基于联盟链的运营商最佳缓存策略

Optimal Caching Strategy of Operators Based on Consortium Blockchain

基于区块链的边缘缓存技术可以实现更大范围的内容共享并提高缓存内容的使用效率。针对不同运营商各自建设边缘设备,缓存内容相互隔离,难以共享信息的问题,该文提出一种基于联盟链的边缘缓存系统框架并设计了内容共享和交易流程,实现了不同运营商之间的内容共享。此外,为了降低高维缓存节点的共识开销,设计了基于内容缓存的部分实用拜占庭容错(pPBFT)共识机制,仅选取缓存相关内容的联盟链节点作为验证智能合约的执行节点。最后,将运营商内容共享所带来的收益进行量化并构建为最大化收益的优化问题。通过所提出的内容缓存算法,得到了最优缓存决策的闭式表达式和与内容流行度相关的最优缓存策略。仿真结果表明,在该框架中所提出的共识机制和缓存策略能够有效增加运营商的缓存收益。

The edge caching based on blockchain will achieve a wider range of content sharing,and enhance the efficiency of caching contents.However,different operators build their own edge devices and the cached contents are isolated and have difficulty in sharing information.In this paper,a blockchain-based edge caching system framework and a content sharing and transaction process is proposed,which can realize content sharing between different operators.In addition,a partial Practical Byzantine Fault Tolerant(pPBFT)consensus mechanism based on content caching is designed to reduce the consensus cost of high-dimensional caching nodes,in which only the consortium nodes that cache the relevant content can be selected as execution nodes for validating smart contracts.Finally,through quantifying the benefit obtained by operators’content sharing,the closed-form optimal solution is derived with the aim to maximize the profit by adopting the proposed content caching strategy,and the optimal caching strategy related to the popularity of the content is further developed.Simulation results show that the proposed consensus mechanism and caching strategy based on this framework can effectively increase the operator’s caching revenue.