Research On Cluster-based Multi-hop Routing Technology Of Internet Of Things With High Energy Efficiency And Low Delay

With the development of Internet of Things(IoT),the era of"Internet of Everything" is coming.The multi-hop routing technology will be widely applied in the ubiquitous interconnection due to its advantages of strong scalability,distributed operation and flexible networking.Cluster cooperation is one of the commonly used methods for multi-hop routing technology.It can achieve less network energy consumption and higher transmission reliability through data interaction or control information interaction between nodes.However,due to the instability and asymmetry of wireless links as well as the limited energy and communication capabilities of smart devices,it is still the research focus and difficulty in this field to design cluster-based muti-hop routing transmission schemes with high energy efficiency and low latency for practical applications.In view of the above problems,this dissertation summarizes two kinds of cluster cooperation models according to the data transmission characteristics of the centralized control network and distributed self-organizing network in IoT.Then considering the deficiency of cluster cooperation in existing researches of hierarchical routing,on-demand routing and opportunistic routing,respectivley,the improved algorithm is proposed,and a detailed system model and mathematical theoretical derivation are given.Finally,the simulation results verify that the proposed scheme can further improve the energy efficiency and reduce the end-to-end transmission delay.Specifically,the research content and innovation of this dissertation mainly include the following three aspects:(1)Aiming at the problem of low network lifetime caused by the energy difference of nodes in the centralized control network of IoT,this dissertation studies cluster-based energy-efficient hierarchical routing,and proposes an energy-efficient clustering algorithm based on routing spanning tree.Firstly,the network nodes are grouped according to the geographical location by using the spectral clustering method to avoid the problem of excessive energy consumption of cluster member due to uneven cluster head distribution,and Dijkstra shortest path routing algorithm is used to construct the initial inter-cluster routing spanning tree.Then,the energy consumption of each node acting as cluster head and non-cluster head is deduced respectively,and the energy balance equation is constructed by the ratio of nodes between estimated energy consumption and current residual energy.A cluster head selection algorithm based on energy balance is proposed to optimize the energy dissipation among nodes,and the intra-cluster routing spanning tree is constructed in each cluster.Finally,the boundary node path routing is optimized to reduce network energy consumption,and a final routing spanning tree is formed.The simulation simulates the generation process of the routing spanning tree and verifies the effectiveness of the proposed scheme in terms of network lifetime,energy dissipation and coverage ratio.(2)Aiming at the problem of high retransmission and low energy efficiency in the distributed self-organized network of IoT,this dissertation studies energy-efficient on-demand routing based on cluster cooperation,and proposes a cluster-based energy-efficient cooperative data packet transmission scheme.Firstly,the utility function is designed by considering the geographical location,residual energy and expected energy consumption of neighbor nodes,and an iterative cluseter recruitment algorithm with a low energy consumption ratio is proposed.Then,in order to improve the energy efficiency of data transmission between clusters and ensure that the packets are transmitted along the shortest initial path,a two-stage cooperative packet transmission mechanism between clusters is proposed.The process is equivalent to virtual Multiple-Input-Multiple-Output communication,and the transmit beamforming is designed to align the channel coefficient vectors of the cluster head in the receiving cluster,which improves the probability of successful reception of the cluster head and reduces unnecessary retransmission.Simulations verify that the proposed scheme can effectively reduce the network energy consumption,prolong the network lifetime and enhance transmit efficiency per energy,which indicates the proposed scheme achieves a better tradeoff between energy consumption and packet arrival ratio.(3)Aiming at the high requirement of transmission delay in the distributed self-organized network of IoT,this dissertation studies a low latency opportunity routing based on cluster cooperation,and proposes a cluster-based low latency opportunity cooperative packet transmission scheme.Firstly,a cluster-based opportunistic transmission mechanism is proposed and determine the cluster head,the set of sending nodes and the set of receiving nodes to form a cluster.The opportunity cooperative packet transmission process is equivalent to iterative virtual MIMO communication to improve transmission reliability.Then,the intra-cluster cooperative data transmission model is analyzed.In order to reduce the end-to-end transmission delay,the single-hop transmission distance maximization problem is modeled as a transmission beamforming optimization problem with limited total power,and an iterative transmit beamforming strategy is proposed,which uses a gradient approximation method to approximate the numerical solution of the optimal transmit beamforming vector.Simulation results prove that the proposed scheme can shorten the end-to-end transmission delay,increase the number of successful packet transmissions,and improve the packet arrival rate and transmission efficiency.To sum up,this dissertation mainly studies cluster-based multi-hop routing schemes with high energy efficiency and low delay.According to the different scenarios and performance requirements of IoT data transmission,the corresponding network topology and transmission model are established,and a complete practical algorithm is designed.The theoretical analysis and simulation results verify the effectiveness of the research work in this dissertation and provide reference value for different application scenarios of IoT.