Opportunistic downlink scheduling for multiuser OFDM systems

We consider the problem of downlink scheduling for multiuser OFDM (orthogonal frequency division multiplexing) systems. We derive optimal scheduling policies under three QoS/fairness constraints - temporal fairness, utilitarian fairness, and minimum-performance guarantees. To calculate these optimal policies, we interpret the problem as a maximal bipartite matching problem. To solve this problem, we apply the modified Hungarian algorithm and a practical suboptimal algorithm. The simulation results show that our schemes achieve significant improvement in system performance compared with a non-opportunistic scheme.