ons, however. 27.11.6 Adding it all up The interesting part of all these rules of thumb for conventional reuse is that we can multiply them together or add up the decibel count to get a reasonable estimate of ca- pacity changes. Going from six-sector AMPS cells to three-sector GSM cells, for exam- ple, is worth 1 dB for the channel reduction from 30 to 25 kHz, 5 dB greater resistance to interference, and -3 dB for the sector change, a total of 3 dB. This suggests that this change will increase the capacity of the same cell layout by V2, or 40 percent. 27.12 Conclusion This exposition of the principles used for managing capacity on conventional reuse sys- tems gives a picture of the complex issues facing cellular engineers managing interfer- ence on rapidly growing systems. Of course, these issues are managed quite differently in the CDMA network, which uses an N = 1 reuse pattern where all carrier frequen- cies are used by every cell. We turn our attention to these issues in the next chapter. 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. Conventional Reuse Principles 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 CDMA Principles for Multicellular Systems In this chapter we present the code division multiple access (CDMA) equations for one server and for multiple servers and then discuss the assumptions held within the equa- tions. We then apply the equations in general (to both directions) and specifically to the forward and reverse directions. This addresses many of the issues involved in moving the theoretical concept of CDMA into the practical world of cellular telephony. We close the chapter with a discussion 