  We propose a scheme to reduce the overhead associated with channel state
information (CSI) feedback required for opportunistic scheduling in
multicarrier access networks. We study the case where CSI is partially
overheard by mobiles and one can suppress transmitting CSI reports for time
varying channel of inferior quality. As a means to assess channel quality and
exploit multiuser diversity we adopt maximum quantile (MQ) scheduling. We show
that the problem of minimizing the average feedback overhead can be formulated
as a Bayesian network problem. A greedy heuristic using probabilistic inference
is proposed to deal with the NP-hardness of the problem. Leveraging properties
of MQ scheduling we first show that networks having tree-like overhearing
graphs admit simple inference. We then present a class of more general network
structures for which exact inference is computationally tractable. Simulation
results are provided to demonstrate the improvements offered by the proposed
heuristic.
