Research On RPL Routing Protocol Based On 6LoWPAN

With the depletion of IPv4 addresses,the current intercommunication between IPv6 networks and wireless sensor networks has become an important development trend.The emergence of 6Lo WPAN technology has accelerated the integration of the IPv6 networks and wireless sensor networks,making it possible to transmit IPv6 data on the equipment supporting the IEEE802.15.4 protocol.Low power and lossy networks(LLN)as a branch of wireless sensor networks is limited in energy,memory and processing capabilities.As a key technology in LLN,routing protocol has a profound impact on LLN networks performance.The IPv6 based routing protocol for LLN(RPL)as a routing protocol specifically designed for LLN has received widespread attention.Based on the research of existing RPL routing protocols,this thesis proposes two improved RPL routing protocols.The main work of the thesis is as follows:1.For the problem of RPL routing protocol like incomplete routing metrics lead to non-optimal parent node selection and data transmission path is not good enough,an algorithm of(Efficient and low-latency RPL routing protocol based on cross-layer optimization,CL-ORPL)is proposed.The CL-ORPL routing protocol includes three improved mechanisms:(1)CL-ORPL defines a new objective function which comprehensively considers various metrics to improve the optimal parent node selection mechanism;(2)modify the "Source Address" field of the DAO-ACK message to the " Previous Hop Address " field so that the information of the last hop node can be carried through the DAO-ACK message;(3)cross-layer listening to the modified DAO-ACK message,establish horizontal route through the "Previous Hop Address" field and the MAC frame header address.Theoretical analysis and opnet simulation results show that the improved protocol is superior to existing algorithms in terms of average end-to-end delay,success rate and network survival time.2.Aiming at the problem in the current research of RPL routing protocol based on multiple sink nodes such as thunder effect,one-way choice of optimal parent node and unbalanced network load among multiple RPL instances.An algorithm called efficient RPL routing protocol based on bidirectional parent selection in multi-sink(BPSM-ERPL)is proposed.The BPSM-ERPL routing protocol includes three improved mechanisms:(1)using M-DAO message carries data transmission rate information without increasing additional control overhead,so that child node can notify candidate optimal parent node of the requested data rate in advance;(2)the two-way parent node selection mechanism is proposed.Optimal parent node judges whether to establish a connection with the child node according to its own network state.Through the mutual decision between the optimal parent node and the child node,the probability of network congestion is reduced;(3)rational distribution of data among multiple RPL instances is achieved through border routing nodes.Theoretical analysis and opnet simulation experiments show that BPSM-ERPL is superior to existing algorithms in terms of throughput of network,success rate and network survival time.Finally,summarized the research work,and the next research work of RPL routing protocol is proposed.