Performance evaluation of some ARQ schemes using efficient modulation techniques and noncoherent detection

The performance of generalized automatic repeat request (ARQ) schemes with continuous-phase frequency-shift-keying (CPFSK) modulation schemes and noncoherent detection is analyzed. In the proposed schemes, each bit of a block is transmitted m times consecutively to increase the transmission reliability. Efficient CPFSK schemes are considered because they represent a class of joint power- and bandwidth-efficient digital modulation schemes with constant amplitude, which can be coherently or noncoherently demodulated. The theoretically derived throughput is optimized for each bit´s transmitted copies. In comparison with the classical ARQ schemes, the proposed schemes provide enhanced throughput, especially under high error rate conditions. The use of the noncoherent detection greatly reduces the receiver implementation complexity. The schemes can also be used when coherent detection is required