Priority Based Routing and Link Scheduling for Cognitive Radio Networks

To address the challenges caused by the time-varying rate requirement for multimedia communication sessions, we propose a Priority Based Routing and link Scheduling (PBRS) scheme for multi-hop cognitive radio networks. The objective is to minimize disruption to communication sessions due to channel switching as well as to minimize network resource consumption for multimedia applications based on a prioritized routing and resource allocation scheme. PBRS includes a priority based optimization formulation and an efficient algorithm to solve the problem. The main idea is to allocate the available resource to different types of services with their Quality of Experience (QoE) expectation as well as maintain a priority service queue. Services with higher priority such video conference with cognitive radio expects a lower latency during the communication, whereas services with lower priority such as file transferring could tolerate more interruptions. Based on the different QoE requirements of services, PBRS will decide whether or not to change the routing and link scheduling. If a session has a higher priority than the others, PBRS will maintain its routes, channels, and links to the next timeslot as long as the total white space resource is enough to support all sessions. This eliminates unnecessary channel switching due to rescheduling. Simulation results demonstrate that PBRS effectively reduces channel switching and hence reduce disruption to communication sessions.