Near-Capacity Turbo Coded Soft-Decision Aided DAPSK/Star-QAM

Low-complexity non-coherently detected Differential Amplitude and Phase-Shift Keying (DAPSK) schemes constitute an ideal candidate for wireless communications. In this paper, we derive the soft- output probability formulas required for the soft- decision based demodulation of DAPSK, which are then invoked for Turbo Coded (TC) transmissions. Furthermore, the achievable throughput characteristics of the family of M-ary DAPSK schemes are provided. It is shown that the proposed 4-ring based TC assisted 64-ary DAPSK scheme achieves a coding gain of about 4.2 dBs in comparison to the identical-throughput TC assisted 64-ary Differential Phase-Shift Keying (64-DPSK) scheme at a bit error ratio of 10^-5.