RF and Microwave Wireless Systems

CHAPTER EIGHT

Wireless Communication Systems

8.1   INTRODUCTION

The RF and microwave wireless communication systems include radiolinks, tropo-scatter/diffraction, satellite systems, cellular/cordless/personal communication systems (PCSs)/personal communication networks (PCNs), and wireless local-area networks (WLANs). The microwave line-of-sight (LOS) point-to-point radio-links were widely used during and after World War II. The LOS means the signals travel in a straight line. The LOS link (or hop) typically covers a range up to 40 miles. About 100 LOS links can cover the whole United States and provide transcontinental broadband communication service. The troposcatter (scattering and diffraction from troposphere) can extend the microwave LOS link to several hundred miles. After the late 1960s, geostationary satellites played an important role in telecommunications by extending the range dramatically. A satellite can link two points on earth separated by 8000 miles (about a third of the way around the earth). Three such satellites can provide services covering all major population centers in the world. The satellite uses a broadband system that can simultaneously support thousands of telephone channels, hundreds of TV channels, and many data links. After the mid-1980s, cellular and cordless phones became popular. Wireless personal and cellular communications have enjoyed the fastest growth rate in the telecommunications industry. Many satellite systems are being deployed for wireless ...