Introduction

Wireless multihop radio networks such as ad hoc, mesh, or sensor networks are formed of autonomous nodes communicating via radio. Wireless networks have drawn a great deal of attention in recent years because of their potential applications in various areas. For example, WMNs are being used as the last mile for extending the Internet connectivity for mobile nodes. These wireless mesh or sensor networks behave almost like wired networks because they have infrequent topology changes, limited node failures, and so on. For WMNs or WSNs, the aggregate traffic load of each routing node changes infrequently also. A unique characteristic of wireless networks is that the radio sent out by a wireless terminal will be received by all the terminals within its transmission range and also possibly cause signal interference to some terminals that are not intended receivers. In other words, the communication channels are shared by the wireless terminals. Thus, one of the major problems facing wireless networks is the reduction of capacity because of interference caused by simultaneous transmissions. Using multiple channels and multiple radios can alleviate, but not eliminate, the interference. To achieve robust and collision-free communication, there are two alternatives. One is to utilize a random-access MAC layer scheme; this was discussed in detail in Chapter 3. The other is to carefully construct a transmission schedule. One variant, link scheduling in the context of time-division multiplexing (TDM), is the subject of this chapter.