Research On High-speed Rail Network Optimization Based On LTE System

With the gradual development and maturity of our country's 4G network system,operators actively respond to the call of "speed-up and fee-reduction".Various "unlimited package" services are rapidly introduced and popularized.Mobile Internet access has become the main way of mutually beneficial network access.The per capita DOU of operators shows a rapid growth trend.At the same time,the mileage of high-speed railway in China is increasing rapidly.High-speed railway has become an important means of transportation for people to travel.It is of great practical significance to analyze and study the LTE network coverage and optimization of high-speed railway.Because the speed of high-speed rail generally reaches about 300 km/h,LTE network coverage and optimization have special characteristics,such as the penetration loss caused by train compartment airtightness,Doppler frequency shift characteristics caused by high-speed train operation and frequent switching problems,linear extension characteristics of high-speed rail track,numerous tunnels and bridges,etc.All of these bring great challenges to LTE wireless network signal coverage and Optimization in high-speed railway train.This paper will introduce the network architecture of LTE system and some key technologies adopted,and analyze in detail its flattened network architecture characteristics and two key technologies of OFDM and MIMO to elaborate the advantages and disadvantages of LTE network optimization,laying a theoretical foundation for subsequent research.At the same time,the particularity of wireless environment under high-speed operation is analyzed concretely,and the specific solutions to the problems of Doppler frequency shift,frequent switching and poor signal penetration caused by high-speed operation are put forward.Then,the LTE network layout and coverage under high-speed environment are planned according to the principles,steps and contents of general network optimization.Cover problem and switching problem optimization are discussed in detail and case studies are carried out.Combining with the optimization project of Baolan High Speed Railway LTE Special Network,the paper collects the operation data of the existing network and predicts the network capacity scientifically.By means of signaling analysis,road test analysis and traffic statistical analysis,the paper illustrates the optimization scheme of LTE network coverage and signal quality along Baolan High Speed Railway,and also illustrates the network operation before and after optimization.By comparing and analyzing the indicators,the achievements of this project optimization are demonstrated.