Application of LDPC Based on CRC and LLR-BP in SC-FDE System

• 1、School of Artificial Intelligence,Beijing University of Posts and Telecommunications,Beijing 100876

Abstract：Based on Shannon\'s theorem, channel coding technology has become one of the research focuses in the field of communication. How to construct close to the channel capacity of the encoding method and design a corresponding encoding method and decoding method to guarantee information transmission reliable has become the important subject in channel coding areas.Low density parity check（LDPC）code is a forward error correction code with super error correction performance and very low decoding complexity,which is widely used in many communication research and standards. In this paper, a CRC-LLR-BP decoding method is analyzed,which combine LDPC and CRC check for joint coding.In AWGN channel, 1024 yards Iong and 1/2 code rate,the algorithm is simulated and verified.The results show that the above algorithm has better decoding performance compared with the traditional BP algorithm, LLR-BP algorithm and minimum sum algorithm under the same SNR. Secondly, researched single-carrier frequency domain equalization system. In this paper, building the single-carrier frequency domain equalization system with the above LDPC code to comparative analysis the performance curves of the system under different modulation modes including QPSK modulation and 16QAM modulation.

Keywords： Signal and information processing LDPC CRC CRC-LLR-BP SC-FDE