Outage Throughput Maximization for OFDMA Systems with Feedback Channel Capacity Constraints

We investigate the maximum outage throughput for Orthogonal Frequency Division Multiple Access (OFDMA) systems in the presence of feedback channel capacity constraints. We attempt to establish an information-theoretic lower bound on the capacity of feedback channel and build the corresponding test channel that achieves this lower bound. Based on the derived test channel, we formulate the outage throughput maximization problem with the quantized CSI. Since the optimal solutions require an exponential time complexity, we propose a low complexity suboptimal approach that separately performs subcarrier and power allocation. Numerical results show that the proposed suboptimal approach can achieve a near optimal performance, and the outage throughput with a limited feedback of CSI can be close to that with perfect CSI by exploiting correlation properties of downlink CSI for quantization.