  We study random linear network coding for broadcasting in time division
duplexing channels. We assume a packet erasure channel with nodes that cannot
transmit and receive information simultaneously. The sender transmits coded
data packets back-to-back before stopping to wait for the receivers to
acknowledge the number of degrees of freedom, if any, that are required to
decode correctly the information. We study the mean time to complete the
transmission of a block of packets to all receivers. We also present a bound on
the number of stops to wait for acknowledgement in order to complete
transmission with probability at least $1-\epsilon$, for any $\epsilon>0$. We
present analysis and numerical results showing that our scheme outperforms
optimal scheduling policies for broadcast, in terms of the mean completion
time. We provide a simple heuristic to compute the number of coded packets to
be sent before stopping that achieves close to optimal performance with the
advantage of a considerable reduction in the search time.
