Adaptive feedback algorithm for OFDMA systems

In this paper, a new feedback scheme is proposed for downlink OFDMA system with frequency domain packet scheduling to achieve multiuser diversity. Recent work showed that the multiuser diversity can be gained by using the so-called average best-M feedback scheme where bit-mask indicating the identification of best M subcarriers together with the average channel quality indicator of those subcarriers are reported. It has been shown that the performance of the average best-M is highly sensitive to the choice of the M value for each number of users. In this paper, an adaptive feedback scheme in which the bit-mask of feedback subcarriers is dynamically adjusted when the number of users changes is proposed. The simulation results show that the proposed scheme achieves the same performance as the average best-M scheme when the number of feedback subcarriers is optimally selected for each number of users.