On bootstrap iterative Viterbi algorithm

A bootstrap iterative Viterbi algorithm (BIVA) is proposed based on a bootstrap structure. Two different modifications are then considered for both very short size blocks (say 100-250 bits) and the medium size blocks (1000-3000 bits). It shows that the iterative decoding can be achieved by using the conventional Viterbi algorithm, which does not require the noise variance estimation. The numerical results show the significant performance improvement over the standard Viterbi algorithm is possible. For a block length of 1500 bits and with a 32 state VA, the 2D BIVA can achieve a bit error rate of 2/spl times/10/sup -5/ at an E/sub b//E/sub 0/ of 2.3 dB away from the Shannon limit. For both information block lengths of 1944 and 11970 bits, in term of its performance respect to the Shannon limit and the Shannon sphere packing bound, the 2D-BIVA is about 0.2-0.3 dB worse than the best known rate 1/2 JPL turbo codes of similar information block sizes. With some simple modifications, most of current systems (where the Viterbi algorithms used) can benefit significantly from this iterative decoding procedure.