voice and data links for subscriber service, there are radio links for signaling, including paging and access channels. 5.3 Conclusion Now that we have introduced the basics of the wireless signal path and the radio ar- chitecture of base stations, cells, and sectors, we can look at AMPS (FDMA), GSM (TDMA), and CDMA systems in greater depth in the following chapters. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Basic Wireless Telephony Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Source: CDMA CAPACITY AND QUALITY OPTIMIZATION Chapter Analog Wireless Telephony (AMPS) Although many people think that Advanced Mobile Phone Service (AMPS) was the first mobile telephone system, it has a predecessor. Before AMPS, Improved Mobile Tele- phone Service (IMTS) was available, but it wasn't cellular. Each city was served by just one radio tower. AMPS was the first cellular service in the United States and a revo- lutionary technology in its day. No matter how big and clumsy the old AMPS car phones look now, and no matter how primitive the analog FM technology appears to today's engineers, the fundamental principles of AMPS are the same as those of the latest Global System for Mobility (GSM) and code division multiple access (CDMA) technologies. 6.1 The Early Days of Cellular In 1966, two members of the technical staff at Bell Telephone Laboratories, Richard Frenkiel and Philip Porter, realized that service capacity could grow enormously by reuse of voice radio channels. 1 A service area could be divided into cells, and interfer- ence could be managed by making sure that same-channel users were sufficiently far apart. The more aggressively we reuse channels, the more call capaci