Research On Cooperative NOMA Communication Assisted By Smart Reflective Surfac

Currently,the 5th Generation Mobile Networks(5G)application scenario has expanded from the mobile Internet to the Internet of Things,achieving deep integration with vertical industries and opening up a new era of industrial Internet.Driven by the challenges of rapidly expanding network scale,difficult to utilize massive data volumes,and increasing productivity,mobile communication networks are facing demands for massive data connections,ultra-low latency and ultra-high frequency spectrum efficiency,and research on potential enabling technologies is imminent.In this context,technologies such as Intelligent Reflecting Surface(IRS)and Non-Orthogonal Multiple Access(NOMA)have emerged to perform well in terms of system throughput,energy efficiency and extended system access range.In this paper,we study IRS-NOMA,IRS-assisted Two-Way(TW)NOMA and active IRS(AIRS)assisted TW-NOMA communication networks under nonideal hardware conditions,and analyse the effects of relevant parameters such as the number of IRS elements,path loss and residual interference values on the performance of network outage probability,traversal rate,system throughput and energy efficiency.With the help of tools such as the central limit theorem and the Laguerre class approximation theory,an optimisation scheme for network performance is designed to improve spectrum resource utilisation,user communication quality of service and diversity gain,the main work of this paper is as follows:(1)To address the problem of received signal distortion caused by hardware impairments(HI)of the system transceiver,an IRS-NOMA communication network performance analysis scheme is proposed for the co-existence of direct and reflected links under non-ideal hardware conditions.The performance of the IRS-NOMA-HI network in the Rice channel is analysed with correct demodulation by the Successive Interference Cancellation(SIC)mechanism.Closed-form solution expressions and asymptotic expressions for the outage probability are derived based on the Laguerre class approximation theory to obtain the diversity order at high Signal to Noise Ratio(SNR).At the same time,the system throughput in delay-limited transmit mode is investigated,and the effects of parameters such as the road loss factor and HI values on the IRS-NOMA-HI communication network are analysed to improve the performance of the NOMA network under the influence of hardware impairment.The simulation results show that: 1)the IRS-NOMA-HI network outperforms the IRS-OMA-HI in terms of outage performance and system throughput when the system serves multiple users at the same time;2)the HI value has a large impact on the performance of the IRS-NOMA-HI network,and the HI should be accurately modelled when evaluating the network performance.(2)To address the problems of small coverage area and limitations of equipment in traditional NOMA networks,a research proposal on the performance of multi-user IRS assisted TW-NOMA communication networks is proposed.Based on the central limit theorem,expressions for the outage probability and ergodic rate of the near-end and far-end users are derived,and the diversity order and high SNR slope of the users are obtained.Also,the system throughput and energy efficiency of this network are analysed under two transmission modes,delay-limited and delay-tolerant.The simulation results show that: 1)the IRS-TW-NOMA network has a diversity order of 0 in the non-ideal SIC case,and the interruption probability and ergodic rate have error leveling and throughput upper bounds at high SNR,respectively;2)compared to both the IRS-TW-OMA and TWR-OMA models,the outage performance,ergodic performance,system throughput and energy.Compared with the IRS-TW-OMA and TWR-OMA models,the IRS-TW-NOMA network has better outage performance,ergodic performance,system throughput and energy efficiency.(3)To address the problems of multiplicative fading in the conventional IRS phase shift matrix,the performance of TW-NOMA communication networks assisted by AIRS is investigated to improve the received signal quality and reduce the power consumption.Ergodic rate closed-form solution expressions and asymptotic expressions are derived for users in the ideal SIC and non-ideal SIC cases to obtain high SNR slopes for users;at the same time,system throughput in delay-tolerant transmit mode is derived to analyse the impact of each parameter on system performance.The numerical simulation results show that: 1)the ergodic rate and system throughput of the AIRS-TW-NOMA network are better than those of AIRS-TW-OMA and IRS-TW-NOMA;2)the ergodic rate of the AIRS-TWNOMA network becomes larger and larger as the number of AIRS elements increases.This paper investigates the network performance of IRS-NOMA-HI,IRS-TW-NOMA and AIRS-TW-NOMA in the context of wireless communication networks,aiming to alleviate the challenges of spectrum resource scarcity and full-coverage implementation,and to provide theoretical support for the optimal design of next-generation mobile communication systems.