NOMA-based Control And User Plane Separation In Radio Access Networks

Facing the densely deployed cellular networks and users' high-speed data requirements in the future,the tightly coupled control coverage and data transmission functions in the traditional closed network architecture will inevitably bring about problems such as insufficient resources and poor network performance.The technology of Control and User Plane Separation(CUPS)uses high and low frequency collaborative networking.The Control Base Station(CBS)of the Control Plane(CP)works in the low frequency band and is mainly responsible for the control coverage,the Traffic Base Station(TBS)of the the User Plane(UP)works in the high frequency band.Therefore,the architecture of Control and User Plane Separation in Radio Access Network(RAN)can bring better coverage performance,higher transmission rate,lower energy consumption and more convenient management.However,in the architecture of Control and User Plane Separation in RAN,users must be covered by the CBS in order to apply for high-speed data transmission service from the TBS.Therefore,it is very important to improve the user coverage probability of CP.However,the existing research usually adopts Orthogonal Frequency Division Multiple Access(OFDMA)technology in CP,so the spectrum resources are limited and cannot meet the future massive user access.Non-orthogonal Multiple Access(NOMA)technology can access multiple users in one channel at the same time,which makes it possible to improve the number of users and spectrum utilization.Therefore,NOMA technology can be introduced into the architecture of Control and User Plane Separation in RAN and the coverage probability,spectrum efficiency and energy efficiency are worth studying.In addition,previous studies on the spectrum efficiency of the UP only focus on UP,and do not consider the influence of CP on the user,which leads to the spectrum efficiency of UP is relatively ideal.In view of the above two issues,in this thesis the system model of NOMA-based Control and User Plane Separation in RAN is established,the specific research contents are as follows:In this thesis,NOMA technology is introduced into the architecture of Control and User Plane Separation in RAN under NOMA-based Control and User Plane Separation in RAN.The coverage probability,spectrum efficiency and energy efficiency performance of CP are studied by using the characteristics of NOMA technology to access two users on the same channel at the same time.By using the knowledge of probability theory,random geometry theory and queuing theory,the interference of adjacent base stations is analyzed,and on this basis,the coverage probability,spectrum efficiency and energy efficiency of CP are deduced when only NLOS transmission path is available.According to the numerical results,compared with OFDMA technology,NOMA technology has higher coverage probability,and the maximum performance can be improved by about 84%.At the same time,the performance of NOMA technology is significantly improved compared with OFDMA technology in terms of spectrum efficiency and energy efficiency.Aiming at the problem that the spectrum efficiency of UP is too idealized without considering the influence of CP on users,this thesis proposes a UP research scheme of joint CP coverage characteristics.On the basis of the continuous and stable control coverage provided by the CP for users,the spectrum efficiency of UP is analyzed.The CBS will select the TBS with the best performance for users to provide services.Considering that there are LOS and NLOS transmission paths from TBS to user in the UP,Rice fading channel model is adopted in the UP.Finally,MATLAB software is used to design and realize the simulation model of the architecture of Control and User Plane Separation in RAN.The simulation results show that with the increase of the density of TBS,the spectrum efficiency of UP will increase first and then tend to be stable.The spectrum efficiency can be improved by increasing the user density or CBS density and reducing the Signal to Interference plus Noise Ratio threshold.