Adaptive modulation over nonlinear time-varying channels

This paper proposes a simple adaptive modulation scheme over nonlinear time-varying channels equipped with high power amplifiers (HPAs). The paper includes the probability of bit error rate (BER) analysis of M-QAM transmission over nonlinear channels, which is the key factor in designing adaptive modulation. The paper includes performance comparison of adaptive modulation over linear and nonlinear channel with different normalized Doppler frequencies. The analysis is supported with simulation results. Results show that the nonlinearity affects the overall system performance; however, the adaptive modulation scheme allows significant spectral improvement over the classical non-adaptive system.