JP3421094B2 - Decoding method and decoding device for coded modulation signal - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for receiving and decoding a coded modulation signal transmitted from a transmitter via an environment where fading exists.

[0002]

2. Description of the Related Art Generally, in a mobile communication system in which severe multipath fading is present, when digital transmission is performed, the electric field strength level of a received signal often drops below the thermal noise level of the receiver due to fading. Its bit error rate (BER) characteristic is significantly degraded.

In order to improve the deterioration of the bit error rate characteristic, the error correction coding and the multi-level modulation system are combined,
By using a part of the transmission bits per radio pulse increased by multi-level modulation as redundant bits for error correction, it is possible to improve the transmission characteristics without increasing the bandwidth. Application is under consideration.

In this case, when the receiver receives the coded modulated signal sent from the transmitter via the environment where fading exists, the receiver decodes the coded modulated signal. Upon decoding, the complex amplitude fluctuation due to fading is estimated, and then the coded modulated signal is decoded by using the estimated complex amplitude fluctuation and the received coded modulated signal.

More specifically, at the time of decoding, a decision variable corresponding to each code word of the coded modulation signal is calculated by using the estimated complex amplitude fluctuation and the received coded modulation signal,
By comparing the obtained decision variables, the smallest decision variable is selected as the decoding information of the coded modulated signal. Next, the calculation method of the decision variable will be further described as follows.

First, the estimated value hh _m of the received signal r _m and the complex amplitude fluctuation of fading can be expressed by the following equation. In addition, when notating the estimated value, the symbol h is also added to the head of the symbol as described above, but in the formula,
Note that the hut symbol may be used to represent the estimate without the h mark.

[0007]

[Equation 3]

Where z _m is an additive white noise component, ε _m
Represents the estimation error component of the fading complex amplitude variation. Further, z _m is a statistically independent Gaussian random variable having mean 0, variance N ₀ / 2Es, and ε _m having mean 0, variance rN ₀ / 2Es. r is the variance of the estimation error of the fading complex amplitude variation normalized by the variance of the additive white noise component.

Therefore, the decision variable of the conventional coded modulation scheme under fading is expressed by the following equation.

[0010]

[Equation 4]

Then, the receiver determines that the codeword sequence Vs ⁽ⁱ⁾ (vector) that minimizes this determination variable has been transmitted. It should be noted that, in the case of expressing a vector, the V mark is added to the head of the symbol as described above also in the following, but it should be noted that the vector symbol may be used without the V mark in the formula.

When hh _m can be estimated without error, that is, when hh _m = h _m holds, it means that the maximum likelihood sequence judgment is performed by using this judgment variable. The above method is the optimal decoding method.

[0013]

By the way, when applying the above-described coded modulation method to a fading communication channel,
As described above, it is necessary to estimate the complex amplitude variation of the received signal due to fading. As a method of estimating the complex amplitude variation, a method of inserting a known pilot signal into the transmission signal is being studied. However, even with such a method, it is impossible to accurately estimate the amplitude fluctuation.

Further, in the above method, the decoding is performed assuming that the estimated value of the fading complex amplitude fluctuation has no error, and no countermeasure against the estimation error has been studied. Therefore, the estimation of the fading complex amplitude fluctuation is performed. There is a problem that the bit error rate characteristic is deteriorated due to the existence of an error in the value. The present invention was devised in view of such a problem, and it is possible to reduce the deterioration of the error rate characteristic due to the estimation error of the fading complex amplitude fluctuation, and improve the quality of digital transmission in a fading channel. An object of the present invention is to provide a decoding method and a decoding device for a coded modulation signal.

[0015]

FIG. 1 is a block diagram of the principle of the present invention. In FIG. 1, 101 is an estimating means, and this estimating means 101 estimates a complex amplitude fluctuation due to fading. A decoding unit 102 uses the complex amplitude fluctuation estimated by the estimating unit 101 and the received coded modulation signal, and performs a weighting process according to the magnitude of the estimation error of the complex amplitude fluctuation. The judgment corresponding to each code word of the code-modulated signal obtained by applying
The coded modulation signal is decoded based on a constant variable .

In this case, the decoding means 102 is the estimation means 1
The complex amplitude fluctuation estimated in 01 and the received coded modulation signal are input, and these signals are used, and by performing a weighting process according to the magnitude of the estimation error of the complex amplitude fluctuation, the coded modulation is performed. A plurality of decision variable calculation means 1031 to 103n for calculating the decision variable corresponding to each code word of the signal
(N is a natural number) and each of the judgment variable calculation means 1031-10
Selection means 10 that compares the decision variables obtained in 3n and selects the smallest decision variable as the decoding information of the coded modulated signal.
It is configured with 4.

Then, the decision variable calculating means 1031-10
3n uses the complex amplitude fluctuation estimated by the estimation means 101 and the received coded modulation signal as input information,

[0018]

[Equation 5]

It may be configured to output a decision variable corresponding to the codeword of the coded modulated signal by calculating. At this time, the judgment variable calculation means 1031 to 103n
Is a matrix operation means for linearly converting the complex amplitude fluctuation and the reception coded modulation signal estimated by the estimation means 101 using the covariance matrix of the reception coded modulation signal; and the complex amplitude fluctuation estimated by the estimation means 101, The product information of the complex conjugate calculation means for calculating the complex conjugate of the received coded modulation signal, the complex amplitude fluctuation linearly converted by the matrix calculation means, and the complex conjugate information of the complex amplitude fluctuation obtained by the complex conjugate calculation means is obtained. And a multiplication means for obtaining product information of the reception coded modulation signal linearly converted by the matrix calculation means and the complex conjugate information of the reception coded modulation signal obtained by the complex conjugate calculation means. Further, it comprises an adding means for adding the two pieces of product information, and an integrating means for integrating the output from the adding means and outputting it as a decision variable corresponding to the codeword.

Further, the judgment variable calculation means 1031 to 103
n is the complex amplitude fluctuation estimated by the estimation means 101 and the received coded modulation signal as input information,

[0021]

[Equation 6]

It may be configured to output a decision variable corresponding to the codeword of the coded modulated signal by calculating. At this time, the judgment variable calculation means 1031 to 103
n multiplies the replica signal generation means for generating a replica signal of the coded modulation signal sent from the transmission device, the replica signal generated by the replica signal generation means, and the complex amplitude fluctuation estimated by the estimation means. The first multiplication means, the inter-signal distance calculation means for calculating the inter-signal distance from the output from the first multiplication means and the received coded modulation signal, and the complex signal based on the replica signal generated by the replica signal generation means. Second weighting means for computing weighting information according to the magnitude of the estimation error of the amplitude variation, weighting information from the weighting means, and output from the inter-signal distance computing means
It comprises a multiplication means and an integration means for integrating the output from the second multiplication means and outputting it as a decision variable corresponding to the codeword.

[0023]

In the present invention described above, the estimating means 101 estimates the complex amplitude fluctuation due to fading, and then the decoding means 1
02, the code modulation obtained by using the complex amplitude fluctuation estimated by the estimation means 101 and the received coded modulation signal, and by performing weighting processing according to the size of the estimation error of the complex amplitude fluctuation . The code corresponding to each codeword of the signal
The coded modulated signal is decoded based on the constant variable .

In this case, in the decoding means 102, the plurality of decision variable calculating means 1031 to 103n input the complex amplitude fluctuation estimated by the estimating means 101 and the received coded modulation signal, and use these signals, and , A decision variable corresponding to each codeword of the coded modulated signal is calculated by performing a weighting process according to the magnitude of the estimation error of the complex amplitude fluctuation, and the selection means 104 further calculates each decision variable calculation means 1031. Comparing the judgment variables obtained in ˜103n,
The smallest decision variable is selected as the decoding information of the coded modulation signal.

Then, each judgment variable calculation means 1031 to 1
In 03n, the complex amplitude fluctuation estimated by the estimation means 101 and the reception coded modulation signal are used as input information, and the above (4)
The decision variable corresponding to the codeword of the coded modulated signal is output by calculating the expression, or the decision variable corresponding to the codeword of the coded modulated signal is output by calculating the above equation (5). .

Here, when the above equation (4) is calculated,
In the decision variable calculation means 1031 to 103n, the matrix calculation means linearly transforms the complex amplitude fluctuation and the reception coded modulation signal estimated by the estimation means 101 using the covariance matrix of the reception coded modulation signal, and the complex conjugate. The calculation means calculates the complex amplitude fluctuation estimated by the estimation means 101 and the complex conjugate of the received coded modulated signal, and the multiplication means calculates the complex amplitude fluctuation linearly converted by the matrix calculation means and the complex conjugate calculation means. The product information of the obtained complex amplitude variation and the complex conjugate information is obtained, and the received coded modulated signal linearly converted by the matrix calculating means and the complex conjugate information of the received coded modulated signal obtained by the complex conjugate calculating means. And the product information obtained by the multiplying device is added by the adding device, and the output from the adding device is integrated by the integrating device to obtain the decision variable corresponding to the code word. It is performed to and output.

Further, in the case of calculating the above equation (5), in each of the decision variable calculating means 1031 to 103n, the replica signal generating means generates the replica signal of the coded modulated signal sent from the transmitter, and The 1 multiplication unit multiplies the replica signal generated by the replica signal generation unit by the complex amplitude fluctuation estimated by the estimation unit 101. Further, the inter-signal distance calculating means calculates the inter-signal distance from the output from the first multiplying means and the received coded modulated signal. At this time, the weight calculation means calculates weight information according to the magnitude of the estimation error of the complex amplitude fluctuation based on the replica signal generated by the replica signal generation means, and then the second multiplication means calculates the weight information. Weight information from the weight calculation means,
The output from the inter-signal distance calculation means is multiplied, and the integration means further integrates the output from the second multiplication means and outputs the result as a decision variable corresponding to the code word.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. Now, the wireless communication system to which the present invention is applied,
As shown in FIG. 2, the transmitter 1 and the receiver 2 are provided, and the receiver 2 receives the coded modulated signal transmitted from the transmitter 1 via the environment where fading exists. It is designed to be decrypted.

First, as shown in FIG. 3, the transmitter 1 comprises a serial / parallel converter 11, a codebook 12, digital / analog converters 13 and 14, and an orthogonal converter 15. Here, the serial-parallel converter 11 converts an input binary sequence signal into K-bit (K is a natural number) parallel data Vb ⁽ⁱ⁾ , and the codebook 12 is composed of a ROM and has N symbols (N is a natural number). ) Block coded modulation method (Block Coded
Modulation: BCM) code word sequence Vs ⁽ⁱ⁾ .

The code word sequence Vs ⁽ⁱ⁾ is an N-dimensional complex vector defined by the following equation. Vs ⁽ⁱ⁾ = _{^{[s 1 (i), ····,}} s N (i) ] ^T ... (6) where, i is 0, ..., a M-1. Further, T means transposition, and M = 2 ^K represents the number of code words. Further, the digital / analog converters 13 and 14 perform analog conversion of the digital codeword sequence converted by the codebook 12, and the orthogonal converter 15 is a digital / analog converter 1.
It receives the signals from 3 and 14 and outputs a coded modulated signal.

Therefore, in the transmitter 1, the input binary sequence is converted by the serial-parallel converter 11 into K-bit parallel data Vb ^(i), and this data Vb ⁽ⁱ⁾ is further composed of a codebook composed of a ROM. 12 and is converted into a code word sequence Vs ⁽ⁱ⁾ of the N symbol block coding modulation method. Further, the code word sequence Vs ⁽ⁱ⁾ is converted into an analog value by the digital / analog converters 13 and 14, and further converted into a radio frequency modulated wave by the quadrature modulator 15 and transmitted.

After that, each symbol of Vs ⁽ⁱ⁾ is distorted by fading and white Gaussian noise and is received by the receiver 2. The receiver 2 receives from the transmitter 1 in an environment where fading exists. As shown in FIG. 4, in order to receive and decode the coded modulated signal sent via the quadrature detector 21, analog / digital converters 22, 23, complex amplitude fluctuation estimator 24, decoder 25 are provided.

Here, the quadrature detector 21 is for quadrature detecting the received signal, and the analog / digital converter 22,
Reference numeral 23 is for digitally converting the analog quadrature detection signal. The complex amplitude fluctuation estimator 24 estimates the complex amplitude fluctuation due to fading based on the digitized quadrature detection signal.

The decoder 25 uses the complex amplitude fluctuation estimated by the complex amplitude fluctuation estimator 24 and the quadrature detection signal, and performs weighting processing according to the magnitude of the estimation error of the complex amplitude fluctuation. By doing so, the coded modulated signal is decoded. For this reason, the decoder 25, as shown in FIG. 5, has a plurality (n) of decision variable calculators 31 to 3n.
And a comparison / determination unit 41.

Here, the decision variable calculators 31 to 3n receive the complex amplitude fluctuation estimated by the complex amplitude fluctuation estimator 24 and the received coded modulation signal, use these signals, and calculate the complex amplitude fluctuation. The decision variable corresponding to each code word of the coded modulated signal is calculated by performing the weighting process according to the size of the estimation error of. Further, the comparison / determination unit 41 compares the determination variables obtained by the respective determination variable calculation units 31 to 3n and selects the smallest determination variable as the decoding information of the coded modulation signal.

Therefore, in the receiver 2, the received signal is quadrature detected by the quadrature detector 21, and the baseband received signal r _m is obtained. The baseband received signal is converted into a digital value by the analog / digital converters 22 and 23 and input to the complex amplitude fluctuation estimator 24 and the decoder 25. Then, the complex amplitude fluctuation estimator 24, estimate hh _m of the complex amplitude fluctuation h _m fading is estimated, the estimated value hh _m is input to the decoder 25.

In the decoder 25, the estimated value of the fading complex amplitude fluctuation and the baseband received signal are input to the decision variable calculation units 31 to 3n corresponding to the codeword of the coded modulation that can be output in the codebook 12. A decision variable corresponding to each codeword is obtained. The present invention is characterized in how to determine the decision variables in the decision variable calculation units 31 to 3n, which will be described later in detail.

Then, the comparison / determination unit 41 compares the sizes of the determination variables, and determines that the binary sequence corresponding to the codeword having the smallest determination variable value is transmitted from the transmitter 1. By the way, the judgment variable calculation unit 31 which is a feature of the present invention
How to obtain the judgment variable in 3n will be described in detail below. Now, the three-dimensional column vector Vx _m is defined by the following equation.

[0039] Vx _m = [h _m, z _m, ε _m] ^T · · (7) where, Vx _m mean 0, a covariance matrix,

[0040]

[Equation 7]

Is a Gaussian random vector with.
Furthermore, a two-dimensional column vector Vr _m having the estimated value hh _m of the propagation path as an element in the received signal r _m is defined by the following equation. Vr _m = [r _m, hh _m] ^T ·· (9) Vr _m can be expressed as follows using the Vx _m.

[0042]

[Equation 8]

From this, Vr _m is 0, the covariance matrix,

[0044]

[Equation 9]

Is a Gaussian random vector with. Thus, the conditional probability density function of Vr _m when Vs ⁽ⁱ⁾ is transmitted is given by the following equation.

[0046]

[Equation 10]

M = 1 ,. ． ． , N received signal vectors are assumed to be statistically independent. At this time,
{R _1, ·· r _N} when Vs ⁽ⁱ⁾ is sent conditional probability density function of can be written in the form of a product of conditional probability density function of Vr _m.

[0048]

[Equation 11]

Furthermore, the logarithm of this equation is obtained, the terms unrelated to the determination are omitted, and approximation is performed, whereby the decision variable is given by the same equation (14) as the equation (4).

[0050]

[Equation 12]

Further, by approximating and simplifying the above equation, the decision variable can be expressed as in equation (15), which is the same as equation (5).

[0052]

[Equation 13]

However, α and β are constants. Therefore, in each of the decision variable calculation units 31 to 3n, the above equation (14) or equation (15) is calculated using the complex amplitude fluctuation estimated by the complex amplitude fluctuation estimator 24 and the received coded modulation signal as input information. As a result, the decision variable corresponding to the code word of the coded modulated signal can be output.

Then, when the above equation (14) is calculated,
As shown in FIG. 6, the decision variable calculation units 31 to 3n include the matrix calculator 61, the complex conjugate calculators 51 and 52, the multiplier 53,
54, an adder 55, and an integrator 56.
Here, the matrix calculator 61 linearly transforms the complex amplitude fluctuation and the reception coded modulation signal estimated by the complex amplitude fluctuation estimator 24 using the covariance matrix of the reception coded modulation signal, and performs a complex conjugate calculation. The devices 51 and 52 calculate the complex amplitude fluctuation estimated by the complex amplitude fluctuation estimator 24 and the complex conjugate of the received coded modulation signal.

The multiplier 53 obtains product information of the complex amplitude fluctuation linearly converted by the matrix calculator 61 and the complex conjugate information of the complex amplitude fluctuation obtained by the complex conjugate trainer 51.
The multiplier 53 obtains product information of the reception coded modulation signal linearly converted by the matrix calculator 61 and the complex conjugate information of the reception coded modulation signal obtained by the complex conjugate calculator 51.

The adder 55 adds the two product information obtained by the multipliers 53 and 54, and the integrator 56 integrates the output from the adder 55 to determine the decision variable corresponding to the code word. Is output as. Therefore, in each of the decision variable calculation units 31 to 3n illustrated in FIG. 6, first, the estimated value of the fading complex amplitude fluctuation and the received signal are expressed by the matrix calculator 61 in a 2 × 2 matrix [(11) expression. Inverse matrix]. At the same time, the complex conjugate calculators 51, 5
By 2, the estimated value of the fading complex amplitude variation and the complex conjugate of the received signal are obtained. Further, the multipliers 53 and 54 determine the product of the linearly converted signal and the complex conjugate signal for each of the two sets of signals.
Then, the adder 55 further calculates the sum of the products. This sum signal is integrated by the integrator 56 over the code word of the coded modulation signal, and this becomes the decision variable shown in Expression (14).

When calculating the above equation (15), the decision variable calculators 31 to 3n are, as shown in FIG. 7, replica signal generator 71, multiplier 72, inter-signal distance calculator 7
3, a weight calculator 74, a multiplier 75, and an integrator 76. Here, the replica signal generator 71
Is a replica signal of the coded modulation signal sent from the transmitter 1, and the multiplier 72 has a replica signal generated by the replica signal generator 71 and a complex signal estimated by the complex amplitude fluctuation estimator 24. It is to be multiplied by the amplitude fluctuation.

The inter-signal distance calculator 73 calculates the inter-signal distance from the output from the multiplier 72 and the received coded modulated signal. The weight calculator 74 calculates weight information according to the magnitude of the estimation error of the complex amplitude fluctuation based on the replica signal generated by the replica signal generator 71.

The multiplier 75 multiplies the weight information from the weight calculator 74 by the output from the inter-signal distance calculator 73, and the integrator 76 integrates the output from the multiplier 75, It is output as a judgment variable corresponding to the code word. Therefore, in each of the decision variable calculation units 31 to 3n shown in FIG. 7, first, the estimated value of the fading complex amplitude fluctuation is multiplied by the replica signal of the transmission signal by the multiplier 72, and the inter-signal distance calculator together with the reception signal. It is input to 73 and the inter-signal distance between the two input signals is calculated. The replica signal of the transmission signal is also input to the weight calculator 74 at the same time,
The weighting factor 1 / (α + β | Vs _m ⁽ⁱ⁾ | ² ) is calculated. The weighting factor and the inter-signal distance are multiplied by a multiplier 75 and integrated by an integrator 76 over the code word of the coded modulated signal. Then, this integrator output becomes a decision variable based on the equation (15).

Next, in order to clarify the effect of the decoding method under fading of the coded modulation system according to the present invention, the literature [Okada, Hara, Morinaga: "In the error rate of the block coded modulation system under multipath fading, Kai ”, IEICE Technical Report, RCS92-94, pp. 59-64, (1
992-11)] is used to evaluate the bit error rate characteristics when transmission is performed under fading. The block coding modulation method used here is one in which the signal point arrangement of codewords is optimized by using a quasi-Newton method which is one of nonlinear programming methods. Here, block coded modulation of K = 4 bits and N = 4 symbols was used. The signal point arrangement of this code word is shown in FIG.

FIG. 9 shows the upper bound of the bit error rate when decoding is performed using the conventional decoding method and the decoding method according to the present invention. In FIG. 9, r = 0 represents the signal due to fading. The characteristic is shown when the amplitude fluctuation can be estimated without error. In this case, there is no difference between the decoding method according to the present invention and the conventional method. On the other hand, r = 1 is a characteristic when the variance of the estimation error is the same as that of the additive white Gaussian noise. In this case, it can be seen that by using the decoding method according to the present invention, it is improved by about 0.7 dB over the conventional method.

As described above, according to the present invention, it is possible to reduce the deterioration of the error rate characteristic due to the estimation error of the fading complex amplitude fluctuation, and to improve the quality of digital transmission in the fading channel. .

[0063]

As described above in detail, according to the decoding method and the decoding apparatus of the coded modulation signal of the present invention, it is possible to obtain the weighting processing according to the magnitude of the estimation error of the complex amplitude fluctuation due to fading. Code of the modulated coded signal
Since the coded modulation signal is decoded based on the decision variable corresponding to the word, it is possible to reduce the deterioration of the error rate characteristic due to the estimation error of the fading complex amplitude fluctuation, which enables digital transmission in the fading channel. There is an advantage that can improve the quality of.

Further, in the decoding apparatus of the present invention, the decision variable computing means uses the complex amplitude fluctuation estimated by the estimating means and the reception coded modulation signal as input information to obtain the equation (4) or the equation (1).
Since the decision variable corresponding to the codeword of the coded modulated signal is output by calculating 4), the decision variable can be obtained exactly, and
There is an advantage that it can greatly contribute to the reduction of the deterioration of the error rate characteristic due to the estimation error of the fading complex amplitude fluctuation.

Further, in the decoding device of the present invention, the decision variable computing means computes equation (5) or equation (15) using the complex amplitude fluctuation estimated by the estimating means and the received coded modulation signal as input information. By doing so, the decision variable corresponding to the codeword of the coded modulated signal is output, so that the decision variable can be easily obtained, and by this means, fading complex amplitude fluctuation of fading can be performed by a simple means. There is an advantage that the deterioration of the error rate characteristic due to the estimation error of can be reduced.

[Brief description of drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a block diagram showing a wireless communication system to which the present invention is applied.

FIG. 3 is a block diagram showing a transmitter in a wireless communication system to which the present invention is applied.

FIG. 4 is a block diagram showing a receiver in a wireless communication system to which the present invention is applied.

FIG. 5 is a block diagram showing a decoder in a receiver in a wireless communication system to which the present invention is applied.

FIG. 6 is a block diagram showing an example of a decision variable calculation unit in the decoder according to the embodiment of the present invention.

FIG. 7 is a block diagram showing another example of the decision variable calculation unit in the decoder according to the embodiment of the present invention.

FIG. 8 is a diagram showing a design example of a BCM.

FIG. 9 is a diagram showing an effect of the present invention in comparison with a conventional one.

[Explanation of symbols]

1 transmitter 2 receiver 11 Serial-parallel converter 12 Codebook 13,14 Digital / Analog converter 15 Orthogonal transformer 21 Quadrature detector 22,23 Analog / digital converter 24 Complex amplitude fluctuation estimator (estimating means) 25 Decoder (Decoding means) 31-3n Judgment variable calculation unit (judgment variable calculation means) 41 Comparison judgment device (selection means) 51,52 complex conjugate calculator (complex conjugate calculating means) 53, 54 Multiplier (multiplication means) 55 Adder (Adding means) 56 integrator (integrating means) 61 matrix calculator (matrix calculator) 71 Replica signal generator (replica signal generating means) 72 multiplier (first multiplication means) 73 Signal distance calculator (signal distance calculation means) 74 Weight calculator (weight calculation means) 75 multiplier (second multiplying means) 76 integrator (integrating means) 101 estimation means 102 decryption means 104 selection means 1031 to 103n Judgment variable calculation means

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Norihiko Morinaga 4-6-1-1012 Yamada Nishi, Suita City, Osaka Prefecture (56) References JP-A-5-37407 (JP, A) JP-A-4-20148 ( JP, A) Bit error rate characteristics of block coding and modulation schemes under multipath fading, IEICE Technical Report (RCS92-113), The Institute of Electronics, Information and Communication Engineers, January 20, 1993. Sun, Vol. 92, No. 411, PP. 85-90 IEICE Technical Report, RC S92-94 IEICE Technical Report, IT 92-47 IEICE National Conference, 93-Spring-Volume 2-B293 (58) Fields investigated (Int .Cl. ⁷ , DB name) H04L 25/08 H04L 1/00 H04L 27/00 H04Q 7/38

Claims (7)

(57) [Claims] 1. When a coded modulated signal transmitted from a transmitter via an environment where fading exists is received and decoded, a complex amplitude fluctuation due to the fading is estimated, and then the estimated complex amplitude is calculated. using variation and the reception coded modulation signal, and, said code modulation obtained by performing weighting processing corresponding to the magnitude of the estimation error with the complex-amplitude variation
A method for decoding a coded modulated signal, which comprises decoding the coded modulated signal based on a decision variable corresponding to each codeword of the signal. 2. A decoding apparatus for a coded modulation signal, which receives and decodes a coded modulation signal sent from a transmission apparatus via an environment where fading exists, and estimates a complex amplitude fluctuation due to the fading. estimated hand stage
When, using the received coded modulation signal with complex amplitude variation estimated by said estimation hand stage, and was obtained by performing the weighting process in accordance with the magnitude of the estimation error with the complex-amplitude variation
Based on the decision variable corresponding to each codeword of the code-modulated signal,
It can, characterized in that it is configured to include a decoding means to decode the encoded modulation signal, decoding device of the coded modulation signal. 3. A ring in which fading exists from a transmitter.
Receiving the coded modulation signal sent via the precinct
Estimating means for estimating a complex amplitude fluctuation due to the fading in a decoding device for a coded modulation signal to be decoded
And the complex amplitude fluctuation estimated by the estimating means and the reception coded modulation
And the estimation error of the complex amplitude fluctuation
By performing a weighting process according to the size, the code
Comprising a decoding means for decoding the coded modulation signal, the decoding hands stage inputs the estimated by the estimated hand stage was the complex amplitude fluctuation and receiving coded modulation signal, using these signals, and, the complex- by performing weighting processing corresponding to the magnitude of the estimation error with the amplitude variation, a plurality of determination variable processing means to calculating the decision variable corresponding to each codeword of the encoded modulation signal, each decision variable calculation hand by comparing the decision variable obtained at stage, characterized in that the minimum decision variables is configured to include the selection means to select as the decoding information about the encoded modulation signal
Decoding device sign-coded modulation signal. Wherein said determination variable calculation hand stage, as input information and estimated <br/> constant is the complex amplitude fluctuation and the received coded modulation signal with the estimated hand stage, Equation 1] 4. The decoding device for the coded modulation signal according to claim 3, wherein a decision variable corresponding to the codeword of the coded modulation signal is output by calculating. Wherein said determination variable calculation hand stage, a matrix operation means for linearly converted using a covariance matrix of the estimated by the estimated hand stage the complex amplitude fluctuation and receiving coded modulation signal received coded modulation signal , a complex conjugate calculating means for calculating a complex conjugate of the estimated hand stage in the estimated complex amplitude variation and receiving coded modulation signal, and the complex amplitude variation which is linearly converted in this matrix calculation means, with the complex-conjugate computing unit The product information of the obtained complex amplitude variation and the complex conjugate information is obtained, and the received coded modulated signal linearly converted by the matrix computing means and the complex of the received coded modulated signal obtained by the complex conjugate computing means are obtained. Multiplication means for obtaining product information with the conjugate information, addition means for adding two product information obtained by the multiplication means, output from the addition means is integrated, and output as a decision variable corresponding to the codeword. And the integration means Decoder of coded modulation signal according to claim 4, characterized in that it is configured. Wherein said determination variable calculation hand stage, as input information and estimated <br/> constant is the complex amplitude fluctuation and the received coded modulation signal with the estimated hand stage, Equation 2] 4. The decoding device for the coded modulation signal according to claim 3, wherein a decision variable corresponding to the codeword of the coded modulation signal is output by calculating. 7. The decision variable calculation hand stage, the replica signal generation means for generating a replica signal of the coded modulation signal sent from the transmitting apparatus, and the replica signal generated by the replica signal generation means,
First multiplying the complex amplitude fluctuations estimated by the estimated hand stage
Multiplying means, inter-signal distance calculating means for calculating an inter-signal distance from the output from the first multiplying means and the received coded modulated signal, and the complex signal based on the replica signal generated by the replica signal generating means. Weight calculation means for calculating weight information according to the magnitude of the estimation error of the amplitude fluctuation, and second multiplication means for multiplying the weight information from the weight calculation means and the output from the inter-signal distance calculation means. 7. A decoding device for a coded modulated signal according to claim 6, further comprising: an integrating means for integrating the output from the second multiplying means and outputting it as a decision variable corresponding to the code word. .