JPH07162360A - Fading variation estimator - Google Patents
Fading variation estimatorInfo
- Publication number
- JPH07162360A JPH07162360A JP34097493A JP34097493A JPH07162360A JP H07162360 A JPH07162360 A JP H07162360A JP 34097493 A JP34097493 A JP 34097493A JP 34097493 A JP34097493 A JP 34097493A JP H07162360 A JPH07162360 A JP H07162360A
- Authority
- JP
- Japan
- Prior art keywords
- correlator
- output
- signal
- impulse response
- fluctuation amount
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はディジタル移動体通信に
おけるフェージング変動量推定器、さらに詳しくは移動
無線受信機における伝送路の高速変動によるフェージン
グ変動量を推定するフェージング変動量推定器に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fading fluctuation estimator in digital mobile communication, and more particularly to a fading fluctuation estimator for estimating fading fluctuation due to high speed fluctuation of a transmission line in a mobile radio receiver.
【０００２】[0002]
【従来の技術】移動無線機における無線通信において
は、移動体通信特有の送受信間の伝送路長の変動による
フェージング(fading)が生じる。従って受信側において
アダプティブ・イコライザ(equalizer) 等のフェージン
グ補償装置を用いてこれを補償するのが一般的である。
然しながら移動体は一般的にたえずその移動速度が変動
するので、これによって起こるフェージング変動量を推
定し、これを補償する必要がある。2. Description of the Related Art In wireless communication in a mobile wireless device, fading occurs due to fluctuations in the transmission path length between transmission and reception, which is unique to mobile communication. Therefore, it is general to compensate for this by using a fading compensation device such as an adaptive equalizer on the receiving side.
However, since the moving speed of a moving body generally constantly fluctuates, it is necessary to estimate the amount of fading fluctuation caused by this and compensate for it.
【０００３】受信側でこのフェージング変動量を推定し
ようとする場合、一つの方法としては受信信号に対しＦ
ＦＴ(fast Fourier transformation) を実行する方法が
あるが、この方法は演算が複雑で回路規模が大きくなっ
てしまうという欠点がある。また、自動車無線などでは
移動体の移動速度を検出できるため、検出した移動速度
によってフェージング変動量を推定する方法があるが、
通常の携帯型移動無線機では移動速度を検出できず、ま
た、自動車無線であっても送信側も移動しているような
場合には送信側の移動速度も同時に検出しなければ変動
量の推定ができない。したがって、従来ではアダプティ
ブ・イコライザ等のフェージング補償装置を用いる場合
には、想定される最大のフェージング変動量が常に生じ
ているという仮定で動作させている。When trying to estimate this fading fluctuation amount on the receiving side, one method is to use F for the received signal.
Although there is a method of performing FT (fast Fourier transformation), this method has a drawback that the calculation is complicated and the circuit scale becomes large. In addition, since the moving speed of a moving object can be detected in automobile radio, etc., there is a method of estimating the fading fluctuation amount based on the detected moving speed.
Ordinary portable mobile radios cannot detect the moving speed, and even if the transmitting side is moving even in automobile radio, the moving speed of the transmitting side must be detected at the same time to estimate the amount of fluctuation. I can't. Therefore, conventionally, when a fading compensation device such as an adaptive equalizer is used, it is operated on the assumption that the maximum possible fading fluctuation amount always occurs.
【０００４】[0004]
【発明が解決しようとする課題】上記のように従来では
ディジタル移動体無線通信における受信側で、移動体の
移動速度の変動によって起こるフェージング変動量を容
易に推定する適当な手段がなく、アダプティブ・イコラ
イザ等のフェージング補償装置を用いる場合に、想定さ
れる最大のフェージング変動量が常に生じているという
仮定で動作させており、このため実際の変動量とことな
る場合、ビット誤り率などの特性が劣化してしまうとい
う問題点があった。As described above, in the conventional art, there is no suitable means for easily estimating the fading fluctuation amount caused by the fluctuation of the moving speed of the moving body at the receiving side in the digital mobile radio communication, and the adaptive When using a fading compensation device such as an equalizer, it is operated on the assumption that the maximum expected fading fluctuation amount is always occurring.Therefore, if it is different from the actual fluctuation amount, characteristics such as bit error rate are There was a problem of deterioration.
【０００５】本発明はかかる問題点を解決するためにな
されたものであり、受信側で逐次フェージング変動量を
推定できる簡易な回路構成のフェージング変動量推定器
を提供することを目的としている。The present invention has been made to solve the above problems, and an object of the present invention is to provide a fading fluctuation amount estimator having a simple circuit configuration capable of successively estimating the fading fluctuation amount on the receiving side.
【０００６】[0006]
【課題を解決するための手段】本発明に係わるフェージ
ング変動量推定器は、送信側では予め定められたパター
ンの既知信号を定期的に送信信号に挿入して送信する手
段、受信側では上記既知信号と実質的に同一の参照信号
を用いて相関演算を行い上記既知信号の幅により伝送路
のインパルス応答特性を推定する手段、上記手段により
推定される現時点の伝送路のインパルス応答特性とこれ
より以前のインパルス応答特性との相関演算を行い、イ
ンパルス応答特性の時間的変動量を得、これにより移動
体の移動速度の変動によって起こるフェージング変動量
を推定する手段を備えたことを特徴とする。A fading fluctuation amount estimator according to the present invention is a means for transmitting a signal by periodically inserting a known signal having a predetermined pattern into a transmission signal on the transmitting side and the known signal on the receiving side. Means for estimating the impulse response characteristic of the transmission line by the width of the known signal by performing a correlation operation using a reference signal substantially the same as the signal, and the impulse response characteristic of the current transmission channel estimated by the means The present invention is characterized in that a means for estimating the fading fluctuation amount caused by the fluctuation of the moving speed of the moving body by performing the correlation calculation with the previous impulse response characteristic to obtain the temporal fluctuation amount of the impulse response characteristic.
【０００７】[0007]
【作用】本発明のフェージング変動量推定器において
は、比較的簡易な回路規模により、外部からの移動速度
に関する情報を必要とすることなく、受信信号からフェ
ージング変動量を推定することが可能となる。In the fading fluctuation amount estimator of the present invention, the fading fluctuation amount can be estimated from the received signal without the need for information on the moving speed from the outside due to the relatively simple circuit scale. .
【０００８】[0008]
【実施例】以下、本発明の実施例を図面を用いて説明す
る。図１は、本発明におけるフェージング変動量推定器
の一実施例を示すブロック図であり、図において、１は
第１の相関器、２は第２の相関器、３はメモリ、４はＬ
ＰＦ、５は変動量推定器である。図２は、本発明におけ
る信号形態を説明するための図である。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a fading fluctuation amount estimator according to the present invention. In the figure, 1 is a first correlator, 2 is a second correlator, 3 is a memory, and 4 is L.
PF and 5 are fluctuation amount estimators. FIG. 2 is a diagram for explaining a signal form in the present invention.
【０００９】図２に示すように、送信側では既知信号を
定期的に送信信号に挿入して送信する。この既知信号は
自己相関性の非常に鋭い、送受信側双方で予め定められ
たパターンの信号が用いられ、且つ、送信信号に比べ十
分に小さな割合で挿入され、既知信号の間隔も送信信号
の間隔に比べ十分に短いものとする。受信側では先ず相
関器１の一方の入力に図２に示す既知信号が挿入された
受信信号が入力され、もう一方の入力にこの既知信号と
同じパターンの参照信号が入力され、両者の間の相関関
係が演算され出力される。上述のように挿入される既知
信号およびこれと同じパターンの参照信号には、自己相
関性の鋭い信号が用いられているため、受信入力信号の
うち既知信号が挿入された部分で相関出力の絶対値は非
常に大きくなるが、受信入力信号のうち本来の送信信号
の部分では相関出力は小さな値となる。また、送信信号
が伝送路特性により歪むような場合には、これに応じて
既知信号部分にも歪みが生じ、従って相関器１の相関出
力はこの歪みに応じて時間的に拡がった波形となり、こ
れによりこの時点の伝送路のインパルス応答特性を推定
できる。As shown in FIG. 2, the transmitting side periodically inserts a known signal into the transmission signal and transmits it. This known signal has a very sharp autocorrelation, and a signal of a predetermined pattern is used on both the transmitting and receiving sides, and is inserted at a sufficiently smaller ratio than the transmission signal. It should be sufficiently shorter than. On the receiving side, first, the received signal in which the known signal shown in FIG. 2 is inserted is input to one input of the correlator 1, and the reference signal of the same pattern as this known signal is input to the other input, and The correlation is calculated and output. As the known signal inserted as described above and the reference signal having the same pattern as this, a signal with a sharp autocorrelation is used, and therefore the absolute value of the correlation output in the portion of the received input signal where the known signal is inserted. Although the value becomes very large, the correlation output becomes a small value in the part of the original transmission signal of the reception input signal. Further, when the transmission signal is distorted due to the transmission path characteristics, the known signal portion is distorted accordingly, and therefore the correlation output of the correlator 1 becomes a waveform that spreads in time according to this distortion, This makes it possible to estimate the impulse response characteristic of the transmission line at this point.
【００１０】この相関器１の出力はメモリ３へ一時記憶
され、相関器２で次の相関器１からの出力との相関関係
が演算され出力される。すなわち相関器２の出力から
は、相関器１から入力される現時点の伝送路のインパル
ス応答特性と、メモリ３から入力される一つ前の既知信
号に基づくインパルス応答特性との相関出力が得られ
る。従って、移動体の移動速度の変動によるフェージン
グ変動が無い場合や非常に小さい場合には、両者のイン
パルス応答特性の変動は無く、あるいは非常に小さくな
り、相関器２の出力の絶対値は大きな値となる。また逆
に移動体の移動速度の変動によるフェージング変動が大
きい場合には、相関器２の出力の絶対値は小さな値とな
る。すなわち、相関器２の出力により移動体の移動速度
の変動によるフェージング変動量を推定できるようにな
る。The output of the correlator 1 is temporarily stored in the memory 3, and the correlator 2 calculates and outputs the correlation with the output from the next correlator 1. That is, from the output of the correlator 2, the correlation output of the impulse response characteristic of the current transmission path input from the correlator 1 and the impulse response characteristic based on the previous known signal input from the memory 3 is obtained. . Therefore, when there is no fading fluctuation due to the fluctuation of the moving speed of the moving body or when it is very small, the impulse response characteristics of both do not fluctuate or become very small, and the absolute value of the output of the correlator 2 is a large value. Becomes On the contrary, when the fading fluctuation due to the fluctuation of the moving speed of the moving body is large, the absolute value of the output of the correlator 2 becomes a small value. That is, the output of the correlator 2 makes it possible to estimate the fading fluctuation amount due to the fluctuation of the moving speed of the moving body.
【００１１】この相関器２の出力はＬＦＰ４へ入力され
平滑化されてバラツキが吸収され、変動量推定器５へ入
力される。変動量推定器５は、この出力を利用する後段
の回路によりその構成を異にする。すなわち、アダプテ
ィブ・イコライザ等の追従特性を決定するのに用いる場
合には、相関値から変動量をパラメータそのものとして
出力する構成となるが、ドプラー周波数あるいはフェー
ジングピッチ等で出力したい場合には、受信入力値，搬
送波周波数，移動体の移動速度，既知信号の挿入間隔な
どを考慮した周波数変換を行う構成となる。The output of the correlator 2 is input to the LFP 4, smoothed to absorb variations, and then input to the fluctuation amount estimator 5. The fluctuation amount estimator 5 has a different configuration depending on the circuit in the subsequent stage that uses this output. That is, when it is used to determine the tracking characteristic of an adaptive equalizer, etc., the amount of fluctuation is output from the correlation value as the parameter itself, but if you want to output at the Doppler frequency or fading pitch, etc. The configuration is such that frequency conversion is performed in consideration of values, carrier frequencies, moving speeds of moving objects, and known signal insertion intervals.
【００１２】なお、上述の実施例では、移動体の移動速
度の変動によるフェージング変動量を推定する場合につ
いて述べたが、何れかの原因で伝送路長が高速に而も不
規則に変動する場合のフェージング変動量の推定の全て
に実施できることは言うまでもない。In the above embodiment, the case of estimating the fading fluctuation amount due to the fluctuation of the moving speed of the moving body has been described. However, when the transmission path length fluctuates at high speed and irregularly due to any cause. Needless to say, it can be performed for all the estimation of the fading fluctuation amount of.
【００１３】[0013]
【発明の効果】以上説明したように、本発明のフェージ
ング変動量推定器は、簡易な回路により受信信号から移
動体の移動速度の変動によるフェージング変動量を推定
することができる。さらに、本発明のフェージング変動
量推定器の出力をイコライザ等のフェージング補償装置
の制御に用いることにより、フェージング変動量に応じ
て最適なビット誤り率等の特性が得られる受信機が構成
できる等の効果がある。As described above, the fading fluctuation amount estimator of the present invention can estimate the fading fluctuation amount due to the fluctuation of the moving speed of the moving body from the received signal by a simple circuit. Furthermore, by using the output of the fading fluctuation estimator of the present invention to control a fading compensation device such as an equalizer, a receiver that can obtain characteristics such as an optimum bit error rate according to the fading fluctuation can be configured. effective.
【図１】本発明の一実施例を示すブロック図である。FIG. 1 is a block diagram showing an embodiment of the present invention.
【図２】本発明の信号形態を説明するための図である。FIG. 2 is a diagram for explaining a signal form of the present invention.
１ 第１の相関器 ２ 第２の相関器 ３ メモリ ４ ＬＰＦ ５ 変動量推定器 1 First Correlator 2 Second Correlator 3 Memory 4 LPF 5 Fluctuation Estimator
Claims (5)
変動で生じるフェージング変動量を推定するフェージン
グ変動量推定器において、 送信側では予め定められたパターンの既知信号を定期的
に送信信号に挿入して送信する手段、 受信側では上記既知信号と実質的に同一の参照信号を用
いて相関演算を行い上記既知信号の位置（幅）により伝
送路のインパルス応答特性を推定する手段、 上記手段により推定される現時点の伝送路のインパルス
応答特性とこれより以前のインパルス応答特性との相関
演算を行い、インパルス応答特性の時間的変動量を得、
これにより伝送路長の変動によるフェージング変動量を
推定する手段、 を備えたことを特徴とするフェージング変動量推定器。1. A fading fluctuation amount estimator for estimating a fading fluctuation amount caused by fluctuations in the moving speed of a mobile object in mobile communication, wherein a known signal having a predetermined pattern is periodically inserted into a transmission signal at a transmitting side. And a means for transmitting, and a means for estimating the impulse response characteristic of the transmission line from the position (width) of the known signal by performing a correlation calculation using the reference signal substantially the same as the known signal on the receiving side. The estimated impulse response characteristics of the transmission line and the earlier impulse response characteristics are correlated to obtain the temporal variation of the impulse response characteristics.
A fading fluctuation amount estimator comprising: means for estimating a fading fluctuation amount due to fluctuations in the transmission path length.
信号を入力し他の一方の入力端から上記参照信号を入力
し、両信号の相関関係を演算し出力する第１の相関器
と、 この第１の相関器の出力を一時的に記憶するメモリと、 一方の入力端から上記第１の相関器の出力を入力し他の
一方の入力端から上記メモリの記憶内容を入力して、現
時点の上記第１の相関器の出力とこれより以前の上記第
１の相関器の出力との相関関係を演算し出力する第２の
相関器とを備えたことを特徴とする請求項第１項記載の
フェージング変動量推定器。2. A first correlator that receives a received signal from one input terminal and inputs the reference signal from the other one input terminal, and calculates and outputs a correlation between the two signals. And a memory for temporarily storing the output of the first correlator, and an input of the output of the first correlator from one input end and a stored content of the memory from the other input end. And a second correlator that calculates and outputs a correlation between the output of the first correlator at this time point and the output of the first correlator earlier than this. The fading fluctuation amount estimator according to the first item.
たことを特徴とする請求項第２項記載のフェージング変
動量推定器。3. The fading fluctuation amount estimator according to claim 2, further comprising an LPF at a stage subsequent to the second correlator.
ＰＦを介した上記第２の相関器の出力をパラメータとし
て出力する手段を備えたことを特徴とする請求項第２項
または第３項記載のフェージング変動量推定器。4. The output of the second correlator or the L
4. A fading fluctuation amount estimator according to claim 2 or 3, further comprising means for outputting the output of the second correlator via a PF as a parameter.
ＰＦを介した上記第２の相関器の出力を所望の周波数で
出力するために、受信入力値，搬送波周波数の値，移動
体の移動速度，上記既知信号の挿入間隔等をパラメータ
として入力して周波数変換を行う手段を備えたことを特
徴とする請求項第２項または第３項記載のフェージング
変動量推定器。5. The output of the second correlator or the L
In order to output the output of the second correlator via the PF at a desired frequency, the received input value, the value of the carrier frequency, the moving speed of the moving body, the insertion interval of the known signal, etc. are input as parameters. The fading fluctuation estimator according to claim 2 or 3, further comprising means for performing frequency conversion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34097493A JPH07162360A (en) | 1993-12-10 | 1993-12-10 | Fading variation estimator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34097493A JPH07162360A (en) | 1993-12-10 | 1993-12-10 | Fading variation estimator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07162360A true JPH07162360A (en) | 1995-06-23 |
Family
ID=18342036
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP34097493A Pending JPH07162360A (en) | 1993-12-10 | 1993-12-10 | Fading variation estimator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07162360A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004068749A1 (en) * | 2003-01-30 | 2004-08-12 | Fujitsu Limited | Fading frequency estimation apparatus |
| US6931244B2 (en) | 2000-07-27 | 2005-08-16 | Sanyo Electric Co., Ltd. | Radio equipment capable of real time change of antenna directivity and doppler frequency estimating circuit used for the radio equipment |
| US7929592B1 (en) | 1999-04-02 | 2011-04-19 | Ntt Docomo, Inc. | Channel estimation device and method, demodulation device and method, and fading frequency decision device and method |
| JP2012004737A (en) * | 2010-06-15 | 2012-01-05 | Nec Corp | Radio base station device, mobile communication system, communication method thereof and program |
-
1993
- 1993-12-10 JP JP34097493A patent/JPH07162360A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7929592B1 (en) | 1999-04-02 | 2011-04-19 | Ntt Docomo, Inc. | Channel estimation device and method, demodulation device and method, and fading frequency decision device and method |
| US8295332B2 (en) | 1999-04-02 | 2012-10-23 | Ntt Docomo, Inc. | Channel estimation device and method, demodulation device and method, and fading frequency decision device and method |
| US6931244B2 (en) | 2000-07-27 | 2005-08-16 | Sanyo Electric Co., Ltd. | Radio equipment capable of real time change of antenna directivity and doppler frequency estimating circuit used for the radio equipment |
| WO2004068749A1 (en) * | 2003-01-30 | 2004-08-12 | Fujitsu Limited | Fading frequency estimation apparatus |
| US7043207B2 (en) | 2003-01-30 | 2006-05-09 | Fujitsu Limited | Fading frequency estimating apparatus |
| JP2012004737A (en) * | 2010-06-15 | 2012-01-05 | Nec Corp | Radio base station device, mobile communication system, communication method thereof and program |
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