Design And Implementation Of An Application Platform For Internet Of Things Based On Contiki

IPv6is the inevitable trend of the development of network communication. It is bound toreplace IPv4and become the new generation standard of IP communication. The rise ofInternet of Things (IoT) has put forward new demands for common sensor nodes accessingthe Internet. Traditional IP protocol stack is not suitable for wireless sensor nodes, in whichresource and energy are constrained. Under such circumstances, through the continuousexploration and study of many scientific and research institutions at home and abroad, a seriesof protocols that designed for IoT came into being.6LoWPAN is the best solution tointerconnect IPv6network and wireless sensor networks; RPL is a routing protocol thatspecifically designed for low-power lossy networks; CoAP, as a lightweight application layerprotocol, can effectively reduce the power consumption of the nodes and extend battery life.At present, these protocols are still under development and improvement, and surely willbecome part of the IoT standards in the future. The key point of this research is to apply theseprotocols into practice, show the usage and the actual effect of these protocols by materialobject, and design and implement an IOT application platform in line with the direction offuture development.Based on the in-depth study of IPv6and the related protocols, this thesis adopts an end-to-end network architecture according to the IoT application model, and designs a platformwhich consists of mote and gateway two parts. The hardware and software design of thisproject try to meet the versatility and scalability principles, in order to adapt more applicationscenarios and future upgrading.The mote can realize the functions of information sensing and intelligent control byconnecting to a variety of sensors and controllers. The hardware uses STM32F103seriesmicrocontroller as the core control unit and AT86RF231RF chip for wireless data transceiver.It also set aside a variety of bus IO to facilitate the expansion of other sensors and controllers.The software part achieves IPv6network communication based on the uIP and6LoWPANprotocol stack provided by the open source operating system Contiki. A simple networkapplication based on CoAP protocol is also developed.The hardware of the gateway, compared to the hardware of mote, adds an ENC28J60 ethernet controller used to communicate with the wired network. The software ports theforeign open source project6LBR which can realize genuine IPv6routing function andsupports prefix reconfiguration at runtime. When the computer communicates with the motes,the gateway can automaticly identify the target interface type according to the address andforward the data through wireless or wired interface. It plays the role of interconnecting thewired network and the wireless network and is easy to deploy and manage as the entireprocess is transparent to the user.Finally, a series of tests are done on the application platform according to IPSO Allianceinteroperability testing standards. And after the analysis of the performance index of thesystem based on the tests of the packet reception rate, delay and other indicators, some noteswhen using the application platform under some particular situations are put forward, and thedirection of further improvement and optimization are pointed out.