Decision-feedback differential detection for 16DAPSK transmitted over Rician fading channels

In this paper, a novel decision-feedback differential detection (DF-DD) scheme based on linear prediction is proposed for 16-level differentially encoded amplitude-phase-shift keying (16-DAPSK). Unlike previously proposed DF-DD schemes, this scheme not only provides a performance gain over conventional differential detection (DD) under additive white Gaussian noise (AWGN) conditions but also under general Rician fading conditions. A further important advantage of the novel scheme is that it does not degrade under frequency offset. The linear predictor coefficients may be updated using the recursive least-squares (RLS) algorithm, which can start blind, i.e., without a priori knowledge about the channel statistics and without a training sequence. This makes the scheme attractive for application in mobile communications since the statistics of the nonstationary mobile channel can be tracked