Chapter 1

Introduction

This chapter presents the case for opportunistic routing and related work. We will first introduce the background of multihop wireless networks (mesh networks, sensor networks, mobile ad hoc networks, vehicular ad hoc networks, etc.). We then point out the routing challenges in multihop wireless networks. Secondly, we discuss general wireless multihop routing, including traditional routing (AODV, DSR, etc.), geographic routing, context-based routing and opportunistic routing. We will discuss the motivation of these routing techniques, how they evolved, and their advantages and disadvantages. We will then discuss related opportunistic and collaborative techniques, including cooperative communication, opportunistic scheduling, network coding, multiple AP collaboration, etc. This will help to put opportunistic routing in perspective. We will also introduce related issues about opportunistic routing, including capacity studies of multihop wireless networks, multirate routing, energy-efficient routing, and link-quality measurement, etc.