Research On CoAP Of Ubiquitous Power Internet Of Things

Ubiquitous power IoT is a new type of IoT that makes power business more intelligent and digital,It meet the demand for comprehensive sensing and extensive interconnection of massive business data of power system with power energy as the core,and ensure efficient and stable operation of power system.Constrained Application Protocol(CoAP)is a lightweight application layer communication standard protocol,which is widely used in IoT where various node resource are limited;However,the existing CoAP protocol cannot adapt to the characteristics of ubiquitous power IoT with many nodes,diverse business data and high requirements for flexibility and reliability.In order to meet the efficient and reliable transmission of power business data,there is an urgent need for an application layer communication protocol that can meet the characteristics of ubiquitous power IoT.Based on the in-depth study of CoAP protocol and combining the characteristics of ubiquitous power IoT,this thesis designs the application layer framework of ubiquitous power IoT based on the CoAP protocol,and proposes two improved CoAP protocols for the ubiquitous power IoT.The main research contents are as follows:1.For the massive terminal nodes of ubiquitous power IoT,node resources are limited and reliable transmission is required.Network congestion is pron to cause probelm such as loss of power business data and excessive delay.A link-stability-based CoAP Congestion Control(L-Co CC)algorithm for ubiquitous electrical IoT based on link stability is proposed.The algorithm contains three improved mechanisms.First,three types of message Round-Trip Time(RTT)are used to determine the link status in the network and smoothly estimate the Retransmission Timeout(RTO).Second,the number of retransmission and the jitter value of the message round-trip time introduce the lower RTO limit method and the RTO update aging to minimize unnecessary retransmissions and improve the transmission efficiency under network congestion.2.There is a serious problem that the underlying layer of ubiquitous power IoT uses PLC power line carrier communication,which is not sufficiently integrated with the upper layer CoAP protocol,resulting in data information redundancy and low channel utilization.To address this problem,A CoAP Cross-layer Optimization Algorithm Based on MAC Layer Collaboration(MCP-CoAP)is proposed.The algorithm contains two improved mechanisms: firstly,use MAC and CoAP cross-layer collaboration for congestion control,and then use MAC layer nodes to access the network instead of the CoAP node registration process to minimize the control overhead of the CoAP protocol and improve success rate and throughput of network packet transmission.Finally,the main research work of the whole text is summarized,and further research directions of the CoAP protocol of ubiquitous power IoT is expounded and prospected.