Introduction

Network-wide broadcasting in MANETs provides important control and route establishment functionality for a number of unicast and multicast protocols. In this chapter, an overview is presented of the recent progress of energy-efficient broadcast and multicast in wireless ad hoc networks.

Notice that, in general, there are four basic techniques for energy-efficient communication (Jones et al., 2001).

1. The first technique is to turn off nonused transceivers to conserve energy. Then, we need to schedule, for every node, when it should sleep, when it should be idle, when it should receive, and when it should transmit such that a networking task is finished in a certain time period while simultaneously saving the energy cost.

2. The second technique is scheduling the competing nodes to avoid wasting energy because of contention. This can reduce the number of retransmissions and increase the nodes' lifetime by turning off the nonused transceivers for a period of time when they are not scheduled to transmit or receive. (This was studied in Chapter 4.)

3. The third technique is to reduce communication overhead, such as to defer transmission when the channel conditions are poor.

4. The fourth technique is to use power control to conserve energy. Each node will dynamically adjust its transmission power based on the downstream neighboring nodes to a level that is sufficient to reach the downstream neighboring node(s). This has the added advantage of reducing interference with other ongoing transmissions.