A low complexity soft decision decoder for linear block codes

The Chase-2 decoding algorithm is an efficient soft input hard output decoder that uses a list of most likely error patterns. The main idea behind this decoder is to use a hard decision decoder HD in 2t times, where t is the error correcting capability of the used code. The complexity of Chase-2 decoder is then of order 2t.O(HD). The choice of the HD decoder impacts considerably the complexity. In this paper, we present the Chase-HSDec decoder where we have integrated the low complexity hard decision decoder HSDec that we have recently developed as component decoder. Given its low temporal complexity comparing to their competitors, the use of HSDec in the Chasing technique, decrease the temporal complexity. Chase-HSDec is applied to decode some BCH and QR codes; the simulation results show that the proposed solution yield to good error correcting performances. The comparisons between the proposed decoder and some competitors have shown that it exceeds them. The main advantage of this decoder is that it guarantees the same performances of Chase-Berlekamp Massey decoder with reduced temporal complexity. Contrary to the Chase-Berlekamp Massey decoder which is generally used for BCH codes; it is possible to apply Chase-HSDec on other linear codes defined with their generator matrix.