A window based channel allocation algorithm for two-way AF relay OFDMA systems

A window based channel allocation scheme is conceived for two-way AF relay aided OFDMA systems. Two users communicating with each other via a specific relay constitute a user-pair. At most one channel index with its channel gain lying within a window, given the left and the right thresholds, is reported to the relay by each user at a time. If two users of a user-pair send non-identical channel indices, one of them makes a concession to match the channel index sent by its partner. Furthermore, all user-pairs with different QoS requirements can employ the concession process with the aid of scheduling scheme parallelly to attain optimal channel allocation. Simulation results demonstrate that the proposed algorithm with limited feedback of channel state information (CSI) achieves asymptotic system performance compared with the full CSI feedback based scheme.