Design And Implement Of Clock Synchronization And Timing Devices For Mobile Communication Networks

This paper describes a design of synchronized clock transmission system and equipment.This equipment is created to resolve the question of transmitting synchronized clock in the TD-SCDMA network.To research and develop a suit of this system equipment could receive economic behalf and usable value.In the mobile telecommunication field,TD-SCDMA is a TDD system.For improve frequency spectrum usable efficiency,the system switch up and down physical channel timeslot by employ strict synchronized clock.This system needs every unit in the network to synchronize clock.In the constructing application of mobile telecommunication, it need to establish so many network access devices to carry out wireless cover, thereby, there are thousands upon thousands access devices need to let clock synchronize to each other. Above mention access device is called base station (NodeB) in the mobile network.The traditional method of clock synchronization is to install a GPS receiver or BEIDOU receiver in the base station, at the same time, it should join a GPS or BEIDOU satellite antenna.This method aim to let all base station clock synchronize with satellite clock, thereby, achieve at the different place base station's clock synchronization. Due to GPS or BEIDOU satellite antenna should install in an open place, to keep the GPS or BEIDOU receiver could receiver one satellite signal at every time.The cable between antenna and base station could not lay long-distance, so, this require base station device set-up close to satellite antenna.Hence, in the impacted area, there is a trouble of build in base station device.On the other hand, the cost of cable is so high and it has much attenuation as long as distance.The paper describe the synchronize clock system to resolve a series of engineering problems.The system's motive is to reduce build cost and easy to worker install base station device.The synchronize clock system equipments are made up of clock outside unit and clock inside unit.The clock outside unit takes charge receive satellite signal and transmits pulse-per-second signal to clock inside unit.The clock inside unit takes charge receive signal from clock outside unit and recover it to pulse-per-second signal.There is a fiber to link the two devices.The whole clock synchronize system implements a protocol from this project forward. The protocol could be called the remote clock transmit protocol,it can ensure the precision of synchronize clock in transmitting at a long distance.The protocol complete consult ISO's OSI to design every layer function and it provide necessary outlying block status message report interface and operating and maintenance interface.At first,the paper expatiate the idea of remote clock transmit protocol.Then,it analyses the principle of system device design and basic implement flow.The system gains consumer's praise,and immediately extend to the project.As a result of pressing time and limited manpower,the remote clock transmit system has some shortages.lt needs a long time to consummate.The ultimate aim is to apply every clock transmit project.