Differential space-time modulation using DAPSK

A new differential space-time modulation using diversity-encoded differential amplitude and phase shift keying (DAPSK) is proposed for the multiple-input multiple-output (MIMO) system over independent and identically distributed (iid) time-correlated Rayleigh fading channels. An asymptotic maximum-likelihood (AML) receiver is developed for diversity-encoded DAPSK. The bit error probability (BEP) upper bound is analyzed over iid time-correlated Rayleigh fading channels. Moreover, an approximate BEP upper bound is also derived for iid time-invariant Rayleigh fading channels with high received signal-to-noise power ratio. A design criterion in terms of this approximate bound is developed to determine the appropriate diversity encoding coefficients for the proposed DAPSK MIMO system. Performance results show that the AML receiver for diversity-encoded DAPSK offers the best error performance among conventional noncoherent MIMO systems.