Research On 5G Network Handover Solutions In High-speed Railway Environments

In recent years,the high-speed railway,as a modern transportation mode,has been playing a unique role in relieving inter-city traffic pressure and enhancing people’s travel experience.With the importance of the high-speed railway in modern transportation has been gradually coming to the fore,wireless communication systems on high-speed trains have become particularly important in ensuring passenger experience and improving operational efficiency.In the context of the 5G era,accompanied by the continuous growth in the number of users and the diversification of service demands,as well as the unique characteristics of high-speed rail wireless communication networks,5G public network coverage is facing a series of challenges,and it has become particularly urgent to solve the network coverage problems of the high-speed railway.In the actual road test experiments,the public wireless communication network in the high-speed railway environment still suffers from coverage voids,discontinuous coverage,as well as frequent handovers and interruptions.The success rate of handovers between base stations has a critical impact on the quality of wireless communication.This article conducts analysis and research on related issues.The main work and research results are as follows:(1)In response to issues such as signal strength degradation,weak coverage,and discontinuous coverage encountered during high-speed train travel,an analysis has been conducted,and a novel handover model solution based on beamforming technology for designing adjustable antennas is proposed.This solution introduces phase shifters into the base station antennas,enabling the antennas to generate different downtilt angles and forming a coverage range that encompasses both far-field fixed beam positions and near-field fixed beam positions close to the base station.By utilizing beamforming technology,the solution enhances the received signal quality at the cell edges within overlapping coverage areas between base stations,ensuring continuous coverage and maintaining communication quality without interruption prior to handover.The approach also employs a weight function based on train interval speeds to make corresponding adjustments to handover hysteresis,addressing the issues of premature or late handovers caused by hysteresis.Compared to existing beamforming solutions,the proposed method demonstrates significant improvements in both handover triggering rates and handover success rates,exhibiting high reliability and stability.(2)In consideration of the public network structure in high-speed railway environments,this study proposes an optimized handover model based on an improved 5G Non-Standalone(NSA)control/user plane separation architecture.This approach employs an LTE primary station to control the 5G NR secondary station network structure,fully leveraging the advantages of 4G network coverage while 5G as a shunt node can mitigate the impact of large data traffic on 4G networks.To ensure stable communication during primary station handovers and timely handover triggering,the study utilizes an adjustable antenna handover model designed using beamforming technology.In addition,cell merging techniques are employed to reduce the number of handovers between secondary stations within the primary station,and a5 G base station on-board solution is adopted to effectively reduce the losses caused by wireless signal penetration through the train body.This ensures continuous base station coverage,maintains communication quality prior to handover,and triggers handovers promptly.Compared to the results of road test experiments,the proposed improvement scheme achieves higher handover triggering and success rates while effectively reducing the probability of handover interruptions.