JP2004187135A

JP2004187135A - Managing device and method

Info

Publication number: JP2004187135A
Application number: JP2002353684A
Authority: JP
Inventors: Kazuhiro Okamura; 一弘岡村
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2002-12-05
Filing date: 2002-12-05
Publication date: 2004-07-02

Abstract

<P>PROBLEM TO BE SOLVED: To detect output D/U (desired wave and undesired wave ratio) of a sneak canceler with simple structure. <P>SOLUTION: The sneak canceler 4 calculates the D/U of an inputted signal on the basis of a delay profile in a replica signal generation process and an output D/U detection circuit 5 detects the ouput D/U as the D/U in an outputted signal to be transmitted from a transmitting antenna by using the D/U of the inputted signal which is easily calculated by the sneak canceler 4, power of the inputted signal of the sneak canceler 4, and power of an outputted signal of the sneak canceler 4. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
この発明は、例えば地上波デジタル放送のＳＦＮ（ＳｉｎｇｌｅＦｒｅｑｕｅｎｃｙＮｅｔｗｏｒｋ：単一周波数ネットワーク）中継に使用する回り込みキャンセラの出力Ｄ／Ｕ（希望波不要波比）検知に関するものである。
【０００２】
【従来の技術】
地上波デジタル放送では単一周波数ネットワークを実現するために中継局に回り込みキャンセラを適用する検討が進められている。単一周波数ネットワークでの中継では送信信号周波数と受信信号周波数が同一であるため、送信アンテナから送出された電波が受信信号に回り込み発振を引き起こす可能性がある。発振を防ぐ方法としては、送信アンテナと受信アンテナの物理的距離を離す方法や、回り込みキャンセラを用いて送信信号から回り込み波を除去する方法が考えられている。
【０００３】
また、中継局で受信される信号には直接波の他に山岳や海上で反射して到来する遅延波（親局マルチパス波）が含まれている。回り込みキャンセラは受信信号に含まれる回り込み波の成分と親局マルチパス波の成分を除去する装置であり、送出信号での除去の状況を監視する必要がある。
監視の指数として希望波不要波比（以下「Ｄ／Ｕ」）がある。希望波不要波比の希望波とは親局信号であり、不要波とは親局マルチパスおよび、回り込み波である。そして、希望波不要波比とは、信号に含まれる希望波成分及び不要波成分の比である。回り込みキャンセラ装置の出力信号を監視する項目としてＤ／Ｕの監視は重要である。従来、例えば特開２００１−６０９２４に示すように、Ｄ／Ｕの検知回路はアナログ回路で構成されていた。
【０００４】
【特許文献１】
特開２００１−６０９２４号公報
【０００５】
【発明が解決しようとする課題】
従来のＤ／Ｕ検知回路は以上のようにアナログ回路で構成されているので、デジタル信号処理を用いた回り込みキャンセラの出力Ｄ／Ｕ検知に適用するためには、キャンセラの出力にスイープオシレータなどにより構成する専用の回路を構成しなければならず、装置が大型化するなどの問題点があった。
【０００６】
デジタル信号処理でのＤ／Ｕ検知方法としては遅延プロファイルからＤ／Ｕを検知する方法があるがＦＦＴ、ＩＦＦＴなどの演算が必要であり、回路が大規模になる等の問題があった。
【０００７】
この発明は上記のような問題点を解消するためになされたもので、例えばデジタル信号処理型回り込みキャンセラの出力Ｄ／Ｕを容易に検知することを主な目的とする。
【０００８】
【課題を解決するための手段】
本発明に係る管理装置は、
外部より希望波成分及び希望波成分以外の不要波成分が含まれた信号を受信信号として受信し、受信信号から不要波成分を除去する不要波成分キャンセル処理を行い、不要波成分キャンセル処理後の信号を送信信号として外部に送信するとともに、受信信号中の希望波成分と不要波成分との比を受信信号希望波不要波比として算出するキャンセラ装置に接続され、前記キャンセラ装置の管理を行う管理装置であって、
前記キャンセラ装置から受信信号を入力する受信信号入力部と、
前記キャンセラ装置から送信信号を入力する送信信号入力部と、
前記キャンセラ装置から受信信号希望波不要波比を入力する受信信号希望波不要波比入力部と、
受信信号、送信信号及び受信信号希望波不要波比に基づき、送信信号中の希望波成分と前記キャンセラ装置の不要波成分キャンセル処理で除去できなかった不要波成分との比を送信信号希望波不要波比として算出する送信信号希望波不要波比算出部とを有することを特徴とする。
【０００９】
【発明の実施の形態】
実施の形態１．
図１は同一周波数中継を用いた地上波デジタル放送の回り込みキャンセラを用いた中継局の構成例を示す。
１は中継を行う親局波を受信する中継局受信アンテナ、２は受信フィルタなどで構成されるフロントエンド、３は無線周波数帯から中間周波数帯への周波数変換を行うダウンコンバータ、４は受信信号に含まれる回り込み波の成分、親局マルチパスの成分を除去する不要波成分キャンセル処理及び入力Ｄ／Ｕの検知を行う回り込みキャンセラ（キャンセラ装置）、５は回り込みキャンセラ４の監視、管理を行う出力Ｄ／Ｕ検知回路（管理装置）、６は中間周波数帯から無線周波数帯への周波数変換を行うアップコンバータ、７は電力増幅部、８は送信アンテナである。
ここで、入力Ｄ／Ｕとは、中継局受信アンテナ１で受信された受信信号のＤ／Ｕであり、受信信号希望波不要波比に相当し、出力Ｄ／Ｕとは、送信アンテナ８から送信される送信信号のＤ／Ｕであり、送信信号希望波不要波比に相当する。
【００１０】
中継局受信アンテナ１で受信されたＲＦ（ＲＡＤＩＯＦＲＥＱＵＥＮＣＹ）信号はフロントエンド２とダウンコンバータ３を経てＩＦ（ＩＮＴＥＲＭＥＤＩＡＴＥＦＲＥＱＵＥＮＣＹ）信号に変換される。ダウンコンバータ３によりＩＦ信号に変換された受信信号は、回り込みキャンセラ４により回り込み波、親局マルチパスの除去が行われる。回り込みキャンセラ４により回り込み波、親局マルチパスの除去が行われた信号は、アップコンバータ６によりＲＦ信号へと変換される。ＲＦ信号に変換された信号は電力増幅部７により増幅され送信アンテナ８から送信される。
【００１１】
回り込みキャンセラ４の内部処理回路について説明する。
図１において４０１、４１２は周波数変換器であり、４０２はＡ／Ｄ（アナログ／デジタル）コンバータであり、４０３は直交検波器であり、４０４はＦＦＴ（高速フーリエ変換器）であり、４０５はパイロット信号抽出部であり、４０６は誤差信号出力部であり、４０７はＩＦＦＴ（逆高速フーリエ変換器）であり、４０８はレプリカ生成器であり、４０９は減算器であり、４１０は直交変調器であり、４１１はＤ／Ａ（デジタル／アナログ）コンバータである。
【００１２】
ダウンコンバータ３によりＩＦ信号に変換された信号は周波数変換器４０１によりさらに低い信号に周波数変換されＡ／Ｄコンバータ４０２によりデジタル信号に変換される。Ａ／Ｄコンバータ４０２によりデジタル信号に変換された信号は直交検波器４０３により直交検波が行われ、ベースバンド信号となる。
【００１３】
直交検波器４０３により出力されたベースバンド信号は、ＦＦＴ４０４によりＦＦＴ処理が行われ、時間領域信号から周波数領域信号へと変換される。パイロット信号抽出部４０５では、ＦＦＴ４０４から出力される周波数領域の信号から、予め周波数軸方向の定められた位置に挿入されている、振幅および位相が既知のパイロット信号を抽出する。
【００１４】
誤差信号出力部４０６では、抽出されたパイロット信号に基づいて、親局送信信号のマルチパス波や回り込み波成分の周波数特性を有する誤差信号を算出する。誤差信号出力部４０６にて求められた誤差信号は、ＩＦＦＴ４０７において周波数領域信号から時間領域信号へと変換され、親局送信信号のマルチパスや回り込みの振幅および位相および遅延時間情報を含んだ伝送路推定値としてレプリカ生成器４０８へと送られる。レプリカ生成器４０８では、ＩＦＦＴ４０７からの伝送路推定値と減算器４０９の出力信号から親局マルチパスおよび回り込み波のレプリカ信号を生成する。
【００１５】
減算器４０９では直交検波器４０３からの受信信号とレプリカ生成器４０８からのレプリカ信号が減算される。この減算により受信信号から親局マルチパス波と回り込み波成分を除去する（不要波成分キャンセル処理）。
【００１６】
減算器４０９により親局マルチパス波と回り込み波成分の除去が行われた信号は直交変調器４１０により直交変調される。直交変調器４１０により直交変調された信号はＤ／Ａコンバータ４１１によりデジタルからアナログ信号へと変換される。Ｄ／Ａコンバータ４１１によりアナログ信号へと変換された信号は周波数変換器によりＩＦ信号に変換される。
【００１７】
誤差信号出力部４０６について説明する。図２は誤差信号出力部４０６の構成を示す図である。図２において、４５１は周波数特性検出部であり、４５２はＩＦＦＴであり、４５３は親局直接波変動量推定部であり、４５４はＤ／Ｕ演算部であり、４５５はＦＦＴであり、４５６は誤差信号算出部である。
【００１８】
誤差信号出力部４０６において、周波数特性検出部４５１では、振幅および位相が既知であるパイロット信号から全信号帯域にわたる周波数特性を検出する。ＩＦＦＴ４５２では周波数特性検出部４５１で求めた周波数を逆フーリエ変換し遅延プロファイルを求めている。親局直接波変動量推定部４５３では遅延プロファイルｆ（ｔ）のｔ＝０の時点の信号を抽出している。抽出した信号は親局波成分（希望波成分）に相当する。ＦＦＴ４５５では抽出された親局波成分のＦＦＴをおこなう。誤差信号算出部４５６では周波数特性検出部４５１で求めた周波数特性から、ＦＦＴ４５５から出力される希望波成分を取り除き、親局マルチパスや回り込み成分だけの周波数特性を誤差信号として算出する。
【００１９】
Ｄ／Ｕ演算部４５４では受信信号の遅延プロファイルと遅延プロファイルから抽出された希望波成分から入力のＤ／Ｕを求めている。すなわち、希望波成分の電力を遅延プロファイルの全電力から希望波成分の電力を減算したもので割算する。
【００２０】
誤差信号算出部では以上のように受信信号の遅延プロファイルの算出を行っているために、容易に受信信号のＤ／Ｕを求めることができる。
【００２１】
つぎに出力Ｄ／Ｕ検知回路５の内部処理回路について説明する。図１で、５０１、５０３は受信信号及び送信信号の平均電力値を求める平均電力部であり、５０２は出力Ｄ／Ｕ演算部であり、５０４は判定回路である。
図１では、平均電力部５０１が受信信号入力部に相当し、平均電力部５０３が送信信号入力部に相当し、出力Ｄ／Ｕ演算部５０２は受信信号希望波不要波比入力部及び送信信号希望波不要波比算出部に相当し、判定回路５０４が判定部に相当する。
【００２２】
出力Ｄ／Ｕ演算部５０２は、Ａ／Ｄコンバータ４０２でデジタル信号に変換された受信信号を平均電力部５０１で電力に変換し平均化した受信信号の平均電力値（Ｐｉｎ）と、直交変調器４１０から出力される信号を平均電力部５０３で電力に変換し平均化した送信信号の平均電力値（Ｐｏｕｔ）と、誤差信号出力部４０６より出力される受信信号のＤ／Ｕを用いて出力Ｄ／Ｕを求める演算を行う。
【００２３】
出力Ｄ／Ｕ演算部５０２の演算について説明する。
受信信号の平均電力値Ｐｉｎは受信信号に含まれる親局波成分の電力（ＰＤ）と親局マルチパスと回り込み波成分の電力（ＰＵｉｎ）の和である。Ｐｉｎ＝ＰＤ＋ＰＵｉｎ。
送信信号の平均電力値Ｐｏｕｔは送信信号に含まれる親局波成分の電力（ＰＤ）と送信信号に含まれるキャンセラにより除去の出来なかった親局マルチパスと回り込み波成分の電力（ＰＵｏｕｔ）の和である。Ｐｏｕｔ＝ＰＤ＋ＰＵｏｕｔ。
入力Ｄ／Ｕとは受信信号に含まれる親局波成分の電力（ＰＤ）と親局マルチパスと回り込み波成分の電力（ＰＵｉｎ）の比である。入力Ｄ／Ｕ＝ＰＤ／ＰＵｉｎ。
これらの関係より、送信信号に含まれる親局波成分の電力（ＰＤ）と送信信号に含まれるキャンセラにより除去の出来なかった親局マルチパスと回り込み波成分の電力（ＰＵｏｕｔ）の比である出力Ｄ／Ｕは次の式で求められる。
【００２４】
【数１】

【００２５】
判定回路５０４では出力Ｄ／Ｕ演算部５０２で求めた出力Ｄ／Ｕをある閾値と比較し回り込みキャンセラ４における不要波成分キャンセル処理が適切なレベルで行われているか否かを判定し、判定結果を出力する。この判定結果を用いて、キャンセラ装置からＤ／Ｕ劣化のアラームをだす。
【００２６】
このように、本実施の形態によれば、入力信号電力、出力信号電力及び受信信号のＤ／Ｕを用いることにより送信信号のＤ／Ｕを容易に算出することができる。
そして、Ｄ／Ｕの検知専用にＦＦＴ、ＩＦＦＴなどの大規模な演算回路を用いないため、装置が安価にできる効果があり、また、アナログ部に専用の検知回路を付け足すよりも容易である。
【００２７】
実施の形態２．
図３に、実施の形態２に係るデジタル信号処理型回り込みキャンセラを含む中継局の構成例を示す。
【００２８】
図３において、９は異常検出回路である。なお、前述した実施の形態１と同様の構成については、同一の符号を付してその説明を省略する。異常検出回路９は、管理装置の例に相当する。
【００２９】
実施の形態１では、回り込みキャンセラ４の入力信号電力と、出力信号電力と入力Ｄ／Ｕとを用いて出力Ｄ／Ｕを演算した。これに対して、実施の形態２では、回り込みキャンセラ４の入力電力（Ｐｉｎ）と誤差信号出力部４０６で求める入力Ｄ／Ｕを用いて出力電力推定部５０５で回り込みキャンセラ４の出力電力（Ｐｏｕｔ）を推定し、この推定値と実際の出力信号電力とを判定回路５０６により比較し、この比較結果を用いて回り込みキャンセラの動作良否判定を行う。
【００３０】
図３において、５０５は出力電力推定部であり、５０６は判定回路である。出力電力推定部５０５は、受信信号希望波不要波比算出部及び電力値算出部に相当する。
出力電力推定部５０５では平均電力部５０１から出力される回り込みキャンセラの入力電力（Ｐｉｎ）と誤差信号出力部４０６で算出される入力Ｄ／Ｕを用いて、受信信号から親局マルチパス波と回り込み波成分が回り込みキャンセラによって完全に除去されたときの回り込みキャンセラの出力（Ｐｏｕｔ）を算出する。
【００３１】
受信信号から親局マルチパス波と回り込み波成分が回り込みキャンセラによって完全に除去されたとすれば、回り込みキャンセラの出力（Ｐｏｕｔ）はすなわち受信信号の親局波成分（受信信号希望波成分電力値）と一致する。この関係より受信信号から親局マルチパス波と回り込み波成分が回り込みキャンセラによって完全に除去された時の出力電力（＝受信信号中の希望波成分の電力）は以下の数２に示す式で表される。この演算を出力電力推定部５０５で行う。
【００３２】
【数２】

【００３３】
この出力電力推定部５０５で演算される推定値と、平均電力部５０３で演算される実際のキャンセラ出力電力を比較し、両者の差がある範囲以内ならば回り込みキャンセラ４は正常に動作しているとする。この判定結果を用いてキャンセラ装置の異常を検知し回り込みキャンセラからアラームを出力する。
【００３４】
ここで、実施の形態１、２で説明した出力Ｄ／Ｕ検知方法及び回り込みキャンセラの動作良否判定方法の特徴を、以下にて再言する。
【００３５】
実施の形態１に示した回り込みキャンセラの出力Ｄ／Ｕ検知方法は、ＯＦＤＭ信号の中継局で同一周波数中継を行う際に用いられる回り込みキャンセラにおいて、回り込みキャンセラの入力電力、出力電力、入力Ｄ／Ｕから出力Ｄ／Ｕを算出することを特徴とする。
【００３６】
実施の形態２に示した回り込みキャンセラの動作良否判定方法は、ＯＦＤＭ信号の中継局で同一周波数中継を行う際に用いられる回り込みキャンセラにおいて、回り込みキャンセラの入力電力、入力Ｄ／Ｕから出力電力を推定し、実際の出力電力と比較することを特徴とする。
【００３７】
【発明の効果】
以上のように、本発明によればキャンセラ装置から入力される受信信号、送信信号、受信信号希望波不要波比に基づき、送信信号希望波不要波比及び受信信号希望波成分電力値を算出できるため、ＦＦＴやＩＦＦＴなどの特別な装置を不要とし、装置構成を簡単化し製造コストの低減を図ることができる。
【図面の簡単な説明】
【図１】実施の形態１に係る中継局の構成例を示す図である。
【図２】回り込みキャンセラの構成例を示す図である。
【図３】実施の形態２に係る中継局の構成例を示す図である。
【符号の説明】
１中継局受信アンテナ、２フロントエンド、３ダウンコンバータ、４回り込みキャンセラ、５出力Ｄ／Ｕ検知回路、６アップコンバータ、７電力増幅部、８送信アンテナ、９異常検出回路、４０１周波数変換器、４１２周波数変換器、４０２Ａ／Ｄコンバータ（アナログ／デジタル変換器）、４０３直交検波器、４０４ＦＦＴ（高速フーリエ変換器）、４０５パイロット信号抽出部、４０６誤差信号出力部、４０７ＩＦＦＴ（逆高速フーリエ変換器）、４０８レプリカ生成器、４０９減算器、４１０直交変調器、４１１Ｄ／Ａコンバータ（デジタル／アナログ変換器）、４５１周波数特性検出部、４５２ＩＦＦＴ、４５３親局直接波変動量推定部、４５４Ｄ／Ｕ演算部、４５５ＦＦＴ、４５６誤差信号算出部、５０１平均電力部、５０３平均電力部、５０２出力Ｄ／Ｕ演算部、５０４判定回路、５０５出力電力推定部、５０６判定回路。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to detection of an output D / U (desired wave unnecessary wave ratio) of a loop canceller used for, for example, SFN (Single Frequency Network) relay of terrestrial digital broadcasting.
[0002]
[Prior art]
In digital terrestrial broadcasting, studies are being made to apply a loop canceller to a relay station to realize a single frequency network. Since the transmission signal frequency and the reception signal frequency are the same in the relay in the single frequency network, the radio wave transmitted from the transmission antenna may wrap around the reception signal and cause oscillation. As a method of preventing the oscillation, a method of increasing the physical distance between the transmitting antenna and the receiving antenna, and a method of removing a loop wave from a transmission signal using a loop canceller are considered.
[0003]
In addition, the signal received by the relay station includes a delayed wave (master station multipath wave) that is reflected and arrives at mountains or the sea in addition to a direct wave. A loop canceller is a device that removes a loop wave component and a master station multipath wave component included in a received signal, and it is necessary to monitor the state of removal in a transmission signal.
A desired wave unnecessary wave ratio (hereinafter, “D / U”) is an index for monitoring. The desired wave having the desired wave unnecessary wave ratio is a master station signal, and the unnecessary waves are a master station multipath and a loopback wave. The desired wave unnecessary wave ratio is a ratio of a desired wave component and an unnecessary wave component included in a signal. Monitoring D / U is important as an item for monitoring the output signal of the wraparound canceller device. Conventionally, for example, as shown in Japanese Patent Application Laid-Open No. 2001-60924, a D / U detection circuit has been configured by an analog circuit.
[0004]
[Patent Document 1]
JP-A-2001-60924 [0005]
[Problems to be solved by the invention]
Since the conventional D / U detection circuit is configured by an analog circuit as described above, in order to apply the output D / U detection of the wraparound canceller using digital signal processing, the output of the canceller is controlled by a sweep oscillator or the like. A dedicated circuit to be configured must be configured, and there has been a problem that the device is increased in size.
[0006]
As a D / U detection method in digital signal processing, there is a method of detecting D / U from a delay profile. However, there is a problem that an operation such as FFT and IFFT is required, and the circuit becomes large-scale.
[0007]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its main object to easily detect, for example, the output D / U of a digital signal processing type wraparound canceller.
[0008]
[Means for Solving the Problems]
The management device according to the present invention,
A signal containing an undesired wave component other than the desired wave component and the desired wave component is received from the outside as a received signal, and an unnecessary wave component canceling process for removing the unnecessary wave component from the received signal is performed. A management unit that transmits a signal to the outside as a transmission signal and is connected to a canceller device that calculates a ratio between a desired wave component and an unnecessary wave component in a reception signal as a reception signal desired wave unnecessary wave ratio, and manages the canceller device. A device,
A reception signal input unit for inputting a reception signal from the canceller device,
A transmission signal input unit for inputting a transmission signal from the canceller device,
A reception signal desired wave unnecessary wave ratio input unit for inputting a reception signal desired wave unnecessary wave ratio from the canceller device,
Based on the received signal, the transmitted signal, and the desired signal unwanted wave ratio, the ratio between the desired wave component in the transmitted signal and the unwanted wave component that could not be removed by the unnecessary wave component canceling process of the canceller apparatus is used to determine whether the transmitted signal desired wave is unnecessary. And a transmission signal desired wave unnecessary wave ratio calculation unit for calculating as a wave ratio.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
FIG. 1 shows a configuration example of a relay station using a loop canceller for digital terrestrial broadcasting using the same frequency relay.
1 is a relay station receiving antenna for receiving a master station wave for relaying, 2 is a front end composed of a reception filter, etc., 3 is a down converter that performs frequency conversion from a radio frequency band to an intermediate frequency band, and 4 is a received signal. Canceler (canceller device) for performing unnecessary wave component canceling processing for removing the components of the wraparound wave and the component of the master station multipath included in, and detecting the input D / U, and 5 is an output for monitoring and managing the wraparound canceller 4 A D / U detection circuit (management device), 6 is an up-converter for performing frequency conversion from an intermediate frequency band to a radio frequency band, 7 is a power amplifier, and 8 is a transmission antenna.
Here, the input D / U is the D / U of the received signal received by the relay station receiving antenna 1 and corresponds to the desired signal unnecessary wave ratio, and the output D / U is This is the D / U of the transmission signal to be transmitted, and corresponds to the transmission signal desired wave unnecessary wave ratio.
[0010]
An RF (Radio Frequency) signal received by the relay station receiving antenna 1 is converted into an IF (INTERMEDIATE FREQUENCY) signal via a front end 2 and a down converter 3. The received signal converted into an IF signal by the down converter 3 is subjected to removal of a loop wave and a master station multipath by the loop canceller 4. The signal from which the loop-back wave and the master station multipath have been removed by the loop-back canceller 4 is converted into an RF signal by the up-converter 6. The signal converted into the RF signal is amplified by the power amplifier 7 and transmitted from the transmission antenna 8.
[0011]
The internal processing circuit of the wraparound canceller 4 will be described.
In FIG. 1, 401 and 412 are frequency converters, 402 is an A / D (analog / digital) converter, 403 is a quadrature detector, 404 is an FFT (fast Fourier transformer), and 405 is a pilot. Reference numeral 406 denotes an error signal output unit, 407 denotes an IFFT (Inverse Fast Fourier Transformer), 408 denotes a replica generator, 409 denotes a subtractor, and 410 denotes a quadrature modulator. Reference numeral 411 denotes a D / A (digital / analog) converter.
[0012]
The signal converted into an IF signal by the down converter 3 is further frequency-converted to a lower signal by the frequency converter 401, and is converted to a digital signal by the A / D converter 402. The signal converted to a digital signal by the A / D converter 402 is subjected to quadrature detection by the quadrature detector 403, and becomes a baseband signal.
[0013]
The baseband signal output by the quadrature detector 403 is subjected to FFT processing by an FFT 404, and is converted from a time domain signal to a frequency domain signal. Pilot signal extraction section 405 extracts a pilot signal having a known amplitude and phase inserted at a predetermined position in the frequency axis direction from a signal in the frequency domain output from FFT 404.
[0014]
The error signal output unit 406 calculates an error signal having frequency characteristics of a multipath wave or a loop wave component of the master station transmission signal based on the extracted pilot signal. The error signal obtained by error signal output section 406 is converted from a frequency domain signal to a time domain signal by IFFT 407, and a transmission path including multipath and roundabout amplitude and phase of the base station transmission signal and delay time information. It is sent to replica generator 408 as an estimate. The replica generator 408 generates a replica signal of the master station multipath and the wraparound wave from the transmission channel estimation value from the IFFT 407 and the output signal of the subtractor 409.
[0015]
The subtractor 409 subtracts the received signal from the quadrature detector 403 and the replica signal from the replica generator 408. By this subtraction, the master station multipath wave and the loop wave component are removed from the received signal (unnecessary wave component cancellation processing).
[0016]
The signal from which the master station multipath wave and the wraparound wave component have been removed by the subtractor 409 is quadrature-modulated by the quadrature modulator 410. The signal orthogonally modulated by the orthogonal modulator 410 is converted from a digital signal to an analog signal by the D / A converter 411. The signal converted to an analog signal by the D / A converter 411 is converted to an IF signal by a frequency converter.
[0017]
The error signal output unit 406 will be described. FIG. 2 is a diagram showing a configuration of the error signal output unit 406. 2, reference numeral 451 denotes a frequency characteristic detecting unit, 452 denotes an IFFT, 453 denotes a master station direct wave fluctuation amount estimating unit, 454 denotes a D / U calculation unit, 455 denotes an FFT, and 456 denotes a FFT. It is an error signal calculator.
[0018]
In the error signal output unit 406, the frequency characteristic detection unit 451 detects a frequency characteristic over the entire signal band from a pilot signal whose amplitude and phase are known. The IFFT 452 obtains a delay profile by performing an inverse Fourier transform on the frequency obtained by the frequency characteristic detection unit 451. The master station direct wave fluctuation estimation unit 453 extracts the signal at the time point t = 0 in the delay profile f (t). The extracted signal corresponds to a master station wave component (a desired wave component). In the FFT 455, an FFT of the extracted parent station wave component is performed. The error signal calculation unit 456 removes the desired wave component output from the FFT 455 from the frequency characteristics obtained by the frequency characteristic detection unit 451, and calculates the frequency characteristics of only the master station multipath and the wraparound component as an error signal.
[0019]
The D / U calculation unit 454 obtains the input D / U from the delay profile of the received signal and the desired wave component extracted from the delay profile. That is, the power of the desired wave component is divided by the value obtained by subtracting the power of the desired wave component from the total power of the delay profile.
[0020]
Since the error signal calculator calculates the delay profile of the received signal as described above, the D / U of the received signal can be easily obtained.
[0021]
Next, an internal processing circuit of the output D / U detection circuit 5 will be described. In FIG. 1,

reference numerals

501 and 503 denote an average power unit for calculating an average power value of a reception signal and a transmission signal, 502 denotes an output D / U operation unit, and 504 denotes a determination circuit.
In FIG. 1, the average power section 501 corresponds to the reception signal input section, the average power section 503 corresponds to the transmission signal input section, and the output D / U calculation section 502 includes the reception signal desired wave unnecessary wave ratio input section and the transmission signal. The determination circuit 504 corresponds to the desired wave unnecessary wave ratio calculation unit, and the determination circuit 504 corresponds to the determination unit.
[0022]
The output D / U operation unit 502 converts the received signal converted to a digital signal by the A / D converter 402 into power by the average power unit 501 and averages the average power value (Pin) of the received signal, and a quadrature modulator. The output signal is output using the average power value (Pout) of the transmission signal obtained by converting the signal output from the signal 410 into power by the average power unit 503 and averaging, and the D / U of the reception signal output from the error signal output unit 406. / U is calculated.
[0023]
The operation of the output D / U operation unit 502 will be described.
The average power value Pin of the received signal is the sum of the power of the parent station wave component (PD) included in the received signal, the power of the parent station multipath, and the power of the wraparound wave component (PUin). Pin = PD + PUin.
The average power value Pout of the transmission signal is the sum of the power (PD) of the parent station wave component included in the transmission signal, the power of the master station multipath that cannot be removed by the canceller included in the transmission signal, and the power of the loopback wave component (PUout). It is. Pout = PD + PUout.
The input D / U is the ratio of the power of the parent station wave component (PD) included in the received signal to the power of the parent station multipath and the power of the loop wave component (PUin). Input D / U = PD / PUin.
From these relations, the output which is the ratio of the power of the parent station wave component (PD) included in the transmission signal to the power of the master station multipath that could not be removed by the canceller included in the transmission signal and the power of the loopback wave component (PUout). D / U is obtained by the following equation.
[0024]
(Equation 1)

[0025]
The determination circuit 504 compares the output D / U obtained by the output D / U calculation unit 502 with a certain threshold value to determine whether or not the unnecessary wave component cancellation processing in the wraparound canceller 4 is performed at an appropriate level. Is output. Using this determination result, an alarm of D / U deterioration is issued from the canceller device.
[0026]
As described above, according to the present embodiment, D / U of a transmission signal can be easily calculated by using D / U of an input signal power, an output signal power, and a reception signal.
In addition, since a large-scale arithmetic circuit such as FFT and IFFT is not used exclusively for D / U detection, there is an effect that the apparatus can be inexpensive, and it is easier than adding a dedicated detection circuit to the analog section.
[0027]
Embodiment 2 FIG.
FIG. 3 shows a configuration example of a relay station including a digital signal processing type wraparound canceller according to the second embodiment.
[0028]
In FIG. 3, reference numeral 9 denotes an abnormality detection circuit. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The abnormality detection circuit 9 corresponds to an example of a management device.
[0029]
In the first embodiment, the output D / U is calculated using the input signal power of the wraparound canceller 4, the output signal power, and the input D / U. On the other hand, in the second embodiment, the output power estimation unit 505 uses the input power (Pin) of the loop canceller 4 and the input D / U obtained by the error signal output unit 406 to output power (Pout) of the loop canceller 4. Is estimated, and the estimated value is compared with the actual output signal power by the determination circuit 506, and the quality of the operation of the loop canceller is determined using the comparison result.
[0030]
In FIG. 3, reference numeral 505 denotes an output power estimating unit, and 506 denotes a determination circuit. Output power estimating section 505 corresponds to a received signal desired wave unnecessary wave ratio calculating section and a power value calculating section.
The output power estimating section 505 uses the input power (Pin) of the loop canceller output from the average power section 501 and the input D / U calculated by the error signal output section 406 to wrap the received signal into a master station multipath wave. The output (Pout) of the wraparound canceller when the wave component is completely removed by the wraparound canceller is calculated.
[0031]
Assuming that the master station multipath wave and the wraparound wave component are completely removed from the received signal by the wraparound canceller, the output (Pout) of the wraparound canceller is, that is, the master station wave component (received signal desired wave component power value) of the received signal. Matches. From this relationship, the output power (= the power of the desired wave component in the received signal) when the master station multipath wave and the loop wave component are completely removed from the received signal by the loop canceller is expressed by the following equation (2). Is done. This calculation is performed by the output power estimation unit 505.
[0032]
(Equation 2)

[0033]
The estimated value calculated by the output power estimation unit 505 is compared with the actual canceller output power calculated by the average power unit 503. If the difference between the two is within a certain range, the wraparound canceller 4 operates normally. And Using this determination result, an abnormality of the canceller device is detected, and an alarm is output from the wraparound canceller.
[0034]
Here, the features of the output D / U detection method and the wraparound canceller operation determination method described in the first and second embodiments will be described again below.
[0035]
The output D / U detection method of the wraparound canceller described in the first embodiment is based on the wraparound canceller used when the same frequency relay is performed at the relay station of the OFDM signal, and the input power, output power, input D / U of the wraparound canceller are used. Is calculated from the output D / U.
[0036]
In the wraparound canceler used in performing the same frequency relay at the relay station of the OFDM signal, the method of judging whether or not the wraparound canceller operates as described in Embodiment 2 estimates the output power from the input power and the input D / U of the wraparound canceller. Then, the actual output power is compared with the actual output power.
[0037]
【The invention's effect】
As described above, according to the present invention, the transmission signal desired wave unnecessary wave ratio and the received signal desired wave component power value can be calculated based on the reception signal, the transmission signal, and the reception signal desired wave unnecessary wave ratio input from the canceller device. Therefore, a special device such as an FFT or an IFFT is not required, so that the device configuration can be simplified and the manufacturing cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration example of a relay station according to Embodiment 1.
FIG. 2 is a diagram illustrating a configuration example of a wraparound canceller.
FIG. 3 is a diagram showing a configuration example of a relay station according to a second embodiment.
[Explanation of symbols]
Reference Signs List 1 relay station receiving antenna, 2 front end, 3 down converter, 4 wraparound canceller, 5 output D / U detection circuit, 6 up converter, 7 power amplifier, 8 transmission antenna, 9 abnormality detection circuit, 401 frequency converter, 412 Frequency converter, 402 A / D converter (analog / digital converter), 403 quadrature detector, 404 FFT (fast Fourier transform), 405 pilot signal extraction unit, 406 error signal output unit, 407 IFFT (inverse fast Fourier transform) 408 replica generator, 409 subtractor, 410 quadrature modulator, 411 D / A converter (digital / analog converter), 451 frequency characteristic detector, 452 IFFT, 453 master station direct wave fluctuation estimation unit, 454 D / U operation unit, 455 FFT, 456 error signal calculation unit, 501 average Power unit, 503 average power unit, 502 output D / U operation unit, 504 determination circuit, 505 output power estimation unit, 506 determination circuit.

Claims

A signal containing an undesired wave component other than the desired wave component and the desired wave component is received from the outside as a received signal, and an unnecessary wave component canceling process for removing the unnecessary wave component from the received signal is performed. A management unit that transmits a signal to the outside as a transmission signal and is connected to a canceller device that calculates a ratio between a desired wave component and an unnecessary wave component in a reception signal as a reception signal desired wave unnecessary wave ratio, and manages the canceller device. A device,
A reception signal input unit for inputting a reception signal from the canceller device,
A transmission signal input unit for inputting a transmission signal from the canceller device,
A reception signal desired wave unnecessary wave ratio input unit for inputting a reception signal desired wave unnecessary wave ratio from the canceller device,
Based on the received signal, the transmitted signal, and the desired signal unwanted wave ratio, the ratio between the desired wave component in the transmitted signal and the unwanted wave component that could not be removed by the unnecessary wave component canceling process of the canceller apparatus is used to determine whether the transmitted signal desired wave is unnecessary. A management apparatus comprising: a transmission signal desired wave unnecessary wave ratio calculation unit that calculates a wave ratio.

The reception signal input unit,
Determine the average power value of the received signal input from the canceller device, and notify the average power value of the determined received signal to the transmission signal desired wave unnecessary wave ratio calculation unit,
The transmission signal input unit,
Determine the average power value of the transmission signal input from the canceller device, and notify the average power value of the determined transmission signal to the transmission signal desired wave unnecessary wave ratio calculation unit,
The transmission signal desired wave unnecessary wave ratio calculation unit,
2. The management apparatus according to claim 1, wherein the transmission signal desired wave unnecessary wave ratio is calculated based on the average power value of the reception signal, the average power value of the transmission signal, and the desired signal unnecessary wave ratio.

The management device further includes:
A determining unit that compares the desired ratio of the unnecessary wave of the transmission signal calculated by the desired signal unnecessary wave ratio calculation unit with a predetermined threshold value and determines whether the unnecessary wave component canceling process of the canceller apparatus is appropriate based on the comparison result; The management device according to claim 1, further comprising:

A signal containing an undesired wave component other than the desired wave component and the desired wave component is received from the outside as a received signal, and an unnecessary wave component canceling process for removing the unnecessary wave component from the received signal is performed. A management unit that transmits a signal to the outside as a transmission signal and is connected to a canceller device that calculates a ratio between a desired wave component and an unnecessary wave component in a reception signal as a reception signal desired wave unnecessary wave ratio, and manages the canceller device. A device,
A reception signal input unit for inputting a reception signal from the canceller device,
A transmission signal input unit for inputting a transmission signal from the canceller device,
A reception signal desired wave unnecessary wave ratio input unit for inputting a reception signal desired wave unnecessary wave ratio from the canceller device,
Based on the received signal and received signal desired wave unnecessary wave ratio, a power value calculation unit that calculates the power value of the desired wave component in the received signal as the received signal desired wave component power value,
Based on the received signal desired wave component power value calculated by the power value calculation unit and the transmission signal input by the transmission signal input unit, a determination unit that determines whether the unnecessary wave component cancellation processing of the canceller device is appropriate. A management device, comprising:

The reception signal input unit,
Determine the average power value of the received signal input from the canceller device, notify the average power value of the determined received signal to the power value calculation unit,
The power value calculation unit,
Based on the average power value of the received signal and the received signal desired wave unnecessary wave ratio, calculate the average power value of the desired wave component in the received signal as the received signal desired wave component power value,
The transmission signal input unit,
Determine the average power value of the transmission signal input from the canceller device, notify the average power value of the determined transmission signal to the determination unit,
The determination unit is
The received signal desired wave component power value calculated by the power value calculation unit is compared with the average power value of the transmission signal notified from the transmission signal input unit, and unnecessary wave component cancellation processing of the canceller device is performed based on the comparison result. The management device according to claim 4, wherein it is determined whether or not the management is appropriate.

The management device,
The management device according to claim 1, wherein the canceller device is connected to a wraparound canceller device used for SFN (Single Frequency Network) relay.

A signal containing an undesired wave component other than the desired wave component and the desired wave component is received from the outside as a received signal, and an unnecessary wave component canceling process for removing the unnecessary wave component from the received signal is performed. A management method for managing a canceller device that transmits a signal to the outside as a transmission signal and calculates a ratio between a desired wave component and an unnecessary wave component in a reception signal as a reception signal desired wave unnecessary wave ratio,
A reception signal inputting step of inputting a reception signal from the canceller device,
A transmission signal inputting step of inputting a transmission signal from the canceller device,
A received signal desired wave unnecessary wave ratio input step of inputting a received signal desired wave unnecessary wave ratio from the canceller device,
Based on the received signal, the transmitted signal, and the desired signal unwanted wave ratio, the ratio between the desired wave component in the transmitted signal and the unwanted wave component that could not be removed by the unnecessary wave component canceling process of the canceller apparatus is used to determine whether the transmitted signal desired wave is unnecessary. A transmission signal desired wave unnecessary wave ratio calculating step of calculating as a wave ratio.

A signal containing an undesired wave component other than the desired wave component and the desired wave component is received from the outside as a received signal, and an unnecessary wave component canceling process for removing the unnecessary wave component from the received signal is performed. A management method for managing a canceller device that transmits a signal to the outside as a transmission signal and calculates a ratio between a desired wave component and an unnecessary wave component in a reception signal as a reception signal desired wave unnecessary wave ratio,
A reception signal inputting step of inputting a reception signal from the canceller device,
A transmission signal inputting step of inputting a transmission signal from the canceller device,
A received signal desired wave unnecessary wave ratio input step of inputting a received signal desired wave unnecessary wave ratio from the canceller device,
A power value calculating step of calculating a power value of a desired wave component in the received signal as a received signal desired wave component power value based on the received signal and the received signal desired wave unnecessary wave ratio,
A determination step of determining whether the unnecessary wave component canceling process of the canceller apparatus is appropriate based on the received signal desired wave component power value calculated in the power value calculation step and the transmission signal input in the transmission signal input step. A management method characterized by having.