Different Soft decision decoding approaches for block codes which refine the Hard decision decoding have been reported. These approaches have varying degrees of complexity and performance enhancement. The Reliability Level List (RLL) based decoding scheme for block codes directly uses the reliability of the received bit with corresponding dividend in decoding. With this scheme it has become possible to identify the Target Codeword (TCW) directly obviating the need for forming an intermediate set of candidate codewords and then selecting the decoded codeword from them. This opens up the possibility of exploring a comprehensive generalization of the RLL concept for any block code and any baseband scheme. Such a generalization for block codes with M-QAM signaling scheme is established in the paper.
Dr. Yamuna B. and T.R, P., “Reliability Level List-Based Decoding of Multilevel Modulated Block Codes”, International Journal of Information and Communication Technology, vol. 9, no. 3, pp. 366-376, 2016.