KR20020017276A - Decoding apparatus for wire/wireless communication system - Google Patents

Abstract

PURPOSE: A decoding apparatus of a wire/wireless communication system is provided to operate correlatively a signal demodulator and an SCE decoder and perform an adaptive demodulating function by applying a feedback concept. CONSTITUTION: A BIBO module(410) performs a particular calculation process for modulated signals or a calculation process for a feedback signal received from an SCE decoder(430) until a particular condition is satisfied. A deinterleaver(420) is used for recovering an output signal of the BIBO module(410) to an original state. The SCE decoder(430) performs a decoding process for output signals of the deinterleaver(420), converts unused information of the decoded values to information of a predetermined type, and performs a feedback process for the converted information to the BIBO module(410) until a particular condition is satisfied. An interleaver(440) is used for interleaving a feedback value of the SCE decoder(430) to the BIBO module(410).

Description

DECODING APPARATUS FOR WIRE / WIRELESS COMMUNICATION SYSTEM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for efficiently performing a decoding function in a next generation mobile communication system. In particular, the present invention provides an improved demodulation function regardless of a modulation scheme when demodulating a signal transmitted after being modulated through a serial link encoder, an interleaver, and a mapper. The present invention relates to a decoding apparatus of a wired and wireless communication system.

In the next generation mobile communication system, a strong error correction code is used to satisfy various transmission speeds and quality of service. Representative examples of serial concatenated codes corresponding thereto include a serially concatenated block code (SCBC) and a serially concatenated convolutional code (SCCC).

In particular, next-generation mobile communication systems use a signal mapper in addition to simple BPSK or QPSK for high-speed data transmission (eg 8-PSK, 16-QAM, 32-QAM, etc.) with high signal constellation. There is a trend to introduce.

1 is a block diagram illustrating a modulation stage of a general wired / wireless communication system, and a serial concatenated encoder 110 encoding an input signal sequence using a strong error correction code to satisfy various transmission speeds and quality of service; A puncturing unit 120 for outputting a portion of the output data of the serial chain encoder 110 in a repeated form; An interleaver (130) for interleaving or scrambling the output data of the puncturing unit (120); According to the mapper selection signal (MSS) is composed of a mapper 140 to group the bits input from the interleaver 130 in a predetermined number unit to convert a specific transmission symbol and then transmit to the channel 150 side, the operation of the mapper 140 A description with reference to 2 as follows.

The serial concatenated encoder 110 may include two or more encoders, but it will be described here with an example consisting of two encoders 111A and 111B.

After the signal sequence input to the serial concatenation encoder 110 is encoded through the first encoder 111A, an interleaver (" The order of signals is changed to be more random through 112. The output data of the interleaver 112 is converted into a form in which a part of the interleaver 112 is removed or repeated by the puncturing unit 113, and then the second data is output again. The encoding process is performed through the encoder 111B. In the encoders 111A and 111B, R1 and R2 represent their code rates.

The serial data encoded by the serial chain encoder 110 through the above process is output in a form in which a part is removed or repeated by the puncturing unit 120, and the output data of the puncturing unit 120 is interleaver ( " The interleaver 130 is not limited to a conventional interleaver, but refers to a device that performs a scrambler or similar role. will be.

The mapper 140 generates Z signal bits inputted from the interleaver 130 according to the mapper selection signal MSS. ) Specific symbols It converts to. here, Is a mapper function. For example, when the mapper selection signal MSS corresponds to 16-QAM, a given input signal According to the output symbol Generates. A more detailed working principle of this mapper 150 is shown in FIG.

FIG. 2A illustrates an operation of the mapper 140 illustrated in FIG. 1, which corresponds to a case in which the mapper selection signal MSS corresponds to 16-QAM. In this case, the mapper 140 outputs 4 bits of the outputs of the interleaver 130. One output symbol, grouped together To match. Here, the subscript t is an index representing time. remind Is one of the elements of the set Χ, which is a mapper function Determined by Equivalent to 16-QAM Is defined in Fig. 2B, and the set? Is defined by the following equation.

here, These constellations are shown in the right figure of FIG. 2B.

3 is a block diagram of a conventional demodulation stage corresponding to the modulation stage shown in FIG. 1.

The symbol signal transmitted through the channel 150 after being modulated through the modulation stage as shown in FIG. ) Is demodulated by the demodulator 310, and the deinterleaver 320 performs the reverse function of the interleaver, and is then input to the SCE decoder 330.

In this case, the SCE decoder 340 performs a decoding process by the SISO module 331 for the second encoder and the SISO module 333 for the first encoder, the deinterleaver 332A, and the interleaver 332B. Reference numeral 333 denotes an SISO module operated by a SISO decoding algorithm.

The reception signal determination unit 340 determines what signal is a received signal decoded by the SCE decoder 330.

However, in such a conventional decoding device, since the signal demodulator and the SCE decoder operate independently, it is difficult to adaptively adapt to various modulation schemes at the modulation stage, and excellent decoding performance can be exhibited. There was no fault.

Accordingly, an object of the present invention is to provide an adaptive demodulation function corresponding to various modulation schemes in a modulation stage, and to apply a reverse feedback concept to a signal demodulator and an SCE decoder to operate in correlation with each other. In providing a decoding device.

1 is a block diagram of a modulation stage of a wired and wireless communication system according to the prior art.

FIG. 2A is an explanatory diagram of the operation of the mapper when the 16-QAM modulation scheme is selected in FIG. 1; FIG.

FIG. 2B is a function when the 16-QAM modulation scheme is selected in FIG. Diagram of operation of the.

3 is a block diagram of a demodulation stage according to the prior art;

Figure 4 is an exemplary block diagram of a demodulation stage according to the present invention.

5 is a detailed block diagram of the SCE decoder in FIG.

6 is a diagram illustrating one output relationship of a trellis encoder to which the present invention is applied.

7 is an explanatory diagram of input / output relationships of a SISO module to which the present invention is applied;

FIG. 8 is an explanatory diagram of input and output relationships of a BIBO module in FIG. 5; FIG.

9A and 9B are explanatory diagrams of input and output relationships of the bit / symmetric metric converter in FIG.

10A and 10B are explanatory diagrams of input and output relationships of a symbol / bit metric converter in FIG. 5;

*** Description of the symbols for the main parts of the drawings ***

410: BIBO module 420: deinterleaver

430: SCE decoder 440: interleaver

450: reception signal determination unit

According to a first aspect of the present invention, the output of the SCE at the modulation stage is passed through an interleaver, a scrambler, or a device having a similar function, and then various modulation schemes (eg, 8-PSK, 16-QAM, 32-) through a mapper. In a demodulation stage of a wired / wireless communication system that transmits signals using QAM, etc., a decoder performs a decoding function efficiently in response to various modulation schemes with one decoder structure.

According to a second aspect of the present invention, when a demodulation stage demodulates a signal transmitted through the modulation stage described in the first aspect, the received signal completes a specific calculation process through a specific module (for example, a BIBO module). In addition, the output information is provided as an input of the SCE decoder to perform one decoding process. Thereafter, among the output values of the SCE decoder, it is fed back to an appropriate form not used in the existing system and provided as an input of the BIBO module. Thereafter, the above process is repeated once. Thereafter, the above process is repeated until a given specific requirement is satisfied.

According to a third aspect of the present invention, the SCE decoder in the second aspect uses a SISO-based decoding algorithm.

According to the fourth aspect of the present invention, the hard decision value or the soft decision value may be used as information for reverse feedback among the output values of the SCE decoder in the second feature.

FIG. 4 is a block diagram showing an embodiment of a decoding apparatus of a wired / wireless communication system according to the present invention. As shown in FIG. A BIBO module 410 which performs a specific calculation process for the C-based signal and repeatedly performs a calculation process until a specific requirement is satisfied by receiving a signal returned from the SCE decoder 430 which will be described later; A deinterleaver 420 for restoring the signal output from the BIBO module 410 in an original order; A specific requirement given for performing a decoding process on a signal input from the deinterleaver 420 and converting predetermined information not used in an existing system among the output values into an appropriate form to reverse feedback to the BIBO module 410 side. An SCE decoder 430 which repeatedly performs until this is satisfied; An interleaver (440) for interleaving a value fed back from the SCE decoder (430) to the BIBO module (410); The reception signal determination unit 450 determines which signal is a received signal decoded by the SCE decoder 430. The operation of the present invention configured as described above is described in detail with reference to FIGS. 5 to 10. The explanation is as follows.

The BIBO (BIBO: Bit-Input Bit-Output) module 410 is a symbol signal transmitted through the channel 150 after being modulated through a modulation stage as shown in FIG. ) Is input to perform a certain operation.

The output signal of the BIBO module 410 is input to the SCE decoder 430 through the deinterleaver 420. The SCE decoder 430 performs a predetermined decoding process once using the input information. Some of the output is returned to be used as input to the BIBO module 410.

Thereafter, the operation of the BIBO module 410 is performed again, and then the operation of the SCE decoder 430 is performed once.

The above process is repeatedly performed until the given condition is satisfied.

The SCE decoder 430 uses a soft-input soft-output (SISO) -based algorithm to generate reverse feedback information. The input / output relationship of the SISO module is shown in FIGS. 6 and 7.

6 shows an arbitrary trellis coder 601 that generates codewords using trellis, which is input. Codeword Generates.

FIG. 7 illustrates an input / output value of the SISO module 701 when the decoding process is performed by applying the SISO module 701 to the trellis encoder 601 of FIG. 6. here, , , , Input of trellis encoder 601 And output codewords Are the probability values of. In the probability indication value " "Wow " Denotes probability values before and after passing the SISO module 701, respectively, which are calculated by a predetermined SISO decoding algorithm.

In addition, the operation principle of the BIBO module 410 is as follows. The input / output relationship of the BIBO module 410 is shown in FIG. 8. That is, the input signal of the BIBO module 410 is Wow And the output signal is to be. here, Is the received symbol, Wow Is input and output for each BIBO module 410 Is the probability value of.

At this time, All have a uniform distribution Give the same value for. Then, in the next iteration, the value returned from the SCE decoder 430 is used. A hard-decision value or a soft-decision value may be used as the value fed back to the BIBO module 410.

remind Is defined by the equation

remind Is a transmission symbol Indicates the degree of distortion of the signal generated by the channel through which Means that the complex addition is a white Gaussian noise. And, Wow Can be expressed by two equations.

First, when using soft decision values,

Where Is Generating J bit of Means the value of. here, , , to be. Meanwhile, Is defined as

Second, when using hard decision values,

In the above formula, Is determined by the following equation.

In the above formula, Are values determined by performing the previous one decoding iteration.

On the other hand, the operation of the SCE decoder 430 will be described in more detail with reference to FIG.

The bit / symbol metric converter 430A converts the probability of each bit input from the deinterleaver 420 into a symbol probability and provides it to the first input of the SISO module 430B for the second encoder.

The second encoder SISO module 430B is a value input from the bit / symbol metric converter 430A and the bit / symbol metric converter 430J, respectively. , Decryption process for and output value accordingly , Occurs.

First output value of the second encoder SISO module (430B) The signal is supplied to the interleaver 440 by the symbol-to-bit metric converter 430C, and then the probability values for the given symbols are converted into the probability values of the respective bits, and are output from the interleaver 440. Is provided as a first input of the BIBO module 410.

Also, a second output value of the second encoder SISO module 430B. Is provided as a first input of the first encoder SISO module 430G through a symbol / bit metric converter 430D, a deinterleaver 430E, and a bit / symmetric metric converter 430F.

The SISO module 430G for the first encoder is a value input from the bit / symbol metric converter 430F. And arbitrary values from outside Decode process for and output value accordingly , Occurs.

First output value of the first encoder SISO module (430G) Is provided to an input of the bit / symmetric metric converter 430J through a symbol / bit metric converter 430H and an interleaver 440I, and a second output value. The signal is provided to the reception signal determination unit 450 to determine which signal is a received signal that is currently decoded.

remind , , , , , Heard encoder input And encoder output codewords Are the probability values of. The subscripts "1" and "2" in these probabilities mean probabilities relating to the first encoder 111A and the second encoder 111B of FIG. And, " "Wow " "Means probability values before and after the passing of the SISO modules 430B and 430G.

9A and 9B exemplarily illustrate input / output relations of the bit / symbol metric converter 430A applied to FIG. 5, which converts and outputs a probability for each bit given as an input into a symbol probability. To perform. For example, if the code rate is In this case, the bit / symbol metric converter 430A converts the bit probabilities given as input into symbol probabilities using the following equation.

here, Silver symbol Is the value of the j th bit of Silver symbol Is the value of the j th bit in.

10A and 10B exemplarily illustrate the input / output relationship of the symbol / bit metric converter 430C applied to FIG. 5, which converts and outputs the probability of symbols given as input into the probability of each bit. Do this. For example, if the code rate is In this case, the symbol / bit metric converter 430C converts the symbol probabilities given as inputs into the probabilities of the respective bits using the following equation.

here, , Is a normalization constant, which is defined by the equation

As described in detail above, the present invention provides an adaptive demodulation function corresponding to various modulation schemes in a modulation stage, and applies a reverse feedback concept so that the signal demodulator and the SCE decoder operate in correlation with each other. As a result, the reliability and performance of the demodulation stage can be improved.

In addition, even if one modulation stage selects a modulation scheme in various forms using a signal mapper according to the situation, the demodulation stage can adaptively cope with it without changing the structure, thereby reducing the cost.

Claims (11)

A BIBO module which performs a specific calculation process on signals transmitted in various modulation forms and repeatedly receives a signal returned from the SCE decoder until a specific requirement is satisfied; SCE decoding means for performing a decoding process on the signal input from the BIBO module side, and then converts specific information from the output value into an appropriate form and performs the reverse feedback to the BIBO module side until the given specific requirement is satisfied. And a decoding device for a wired and wireless communication system. After performing a specific calculation process on the symbol signal transmitted in various modulation forms, the BIBO module 410 that receives the back-feedback signal from the SCE decoder 430 and performs the calculation process repeatedly until a specific requirement is satisfied; ; A deinterleaver 420 for restoring the signal output from the BIBO module 410 in an original order; After the decoding process is performed on the signal input from the deinterleaver 430, a predetermined information which is not used in the existing system among the output values is converted into an appropriate form, and is then fed back to the BIBO module 410 through the interleaver 440. And a SCE decoder (430) which repeats the process until the specified requirements are satisfied. The method of claim 2, wherein the input signal of the BIBO module 410 is Wow And the output signal is Is that Is the received symbol, Wow Is input and output Decoding device of a wired or wireless communication system, characterized in that the probability value of. The method of claim 3, wherein Is a decoding apparatus of a wired or wireless communication system, characterized in that the following formula. here, : Transmission symbol Value of the distortion of the signal caused by the pass channel : Means that complex part is white Gaussian noise The method of claim 3, Is the first operation The decoder of the wired / wireless communication system, wherein the decoded value is given to the same value, and the reverse feedback value is used at the next iteration. The apparatus of claim 2, wherein the value fed back to the BIBO module (410) is a hard decision value or a soft decision value. The apparatus of claim 2, wherein the SCE decoder (430) uses a SISO-based decoding algorithm. 3. The SCE decoder (430) of claim 2, further comprising: a bit / symmetric metric converter (430A) for converting a probability for each bit of the output data string of the deinterleaver (420) into a symbol probability; Values input from the bit / symbol metric converter 430A and the bit / symbol metric converter 430J , Decryption process for and output value accordingly , A second encoder SISO module 430B for generating a; First output value of the SISO module 440B for the second encoder A symbol / bit metric converter 430C which receives a and converts a probability value for a given symbol into a probability value of each bit and supplies it to the interleaver 440; Value input from the second encoder SISO module 430B side And arbitrary values from outside Decryption process for and output value accordingly , A first encoder SISO module (430G) for generating a; First output value of the second encoder SISO module (430G) Wired / wireless, comprising: a symbol / bit metric converter 430H, an interleaver 440I, and a bit / symmetric metric converter 430J for providing a second input of the SISO module 430B for the second encoder Decoding device for communication system. The method of claim 8, , , , , , Heard encoder input And encoder output codewords Decoding device of a wired or wireless communication system, characterized in that the probability value of. 10. The apparatus of claim 8, wherein the bit / symbol metric converter (430A) converts bit probabilities given as input into symbol probabilities using the following equation. here, Silver Symbol, The value of the j th bit in Silver symbol The value of the j th bit in The method of claim 8, wherein a symbol / bit metric converter 430D for converting the symbol probabilities given as inputs into the probabilities of the respective bits using the following equation is connected to the output terminal of the SISO module 430B for the second encoder. A decoding apparatus of a wired and wireless communication system, characterized in that. here, , Is a normalization constant