Sensing matrix setting schemes for cognitive networks and their performance analysis

Powerful spectrum decision schemes enable cognitive radios (CRs) to find transmission opportunities in spectral resources allocated exclusively to the primary users. One of the key effecting factors on the CR network throughput is the spectrum sensing sequence used by each secondary user (SU). In this study, SUs´ throughput maximisation through finding an appropriate sensing matrix (SM) is investigated. First, the average throughput of the CR network is evaluated for a given SM. Then, an optimisation problem based on the maximisation of the network throughput is formulated in order to find the optimal SM. As the optimum solution is very complicated, three novel suboptimal solutions are proposed for various cases including perfect and non-perfect sensing. Despite having less computational complexities as well as lower consumed energies, the proposed solutions perform quite well compared to the optimum solution. The structure and performance of the proposed SM setting schemes are discussed in detail and a set of illustrative numerical results is presented to validate their efficiencies.