Publication

Abstract : In BCH coded schemes the reliability information available with the demodulated bits can be effectively used for soft decision decoding (SDD) to improve signal to noise ratio performance. Chase algorithms, their adaptations, and modifications available for SDD trade complexity for performance to different levels. A new iterative algorithm - Reliability Level List based Direct Target Codeword Identification Algorithm (DTCI) - is proposed in the paper; the algorithm yields the best that is possible with SDD. The concept of reliability level list (RLL) introduced in the paper is central to the application of the algorithm. At every stage of the iterative process followed, the algorithm uses the reliability information of the bits and identifies the next most likely candidate word to be examined. This ensures that the correct decoded codeword is identified through the shortest number of steps. Detailed simulation studies with different BCH codes amply bring out the effectiveness and superiority of the algorithm.