Efficient and Fair Resource Allocation Scheme for Cognitive Satellite-Terrestrial Networks

In this paper, we consider the resource allocation problem in uplink cognitive satellite-terrestrial networks, where the cognitive satellite users reuse the frequency band of terrestrial cellular networks. In this scenario, the joint radio resource allocation strategy has to be reasonably designed to satisfy the interference constraint required by the incumbent terrestrial network (ITN). We formulate the optimization model of joint resource allocation with the perspective of efficiency and fairness, where the interference constraint is defined as the maximum tolerable interference outage probability of the ITN. Then, we simplify the proposed optimization problem into a tractable convex optimization form by some necessary mathematical simplification, wherein the simplification of the probability constraint takes the outdated channel state information into account. By analyzing the conditions of the optimal solution for the joint resource allocation problem in detailed, we derive the closed-form expression for both power allocation and subchannel allocation. Besides, we design an iterative algorithm for the joint resource allocation based on these closed-form solutions. Finally, some supporting results are given to verify the correctness and efficiency of the proposed algorithm.