An Optimization Scheme For Sharding Blockchain Based Heterogenous IoT System

With the excellent features of security,immutability,and decentralization,blockchain systems are being increasingly used in smart cities,financial technology,and other fields.The Io T system is a promising application of blockchain.Utilizing the abovementioned characteristics,the Io T system can realize functions such as massive device collaboration and distributed data storage,improve the availability,security,and robustness of the Io T system,and expand the application scenarios.Due to the heterogeneity of Io T devices in terms of network,computing power,storage,etc.,unreasonable blockchain sharding schemes will make the computing power uneven distribution among sharding.This problem will reduce the security and efficiency of the blockchain system.This thesis makes a specific analysis of this problem,and completes the following two parts of the work:(1)Proposing the computing power evaluation scheme for blockchain Io T devices.Considering the Io T devices' diversity and heterogeneity,the thesis firstly analyzes the calculation model of the Po W consensus algorithm.Besides,the network condition also has a vital effect on the consensus efficiency.This scheme combines the network dynamic condition and the device's computing power together,reflects the device efficiency when participating in the blockchain consensus process.The experiments show that the scheme can evaluate the distribution of computing power in the system and provide a numerical basis for scheduling;(2)Proposing a distributed blockchain system sharding scheme with a standard from algorithm-(1).It elects the local computing power advantage nodes and expands the sharding with neighbor nodes' interaction.This scheme can perform a computing power even scheduling process.It eventually makes each sharding's computing power summary being approximately the same.This can avoid the decrease in system efficiency caused by uneven computing power distribution.In the experiments,this research has realized the computing power dispatching process in the real distributed system and simulated the operation results of the algorithm under the large-scale distributed network structure by using distributed simulation software and graph data sets.Through experiments,we have verified the effectiveness and stability of the above scheme.Experimental data shows that this scheme can realize the even scheduling of Io T devices between shardings without sacrificing the decentralization characteristics of the blockchain system.