Introduction to algorithms
Proceedings of first ACM/IEEE international workshop on Mobility in the evolving internet architecture
Dynamic Spectrum Access with QoS and Interference Temperature Constraints
IEEE Transactions on Mobile Computing
Cognitive radio network architecture: part I -- general structure
Proceedings of the 2nd international conference on Ubiquitous information management and communication
IEEE Transactions on Information Theory
Zero-error network coding for acyclic networks
IEEE Transactions on Information Theory
A Network Coding Approach to Cooperative Diversity
IEEE Transactions on Information Theory
Outage probability analysis of cognitive transmissions: impact of spectrum sensing overhead
IEEE Transactions on Wireless Communications
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After successful dynamic spectrum access, cognitive radio (CR) must be able to relay the message/packets to the destination node by utilizing existing primary system(s) (PS) and/or cooperative/cognitive radio nodes in the cognitive radio network. In this paper, we pioneer the exploration of the fundamental behaviors of interference between CRs and PS in such a relay network via network coding. Interference on PS's network capacity is shown to be unavoidable and unbounded in the one-hop relay network. Extending to the tandem structure, interference is unbounded but avoidable by appropriate constraints. In cooperative relay network, interference is bounded and avoidable. Moreover, parallel cooperative relay network can accommodate more CR transmission pairs. Such an analysis can be generalized to arbitrary networks. We derive that interference is avoidable when at least one route from CR's source to the sink bypasses the bottlenecks of PS. Then under the constraint of no interference to PS, we derive CR's maximum network capacity in such a network. Link allocation to achieve the maximum network capacity can be formulated and solved as a linear programming problem. Consequently, given any network topology, we can determine whether CR's interference is avoidable, and maximize CR's network capacity without interfering PS's network capacity. Simulation results on randomly generated network topologies show that CR's network capacity achieves on average 1.3 times of PS's network capacity with interference avoidance constraint, and demonstrates spectrum efficiency at networking throughput and high availability.