Joint selection combining and power loading transmission with adaptive M-QAM in multi-channel system

In this paper, we propose and adaptive M-ary Quadrature Amplitude modulation (M-QAM) transmission scheme that jointly uses selection combining and power loading over multiple independent and identically-distributed (i.i.d) Rayleigh fading channels in multi-channel systems. We derive exact closed-form expressions of the performance of the proposed scheme in terms of the spectral efficiency, the average BER and the outage probability. Numerical results show that our proposed hybrid scheme offers high spectrial efficiency and lower outage probability than the conventional scheme and other hybrid schemes presented in the literature, is more reliable in low SNR region as well.