Dong, ZhichengFan, PingzhiZhou, WeixiPanayırcı, Erdal2019-06-272019-06-2720121978146730990597814673098821550-22521550-2252https://hdl.handle.net/20.500.12469/928https://doi.org/10.1109/VETECS.2012.6239931In this paper the effect of power and rate adaptation on the spectral efficiency of orthogonal frequency division multiplexing (OFDM) systems using M-ary quadrature amplitude modulation (MQAM) is investigated in the presence of the fast fading channels under power and instantaneous bit error rate (BER) constraints. A lower bound on the maximum spectral efficiency of adaptive OFDM/MQAM systems is obtained together with a closed-form expression for the average spectral efficiency of adaptive OFDM systems. Theoretical and numerical results show that the adaptive MQAM/OFDM systems under fast fading channel have substantial gain in spectral efficiency over the non-adaptive counterparts.eninfo:eu-repo/semantics/openAccessOrthogonal Frequency Division Multiplexing (OFDM)Intercarrier Interference (ICI)Power and rate adaptationSpectral efficiencyHigh mobilityConference ObjectWOS:00030933850007610.1109/VETECS.2012.62399312-s2.0-84865011402N/AN/A