Dynamic CQI resource allocation for OFDMA systems

In this paper, we propose a cross-layer dynamic CQI resource allocation (DCRA) scheme for OFDMA systems. Implemented at the base station (BS) side, DCRA algorithm chooses adaptively the mobile stations (MS) which are to send feedback to maintain their QoS constraints. Based on the channel quality indicator (CQI), feedback rate for each MS is determined exploiting the signaling of MAC layer automatic repeat request (ARQ) protocol, users application and mobility profile. More specifically, DCRA first derives the optimal average feedback window values based on the user velocity and service class for a target packet error rate. Using this information, DCRA can then allocate the CQI resource dynamically on frame-by-frame basis. Simulations comparing our approach to an exiting Doppler based mechanism show that DCRA reduces the feedback overhead significantly while maintaining the application QoS constraints.