Performance of uncoded space-time labelling diversity over dual-correlated Rayleigh-fading channels

Abstract

Uncoded Space-Time Labelling Diversity (USTLD) is a recent technique to improve error performance in multiple-input, multiple-output (MIMO) systems. Standard MIMO systems assume that channels between transmit and receive antennas are independent and identically distributed (i.i.d.), and thus, uncorrelated. This assumption is also made in previous works on USTLD. However, in practice, if antennas are spaced closer than half a transmission wavelength to each other, channels become correlated. This motivates the study in this paper of the performance of USTLD under correlated channel conditions. An analytical expression for the upper bound of the average bit error rate (BER) in the presence of correlated fading is derived. This expression is validated using results from Monte Carlo simulations, which show a tight fit in the high signal-to-noise ratio (SNR) region. Results presented confirm that channel correlation adversely affects the BER of USTLD for both 16QAM and 64QAM. Interestingly, results also indicate that USTLD is more sensitive to channel correlation than comparable standard MIMO schemes.