Novel two-level and three-level 8-PSK modulation codes with more UEP flexibility for Rayleigh fading channel

Two different structures for combining multilevel coding and 8-PSK modulation are proposed. With rather low decoding complexity and short end-to-end delay, surprisingly good performance is achieved. By choosing different coded modulation (CM) structures and different component generalized array codes (GACs), a flexible unequal error protection (UEP) profile is obtained. Increased error protection can be provided for 29% to 100% of important information data, while in conventional multilevel schemes, this privilege is enjoyed by less than 50% of important information bits. A proposed novel scheme of two-level 8-PSK modulation codes gains great advantage over the three-level ones by its low decoding complexity, short time delay and good bit error performance. Results show that more than 27 dB gain is achieved by two-level 8-PSK code (12, 8, 3) (24, 15, 4) at a bit error rate of 10 ^-5. This scheme has only 16 states in its staged decoder