Performance Research Of The Dynamic Spectrum Allocation Schemes With Possible Transmission Interruption Based On Queueing Game

For the purpose of improving the wireless spectrums utilization, alleviating the pressure for the shortage of spectrum resources, and coping with a large demand for spectrums caused by the rapid developments of wireless network applications. The dynamic spectrum allocation schemes are introduced by cognitive radio networks. In this paper, considering the response performance of the cognitive users, the interrupted cognitive user packets are supposed to leave the system. Then continuous-time queueing models with possible transmission interruption are established. Based on the queueing theory and game theory, the system performances of the dynamic spectrum allocation schemes in cognitive radio networks are evaluated with the unobservable and observable buffer state of the cognitive user packets respectively.First of all, from the view of the unobservable buffer state of the cognitive user packets, a continuous-time queueing model with infinite buffer and possible transmission interruptions is established. Based on the dynamic spectrum allocation schemes in cognitive radio networks, using the Laplace transform method, the expressions of the average response time, the system throughput and the spectrum switch rate are derived. With the numerical experiments, the system performance is analyzed.Secondly, under the observable buffer state, individual average benefit function of the cognitive user packets and the social benefit function of the spectrum are developed. The arrival rate of the cognitive user packets under the game equilibrium state is proved be greater than that under the maximum social benefit of the spectrum. By proposing spectrum access fee charging for the cognitive user packets, the social benefit of the spectrum with the dynamic spectrum allocation schemes is maximized.Thirdly, from the view of the observable buffer state of the cognitive user packets, by constructing an individual average benefit function, the buffer threshold of the cognitive user packets is given in the game equilibrium state. Considering the dynamic characteristics of the spectrum allocation schemes in cognitive radio networks, paralleling to the unobservable buffer state situation, a continuous-time queueing model with finite buffer and possible transmission interruptions is built. Based on the steady-state equations, performance measure expressions for the cognitive user packets are derived. Combining the numerical experiments, the influences of the arrival rate and the transmission rate for the cognitive user packets on the system performance are studied.Finally, under the unobservable buffer state, in cognitive radio networks, the social benefit function of the spectrum is constructed for the dynamic spectrum allocation schemes. Comparing the game equilibrium state of the cognitive user packets with the maximum social benefit state of the spectrum, we reveal that the buffer threshold of the cognitive user packets under the game equilibrium state is higher than that under the maximum social benefit of the spectrum. In order to get consistency between the game equilibrium and the maximum social benefit of the spectrum, spectrum access fee charging for the cognitive user packets is proposed.