JPH09219672A - Radio communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a proper data weight value even when the same channel interference exists for the output signals of plural receivers, in a radio communication equipment performing a diversity reception. SOLUTION: An S/N measuring device 22 determines an S/N from receiver outputs R1 and R2. From the S/N, the error rates P1 and P2 of demodulator outputs D1 and D2 and right answer rates 1-P1 and 1-P2 are calculated. A correlation device 21 determines the correlation values C1 and C2 of the receiver outputs R1 and R2 and a specified pattern signal when the specified pattern signal is transmitted by a transmission side. A weight value output part 23 determines the weight values ω1, ω2; ω1*, ω2* for demodulator output data D1 and D2 and the opposite polarity data D1* and D2<2> * from the outputs of the S/N measuring device 22 and the correlation device 21. A majority deciding device calculates the total of the weight values corresponding to '0' data and the total of the weight values corresponding to '1' data of the data D1, D2, D1* and D2*. The data of the larger total ('0' or '1') is decided as right data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication device that performs bidirectional communication and performs diversity reception using weighted majority decision.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional wireless communication device (K. Ishioka,
H.Takanashi and T.Tanaka, “Improved Throughput Ch
aracteristics by ARQ with Weighted Majority Decisi
on ”, Proc.of the 4th IEEE 1995.), where 11 and 12 are antennas, 13 and 14 are receivers,
Reference numerals 5 and 16 are demodulators, 17 is a data weight value calculator by an S / N measuring device, 18 is a majority decision device, and 19 is an output device.

In FIG. 6, the signal received by the antenna 11 is detected by the receiver 13, and its output R1 is input to the data weight value calculator 17, where the weight value of the received data is calculated and demodulated. The demodulator 15 demodulates the binary reception data D1. Further, the radio signal received by the antenna 12 is detected by the receiver 54, and its output R2 is S / N.
It is input to the data weight value calculator 17 using a measuring device, the weight value of the received data is calculated, and the demodulator 16
Is demodulated into binary reception data D2.

FIG. 7 shows a data weight value calculator 17 using an S / N measuring device. Output signals R1 of the receivers 13 and 14
R2 is input to the data weight value calculator 17, and the built-in S /
The reception state at the time of signal reception is evaluated using the output of the N measuring device, and the weight values ω1 and ω2 for the demodulated reception data D1 and D2 and the opposite polarity value D1 ^{* of} the reception data D1 and D2, the weight of the value for the D2 ^* ω1 ^*, ω2 ^*
Is calculated. In the data weight value calculator 17, the received signal R
The powers obtained by subtracting the average thermal noise powers generated in the receivers 13 and 14 from the powers 1 and R2 and the receivers 13 and 14, respectively.
The ratio of the average thermal noise power generated in the above is calculated, and the obtained S / N is substituted into the theoretical formula of the bit error rate peculiar to the modulation system, and the received data D1 demodulated for each antenna system
The error rates P1 and P2 of D2 and the correct answer rate (1-P1),
Calculate (1-P2). Demodulated reception data D1, D
Weight values ω1 and ω2 for 2 and the received data D
1, the opposite polarity value of D2 D1 ^*, D2 weight value .omega.1 ^* for ^*, the correct answer rate of the received data D1, D2 as ω2 ^* (1-P1), is (1-P2) and the error rate P1, P2 They are used respectively and output from the data weight value calculator 17.

The majority decision device 18 stores the demodulated reception data D1 and D2 and the opposite polarity values D1 ^* and D2 ^* of the reception data, and also demodulates the reception data D1 from the data weight value calculator 17. , Ω2 corresponding to D2, D2 and their received data D1, D2
Value ω corresponding to the opposite polarity values D1 ^* and D2 ^* of
1 ^* , ω2 ^* are stored, the received data D1, D2 and the opposite polarity values D1 ^* , D2 ^* of the received data are weighted to demodulate the received data D1, D2 and the opposite polarity of the received data. Of the values D1 ^* and D2 ^* of the above, the sum of the weight values corresponding to the “0” data and the sum of the weight values corresponding to the “1” data are calculated, and the data with the larger total is calculated. ("0" or "1") is determined as correct data and sent to the output device.

The output device 19 outputs the judgment value of the received data obtained from the majority judgment device.

[0007]

In the conventional radio communication apparatus as described above, when the radio signals received by the plurality of receivers include the interference signal due to the co-channel interference, the data weight value calculator 17 When the reception state at the time of signal reception is evaluated only by the output of the S / N measuring device, the weight values corresponding to the demodulated reception data D1 and D2 and the opposite polarity values D1 ^* and D2 ^* of the reception data are obtained. There is a problem that ω1, ω2 and ω1 ^* , ω2 ^* cannot be calculated properly.

For example, in the data weight value calculator 17 of FIG. 6, in order to properly measure S / N by the S / N measuring device, when the desired wave power is D and the interference wave power is U,
D / (U + N) should be measured, but if the radio signals received by the plurality of receivers include interference signals due to co-channel interference, the reception signals R1, detected by the plurality of receivers, Since R2 is a combination of a desired signal and an interference signal due to co-channel interference, (D + U)
/ N will be measured. Therefore, the reception state at the time of signal reception cannot be properly evaluated only by the output of the S / N measuring device, and the demodulated reception data D1 and D2 and the opposite polarity values D1 ^* and D2 ^{* of the} reception data ^. The weight values ω1, ω2 and ω1 ^* , ω2 ^* corresponding to can not be calculated properly.

The present invention has been made in view of such conventional problems.
In addition to the signal-to-noise ratio (S / N) obtained for each receiver, the reception condition at the time of signal reception by a plurality of receivers,
The purpose is to calculate an appropriate weight value of demodulated data by evaluating the correlation value between the output signal of each receiver and the specific pattern when the specific pattern is inserted on the transmitting side.

[0010]

[Means for Solving the Problems]

(1) A wireless communication apparatus according to claim 1, wherein a plurality of antennas, receivers respectively connected to the antennas, demodulators for demodulating outputs of these receivers, and outputs (R) of each receiver.
1, R2), S / N is calculated, and the error rate (P1, P2) and correct answer rate (1-P1, 1-P2) of each demodulator output (D1, D2) are calculated from the S / N. N measuring device, a correlator for obtaining a correlation value (C1, C2) between the output (R1, R2) of each receiver when the signal of the specific pattern is transmitted on the transmitting side, and S / Error rate (P1, P2) and correct answer rate (1-P
1,1-P2) and the correlation value (C1,
C2), the weight values (ω1, ω2) for the demodulator output data (D1, D2) and the weight values (ω1 ^* ) for the data (D1 ^* , D2 ^* ) having the opposite polarity to the demodulator output data ^. , Ω2 ^* ), and the output data (D1, D2) of the demodulator and the data (D1 ^* , D2 ^* ) of the opposite polarity to the output data, which corresponds to “0” data. A majority decision unit for calculating the sum of the weight values and the weight values corresponding to the data of "1" and determining the data with the larger sum ("0" or "1") as correct data. , Are provided.

(2) The invention of claim 2 is based on the above (1).
Then, the weight value output section displays the demodulator output data (D1, D
2) As the weight values (ω1, ω2), the demodulator output data
Multiply value of the correct answer rate of the data and the correlation value corresponding to each demodulator
[(1-P1) C1, (1-P2) C2] is calculated. Ma
Data of the opposite polarity to the demodulator output data (D1^*, D
2 ^*) Weight value (ω1^*, Ω2^*) As each demodulator
Of the output data error rate and the correlation value corresponding to each demodulator
The multiplication value [P1C1, P2C2] is obtained.

According to the present invention, the receiving condition at the time of receiving signals by a plurality of receivers is not evaluated only by the signal-to-noise ratio (S / N) obtained for each receiver, but each receiver is evaluated. In addition to the signal-to-noise ratio (S / N) obtained for
This is different from the prior art in that it is evaluated by the correlation value between the output signal of each receiver when a specific pattern is inserted on the transmitting side and the specific pattern. Due to this difference, the invention of claim 1 can know the level information of the desired wave included in the radio signal received by the plurality of antennas, and is reflected in the evaluation of the reception state when the signals are received by the plurality of receivers. Therefore, it is possible to correctly judge the received data in the majority judgment device.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the embodiment shown in FIG. In FIG. 1, parts corresponding to those in FIG. 6 are designated by the same reference numerals. 11 and 12 are antennas and 13 and 1
4 is a receiver, 15 and 16 are demodulators, 17 is a data weight value calculator that evaluates the reception state at the time of signal reception and calculates the weight value of the received data, 18 is the majority decision, and correct data is determined Numeral 19 is an output device for outputting the decoded data.

FIG. 2 is a block diagram of the data weight value calculator 17 of FIG. The data weight value calculator 17 uses the correlator 2
1 and the S / N measuring device 22 and the weight value output unit 23. The data weight value calculator 17 inputs the output signals R1 and R2 of the receiver to the correlator 21 and the S / N measuring device 22, respectively, evaluates the reception state at the time of signal reception from the respective outputs, and demodulates them. The value of the weight of the received data is calculated.
The correlator 21 correlates the output signals R1 and R2 of a plurality of receivers with the signal of the specific pattern by utilizing the fact that a signal of a specific pattern, for example, a unique word is inserted on the transmission side. , Correlation values C1 and C2 are output. Based on the correlation value obtained here, the level information of the desired wave contained in the output signal of the receiver can be obtained.

On the other hand, the S / N measuring device 22 calculates and outputs the ratio of the power obtained by subtracting the average thermal noise power generated in the receiver from the power of the received signal and the average thermal noise power generated in the receiver. Substituting the S / N obtained here into the logical expression of the bit error rate peculiar to the modulation method, the error rates P1 and P2 of the received data D1 and D2 to be demodulated and the correct answer rate (1-P
1) and (1-P2) are calculated. In the weight value output unit 23, the weight value ω for the output data D1 and D2 of the demodulator
1, ω2 and the value D of the opposite polarity of the output data
1 ^*, D2 weighting value .omega.1 ^* of for ^*, .omega.2 ^* is the correlator and the correlation values C1, C2 obtained by the 21, the correct answer rate obtained by the S / N measuring device 22 (1-P1), ( 1 -P
2) and the error rates P1 and P2, and ω1 = (1−P1) C1 and ω2 = (1−P2) C
2; ω1 ^* = P1C1 and ω2 ^* = P2C2 are obtained.

FIG. 3 shows the configuration of the correlator 21 in FIG. The correlator 21 is composed of a coefficient multiplier and a delay circuit. In the correlator 21, the received signal R
To the delay circuit to prepare time series r0 to rn-1. Next, the time series r0 to rn-1 and the time series r0
.About.rn-1 are multiplied by the coefficients k0 to kn-1, and the multiplication results are S0 to Sn-1. Further, the multiplication results S0 to Sn-1 are added and output as the correlation value C. Here, the coefficients k0 to kn corresponding to the time series r0 to rn-1
By using a unique word as -1, the correlation value C between the received signal R and the unique word can be obtained. Therefore, when the received signals R having different levels are input, the correlation value C becomes an output proportional to the level of the desired wave included in the received signal. Therefore, when a plurality of signals are received, the level ratio of the part corresponding to each unique word can be known from the correlation value.

The majority decision device 18 stores the demodulated reception data D1 and D2 and the opposite polarity values D1 ^* and D2 ^* of the reception data, and also demodulates the reception data D1 from the data weight value calculator 17. , D2 corresponding to the weight values ω1 and ω2, and the opposite polarity values D1 ^* and D2 ^* of the received data, the weight values ω1 ^* and ω2.
^* Is stored, and the demodulated reception data D1 and D2 and the data D1 ^* and D2 ^* of the opposite polarity of the reception data are weighted to receive the reception data D1 and D2 and the data D1 ^* of the opposite polarity of the reception data ^. , D2 ^* , the sum of the weight values corresponding to the “0” data and the sum of the weight values corresponding to the “1” data are calculated, and the data with the larger sum (“0”) is calculated. Alternatively, "1") is determined to be correct data and sent to the output device.

The output device 19 outputs the judgment value of the received data obtained from the majority judgment device 18. Hereinafter, the operation of the data weight value calculator 17 will be described in more detail. FIG. 4 shows the data weight value calculator 17 of FIG.
Output signals R of a plurality of receivers obtained by the correlator 21
Correlation values C1 and C2 corresponding to 1 and R2 and output data D1 and D of the plurality of demodulators obtained by the S / N measuring device 22.
2 error rates P1, P2 and correct answer rates (1-P1), (1
-P2) is an example of a numerical value. In FIG. 3, the number of antenna systems is set to 2, and the judgment output by the demodulator is inverted by the systems of antennas 1 and 2, and the judgment output D1 of the system of antenna 1 is "1" and the judgment output of the system of antenna 2 D2 is 0. Also, the received signal R detected by the two receivers
1 and R2, the system side of the antenna 1 has a higher level (R1> R2), and the average thermal noise power generated in the receiver is the same in each antenna system. Further, the level of the desired wave included in the received signals R1 and R2 is higher on the system side of the antenna 2. At this time, the correct received data value is that the received signal R2 detected by the receiver on the antenna 2 side is the received signal R1 on the system side of the antenna 1
Since the desired wave is included more than the desired wave, the value of the reception data demodulated on the system side of the antenna 2 is set to "0".

In the S / N measuring device 22, of the received powers obtained by the two antennas, the received power on the system side of the antenna 1 becomes larger (R1> R2), and the S / N for the system of the antenna 1 is increased. γ1, S / N for the system of antenna 2 is γ
If the value is 2, the average thermal noise power generated in the receiver is the same in each antenna system, so that the relationship of γ1> γ2 is established. Therefore, from the relation of γ1> γ2, the error rates P1 and P2 of the received data demodulated in each antenna system obtained from the theoretical equation of the bit error rate peculiar to the modulation method are
<P2, where P1 is 0.2 and P
Let 2 be 0.3.

On the other hand, in the correlator 21, the received signal R
1 and R2 are input to the correlator 21 and are correlated with the unique word. Since the levels of the desired waves included in the received signals R1 and R2 are higher on the system side of the antenna 2, the output values C1 and C2 of the correlator have a relationship of C1 <C2. Here, when the system side of antenna 1 is C1 = 1, antenna 2
The system side of C2 = 2.

Under the conditions of FIG. 4, in the data weight value calculator 17 of the conventional radio communication apparatus, the majority decision unit 18 evaluates the reception state at the time of signal reception only by the output of the S / N measuring unit. Data D1, D2, D1 ^* , D2
^{Of the *} , the sum of the weight values for the “1” data is (1
-P1) + P2 = 0.8 + 0.3 = 1.1 and "0"
Sum of the weight values for the data of P1 + (1-P
2) = 0.2 + 0.7 = 0.9 is calculated. Therefore, the relationship "total of weight values for data" 1 "">"total of weight values for data" 0 "" is established, and the result of the majority decision is erroneously determined to be "1".

However, under the condition of FIG. 4, in the present invention, the sum of the weight values for the data "1" is (1-P
1) C1 + P2C2 = 0.8 × 1 + 0.3 × 2 = 1.4
And the sum of the weight values for the data “0” is P1C
1+ (1-P2) C2 = 0.2 × 1 + 0.7 × 2 = 1.
Calculated as 6. Therefore, the relation of “sum of weight values for data“ 1 ”” <“sum of weight values for data“ 0 ”” is established, and the result of the majority decision can be correctly determined as “0”.

FIG. 5 is a diagram showing the simulation result of the bit error rate of the device of FIG. 1 in comparison with the device of FIG. The specifications of the simulation are described below. The modulation / demodulation method is π / 4-QPSK differential detection with a transmission rate of 38.
The frequency was 4 kbps, the fading was flat Rayleigh, and the Doppler frequency was 10 Hz. The number of antenna systems is set to 3, and the period 31-M series is used as a unique word. In FIG. 5, the desired wave-to-interference wave power ratio CIR = 10d
The calculation examples at B, 15 dB, and 20 dB are shown. According to the invention, as seen in this figure, CIR =
At 15 dB, the required Eb / NO (Eb is signal energy per bit, NO is noise power density per hertz) at a bit error rate (BER) of 10 ^-2 is 3d.
B and CIR = 20 dB, the required Eb / NO at the bit error rate of 10 ⁻³ can be improved by 4 dB.

[0024]

As described above, according to the present invention, the reception state at the time of signal reception by a plurality of receivers can be obtained by comparing the signal-to-noise ratio (S / N) obtained for each receiver with the transmission side. In the majority decision by evaluating the output signals of a plurality of receivers when a specific pattern is inserted and the correlation value between the specific pattern and calculating the value of the weight of the received data. It is possible to properly calculate the weighted value corresponding to the demodulated received data used when executing and the value of the opposite polarity of the received data even when the output signal of each receiver has co-channel interference. There are advantages.

Further, the wireless communication device of the present invention is, as compared with the conventional wireless communication device, as shown in the embodiment,
There is also an advantage that the bit error rate can be greatly improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram of a data weight value calculator 17 of FIG.

FIG. 3 is a block diagram of a correlator 21 shown in FIG.

4 is a diagram showing a numerical example of output data of the S / N measuring device 22 and the correlator 21 of FIG.

5 is a diagram showing a simulation result of a bit error rate of the device of FIG.

FIG. 6 is a block diagram of a conventional wireless communication device.

FIG. 7 is a block diagram of a data weight value calculator using a conventional S / N measuring device.

Claims (2)

[Claims] 1. A plurality of antennas, receivers respectively connected to the antennas, demodulators for demodulating outputs of the receivers, and S / N from outputs (R1, R2) of the receivers. Seeking
Error of each demodulator output (D1, D2) from the S / N
Rate (P1, P2) and correct answer rate (1-P1,1-P2)
S / N measuring device for calculation and each of the above when a signal of a specific pattern is transmitted from the transmitting side
The output of the receiver (R1, R2) and the signal of the specific pattern
Correlator for obtaining the correlation value (C1, C2) with the signal, and the error rates (P1, P2) and
And correct answer rate (1-P1,1-P2), and obtained from the correlator
The output of the demodulator from the obtained correlation values (C1, C2)
Weight values (ω1, ω2) for the data (D1, D2)
And data having a polarity opposite to that of the output data of the demodulator (D
1^*, D2^*) Value of weight (ω1 ^*, Ω2^*)
A weight value output unit to be obtained, output data (D1, D2) of the demodulator and its output data
Data with the opposite polarity to the data (D1^*, D2^*) Of
The sum of the weight values corresponding to the data of "0" and "1"
Calculate the sum of the weight values corresponding to
The data with the larger sum of (0 or 1) is positive
A majority decision device for judging that the data is new
A wireless communication device. 2. The correctness rate of each demodulator output data and each demodulation as the weight value output unit as a weight value (ω1, ω2) of the demodulator output data (D1, D2) according to claim 1. Value multiplied by the correlation value [(1-
P1) C1, (1-P2) C2], and data (D1 ^* ,
As a weight value (ω1 ^* , ω2 ^* ) of D2 ^* ), a multiplication value [P1C1, P2C2] of the error rate of the output data of each demodulator and the correlation value corresponding to each demodulator is obtained. Wireless communication device.