  We study the content delivery problem between a transmitter and two receivers
through erasure links, when each receiver has access to some random
side-information about the files requested by the other user. The random
side-information is cached at the receiver via the decentralized content
placement. The distributed nature of receiving terminals may also make the
erasure state of two links and indexes of the cached bits not perfectly known
at the transmitter. We thus investigate the capacity gain due to various levels
of availability of channel state and cache index information at the
transmitter. More precisely, we cover a wide range of settings from global
delayed channel state knowledge and a non-blind transmitter (i.e. one that
knows the exact cache index information at each receiver) all the way to no
channel state information and a blind transmitter (i.e. one that only
statistically knows cache index information at the receivers). We derive new
inner and outer bounds for the problem under various settings and provide the
conditions under which the two match and the capacity region is characterized.
Surprisingly, for some interesting cases the capacity regions are the same even
with single-user channel state or single-user cache index information at the
transmitter.
