1 research outputs found
On the Rate-Memory Tradeoff of D2D Coded Caching with Three Users
The device-to-device (D2D) centralized coded caching problem is studied for
the three-user scenario, where two models are considered. One is the 3-user D2D
coded caching model proposed by Ji et al, and the other is a simpler model
named the 3-user D2D coded caching with two random requesters and one sender
(2RR1S), proposed in this paper, where in the delivery phase, any two of the
three users will make file requests, and the user that does not make any file
request is the designated sender. We allow for coded cache placement and none
one-shot delivery schemes. We first find the optimal caching and delivery
schemes for the model of the 3-user D2D coded caching with 2RR1S for any number
of files. Next, we propose a new caching and delivery scheme for the 3-user D2D
coded caching problem using the optimal scheme of the 3-user D2D coded caching
with 2RR1S as a base scheme. The new caching and delivery scheme proposed
employs coded cache placement and when the number of files is equal to 2 and
the cache size is medium, it outperforms existing schemes which focus on
uncoded cache placement. We further characterize the optimal rate-memory
tradeoff for the 3-user D2D coded caching problem when the number of files is
equal to 2. As a result, we show that the new caching and delivery scheme
proposed is in fact optimal when the cache size is in the medium range.Comment: To be submitted for possible journal publicatio