An Improved Belief Propagation Based Decoding Algorithm for RS

• Main Authors: Kuo, Hsin-Chung, 郭欣銓
• Other Authors: Wang, Chung-Hsuan
• Format: Others
• Language: en_US
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/51800466190113983198

碩士 === 國立交通大學 === 電信工程系所 === 97 === Recently, Reed-Solomon (RS) codes have been the error-correction codes (ECCs) of choice in many communication systems because of their ability to correct burst errors and the availability of efficient algebraic hard decision decoding algorithms. It is known that soft-decision decoding (SDD) of RS codes provides significant performance gain over hard decision decoding (HDD), but most systems still are based on HDD because of the high complexity of SDD. In 2006, Jiang and Narayanan (JN) proposed an iterative soft-in soft-out decoding algorithm of RS codes by adapting the parity check matrix. The JN algorithm can avoid the problem of check node saturation and the error propagation from the least reliable positions, but the drawback of the JN algorithm is to over believe the messages from the most reliable positions. In this thesis, we first analyse the reason of decoding failure in the JN algorithm. Based on our discussions, we propose a new algorithm to avoid the influence of errors in most reliable positions in the JN algorithm and improve the decoding performance. The basic idea of our algorithm comes from the OSD algorithm, which was proposed in 1995 by Fossorier and Lin. We modify the received vector before the JN algorithm. Some errors in the most reliable positions may be reduced. Therefore, the influence of errors in high reliable positions can also be reduced. Compared with the original JN algorithm, the proposed algorithm has about a 0.5-1.2dB coding gain while decoding RS codes in the additive white Gaussian noise (AWGN) channel under binary phase shift keying (BPSK) modulation.