Precoded Differential Orthogonal Space-Time Modulation Over Correlated Ricean MIMO Channels

In this paper, we study a differential system employing orthogonal space-time block codes (OSTBC) with -PSK, -PAM, and -QAM constellations, over arbitrarily correlated Ricean fading channels. The symbol error rate (SER) performance analysis of such a differential system is performed using a memoryless precoding matrix at the transmitter. Monte Carlo simulations are carried out to verify the validity of the SER expressions. The SER formulas can predict the behavior of differential system closely for moderate to high values of signal to noise ratio (SNR). The proposed precoded differential codes differ from the previous works by: 1) the precoded differential code is proposed for the arbitrarily correlated Ricean channels, whereas, existing work is applicable for Rayleigh fading channels using Kronecker model with transmit correlation only. 2) the previous work is applicable to the OSTBC with -PSK signal constellations only, whereas, the proposed precoded differential coding works with -PSK, -QAM, and -PAM constellations. 3) the precoder design is proposed to minimize the approximate SER, whereas the previous precoder is based on minimizing an upper bound of the approximate SER. In addition, the proposed precoded orthogonal differential code performs better than the previously proposed eigen-beamforming based precoded differential OSTBC.