JP3325731B2 - Adaptive equalization method in mobile communication - Google Patents
Adaptive equalization method in mobile communicationInfo
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- JP3325731B2 JP3325731B2 JP30422494A JP30422494A JP3325731B2 JP 3325731 B2 JP3325731 B2 JP 3325731B2 JP 30422494 A JP30422494 A JP 30422494A JP 30422494 A JP30422494 A JP 30422494A JP 3325731 B2 JP3325731 B2 JP 3325731B2
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- Japan
- Prior art keywords
- correlation
- correlation peak
- wave
- received signal
- equalization
- Prior art date
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- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
- Mobile Radio Communication Systems (AREA)
Description
【0001】[0001]
【産業上の利用分野】本発明は、陸上移動通信等におい
て発生し高速伝送時に支障となる周波数選択性フェージ
ングを補償するための適応等化方式に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adaptive equalization system for compensating for frequency selective fading which occurs in land mobile communication and the like and hinders high speed transmission.
【0002】[0002]
【従来の技術】このような周波数選択性フェージング対
策のための適応等化方式として、ビタビ等化器や判定帰
還型等化器(DFE:Decision Feedback Equalizer )
が有効であった。しかしビタビ等化器は、補償の対象と
なる遅延時間の範囲が増大した場合や、16QAMのよ
うな多値変調方式に適用する場合には、ビタビ複号にお
いて考慮すべき状態数が増加し、演算量が指数関数的に
増加するため実現が困難となる。一方、DFEは、比較
的小規模で実現でき、遅延時間が大きな場合でも等化可
能である。図7にDFEの構成図を示す。図中前段のフ
ィードフォワードフィルタ(以下FFフィルタ)1は、
直接波と遅延波を取り込んだダイバーシチ効果を得るた
めの整合処理を実行する。後段のフィードバックフィル
タ(以下FBフィルタ)2は、検波器4による判定出力
を帰還することにより残留遅延波の除去を行う。このよ
うな多重波成分のダイバーシチ合成やキャンセル動作に
よって等化機能を実現している。陸上移動通信において
は、D/U(直接波の電力と遅延波の電力の比:Desire
to Undesire Power Ratio)が頻繁に入れ替わる。ここ
でD>Uの場合最小位相系とよばれ、逆にD<Uの場合
非最小位相系と呼ばれている。前述の通り、残留遅延波
はFBフィルタ2の出力によって加算器3において打ち
消すわけであるが、非最小位相系の場合は遅延波のレベ
ルが大きいことから打ち消しが困難となり等化特性が劣
化する。そこで、残留遅延波が残らないようにFFフィ
ルタ1のタップ数を増加させることとなるが、やはりビ
タビ等化器と同様にタップ数の二乗に比例して演算量が
急増してしまう。2. Description of the Related Art Viterbi equalizers and Decision Feedback Equalizers (DFEs) are known as adaptive equalization methods for preventing such frequency selective fading.
Was effective. However, the Viterbi equalizer increases the number of states to be considered in Viterbi decoding when the range of delay time to be compensated increases or when applied to a multilevel modulation scheme such as 16QAM. Since the amount of calculation increases exponentially, implementation becomes difficult. On the other hand, DFE can be realized on a relatively small scale, and can be equalized even when the delay time is large. FIG. 7 shows a configuration diagram of the DFE. The feedforward filter (hereinafter referred to as FF filter) 1 in the first stage in the figure is
A matching process for obtaining a diversity effect incorporating a direct wave and a delayed wave is executed. A feedback filter (hereinafter, referred to as an FB filter) 2 at a subsequent stage removes a residual delay wave by feeding back a determination output from the detector 4. An equalization function is realized by such a diversity combining and canceling operation of the multiple wave components. In land mobile communication, D / U ( the ratio of the power of the direct wave to the power of the delayed wave: Desire
to Undesire Power Ratio) changes frequently. Here, when D> U, it is called a minimum phase system, and when D <U, it is called a non-minimum phase system. As described above, the residual delay wave is canceled in the adder 3 by the output of the FB filter 2. In the case of a non-minimum phase system, the level of the delay wave is large, so it is difficult to cancel and the equalization characteristics deteriorate. Therefore, the number of taps of the FF filter 1 is increased so that the residual delay wave does not remain. However, as in the case of the Viterbi equalizer, the amount of calculation increases rapidly in proportion to the square of the number of taps.
【0003】そこで、このようなDFEの欠点を改善す
るため、両方向等化方式が提案されている。両方向等化
方式の構成を図8に示す。構成にしたがって動作を説明
する。まずこの方式の場合のフレーム構成は、図9に示
すように、フレームの両端にデータを挟む形でトレーニ
ング信号を配置し、それぞれプリアンブル信号(UW
1)、ポストアンブル信号(UW2)と呼んでいる。受
信信号はA/D変換器5でA/D変換の後、フレーム同
期信号がフレーム同期回路6で捕捉され、受信バッファ
7に蓄積される。次に、順方向等化用DFE8、逆方向
等化用DFE9の2つを用いて受信バッファ7の前方か
らと受信バッファ7の後方からの両方向から等化を行い
出力バッファ10,11に一次蓄積する。次に、それぞ
れの等化誤差は誤差バッファ12,13に一次蓄積さ
れ、それらは比較器14で比較され良好に等化された方
の出力を方向制御器15でスイッチ16を制御して選択
する方式である。[0003] In order to improve such a drawback of the DFE, a bidirectional equalization system has been proposed. FIG. 8 shows the configuration of the bidirectional equalization system. The operation will be described according to the configuration. First, as shown in FIG. 9, the frame structure in this system is such that a training signal is arranged at both ends of a frame with data interposed therebetween, and a preamble signal (UW
1), called a postamble signal (UW2). After the received signal is A / D converted by the A / D converter 5, the frame synchronization signal is captured by the frame synchronization circuit 6 and stored in the reception buffer 7. Next, equalization is performed from both directions from the front of the reception buffer 7 and the rear of the reception buffer 7 by using two of the DFE 8 for forward equalization and the DFE 9 for backward equalization, and the primary accumulation is performed in the output buffers 10 and 11. I do. Next, the respective equalization errors are primarily stored in error buffers 12 and 13, which are compared by a comparator 14 to select a better equalized output by controlling a switch 16 with a direction controller 15. It is a method.
【0004】[0004]
【発明が解決しようとする課題】この両方向等化方式に
おいて、後方からの等化は時間を反転して扱うため遅延
波を直接波として処理することになる。すなわち、D<
Uの条件をD>Uとみなして処理できるため、FFフィ
ルタ1のタップ数を増加させることなく非最小位相系に
おける等化特性を大幅に改善することができる。しかし
この方式では両方向から等化するため、必然的に演算量
は2倍になってしまうという欠点がある。In this two-way equalization method, since the backward equalization is performed by inverting the time, the delayed wave is processed as a direct wave. That is, D <
Since the condition of U can be processed assuming that D > U, the FF file
The equalization characteristics in the non-minimum phase system can be greatly improved without increasing the number of taps of the filter 1. However, in this method, since the equalization is performed from both directions, there is a disadvantage that the amount of calculation is inevitably doubled.
【0005】本発明の目的は、従来のDFEに対して
は、わずかな演算量の増加で大幅な等化特性の改善を図
り、また両方向等化方式に対しては、等化特性を劣化さ
せることなく従来の欠点である膨大な演算量を低減する
ことにより実時間処理を容易としハードウェア規模を減
少することができる移動通信における適応等化方式を提
供するものである。An object of the present invention is to greatly improve the equalization characteristics with a small increase in the amount of calculation for the conventional DFE, and to degrade the equalization characteristics for the bidirectional equalization method. It is an object of the present invention to provide an adaptive equalization method in mobile communication capable of facilitating real-time processing and reducing a hardware scale by reducing a huge amount of computation, which is a conventional disadvantage.
【0006】[0006]
【課題を解決するための手段】この目的を達成するため
に、本発明による移動通信における適応等化方式は、従
来方式である両方向等化方式の場合、D/Uが非最小位
相系(D<U)にある場合には時間の逆方向からの等化
が有効であることに着目し、予めD/Uを検出すること
が可能であれば、両方向の等化を行う必要はなく、最小
位相系(D>U)であれば従来のDFEと同様に時間方
向のみの等化をし、非最小位相系(D<U)であれば逆
の時間方向のみの等化をするように等化方向を選択する
ことにより、演算量の大幅な低減を図るように構成され
ている。In order to achieve this object, the adaptive equalization system in mobile communication according to the present invention uses a non-minimum phase system (D / U) in the case of a conventional bidirectional equalization system. In the case of <U), paying attention to the fact that equalization from the reverse direction of time is effective, if D / U can be detected in advance, it is not necessary to perform equalization in both directions. For a phase system (D> U), equalization only in the time direction is performed in the same manner as the conventional DFE, and for a non-minimum phase system (D <U), equalization only in the reverse time direction is performed. The configuration is such that the amount of calculation can be significantly reduced by selecting the conversion direction.
【0007】[0007]
【実施例】図面により本発明を詳細に説明する。図1に
本発明の一実施例のブロック図を示す。フレーム構成は
両方向等化方式の場合と同様なものを用いることとす
る。受信信号は、A/D変換器20によってディジタル
信号に変換された後、フレーム同期回路21によって平
均的に電力の大きい波の同期信号が捕捉されて受信バッ
ファ22に蓄積される。この際、D/Uが非最小位相系
にあるときに遅延波(U波)に同期してしまう場合を考
慮して、その伝搬上で予想される最大遅延時間、もしく
は等化器のタップ数によって決められる等化可能最大遅
延時間(τ)以上前から受信バッファ22に蓄積する。
また受信バッファ長も実際のフレーム長よりτ以上長く
確保する。次にユニークワード相関器(以下UW相関
器)23において受信信号と既知のユニークワード(ト
レーニング信号:プリアンブルまたはポストアンブル)
との相互相関演算を行う。相互相関(1)式に示す。BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 shows a block diagram of one embodiment of the present invention. A frame configuration similar to that of the bidirectional equalization system is used. After the received signal is converted into a digital signal by the A / D converter 20, a synchronization signal of a wave having a high average power is captured by the frame synchronization circuit 21 and stored in the reception buffer 22. At this time, in consideration of the case where the D / U is synchronized with the delay wave (U wave) when the D / U is in the non-minimum phase system, the maximum delay time expected on the propagation or the number of taps of the equalizer Is stored in the reception buffer 22 before the maximum equalizable delay time (τ) determined by the above.
Also, the length of the receiving buffer is ensured to be longer than the actual frame length by τ or more. Then the received signal to have you in the unique word correlator (following UW correlator) 23 and the known unique word (training signal: preamble or post-amble)
And a cross-correlation operation is performed. The cross-correlation is shown in equation (1).
【0008】[0008]
【数1】 この相関値列yj は受信バッファ22の先頭から2τま
での範囲で検出する。検出された相関値の一例を図2に
示す。(Equation 1) The correlation value sequence y j is detected in a range from the head of the reception buffer 22 to 2τ. FIG. 2 shows an example of the detected correlation value.
【0009】次に相関ピーク検出器24によって相関値
yから相関値のピーク値が最大の点と2番目の点を検出
する。2波モデルで考えた場合、この二つの点で直接波
(D波)と遅延波(U波)と見なすことができる。次に
D/U判定によってこの処理フレームのD/Uが最小位
相系か非最小位相系かを判定する。図2に示すように相
関値が最大である点が時間軸上で前にあり2番目の点が
後にある場合、D>Uとなり最小位相系と見なすことが
できる。逆に図3に示すように最大である点が時間軸上
で後にあり2番目の点が時間軸上で前にある場合、D<
Uとなり非最小位相系と見なすことができる。その結
果、方向制御器25において最小位相系の場合、D波の
点から順方向で等化処理を行うべく方向切り替え器28
を順方向側に切り替え、反対に非最小位相系の場合はU
波の到達点からフレーム長分だけ後から時間軸を反対に
等化器26で等化処理を行うべく方向切り替え器28を
逆方向に切り替える。等化後の出力バッファ30の出力
側の切り替え器29も同様に切り替える。Next, the correlation peak detector 24 detects a point where the peak value of the correlation value is the maximum and a second point from the correlation value y. In the case of a two-wave model, these two points can be regarded as a direct wave (D wave) and a delayed wave (U wave). Next, it is determined by D / U determination whether the D / U of this processing frame is a minimum phase system or a non-minimum phase system. As shown in FIG. 2, when the point having the largest correlation value is before and the second point is after on the time axis, D> U, and it can be regarded as the minimum phase system. Conversely, as shown in FIG. 3, when the maximum point is on the time axis and the second point is on the time axis, D <
U, which can be regarded as a non-minimum phase system. As a result, in the case of the minimum phase system in the direction controller 25, the direction switcher 28 performs the equalization process in the forward direction from the point of the D wave.
To the forward direction, and conversely, for non-minimum phase systems, U
The direction switch 28 is switched in the opposite direction so that the equalizer 26 performs the equalization process with the time axis reversed after the frame length from the wave arrival point. The switch 29 on the output side of the output buffer 30 after the equalization is similarly switched.
【0010】上記の例は、二波モデルの場合であるが、
実際の伝送路上で到来する電波は必ずしも二波ではな
く、1波のみの場合もあれば3波以上の複数の遅延波が
合成されている場合も考えられる。そこでこれらの条件
を考慮した処理方法を説明する。まず、前述の例と同様
にUW相関器23において受信信号と既知のユニークワ
ードとの相互相関演算を行う。次に相関ピーク検出器2
4によって、最大ピーク点を検出する。次に最大ピーク
点基準としたしきい値を設定する。このしきい値は最大
ピーク値の振幅の0%以上100%未満の値を設定す
る。しきい値を設定する理由は、等化処理を行うにあた
って遅延波のレベルがノイズと見なされる程度に小さい
場合はその遅延波を無視することが出来るためである。
次に相関値列yから相関値の振幅の大きい順にしきい値
Vthを越える複数のピーク点を検出する。これら複数の
ピーク点とは、図4に示す部分である。しきい値を越え
る2番目のピークが検出されない場合には、直接波のみ
と判断しピーク点から順方向の等化処理を行う。また、
しきい値を越える3番目,4番目のピークが検出された
場合には等化の対象とする遅延波が複数あるものとし、
それらの時間軸上での位置関係から等化方向を選択す
る。この方法は、3波以上検出された相関ピークのう
ち、時間軸上で最も前の相関ピークと最も後の相関ピー
クの振幅比をD/Uと見なして方向を決定する。図5に
示すように時間軸上で最も前にある相関ピークが最も後
にある相関ピークより大きい場合、最小位相系(D>
U)と見なすことができる。逆に図6に示すように時間
軸上で最も前にある相関ピークが最も後にある相関ピー
クより小さい場合、非最小位相系(D<U)と見なすこ
とができる。その結果、2波モデルの場合と同様に、最
小位相系の場合、D波の点から順方向で等化処理を行う
べく方向切り替え器を順方向に切り替え、反対に非最小
位相系の場合にはU波の到達点からフレーム長分だけ後
から時間軸を反対に等化処理を行うべく方向切り替え器
を逆方向側に切り替える。以上の処理によって、複数の
マルチパスが到来する場合でも正確に等化する方向を検
出することができる。The above example is for the two-wave model,
The radio waves arriving on the actual transmission path are not necessarily two waves, but may be only one wave or a case where a plurality of three or more delayed waves are combined. Therefore, a processing method considering these conditions will be described. First, as in the above-described example, the UW correlator 23 performs a cross-correlation operation between the received signal and the known unique word. Next, the correlation peak detector 2
4, the maximum peak point is detected. Next, a threshold based on the maximum peak point is set. This threshold value is set to a value between 0% and 100% of the amplitude of the maximum peak value. The reason for setting the threshold value is that when the level of the delayed wave is small enough to be regarded as noise in performing the equalization process, the delayed wave can be ignored.
Next, a plurality of peak points exceeding the threshold value Vth are detected from the correlation value sequence y in descending order of the amplitude of the correlation value. These plural peak points are the portions shown in FIG. If the second peak exceeding the threshold is not detected, it is determined that only direct waves are present, and a forward equalization process is performed from the peak point. Also,
If the third and fourth peaks exceeding the threshold are detected, it is assumed that there are a plurality of delayed waves to be equalized,
The equalizing direction is selected from the positional relationship on the time axis. In this method, among three or more detected correlation peaks, the direction is determined by regarding the amplitude ratio between the earliest correlation peak and the latest correlation peak on the time axis as D / U. As shown in FIG. 5, when the first correlation peak on the time axis is larger than the last correlation peak, the minimum phase system (D>
U). Conversely, if the earliest correlation peak on the time axis is smaller than the last correlation peak as shown in FIG. 6, it can be regarded as a non-minimum phase system (D <U). As a result, as in the case of the two-wave model, in the case of the minimum phase system, the direction switch is switched in the forward direction so as to perform equalization processing in the forward direction from the point of the D wave. Switches the direction switch to the opposite direction in order to perform the equalization processing in the opposite direction on the time axis after the frame length from the arrival point of the U wave. By the above processing, even when a plurality of multipaths arrive, the direction of equalization can be accurately detected.
【0011】[0011]
【発明の効果】本発明を用い、予めD/Uを検出して等
化する時間軸の方向を決定することによって、両方向か
ら等化する必要がなくなり、演算量を従来方式の半分程
度に減少することができ、実時間処理が容易となりハー
ドウェア規模も減少することができる。According to the present invention, it is not necessary to perform equalization from both directions by detecting the D / U in advance and determining the direction of the time axis for equalization, and the amount of calculation is reduced to about half that of the conventional method. And real-time processing is facilitated, and the hardware scale can be reduced.
【図1】本発明の実施例を示す構成図である。FIG. 1 is a configuration diagram showing an embodiment of the present invention.
【図2】最小位相系時の相関値列を示すタイムチャート
である。FIG. 2 is a time chart showing a correlation value sequence in a minimum phase system.
【図3】非最小位相系時の相関値列を示すタイムチャー
トである。FIG. 3 is a time chart showing a correlation value sequence in a non-minimum phase system.
【図4】複数の相関ピークの検出を説明するためのタイ
ムチャートである。FIG. 4 is a time chart for explaining detection of a plurality of correlation peaks.
【図5】マルチパス到来時の相関値列(D>U)を説明
するためのタイムチャートである。FIG. 5 is a time chart for explaining a correlation value sequence (D> U) when a multipath arrives.
【図6】マルチパス到来時の相関値列(D<U)を説明
するためのタイムチャートである。FIG. 6 is a time chart for explaining a correlation value sequence (D <U) when a multipath arrives.
【図7】DFE(判定帰還型等化器)の基本的な構成を
示すブロック図である。7 is a block diagram showing a basic configuration of the DF E (Decision Feedback Equalizer).
【図8】従来の両方向等化方式の構成例図である。FIG. 8 is a diagram illustrating a configuration example of a conventional bidirectional equalization method.
【図9】両方向等化方式の場合のフレーム構成例図であ
る。FIG. 9 is a diagram illustrating an example of a frame configuration in a case of a bidirectional equalization method.
1 FFフィルタ 2 FBフィルタ 3 加算器 4 検波器 5 A/D変換器 6 フレーム同期回路 7 受信バッファ 8 順方向用DFE 9 逆方向用DFE 10,11 出力バッファ 12,13 誤差バッファ 14 比較器 15 方向制御器 16 スイッチ 20 A/D変換器 21 フレーム同期回路 22 受信バッファ 23 UW相関器 24 相関ピーク検出器 25 方向制御器 26 判定帰還型等化器(DFE) 28,29 切り替え器 30 出力バッファReference Signs List 1 FF filter 2 FB filter 3 Adder 4 Detector 5 A / D converter 6 Frame synchronization circuit 7 Receive buffer 8 DFE for forward direction 9 DFE for reverse direction 10, 11 Output buffer 12, 13 Error buffer 14 Comparator 15 Direction Controller 16 Switch 20 A / D Converter 21 Frame Synchronization Circuit 22 Receive Buffer 23 UW Correlator 24 Correlation Peak Detector 25 Direction Controller 26 Decision Feedback Equalizer (DFE) 28,29 Switching Device 30 Output Buffer
Claims (1)
て時系列に受信バッファに蓄積し、等化処理に先立って
直接波Dと遅延波Uの電力比D/Uから前記蓄積された
受信信号列が最小位相系であるか非最小位相系であるか
をD/U判定手段によって判定し、その判定結果に従っ
て等化処理方向を時間軸方向又はその逆方向に選択して
判定帰還型等化器により前記蓄積された受信信号列の等
化処理を行うように構成された適応等化方式であって、前記D/U判定手段は、 前記受信バッファに蓄積された
受信信号列の受信サンプルと既知のユニークワードとの
相互相関演算を行って相関値を算出し相関値列を出力す
るユニークワード相関器と、前記相関値列の中から検出
した最大ピーク値の振幅の0%以上〜100%未満の値
をしきい値として設定するとともに該相関値列から該し
きい値を超える複数の相関ピーク点を検出する相関ピー
ク検出器と、前記複数の相関ピーク点の最前の相関ピー
ク値と最後の相関ピーク値とを比較し、最前の相関ピー
ク値が最後の相関ピーク値より大きいとき前記受信信号
列が最小位相系(D>U)であると判定して該受信信号
列を直接波Dが到達した時点から時間軸方向に等化処理
を行い、逆に最後の相関ピーク値が最前の相関ピーク値
より大きいとき前記受信信号列が非最小位相系(D<
U)であると判定して該受信信号列を遅延波Uが到達し
た時点から処理フレーム長分だけ後から時間軸を逆方向
に等化処理を行って等化出力を得る制御をする方向制御
器とを備え、 複数の遅延波Uが到来したときも効率よく直接波Dの等
化処理が行われるようにしたことを特徴とする移動通信
における適応等化方式。 1. A signal wirelessly transmitted from a transmission side is received and stored in a reception buffer in a time-series manner.
From the power ratio D / U of the direct wave D and the delayed wave U, the stored
Whether the received signal sequence is the minimum phase system or non-minimum phase system
Is determined by the D / U determination means, and the equalization processing direction is selected in the time axis direction or the reverse direction in accordance with the determination result, and the stored feedback signal sequence is equalized by the determination feedback equalizer. a structure adaptive equalization scheme as the D / U determination means, a correlation value by performing correlation calculation between the received samples and the known unique word of the received signal sequence stored in the receiving buffer A unique word correlator that calculates and outputs a correlation value sequence, and detects from the correlation value sequence
0% to less than 100% of the amplitude of the maximum peak value
Is set as a threshold value, and
Correlation peak to detect multiple correlation peak points exceeding the threshold
A peak detector and a correlation peak before the plurality of correlation peak points.
The last correlation peak value is compared with the last correlation peak value.
The received signal is greater than the last correlation peak value.
The sequence is determined to be a minimum phase system (D> U) and the received signal
Equalization processing in the time axis direction from the point when the wave D arrives directly in the column
And conversely, the last correlation peak value is the previous correlation peak value
When the received signal sequence is larger than the non-minimum phase system (D <
U) and the delayed wave U arrives at the received signal sequence.
The time axis in the reverse direction after the processing frame length
Direction control to perform equalization processing to obtain equalized output
A plurality of delayed waves U, and a direct wave D can be efficiently transmitted even when a plurality of delayed waves U arrive.
Mobile communication characterized in that a conversion process is performed
Adaptive equalization scheme in.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP30422494A JP3325731B2 (en) | 1994-11-15 | 1994-11-15 | Adaptive equalization method in mobile communication |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP30422494A JP3325731B2 (en) | 1994-11-15 | 1994-11-15 | Adaptive equalization method in mobile communication |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH08149056A JPH08149056A (en) | 1996-06-07 |
JP3325731B2 true JP3325731B2 (en) | 2002-09-17 |
Family
ID=17930506
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP30422494A Expired - Fee Related JP3325731B2 (en) | 1994-11-15 | 1994-11-15 | Adaptive equalization method in mobile communication |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3325731B2 (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3145295B2 (en) * | 1995-12-27 | 2001-03-12 | 松下電器産業株式会社 | Data receiving device |
JP2005159467A (en) * | 2003-11-20 | 2005-06-16 | Sanyo Electric Co Ltd | Equalizing method and receiver utilizing it |
KR20080104836A (en) | 2007-05-29 | 2008-12-03 | 삼성전자주식회사 | Bidirectional equalizer for improving equalization efficiency using the viterbi decoder information and method for equalizing using the same |
JP5107745B2 (en) * | 2007-05-29 | 2012-12-26 | 株式会社日立国際電気 | Equalizer |
JP5312921B2 (en) * | 2008-11-28 | 2013-10-09 | 株式会社日立国際電気 | Receiver and equalization processing method |
WO2022244141A1 (en) * | 2021-05-19 | 2022-11-24 | 日本電信電話株式会社 | Communication device and estimation method |
-
1994
- 1994-11-15 JP JP30422494A patent/JP3325731B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPH08149056A (en) | 1996-06-07 |
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