We consider a joint optimization of sensing parameter and power allocation for an energy-efficient cognitive radio network (CRN) in which the primary user (PU) is protected. The optimization problem to maximize the energy efficiency of CRN is formulated as a function of two variables, which are sensing time and transmit power, subject to the average interference power to the PU and the target detection probability. During the optimizing process, the quality of service parameter (the minimum rate acceptable to secondary users (SUs)) has also been taken into consideration. The optimal solutions are analyzed and an algorithm combined with fractional programming that maximizes the energy efficiency for CRN is presented. Numerical results show that the performance improvement is achieved by the joint optimization of sensing time and power allocation.

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In a cognitive radio network (CRN), when the secondary users (SUs) are battery-powered devices, the concept of energy-efficient design is very important. The sensing time and the number of cooperative SUs in the cooperative spectrum sensing could greatly affect energy consumption and throughput of the system. In this paper, we propose an energy utility function by formulating the achievable data rate of a cooperative CRN in terms of the energy consumption by the CRN. The maximization of the energy utility function is obtained by jointly designing the sensing time, sensing threshold, and number of cooperative SUs with the constraint of sufficient protection for primary user (PU). Numerical results show that the CRN can achieve almost the maximum achievable data rate with significant energy saving through the joint optimization.

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In a cognitive radio network (CRN), cooperative spectrum sensing could increase the accuracy of the sensing results by mitigating the effect of multipath and shadowing. However, cooperation also introduces additional reporting time corresponding to the number of cooperative secondary users (SUs), which may decrease the throughput of the CRN. In this paper, a problem of jointly optimizing the sensing time, sensing threshold and numbers of cooperative SUs for each channel in multi-channel CRN is formulated to maximize the average achievable throughput of CRN while guaranteeing the priority of the primary user (PU) and the spectrum opportunity for the SUs. Numerical results show that the redundant SUs involved in the spectrum sensing may reduce average throughput, and an improvement in the throughput of the CRN is achieved through the joint optimization.978-1-4799-0308-5/13/$31.00