Analysis On Opportunistic Spectrum Access In Cognitive-based Networks

Cognitive radio is widely regarded as one of the most promising technologies for future wireless communications. Cognitive radio is the enabling technology for supporting opportunistic spectrum access: the policy that addresses the spectrum scarcity problem.Opportunistic spectrum access has been proposed as a policy to allow the radio spectrum to be more efficiently used. In this paper, our main objective is to analyze the opportunistic spectrum access in cognitive radio network and cognitive femtocell network.In the cognitive radio network, we use the preemptive resume priority M/M/1 queuing model to model the users' access procedure, and analyze the transmission delay of priority-based secondary users. The second users are with different priority levels. The secondary users with the high priority level can access a channel in preference to the low priority level secondary users when the channel is available. The queuing model can effectively guarantee the quality of service of the high priority level secondary users and reduce the overall transmission delay of the interrupted secondary users.In the cognitive femtocell network, we use the four dimensions continuous time Markov chain to model the users' access procedure. We analyze the grade of service of different kinds of users and the spectrum utilization. Moreover, through the Markov chain, we investigate both the non-hopping and hopping modes, respectively. We study the grade of service of users and effective spectrum utilization in different modes.In this paper, we analyze the opportunistic spectrum access in cognitive radio network and cognitive femtocell network. Through the preemptive resume priority M/M/1 queuing model and the four dimensions continuous time Markov chain model, we investigate the users' access procedure. Some simulations are processed in MATLAB, and simulation results verify the correctness of the theory.