The Study Of Low Overhead Time-sync For Wireless Sensor Networks

The wireless sensor networks (WSNs) compose with large amount of low-priced mini sensor nodes. The sensor nodes form a self-organization and multi-hop network system by wireless communication. With progress of microelectronics, computer science and wireless communication technology, the practicality of wireless sensor networks get great improvement. Time synchronization is a base and important factor in wireless sensor networks.First, this paper introduces significance and characteristic of sensor networks and time synchronization. Then, the basic knowledge about time-sync is presented. Introduce network time protocol (NTP) and four representational time synchronization protocol for wireless sensor networks. Base on the introductions, it analyses the reasons that NTP can't be used in wireless sensor networks, and discusses the advantages and disadvantages about the four time-sync protocols. The time-sync message delivery method and the principle that reduce the time-sync error are especially analyzed in FTSP. The mechanism of time-sync message in FTSP is improved, owning to the special request of energy cost at habitat monitoring. Referencing the maximal node degree arithmetic of cluster arithmetic, the concept of next level node degree (NLND) is raised. Using the next level node degree, some nodes of wireless sensor networks are picked out to send time-sync message actively. It can reduce the traffic of time-sync. Referencing the method of statistics, data-filter arithmetic for regression table is raised. Contrast to the FTSP, the influence of improved method to stability, robustness, astringency and precision is analyzed. Finally, this paper presents the qualifications of low overhead Time-Sync method and data filter arithmetic.Time-sync for wireless sensor networks is related to many different factors. Only using academic analysis, it can't get a reliable estimate for time-sync method. In the future, we will study the simulating method of time-sync, validate the capability of time-sync method, and depending on the result of simulation give further improvement. The final goal is practical application in habitat monitoring of this method.