Distributed source coding using non binary LDPC

Abstract

In this thesis we have extended non binary low-density parity-check (LDPC) codes, developed for channel coding, to be used for source coding to compress correlated non binary sources. Focusing on the asymmetric case of compression of an equiprobable memoryless non binary source with side information at the decoder, the approach is based on viewing the correlation as a channel and applying the syndrome concept. The encoding and decoding procedures are explained in detail. The results obtained through simulations showed that the non binary compression scheme gives symbol error rates of zero for correlation coefficients greater than or equal to 0.80 for a compression rate of 1/2. For a compression rate of 3/4 the non binary compression scheme gives symbol error rates of zero for correlation coefficients greater than or equal to 0.65. In comparison the binary compression scheme gives bit error rates of zero for correlation coefficients greater than or equal to 0.90 for compression rate of 1/2. For compression rate of 3/4 the binary compression scheme gives bit error rates of zero for correlation coefficients greater than or equal to 0.75. This shows that the non binary compression scheme handles sources with relatively low correlations better than the binary scheme.