STBCs with orthogonal decoder for highly time-selective channels

We present bit-error-rate (BER) analyses of Orthogonal Space-Time Block Codes (O-STBCs) and their modified version (MO-STBCs) combined with the Orthogonal Decoder (OD) over uncorrelated and time-selective fading channels of generalized statistics. First, we quantify the effective diversity achieved by STBCs (O-STBCs and MO-STBCs) by resorting to a statistical characterization of the diversity gain of both schemes with OD. We, then, expand the theoretical BER expressions of O-STBCs, derived for the block fading channels, to MO-STBCs with OD in a more practical time-selective fading channel with Gray-code-mapped M-ary phase-shift-keying (PSK) modulation and M-ary quadratic-amplitude modulation (QAM). Moreover, through our BER expressions, we pinpoint the relationship between the effective diversity and BER performance of STBCs with OD, which elucidates the reason why MO-STBCs with OD architecture is very robust to the highly time-selective fading expected in 4th Generation Wireless Networks (4G). Finally, the theoretical results in conformity with the simulated ones demonstrates the accuracy of our analysis.