In this chapter, some simple but also widely accepted models of wireless ad hoc networks are introduced. Notice that WSNs comprise a special subclass of wireless ad hoc networks; thus, when we use the term “wireless ad hoc networks,” we also include WSNs if not specifically clarified. In this chapter, the main focus is on the wireless channel model, the interference model, the energy-consumption model, and the mobility model.

Wireless Channels

The main difference between wireless networks and traditional wired networks is that the wireless devices in a network communicate over wireless channels via wireless transceivers. Thus, to understand wireless ad hoc networks and design efficient protocols and algorithms for wireless networks, we need to understand the characteristics of wireless communications. An important building block of wireless ad hoc network studies is thus the wireless channel model. In the literature, there are a number of wireless channel models proposed and the model presented in this chapter is based on the material contained in Rappaport (1996) and Santi (2005b).

It is widely assumed that a radio channel from a transmitting wireless device u to a receiving wireless device v is established if and only if the received power of the radio signal at node v is above a certain threshold. Let p(u, v) denote the power assigned to node1u to transmit a signal from u to v. We always assume that this power can maintain a reasonably good communication link quality2 from node u to node v.