A low-complexity adaptive bit and power allocation algorithm for MIMO-OFDM systems

In this paper, we present a low-complexity adaptive bit and power allocation algorithm for MIMO-OFDM systems. The MIMO-OFDM channel can be decomposed into a group of parallel subchannels by singular value decomposition (SVD) [Branka and Vucetic, 2003]. To minimize the overall transmit power, we carry out a fixed bit and power allocation over these subchannels by exploring the characteristics of the ordered subchannel gains. The fixed bit and power assignment can be determined by greedy algorithm at the initial stage and utilized without change throughout the data transmission process. Simulation results show that the proposed algorithm has less than 1 dB performance loss relative to the optimal algorithm when the number of OFDM subcarriers is large, but drastically reduces the complexity.