ultiple base stations and antenna faces. These are areas where CDMA coverage may be adequate but capacity is compromised because multiple servers are competing for the CDMA signal and interfering with each other. We will have more to say about pilot pollution maps in Sec. 48.5. 47.10 Conclusion Radio propagation models use four basic approaches: Distance and general environment Detailed terrain models In-building analysis Ray tracing In the order presented in this chapter, the models grow more precise, providing a greater level of detail, but do not necessarily grow more accurate. Assumptions inher- ent in the models may not match our terrain or equipment in important ways. Nonetheless, propagation calculations are of great value. We can build or purchase computer systems that apply these tools to our wireless networks. They work both as planning guides, as well as troubleshooting tools. Once networks are operational, it is best to supplement these tools with a program of regular measurement. Mathematical models combined with actual measurements give us the best solutions. Having an analysis of radio coverage for our network is useful, but it is not enough. We also need to know where the demand is. Which of the locations on the map have lots of cellular users? We turn our attention to this now in Chap. 48. 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. Propagation Models 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 Subscriber Traffic Modeling Wireless is an unusual industry not only because our customers are mobile while they are using our services but also because we can serve them without knowing quite where t