e capacity to serve mobile telephone customers increased, SO the market grew as well. The new cellular telephone technology grew quickly from a novelty to a way of life; there were hundreds of millions of cellular telephones world- wide by the late 1990s. This growth beyond all early forecasts has made capacity man- agement a key issue in the growth and financial success of cellular service providers. 6.2 The Cellular Principle Prior to the deployment of cellular technology, mobile telephones for an entire city were served by a single tower with a single set of radio channels. The entire New York City area was served by just 14 radio channels and could only support 14 simultaneous mo- bile telephone calls. Adding one channel to the spectrum allocation added just one more telephone call for the entire city. Cellular offered the opportunity for unlimited service, as we saw it then, to as many as a million mobile telephones by the end of the twenti- eth century. Advanced Mobile Phone Service (AMPS) was prepared for this rate of growth. With a hundred towers of 45 channels each, a large cellular system could handle thousands of calls. Because we could split cells repeatedly, there was no obvious limit to growth. We could double the number of base stations to double the system capacity and, if de- mand warranted, double it all again. Using four-to-one cell splitting, 8-mile cells could become 4-mile cells, 2-mile cells, and even 1-mile cells to build a network that would satisfy the market demand for cellular telephones. A library of sophisticated computer engineering tools would calculate channel assignments, handoff radio thresholds, neighbor lists, and a host of other complex parameters. The primary market for cellular telephony was going to be the mobile worker and the business commuter because this was a vehicular telephone technology. There were portable telephone prototypes about the size of a single-lens reflex camera, but they were expensive and had a short battery life. Portable cellular telephones were a cu