An interference model for heterogeneous cognitive radio networks

This paper proposes a multiple-ring model to characterize the distribution of heterogeneous cognitive radio (CR) users with a primary receiver locating at the center of the rings. The aggregate interference received at the primary receivers from heterogeneous CR users is modeled by deriving its probability density function (PDF), where the method of characteristic function is employed. Moreover, log-normal approximation is applied on the derived PDFs to obtain closed-form expressions. Numerical simulation is carried out to verify the correctness of the derived PDFs and the accuracy of the corresponding approximation. Furthermore, the impact of various deployment parameters of the heterogeneous CR users on the aggregate interference is systematically evaluated via simulations as well.