Research On Load Balancing And Admission Control Algorithm In 5G RAN Slicing

With the popularization and development of the 5th Generation Mobile Networks(5G),Radio Access Network(RAN)has produced three major application scenarios and many types of network services.Due to the low flexibility of traditional network design and development,it is difficult for telecom operators to extend it for various vertical use cases nowadays.RAN slicing is a new network architecture that multiple different virtualized and independent logical networks can share the same physical network infrastructure.Each network slicing is an isolated endto-end network,so it can meet the various requirements of a specific application,and a variety of future vertical applications can be realized at a lower cost than private radio networks.In the research of 5G RAN slicing,for one thing,new problems related to differentiated coverage slice,user association,and resource allocation have brought new challenges to RAN load balancing problem.For another,the construction of service guarantee framework with slices’ Service Level Agreement(SLA)guaranteed makes the admission control problem of RAN slicing a new research hotspot.This thesis is based on scientific research cooperation project of enterprises and institutions," Research on Key Technologies of B5G Network System".We address the load balancing and admission control algorithms for 5G RAN slicing.Considering static cellular networks and dynamic heterogeneous networks respectively,we model user association,resource allocation,and SLA guaranteed in the differentiated coverage of slicing networks.We propose the target problem of load balancing and admission control of RAN slicing,and give the corresponding solution algorithm.The main work of the thesis is as follows:1)The concept and technical implementation of 5G RAN slicing are reviewed,and the related researches on load balancing and admission control,which were the focus of the thesis,were summarized.First,the thesis introduced the architecture and implementation of 5G network slicing and RAN slicing.Next,the resource allocation strategies in 5G RAN slicing were summarized.Finally,the thesis gave the current research,problems and challenges of load balancing and admission control for 5G RAN slicing,and discussed the problems of slice priority,slices’ SLA guaranteed,and dynamic changes of scenario in the existing researches to clarify the research direction of the thesis.2)For the load balancing problem of differentiated coverage of slices and uneven allocation of slice resources in 5G RAN slicing,a joint user resource allocation,user association,and slice resource allocation algorithm with low complexity was proposed.For the 5G cellular network scenario with differentially covered network slicing,a performance index to measure the load balancing of 5G RAN slicing was constructed,namely the load balancing utility function.The thesis proposed an optimal load balancing problem for 5G RAN slicing.The problem was decomposed into three sub-problems of user association,slice resource optimization,and user resource allocation,and they were solved separately.Based on the solution process of the three sub-problems,the joint user resource allocation,user association,and slice resource allocation algorithm was proposed.Simulations verified the performance gain of the proposed algorithm.The simulation results showed that the proposed algorithm could adapt to the scenarios with different requirements for the user transmission rate of different slices in the 5G RAN slicing cellular network,effectively improved the rationality of user association and user transmission rate distribution.3)For the admission control problem of differentiated coverage of slices and slice SLA differentiation in 5G RAN slicing,a joint slice-level and base-station-level admission control algorithm with low complexity was proposed.For the 5G dynamic heterogeneous network scenario with differentially covered network slicing,the admission control problem was modeled into two parts:slice-level admission control and base-stationlevel admission control.The thesis defined user-and-slice-based service request queues,and designed revenue and cost functions.An optimal admission control problem for 5G RAN slicing was proposed.The problem was decomposed into two sub-problems of slice-level admission control sub-problem and base-station-level admission control sub-problem,and they were solved based on Lyapunov optimization theory and greedy strategy,respectively.Next,the slice-level and base-station-level admission control algorithm was proposed.Simulations verified the performance gain of the proposed algorithm.The simulation results showed that the proposed algorithm could adapt to the scenarios where different slices had different SLA requirements in the 5G RAN slicing heterogeneous network.It ensured the stability of all service request queues,and at the same time,service providers could obtain the highest time-average profit.