The effects of multipath fading and transmit diversity on adaptive modulation in a frequency selective Rayleigh fading channel

In this paper, the average bit error rate (BER) and the average throughput (BPS) are derived for adaptive modulation (AM) combined with transmit diversity (TD) in a frequency selective Rayleigh fading channel. The effects of multi path fading and TD on AM are investigated based on the derived BER and BPS expressions. The results show that the diversity effect by multipath fading can be positive or negative depending on the average SNR and that the performance of AM can be improved by combining TD scheme, especially when there are a few multipath components.