he cal- culations necessary for optimal multiuser reception. The claims are that JD offers significant gains in CDMA capacity and that it allevi- ates the near-far problem by allowing differences as large as 20 dB in reverse channels signals. The result of this is that TD-SCDMA does not require high-speed power- control algorithms. Eliminating sophisticated and rapid power control reduces the CDMA capacity overhead for power control. This allows the resource that otherwise would be dedicated to power control to carry subscriber voice or data, increasing ca- pacity. This change also makes the equipment simpler and cheaper. 10.5 Conclusion We have now explored the standards that allow multiple vendors around the world to produce interoperable equipment for CDMA systems. Standards are intended to sup- port the rapid deployment of reliable, compatible, high-quality systems. Implementa- tion in the real world always falls below the ideal of the standards to some degree. As we move forward, we will first provide additional background information in data sys- tems and telephony and then move on to discuss the real-world capacity and quality is- sues, helping you to improve your real-world systems SO that they approach the opti- mal design implied in these 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 Key Telephony Concepts The primary purpose of the cellular system is to carry telephone calls. However, readers with a radio engineering or data systems background will not have an in-depth knowledge of the fascinating history and deep concepts that underlie telephony. The public switched telephone network (PSTN) is a worldwide technological marvel, and much of its technology is adopted and adapted into the wireless network. Part 3, "Key Telephony Concepts," provides knowledge of telephony eng