Research on Unequal Error Protection with Irregular LDPC and Application on Image Transmission

Irregular LDPC codes outperform regular LDPC codes with the same code length and rate and exhibit the inherent UEP performance because of the variant degrees of the variable nodes. According to the level of the protection of the transmitted image, a UEP algorithm on image transmission utilizing the irregular WIPC-LDPC codes is proposed in this paper. The algorithm adaptively segments the image into different size of sub-blocks with different level of significance and encodes the different blocks with variant irregular LDPC codes where the lower rate of codes is matching to the more significant blocks and the higher rate of codes to the least significant blocks. Then, every sub-block is performed by 8*8 DCT and the selected coefficients expressed by 8 bits are encoded by the corresponding irregular LDPC codes where the important information bits could successfully be mapped to the elite bits of the Irregular LDPC code which have the large degree. The number of the selected coefficients is chosen by the quality constant reflecting the quality of the recovery image. Simulation results show that the transmission quality of the image may be effectively improved by the proposed algorithm.