In this paper, we propose a scheme for the problem of cache-aided multi-user private information retrieval with small caches, in which $K$ users are connected to $S$ non-colluding databases via shared links. Each database contains a set of $N$ files, and each user has a dedicated cache of size equivalent to the size of $M$ files. All the users want to retrieve a file without revealing their demands to the databases. During off-peak hours, all the users will fill their caches, and when required, users will demand their desired files by cooperatively generating query sets for each database. After receiving the transmissions from databases, all the users should get their desired files using transmitted data and their cache contents. This problem has been studied in [X. Zhang, K. Wan, H. Sun, M. Ji and G. Caire, \tqt{Fundamental limits of cache-aided multiuser private information retrieval}, IEEE Trans. Commun., 2021], in which authors proposed a product design scheme. In this paper, we propose a scheme that gives a better rate for a particular value of $M$ than the product design scheme. We consider a slightly different approach for the placement phase. Instead of a database filling the caches of all users directly, a database will broadcast cache content for all users on a shared link, and then the users will decide unitedly which part of the broadcasted content will be stored in the cache of each user. This variation facilitates maintaining the privacy constraint at a reduced rate.
翻译:在本文中,我们提出了一个计划,解决缓存式多用户私募信息检索和小型缓存的私募私募私募私募私募私募信息的问题,其中,用K美元将用户通过共享链接与用S$的非冷藏数据库连接起来。每个数据库都包含一套美元的文件,每个用户都有相当于美元文件的专用缓存。所有用户都希望在不向数据库透露其需求的情况下检索一个文件。在缓存时,所有用户都将填充其缓存,必要时,用户将通过合作为每个数据库生成查询机来要求他们想要的文件。在收到数据库的传输后,所有用户都应利用所传送的数据及其缓存内容获得他们想要的文件。这个问题已经在[X.Zhang,K.Wan,H.Sun,M.Ji和G.Cairei,\ tqt{缓存式多用户的多用户私人信息检索的基本限 、IEEEE. Transad.comun.,2021] 中, 用户将要求他们需要的文件。在这个文件中,我们提议一个计划,在从数据库中,每个存储用户的缓存数据库中提供一个比Unationalentality 中,我们建议一个比Uness 更精确数据库的用户更精确的用户更精确的存储量计划。