TABLE OF CONTENTS Daniel M. Dobkin
In this chapter, we provide a brief introduction into the topic of networking in general and review the characteristics of several wireless local network technologies. In this review, the reader will encounter real examples of how the concepts introduced in Chapter 1 are put to use in getting data from one place to another wirelessly.
Our treatment is necessarily cursory and emphasizes aspects relevant to our main topic of wireless transmission and reception, giving short shrift to frame formats, management entities, and many other topics directed toward network implementation.
Data networks have existed in various forms since the invention of telegraphy in the nineteenth century. However, the use of data networks has expanded tremendously with the proliferation of computers and other digital devices. Today, networks extend everywhere, and the Internet the network of networks allows computers almost anywhere in the world to communicate with each other using these networks.
Data networks can be organized in a hierarchy based on physical extent. The physical reach of the network is a useful figure of merit both for technical and practical reasons. Information cannot move faster than the speed of light, so as the distance covered by a network grows, its latency the minimum time needed to send a bit between stations grows too. Latency has important consequences on how networks are designed and operated: if the transmitter has to wait a long time for a reply to a message, it makes sense to send large chunks (
