Equilibrium Analysis For The Dynamic Spectrum Allocation Strategy In CRN

It is predicted that the 5G networks(The 5th Generation Networks) will enter people’s daily lives. The limited spectrum resources will be the key factor to affect the development of the radio technology. The dynamic spectrum allocation strategy with cognitive function brings a novel idea to improve the utilization of wireless resource. By employing discrete time queue theory and game theory, in this paper, we investigate the dynamic spectrum allocation strategy and analyze the system performance in cognitive radio networks.Firstly, in order to trade off the throughput and the average delay of secondary users, a novel PF-DSAS(Dynamic Spectrum Allocation Strategy with Probabilistic Feedback) is proposed. Taking into consideration the imperfect sensing results of SU and the preemptive priority of primary user packets, a kind of priority queueing model is established, in which two classes of users may interfere with each other. By employing the method of matrix-geometric solution, the expressions for some important performance measures are derived and the tradeoff between the system measures is verified.Sencondly, in order to decrease the average delay of SU packets, an ATPF-DSAS(Dynamic Spectrum Allocation Strategy with Probabilistic Feedback and Admission Threshold) is proposed. Based on the unobservable scenario, a kind of priority queueing model is constructed. By using an embedded Markov chain, the one step transition probability matrix is given, the system measures are derived and the influence of the system parameters to ATPF-DSAS is revealed.Thirdly, considering the possible impatience of SU packets queueing in the buffer, an IB-DSAS(Dynamic Spectrum Allocation Strategy with Impatience Behavior) is proposed. Based on the partially observable scenario, taking into account the influence of the channel states to US packet, a kind of priority queueing model with reneging is constructed. By analyzing the stationary probability distribution of the spectrum access mechanism, the expressions of the system performance are derived and the effection of the system parameters to IB-DSAS is revealed.Lastly, for different strategies proposed in this paper, the change trends of the net benefit for an SU packet and the social welfare along with the arrival rate of SU packets are analyzed. The phenomenon is revealed that there will be more SU packets entry into the buffer under individual optimization compared to social optimization. By formulating price policy, a reasonable admission price of SU packets is provided and the social optimization is realized.