Improved Constructions of Coded Caching Schemes for Combination Networks

Abstract

In an $(H,r)$ combination network, a single content library is delivered to $\left(\genfrac{}{}{0ex}{}{H}{r}\right)$ users through deployed $H$ relays without cache memories, such that each user with local cache memories is simultaneously served by a different subset of $r$ relays on orthogonal non-interfering and error-free channels. The combinatorial placement delivery array (CPDA in short) can be used to realize a coded caching scheme for combination networks. In this paper, a new algorithm realizing a coded caching scheme for combination network based on a CPDA is proposed such that the schemes obtained have smaller subpacketization levels or are implemented more flexible than the previously known schemes. Then we focus on directly constructing CPDAs for any positive integers $H$ and $r$ with $r<H$. This is different from the grouping method in reference (IEEE ISIT, 17-22, 2018) under the constraint that $r$ divides $H$. Consequently two classes of CPDAs are obtained. Finally comparing to the schemes and the method proposed by Yan et al., (IEEE ISIT, 17-22, 2018) the schemes realized by our CPDAs have significantly advantages on the subpacketization levels and the transmission rates.

arXiv comment11 pages

References in corpus (6)

• Fundamental Limits of Caching with Secure Delivery
• Placement Delivery Array Design through Strong Edge Coloring of Bipartite Graphs
• Coded Caching Schemes with Low Rate and Subpacketizations
• A Novel Asymmetric Coded Placement in Combination Networks with end-user Caches
• On Combination Networks with Cache-aided Relays and Users
• Caching in Combination Networks: A Novel Delivery by Leveraging the Network Topology