Symbol-by-symbol MAP decoding algorithm for high-rate convolutional codes that use reciprocal dual codes

A symbol-by-symbol maximum a posteriori (MAP) decoding algorithm for high-rate convolutional codes applying reciprocal dual convolutional codes Is presented, The advantage of this approach is a reduction of the computational complexity since the number of codewords to consider is decreased. All requirements for iterative decoding schemes are fulfilled. Since tail-biting convolutional codes are equivalent to quasicyclic block codes, the decoding algorithm for truncated or terminated convolutional codes is modified to obtain a soft-in/soft-out decoder for high-rate quasi-cyclic block codes which also uses the dual code because of complexity reasons, Additionally, quasi-cyclic block codes are investigated as component codes for parallel concatenation, Simulation results obtained by iterative decoding are compared with union bounds for maximum likelihood decoding, The results of a search for high-rate quasi-cyclic block codes are given in the Appendix.