The Research And Implementation On GAINZ WSN MAC Protocols And Network Platform

After deeply studying on the IEEE802.15.4/ZigBee standard and wireless sensor network operating system TinyOS,this paper has designed and implemented wireless sensor network platform based on the GAINZ sensor node.The specific research and implementation includes:Deeply study on the MAC protocols of WSNs(Wireless Sensor Networks),analyze and summarize the main influence factors of energy-consumption of MAC protocols. Research on the core realization mechanism of mainstream MAC protocols,analyze their characteristics,merits and demerits.Aiming at the disadvantages of MAC protocol in 802.15.4 standard,offer three improved mechanisms for the MAC protocol of 802.15.4 standard to realize the low-consumption issue:The first one is improved channel access mechanism based on the priority,which integrates the advantages of distributional MAC protocol to decrease the collision ratio when the traffic is high;The second one is the enhanced backoff mechanism,which can reduce the energy-consumption of the whole network by postponing CCA(Clear Channel Assessment) operation through calculating the remaining busy time of the channel;The third one is the improved CSMA/CA algorithm which optimize the backoff window size according to the past transmission condition in order to decrease packet collision ratio,results in the power saving and throughput improvement.Test the third scheme to inspect the performance with NS-2 simulator and analyze the result.Deeply research on the TinyOS operating system and its key technologies,design and implement the GAINZ hardware driver module in TinyOS to transplant TinyOS system to the GAINZ platform.Due to the inefficiency in the original GAINZ protocol stack and operating system in SDK,offer a new combination design of IEEE802.15.4/ZigBee protocol stack and TinyOS system.This design effectively meets the needs of highly concurrency for sensor nodes,results in system stability improved.Integrates the GAINZ hardware platform,TinyOS-based communication protocol stack and the improved background management platform to a new development platform.Finally,based on this platform,proceed the temperature and light intensity monitoring test and test all the platform for availability and performance,and analyze the results.