  A linear interference network is considered. Long-term fluctuations (shadow
fading) in the wireless channel can lead to any link being erased with
probability p. Each receiver is interested in one unique message that can be
available at M transmitters. In a cellular downlink scenario, the case where
M=1 reflects the cell association problem, and the case where M>1 reflects the
problem of setting up the backhaul links for Coordinated Multi-Point (CoMP)
transmission. In both cases, we analyze Degrees of Freedom (DoF) optimal
schemes for the case of no erasures, and propose new schemes with better
average DoF performance at high probabilities of erasure. For M=1, we
characterize the average per user DoF, and identify the optimal assignment of
messages to transmitters at each value of p. For general values of M, we show
that there is no strategy for assigning messages to transmitters in large
networks that is optimal for all values of p.
