On Spectrum Sensing Optimal Design in Spatial–Temporal Domain for Cognitive Radio Networks
Francesco Marino, Luigi Paura, Roberto Savoia · IEEE Transactions on Vehicular Technology · 2015
A key issue in spectrum sensing design is the optimization of sensing time, namely, the sensing time that maximizes the transmission throughput achievable by cognitive users (CUs), while limiting the interference against the primary user (PU). In a mobile network scenario, this issue becomes more challenging than that associated with the traditional case (i.e., stationary scenario), since in addition to the temporal PU activity, the spatial effects due to the relative mobility between the PUs and CUs have to be also taken into account. In fact, the mobility can deeply influence the percentage of discovered spectral opportunities (that is, the spectrum holes that the CUs can exploit) and also affect the transmission throughput achievable by the CU. To account for the PU temporal activity as well as the mobility effects, optimization is performed jointly in temporal and spatial domains, namely, by considering the impact of sensing accuracy on the actual transmission throughput achievable by a CU. More specifically, a theoretical analysis is carried out for an arbitrary network mobility model to prove the existence of a single optimal sensing time that maximizes the mobility-aware sensing-enabled throughput achievable by a CU. Then, the theoretical analysis is validated through extensive simulations carried out by considering two widely adopted mobility models. The theoretical analysis together with the numerical analysis provide the guidelines for the spectrum sensing design, by showing how the optimal sensing time depends on the parameters characterizing the adopted mobility model, the PU temporal activity, and radio environments.