Caching in Heterogeneous Networks With Per-File Rate Constraints

We study the problem of caching optimization in
heterogeneous networks with mutual interference and per-file
rate constraints from an energy efficiency perspective. A setup
is considered in which two cache-enabled transmitter nodes and
a coordinator node serve two users. We analyse and compare
two approaches: (i) a cooperative approach where each of the
transmitters might serve either of the users and (ii) a noncooperative
approach in which each transmitter serves only the
respective user. We formulate the cache allocation optimization
problem so that the overall system power consumption is minimized
while the use of the link from the master node to the
end users is spared whenever possible. We also propose a low complexity
optimization algorithm and show that it outperforms
the considered benchmark strategies.
Our results indicate that significant gains both in terms of
power saving and sparing of master node’s resources can be
obtained when full cooperation between the transmitters is in
place. Interestingly, we show that in some cases storing the most
popular files is not the best solution from a power efficiency
perspective.