论文标题
编码缓存中的盲目更新
Blind Updates in Coded Caching
论文作者
论文摘要
我们考虑了集中式编码的缓存系统，该系统在服务器上可用，其子文件被安置交付阵列（PDA）处方的客户端缓存。我们对库中特定文件替换为服务器上的新文件的问题感兴趣，该文件的内容与已更换的文件相关，并且需要将此更改传达给caches。替换后，服务器只能访问更新的文件，并且不知道其与原始文件的差异，而每个缓存都可以访问PDA规定的原始文件的特定子文件。我们通过假设它们在最大的$ε$子文件中的不同而建模，并旨在减少服务器广播以更新缓存的位置的数量。我们为服务器设计了一种新的优雅编码传输策略，以盲目更新缓存，并确定基于MDS代码的简单方案。然后，在所有线性策略中，我们以最低通信成本$ \ ell^*$得出了相反的界限。对于PDA的两个著名家庭 - Maddah-Ali＆Niesen的缓存计划，以及Tang＆Ramamoorthy和Yan等人的PDA。 - 当更新足够稀疏时，我们的新计划的价格为$ \ ell^*（1 + o（1））$，而使用MDS代码的计划在更新密度时的订单优势。
We consider the centralized coded caching system where a library of files is available at the server and their subfiles are cached at the clients as prescribed by a placement delivery array (PDA). We are interested in the problem where a specific file in the library is replaced with a new file at the server, the contents of which are correlated with the file being replaced, and this change needs to be communicated to the caches. Upon replacement, the server has access only to the updated file and is unaware of its differences with the original, while each cache has access to specific subfiles of the original file as dictated by the PDA. We model the correlation between the two files by assuming that they differ in at the most $ε$ subfiles, and aim to reduce the number of bits broadcast by the server to update the caches. We design a new elegant coded transmission strategy for the server to update the caches blindly, and also identify a simple scheme that is based on MDS codes. We then derive converse bounds on the minimum communication cost $\ell^*$ among all linear strategies. For two well-known families of PDAs -- Maddah-Ali & Niesen's caching scheme and a PDA by Tang & Ramamoorthy and Yan et al. -- our new scheme has cost $\ell^*(1 + o(1))$ when the updates are sufficiently sparse, while the scheme using MDS codes has order-optimal cost when the updates are dense.
