An ARQ Scheme with Memory and Integrated Modulation

In this paper, the integration of the modulation operation in an automatic-repeat-request scheme, using error-detecting codes, is analyzed. A new protocol is described, in which the modulation operation facilitates the recovery of the transmitted code word. The results show a net improvement in the throughput of the automatic-repeat-request scheme, particularly for mean and high error-rate conditions. Continuous-phase-frequency shift keying modulations, which present a low bandwidth occupancy, are particularly considered.