Date Added: Oct 2011
In this paper, the authors study the cross-layer resource allocation for the Secondary Users (SUs) supporting heterogeneous services in interference-limited spectrum sharing system. Two classes of SUs are considered: Delay-Tolerant SUs (DT-SUs) and Delay-Sensitive SUs (DS-SUs). With the queue theory, the delay requirements of DS-SUs are transformed into constant rate requirements. Unlike most previous works, this paper formulates the optimization problem by taking heterogeneous Quality of Service (QoS) of both Primary Users (PUs) and SUs into consideration. Moreover, based on the convex optimization theory, they propose the dual decomposition method in which the joint subcarrier assignment and power allocation are performed to achieve the optimal solution. To simplify the computation complexity, a suboptimal algorithm is proposed to decouple the optimization problem into two sub-problems.