A graph theory based scheduling algorithm For MIMO-CDMA systems using zero forcing beamforming

We propose efficient scheduling algorithms for down-link MIMO-CDMA systems using zero forcing beamforming to achieve high system throughput with low computational complexity. Based on a graph theoretical approach, we propose to represent the system as a graph and to formulate the scheduling problem as the maximum weight k-colorable subgraph problem. The proposed algorithms make use of two heuristic solutions to find the scheduled users in each time slot in an acceptable polynomial time. We evaluate the efficiency of the proposed schedulers and the results demonstrates that it can achieve near-optimal performance with very low complexity compared to the optimal exhaustive search.