lures of different components tend to be correlated, then this should be noted in the plan. An example would be that one sector failing drives the other transmit amplifiers to nearly full power so that they are more likely to fail as well. Once the component reliabilities and correlations have been cataloged, the service provider must decide what level of reliability to offer for each base station. Is an occa- sional base station outage a tolerable event? And how good does the service have to be during an outage? The answers to these questions should be firmly in place in the form of a base station reliability plan as part of the base station planning process. The base station reliability plan is the foundation of the maintenance plan and standard oper- ating procedures for operations, administration, and maintenance (OA&M). 33.10 Conclusion In this chapter we have discussed the options available for planning the equipment to be placed at base stations to provide coverage for subscribers and meet peak demand with appropriate levels of blocking and acceptable QoS at reasonable cost. 3We might be able to tell a lot about the planning of a wireless telephone system by the me- chanical condition of the cars in the parking lot. If they are maintained only when they break down, then our confidence in the resulting telephone system may be reduced. 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 Mobile Switching Center (MSC) Planning The mobile switching center (MSC) is the heart of the wireless network. The wireless network, like an arterial network, is a fan-out network, and the MSC is the single point from which all voice calls and data transmissions fan out for mobile-terminated calls and is also the central processing point for all calls coming in from mobile-originated calls. Like a heart,