wireless ad hoc networking

Chapter 2
Communication
Protocols
Lionel M. Ni and Yunhuai Liu
One of the most important issues in wireless sensor networks is the data
delivery service between sensors and the data collection unit (the sink).
Although sensor networks and mobile ad hoc networks (MANETS) are
similar to some extent, they are radically distinct in many aspects. Sensor
networks have many unique features, making them more challenging
and in need of further development. Existing routing protocols for sensor
networks can be classified as indicator-based or indicator-free. In this chapter,
we make a comparative study of these protocols. Some open issues and
research directions are pointed out as guidelines for future research work.
2.1 Introduction
In this chapter, we focus on the communication protocols in wireless sensor
networks (WSNs). 1 As one of the most important parts of WSNs, the communication
protocol provides data delivery services between entities. Apart
from the traditional wired or mobile ad hoc networks, there is always one or
a set of special data collection nodes (the sink) that functions as a gateway
between the network and end users. The sink has reliable connections (e.g.,
wired or satellite) to the Internet, powerful processing capabilities, and adequate
power supplies (see Figure 2.1). Due to this routing paradigm, the
25