Performance Research For Swipt Communication System Based On Ambient Backscatter

With the development of the Internet of Things and wireless communication technology,a large number of wireless devices will be deployed in wireless communication networks to realize communication and data processing between people,people and things,and things and things.Massive connections require a lot of energy and spectrum resource.Ambient Backscatter(AB)use the existing wireless signal in the environment as a carrier signal to scatter its own signal by the tag without additional spectrum resources and energy.The advantage of AB technology is low energy consumption.At the same time,Simultaneous Wireless Information and Power Transfer(SWIPT)collects energy from radio frequency signals for usage,which can effectively relieve the energy supply pressure of the system.Therefore,combining AB with SWIPT technology can greatly reduce the energy consumption of communication systems.In addition,Non-Orthogonal Multiple Access(NOMA)can effectively improve spectral efficiency.Thus,it is widely used in SWIPT systems.This thesis applies cooperative relay and NOMA technologies in AB-based SWIPT communication systems to improve system reliability and effectiveness.The main work contents are as follows:(1)For the AB-based SWIPT cooperative relay system,using the ambient backscatter technology assists the relay node communicates with the secondary node.This passage evaluates the outage performance of the relay system(primary system)and the ambient backscatter system(secondary system).And derives the approximate outage probability expressions in closed form.In addition,the influence of different system parameters on system performance is analyzed,and the correctness of the theoretical derivation is verified by simulation.In order to reflect the performance gain brought by AB,this passage compares the SWIPT cooperative relay network with AB and without AB.And the results show that the AB-based SWIPT cooperative relay system has significantly improved the system throughput and energy efficiency.(2)For the SWIPT-NOMA system based on AB,due to the less power allocated in the near user of the NOMA system.By adding a backscattering link to assist the near user in communication.The closed-form expressions of the outage probability of the far user and near user is derived.We analyze the influence of different parameters on the system outage performance,and the correctness of the theoretical derivation is verified by simulation experiments.On the other hand,by comparing the performance of AB-SWIPT-NOMA system;SWIPT-NOMA system and SWIPT-OMA system.The results show that AB-SWIPT-NOMA system get the best performance.Thus,NOMA and ambient backscatter technology can effectively improve communication reliability the energy efficiency of the system.