Research And Verification Of Networking Technology For Bluetooth Low Energy Mesh

In the wave of the Internet of Things,Bluetooth Low Energy(BLE)technology stands out from many low-power wireless communication technologies by its advantages of long transmission distance,low node energy consumption and low cost.The Bluetooth Special Interest Group has launched the BLE Mesh technology on the basis of BLE,but the BLE Mesh is still immature.In terms of networking,the requirements for node mobility and diversified services are not satisfied.In terms of routing,energy consumption and channel resource utilization are not considered.Therefore,this thesis focuses on the Mesh Profile Version 1.0released by the Bluetooth SIG,analyzes the actual application scenario requirements of BLE Mesh networks,and proposes a hierarchical BLE Mesh network(HBMN)architecture and energy-efficient opportunistic routing mechanism.In the end,the proposed networking architecture and routing mechanism are verified by using computer simulation and n RF52832 hardware platform.The main contributions of this dissertation are as follows:(1)A hierarchical BLE Mesh network architecture is proposed.Firstly,the requirements of BLE Mesh network in fixed-node and mobile node scenarios are analyzed and summarized,respectively.Secondly,based on the scenario requirements,the HBMN is designed,which divides the nodes in the network into a central layer,a traffic layer and a user layer.The nodes in the central layer play the role of centralized control and connect different Mesh networks,which expands the communication range.The number and types of nodes in the traffic layer are the largest,which support diversified services.The nodes in the user layer include various existing low-version Bluetooth devices on the market.The layered BLE Mesh network architecture finally realizes the scalable communication range,the compatibility with lowversion Bluetooth protocols,and the support of diversified services.Finally,considering the network access process of the device and the characteristics of the Bluetooth broadcast channel,the networking rounds and single-hop delay characteristics of HBMN are analyzed.(2)An energy-efficient opportunistic routing mechanism is proposed.This mechanism solves the problems of high energy consumption and low utilization of network resources in the traditional managed-flood-based routing mechanism.The mechanism mainly includes the selection algorithm of candidates set based on the geographical information and packet delivery probability,and a priority ranking algorithm based on Markov chains.Firstly,the selection algorithm of candidates set will utilize the location information and the successful transmission probability to select candidate nodes as relay nodes from the neighbors of the sending node.Then,based on the Markov chain model,the average power consumption of all candidate nodes are calculated by the steady-state probability of the nodes.The states of nodes include sending,sleeping,scanning and receiving.The candidate nodes will be sorted by the priority.Finally,the nodes with higher priority will be selected to relay messages.(3)Based on the Nordic nRF52832 development platform,the proposed networking architecture and routing mechanism are experimentally verified.In terms of networking,the experimental verification of the networking process and the light-switch function is carried out,and the performance is compared with the traditional BLE network.In terms of routing,the function of customized data transmission is added,and the message relay function is experimentally verified.The performance of the proposed energy-efficient opportunistic routing mechanism is analyzed.Simulation and experimental results show that the BLE Mesh network has more advantages in the time of networking and one-hop delay.The proposed energy-efficient opportunistic routing mechanism effectively reduces node energy consumption,prolongs network lifetime,and saves network resources.