Linear diversity analysis for QAM in Rician fading channels

An exact and general closed-form expression of the Bit Error Rates (BER) for rectangular type of Quadrature Amplitude Modulation (QAM) over slow, flat, Rician fading channels are derived analytically when the Maximal-Ratio Combining (MRC) technique is applied to mitigate degradation from multipath fading and fluctuation. The paper starts with a non-traditional expression of BER for a single-link QAM signal in AWGN channel, followed by averaging over the additional effects of channel fading and diversity combining to complete the analysis. The analysis for Rayleigh fading is included as a special case. Finally, the derivation also covers the more popular square type of QAM systems as degenerated case.