BIT-interleavingin in FH/SSMA systems

FH/SSMA systems with M-ary FSK modulation and soft-decoding convolutional codes are investigated in this paper. Two mapping schemes between binary coded bits and M-ary FSK symbols are considered: one with bit-interleaving and the other without bit-interleaving. Simulation results show that convolutional codes without bit-interleaving outperform convolutional codes with bit-interleaving when multiple access interference is the main source of error. More-over, the non-interleaving soft-decoding scheme provides a significant performance improvement over existing diversity combining schemes for Reed-Solomon codes with error-and-erasure decoding.