Hachem et al. formulated a multiaccess coded caching model which consists of a central server connected to K users via an error-free shared link, and K cache-nodes. Each cache-node is equipped with a local cache and each user can access L neighbouring cache-nodes in a cyclic wraparound fashion. In this paper, we take the privacy of the users’ demands into consideration, i.e., each user, while retrieving its own demanded file, cannot obtain any information on the demands of the other users. By storing some private keys at the cache-nodes, we develop a novel transformation approach to turn any non-private coded caching scheme (satisfying some constraints) into a private one.

This paper studies the multiaccess caching systems formulated by Hachem et al., including a central server containing$N$files connected to$K$cache-less users through an error-free shared link, and$K$cache-nodes, each equipped with a cache memory size of$M$files. Each user has access to$L$neighbouring cache-nodes with a cyclic wrap-around topology. The coded caching scheme proposed by Hachem et al. suffers from the case that$L$does not divide$K$, where the needed number of transmissions (a.k.a. load) is at most four times the load expression for the case where$L$divides$K$. Our main contribution is to propose a novel transformation approach to smartly extend the MN scheme to the multiaccess caching systems, such that the load expression of the scheme by Hachem et al for the case where$L$divides$K$, remains achievable in full generality. The resulting scheme has the maximum local caching gain (i.e., the cached contents stored at any$L$neighbouring cache-nodes are different such that each user can totally retrieve$L M$files from the connected cache-nodes) and the same coded caching gain as the related MN scheme. Moreover, our transformation approach can also be used to extend other coded caching schemes (satisfying some conditions) for the original MN caching systems to the multiaccess systems, such that the resulting scheme achieves the maximum local caching gain and the same coded caching gain as the considered caching scheme.

This paper considers the multiaccess coded caching systems formulated by Hachemet al., including a central server containing$N$files connected to$K$cache-less users through an error-free shared link, and$K$cache-nodes, each equipped with a cache memory size of$M$files. Each user has access to$L$neighbouring cache-nodes with a cyclic wrap-around topology. The coded caching scheme proposed by Hachemet al.suffers from the case that$L$does not divide$K$, where the needed number of transmissions (a.k.a. load) is at most four times the load expression for the case where$L$divides$K$. Our main contribution is to propose a noveltransformationapproach to smartly extend the schemes satisfying some conditions for the well known shared-link caching systems to the multiaccess caching systems. Then we can get many coded caching schemes with different subpacketizations for multiaccess coded caching system. These resulting schemes have the maximum local caching gain (i.e., the cached contents stored at any$L$neighbouring cache-nodes are different such that the number of retrieval packets by each user from the connected cache-nodes is maximal) and the same coded caching gain as the original schemes. Applying the transformation approach to the well-known shared-link coded caching scheme proposed by Maddah-Ali and Niesen, we obtain a new multiaccess coded caching scheme that achieves the same load as the scheme of Hachemet al.but for any system parameters. Under the constraint of the cache placement used in this new multiaccess coded caching scheme, our delivery strategy is approximately optimal when$K$is sufficiently large. Finally, we also show that the transmission load of the proposed scheme can be further reduced by compressing the multicast message.