The Journal of China Universities of Posts and Telecommunications ›› 2021, Vol. 28 ›› Issue (2): 38-47.doi: 10.19682/j.cnki.1005-8885.2021.1004

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Blockchain-based collaborative edge caching scheme for trustworthy content sharing

Zhou Yutong, Li Xi, Ji Hong, Zhang Heli   

  1. Key Laboratory of Universal Wireless Communications,Beijing University of Posts and Telecommunications, Beijing 100876, China
  • Received:2020-10-12 Revised:2020-12-24 Online:2021-04-30 Published:2021-04-30
  • Contact: Li Xi

Abstract: Moving data from cloud to the edge network can effectively reduce traffic burden on the core network, and edge collaboration can further improve the edge caching capacity and the quality of service ( QoS). However, it is difficult for various edge caching devices to cooperate due to the lack of trust and the existence of malicious nodes. In this paper,blockchain which has the distributed and immutable characteristics is utilized to build a trustworthy collaborative edge caching scheme to make full use of the storage resources of various edge devices. The collaboration process is described in this paper, and a proof of credit (PoC) protocol is proposed, in which credit and tokens are used to encourage nodes to cache and transmit more content in honest behavior. Untrusted nodes will pay for their malicious actions such as tampering or deleting cached data. Since each node chooses strategy independently to maximize its benefits in an environment of mutual influence, a non-cooperative game model is designed to study the caching behavior among edge nodes. The existence of Nash equilibrium (NE) is proved in this game, so the edge server (ES) can choose the optimal caching strategy for all collaborative devices, including itself, to obtain the maximum rewards. Simulation results show that the system can save mining overhead as well as organize a trusted collaborative edge caching effectively. 

Key words: caching, blockchain, collaborative edges, consensus mechanism, game theory 

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