Interference Modelling for Heterogeneous Cognitive Radio Networks

Cognitive radio (CR) network can solve the problem of spectrum shortage. In the CR network, primary user and secondary users share spectrum resources, and the interference of secondary users to primary user is the key research issue. Therefore, interference modeling came into being, which is helpful to the reasonable layout planning of the actual CR network. However, the existing interference modeling models have high computational complexity, and some of them cannot get closed expression forms. A multi-tier model is presented in this paper to describe the distribution of users in CR networks. In this model, the main receiver is the center of each ring. The signal-to-interference power ratio (SIR) and the outage probability at the primary receiver are derived by low-computational. The specific method is to quantify the secondary users space area by polar coordinates. Through simulation verifies the validity of the SIR and the outage probability. In addition, the influence of important parameters of CR network is discussed through simulation.