Primary social behavior aware routing and scheduling for Cognitive Radio Networks

As an objective reality, the social behavior pattern of Primary Users (PUs) has significant impacts on the design and management of the secondary network. However, most of the existing works overlook this fact by simplifying the spectrum whitespace assumption. In this paper, we study the joint routing and time-domain scheduling problem for Cognitive Radio Networks (CRNs) by considering the social behaviors of PUs. Our main contributions consist of four aspects. First, we analyze the social pattern of PUs based on two practical data traces. According to the obtained social pattern, the available spectrum whitespace is derived for SUs. Subsequently, in terms of previous analysis, we propose a centralized joint routing and time-domain scheduling framework with global provable ε-optimality (ε ∊ [0,1]) by employing the branch-and-bound technique, where ε indicates the expected closeness of our solution to the optimum solution. The solution of this centralized algorithm can serve as a theoretical benchmark for developing future routing and scheduling algorithms for CRNs. Third, we design a distributed primary behavior-aware routing and scheduling algorithm with local performance guarantee, where the routing and scheduling fairness, the available bandwidth, the potential interference, etc. are taken into account. Finally, simulation results confirm our assertion that primary behaviors have significant impacts on the spectrum whitespace, and demonstrate that primary-behavior-aware joint routing and scheduling design can utilize spectrum whitespace efficiently.