CPN Modeling And Analysis Of Admission Control And Spectrum Handoff Strategy In Cognitive Radio Networks

After years of development, the wireless communication has become an indispensable part of people’s daily life and scientific research activities. With the sharp increase in demand for wireless spectrum, how to improve the spectral efficiency become the focus of research. Cognitive Radio (Cognitive Radio, CR) can realize dynamic spectrum management and make full use of the spectrum hole by Radio Resource Management (RRM), caused widespread concern of scholars both at home and abroad.Call Admission Control (CAC) and spectrum handoff is an important part of the radio resource management(RRM). This paper introduces a new modeling tools-Colored Petri Nets(CPN), modeling for admission control and handoff management. The model breaks through the Markov Markov Chain’s (MC) explicit limitation, which includes MC’s memory less property and proneness to state space explosion in evaluating CAC process. In view of this, the main contents are as follows:1) First, we develop an executable top-down hierarchical CPN model for Multi-Traffic CAC in Orthogonal Frequency Division Multiple Access (OFDMA) system. By theoretic analysis and CPN simulation, it is demonstrated that the CPN model is isomorphic to MC, assuming that each data stream follows the Poisson distribution and the corresponding arrival time interval is an exponential random variable. Moreover, we present four CAC schemes based on CPN model taking into account call-level and packet-level QoS. The simulation results show that CPN offers significant advantages over MC in modeling CAC strategies and evaluating their performances with less computational complexity in addition to its flexibility and adaptability to different scenarios.2) In Cognitive Radio Networks (CRN), spectrum mobility effectively improve the user’s QoS, and has become one of the important technologies to ensure the priority of primary users. According to the primary user’s behavior in the CR network, we study the probability of cognitive users switching N times in a service, and develop an executable top-down hierarchical CPN model. It breaks through MC explicit limitation, which includes MC’s memoryless property and proneness to state space explosion in evaluating handoff process. And the simulation results verify the correctness of the model.