Research On Blockchain-based Spectrum Dynamic Sharing Mechanism

With the rapid rise of mobile data traffic,terminal access and Internet intelligence,the use of spectrum resources is becoming more and more frequent,and the contradiction between spectrum supply and demand will become increasingly prominent.In order to support higher data rate transmission and expand system capacity,in the future,the use range of spectrum will expand to the era of full spectrum.Traditional spectrum management schemes suffer from interactive security,privacy disclosure and low spectrum utilization.Taking advantage of decentralization,anonymity and trust of blockchain technology,it can ensure that each spectrum transaction can be confirmed and saved safely and reliably without paying fees to thirdparty platforms.At the same time,the blockchain's distributed database promotes the real-time sharing of spectrum information and improves the utilization of spectrum resources.Therefore,this thesis proposes a blockchain-based spectrum dynamic sharing mechanism,which fully considers the security,time variability,spectrum reusability and other factors of spectrum sharing.By improving the consensus protocol and structure of blockchain,the problems of large resource consumption,high transaction delay and low throughput are alleviated.In order to reduce the complexity and the overhead and increase the flexibility of the mechanism in the spectrum sharing scheme,this thesis builds a layered spectrum sharing blockchain framework,which is designed from the perspective of operators and mobile users respectively.This thesis proposes a spectrum sharing mechanism between users based on DAG blockchain to overcome the problems of low throughput and high latency of traditional blockchain technology by improving the structure and consensus mechanism of DAG.In order to improve the enthusiasm of users to participate in spectrum sharing,a reputation evaluation mechanism combined with spectrum characteristics is proposed.For the established mixed integer nonlinear programming problem of jointly optimizing the matching rate and delay of users,a new spectrum matching algorithm is proposed,and the efficiency of the algorithm is verified by simulation results.The severe shortage of spectrum resources caused by the excessive number of subscribers will transfer the spectrum demand problem from the bottom users to the top operators.This thesis proposes a spectrum trading mechanism between operators based on consortium blockchain.In order to improve the throughput of blockchain network and reduce computational complexity,this thesis proposes a hybrid consensus agreement combining Po W and PBFT.Deploying spectrum allocation scheme in the smart contract of consortium blockchain ensures the security of spectrum transaction.The spectrum allocation problem among operators is established as a generalized Stackel Berg game and the existence and uniqueness of game equilibrium are proved theoretically.Finally,the numerical simulation results confirm the convergence and superiority of the proposed algorithm to solve the spectrum game problem,as well as the advantages of hybrid consensus protocol in throughput and communication times.