User Selection and Resource Allocation for Multi-User MIMO-OFDM Systems with Downlink Beamforming

In this paper, a multi-user MIMO-OFDM system with downlink beamforming technique is considered. We aim at minimizing the total transmission power while fulfilling each user´s data rate and bit error rate (BER) requirement. This problem is formulated as a linear optimization problem in our paper. Since the optimal solution obtained from integer programming (IP) approach can hardly be implemented due to its high computational complexity, we present a heuristic user selection and resource allocation algorithm. Simulation results show that compared with existing SDMA-OFDM systems with or without resource allocation, our algorithm achieves significant performance improvement. The performance of the proposed heuristic algorithm is very close to that of the optimal solution.