looking to consolidate vendors and save money and because they will have many em- ployees traveling to other facilities within the company. Giving every employee a cellu- lar telephone is easier than trying to track each one down through the private branch exchange (PBX). These are areas where we want to encourage subscriber demand to grow because we can add base stations in these locations without the burden of acquiring or building ad- equate backhaul transport. We have discussed backhaul under the premise that we have to find a way to get transport to base stations that follow subscriber demand. It is often more cost-effective to find a way to get that demand to follow the transport op- portunities we already have. However, we need to be careful when we do this. Contin- uing with the example of adding a picocell for a major corporation, we may find our- selves in trouble when all these employees head for home at five o'clock and get stuck in the same traffic jam at peak time on our most overburdened cell. We should not turn down the contract because of this problem, but we should not be blindsided by it either. 45.1.3 Existing MSC capacity No matter how carefully we engineer a wireless telephone system, some of its MSCs are busier than others. More specifically, some of the MSCs are closer to reaching their capacity saturation limit, where they will run out of a critical resource. The MSCs with extra capacity are better places to add base stations because they do not require the ad- dition of a new MSC. Encouraging growth in the regions with extra MSC capacity makes better use of the existing MSC resources than adding subscribers in places where the MSC is near ca- pacity limits. Even if we are buying more equipment for an existing MSC, this is still a lot less expensive than installing a whole new switch. We should identify areas where the MSC has a lot of extra capacity and encourage growth in these areas. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright