An Approach to Reduce the Redundancy of Placement Delivery Array Schemes for Random Demands

Centralized coded caching schemes have been widely studied in wireless networks. Placement delivery array (PDA) can be used to generate a coded caching scheme with low subpacketization when all the requested files are different. However, all existing schemes based on PDA design treat the request of each user as an independent file, without leveraging the multicast opportunities when one file is requested by several users. In this letter, for any existing scheme based on PDA design, after its coded multicast messages generation, we proposed an approach to remove the redundant multicast messages.