Analytical interference model in CSMA-based cognitive radio networks

In a typical cognitive radio network (CRN), secondary users can only access the channel when they do not harmfully interfere with the primary users. Therefore, an accurate estimation or prediction of interference from secondary users to primary users is essential. In this paper, we tackle the problem of interference estimation in a channel in presence of one PU and multiple SUs. We solve this problem from a novel perspective while taking media access control (MAC) into account. We assume that carrier sense multiple access (CSMA) standard is employed among secondary users, with which the secondary users are prohibited from transmitting once an active user is in their sensing ranges. As a result, the maximum number of simultaneously interfering secondary users is finite, typically ranging from 1 to 4. This considerably simplifies the interference model in cognitive radio networks. We present several cases with possible simultaneously interfering secondary users. Extensive simulations are conducted and results validate the effectiveness and accuracy of the proposed approach. We hope that this promising approach will shed light on the interference modeling in CRNs.