Radio Resource Management for Fast Fading Environments

Adaptive resource allocation based on perfect Channel State Information (CSI) can significantly improve the performance of Orthogonal Frequency Division Multiple Access (OFDMA) systems. However, in real systems, accurate CSI is impossible because of noisy channel estimates, channel feedback delays, and processing delays. Therefore, only imperfect CSI can be used for resource allocation purposes. In this paper, we minimize the impact of errors caused by imperfect CSI and evaluate the significance of periodic CSI feedback in a fast fading environment. In a fast fading environment, periodic CSI feedback requires a high overhead load; and the uplink resources reserved for feedback purposes are limited. Thus, we present a strategy that optimizes the usage of those uplink resources. Simulation results show that this strategy leads to a higher overall fairness and system throughput.