Performance Assessment And Optimization For Energy Saving Strategy In Wireless Regional Area Network

Wireless Regional Area Network(WRAN)based on IEEE 802.22 standard adopts centralized network architecture and is currently one of the most typical cognitive radio networks.It is an effective method to realize the green communication to reduce the energy consumption of the communication networks with the constraint o f spectrum resource utilization.Based on the WRAN environment and the perfect sensing results,we research the performance and optimization of periodic sleep mechanism in the discrete time domain.Firstly,in order to reduce the energy consumption of the system,we introduce the periodic sleep mechanism in the WRAN and propose an Energy Saving Strategy with Single Rate Transmission(SRT-ESS).Considering digital nature of communication,we build a discrete-time priority queuing model under unlimited cache and multiple-vacation.Considering the demand real-time transmission of some secondary user packets,we build a discrete-time priority queuing model under limited cache and multiple-vacation.With the help of the Matrix-Geometric Solution method,we analyze the steady state of the system model.Secondly,based on the analysis of steady state of the SRT-ESS,we derive the average latency and the blocking rate of secondary user packets,as well as the energy saving ratio of system.In addition,system experiments are carried out to depict the influence of different system parameters(sleep parameter,cache capacity,et al.)on the performance of the system and to verify the effectiveness of the SRT-ESS.Thirdly,in order to balance energy saving of the system and the response performance of the secondary user packets,we introduce a working sleep mechanism.An Energy Saving Strategy with Dual Rate(DRT-ESS)is proposed.Combining the multiple-vacation queue and priority-queue,using the quasi-birth-death process and the matrix-geometric solution method,we assess the average latency and the forced termination probability of secondary user packets,as well as the energy saving ratio and the channel utilization of system.In addition,system experiments are carried out to depict the influence of different system parameters on the performance of the system and to verify the effectiveness of the DRT-ESS.Lastly,for the secondary users,we consider the behaviors opportunity to access channel.Based on the revenue-expenditure structure,a profit function is built,and then the Nash equilibrium behavior and the socially optimal behavior are investigated.In order to achieve optimum society,a reasonable channel access fee is formulated.In view of the compromise among the average latency and the blocking rate of secondary user packets,as well as the energy saving ratio of system,we give the optimization scheme of the capacity spectrum through setting up the system cost function.