JP2004186924A

JP2004186924A - Communication device, mobile communication system, and interference prediction method

Info

Publication number: JP2004186924A
Application number: JP2002350505A
Authority: JP
Inventors: Toru Naoi; 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: 2004-07-02
Anticipated expiration: 2022-12-02
Also published as: JP3730955B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication device, a mobile communication system, and an interference prediction method which are capable of inferring the influences of the interference in advance. <P>SOLUTION: The communication device transmits information to and receives one from the other party device by using a radio signal. A portable terminal 200 has a transmission and reception part 202 for receiving a guide signal changing cyclically which is transmitted with a lower frequency than the radio signal by a base station 100 for a specified duration at an arbitrary point of time, a detecting part 2051 for acquiring changes in the signal intensity of the guide signal received for the specified duration, a storage part 2052 for storing data for showing the changes in the signal intensity of the guide signal for the specified duration with respect to the guide signal for a specified period, and a predicting part 2053 for predicting changes in the signal intensity of the radio signal to be received from the base station 100 on the basis of the changes in the signal intensity of the guide signal for a specified period. <P>COPYRIGHT: (C)2004,JPO&NCIPI

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]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a communication device, a mobile communication system, and an interference prediction method, in particular, by using an electromagnetic wave having a lower frequency than a signal for transmitting and receiving information, and using an electromagnetic wave for transmitting and receiving a signal for transmitting and receiving information. The present invention relates to a communication device for predicting occurrence, a mobile communication system, and an interference prediction method.
[0002]
[Prior art]
BACKGROUND ART Electromagnetic waves in a frequency band of about 800 MHz to 2 GHz have a property of reaching far and transmitting to some extent behind a building or the like, and thus are widely applied to wireless communication. However, radio waves in this frequency band also have the property of being easily reflected by buildings and the like.
[0003]
When a transmitted radio wave is reflected by a building or the like, a “multi-path” occurs in which a plurality of radio wave paths (propagation routes) from the transmitting terminal to the receiving terminal are formed.
When multipath occurs, target radio waves arrive at the terminal on the receiving side from a plurality of directions, but the radio waves arriving at the terminal on the receiving side via the respective paths cause interference.
[0004]
A radio wave (indirect wave) that has been reflected by a building or the like and reached the terminal on the receiving side has a longer propagation distance than a radio wave (direct wave) that has directly arrived, and thus arrives with a time delay. For example, the difference in arrival time between a direct wave and an indirect wave 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]
If a difference occurs in the arrival times of the radio waves, signals having different phases arrive at the antenna of the terminal on the receiving side. Therefore, the signal actually received by the receiving terminal is a signal obtained by combining the desired wave (for example, a direct wave) and the interference wave (for example, an indirect wave). At this time, the interference wave acts as an interference component to the desired wave. When the phases match, the signals reinforce each other, and when the phases are opposite, the signals weaken each other.
[0006]
In the case of mobile communication, one or both of the terminals on the transmitting side and the receiving side move, so that the frequency differs between the direct wave and the indirect wave due to the influence of Doppler shift. Further, the distance between a building or the like that causes an indirect wave and each terminal varies, so that the reception timing differs between the direct wave and the indirect wave.
Therefore, in a state where a multipath is generated, 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 greatly changes. It will be. When fading occurs, in a digital communication system, a desired signal interference ratio (SIR) is extremely reduced, and data errors are significantly increased.
[0007]
In the case of “line-of-sight communication” in which the terminal on the receiving side can receive a direct wave, the strength of the received electric field rarely drops because the direct wave can be received as a stable standing wave. On the other hand, in non-line-of-sight communications where direct waves cannot be received, many reflected or diffracted waves of the same strength will be received, and the strength of the received electric field will fluctuate drastically, resulting in multipath interference. The effect becomes significant.
[0008]
As a conventional technique for reducing the influence of interference due to multipath, there is “a propagation path estimation method and an interference canceller in an interference canceller” disclosed in Patent Document 1.
The invention described in Patent Literature 1 removes the influence of the propagation path from the received data by estimating the propagation path characteristics 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 the interference, instead of receiving the signal in which the interference occurs and removing the effect as in the invention described in Patent Document 1, the change of the received electric field due to the effect is predicted in advance. It is preferable to take some measures.
However, in mobile communication, each terminal can move in an arbitrary direction, and the direction in which a building or the like that causes indirect waves is present or the distance from each terminal to the building or the like is not constant. It was difficult to predict the occurrence.
[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, according to a first aspect of the present invention, there is provided a communication device for transmitting / receiving information to / from a partner device using a wireless signal, and generating a periodically changing guide signal. Means, means for transmitting the guide signal at a lower frequency than the radio signal together with the radio signal to the other device, and receiving the guide signal emitted from the other device at an arbitrary 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 the guide signal for a predetermined period And a means for predicting a change in signal strength of a radio signal received from a partner apparatus based on a change in signal strength of a guide signal for a certain period. It is intended to provide.
[0013]
According to a second aspect of the present invention, there is provided a mobile communication system for transmitting information from a transmitting apparatus to a receiving apparatus by using a radio signal, wherein the transmitting apparatus periodically changes. Means for generating a guide signal to be transmitted, and means for transmitting the guide signal at a lower frequency than the radio signal together with the radio signal to the reception device, wherein the reception device transmits the guide signal emitted from the transmission device at any time. Means for receiving a signal with a predetermined time width, means for acquiring a change in signal strength of a guide signal received with a predetermined time width, and data indicating a change in signal strength in a predetermined time width of the guide signal. Means for storing the guide signal for a period, and means for predicting a change in the signal strength of a radio signal received from the transmitting device based on a change in the signal strength of the guide signal for a certain period. There is provided a mobile communication system, comprising.
[0014]
According to a third aspect of the present invention, there is provided a mobile communication system for transmitting and receiving information between a first device and a second device by using a radio signal. Each of the first device and the second device is configured to generate a periodically changing guide signal, and to transmit the guide signal at a lower frequency than the radio signal to the other device together with the radio signal. Means for receiving a guide signal emitted from the device of the other party at a given time with a predetermined time width, means for acquiring a change in signal strength of the guide signal received with a predetermined time width, and Means for storing data indicating a change in signal strength in the time width for a guide signal for a certain period; and a method for storing a radio signal received from a partner apparatus based on a change in the signal strength of the guide signal for a certain period. There is provided a mobile communication system; and a means for predicting the change in the No. intensity.
[0015]
According to a fourth aspect of the present invention, there is provided a mobile communication system for transmitting and receiving information between a base station and at least one communication device using a radio signal, the base station comprising: Means for generating a downlink guide signal that changes periodically, means for transmitting the downlink guide signal at a lower frequency than the radio signal to each of the communication devices together with the radio signal, and each of the communication devices at any time Means for receiving an uplink guide signal emitted from a predetermined time width, means for acquiring a change in signal strength of an uplink guide signal received with a predetermined time width, and signal strength of the uplink guide signal in a predetermined time width Means for storing data indicating a change in the uplink guide signal for a certain period of time, and a communication device based on the change in the signal strength of 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 apparatuses, wherein each of the communication apparatuses generates a periodically changing uplink guide signal; Means for transmitting to the base station together with the radio signal at a lower frequency than the radio signal, means for receiving the downlink guide signal emitted from the base station at an arbitrary time with a predetermined time width, and reception with a predetermined time width Means for acquiring a change in the signal strength of the downlink guide signal, data indicating a change in the signal strength in a predetermined time width of the downlink guide signal, means for storing the downlink guide signal for a certain period, 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]
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 from a transmitting device to a receiving device by using a radio signal, wherein the transmitting device comprises: Generating a periodically changing guide signal, transmitting the guide signal at a lower frequency than the radio signal together with the radio signal from the transmission device to the reception device, and the reception device transmitting the guide signal at any time from the transmission device; A signal is received with a predetermined time width, the receiving device acquires a change in signal strength of the guide signal received with a predetermined time width, and the receiving device indicates a change in signal strength in the predetermined time width of the guide signal. The method is characterized in that data is stored for a guide signal for a certain period, and a change in the signal strength of the radio signal is predicted based on a change in the signal strength of the guide signal for a certain period. There is provided a Wataru prediction method.
[0017]
In order to achieve the above object, the present invention provides, as a sixth aspect, an interference prediction method in a mobile communication system for transmitting and receiving information between a first device and a second device using a radio signal. The transmitting device among the first and second devices generates a periodically changing guide signal, and transmits the guide signal at a lower frequency than the radio signal to the partner device together with the radio signal. The transmitting and receiving device of the first and second devices receives the guide signal emitted from the other device at an arbitrary time with a predetermined time width, and receives the guide signal with the predetermined time width. Obtain a change in the signal strength of the signal, save data indicating a change in the signal strength in a predetermined time width of the guide signal for the guide signal for a certain period, and based on the change in the signal strength of the guide signal for a certain period. And 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]
To achieve the above object, the present invention provides, as a seventh aspect, an interference prediction method in a mobile communication system for transmitting and receiving information between a base station and at least one communication device using a radio signal. The base station generates a periodically changing downlink guide signal, transmits the downlink guide signal to each communication device together with the radio signal at a lower frequency than the radio signal, and each of the communication devices transmits The downlink guide signal emitted from the base station is received with a predetermined time width, the change in 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. The data indicating the change is stored for the downlink guide signal for a certain period, and based on the change in the signal strength of the downlink guide signal for a certain period, the signal of the radio signal received from the base station is stored. By predicting the change in strength, while predicting the interference of the radio signal in each of the communication devices, each of the communication devices generates a periodically changing uplink guide signal, and sets the uplink guide signal more than the radio signal. At a low frequency, the radio signal is transmitted to the base station together with the radio signal. The base station receives the uplink guide signal emitted from each of the communication devices at an arbitrary time with a predetermined time width, and A change in the signal strength of the guide signal is acquired, and data indicating a change in the signal strength in a predetermined time width of the uplink guide signal is stored for the uplink guide signal for a certain period, and the signal intensity of the uplink guide signal for a certain period is stored. Of the radio signal received from each of the communication devices based on the change in the signal strength, the radio signal interference at the base station is predicted. There is provided an interference prediction method characterized by.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
[Principle of the invention]
The principle of the present invention will be described.
As shown in FIG. 2, when a plurality of buildings and the like exist between the transmitting device and the receiving device, not only reflected waves but also diffracted waves reach the receiving 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 receiving side device before the reflected wave.
[0020]
When a wave causes diffraction, the higher the frequency, the smaller the amount of diffraction (angle), and the lower the frequency, the greater the amount of diffraction.
Therefore, when two waves having different frequencies are transmitted from the same transmission source moving via an obstacle, a diffracted wave having a low frequency is first observed on the receiving side. For example, in FIG. 2, when the transmitting device moves in the direction indicated by the arrow, the power value of the signal observed at the receiving device is, as shown in FIG. After that, the power value of the high-frequency signal increases.
Therefore, in the present invention, the transmitting device transmits a guide signal having a lower frequency than the signal for actually transmitting and receiving information. The device on the receiving side predicts interference at the frequency of the signal for actually transmitting and receiving information based on the fluctuation of the power value of the received guide signal. As a result, it is possible to take measures to reduce the influence of the frequency of the signal for transmitting and receiving information before the interference occurs.
[0021]
[First Embodiment]
First Embodiment A preferred embodiment of the present invention will be described.
FIG. 1 shows a mobile communication system according to the present embodiment. This mobile communication system has 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 signal to the antenna 101, or demodulates a radio signal input from the antenna 101 into an electric signal and outputs the 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 electric signal representing information to be transmitted to the mobile terminal 200, and outputs the generated electric signal to the transmission / reception unit 102. Also, it processes information represented by the electric signal input from the transmission / reception unit 102. The guide signal processing unit 105 generates a code string having auto-correlation and cross-correlation that is repeated at a constant cycle as an electric signal, and outputs it to the transmission / reception unit 102.
[0024]
The mobile terminal 200 includes an antenna 201, a transmitting / receiving 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 wireless signal or demodulates a wireless signal into an electric signal. The transmission / reception unit 202 outputs the electric signal obtained by converting the radio signal of the main signal to the main signal processing unit 204, and outputs the electric 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 electric signal input from the transmission / reception unit 202. Further, it generates an electric signal representing information to be transmitted to base station 100 and outputs the signal to transmitting / receiving section 202. The guide signal processing unit 205 processes the guide signal converted into the electric 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 electric 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 in which the mobile terminal 200 estimates an interference wave will be described.
In base station 100, transmitting / receiving section 102 converts the information generated by main signal processing section 104 into a radio signal to generate a main signal, and converts the guide signal generated by guide signal processing section 105 to a signal having a lower frequency than the main signal. The signal is converted into a radio signal to generate a guide 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 mobile terminal 200, the control unit 203 converts the guide signal received at a shifted timing (with a predetermined time width) via the antenna 201 into an electric signal in the transmitting / receiving unit 202 and outputs the electric signal to the guide signal processing unit 205. When the guide signal processing unit 205 acquires the guide signal converted into the electric signal from the transmission / reception unit 202, the detection unit 2051 detects the number and timing of the interference waves from the power value at each reception timing.
[0028]
FIG. 4A shows a change in the power value of the guide signal based on the reception timing of the signal received as the desired wave. The vertical axis indicates the power value of the received guide signal, and the horizontal axis indicates the time elapsed after receiving the desired wave.
The peak of the guide signal observed at the same time as the reception timing of the main signal indicates a guide signal arriving from the base station via 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 that of the desired guide signal indicates a guide signal arriving from the base station via a propagation path different from that of the main signal, that is, a guide signal (interference guide signal) due to an interference wave. I have. At this time, the position where the peak appears indicates the phase shift of the interference guide signal with respect to the desired guide signal, and the height of the peak indicates the power value (intensity) of the interference guide signal.
Therefore, by receiving the guide signal with the timing shifted, it is possible to specify the number of interference waves and their reception timing. Since the guide signal is a code string having auto-correlation and cross-correlation, it is possible to receive the guide signal separately from the guide signal transmitted from the base station at a different timing, 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 elapse of an arbitrary time from FIG.
As in (a), the peak of the power value observed at a reception timing different from that of 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 determines the interference guide signal for the desired guide signal during an arbitrary time. Are calculated as to how the phase shift and the intensity have changed.
[0030]
As shown in FIG. 2, the guide signal reaches the portable terminal 200 at a timing earlier than the main signal due to the diffraction effect. For this reason, the prediction unit 2053 predicts a change in the reception timing and the strength of the interference wave in the main signal based on the phase shift and the change in the strength of the guide signal.
For example, if the reception timing of the interference guide signal with respect to the desired guide signal becomes smaller than the time before the arbitrary time, it is predicted that the phase shift of the interference wave with respect to the desired wave in the main signal also becomes smaller.
Further, when the power value of the interference guide signal becomes larger than that before the arbitrary time, it is predicted that the power value of the interference wave becomes larger also in the main signal.
[0031]
The prediction unit 2053 predicts a change in the reception timing and intensity of the interference wave in the main signal, so that the control unit 203 can take measures to prevent the SIR (desired wave interference wave ratio) from being reduced due to the interference.
[0032]
In addition, even when the power value of the main signal drops, the control unit 203 refers to the state of the guide signal to determine whether the power value of the main signal is instantaneous or continuous. I can recognize. For example, when the power value of the main signal decreases at the reception timing at which the prediction unit 2053 predicts the influence of the interference, the control unit 203 recognizes that the reduction in the power value is instantaneous.
[0033]
Note that even when a plurality of mobile terminals 200 exist in the mobile communication system, the base station 100 transmits a guide signal to each mobile terminal 200 using a single channel. Each mobile terminal 200 predicts the influence of the interference of the main signal in the prediction unit 2053 of the guide signal processing unit 205, so that all mobile terminals 200 detect the influence of the interference in advance and take measures to prevent 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 not to receive the influence.
[0035]
[Second embodiment]
A second embodiment in which the present invention is preferably implemented will be described.
FIG. 5 shows a mobile communication system according to the present embodiment. This mobile communication system has 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 wireless signal and outputs the signal to the antenna 101, or demodulates a wireless signal input from the antenna 101 into an electric signal and outputs the signal to the main signal processing unit 104 or 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 electric signal representing information to be transmitted to the mobile terminal 200, and outputs the generated electric signal to the transmission / reception unit 102. Also, it processes information represented by the electric signal input from the transmission / reception unit 102. The guide signal processing unit 105 generates a code string having auto-correlation and cross-correlation that is repeated at a constant period as an electric signal, and outputs the code string to the transmission / reception unit 102. In addition, the guide signal is converted into an electric signal from the transmission / reception unit 102 and then 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 electric 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 to be transmitted to the mobile terminal 200.
[0039]
The mobile terminal 200 includes an antenna 201, a transmitting / receiving 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 wireless signal or demodulates a wireless signal into an electric signal. The transmission / reception unit 202 outputs the electric signal obtained by converting the radio signal of the main signal to the main signal processing unit 204, and outputs the electric 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 electric signal input from the transmission / reception unit 202. Further, it generates an electric signal representing information to be transmitted to base station 100 and outputs the signal to transmitting / receiving section 202. The guide signal processing unit 205 processes the guide signal converted into an electric 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 electric 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 to be transmitted 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 according to the first embodiment, and the mobile terminal 200 according to the first embodiment. In the same manner as described above, the influence of the interference of the main signal is predicted based on the change in the reception timing and the power value of the guide signal.
For this reason, it is possible to take measures so that the SIR does not decrease in any of the base stations 100 and 200. In the present embodiment, the effect of interference can be reduced by requesting the other party to increase the strength of the radio signal of the main signal. Becomes possible.
[0042]
As described above, in the mobile communication system according to the present embodiment, it is possible to predict the influence of interference and take measures to prevent the influence on both the base station side and the portable terminal side. .
[0043]
[Third embodiment]
A third preferred embodiment of the present invention 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 configuring 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 almost 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 the detection unit 1051 in the guide signal processing unit 105 of the base station 100 detects the number of interference waves and reception timing of the guide signal for each channel. The storage unit 1052 stores the measurement result of the guide signal for each channel. Further, the prediction unit 1053 predicts, for each channel, the interference timing of the main signal from the change in the power value over time. Note that the guide signal generation unit 1054 generates a guide signal (downlink guide signal) to each mobile terminal 200 through a single channel.
[0046]
That is, 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 base station 100 using each individual channel. For this reason, the mobile communication system as a whole 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 can control the influence of the interference of the main signal received from each mobile terminal 200. And measures can be taken for each mobile terminal 200.
[0048]
As described above, according to the mobile communication system according to the present embodiment, it is possible to predict the influence of interference and take measures to prevent the influence on both the base station side and the portable terminal side. Become.
[0049]
The above embodiments are examples of preferred embodiments of the present invention, and the present invention is not limited to these embodiments.
For example, in each of the above embodiments, the prediction unit predicts the influence of interference on the main signal by comparing the power value of the guide signal at a predetermined time width at a given time and after a certain period of time from this time. However, the influence of interference may be predicted by comparing the power values of the guide signals within 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 clear 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 effect of interference occurring during communication and take measures to reduce the effect.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a mobile communication system according to a first embodiment of the present invention;
FIG. 2 is a diagram illustrating a signal reaching a device on a receiving side.
FIG. 3 is a diagram illustrating a state in which the timing at which a signal reaches a receiving-side device varies depending on the frequency.
FIG. 4 is a diagram showing a change in a 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 illustrating a configuration of a mobile communication system according to a third embodiment of the present invention;
[Explanation of symbols]
100 base stations
101, 201 antenna
102, 202 transceiver
103, 203 control unit
104, 204 main signal processing unit
105, 205 Guide signal processing unit
200 mobile terminal
1051, 2051 detection unit
1052, 2052 storage unit
1053, 2053 Prediction unit
1054, 2054 generator

Claims

A communication device that transmits and receives information to and from a partner device using a wireless signal,
Means for generating a periodically changing guide signal;
Means for transmitting the guide signal at a lower frequency than the wireless signal, together with the wireless signal to the device of the other party,
Means for receiving the guide signal emitted from the partner device at an arbitrary time 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 a change in signal strength in the predetermined time width of the guide signal, for a guide signal for a certain period,
Means for predicting a change in the signal strength of the radio signal received from the partner apparatus based on a change in the signal strength of the guide signal for the predetermined period.

A mobile communication system that transmits information using a radio signal from a transmitting device to a receiving device,
Means for generating a periodically changing guide signal,
Means for transmitting the guide signal at a lower frequency than the wireless signal to the receiving device together with the wireless signal,
Means for receiving the guide signal emitted from the transmitting apparatus at an arbitrary time 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 a change in signal strength in the predetermined time width of the guide signal, for a guide signal for a certain period,
Means for predicting a change in the signal strength of the radio signal received from the transmitting device based on a change in the 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 wireless signal,
Each of the first device and the second device,
Means for generating a periodically changing guide signal;
Means for transmitting the guide signal at a lower frequency than the wireless signal, together with the wireless signal to a device of the other party,
Means for receiving the guide signal emitted from the other device at an arbitrary time 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 a change in signal strength in the predetermined time width of the guide signal, for a guide signal for a certain period,
Means for predicting a change in the signal strength of the radio signal received from the partner apparatus based on a change in the 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,
Means for transmitting the downlink guide signal at a lower frequency than the radio signal to each of the communication devices together with the radio signal,
Means for receiving an uplink guide signal emitted from each of the communication devices at a given time 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 in the predetermined time width of the uplink guide signal, for the uplink guide signal for a certain period,
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 certain 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 at a lower frequency than the radio signal to the base station together with the radio signal,
Means for receiving a downlink guide signal emitted from the base station at a given time with a predetermined time width,
Means for acquiring 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, means for saving the downlink guide signal for a certain period,
Means for predicting a change in the signal strength of the radio signal received from the base station based on a change in the signal strength of the downlink guide signal for the predetermined period.

An interference prediction method in a mobile communication system that transmits information using a radio signal from a transmitting device to a receiving device,
The transmitting device generates a periodically changing guide signal,
The guide signal is transmitted at a lower frequency than the radio signal from the transmission device to the reception device together with the radio 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 the 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 for transmitting and receiving information between a first device and a second device using a wireless signal,
The transmitting device of the first and second devices is:
Generate a periodically changing guide signal,
Transmitting the guide signal at a lower frequency than the radio signal to the other device together with the radio signal;
A device which is a receiving side among the first and second devices,
At any time, receiving the guide signal emitted from the other device with a predetermined time width,
Obtain 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 a guide signal for a predetermined period,
An interference prediction method, wherein a change in signal strength of a radio signal received from the partner 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 that transmits and receives information using a radio signal between a base station and at least one communication device,
The base station is
Generate a periodically changing downlink guide signal,
Transmitting the downlink guide signal at a lower frequency than the radio signal to each communication device together with the radio signal,
Each of the communication devices,
At any time, receiving a downlink guide signal emitted from the base station with a predetermined time width,
Obtain 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,
Based on the change in the signal strength of the downlink guide signal for the certain period, by predicting the change in the signal strength of the radio signal received from the base station, predict the interference of the radio signal in each of the communication devices Along with
Each of the communication devices,
Generate a periodically changing uplink guide signal,
Transmitting the uplink guide signal at a lower frequency than the radio signal to the base station together with the radio signal;
The base station is
At any time, receiving an uplink guide signal emitted from each of the communication devices with a predetermined time width,
Obtain a change in the 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,
Based on a change in the signal strength of the uplink guide signal for the predetermined period, by predicting a change in the signal strength of a radio signal received from each of the communication devices, predicting interference of the radio signal in the base station. An interference prediction method characterized by the following.