Joint routing and channel assignment with switching interval maximization for cognitive radio networks

In multi-hop cognitive radio networks (CRNs), channel switching and rerouting for a secondary user´s (SU´s) traffic flow protect the transmission of the primary users (PUs); however, due to the extra overhead and delay, they deteriorate the quality of the SU´s transmission. In this paper, aiming to achieve a stable end-to-end delivery for a secondary flow, we study the problem of joint routing and channel assignment (JRCA), by exploiting the concept of expected switching interval (ESI). We first formulate the JRCA problem in a general setting without any constraint on the primary activity. Then, assuming Poisson arrival traffic for the PUs, we investigate the performance of the proposed scheme. Simulation results demonstrate that the proposed scheme enables a secondary flow on average to maintain a long end-to-end transmission time and thus reduces the risk of the flow being interrupted by the appearance of the PUs.