Optimum Design Of Wireless Communication Signal Covering Based On Shenzhen Metro TETRA System

Today,subway has become the most preferable choice of public transports for citizens.It plays a crucial role in the public transportation system of the entire city.It provides a much secured,efficient,and better travel environment for passengers.And a wireless communication system can improve the quality of the communication on subways,increase its effeciency,and as well as to ensure steady operations.As a significant subsystem in subway communication system,the reliability of the wireless communication system directly affects a safe and efficient operation of the carriages.Within the operation,communications or data transfers among personnels using mobile devices,or between them and non-device users are highly depended on this system within the MRT operations.Setting up a wireless communication system within subways is to provide a good communication environment for people.Hence,to ensure a full coverage at every accessible corners in the stations and carriages is crucial.To achieve this,an optimization is to make a suitable selection of a subway network coverage depending on the actual situation.Tests and network optimization need to be done immediately after setting up the coverage in order to make sure the coverage meets the original design requirements,which are to provide the best possible communication services for people,as well as to ensure a safe and efficient operation of the subways.TETRA system,which has currently been used at almost every subway as a wireless communication system both in China and overseas,is also widely used in every subway lines in Shenzhen.This techology uses a two-carrier base station in all stations.All platforms,halls and side platforms are covered with strong signals using antennas;all sections between stations are covered with strong signals using leaky coaxial cables;and all tops of parking spaces and train tunnels are covered as well using omnidirectional antennas.However,weak signal coverage and no signal coverage are found unavoidable with this type of wireless coverage upon using.Hence,different ways of coverage need to be studied and improved accordingly.This project first studied the current whereabouts of subway wireless communication systems in and outside of China and their future development.It not only introduced the widely-used subway wireless communication system,but also pointed out its existing coverage problems along usage in the subways in Shenzhen.Based on the existing problems,we emphatically studied and analyzed the no-coverage sections along Line 7 of Shenzhen Subway.By studying the field data collected and analyzing some scientific calculations,we found out the problems existed and also provided a solution plan.We applied the solution plan into use and tested it in field.We made detailed records after each test,and obtained a final test report through a series of data comperisons and analysis.In a word,this project has solved the existing subway wireless communication system in Shenzhen through analyzing the related professional knowledge,scientific application of all techniques and experimenting.It also will provide a potential technical support to the designs,constructions and operation maintenance of this system for its future operations in subways.