Research On Outage Probability Of Cognitive Relay Network Based On SWIPT

Cognitive radio(CR)technology can effectively solve the problem of spectrum shortage and low frequency utilization,and in the underlay spectrum sharing mode,the secondary user can directly access the authorized spectrum when the transmitting power of the secondary user is within the given interference power of the primary user.Collaborative communication technology can provide a high reliability transmission mode and a high connectivity network architecture for wireless networks without reducing the system power.In addition,Wireless Power-Portable Communications(SWIPT)technology can be used to transfer both power and information.In this paper,SWIPT technology is applied to the cognitive relay network to further improve the reliability and energy efficiency of the system.The research work of this paper mainly includes the following two points:(1)Aiming at the cognitive two-hops relay network model based on SWIPT,this paper analyzes the outage probability of the secondary user in the underlay spectrum sharing mode,and deduces the expression of the secondary user outage probability under the constraints of the maximum transmitting power and the primary user interference threshold.The simulation results show that the performance of the cognitive relay network based on SWIPT is slightly worse than the performance of the traditional cognitive relay network,but because SWIPT technology can simultaneously carry out energy and information transmission,the energy efficiency is better than the traditional network,especially suitable for the complex environment which is difficult to replace the power supply.(2)In order to improve the transmission performance of cognitive relay network based on SWIPT,a cognitive relay network with direct links is considered in this paper,and the analytical formula of outage probability for the next user in underlay spectrum sharing mode is derived.The simulation results show that the outage performance of the system is affected by the distance between the secondary user transmitter and the secondary user receiver and the location of the relay node.Compared with the two-hop relay network,the network with direct link can effectively improve the reliability of the communication system.