Studies And Developments Of Time Synchronization Of Wireless Sensor Networks

Wireless sensor networks aim at getting real physical information in specific environment. To enhance humankind's ability of information gathering, the wireless sensor networks take advantage of sensor technology and network technology, and get the information, which is full of efficiency and reality in time.As an important module of wireless sensor network stack, time synchronization is the foundation of several modules, such as TDMA access, cooperating sleep, communication scheduler, localization scheme. Based on this background, this dissertation focuses on the studies and developments of the time synchronization of wireless sensor networks.Firstly, there is a discussion of software and hardware platform of wireless sensor networks. In order to get excellent performance, time synchronization module needs the supports from software and hardware. Therefore, the performance of the hardware and software is the foundation of designing and developments of time synchronization module.As a foundational factor, the capabilities of all the hardware modules affect the performance of time synchronization seriously. This dissertation discusses the hardware designing and realization of wireless sensor network node, and analyses the energy cost and communication capability of the modules, including the microprocessor, RF module and power supply module.Software platform supplies the supports of task scheduler, energy management, message trigger, clock trigger, etc. Software platform supports the modules designing and applications effectively, based on the ultra lightweight task scheduler, the stack frame, and the message interfaces of all the modules.This dissertation analyses the error resource of time synchronization on our wireless sensor network nodes. In order to reduce the error of time synchronization, the dissertation designs a new algorithm of time synchronization, named Double Time Resources Feedback Algorithm for Time Synchronization. This algorithm takes advantage of double time resources of high precision, reducing the time error by feedback. At last, this dissertation analyses the synchronization precision, error resource and energy cost.