JPH0856187A - Diversity receiver - Google Patents

Abstract

PURPOSE:To suppress the reduction in the diversity effect due to deviated identification timing when the diversity reception of a digital angular modulation wave is conducted. CONSTITUTION:When the detection output of detectors 7, 8 is selected in the diversity receiver, timing quality discrimination devices 51, 52 and a quality comparator 53 monitoring the quality of the identification timing signal of the detectors 7, 8 for each branch for discrimination are provided to select a detection output. Thus, the reduction in the effect of diversity reception due to deterioration in a timing signal depending on deterioration in the quality of a transmission line is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital angle modulated wave diversity receiver used in mobile communication and the like.

[0002]

2. Description of the Related Art In recent years, with the rapid practical use of digitalization in the field of mobile communication, as a method for improving the characteristics of a receiver,
Several technologies have been proposed. As a problem peculiar to mobile communications, the diversity reception method is effective as a compensation method for fluctuations in the reception level due to fading caused by fluctuations in the transmission path characteristics, especially when the level drops sharply. Has also been considered.
It has been found that diversity reception is an effective means for improving characteristics even in digital transmission.

A conventional diversity receiving method will be described below. FIG. 4 shows the configuration of a conventional diversity receiving method. In FIG. 4, reference numerals 1 and 2 are received modulated wave input signals, 3 and 4 are reception RF and IF sections, which appropriately include frequency conversion means, band limiting means, etc., 5 and 6 are logarithmic amplifiers for reception level detection, and 7 and 8. Is a detection means of the digital angle modulated wave, 9 is a receiving level signal comparison circuit, 10 is a detection output switching circuit for switching the detection signal according to the comparison result, 11
Is the final data output signal.

The operation of the diversity receiving method configured as above will be described below. The configuration shown in FIG. 4 is a generally used diversity reception system, and modulated signals 1 and 2 received from different antennas (although two branches are shown in this case) are received by each reception system. The comparator circuit 9 has a configuration in which the reception level is input, the reception level is detected by the comparison circuit 9, the maximum one is selected by the switcher 10, and thereby the detection signal is selectively output.

FIG. 5 shows the structure of another conventional diversity receiving method. 5, in addition to the configuration shown in FIG. 4, phase degree estimation units 41 and 42 for calculating the phase degree of the detection signal, and a degree comparator 4 for comparing the degrees
3 and the point that a switch 44 is provided for switching the result of the power comparison by the comparator 44 for comparing the result of the level comparison with the result of the level comparison.

In the above example, the degree of phase is introduced as an index of the quality of the received signal of the digital modulation signal, and not only the level comparison but also the signal after detection is directly used to select the best branch.

[0007]

However, in the conventional configuration of FIG. 4, since the diversity detection method requires analog elements such as a level detection circuit using a logarithmic amplifier and a comparison circuit for level comparison, There is a problem that adjustment of this portion is troublesome. Also,
In the conventional example shown in FIG. 5, the provision of the detection circuit for the degree of brightness is disadvantageous in terms of the circuit scale, and neither example considers the reproduction of the identification timing in each branch, and thus multipath fading is performed. However, there is a problem that the consistency between the branches cannot be obtained when the identification timing is significantly deviated.

The present invention solves the above-mentioned problems of the prior art. It is possible to obtain a diversity effect without performing level detection and comparison of received signals, and to use a multipath that does not assume the use of an equalizer or the like. It is an object of the present invention to provide a diversity receiver which is advantageous in terms of circuit scale and can be applied even when the identification timing is greatly different between branches due to fluctuations in the transmission path due to fading or the like.

[0009]

In order to achieve this object, the present invention is based on the detection means for respectively detecting a plurality of branches received by receiving a digital angle modulated wave, and the detection result of the detection means. Identification timing quality estimation means for estimating the quality of the identification timing, quality comparison means for comparing the quality of the outputs of the identification timing quality estimation means, and detection signals by the detection means of a plurality of branches based on the comparison result of the quality comparison means. And a selection means for switching between.

[0010]

With the above structure, the present invention estimates the reception quality corresponding to the fluctuation of the transmission line by monitoring the reproduction identification timing of each branch, and the best detection output can be selected based on this estimation result. is there. Further, by monitoring the identification timing, it is possible to detect a sudden change in the timing signal in advance and suppress the occurrence of inconsistency at the switching timing.

As the branch selection information, in addition to the configuration of performing all by monitoring the clock, a configuration of combining with the phase information or the reception level can be considered.

[0012]

【Example】

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a diversity receiver according to the first embodiment of the present invention. FIG.
Shows the case where the number of branches is 2, but it is generally applicable when the number of branches is n (n> = 2).

In FIG. 1, reference numerals 1 and 2 are received modulated wave input signals, 3 and 4 are received RF and IF sections, which appropriately include frequency conversion means, band limiting means and the like, and 7 and 8 are digital angle modulated wave detection means. Reference numerals 51 and 52 are identification timing quality estimators for estimating the quality of the identification timing from a plurality of outputs of the detection means, 53 is a quality comparator for comparing the quality results output from the identification timing quality estimators 51 and 52, and 10 is a result. Is a selector for switching the detection signals of the two branches.

The operation of the diversity receiver constructed as above will be described. First, the modulated waves received through the different paths are input to the respective branches of the receiver. The input signal becomes a desired detected signal by appropriately converting the frequency and band limitation by the RF and IF units 3 and 4, and is detected by the detectors 7 and 8. Detector 7,
In No. 8, in addition to the angle information detection mechanism for reproducing the transmission data signal, a mechanism for generating the identification timing is required. The estimation of the identification timing is performed by the amplitude of the modulation signal,
The repetition period is extracted by using properties such as the phase.In general, in the case of digital modulation, the symbol period is extracted by some method and then stabilized and identified by a narrow band filter. It is generally used as a signal.

When applying such a timing estimation mechanism to a communication line in which abrupt fluctuations of a transmission line due to multipath fading or the like may occur, a problem arises.
The abrupt fluctuations in the received wave level and phase may cause the received signal in a certain branch to be of a quality that can hardly be reproduced correctly. In such a situation, the signal of this branch is meaningless even if it is selected, which leads to an increase in error rate.In order to avoid such a situation, in the conventional example, the one with a higher reception level is used. Select a branch. Alternatively, the branch having the higher phase reduction is selected so as to improve the quality.

However, since it is difficult to obtain a sufficient diversity effect by simply selecting the one having a high signal quality due to the deterioration of the reproduction of the identification timing, in the present embodiment, the identification timing quality estimators 51 and 52 are provided. The information from the reproduction of the identification timing is obtained by the above, and the quality thereof is monitored, and the selector 1
By switching the detection output by 0, an excellent effect can be obtained in that the switching diversity device can be realized in the form including the discrimination timing of the received modulated signal.

As described above, according to this embodiment, the identification timing quality estimators 51 and 52 for monitoring the quality of the identification clock in the identification timing reproduction of the reception detectors 7 and 8 are provided, and the situations of the respective branches are compared. As a result, a good diversity receiver can be provided.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram of a diversity receiver in the second embodiment of the present invention.

In FIG. 2, the difference from the first embodiment in FIG. 1 is that an identification timing quality estimator 5 for monitoring the quality of the identification timing as a means for selecting a branch.
In addition to Nos. 1 and 52, conventionally used comparison elements represented by the level detectors 31 and 32 for the reception RF and IF units 3 and 4 are also used.

According to the above construction, the basic operation is the same as that of the first embodiment, but in this embodiment, the selector 54 comprehensively judges the detection signals of the comparison elements to perform branch selection. .

Although the reception level is assumed in the present embodiment as the comparison element by the level detectors 31 and 32, the phase degree of the detected signal may be used. Needless to say, these may be used in combination.

As described above, according to the present embodiment, in addition to the comparison of the identification timing signals in each branch, level detectors 31 and 32 for detecting different comparison elements are also used, and a comparison for comprehensive comparison is made. By providing the device 54, it is possible to further improve the reception quality.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a block diagram of a diversity receiving apparatus according to the third embodiment of the present invention.

In FIG. 3, reference numerals 61 and 62 are identification timing quality predictors for monitoring and predicting the quality of the identification timing recovered clock, and 63 is a predicted value for comparing the predicted values to determine a selection criterion from the present situation to the future. Comparator, 64
Is the detection outputs 13 and 14 which are the outputs of the detectors 7 and 8 and the data clocks 15 and 1 generated from the identification timing.
6 is a selector that selects 6 based on a predicted value comparator.

In the diversity receiver constructed as described above, the basic operation is the same as that of the first embodiment, but first, in the generation of the identification timing due to the abrupt change of the transmission line, multipath fading or the like is performed. It is fully predicted that the timing degradation due to the above may occur, and it is highly conceivable that this effect reduces the diversity effect.

In such a case, the identification timing quality predictors 61 and 62 monitor and predict the identification timing to prevent the diversity effect from decreasing.

The prediction in the present embodiment is performed by monitoring the timing variation and appropriately monitoring the displacement from the steady state and the speed to predict the rapid timing fluctuation, and when the timing slip is likely to occur. By removing the branch from the selection target, it is possible to prevent the decrease in the diversity effect. In addition, it is possible to avoid the inconsistency of the permutations of the data signals due to the timing shift due to this deterioration and increase the margin.

[0031]

As described above, according to the first aspect of the present invention, the quality of the identification clock obtained by the identification timing recovery mechanism of the detection unit of each branch is improved when the diversity angle reception is performed in the receiver of the digital angle modulated wave. By providing the monitoring means, it is possible to realize an excellent diversity receiving method capable of preventing the characteristics of the selected branch from being deteriorated due to the large deterioration of the identification clock caused by the rapid fluctuation of the transmission path. .

Secondly, when switching the identification timing itself, by providing means for predicting the degree of deterioration in the selection of the identification clock in advance, inconsistency in the switching timing is avoided and a margin is set. It is possible to realize an excellent diversity reception method that can be increased.

[Brief description of drawings]

FIG. 1 is a block connection diagram of a diversity receiver according to a first embodiment of the present invention.

FIG. 2 is a block connection diagram of a diversity receiver according to a second embodiment of the present invention.

FIG. 3 is a block connection diagram of a diversity receiver according to a third embodiment of the present invention.

FIG. 4 is a block connection diagram of a conventional diversity receiver.

FIG. 5 is a block connection diagram of a conventional diversity receiver.

[Explanation of symbols]

 3, 4 reception RF, IF section 7, 8 detector 9 level comparator 10 detection output switcher 31, 32 level detector 41, 42 phase accuracy estimator 43 accuracy comparator 44 accuracy, level comparator 51, 52 identification timing quality determiner 53 quality comparator 54 quality and level comparator 61, 62 identification timing quality predictor 63 predictive value comparator

Claims (2)

[Claims] 1. A detection means for respectively detecting a plurality of branches received by receiving a digital angle modulated wave,
A plurality of identification timing quality estimating means for estimating the quality of the identification timing based on the detection result of the detecting means, a quality comparing means for comparing the quality of the output of the identification timing quality estimating means, and a comparison result of the quality comparing means A diversity receiving apparatus comprising: a selection unit that switches detection signals by the detection unit of the branch. 2. Detection means for respectively detecting a plurality of branches received by receiving the digital angle modulated wave,
A plurality of identification timing quality estimating means for estimating the quality of the identification timing based on the detection result of the detecting means, a quality comparing means for comparing the quality of the output of the identification timing quality estimating means, and a comparison result of the quality comparing means A diversity receiving device comprising a detection signal for switching the detection signal and the identification timing signal by the detection means of the branch.