Multi-user MIMO-OFDM with Adaptive Resource Allocation over Frequency Selective Fading Channel

In this paper, a practical and efficient adaptive sub-carrier, power and bit allocation algorithm for multi-user MIMO-OFDM systems is described. Assuming perfect knowledge of the channel state information (CSI) on the transmitter, we explore the problem of minimizing the total transmit power with constant overall bit rate requirement. The scheme proposed here attempts to make the MIMO-OFDM systems more flexible and robust to channel variations. To minimize the total transmit power, we assign each OFDM sub-carrier according to the square of the maximum eigenvalue of the channel frequency response matrix. We also provide a low complexity algorithm based on the greedy algorithm for the adaptive bit and power allocation over the frequency selective fading channel. Computer simulations are conducted to demonstrate the performance of the proposed scheme comparing with some other adaptive schemes in the terms of bit error rate (BER).