Design Of Wireless Sensor Network Platform Based On ARM Architecture

Firstly, this paper does some research in the Wireless Sensor Network technology and the protocol of Zigbee. After that, based on the methods of designing embedded system, this paper focuses on the Linux kernel configuration and reduction, the layered software architecture and the data structure optimization, the system booting faster and etc.As a new data-based communication network technology, Wireless sensor network synthesizes the technology of wireless communication, network, System on Chip (SoC), distributed information processing and etc. At the same time, ZigBee is a new short-distance wireless communication technology, characterizing by its low-cost, small-scale, minor energy consumption and low transmit rate. Besides, the Zigbee protocol has the abilities of automic building the network, automatic connect to the network, choosing routes and self recovery. Therefore ZigBee gradually becomes the preferred network protocol for WSN. Basically speaking, the Linux kernel of the embedded systems should be configured and reduced before we use them. This paper follows the basic methods of Linux kernel configuration and reduction, does some deep research of the options of the Linux kernel, and finally gets the kernel image of the wireless sensor network nodes. Before the configuration and reduction, the kernel image is 1.2MB. However, after the configuration and reduction, the kernel image only takes 275KB, which dramatically reduces the memory area it takes.Secondly, according to the Zigbee Protocol and the IEEE 802.15.4 Standard, this paper designs the layered software architecture of the system platform. For the sake of the limited memory of the nodes, this paper optimizes the data structure of the primitives in the protocol, which effcially reduces 590 bytes of the memory area. Based on these work, this paper tests and compares the efficiencies before and after the optimization, which shows that the optimized primitive data structure can effectively reduce the system sources and enhance the system performance.Thirdly, based on the fast-dispalyed, fast-booted requirements of the wireless sensor network, this paper optimizes the system booting process by changing the booting script files and the parallel booting-up of the system services, on the ground of researching the Linux system booting process detailedly. After the optimization, the booting time of the system reduces from 20.2s to 9.5s, which notably develops the booting process.Finnally, we design a wireless temperature sensor network system which contains 20 nodes. Then we verify the basic functions of the nodes and the basic network functions, such as network building, the device acess to the network and etc. And through collection of the temperature of the lab, we verify the data transfer of the network.