. The guide signal processing unit 105 generates a code sequence having autocorrelation and cross-correlation that is repeated at a constant period as an electrical signal, and outputs the code sequence to the transmission / reception unit 102.
[0024]
The portable terminal 200 includes an antenna 201, a transmission / reception unit 202, a control unit 203, a main signal processing unit 204, and a guide signal processing unit 205.
The antenna 201 is an antenna for transmitting and receiving signals by radio waves. The transmission / reception unit 202 modulates an electric signal into a radio signal or demodulates the radio signal into an electric signal. The transmission / reception unit 202 outputs the electrical signal obtained by converting the radio signal of the main signal to the main signal processing unit 204, and outputs the electrical signal obtained by converting the radio signal of the guide signal to the guide signal processing unit 205. The control unit 203 controls the operation of each unit of the mobile terminal 200. The main signal processing unit 204 processes information represented by the electrical signal input from the transmission / reception unit 202. In addition, an electrical signal representing information to be transmitted to base station 100 is generated and output to transmission / reception section 202. The guide signal processing unit 205 processes the guide signal converted into the electrical signal input by the transmission / reception unit 202.
[0025]
The guide signal processing unit 205 includes a detection unit 2051, a storage unit 2052, and a prediction unit 2053.
The detection unit 2051 detects the number and timing of interference waves based on the electrical signal input from the transmission / reception unit 202. The storage unit 2052 stores the measurement result of the guide signal for a certain period. The prediction unit 2053 predicts the interference timing of the interference wave in the frequency band of the desired wave from the change in the power value for each time.
[0026]
A procedure for the mobile terminal 200 to estimate the interference wave will be described.
In the base station 100, the transmission / reception unit 102 converts the information generated by the main signal processing unit 104 into a radio signal to generate a main signal, and the guide signal generated by the guide signal processing unit 105 has a frequency lower than that of the main signal. A guide signal is generated by converting into a radio signal. The control unit 103 transmits the main signal and the guide signal to the mobile terminal 200 via the antenna 101.
[0027]
In the portable terminal 200, the control unit 203 converts the received guide signal via the antenna 201 (with a predetermined time width) into an electrical signal by the transmission / reception unit 202 and outputs the electrical signal to the guide signal processing unit 205. When the guide signal processing unit 205 acquires the guide signal converted into an electrical signal from the transmission / reception unit 202, the detection unit 2051 detects the number and timing of interference waves from the power value at each reception timing.
[0028]
FIG. 4A shows a change in the power value of the guide signal when the reception timing of the signal received as the desired wave is used as a reference. The vertical axis represents the power value of the received guide signal, and the horizontal axis represents the time elapsed since the desired wave was received.
The peak of the guide signal that is observed simultaneously with the reception timing of the main signal indicates a guide signal that arrives from the base station through the same propagation path as the main signal, that is, a guide signal having the highest signal strength (desired guide signal). The peak of the power value observed at a reception timing different from the desired guide signal indicates a guide signal that arrives from the base station through a propagation path different from the main signal, that is, a guide signal (interference guide signal) due to an interference wave. Yes. At this time, the position where the peak appears represents the phase shift of the interference guide signal with respect to the desired guide signal, and the height of the peak represents the power value (intensity) of the interference guide signal.
Therefore, by receiving the guide signal at different timings, it is possible to specify the number of interference waves and their reception timing. Since the guide signal is a code string having autocorrelation and cross-correlation, it can be received separately from the guide signal transmitted at a different timing from the base station, even if the timing is shifted. is there.
The storage unit 2052 stores the measurement result of the guide signal for a predetermined time.
[0029]
FIG. 4B shows a change in the power value of the guide signal after an arbitrary time has elapsed from (a).
Similar to (a), the peak of the power value observed at a reception timing different from the desired guide signal is due to the interference guide signal. The prediction unit 2053 compares the measurement result of the guide signal stored in the storage unit 2052 with the measurement result of the guide signal newly acquired from the detection unit 2051, and the interference guide signal for the desired guide signal during an arbitrary time. It is calculated how the phase shift and the intensity of the change.
[0030]
As shown in FIG. 2, the guide signal reaches the mobile terminal 200 at a timing earlier than the main signal due to the diffraction effect. For this reason, the prediction unit 2053 predicts the reception timing and intensity change of the interference wave in the main signal based on the phase shift and intensity change of the guide signal.
For example, when the reception timing of the interference guide signal with respect to the desired guide signal becomes smaller than an arbitrary time before, it is predicted that the phase shift of the interference wave with respect to the desired wave also decreases in the main signal.
Further, when the power value of the interference guide signal becomes larger than that before an arbitrary time, it is predicted that the power value of the interference wave also increases in the main signal.
[0031]
When the prediction unit 2053 predicts the change in the reception timing and intensity of the interference wave in the main signal, the control unit 203 can take measures so that the SIR (desired wave interference wave ratio) does not decrease due to interference.
[0032]
Further, even when the power value of the main signal drops, the control unit 203 can determine whether the power value decrease of the main signal is instantaneous or continuous by referring to the state of the guide signal. Can be recognized. For example, the control unit 203 recognizes that the power value decrease is instantaneous when the power value of the main signal decreases at the reception timing at which the prediction unit 2053 predicts the influence of interference.
[0033]
Even when there are a plurality of mobile terminals 200 in the mobile communication system, base station 100 transmits a guide signal to each mobile terminal 200 using a single channel. Each mobile terminal 200 predicts the influence of main signal interference in the prediction unit 2053 of the guide signal processing unit 205, so that all the mobile terminals 200 detect the influence of interference in advance and take measures to avoid the influence. Can be taken.
[0034]
As described above, according to the present embodiment, it is possible to detect the influence of interference in advance and avoid the influence.
[0035]
[Second Embodiment]
A second embodiment in which the present invention is suitably implemented will be described.
FIG. 5 shows a mobile communication system according to the present embodiment. This mobile communication system includes a base station 100 and a mobile terminal 200.
[0036]
The base station 100 includes an antenna 101, a transmission / reception unit 102, a control unit 103, a main signal processing unit 104, and a guide signal processing unit 105.
[0037]
The antenna 101 is an antenna for transmitting and receiving signals using electromagnetic waves. The transmission / reception unit 102 modulates an electric signal into a radio signal and outputs it to the antenna 101, or demodulates the radio signal input from the antenna 101 into an electric signal and outputs it to the main signal processing unit 104 and the guide signal processing unit 105. Or The control unit 103 controls the operation of each unit of the base station 100. The main signal processing unit 104 generates an electrical signal representing information to be transmitted to the mobile terminal 200 and outputs the electrical signal to the transmission / reception unit 102. Also, the information represented by the electrical signal input from the transmission / reception unit 102 is processed. The guide signal processing unit 105 generates a code sequence having autocorrelation and cross-correlation that is repeated at a constant period as an electrical signal, and outputs the code sequence to the transmission / reception unit 102. Also, the guide signal input after being converted into an electrical signal from the transmission / reception unit 102 is processed.
[0038]
The guide signal processing unit 105 includes a detection unit 1051, a storage unit 1052, a prediction unit 1053, and a generation unit 1054.
The detection unit 1051 detects the number of interference waves of the guide signal and their reception timing based on the electrical signal input from the transmission / reception unit 102. The storage unit 1052 stores the measurement result of the guide signal for a certain period. The prediction unit 1053 predicts the interference timing of the interference wave in the frequency band of the desired wave from the change in the power value for each time. The generation unit 1054 generates a guide signal for transmission to the mobile terminal 200.
[0039]
The portable terminal 200 includes an antenna 201, a transmission / reception unit 202, a control unit 203, a main signal processing unit 204, and a guide signal processing unit 205.
The antenna 201 is an antenna for transmitting and receiving signals by radio waves. The transmission / reception unit 202 modulates an electric signal into a radio signal or demodulates the radio signal into an electric signal. The transmission / reception unit 202 outputs the electrical signal obtained by converting the radio signal of the main signal to the main signal processing unit 204, and outputs the electrical signal obtained by converting the radio signal of the guide signal to the guide signal processing unit 205. The control unit 203 controls the operation of each unit of the mobile terminal 200. The main signal processing unit 204 processes information represented by the electrical signal input from the transmission / reception unit 202. In addition, an electrical signal representing information to be transmitted to base station 100 is generated and output to transmission / reception section 202. The guide signal processing unit 205 processes the guide signal converted into the electrical signal input from the transmission / reception unit 202.
[0040]
The guide signal processing unit 205 includes a detection unit 2051, a storage unit 2052, a prediction unit 2053, and a generation unit 2054.
The detection unit 2051 detects the number and timing of interference waves based on the electrical signal input from the transmission / reception unit 202. The storage unit 2052 stores the measurement result of the guide signal for a certain period. The prediction unit 2053 predicts the interference timing of the interference wave in the frequency band of the desired wave from the change in the power value for each time. The generation unit 2054 generates a guide signal for transmission to the base station 100.
[0041]
In the mobile communication system according to the present embodiment, each of the base station 100 and the mobile terminal 200 transmits a guide signal in the same manner as the base station 100 in the first embodiment, and the mobile terminal 200 in the first embodiment. In the same manner as described above, the influence of main signal interference is predicted based on the reception timing of the guide signal and the change in the power value.
For this reason, it is possible to take measures so that the SIR does not decrease in either of the base stations 100 and 200. In the present embodiment, it is possible to reduce the influence of interference by requesting the counterpart side to increase the strength of the radio signal of the main signal, so that the influence of interference on the main signal is further reduced. Is possible.
[0042]
Thus, in the mobile communication system according to the present embodiment, it is possible to take measures to predict the influence of interference on both the base station side and the mobile terminal side so as not to be affected. .
[0043]
[Third Embodiment]
A third embodiment in which the present invention is preferably implemented will be described. FIG. 6 shows a mobile communication system according to the present embodiment. The mobile communication system according to the present embodiment includes a base station 100 and mobile terminals 200 (200a to 200n).
[0044]
The mobile terminal 200 constituting the mobile communication system according to the present embodiment is the same as that according to the second embodiment. However, the mobile terminals 200a to 200n transmit guide signals (uplink guide signals) to the base station 100 using individual channels.
[0045]
The base station 100 is substantially the same as that according to the second embodiment. However, in the present embodiment, the uplink guide signal received from each mobile terminal 200 is individually processed for each channel.
In other words, each mobile terminal 200 is assigned a unique channel, and in the guide signal processing unit 105 of the base station 100, the detection unit 1051 detects the interference wave number and reception timing of the guide signal for each channel. Further, the storage unit 1052 stores the measurement result of the guide signal for each channel. Furthermore, the prediction unit 1053 predicts the interference timing of the main signal from the change in the power value for each channel for each channel. Note that the guide signal generation unit 1054 generates a guide signal (downward guide signal) for each mobile terminal 200 using a single channel.
[0046]
That is, the base station 100 transmits a downlink guide signal to each mobile terminal 200 using one channel, and each mobile terminal 200 transmits an uplink guide signal to the base station 100 using an individual channel. For this reason, the entire mobile communication system transmits and receives guide signals using n + 1 channels.
[0047]
In the present embodiment, the guide signal processing unit 105 individually processes the guide signal received from each mobile terminal 200 in the base station 100, so that the control unit 103 is affected by the interference of the main signal received from each mobile terminal 200. Thus, it is possible to take measures for each mobile terminal 200.
[0048]
As described above, according to the mobile communication system according to the present embodiment, it is possible to take measures to predict the influence of interference on both the base station side and the mobile terminal side so as not to be affected. Become.
[0049]
Each of the above embodiments is an example of a preferred embodiment of the present invention, and the present invention is not limited to this.
For example, in each of the above embodiments, the prediction unit predicts the influence of interference in the main signal by comparing the power value of the guide signal in a predetermined time width after a certain time from a certain time point. However, the influence of interference may be predicted by comparing the power values of the guide signal in a predetermined time width from three or more time points.
As described above, the present invention can be variously modified.
[0050]
【The invention's effect】
As is apparent from the above description, according to the present invention, it is possible to provide a communication device, a mobile communication system, and an interference prediction method for detecting the influence of interference in advance. Therefore, it is possible to predict the influence of interference occurring during communication and take measures to reduce the influence.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a mobile communication system according to a first embodiment in which the present invention is preferably implemented.
FIG. 2 is a diagram illustrating a signal reaching a receiving device.
FIG. 3 is a diagram illustrating a state in which the timing at which a signal arrives at a reception-side device varies depending on the frequency.
FIG. 4 is a diagram showing a change in power value of a guide signal within a predetermined time.
FIG. 5 is a diagram showing a configuration of a mobile communication system according to a second embodiment in which the present invention is preferably implemented.
FIG. 6 is a diagram showing a configuration of a mobile communication system according to a third embodiment in which the present invention is preferably implemented.
[Explanation of symbols]
100 base station
101, 201 Antenna
102, 202 Transmission / reception unit
103, 203 Control unit
104, 204 Main signal processor
105, 205 Guide signal processor
200 Mobile terminal
1051, 2051 detector
1052, 2052 Storage unit
1053, 2053 prediction unit
1054, 2054 generator

Claims

A communication device that transmits and receives information to and from a counterpart device using a radio signal,
Means for generating a periodically changing guide signal;
Means for transmitting the guide signal at a frequency lower than that of the wireless signal together with the wireless signal to the counterpart device;
Means for receiving the guide signal emitted from the counterpart device at an arbitrary time point with a predetermined time width;
Means for acquiring a change in signal strength of the guide signal received with the predetermined time width;
Means for storing data indicating changes in signal intensity of the guide signal in the predetermined time width for the guide signal for a certain period;
And a means for predicting a change in the signal strength of the radio signal received from the counterpart device based on a change in the signal strength of the guide signal for the predetermined period.

A mobile communication system for transmitting information from a transmitting device to a receiving device using a radio signal,
Means for generating a periodically changing guide signal;
Means for transmitting the guide signal to the receiving device together with the radio signal at a frequency lower than that of the radio signal;
The receiving device receives the guide signal emitted from the transmitting device at an arbitrary time point with a predetermined time width; and
Means for acquiring a change in signal strength of the guide signal received with the predetermined time width;
Means for storing data indicating changes in signal intensity of the guide signal in the predetermined time width for the guide signal for a certain period;
A mobile communication system comprising: means for predicting a change in signal strength of a radio signal received from the transmission device based on a change in signal strength of the guide signal for the predetermined period.

A mobile communication system for transmitting and receiving information between a first device and a second device using a radio signal,
Each of the first device and the second device is:
Means for generating a periodically changing guide signal;
Means for transmitting the guide signal at a frequency lower than that of the radio signal together with the radio signal to a counterpart device;
Means for receiving the guide signal emitted from the counterpart device at an arbitrary time point with a predetermined time width;
Means for acquiring a change in signal strength of the guide signal received with the predetermined time width;
Means for storing data indicating changes in signal intensity of the guide signal in the predetermined time width for the guide signal for a certain period;
A mobile communication system comprising: means for predicting a change in signal strength of a radio signal received from the counterpart device based on a change in signal strength of the guide signal for the predetermined period.

A mobile communication system that transmits and receives information using a radio signal between a base station and at least one communication device,
The base station generates a periodically changing downlink guide signal; and
Means for transmitting the downlink guide signal to each of the communication devices together with the radio signal at a frequency lower than that of the radio signal;
Means for receiving an uplink guide signal emitted from each of the communication devices at an arbitrary time point with a predetermined time width;
Means for acquiring a change in signal strength of the uplink guide signal received with the predetermined time width;
Means for storing data indicating a change in signal strength of the uplink guide signal in the predetermined time width for the uplink guide signal for a certain period;
A means for predicting a change in signal strength of a radio signal received from each of the communication devices based on a change in signal strength of the uplink guide signal for the predetermined period, for each communication device;
Each of the communication devices
Means for generating a periodically changing uplink guide signal;
Means for transmitting the uplink guide signal to the base station together with the radio signal at a lower frequency than the radio signal;
Means for receiving a downlink guide signal emitted from the base station at an arbitrary time point with a predetermined time width;
Means for acquiring a change in signal strength of a downlink guide signal received with the predetermined time width;
Means for storing data indicating a change in signal strength of the downlink guide signal in the predetermined time width for the downlink guide signal for a certain period;
A mobile communication system comprising: means for predicting a change in signal strength of a radio signal received from the base station based on a change in signal strength of the downlink guide signal for the predetermined period.

An interference prediction method in a mobile communication system for transmitting information from a transmission device to a reception device using a radio signal,
The transmitter generates a periodically changing guide signal;
Transmitting the guide signal from the transmitting device to the receiving device together with the wireless signal at a frequency lower than that of the wireless signal;
The receiving device receives the guide signal emitted from the transmitting device at an arbitrary time with a predetermined time width,
The receiving device acquires a change in signal strength of the guide signal received with the predetermined time width,
The receiving device stores data indicating a change in signal strength in the predetermined time width of the guide signal for a guide signal for a certain period,
An interference prediction method, wherein a change in signal strength of the radio signal is predicted based on a change in signal strength of the guide signal for the predetermined period.

An interference prediction method in a mobile communication system that transmits and receives information using a radio signal between a first device and a second device,
Of the first and second devices, the device serving as the transmitting side is
Generate a periodically changing guide signal,
Transmitting the guide signal at a lower frequency than the wireless signal to the device on the other side together with the wireless signal;
Of the first and second devices, a device serving as a receiving side is
The guide signal issued from the other device at an arbitrary time is received with a predetermined time width,
Obtaining a change in signal strength of the guide signal received with the predetermined time width;
Data indicating a change in signal strength in the predetermined time width of the guide signal is stored for the guide signal for a certain period,
An interference prediction method, wherein a change in signal strength of a radio signal received from the counterpart device is predicted based on a change in signal strength of the guide signal for the predetermined period.

An interference prediction method in a mobile communication system for transmitting and receiving information using a radio signal between a base station and at least one communication device,
The base station is
Generate a periodically changing down guide signal,
Transmitting the downlink guide signal to each communication device together with the radio signal at a frequency lower than that of the radio signal;
Each of the communication devices
A downlink guide signal generated from the base station at an arbitrary time is received with a predetermined time width,
Obtaining a change in signal strength of the downlink guide signal received with the predetermined time width;
Data indicating a change in signal strength in the predetermined time width of the downlink guide signal is stored for the downlink guide signal for a certain period,
Predicting changes in signal strength of radio signals received from the base station based on changes in signal strength of downlink guide signals for the predetermined period, thereby predicting interference of the radio signals in each of the communication devices With
Each of the communication devices
Generate an up-guide signal that changes periodically,
Transmitting the uplink guide signal to the base station together with the radio signal at a lower frequency than the radio signal;
The base station is
Receiving an uplink guide signal generated from each of the communication devices at an arbitrary time point with a predetermined time width;
Obtaining a change in signal strength of the uplink guide signal received with the predetermined time width;
Data indicating a change in signal strength in the predetermined time width of the uplink guide signal is stored for the uplink guide signal for a certain period,
Predicting the radio signal interference in the base station by predicting the signal strength change of the radio signal received from each of the communication devices based on the signal strength change of the uplink guide signal for the predetermined period. An interference prediction method characterized by the above.