Resource allocation for OFDMA systems with guaranteed outage probabilities

In this paper, we propose a resource allocation scheme to maximize users' minimum rate with a guaranteed outage probability for Orthogonal Frequency Division Multiple Access (OFDMA) systems with imperfect CSI. To avoid the system degradation caused by the noisy and outdated CSI, we consider the minimum mean square error (MMSE) channel prediction scheme at the base station (BS). We derive the parameter, namely, the equivalent channel gain, which is determined by the requirement of the outage probability and the channel estimates at the BS. With this parameter, we can maximizes users' minimum rates under a transmit power constraint and given outage probabilities. To reduce the complexity, we propose a two-step suboptimal approach that separately performs subcarrier and power allocation. Simulation results show that the performance of the resource allocation scheme is robust against channel estimation errors and feedback delays in OFDMA systems.