Interference Management Based On Cell Association In Ultra-dense Networks

The diversification of user terminals brought about by the development of technology and the popularization of the Internet of things have caused the rapid growth of mobile data traffic.In order to meet the needs of users and ease the pressure on network capacity,traditional cellular networks have gradually turned to miniaturization and densification,and eventually formed ultra-dense networks.The deployed micro base station has low power,small service range,and few service users.The associated users have strong burstiness and asymmetry,so dynamic TDD technology is introduced to improve the adaptability of the base station.However,the densely deployed micro base stations and dynamic TDD technology also bring about problems that need to be resolved,such as association selection,cross-slot interference,and increased energy consumption.This paper studies the interference management of ultra-dense networks in dynamic TDD scenarios.It conducts key research on association selection between users and base stations,base station configuration,and power control,so as to achieve the purposes of suppressing interference,reducing energy consumption,increasing load balance,and user throughput.First,this paper describes and summarizes the association problems in ultra-dense networks and interference problems in the dynamic TDD scenario of ultra-dense networks.This paper analyzes their technical sources,technical definitions,components and classifications.This paper analyzes the current problems that need to be solved urgently,and lays a theoretical foundation for subsequent research.Then,for the problems of cross-slot interference and cell association,this paper proposes an interference management scheme that combines cell association and dynamic TDD allocation.This solution adjusts the user's associated base station selection and the ratio of the uplink and downlink configuration of the base station by adding constraints such as cross-interference and load limitation to complete the goals of reducing interference and increasing load balance and user throughput.For this scheme,this paper designs a two-layer iterative algorithm,using the generalized Benders decomposition concept to decompose the original problem into two sub-problems,using the inner twoway matching algorithm and the outer gradient descent to solve the problem.Simulation results show that the proposed scheme is superior to the comparison algorithm in increasing throughput and load balancing.Finally,for the unresolved specific uplink and downlink sequence in the base station configuration and the cross-slot interference between users that have not been considered,this paper proposes an uplink and downlink exchange interference management scheme based on interference cost and power control.This solution adjusts the uplink and downlink sequence of the base station in each time slot and the transmission power of the associated users to reduce interference,energy consumption,and increase user throughput.Aiming at the scheme,this paper proposes a two-layer exchange algorithm,which uses the cost of interference to decouple the interference between base stations and convert the original problem into several sub-problems.In this paper,the inner layer iterative algorithm is used to obtain the transmission direction request of each time slot of the base station and the associated user transmission power and the calculation amount is greatly reduced.The outer switching algorithm responds selectively to the base station switching request and finally obtains the result.The simulation results confirm that when the scheme designed in this paper is compared with the existing algorithm,it can effectively suppress interference and increase user uplink and downlink throughput.