The Design And Implementation Of The Physical Layer Of The Wireless Sensor Network Node Based On TinyOS

A wireless sensor network is composed of a large number of distributed sensor nodes that are densely deployed either inside the phenomenon or very close to it. These sensor nodes organize themselves into a multi-hop wireless network and cooperate to deliver collecting data to sink nodes.WSN is an important way to obtain informations and has very abroad application foreground on the aspects of environment monitor, medical treatment and army and so on.In this article, we integrate the research and exploitation of the National Development and Reform Commission CNGI R&D/industrialization and experimentation/application demonstration project—"IPv6 wireless sensor networks nodes", based on the characteristics of the two kinds of wireless sensor networks nodes, and from the practical requirement of project, design and implement two kinds of physical layer schemes. Because of the design of all these two schemes are from the degree of guarantee the credible communication of the whole networks, so these two schemes are not only able to implement the functions of physical layer, but also provide the guarantee of the credible transition to the implementation of protocols. The main jobs of this article include:■We analyze and summarize the development of the technology of wireless sensor networks, and deeply discuss the advantages of the embedded operation system TinyOS and the programming language NesC in the exploitation of the sensor nodes.And we anatomize deeply the operational mechanism of the whole operation system to make the operation system migrated on the nodes designed ourselves easily.■We analyze and summarize the function provided by physical layer. These functions include the send of the packet handed down from upper layer, receiving the packets from wireless channel and delivering them to the upper layer, providing the function of carrier sense for the MAC layer, setting the mode of sleep and wake for nodes. At the same time of the design and implementation of the physical layer, we also find the reasonable and effective methods to sustain the final implementation of the physical layer scheme to provide good guarantee for the well-circulation of the whole operation system and the natural communication of the whole networks.■By analyzing the hardware characteristics of the node composed of MSP430F1611 and TR3000 and contraposing the simple and limited functions provided by TR3000, we give an physical layer scheme which uses software to fetch up the disadvantages of hardware. This scheme of physical layer effectively resolves the problems include the packet synchronization, bit synchronization, the problem of extracting time information uneasily because of the demodulation, and the problem of the packet disturbed by the electromagnetic wave in wireless environment. As the results indicate, this scheme of physical layer can provide good communication guarantee for the whole networks.■We analize the characteristics of the node composed of MSP430F1611 and CC1100, consider that the wireless communication chip CC1100 can provide registers which have rich and strong functions, so when design the physical layer scheme based on this node, we focus our job on the building and implementation of a component architecture. This architecture is propitious to the design and implementation of programs.■Aim at testing these two kinds of physical layer schemes, we give a systematic test scheme of physical layer to test every function module entirely. Contraposing the abnormal problems in the process of test, we adjust and consummate the implementation of scheme continuously to guarantee the physical layer to provide credible service and good guarantee to the communication of the whole networks.