Research On Ultra-reliable MU-MIMO Technology Under ?-? Shadowed Fading

Improving the reliability of Internet of Things(Io T)applications has been a research hotspot in recent years.Most Io T applications with the characteristics of deep fading,short packets,and imperfect channel state information(CSI),it is pretty difficult to improve the reliability of Io T applications under the adverse effects of these characteristics.In order to achieve ultra-reliable communications in Io T applications with limited bandwidth,latency and numerous users,multi-user multiple-input and multiple-output(MU-MIMO)technology has also received wide attention.However,most of the existing researches are based on classic fast fading models such as Rayleigh and Rician,which cannot fit the most practical fast fading situations well.In addition,the classical Shannon information theory based on the assumption of infinite block length and random coding schemes is difficult to apply to short packets transmission.Therefore,the application of MU-MIMO technology in Io T still faces two problems that need to be solved.One is how to improve the fitness of model under the influence of fast fading with diversity and uncertainty,and the other is how to analyze and improve the reliability of short packets transmission.To this end,this thesis carries out research on the ultra-reliable MU-MIMO technology based on the unified fading model,including:1.In the uplink MU-MIMO system,based on the emerging ?-? shadowed fading,under perfect and imperfect CSI,the post-processing signal-to-noise ratio(SNR)and its probability density function(PDF)expressions of the received signal after the maximumratio combining detection are re-derived.2.Based on the above research,combined with the emerging non-orthogonal multiple access(NOMA)method,two users are matched into a group.In the uplink MU-MIMO system based on NOMA,after maximum-ratio combining,zero-forcing,and minimum mean-square error detection,as well as detection based on serial interference cancellation technology,the post-processing SNR and its PDF expression of the received signal are derived respectively.3.Based on the finite block length information theory,the error probability under different detection methods is calculated and used as the reliability evaluation index.Under the condition that bandwidth and latency are both limited,the reliability can be effectively improved by reasonably adjusting the system configuration such as the number of base station antennas,user transmitted power,resource allocation,and the access scheme.The simulation results verify the correctness of the relevant theoretical analysis of the ultra-reliable MU-MIMO based on the ?-? shadowed fading model,and prove that it can be generalized and applied to almost all classical fast fading situations.The research conclusions of this thesis have good flexibility and universality,which are helpful to analyze the energy efficiency,latency and reliability of different CSI,and break the limitations of the classic fast fading model.