Broadcasting in radio networks of unknown topology

as undirected graphs whose nodes know only their own label and the labels of
their neighbors. Broadcasting completes if all the nodes in the graph receives the
message send by the source node. In every time step, the nodes in the graph act
either as a transmitter or as a receiver. The node acting as a receiver gets a message
if and only if exactly one of its neighbors act as a transmitter. If at least
two neighbors transmit a message, then the receiver does not receive any of
the messages. We call this as collision. The assumption is that, if a node receives
more than one message in a time step, then the effect is exactly same as that
of no neighbors sending a message. In other words, a node cannot distinguish between
collision and silence.

I will present some recent results on how efficiently a message can be broadcast
in this model. We will also see some lower bounds on the time needed for broadcast.