Frequency Selective OFDMA Scheduler with Limited Feedback

Orthogonal Frequency Division Multiple Access (OFDMA) is the preferred multiple access scheme for future broadband cellular systems as it provides high spectral efficiency. The choice of OFDMA scheduler and the amount of channel quality feedback from users together determine the achievable throughput and fairness. Channel quality reporting by all active users across the entire carrier bandwidth may result in significant uplink overhead. This paper discusses the performance of two possible OFDMA schedulers based on the class and channel condition weighted proportionally fair scheduler. The impact of different scheduler parameters are investigated. The paper then analyzes the performance of the top-M scheme, which is a candidate channel quality overhead reduction proposal being discussed in 3GPP Long Term Evolution. It is shown that the top-M scheme, with significantly lower uplink overhead, provides similar performance as the case where the network has complete channel quality information.