Code modulation method and system

Abstract

The invention provides a code modulation method and system adopting a Raptor-like Irregular QC-LDPC code. The code modulation method includes the steps that the code modulation system receives input information bits; LDPC channel coding is conducted on the information bits according to a check matrix of the Raptor-like Irregular QC-LDPC code to generate coding bits; bit mapping is conducted on the coding bits to obtain mapping bits; constellation mapping is conducted on the mapping bits to obtain constellation mapping symbols, and the constellation mapping symbols pass through an equivalent transmission channel to obtain receiving symbols; bit soft de-interleaving is conducted on extrinsic information of the mapping bits to generate prior information of the coding bits; the prior information of the coding bits is decoded to obtain the extrinsic information of the coding bits; bit soft interleaving is conducted on the extrinsic information of the coding bits to generate the prior information of the mapping bits, and LDPC decoding results are output after multiple iterations. The code modulation method improves the flexibility of a communication system, simplifies a realization method of a channel decoder applied to a variety of services and facilitates improvement of the handling capacity and the expansibility of a code modulation system.

Description

Technical field [0001] The present invention relates to the technical field of digital information transmission, in particular to a coding modulation method and system. Background technique [0002] In the field of communication, channel coding technology is usually used to ensure the effectiveness and reliability of communication in noise and interference channels. For example, in a satellite communication system, due to the influence of geographical and environmental factors, there are a large number of noise sources. These communication channels have their theoretical maximum communication capacity (that is, the Shannon limit of information theory), which can be represented by the bit rate (bps) of a given channel under a specific signal-to-noise ratio (SNR) condition. One of the error control codes close to the Shannon limit is the low-density parity-check code (LDPC). At present, LDPC codes have been widely used due to their error correction performance approaching the Sha...

AI Technical Summary

Problems solved by technology

[0013] 3. The information bit length of this scheme is constant, which is 4800 bits. Changing the length of the information bit requires redesigning the interleaver, which cannot meet the needs of various services and increases the complexity

[0014] 4. This scheme is limited by the decoding algorithm of the convolutional code as a component code, and there is still room for improvement in its maximum throughput and scalability

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