Opportunistic Periodic Feedback Mechanisms for OFDMA Systems under Feedback Budget Constraint

Adaptive modulation and coding scheme is commonly used in mobile and wireless systems to achieve high-data rates and increase system efficiency. Such adaptation invariably requires some channel information to be fed back to the base station and leads to a non negligible increase in uplink overhead. To deal with this issue, adequate feedback reduction mechanisms are mandatory especially in multiuser multicarrier systems such as OFDMA. Periodic feedback mechanisms have been proposed to significantly reduce feedback information when many users need to be scheduled in each transmission frame with constraint feedback budget. In this paper, we propose an opportunistic periodic feedback approach which exploits the hints from MAC ARQ protocol to enhance the performance of periodic feedback mechanisms. Simulation results show that our opportunistic strategy improves the performance in terms of throughput, bit error rate and MAC frame lossrate especially for high mobility scenarios.