Section 7.1: From Radiotelephone to Cellular Telephones

Mobile telephones have changed over the last 20 years. Originally they were supported by an analog radio network, but the limitations of radio transmission quality forced a change in technology to what is now known as cellular service.

Cellular telephones have become a normal part of our lives. The industry has experienced explosive growth, and aggressive marketing has made cellular telephones affordable for almost everyone. They can be purchased for a few dollars, and in some cases, the phones are given away when a user signs a contract for 1 year.

Now, the industry is changing again. Growth has forced the cellular industry to begin looking for newer technologies that will support the millions of cellular subscribers. The need for better fraud control and security has also pushed cellular providers into changing their networks. Digital transmission techniques have allowed the cellular industry to offer new services that may compete with local wireline services, while providing better fraud control and security.

All this change has also brought a level of confusion. There are many choices facing new cellular service providers when building networks, and existing cellular service providers must make difficult decisions about which technology to deploy in their networks.

Making these decisions especially hard is interoperability. Cellular telephones must be able to work in any network since mobile subscribers "roam" outside of their service provider's network. Roaming is one of the premiere features that led to the widespread success of cellular telephones. Users...