Optimization Of RPL Routing Protocol Based On 6LoWPAN

The emergence of the IEEE 802.15.4 standard and the establishment of the 6LoWPAN working group have made it possible to use the IP protocol in wireless embedded networks,speeding up the interconnection of the Internet of Things with the Internet and promoting the development of Internet of Things technologies.WSN is an important part of IoT technology.While the birth of 6LoWPAN makes the combination of IP technology and traditional wireless sensor network well,the emergence of new technology also makes the traditional routing protocol unsuitable.RPL is an IPv6-based low-power lossy-network distance vector routing protocol designed for LLNs networks.RPL routing protocol makes a more comprehensive design for wireless network topology construction,node routing selection and optimization.However,be lack of explicit rules for routing metrics and optimal parent selection in routing leads to many details to be improved and perfected in practice.In this thesis,the application,structure,principle and implementation of RPL protocol are analyzed and introduced in detail.Based on above,aiming at the problems such as unbalanced energy between nodes and limited network lifetime in RPL protocol routing,the fusion routing metric D_R and corresponding objective function is established by considering the hop count,power consumption and link quality,which realizes the mechanism of dynamically selecting the optimal parent node according to the node location,reduces the energy loss of the node in the routing process and improves the life of the node as well.In addition,this thesis analyzes the construction of downlink routing in RPL protocol in detail.It is found that there are many DAO messages in downlink routing construction,resulting in large energy loss of nodes and a new downlink routing mechanism is proposed in view of this problem.Finally,we use the Cooj a simulator in the Contiki OS to simulate the above design.The simulation results show that the D_R routing metric proposed in this paper has a great improvement on the survival time of the network and the delivery of the data packet rate compared with the original routing metric.Compared with the original downlink routing method,the improved downlink routing method designed in this paper improves the overall network performance.