Quadrature space shift keying performance with dual-hop AF relay over mixed fading

Quadrature space shift keying (QSSK) modulation combined with cooperative relaying improves the reliability in communication and enhances the overall spectral efficiency. Here, QSSK scheme is analyzed for multiple-input multiple-output (MIMO) wireless communication system with dual-hop amplify-and-forward (AF) relaying systems over asymmetric mixed Rayleigh/Rician and symmetric Nakagami-m/Nakagami-m fading channels. Analytical expressions for cumulative distribution function (CDF) of the end-to-end signal-to-noise ratio are derived and used to evaluate the average bit error probability (ABEP) of QSSK modulation in mixed asymmetric and symmetric fading channels. The obtained ABEP expression is in the form of Whittaker function, which can be numerically evaluated using its numerical or series representation. Numerical and simulation results are presented to illustrate the impact of fading parameters on the system performance.