Adaptive Transmission in a MIMO-OFDM System in Nakagami-m Fading Channels

The goal of fourth generation (4G) mobile communications system is to seamlessly integrate a wide variety of communication services such as high speed data, video and multimedia traffic as well as voice signals. One of the promising approaches in 4G is the Adaptive Orthogonal Frequency Division Multiplexing (AOFDM) technique. In Multiple Input Multiple Output (MIMO)OFDM, adaptive transmission scheme is employed according to channel fading conditions in OFDM to improve the performance. In this paper, adaptive modulation is only considered. To further enhance the system performance, convolutional coding can be employed to the OFDM system. The obtained results show that significant improvement in bit error rate and average spectrum efficiency can be achieved demonstrating the superiority of the adaptive modulation schemes compared to fixed transmission schemes.