Optimal Cluster Power for Joint Spectrum Sensing and Secondary Data Transmission in Cognitive Radio Networks

This paper considers the problem of joint spectrum sensing and secondary data transmission in the relay-assisted cognitive radio networks. An optimization problem is formulated that searches for the cluster-wise relay selection and consequent power allocation with an objective to maximize the sum throughput of the secondary network under the constraints of the interference power limit and the probability of primary user's (PU) signal detection. Fuzzy c-means clustering algorithm is applied to associate a set of secondary users (SUs) to form a cluster at the source as well as in destination end followed by their link establishment via a particular relay. Closed form expression for the optimal cluster power allocation is derived and the performance of the proposed system is investigated in terms of secondary network throughput and sum cluster power for SU data transmission. A large set of simulation results show that a gain similar to 24.37% and similar to 36.03% in SU throughput are achieved for the proposed scheme when compared to the existing works.