Resource Allocation in Opportunistic Cooperative Cognitive Radio Network with PU's Statistical Delay QoS Provisioning

Cooperation in cognitive radio network (CRN) can improve the performance of both primary user (PU) and secondary user (SU) while guaranteeing PU's quality-of-service (QoS). In this paper, we propose a joint time slot and power allocation policy for an opportunistic cooperative cognitive radio network (OCCRN) where PU and SU can opportunistically cooperate with each other to improve the system performance. The proposed scheme aims at two-fold benefits that can improve SU's throughput and reduce PU's power consumption while protecting PU's statistical delay QoS provisioning. According to the theory of effective capacity, the statistical delay QoS requirement can be converted into the requirement of the effective capacity. Thus, we formulated a multi-objective optimization problem maximizing SU's effective capacity and minimizing PU's average power consumption subject to PU's statistical delay requirement and SU's power budget. With the weighting method, the multi-objective optimization problem is transformed into a single-objective optimization problem which is verified as convex and then solved by the Lagrangian dual method. Utilizing the proposed resource allocation policy, the OCCRN first chooses the transmission mode for each frame and dynamically adjusts the time slot and transmission power of both PU and SU to optimize the two-fold benefits under given constraints. Simulation results demonstrate the trade-off between SU's throughput and PU's power consumption under diverse statistical delay QoS requirements, illustrating how PU and SU cooperate with each other to achieve optimal performance.