Adaptive resource allocation for multiaccess MIMO/OFDM systems with matched filtering

In this letter, we propose an adaptive resource-allocation algorithm for multiaccess multiple-input multiple-output/orthogonal frequency-division multiplexing systems. The proposed algorithm endeavors to maximize the system power efficiency, given that the users' quality of service (QoS) requirements, specified by bit-error rate and data rate, are satisfied. Subcarrier allocation, power distribution, and modulation for multiple users are jointly optimized according to users' channel states and QoS requirements. To avoid the joint optimization of resource allocation and beamforming, matched-filter-based receivers are employed at the base station, with cochannel interference being mitigated through dynamic subchannel allocation. A neighborhood search scheme is further developed to obtain a good allocation solution with reasonable computational efforts. Our results show that the proposed algorithm is able to achieve significant enhancement in the system power efficiency due to the successful exploitation of multiuser diversity, as well as channel variations in the time, frequency, and space domains.