Based On The Zigbee Low-power Mac Research And Realization

In recent years, wireless sensor networks have become one of the leading technology in the field of electronic information,which has become the necessary technology in the environmental monitoring, space exploration, medical and remote areas exploration. At the same time ZigBee network as a new member of wireless network, has made great progress in the short-range wireless communications. It has been involved in home control, commercial building automation and factory floor management in the field of wireless sensor network market.IEEE802.15.4 standard is for low-rate wireless personal area networks (Low Wireless Personal Area Network, LR-WPAN) standard, which developed by IEEE, aims at providing an economical, and efficient wireless network for low-power equipments of communications. The physical layer and link layer of ZigBee stack are based on the IEEE802.15.4 standard, and add the network layer and application support sub-layer module, thus achieving large area network coverage. ZigBee has gradually become a popular protocol in the field of wireless sensor communication due to its priority on low-power, low-rate, self-organization, and so on.In wireless senseor networks, network performance depends on media access control (MAC) layer. To reduce power consumption, MAC protocol design is a key issue. MAC protocol for wireless sensor networks research has become the current hot spots.This thesis introduces the ZigBee technology, analyzes ZigBee protocol stack and existing MAC protocol. Then we compare the power consumption of two different MAC protocols with NS2 simulation software. This dissertation focuses on the analysis of S-MAC protocol, which reveals how to solve the power problems in IEEE802.15.4 MAC layer protocol. The ZigBee standard builds on the assumption that infrastructure nodes have a constant power supply. ZigBee therefore does not provide any power-saving mechanisms for routing nodes, which limits the lifetime of battery-powered ZigBee networks to some extent. Based on the problem of power energy for ZigBee network, an improved scheme on ZigBee protocol stack was proposed based on the adaptive S-MAC. And then, a short-range wireless communications platform with the CC2520 RF chip was built. According to Adam Dunkels'theoretical model of power, improved ZigBee protocol reduces power consumption up to 10% -30% in theory when the data traffic is relatively small, and the improved ZigBee protocol stack also increases battery life in the actual test.