基于排队论的认知无线网络从用户机会接入性能分析

In cognitive radio networks, the secondary users can communicate by access to the idle spectrums which are licensed to the primary users. Thereby, the spectrum efficiency can be improved. But the new arrived secondary users may not be able to use the spectrum to communicate immediately because the spectrum utilization of the primary users is random. This will result that the waiting delay rises before access to the spectrum opportunistically for the secondary users, and the excess waiting delay will lead to the spectrum access chance losing. So controlling the waiting time before access to the spectrum can help to improve the spectrum access probability for the secondary users. Accordingly, this paper proposes a Markov queuing model by considering the activity of both primary and secondary users in the cognitive radio network, and obtains the average waiting time of the secondary user in the steady state before access to the spectrum through the matrix-geometric solution theory. The final number results not only confirm the rationality of the analysis but also provide a reference to meet the secondary user's waiting delay before using the spectrum for the system.