On sequential decoding for the Gilbert channel

-It is well-known that the computational performance of sequential decoding deteriorates drastically when channel errors occur in clusters. Hagenauer suggested a feasible modification of sequential decoding which uses a burst-tracking method for better performance. At each step he considers the channel to be memoryless, but with varying probability of error. A different way of using sequential decoding to exploit the memory of a Gilbert channel is presented. A Fano-like metric matched to this channel is used. The methods are investigated by simulating sequential decoding utilizing the stack algorithm. These simulations confirm the feasibility of the proposed techniques. Manuscript received December 15, 1986; revised November 3, 1987. This work was supported in part by the Royal Swedish Academy of Sciences and the Royal Swedish Academy of Engineering Sciences in liaison with the Academy of Sciences of the USSR and in part by the Swedish Board for Technical Development under Grant 85-3303. This work was partially presented at the Second Joint Swedish-Soviet International Workshop on Information Theory, Granna, Sweden, April 1985, and was presented at the IEEE International Symposium on Information Theory, Ann Arbor, MI, October 6-9, 1986. V. Sidorenko and K. Sh. Zigangirov are with the Institute for Problems of Information Transmission, USSR Academy of Sciences, Ermolovoy 19. Moscow GSP-4, USSR. R. Johannesson is with the Department of Information Theory, University of Lund, P.O. Box 118, S-221 00 Lund. Sweden. IEEE Log Number 8823990. 0018-9448/88/0900-1058$01.~ 01988 IEEE IEEE TRANSACTIONS ON INFORMATION THEORY, VOL. 34, NO. 5, SEPTEMBER 1988 1059