Abstract: Cognitive radio (CR) is a technology used for wireless networks to solve the problem of spectrum underutilization. It can be achieve by opportunistically exploiting portions of the spectrum temporarily by vacating licensed primary users. In this paper, we make a survey of traditional and recent routing protocols used for successful multimedia routing in Cognitive Radio Networks (CRNs). First we focus on how CRNs are different from other wireless networks and then list out the number of challenges and main issues of routing in Cognitive Radio Networks (CRNs). We then present different routing protocols that are specially designed for CRNs. The main aim in designing the routing protocols for the cognitive radio networks is the combine design of routing and spectrum management. Works on such issues have just started and are still in a progressing stage.

Keywords: CRSN, multimedia routing, routing protocol, spectrum, cross layer routing.