erms of Use as given at the website. Base Station Planning Base Station Planning the coverage map is the triple-point of three cells, so keeping the grid means resisting temptation. We believe that seeing the longer view will pay off when demand for wire- less service starts to grow in these areas, and the reduction in pilot pollution means be- ing able to serve more demand with the same number of cells. The coverage job is complete when the service area is covered by enough cells to serve the forecast demand with good radio signals and enough CDMA capacity to ensure low blocking. 33.2 Downtilting and Lowering Antennas In the cellular world, good radio performance is not always a good thing. In fact, the entire cellular principle is one of managed interference, having a strong signal from serving base station and comparatively weak signals from others. We want to reduce the range of a base station as its cell acquires new, nearby neighbors. Radio propagation can do strange things depending on terrain and ground surface features. Radio valleys can appear when a far-away base station has a clear line of sight to a hilltop or building being served by nearer, local base stations. We need to re- lieve this pilot pollution by reducing the range of the far-away base station. Turning down pilot power sounds reasonable, but it seldom works on CDMA systems. When an antenna face is attracting too much traffic, lowering its pilot power will send that traffic to other sectors served by other antenna faces. Most of the time this is a bad thing to do because the interfering component in CDMA is not the pilot signal but the channels being used by other subscribers. In Sec. 28.1.4 we explained that serving these signals on an alternative antenna face actually uses more of the CDMA radio re- source than serving them on their highest-path-gain face. The only way to reduce the interference is to reduce the radio signal path gain of interfering cell sectors. We can shrink a cell radius by reducing the path gain of the antennas. As lo