Research On Key Technologies Of Wireless Sensor Networks Based ZIGBEE

The rapid development of MEMS (Micro-Electro-Mechanical System), SOC (System on Chip), wireless communication and low-power embedded system promoted the emergence and development of wireless sensor networks (WSN). WSN are networks of wireless nodes that are deployed over a surveillance area and multi-hop self-organizing by wireless communication. WSN is composed of many high-new technologies and became a new technology in the field of communication and computer science, which academe and industry member have attached importance to. The research of WSN has great significance in the human life, environment monitoring, industry automation and military reconnaissance. With such background, this paper explores and researches on a wireless sensor network that is easy and quick to construct the networks, smooth to communicate and small.The main contents of this paper are listed as follows:(1)This paper puts forward the design scheme of the WSN and its nodes after analyzing the short range communication technology and IEE802.15.4/Zigbee specification. We use the ARM7 chip and CC2420 as our hardware platform of WSN. The paper dwells on the implement of ZigBee specification and all the problems which are met during the developing process.(2)Every node of the WSN is required to get its own position. The ZigBee task and the position task are needed to switch with each other. This paper divides the ZigBee task into some small tasks so as to make the switch more quick and smooth. The paper defines the priorities and stacks of physical layer task, MAC layer task and network layer task. At the same time, it brings forward a coordination mechanism of these tasks.(3)This paper designs and realizes a channel switch mechanism for ZigBee. It takes two channel sequences: mimic Bluetooth sequence and chaotic sequence. The chaotic sequence is selected after two sequences having been compared in balance and Hamming relativity. The paper also elaborates how to realize the channel switch mechanism for ZigBee based on geopolitical locations supplied by GPS module. The channel switch mechanism improves the security and stability of the WSN to a great extent.(4)The paper also makes some enhancement in the AODV routing protocol. There were many defects of classic AODV routing protocol in energy-efficient, security and stability when it was applied. This paper put forward two solutions to improve the AODV routing protocol. The first was to adjust the transmission power dynamically. The second was to control the broadcast messages. These solutions were based on GPS information. The simulation results of these solutions in the NS-2 showed that the improved routing protocol was better than the classic routing protocol in the network delay and energy-efficient...