abstract—this paper considers heterogeneous coded caching
where the users have unequal distortion requirements. the server
is connected to the users via an error-free multicast link and
designs the users’ cache sizes subject to a total memory budget.
in particular, in the placement phase, the server jointly designs
the users’ cache sizes and the cache contents. to serve the
users’ requests, in the delivery phase, the server transmits signals
that satisfy the users’ distortion requirements. an optimization
problem with the objective of minimizing the worst-case delivery
load subject to the total cache memory budget and users’
distortion requirements is formulated. the optimal solution for
uncoded placement and linear delivery is characterized explicitly
and is shown to exhibit a threshold policy with respect to the total
cache memory budget. as a byproduct of the study, a caching
scheme for systems with fixed cache sizes that outperforms the
state-of-art is presented.