ipment. This terminal equipment performs the same function as the transceiver, amplifier, and antenna of a mobile telephone. How- ever, since it is not mobile, it can be powered by the local electrical system or a solar or other power generator. Instead of being an integral component of the cell phone, it ter- minates in a household jack, just as wireline service does in the United States. Cus- tomers can then attach any kind of phone or data terminal in the residence or work- place. The terminal equipment certainly will have a directional antenna pointed at the nearest base station, which will both improve call quality and reduce the interference it otherwise would generate for other cells. One additional technical problem is created by the directional antenna of the termi- nal unit, as illustrated in Fig. 3.2. If a new base station is built closer to the customer, 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. The User Terminal Key Radio Concepts Before After Figure 3.2 Adding a cell with fixed, oriented antennas. it is necessary to reorient the antenna toward the closest base station. This requires an expensive visit by a technician to every WLL unit with a directional antenna. The anten- nas would not have to be redirected immediately, but until it is done, the terminal unit will be interfering with a base station closer than the base station that provides it with service. In CDMA, more interference means fewer calls per cell, so the new configuration will not reach optimal capacity until all WLL terminal unit antennas are redirected to the nearest base station.1 Adaptive phased arrays, smart antennas that can be reoriented electronically, might be used at WLL terminal stations. This might make it possible to re- orient these antennas without visiting each location. However, this is an innovative idea, and it may turn out not to be eith