Space-Time Wireless Channels

Chapter 2. Signal Transmission

Before we can understand wireless communications, we must first understand what is meant by the wireless channel and how it distorts transmitted information. The wireless channel imposes the fundamental limitations on the data rate between transmitter and receiver. Hence, the wireless channel imposes the ultimate limitation on what types of information services may be offered in a given frequency band.

Compared to other types of communication channels (wires, waveguides, optical fibers. etc.), the wireless channel is quite data-hostile. There are two reasons for this: low power and unpredictable fading. This chapter concentrates on the unpredictable fading that occurs in a wireless link. As we will see, wireless channels ...