Reduced complexity sliding window BCJR decoding algorithms for turbo codes

Abstract

In decoding the turbo codes, the sliding window BCJR algorithm, derived from the BCJR algorithm, permits a continuous decoding of the coded sequence without requiring trellis termination of the constituent codes and uses reduced memory span. However, the number of computations required is greater than that of BCJR algorithm. In this paper, we propose an efficient sliding window type scheme which maintains the advantages of the conventional sliding window algorithm, reduces its computational burdens, and improves its BER performance by allowing the window to be forwarded in multi-step. Simulation results show that the proposed scheme outperforms the conventional sliding window BCJR algorithm with reduced complexity.