Adaptive OFDM modulation techniques over fading channel for wireless communication systems with an 80 MHz bandwidth

The orthogonal frequency division multiplexing (OFDM) is one of the promising technologies to improve the spectral efficiency, enhance system capacity and mitigate inter-symbol interference in the wireless communication system. In this paper, we aim at the study on adaptive modulation and coding technologies for wireless system over frequency selective fading channel. This adaptive allocation algorithm assigns the sub-carriers. We are applied adaptive modulation technique to each sub-carrier to keep required BER and PER performance. The system chooses modulation among BPSK, QPSK, 16QAM and 64QAM which the estimated SNR of the sub-carrier inhabits. Adaptive modulation can improve communication performance under small SNR. The computer simulation result shows the BER, PER and Throughput performance can be improved under 30 dB of SNR region.