JP2756477B2 - Received level adaptive post-detection combining diversity receiver circuit. - Google Patents
Received level adaptive post-detection combining diversity receiver circuit.Info
- Publication number
- JP2756477B2 JP2756477B2 JP1160938A JP16093889A JP2756477B2 JP 2756477 B2 JP2756477 B2 JP 2756477B2 JP 1160938 A JP1160938 A JP 1160938A JP 16093889 A JP16093889 A JP 16093889A JP 2756477 B2 JP2756477 B2 JP 2756477B2
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- JP
- Japan
- Prior art keywords
- diversity
- detection
- combining
- circuit
- weighting
- 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.)
- Expired - Lifetime
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Description
【発明の詳細な説明】 （産業上の利用分野） 本発明はディジタル移動無線伝送においてマルチパス
フェージングによる伝送品質の劣化を改善する合成ダイ
バーシチ受信回路に係わる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combining diversity receiving circuit for improving deterioration of transmission quality due to multipath fading in digital mobile radio transmission.
（従来の技術） ディジタル移動通信ではマルチパスフェージングによ
る回線品質劣化により誤り率特性が劣化する。フェージ
ングの影響を軽減する技術として２つ以上の受信波を利
用するダイバーシチ受信がある。これは複数の受信波に
対するフェージングの相関が小さいことを利用して、一
方の受信波のレベルが落ち込んでも他方の受信波を用い
ることによって良好な品質を実現する技術である。これ
には受信レベルに応じてレベルの高い方の受信波を選択
する選択法、全ての受信波位相を同相にしたうえで受信
波を合成する等利得合成法や受信レベルに比例する重み
付けをしてから受信波を合成する最大比合成法がある。
等利得合成法や最大比合成法は選択法に比べ特性が優れ
るものの、検波前ダイバーシチに適用する場合にはラン
ダムに変動する受信信号の位相を合わせて合成する必要
があり、受信波が高速に変動する移動通信の場合には実
現が困難であった。(Prior Art) In digital mobile communication, error rate characteristics deteriorate due to line quality deterioration due to multipath fading. As a technique for reducing the effect of fading, there is diversity reception using two or more received waves. This is a technology that utilizes the fact that the fading correlation for a plurality of received waves is small and achieves good quality by using the other received wave even if the level of one received wave drops. For this, a selection method of selecting the higher received wave according to the reception level, an equal gain synthesis method of synthesizing the received waves after making all the received wave phases the same, and weighting proportional to the reception level are used. There is a maximum ratio combining method in which received waves are combined afterwards.
The equal gain combining method and the maximum ratio combining method have better characteristics than the selection method, but when applied to pre-detection diversity, it is necessary to combine the phases of the received signals that fluctuate randomly, and the received wave can be processed at high speed. In the case of fluctuating mobile communications, it has been difficult to realize.
そこで検波前ダイバーシチとしては選択法が用いられ
ているが、切替用スイッチが検波器より前に置かれ、切
替は受信波の位相に無関係に行なうから、２つの受信波
の位相連続の切替ができず、切替により生ずる位相ジャ
ンプによって復調後にインパルス性の雑音が生ずるため
に誤りが発生するという欠点がある。これを解決する方
法として検波後のベースバンド信号を受信レベルに応じ
て切り替える検波後選択ダイバーシチが採用されてい
る。Therefore, the selection method is used as the pre-detection diversity. However, the switching switch is placed before the detector, and the switching is performed irrespective of the phase of the received wave. In addition, there is a drawback that an error occurs because impulsive noise occurs after demodulation due to a phase jump caused by switching. As a method for solving this, post-detection selection diversity for switching the baseband signal after detection according to the reception level is employed.
しかし、この方法では常に最も受信レベルの大きい１
ブランチ分の信号しか受信しない。ところが、他のブラ
ンチでもレベルの高い信号が受信されている場合がある
から、これらを検波後に合成すれば伝送特性をさらに改
善することができるはずである。それが検波後合成法で
あり、これにも等利得合成法や最大比合成法がある。こ
れもFSKの周波数検波方式に適用するときの実験例は既
に検討されている。しかし、これらの方式では変調方式
がFSKのため、検波器前にリミタを用いるので検波器出
力を単に合成するだけでは伝送特性の改善は見込めない
という問題があった。However, in this method, the one having the highest reception level is always used.
Only the signal for the branch is received. However, since high-level signals may be received in other branches as well, if these are combined after detection, the transmission characteristics should be further improved. This is the post-detection combining method, which also includes the equal gain combining method and the maximum ratio combining method. Experimental examples when applying this to the FSK frequency detection method have also been studied. However, in these systems, since the modulation system is FSK, a limiter is used before the detector, so that there is a problem that the transmission characteristics cannot be improved by simply combining the detector outputs.
（発明が解決しようとする課題） 本発明は上記問題点に鑑みなされたもので、復調前に
リミタを用いた回路でも伝送特性が改善される検波後合
成ダイバーシチ受信回路を提供することを目的とする。(Problems to be Solved by the Invention) The present invention has been made in view of the above problems, and has as its object to provide a post-detection combining diversity receiving circuit in which transmission characteristics are improved even in a circuit using a limiter before demodulation. I do.
（課題を解決するための手段） 本発明によれば、線形変調を用い受信側で受信信号を
復調した後に各ダイバーシチ枝の信号を合成する検波後
合成ダイバーシチ受信回路において、各ダイバーシチ枝
の受信信号を振幅制限するリミタと、該リミタにより振
幅制限された後の各ダイバーシチ枝の受信信号を復調す
る検波器と、各ダイバーシチ枝の振幅制限前の受信信号
のレベルを検出する受信レベル検出器と、各ダイバーシ
チ枝の前記検波器出力を前記受信信号のレベルに従った
重み付けで合成する重み付け合成器と、該重み付け合成
器の出力に接続されており、データの1,0を判定して出
力するデータ判定回路とを備えており、前記重み付け合
成器と前記データ判定回路とは、多重化信号により時分
割利用される受信レベル適応形検波後合成ダイバーシチ
受信回路が提供される。According to the present invention, in a post-detection combining diversity receiving circuit that combines a signal of each diversity branch after demodulating a received signal on the receiving side using linear modulation, a reception signal of each diversity branch is received. Limiter for limiting the amplitude, a detector for demodulating the received signal of each diversity branch after the amplitude is limited by the limiter, a reception level detector for detecting the level of the received signal before the amplitude limit of each diversity branch, A weighting combiner for combining the detector outputs of the diversity branches by weighting according to the level of the received signal; and a data connected to the output of the weighting combiner for determining and outputting data 1,0. A decision circuit, wherein the weighting combiner and the data decision circuit are combined with each other by a reception level adaptive detection-based combining die which is time-divisionally used by a multiplexed signal. A diversity receiving circuit is provided.
（作用） 復調前にリミタを用いた場合に検波器出力を単に合成
するだけでは伝送特性の改善が見込めないのは、受信レ
ベルの低いブランチの検波器出力に大きな雑音が生ずる
ためである。そこで、検波器出力を受信レベルで重み付
けして合成すればこのような問題は生じない。さらに、
検波後の合成だから受信波位相を同相にする必要もな
い。(Operation) When a limiter is used before demodulation, simply combining detector outputs cannot improve transmission characteristics because large noise is generated in the detector output of a branch having a low reception level. Therefore, such a problem does not occur if the detector outputs are weighted and combined at the reception level. further,
Since the signal is synthesized after detection, it is not necessary to make the phase of the received wave the same.
なお、QPSKなどの多相位相変調信号を検波後合成する
場合には各相毎に重み付け合成回路を必要とし回路規模
が大きくなる問題がある。そこで、本発明では受信レベ
ルに対応して重み付けをした後検波後合成するダイバー
シチ方式において、各相毎の検波信号を時分割で取り込
み、重み付け合成回路、データ判定回路を時分割で利用
することにより、簡易な受信レベル適応形検波後合成ダ
イバーシチ受信回路を提供する。When a multi-phase modulation signal such as QPSK is synthesized after detection, there is a problem that a weighting synthesis circuit is required for each phase and the circuit scale becomes large. Therefore, in the present invention, in a diversity system in which detection is performed after weighting according to the reception level, and then combined after detection, a detection signal for each phase is captured in a time-division manner, and a weighting synthesis circuit and a data determination circuit are used in a time-division manner. And a simple reception level adaptive type post-detection combining diversity receiving circuit.
（実施例） QPSK信号を２つの検波器で遅延検波し、検波信号を重
み付け合成する場合で説明する。本発明の実施例を第１
図に示す。(Embodiment) A case will be described in which a QPSK signal is delayed detected by two detectors, and the detected signals are weighted and combined. First Embodiment of the Invention
Shown in the figure.
入力端子１−１、１−２によりIF信号１、IF信号２を
振幅制限を行うリミタ12−１、12−２を介して遅延検波
器２−１、２−２に入力すると共に、直接受信レベル検
出器３−１、３−２に入力し、COSおよびSIN検波出力
I1,Q1,I2,Q2およびR1,R2を得る。シンボルタイミング毎
にこの検波出力と受信レベルをサンプル＆ホールドす
る。Input signals 1-1 and 1-2 are input to delay detectors 2-1 and 2-2 via limiters 12-1 and 12-2 for limiting the amplitude of IF signals 1 and 2 and are directly received. Input to level detectors 3-1 and 3-2, COS and SIN detection output
I 1 , Q 1 , I 2 , Q 2 and R 1 , R 2 are obtained. The detection output and the reception level are sampled and held at each symbol timing.
サンプリングタイミングを第２図に示す。シンボルタ
イミングは第２図のように、アイパターンの真中に設定
する。遅延検波出力ではI,Qともにこのようなアイパタ
ーンになる。アイが開いているところは最も誤り率特性
が良いところであるから、そこでサンプリングすれば特
性が良くなるからである。また受信レベルも同時にサン
プルする。サンプルした受信レベルを重み付け回路５−
１、５−２に入力する。重み付け合成器６は、スイッチ
９−１、９−２、乗算器10−１、10−２、加算器11によ
り構成される。スイッチ９−１、９−２は第２図に示す
ビットタイミングで連動して動作し、ホールドされた検
波器出力信号I1,I2あるいはQ1,Q2を選択出力し、それぞ
れ重み付け回路出力により乗算器10−１、10−２により
重み付けして加算器11により合成し、信号ＩあるいはＱ
として出力する。データ判定器７は重み付け合成器６の
出力信号ＩあるいはＱをビットタイミング毎にスレシホ
ールドレベルと比較して符号判定し、出力端子８に２値
データとして出力する。つまり８からはＩ出力とＱ出力
が時分割されて出力される。FIG. 2 shows the sampling timing. The symbol timing is set in the middle of the eye pattern as shown in FIG. In the delayed detection output, both I and Q have such an eye pattern. This is because the portion where the eye is open is where the error rate characteristics are the best, and if the sampling is performed there, the characteristics are improved. The reception level is also sampled at the same time. Weighting circuit 5-
Input to 1, 5-2. The weighting synthesizer 6 includes switches 9-1 and 9-2, multipliers 10-1 and 10-2, and an adder 11. The switches 9-1 and 9-2 operate in conjunction with each other at the bit timing shown in FIG. 2, and selectively output the held detector output signals I 1 and I 2 or Q 1 and Q 2 and output the respective weighting circuit outputs. , Weighted by multipliers 10-1 and 10-2, combined by adder 11, and signal I or Q
Output as The data decision unit 7 compares the output signal I or Q of the weighting / synthesizing unit 6 with the threshold level for each bit timing, judges the sign, and outputs it to the output terminal 8 as binary data. In other words, from 8 the I output and the Q output are output in a time-sharing manner.
第１図に示す実施例においてホールドされた受信レベ
ルR1,R2およびCOS検波出力I1,I2、SIN検波出力Q1,Q2を
順次A/D変換したのち重み付け合成をDSPなどの信号処理
回路を用いて実現し、演算結果をデータ判定して出力す
ることもできる。In the embodiment shown in FIG. 1 , the reception levels R 1 , R 2 and the COS detection outputs I 1 , I 2 and the SIN detection outputs Q 1 , Q 2 held in the embodiment shown in FIG. It is also possible to realize by using a signal processing circuit, determine the operation result as data, and output the result.
（発明の効果） 以上説明したように本発明によれば合成回路を複数必
要とせず、簡易に受信レベル適応形検波後合成ダイバー
シチ受信回路を実現することができる。(Effects of the Invention) As described above, according to the present invention, it is possible to easily realize a reception level adaptive post-detection combining diversity receiving circuit without requiring a plurality of combining circuits.
受信レベルのｎ乗に比例する重み付けをする場合につ
いて、ｎと合成受信後の誤り率との関係について測定し
た結果を第３図に示す。また、比較のため検波後選択合
成の特性も示した。これより、ｎとしては受信レベルの
1.5とすることにより選択合成ダイバーシチに比較して
改善が得られる。FIG. 3 shows the measurement results of the relationship between n and the error rate after combined reception when weighting is performed in proportion to the nth power of the reception level. The characteristics of selective synthesis after detection are also shown for comparison. From this, n is the reception level.
By setting it to 1.5, an improvement can be obtained as compared with selective combining diversity.
第４図に誤り率特性を示した。２ブランチを用いる場
合、誤り率が10-2において選択ダイバーシチより約1.5d
B大きな利得が得られている。このように、本発明を用
いると簡易な回路構成でかつ従来の選択ダイバーシチよ
り大きな結果が得られる。特に本発明によれば、リミタ
を用いて振幅制限を行った後に検波してその出力を合成
する場合に、振幅制限前の受信信号のレベルを検出しそ
の検出出力に従って検波器出力を重み付けして合成して
いるので、振幅制限後の復調で問題となっていた、受信
レベルの低いブランチの検波器出力に大きな雑音が生じ
て伝送特性を改善できないという不都合を解消すること
ができる。FIG. 4 shows the error rate characteristics. When using two branches, the error rate is about 1.5d from selection diversity at 10 -2
B Large gain is obtained. As described above, according to the present invention, a simple circuit configuration and a larger result than the conventional selection diversity can be obtained. In particular, according to the present invention, when detecting and synthesizing the output after performing amplitude limitation using a limiter, the level of the received signal before the amplitude limitation is detected, and the detector output is weighted according to the detection output. Since the synthesis is performed, it is possible to solve the problem that the transmission characteristics cannot be improved due to the generation of large noise in the detector output of the branch having a low reception level, which has been a problem in demodulation after limiting the amplitude.
第１図は本発明による検波後合成ダイバーシチ受信回路
のブロック図、 第２図は第１図におけるサンプリングタイミングの例を
示す図、 第３図と第４図は本発明の効果を示す図である。 １−1,1−2;入力端子、 ２−1,2−2;遅延検波器、 ３−1,3−2;受信レベル検出器、 4;サンプルホールド回路、 ５−1,5−2;重み付け回路、 6;重み付け合成器、 7;データ判定回路、 8;入力端子、 12−1,12−2;リミタ。FIG. 1 is a block diagram of a post-detection combining diversity receiver circuit according to the present invention, FIG. 2 is a diagram showing an example of sampling timing in FIG. 1, and FIGS. 3 and 4 are diagrams showing effects of the present invention. . 1-1, 1-2; input terminal, 2-1, 2-2; delay detector, 3-1, 3-2; reception level detector, 4; sample and hold circuit, 5-1, 5-2; Weighting circuit, 6; weighting combiner, 7; data judgment circuit, 8; input terminal, 12-1, 12-2; limiter.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭63−313934（ＪＰ，Ａ) 特開 昭62−85523（ＪＰ，Ａ) 特開 昭60−48627（ＪＰ，Ａ) 特開 平２−305135（ＪＰ，Ａ) ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-313934 (JP, A) JP-A-62-85523 (JP, A) JP-A-60-48627 (JP, A) JP-A-2- 305135 (JP, A)
Claims (1)
た後に各ダイバーシチ枝の信号を合成する検波後合成ダ
イバーシチ受信回路において、 各ダイバーシチ枝の受信信号を振幅制限するリミタと、 該リミタにより振幅制限された後の各ダイバーシチ枝の
受信信号を復調する検波器と、 各ダイバーシチ枝の振幅制限前の受信信号のレベルを検
出する受信レベル検出器と、 各ダイバーシチ枝の前記検波器出力を前記受信信号のレ
ベルに従った重み付けで合成する重み付け合成器と、 該重み付け合成器の出力に接続されており、データの1,
0を判定して出力するデータ判定回路とを備えており、 前記重み付け合成器と前記データ判定回路とは、多重化
信号により時分割利用されることを特徴とする受信レベ
ル適応形検波後合成ダイバーシチ受信回路。1. A post-detection combining diversity receiving circuit for combining signals of diversity branches after demodulating a received signal on the receiving side using linear modulation, a limiter for limiting the amplitude of a received signal of each diversity branch, A detector for demodulating the received signal of each diversity branch after the amplitude limitation, a reception level detector for detecting the level of the received signal before the amplitude limitation of each diversity branch, and the detector output of each diversity branch. A weighting combiner for combining by weighting according to the level of the received signal; connected to an output of the weighting combiner,
A data decision circuit for judging and outputting 0, wherein the weighting combiner and the data decision circuit are time-divisionally used by a multiplexed signal, and the reception level adaptive post-detection combining diversity is provided. Receiver circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1160938A JP2756477B2 (en) | 1989-06-26 | 1989-06-26 | Received level adaptive post-detection combining diversity receiver circuit. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1160938A JP2756477B2 (en) | 1989-06-26 | 1989-06-26 | Received level adaptive post-detection combining diversity receiver circuit. |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0327626A JPH0327626A (en) | 1991-02-06 |
| JP2756477B2 true JP2756477B2 (en) | 1998-05-25 |
Family
ID=15725477
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1160938A Expired - Lifetime JP2756477B2 (en) | 1989-06-26 | 1989-06-26 | Received level adaptive post-detection combining diversity receiver circuit. |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2756477B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| MY113061A (en) * | 1994-05-16 | 2001-11-30 | Sanyo Electric Co | Diversity reception device |
| CN100387206C (en) * | 1997-02-03 | 2008-05-14 | 伊东宽治 | Phimosis correctional appliance |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6285523A (en) * | 1985-10-09 | 1987-04-20 | Nec Corp | Adaptive receiving equipment |
| JPS63313934A (en) * | 1987-06-17 | 1988-12-22 | Toshiba Corp | Digital radio receiver |
-
1989
- 1989-06-26 JP JP1160938A patent/JP2756477B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0327626A (en) | 1991-02-06 |
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