IMPROVED ERROR PERFORMANCE USING PARTIAL-RESPONSE SIGNALING FOR MPSK IN FADING CHANNELS

In this paper, we consider the classical bandwidth efficiency improvem ent technique which is the partial response signaling (PRS), especiall y 1 + D duobinary signaling, for M-ary phase shift keying (MPSK) modul ation transmitted over fading channels. We only consider the case wher e interleaving/deinterleaving is employed to further combat the fading and assume that the ideal channel state information is available. Ana lytical bit error probability upper bounds are derived using the trans fer function bounding technique for both the partial response coded an d uncoded MPSK cases. One interesting result, obtained from the compar isons, is that the partial response coded MPSK outperforms the uncoded MPSK in the fading environment, for signal-to-noise ratio values grea ter than a threshold, when the soft decision Viterbi decoder is used, contrasting to the additive white gaussian noise channels. In order to demonstrate the validity of this result, the asymptotic bit error pro bability expression for trellis codes in the presence of fading, given in [3], is considered. Computer simulations done for the Rayleigh fad ing case, also verify this aspect of the partial response signaling.