Research On Non-orthogonal Multiple Access Technology Based On Simultaneous Wireless Information And Power Transfer

With the rapid development of mobile communication technology,the problem of energy shortage is becoming increasingly serious.To better cater to the fifth generation mobile communication system(5G),simultaneous wireless information and power transfer(SWIPT)is considered an effective way to solve this problem due to the fact that it can provide users with more stable and controllable power.SWIPT can provide energy for remote mountainous areas or inconveniently mobile wireless devices,thereby extending the life of the network,such as,Internet of Things(Io T),and vehicle-toeverything(V2X).In the practical communication systems,the incomplete matching of radio frequency(RF)hardware,the imperfection of manufacturing process and the force majeure factors,such as geographical environment,the RF hardware will always be affected by phase noise,in-phase and quadrature-phase imbalance(IQI),nonlinear power amplification,etc.Although these factors can be corrected by some compensation algorithms,it is also an intractable problem to eliminate the effects completely.In this thesis,the performance of non-orthogonal multiple access(NOMA)systems is investigated.In addition,SWIPT,residual hardware impairments(RHIs),multiple relays and channel estimation errors(CEEs)are also taken into account.The main contributions are summarized as follows:First,the performance of full-duplex(FD)cooperative NOMA relaying systems in the presence of IQI and imperfect successive interference cancellation(SIC)is analyzed and evaluated.In particular,by considering two classes of users located far from and near to the information source,closed-form exact and analytical approximate expressions for the outage probability and ergodic sum rate,respectively,are derived.The accuracy of the analytical approach is verified by computer simulations which have shown that for both cooperative NOMA and equivalent OMA systems IQI has a deleterious effect on their outage probability and ergodic sum rate performance in moderate and high SNR regions and the outage probability of cooperative NOMA is always slightly lower than that of the traditional OMA.Additionally,comparisons with equivalent half-duplex(HD)cooperative NOMA schemes have revealed that for the far user the FD cooperative NOMA scheme is less sensitive to imperfect SIC.Next,the joint impact of RHIs and CEEs on the cooperative SWIPT NOMA multirelay networks with the aid of a power beacon.To evaluate the performance of the considered network,the exact and asymptotic expressions of the outage probability for NOMA users are derived.To gain deeper insights,the diversity orders and system throughput are also discussed.Numerous results show that there exist error floors of the outage probability caused by CEEs;the direct links can improve the system performance and there exists an optimal power allocation factor to maximize the outage performance.Finally,the effects of RHIs,CEEs and imperfect SIC on the cooperative SWIPT NOMA system is investigated.The exact expressions for outage probability and ergodic sum rate are derived in closed-form.In addition,the asymptotic outage analyses in the high SNR regime are carried out.The results show that the outage probability exists an error floor due to the existence of CEEs and compared with RHIs,CEEs have a more serious impact on the system outage performance.