Freshness Based Cache Updating in Parallel Relay Networks
Freshness Based Cache Updating in Parallel Relay Networks
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DOI：
10.1109/isit45174.2021.9518003
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发表时间：
2021-05
期刊：
影响因子：
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通讯作者：
Priyanka Kaswan;Melih Bastopcu;S. Ulukus
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文献类型：
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作者：
Priyanka Kaswan;Melih Bastopcu;S. Ulukus
我们考虑一个系统组成的服务器，它接收更新$N$文件根据独立的泊松过程。服务器的目标是通过一个由$K$个缓存组成的并行网络向用户提供最新版本的文件。如果用户收到的文件版本与服务器上当前流行的文件版本相同，则我们认为用户收到的更新成功。我们推导出一个解析表达式的信息新鲜度在用户。我们观察到，新鲜度的文件增加了合并率跨缓存的增加。为了解决多缓存问题，我们首先解决单缓存系统的辅助问题。然后，我们通过尽可能多地将速率合并到单个路由来重新设计并行缓存网络的辅助解决方案。这产生了原始问题的近似（次优）解决方案。我们提供了一个上界之间的差距差距的次最优的解决方案和最优的解决方案。数值结果表明，次优策略非常接近最优策略。
We consider a system consisting of a server, which receives updates for $N$ files according to independent Poisson processes. The goal of the server is to deliver the latest version of the files to the user through a parallel network of $K$ caches. We consider an update received by the user successful, if the user receives the same file version that is currently prevailing at the server. We derive an analytical expression for information freshness at the user. We observe that freshness for a file increases with increase in consolidation of rates across caches. To solve the multi-cache problem, we first solve the auxiliary problem of a single-cache system. We then rework this auxiliary solution to our parallel-cache network by consolidating rates to single routes as much as possible. This yields an approximate (sub-optimal) solution for the original problem. We provide an upper bound on the gap between the sub-optimal solution and the optimal solution. Numerical results show that the sub-optimal policy closely approximates the optimal policy.