Research And Implementation Of RPL Routing Protocol For Aerostat Device Ad-hoc Networks

With the improvement of the intelligence of the aerostat,the aerostat will be equipped with more intelligent electronic devices.The mutual communication and cooperative operation between electronic devices are the basis of intelligentization.The traditional wired way will not only occupy a lot of space on the aerostat,reduce the carrying capacity of the aerostat,but also bring difficulties to the initial design and later maintenance of the aerostat.The wireless sensor network(WSN)and RPL routing protocol are used to reduce the cable weight and improve the load capacity.The improvement of the flexibility and expansibility of the aerostat device Ad-Hoc networks will greatly enrich the role of the aerostat and play an important role in the promotion of high-altitude exploration.First of all,the research background of the aerostat device Ad-Hoc networks and the research and development status of RPL routing protocol for the aerostat device Ad-Hoc networks are introduced in this thesis.The existing device networking method of the aerostat focuses on the data collection network,resulting in a relatively single data flow direction.This thesis applies the RPL routing protocol to the aerostat device Ad-Hoc networks to realize the function of multiple data flow and realize the function of mutual communication between devices.This thesis elaborates the network characteristics and the concept of RPL routing protocol of aerostat device Ad-Hoc networks,and introduces the related technologies of routing protocol of aerostat device Ad-Hoc networks,such as wireless sensor network technology and routing protocol implementation technology.Secondly,the related principles and construction process of RPL protocol are deeply studied.Aiming at the problems of overlong convergence time and excessive control overhead in the process of routing construction,a networking optimization algorithm for efficient and low overhead RPL routing protocol is proposed.By aggregating DAO messages across nodes and uniformly confirming the aggregated DAO messages,the algorithm effectively reduces the control overhead and shortens the convergence time of route construction.In order to meet the requirement of reliability for RPL routing protocol,an optimal algorithm for selecting the optimal parent node is proposed.The algorithm takes the real-time load and the number of DIS messages sent by the parent node as the optimal parent node metric,and improves the original optimal parent node switching mechanism to reduce the routing failure time caused by route switching.Then,this thesis introduces the software architecture and hardware platform of the RPL routing protocol of the aerostat device ad hoc network.The design and implementation of each key functional submodule of the routing protocol software of the aerostat device ad-hoc network RPL are described in detail,including listening module,DIO,DAO,DAO-ACK,DIS message sending and receiving module,trickle timer module,routing update module,pre-routing module,post-routing module and virtual file module.Based on the Open WRT open source operating system,this thesis uses C language to implement RPL routing protocol.Building a test platform to test the function and performance of RPL routing protocol software system.By comparing the convergence time and control overhead of routing construction,the experimental results show that the improved RPL routing protocol can not only effectively reduce the control overhead of routing protocol,but also shorten the convergence time of routing construction.By comparing the path switching time,the experimental results show that the path switching time of the improved RPL routing protocol is obviously reduced.Finally,the work of this thesis is summarized and the next research work and direction are pointed out.