An efficient multiple access scheme for dynamic subband allocation in OFDMA system

Dynamic subcarrier allocation is a promising technique to improve signal quality and system capacity of OFDMA system, especially in frequency selective radio channels. We focus on dynamic subband allocation in OFDMA system because of the low signaling overhead, low complexity of multi-user receiver, and good multiple access interference (MAI) performance. In this paper, we propose an efficient centralized control scheme in multiple access protocol to resolve collision of subband application among multiple asynchronous users. Subband handover is employed in the multiple access protocol to track changes of frequency selectivity of radio channel. Simulation results show that the scheme effectively improves the performance of average bit error rate (BER) of multiple users and system capacity. The improved dynamic subband allocation scheme improves the system performance and ensures reliable communications over asynchronous frequency-selective multiple user channel.