s, a cheaper and more plentiful pathway. 7.5 Conclusion The GSM set of standards has proven highly successful in Europe, as well as in other nations around the world. The standardization of the entire system, rather than just the air interface, can be seen as part of the larger process of the socioeconomic unifica- tion of the European Union. However, GSM is roughly equivalent in the digital services it provides and in capacity with the North American cdmaOne standard, which we will turn to next. After that, we will explore the issue of the competition to support more digital traffic and become a world standard that is now developing between the latest version of GSM and the new cdma2000 and W-CDMA standards. 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 The CDMA Principle With the basics of cellular worked out in Advanced Mobile Phone Service (AMPS) and the basics of digital radio telephony developed in the Global System for Mobility (GSM), cellular engineers turned to the task of using a new, complex technology that had po- tential to provide even better performance than time division multiple access (TDMA). That technology was code division multiple access (CDMA), an implementation of spread spectrum. In CDMA, multiple signals are sent from the same tower on the same frequency at the same time. Signals are distinguished not by time or frequency but by a code attached to each signal. At the receiving end, the signal is distinguished from all other signals by its code and is extracted from them. This simple-sounding principle actually requires some very sophisticated mathemat- ics, as well as sophisticated engineering, particularly in the realm of power control. In this chapter we will explore these details of the CDMA principle and look at its imple- mentation in the cdmaOne standard