Average-sense joint rate and power allocation algorithm combined with admission control in cognitive radio networks

Abstract

In this paper, we investigate a dynamic spectrum sharing problem for centralized uplink cognitive radio networks using orthogonal frequency division multiple access. We formulate average-sense joint rate and power allocation as an optimization problem under quality of service and interference constraints, and suggest admission control to find a feasible solution to the optimization problem. To implement the resource allocation in average sense, we introduce a concept of using the conservative factors and depending on the outage and violation probabilities. Since estimating instantaneous channel gains is costly and requires high complexity, the proposed algorithm pursues a practical and implementation-friendly resource allocation. Simulation results reveal that the proposed average-sense resource allocation incurs a slight loss in system throughput over the instantaneous one, but it achieves the large-scale power adaptation with less sensitivity to variations in shadowing statistics. © 2009 IEEE.