Research On Zigzag-based Systematic Irregular GLDPC Codes

An upsurge in studying channel coding was set off since turbo code was proposed in 1993. In the efforts of many researchers, channel coding technology, not only in coding theory but also in its applications, has achieved fruitful results including Turbo codes, near the Shannon limit LDPC codes and their applications of unequal error protection. Although LDPC codes have been applied to unequal error protection, there still exist some problems: higher coding complexity of LDPC codes and the mapping problem between high degree variable nodes of irregular LDPC codes and the "elite" information nodes. Therefore, it is great significant to research and design a coding structure of better BER performance and its application in unequal error protection. In this paper, we focus our researches on the theory and application of Zigzag-based Systematic Irregular GLDPC codes through a combination method of theoretical analysis and computer simulation. The main works are summarized as follows:1. Preliminary Studies on Zigzag-based Systematic Irregular GLDPC codes are made. Firstly, a new class of codes, termed Zigzag-based Systematic Irregular GLDPC codes, is proposed. Secondly, the method of degree distribution optimization of ZS-IGLDPC codes in the AWGN channel is proposed and we design two optimized degree distribution sequences whose code rate is 0.5. Finally, the designed codes are simulated and simulation results show that ZS-IGLDPC codes have good BER performance for medium code length.2. Preliminary Studies on unequal error protection of ZS-IGLDPC codes are made. Firstly, analysis and simulations on how the parameters of ZS-IGLDPC codes affect the performance of unequal error protection schemes are made. Secondly, the parameter selection criteria of UEP schemes on ZS-IGLDPC codes are proposed. Finally, the performance comparison between the UEP schemes of ZS-IGLDPC codes and other UEP schemes is made. And UEP experiment in which MPEG-2 video stream as a carrier is done. Simulation and experimental results show that the UEP schemes which are obtained according to the parameter selection criteria of UEP schemes on ZS-IGLDPC codes are effective in unequal error protection.