Research On Environmental Information Collecting Technology Of Wireless Sensor Networks

Recently, advances in micro-electro-mechanical systems (MEMS) technology, wireless communications technology, digital electronics and embedded system technology have greatly promoted the development of Wireless Sensor Network (WSN). With the features of quick deployment, unattended, autonomous and high reliability, WSN has already become an international research hot spot for its vast application prospect in martial and civil field.This paper is dedicated to the study of key technologies of WSN with battlefield environment information acquisition as the application background. For any environment information acquisition systems, the data acquired in the sensor area must be transferred to the data center by WSN reliably to be processed and the final result will be provided to decision makers. Therefore, data collecting is one of the key issues for WSN. In this paper, features and key technologies of WSN are introduced and a system structure plan for wireless battlefield information collecting network is proposed. The communication protocol and operation system are analyzed while a CTP (Collection Tree Protocol) based on TinyOS operation system is designed and implemented. Then the performance evaluation is done with a programmed upper-layer application.TinyOS, specially designed for WSN, is an embedded operation system which facilitates the development of applications. The basic thought for CTP is tree-like collection. A certain number of collection root nodes are set up in the network and parent nodes will be selected as next hop with sharing of link quality estimate among neighbor nodes so as to set a reliable route to a certain root node. CTP consists of link estimator, routing engine and forwarding engine. Link estimator will estimate the link quality among neighbor nodes. Routing engine will select the parent node according to the link quality and the routes will be under real-time updating. Whenever the route is set, forwarding engine will forward the data so as to complete the reliable data collecting service from source node to sink node.Theory and implementation mechanism of CTP are described in detail in this paper. The performance is also tested in a series of designed simulation experiments. Results proved that this protocol, in the case of smaller network size and less communication load, is of good performance, i.e., shorter time delay and higher transmission efficiency, which basically meets the requirements for WSN battlefield environment information acquisition system.