Iterative decoding in convolutionally and turbo coded MFSK/FH-SSMA systems

This paper presents an iterative decoding method in the coded MFSK (multilevel frequency shift keying)/FH-SSMA (frequency hopping-spread spectrum multiple access) system. The kernel of the system, which is a symbol APP (a posteriori probability) calculator, accepts channel values and a priori information from the channel decoder and generates reliability values of the received symbols. The channel decoder also makes reliability outputs using the reliability values from the symbol APP calculator. Iterative decoding is performed by repeating this process. Simulation results reveal that the channel coded system with iterative decoding in the FH-SSMA system can reduce the BER significantly, thereby accommodating more users.