Identifying the Guard Region for Cognitive Networks under Mutual Interference Constraints

Spectrum access opportunity is an important research topic in cognitive radio networks, which is both related to the transmission constraints from primary users and cognitive users. This paper analyses the relationship between deployment of cognitive network and mutual interference constraints from primary network to cognitive network and cognitive network itself. By utilizing the primary exclusive region scenario, the closed-form expression of the upper bound transmission probability for a cognitive user is obtained considering the interference constraints from the primary users and other cognitive users. Based on these results, we then derive the expected interference value at a primary receiver and obtain the more exact transmission range for the cognitive network compared to the past works. We also proposed an iteration process to evaluate the transmission probability and guard region width. The simulation results show that compared to the conservative guard region analysis, our analysis is more reasonable in terms of considering the mutual interference constraints and it guarantees more spatial access opportunities for cognitive users.