  We characterize stability regions of two-user fading Gaussian multiple access
(MAC) and broadcast (BC) networks with centralized scheduling. The data to be
transmitted to the users is encoded into codewords of fixed length. The rates
of the codewords used are restricted to a fixed set of finite cardinality. With
successive decoding and interference cancellation at the receivers, we find the
set of arrival rates that can be stabilized over the MAC and BC networks. In
MAC and BC networks with average power constraints, we observe that the duality
property that relates the MAC and BC information theoretic capacity regions
extend to their stability regions as well. In MAC and BC networks with peak
power constraints, the union of stability regions of dual MAC networks is found
to be strictly contained in the BC stability region.
