Performance of rotated PSK modulation in Nakagami-m fading channels

This paper studies performance of Rotation & Component Interleaving Diversity (RCID) over frequency non-selective and slowly Nakagami-m fading channels for arbitrary fading parameter m. Briefly, RCID is to rotate signal constellation and use component interleaving at the transmitter and de-interleaving at the receiver. First, Symbol Error Probability (SEP) of the system is derived by using moment generating function based approach and optimum rotation angles minimizing SEP are found for M=2,4,8 Phase Shift Keying (PSK). Upper bound is also derived in order to obtain asymptotic diversity order. The analytical results are validated by the simulation results. Then, RCID is applied on receive antenna combining techniques and their error performances are studied by the simulations. The optimum rotation angles are also obtained for combining techniques with rotated M-PSK modulation. Results show that performance of the systems improves significantly and diversity order of the systems doubles as compared to those of the equivalent unrotated systems.