Joint resource allocation with statistical delay QoS guarantees for spectrum leasing CR networks

In this paper, we investigate the joint resource allocation policy for an orthogonal frequency division multiplexing (OFDM)-based cooperative cognitive radio network with statistical delay quality of service (QoS) guarantees. In the CR network, the spectrum leasing scheme operates in a situation where the primary users (PUs) lease part of its licensed spectrum to the secondary users (SUs) in exchange for the cooperation with SUs acting as decode-and-forward (DF) relays for PUs. Considering the statistical delay QoS requirement and to optimize the resource allocation of power and subcarrier, we formulate the problem of minimizing the secondary system's average power while achieving the effective capacity of both the primary system and secondary system. To reduce the computational complexity, an asymptotical algorithm and a suboptimal algorithm are presented in our paper. The corresponding resource allocation policies are derived based on the Lagrange dual approach. Numerical results show that the proposed policy performs better in saving power with QoS guarantees than other policies.