TW201442437A - Step-by-step decoding algorithm for Reed Solomon codes combining with quadrature amplitude modulation - Google Patents

Abstract

The invention relates to a step-by-step decoding algorithm for Reed Solomon codes combining with quadrature amplitude modulation. Especially for a decoding algorithm in which the Reed Solomon codes is utilized to combine the modified step-by-step decoding algorithm with the quadrature amplitude modulation. Primarily, the Reed Solomon codes consist of m-bits are utilized to correspond to the QAM constellations of m-bits to break the limitation that traditional step-by-step decoding algorithm is not applied for decoding Reed Solomon codes. It can achieve the purposes of saving the action of arranging messages efficiently, reserving the characteristic that burst errors can be decoded by the Reed Solomon codes and reducing the complexity of the decoding operation and the consumption of time and space. Thus it can not only improve the decoding capability for the low noise but also achieve the purpose of enhancing the quality of information transmission of wireless communication efficiently.

Description

RS code step decoding method combined with QAM modulation

The invention relates to a RS code step decoding method combining QAM modulation, in particular to a modified step-by-step using Reed Solomon Codes (RS code) combined with improved step decoding. Decoding algorithm and decoding method of Quadrature Amplitude Modulation (QAM modulation) system, mainly consisting of m-bits symbol corresponding to m-bits QAM modulation constellation (constellation) In order to break through the traditional step decoding method, it is not applicable to the limitation of Reed Solomon code decoding, which can effectively solve the operation of decoding the message arrangement and the calculation of the reduced decoding, and also retain the Reed Solomon code to solve the burst error. Characteristics, effectively reducing the complexity of the decoding operation and the time spent Space, not only can improve further in order to decode low noise decoding capabilities, more effectively achieve the purpose of enhancing the quality of information transmission of radio communications.

With the rapid development of science and technology, the communication and transmission of information by many technologies, such as wireless communication and satellite communication applied to the Internet, has been closely related to human life. These technologies are not only provided by the vigorous development of communication systems. Higher speed performance must also create a stable and reliable environment for data transmission and preservation to prevent confidential and sensitive (smart) data from being lost due to various adverse conditions, thereby maintaining good transmission quality and allowing users to use it. No worries.

In the process of transmission, the signal is often disturbed by external noise, and the channel noise, weakening or interference between the transmitting end and the receiving end will also distort the signal passing through the channel, and the degree of noise interference varies. , the signal received by the receiving end will also be different from the original transmitted signal, especially in the future when wireless video and high-definition digital TV are more popular, more important information will be transmitted, therefore, when After the data sent by the signal source is converted into a digital signal, when the data is to be transmitted, the user will add some new symbols after the data or convert it into a longer message to obtain the code. Coding Gain, in order to clearly determine the correctness of receiving this signal when receiving the data at the receiving end. Therefore, in order to overcome the distortion of part of the signal caused by the interference of channel noise during transmission, it is often necessary to artificially increase some Structural Redundancy information that enables this channel system to automatically detect errors and corrections Misuse of power.

In order to achieve the purpose of distortion signal correction and correction, many fault-tolerant technologies have been developed. These fault-tolerant technologies mainly operate by means of hardware or software, so that the sensitive files can be transferred or saved in a reliable and correct way. The purpose is to use the Error Correction Code, which is the most important in all kinds of developed fault-tolerant technologies, in response to various situations that may make the sensitive file threatened. The error correction code can effectively make errors in transmitting data. Detection and correction functions, and different error correction codes are often designed to adapt to a variety of different environments to cope with the threat of information loss in various environments.

In addition, the step decoding method is a decoding method with faster decoding speed. The decoding process of the algorithm first calculates the error symptom (syndrome), and then checks the code words of the received signals one by one to determine each bit. Whether the element is wrong or not, the method of checking is to invert each signal bit first, that is, to invert logic 0 into logic 1 or invert logic 1 into logic 0 to observe the change of the number of errors, the error The increase in number means that the information of the bit is correct. The bit must be restored. Otherwise, the wrong bit is found and the bit can be corrected directly. However, the traditional step decoding method is commonly used. The two-bit decoding method, with the rapid increase of wireless transmission of information and the continuous occurrence of group error, the binary codec method is completely inadequate, so the current codec technology has used non-two bits. The meta-method replaces the two-bit, and the most famous non-two-bit codec is the Reed Solomon code.

In the field of wireless communication, especially after entering the global technology flow of personal mobile communication, the huge multimedia communication volume and the global seamless coverage demand have established the mainstream status of the wireless broadband communication system (Broadband Communication System), the wireless broadband The communication system includes mobile personal cellular communication (Personal Cellar Communication), high-speed wireless local network (Wireless Local Network) and global satellite communication (Satellite Communication) system, mainly through vertical and horizontal integration and The use of different communication systems to complete mobile, high-global transmission and high-quality wireless communication services, which is why there will be more multimedia traffic to be transmitted and saved in the future, in order to avoid The transmitted signal is distorted by the transmission, although It is solved by amplifying its power, but it is actually wasting more energy. If it is avoided by using a codec with large decoding capability, it will be accompanied by more complicated calculations and consume more energy. And time, in addition, the traditional step decoding method has the disadvantage of repeated iteration operations, especially when dealing with longer code lengths, it highlights the complexity and difficulty of the traditional step decoding method. Therefore, how to choose A fast and accurate way to correct the error message transmitted, while also reducing the complexity of the system and the amount of computation and time of decoding, is still a problem that the relevant industry needs to continuously overcome and solve.

Nowadays, the inventor is in view of the fact that the above-mentioned existing smart file encoding and decoding mechanism is too long and complicated to be used in the process of Reed Solomon code decoding due to the traditional step decoding method, so it is a tireless spirit and borrows It is improved by its rich professional knowledge and years of practical experience, and the present invention has been developed based on this.

The main object of the present invention is to provide a decoding method using a Reed Solomon code combined with an improved step decoding and QAM modulation system, which can effectively reduce the amount of computation and time and space of decoding, in order to achieve information that can enhance wireless communication. For the purpose of transmission quality, the decoding mode is based on Reed Solomon code and modulation characteristics. A Reed Solomon code with Galois Field 2 ^m as the finite field must be combined with 2 ^m -QAM. Correspondence, an m-bits can be used to represent a polynomial coefficient of a Reed Solomon code, and an m-bits can also be used to represent a constellation point of the QAM modulation. Therefore, each of the Reed Solomons can be utilized with this feature. The symbol of the code corresponds to the constellation point on the 2 ^m -QAM constellation. Therefore, if the demodulated QAM constellation point coincides with the transmitted QAM constellation point, then the Reed Solomon code of this transmission does not have any error, and vice versa. , QAM constellation points if the demodulation is ² m -1 falling stars Point, an error message is displayed is present in the signal transmission, the decoding order of steps when a conventional method to solve Reed Solomon code, a symbol must turn (2 m ^-1) times, when there are n symbols hypothesis, conventional The step decoding method must be used to rewrite (2 ^m -1) n times in Reed Solomon code decoding, but the improved step decoding method combines QAM modulation technology to make one symbol only need to be turned over once. That is, there are several symbols that are turned over several times. This method can effectively solve the operation of message arrangement and the computational complexity of decoding, and also retains the characteristics of Reed Solomon code to solve group errors, not only breaking the step decoding method. Rarely used in the Reed Solomon code decoding limitations, can also effectively reduce the complexity of the operation and improve the decoding ability of low noise.

In order to achieve the above-mentioned implementation purposes, the inventors have developed the following implementation techniques. First, a coded signal with a Reed Solomon code step code and QAM modulation is received; then, an m-bits symbol of the Reed Solomon code is utilized. Corresponding to the constellation point of the m-bits of the QAM modulation system, one constellation point corresponding to the symbol of a Reed Solomon code; and then determining the constellation point closest to the coded signal, defined as the first proximity constellation point (First Near Constellation Point, FNCP), and taking the first close constellation point as a new origin; then, calculating the symptom value of the encoded signal by using the first close constellation point, and calculating the error using the syndrome matrix Number, if no error occurs, the result is decoded again by the small capability decoder to solve the error of higher noise; then, the coordinates of the four-point constellation adjacent to the first close constellation point and the absolute value of the coded signal are calculated. Distance, the definition is closest to the The constellation point of the code signal is a Second Near Constellation Point (SNCP), recalculating the symptom value of the second close constellation point, and using the syndrome matrix to determine the number of errors; and then comparing the second proximity a constellation value of the constellation point and the first proximity constellation point, and a decrease in the symptom value of the second proximity constellation point represents a symbol that has corrected the error; after that, each symbol is checked one by one to confirm that the number of errors is reduced to verify The correct coordinate value of the coded signal, and finally, the decoded result is decoded again by the small capability decoder to solve the situation of higher noise.

In an embodiment of the invention, the encoding end is combined with a QAM modulator by a step encoding algorithm, and the QAM modulation system at the decoding end is designed with a low complexity algorithm system.

In an embodiment of the invention, the coded signal encoded and decoded by Reed Solomon code is implemented by Matlab software.

(1). . . Coded message

(2). . . QAM modulation system

(3). . . First close to the constellation point

(4). . . Symptom value

(5). . . Number of errors

(6). . . Small capability decoder

(7). . . Second close to the constellation point

(S1). . . step one

(S2). . . Step two

(S3). . . Step three

(S4). . . Step four

(S5). . . Step five

(S6). . . Step six

(S7). . . Step seven

(S8). . . Step eight

First: Flow chart of steps of the RS code step decoding method combined with QAM modulation according to the present invention

The second figure: a schematic diagram of the relationship configuration of the RS code step decoding method combined with QAM modulation according to the present invention

The object of the present invention and its structural design and advantages will be explained in the light of the preferred embodiments shown in the following drawings, so that the reviewing committee can have a more in-depth and specific understanding of the present invention.

First, please refer to the first to second embodiments, which are schematic flowcharts of the steps and relationship configuration of the decoding method according to the preferred embodiment of the present invention. The steps include:

Step 1 (S1): receiving a coded signal with a Reed Solomon code step code and QAM modulation (1);

Step 2 (S2): using the m-bits symbol of the Reed Solomon code to correspond to the constellation point of the m-bits of the QAM modulation system (2), one constellation point corresponding to the symbol of a Reed Solomon code;

Step 3 (S3): determining a constellation point closest to the coded signal (1), defined as a first proximity constellation point (3), and using the first proximity constellation point (3) as a new origin;

Step 4 (S4): calculating the symptom value (4) of the coded signal (1) by the first close constellation point (3), and calculating the number of errors (5) by using the syndrome matrix, if no error occurs, to small The capability decoder (6) decodes the result once again to resolve the higher noise error;

Step 5 (S5): calculating the absolute distance between the coordinates of the four-point constellation point adjacent to the first close constellation point (3) and the coded signal (1), and defining the constellation point closest to the coded signal (1) as the second Close to the constellation point (7), recalculate the symptom value (4) of the second close constellation point (7), and use the syndrome matrix to determine the number of errors (5);

Step 6 (S6): comparing the symptom value (4) of the second proximity constellation point (7) with the first proximity constellation point (3), and the symptom value of the second proximity constellation point (7) (4) Reduce the symbol representing the error that has been corrected;

Step 7 (S7): Check each symbol one by one to confirm the number of errors (5) to verify the correct coordinate value of the coded signal (1);

Step 8 (S8): The decoded result is decoded again by the small capability decoder (6) to solve the situation of higher noise.

In addition, the encoding end is combined with the QAM modulator by the step encoding algorithm, and the QAM modulation system (2) located at the decoding end is designed with a low complexity algorithm system. Furthermore, the Reed Solomon code is used for encoding and decoding. The coded signal (1) is completed by Matlab software.

The RS code step decoding method and the implementation description combined with the QAM modulation described above show that the present invention has the following advantages:

1. The RS code step decoding method of the present invention combined with QAM modulation is combined with the codec technology of the Reed Solomon code and the improved step decoding method and the QAM modulation system, and the symbols composed of m-bits are corresponding to The m-bits QAM modulation system constellation point saves the operation of the message arrangement and the amount of decoding operation, and also retains the Reed Solomon code's ability to solve the group error. The traditional step decoding method is not applicable to the Reed Solomon code. The limitation of decoding effectively reduces the complexity of decoding operations.

2. The invention combines QAM modulation RS code step decoding method by improving the traditional step decoding method, and is used as a decoding method of Reed Solomon code, which not only solves the step decoding technique for Reed Solomon code. The complexity of decoding, combined with QAM modulation, makes its decoding ability have good effects under low noise.

3. The RS code step decoding method combined with QAM modulation can greatly reduce the computation and consumption time and space of decoding, and can be widely applied to digital television or satellite communication and multimedia signals encoded by Reed Solomon code. Transfer and save.

In summary, the RS code step decoding method combined with the QAM modulation of the present invention can achieve the expected use efficiency by the above disclosed embodiments, and the present invention has not been disclosed before the application. Full compliance with the requirements and requirements of the Patent Law.爰Issuing an application for a patent for invention in accordance with the law, and asking for a review, and granting a patent, is truly sensible.

The illustrations and descriptions of the present invention are merely preferred embodiments of the present invention, and are not intended to limit the scope of the present invention; those skilled in the art, which are characterized by the scope of the present invention, Equivalent variations or modifications are considered to be within the scope of the design of the invention.

(S1). . . step one

(S2). . . Step two

(S3). . . Step three

(S4). . . Step four

(S5). . . Step five

(S6). . . Step six

(S7). . . Step seven

(S8). . . Step eight

Claims (3)

A RS code step decoding method combining QAM modulation, the steps of which include:
Step 1: receiving a coded signal of Reed Solomon Codes (RS code) step coding and Quadrature Amplitude Modulation (QAM);
Step 2: Using the m-bits symbol of the Reed Solomon code to correspond to the constellation of the m-bits of the QAM modulation system, one constellation point corresponding to the symbol of a Reed Solomon code;
Step 3: determining a constellation point closest to the coded signal, defined as a first proximity constellation point, and using the first proximity constellation point as a new origin;
Step 4: Calculate the syndrome value of the coded signal by using the first close constellation point, and calculate the number of errors by using a syndrome matrix. If no error occurs, the result is decoded again by the small capability decoder. To solve the error of higher noise;
Step 5: Calculate the absolute distance between the coordinate of the four-point constellation point adjacent to the first close constellation point and the coded signal, define a constellation point closest to the coded signal as a second close constellation point, and recalculate the second close constellation point. The symptom value, and use the syndrome matrix to determine the number of errors;
Step 6: Comparing the symptom value of the second proximity constellation point and the first proximity constellation point, and the reduction of the symptom value of the second proximity constellation point represents a symbol that has corrected the error;
Step 7: Check each symbol one by one to confirm that the number of errors is reduced to verify the correct coordinate value of the encoded signal;
Step 8: The decoding result is solved again by the small capability decoder to solve the error of higher noise. The RS code step decoding method combined with QAM modulation according to claim 1, wherein the encoding end is combined with a QAM modulator by a step encoding algorithm, and the QAM modulation system at the decoding end is Low complexity algorithm system design. The RS code step decoding method combined with the QAM modulation described in claim 1 is wherein the codec is simulated by Matlab software.