  In this paper we consider the two-user broadcast channel and we characterize
its stable throughout region. We start the analysis by providing the stability
region for the general case without any specific considerations on transmission
and reception mechanisms. We also provide conditions for the stable throughput
region to be convex. Subsequently, we consider the case where the transmitter
uses superposition coding and we consider two special cases for the receivers.
The first one is when both receivers treat interference as noise. The second is
when the user with a better channel uses successive decoding and the other
receiver treats interference as noise.
