Performance of W-CDMA systems with rectangular signalling in OSTBC MIMO generalised nakagami-m fading channels

The performance of combined temporal multipath diversity with statistically independent branches and spatial antenna diversity with arbitrarily correlated branches is investigated. A downlink wide-band code-division multiple access system employing orthogonal space-time block coding multiple-input-multiple-output communications is considered. The performance is quantified in terms of the average symbol error probability (SEP) of coherent arbitrary rectangular quadrature amplitude modulation in Nakagami-m fading with arbitrary statistics. Through the analysis, new expressions for the average SEP are derived under the generalised system model described above. Specifically, the considerations of the combined path and space diversity model, the arbitrary correlation profile among spatial diversity branches, and the arbitrary statistics of Nakagami-m fading processes are the main aspects that make the system model herein generalised as compared to previous ones. Furthermore, for this generalised system model, the consideration of distinct in-phase and quadrature decision distances as well as modulation orders in the rectangular signalling constellation through the analysis provide additional enhancements on some existing results. Numerical and simulation results are presented to demonstrate the enhanced validity of the analytical development.