  Fast fading wireless networks with delayed knowledge of the channel state
information have received significant attention in recent years. An exception
is networks where channels are spatially correlated. This paper characterizes
the capacity region of two-user erasure interference channels with delayed
knowledge of the channel state information and spatially correlated channels.
There are instances where spatial correlation eliminates any potential gain
from delayed channel state information and instances where it enables the same
performance that is possible with instantaneous knowledge of channel state. The
key is an extremal entropy inequality for spatially correlated channels that
separates the two types of instances. It is also shown that to achieve the
capacity region, each transmitter only needs to rely on the delayed knowledge
of the channels to which it is connected.
