LAUSR

In this paper, we study the mutual interference in the context of a hybrid interweave-underlay cognitive communication where transmission constraints from both primary and secondary networks are considered. The transmission of a secondary user in such a network is generally constrained by the primary network so as to avoid harmful interference to the primary receiver. In addition, we consider a constraint from the secondary network to avoid harmful interference to other secondary receivers. To this end, the transmission probability of a secondary user is derived from the joint density function of the distances from secondary users to the primary receiver and that of between secondary users. Inspired by inherent benefits of an interweave-underlay hybrid approach, we further consider the impact of spectrum sensing on the transmission probability of the secondary users. The derived expression allows us to analyze the interdependency of protection margins that may be enforced by the primary and secondary networks. Relying on this analysis, we then derive closed-form expressions for expected aggregated interference to the primary and secondary receivers. Furthermore, we propose a power control approach enabled by an in-band signaling link to minimize the mutual interference to the receivers in the network. In order to show the effectiveness of the proposed interference modeling, we simulate a cognitive network with such constraints from both networks and evaluate the aggregated interference experienced by the receivers. Finally, we validate our interference model by comparing theoretical and simulated aggregated interference experienced by the receivers.