Interference Minimization Routing and Scheduling in Cognitive Radio Wireless Mesh Networks

Cognitive radio is a new communication paradigm that is able to observe, learn, optimize, and intelligently adapt to achieve optimal frequency band usage. Cognitive radio (CR)-based wireless mesh networks (WMNS) provide infrastructures for secondary users´ transmission, and it is necessary to develop techniques with low interference to primary users in such networks. In this paper, we propose an interference-minimization routing and scheduling algorithm for CR-WMNs. The flow control, route selection, time sharing, and opportunistic spectrum access are jointly formulated to minimize the aggregate interference to primary users. The optimization problem can be solved in a centralized way, and a distributed algorithm is also developed by adaptively modifying the individual link cost by the interference to the primary user and flow conditions. Simulation results show that the proposed scheme finds better routes in terms of interference to the primary users compared to the shortest path scheme, and the distributed solution shows near optimum compared with the centralized solution.