Bayesian approach for erasure insertion in frequency-hop multiple-access communications with selective fading

In this paper, we propose a decision rule for symbol erasure insertion in a dispersive propagation environment based on Bayesian decision theory. The method is applied to frequency-hop communications with Reed-Solomon coding and error-and-erasures decoding. The proposed algorithm is based on decisio n feedback to eliminate statistical dependence among the envelope detectors ' outputs of an M-ary frequency-shift keying noncoherent demodulator. The p erformance is analyzed for fading channels with different levels of frequen cy selectivity and synchronous multiple-access interference. It is shown th at the use of memoryless decision rules results in complete inefficiency in such channel conditions, whereas the proposed rule provides large coding g ains even for severe selectivity. The performance sensitivity with respect to the estimation of the power delay profile denotes high robustness of the proposed approach, provided that the selection is somewhat overestimated. Sensitivity results about error propagation due to decision feedback are al so given.