Blockchain-based Secure Spectrum Sharing Mechanism In Internet Of Things

The advent of the Internet of Everything era has led to an increasing demand for spectrum resources.However,the limited spectrum resources and the access of large number of devices in Internet of Things(Io T)make the spectrum scarcity problem more and more prominent.The existing study shows that the majority of the authorized spectrum is unutilized,but the unauthorized spectrum is extremely crowded.How to effectively and safely utilize limited spectrum resources has become a fundamental challenge for future mobile communication systems.Cognitive Radio(CR)improves spectrum utilization through dynamic spectrum sharing(DSS)technology,which provides an effective method to solve the above problems.However,most of the existing spectrum sharing methods rely on a centralized database,which results in defects such as poor dynamics,low scalability,slow access speed,capacity bottleneck and single point of failure.In addition,the absence of efficient security mechanisms for spectrum resource trading makes users’ privacy suffer from security threats.Some users will make decisions that damage the collective utility due to their self-interest when they know the global information.Focusing on the issues mentioned above,this paper combines CR and blockchain,and utilizes the distributed and non-repudiation characteristics of blockchain to solve the secure spectrum sharing in complex cognitive environments.The main contributions of this paper are summarized as follows:(1)The existing work is analyzed and reviewed in detail from the two aspects of CR and blockchain,and the advantages and disadvantages are expounded.Then,the related work in the field of Io T spectrum sharing is elaborated,and the deficiencies of the existing work are analyzed from three aspects: resource allocation,incentive design and security sharing.(2)Focusing on intelligent sensing and sharing,a blockchain-based two-stage secure spectrum intelligent sensing and sharing auction mechanism(BISA)is proposed,which selects appropriate base stations(BSs)to form a consortium blockchain to guarantee secure and efficient spectrum auction with low complexity.In the first stage,a reverse-auction-based incentive mechanism(RAIM)is presented to provide bidding strategies for the primary users(PUs)and secondary users(SUs)selecting the PU that maximizes the utility.In the second stage,a unit-utility-based auction algorithm(UUA)is proposed to achieve a stable match between PUs and SUs.PUs will select the SU with the maximum unit utility to complete the auction.Then,the transaction records are formed into blocks and uploaded to guarantee the security of transactions.Simulation results show that,compared with the existing methods,the proposed BISA increases the total utility and throughput of SUs by 216.4% and 189.3%,respectively.(3)To address the communication instability caused by the dynamic changing characteristics of network topology in the Internet of Vehicles(Io V)environment,focusing on enhancing security and improving spectrum utilization,a blockchain-based secure spectrum sharing mechanism for Internet of Vehicles(BSF)is proposed.The mechanism uses a consortium blockchain to ensure the security of spectrum sharing,and a Byzantine Fault Tolerance-based Proof of Stake(BFT-Po S)consensus algorithm to achieve consensus in Io V.In this mechanism,to incentivize SUs to participate in spectrum sharing,an insurance contract-based incentive mechanism(ICIM)is designed by introducing the concept of insurance contracts.In ICIM,PUs lease the free spectrum to SUs in exchange for some revenue.At the same time,the PU will provide an insurance contract for the SUs,and the SUs who have signed the insurance contract can apply for loss compensation from the PU in case of transmission failure.Then,a preference-based spectrum allocation algorithm(PSA)is designed to maximize the total utility of SUs.Simulation results show that,compared with existing schemes,this scheme achieves better performance in terms of SUs utility and spectrum utilization,providing more access opportunities for users in IoV.