We address energy-aware broadcasting and multicasting from the
perspectives of both energy-efficient and energy-limited operation.
In the former case, it is implicitly assumed that energy reserves
(batteries) can be renewed during the course of network operation, and
a cost is associated with the quantity of energy that is expended.  In
the latter case, each node is equipped with batteries that cannot be
recharged during network operation.  Thus, there is a hard constraint
of a fixed quantity of energy at each of the network nodes.

We review the characteristics of the Broadcast Incremental Power (BIP)
and Multicast Incremental Power (MIP) algorithms, which we developed
in our earlier studies.  We show how they exploit the characteristics
of the wireless medium, and how they can be modified to extend network
lifetime considerably in energy-limited applications.  Our original
models considered centralized operation with omnidirectional antennas.
In this presentation, we discuss issues associated with distributed
implementation, and introduce several distributed versions of BIP.  We
also show how the use of directional antennas affects algorithm design
and performance; most significantly, we show how the use of
directional antennas can result in considerable energy savings, and
hence in greatly extended network life.