  We explore the performance of coded caching in a SISO BC setting where some
users have higher link capacities than others. Focusing on a binary and fixed
topological model where strong links have a fixed normalized capacity 1, and
where weak links have reduced normalized capacity $\tau<1$, we identify --- as
a function of the cache size and $\tau$ --- the optimal throughput performance,
within a factor of at most 8. The transmission scheme that achieves this
performance, employs a simple form of interference enhancement, and exploits
the property that weak links attenuate interference, thus allowing for
multicasting rates to remain high even when involving weak users. This approach
ameliorates the negative effects of uneven topology in multicasting, now
allowing all users to achieve the optimal performance associated to $\tau=1$,
even if $\tau$ is approximately as low as $\tau\geq 1-(1-w)^g$ where $g$ is the
coded-caching gain, and where $w$ is the fraction of users that are weak. This
leads to the interesting conclusion that for coded multicasting, the weak users
need not bring down the performance of all users, but on the contrary to a
certain extent, the strong users can lift the performance of the weak users
without any penalties on their own performance. Furthermore for smaller ranges
of $\tau$, we also see that achieving the near-optimal performance comes with
the advantage that the strong users do not suffer any additional delays
compared to the case where $\tau = 1$.
