Research On Dynamic TDD In 5G System

With the rapid development of mobile communication network and mobile Internet,the user's communication service has gradually become more volatile and unexpected.In order to meet the increasing demand of users for communication services and to further improve the user's communication quality,the fifth generation mobile communication technology(5G)has been proposed.As a new generation of mobile communication technology that is developed to meet the demand of 2020 and future mobile communications,5G has now become the focus of technological competition in the field of mobile communications in the world.The main application scenarios of 5G include Enhance Mobile Broadband(eMBB),Massive Machine Type Communication(mMTC)and Ultra-relaible and Low Latency Communication(URLLC).This article mainly considers the indoor ultra-dense network scenario in eMBB.In order to meet the rapidly growing business needs of users,dynamic TDD technology is proposed to use in eMBB indoor ultra-dense network scenarios.The technology dynamically adjusts the configuration of the subframes of the base station so as to maximize the satisfaction of the user equipment.Dynamic TDD technology is an important research direction in 5G NR(New Radio Access Technology)technology.This technology also brings certain cross-slot interference while improving overall network performance.This paper focuses on the dynamic TDD technology in 5G indoor ultra-dense network scenario and proposes a scheme to reduce the interference of cross-slot.First of all,this paper presents a dynamic TDD base station clustering method based on graph theory.The difference between this method and the traditional dynamic TDD clustering method is that this method considers both the cross-slot interference between base stations-base stations and user-users.After defining the new threshold of coupling loss,this paper uses graph theory-based clustering method to cluster base stations according to the new coupling loss threshold,so as to reduce the interference of cross-slot and improve the overall performance of the system.Secondly,this paper also proposes an uplink-downlink sub-frame configuration method based on sub-frame update.The subframe ratio and the order of the uplink/downlink sub-frame are updated in a small scale,so as to reduce the number of cross-slot,and further reducing the interference of cross-slot interference between the base stations.Finally,this paper simulates the dynamic TDD base station clustering method and the uplink-downlink subframe configuration based on the subframe update method on 5G simulation platform,and compares the simulation results with the traditional simulation results.Simulation results show that the proposed algorithm can mitigate the cross-slot interference and improve user SINR and rate.