Adaptive Resource Allocation with Adaptive Beamforming for MIMO-OFDMA System with a Priority User

In this paper, we propose a new resource allocation scheme for MIMO-OFDMA systems with a priority user. With the goal of minimizing the total transmission power and exploiting spatial diversity and multiuser diversity efficiently, the proposed algorithm firstly allocates the subcarrier to the priority user, and it selects the N relatively largest eigenvalues of all subcarriers and allocates the best subcarrier to the priority user adaptively until its data rate is fulfilled. Then the remaining subcarriers are dynamically allocated to the other users without considering their QoS requirements. Finally, the proposed algorithm reallocates some subcarriers from the satisfied users to the unsatisfied users to guarantee all users´ QoS requirements and the additional power because of the subcarriers reallocation is also minimized. Simulation results confirm the effectiveness of the proposed algorithm.