Performance Analysis of Downlink OFDMA Frequency Scheduling with Limited Feedback

Opportunistic user allocation based on limited feedback information has been shown to offer significant enhancement for wireless multiple access communications. In this paper, theoretical analysis of user allocation in downlink orthogonal frequency division multiple access (OFDMA) with limited feedback is presented. The performances of resource allocation based on two feedback methods are analyzed and compared. We consider feedback based on the resource-wise SNR quantization and the ordered best-M feedback strategy, where the M best resources are informed to the transmitter. Exact bit error probability (BEP) expressions and analytical outage capacity calculus are presented for the both feedback strategies. Results indicate that significant allocation gain can be achieved with very limited feedback in wideband OFDMA systems. To achieve this allocation gain, we combine multiple resource selection and feedback strategies.