An explicit and unified error probability analysis of two detection schemes for differential unitary space-time modulation

Abstract — The performance of two demodulation schemes for the differential unitary space-time modulation (DUSTM), the standard differential demodulation and decision-feedback demodulation, are analyzed in a unified approach under Rayleigh time-varying channels. We derive compact expressions for the pairwise error probability (PEP) and its upper and lower bound. Our analysis justifies the conventional design criteria on DUSTM constellations for more general channel models and demodulation schemes. We formulate a simple expression of the effective SNR that captures the time correlation of fading, the length of the observation window, and the noise variance. Based on the derived results for general DUSTM, we further obtain an explicit closedform expression of the PEP for the specific constellation proposed by Tarokh and Jafarkhani [12]. We also show that this specific DUSTM allow efficient decision-feedback detection. I