A very low complexity block turbo decoder composed of extended Hamming codes

Abstract

This paper presents a very low complexity block turbo decoder composed of extended Hamming codes. New efficient complexity reduction algorithms are proposed including simplifying the extrinsic information computation and soft inputs updating algorithm. For performance evaluation, [eHamming (32,26,4)]/sup 2/ and [eHamming (64,57,4)]/sup 2/ block turbo code transmitted over an AWGN channel using BPSK modulation are considered. Extra 0.3 dB to 0.4 dB coding gain is obtained if compared with the scheme proposed in Pyndiah et al., (1996), and the hardware overhead is negligible. The complexity of our new block turbo decoder is about ten times less than that of the near-optimum block turbo decoder with a performance degradation of only 0.5 dB. Other schemes such as reduction of test patterns in the Chase algorithm and memory saving techniques are also presented.