JPL's Wireless Communication Reference Website

Chapter: Cellular Telephone Networks

Cellular Radio

Cellular phone networks use cellular frequency reuse. In the cellular reuse concept, frequencies allocated to the service are reused in a regular pattern of areas, called "cells", each covered by one base station. In mobile-telephone nets these cells are usually hexagonal. To ensure that the mutual interference between users remains below a harmful level, adjacent cells use different frequencies. However in cells that are separated further away, frequencies can be reused.

  Typical frequency reuse plan for 7 different radio frequencies, based on hexagonal cells. Radio channels are indicated by color. In fact some problems in cellular frequency assignment are solved using map coloring theory.  

Particularly in the United States, the term "cell phone" is often used by the public when a wireless phone is meant. The cellular approach was proposed and developed predominantly by the Bell System, in the U.S. in the early 70's, after the regulatory agency FCC has asked for an upgrade of the existing radio telephone service. The FCC had the foresight to require:

Start page of video
from Short Course by BMRC

Video from Wireless Communications Networks Short Course

"In wireless communication, we attempt to accommodate as many users as possible, and the way we do this is by very dense frequency reuse. We split the area that we want to cover into many small "cells" and in each of these cells we use a different frequency. If we use a frequency in one geographical area, we want to reuse it in another area. Relative to the size of the cell, we want to make the distance between the cells that use the same frequency as small as possible. The price that we pay is that we get interference from one cell to other cells. So we have to build a system in which the receivers are relatively immune to interfering signals. .....

Embedded QuickTime Video

Examples of systems using cellular frequency reuse are GSM and AMPS.

Coverage of cellular telephone systems by the year 2000.

There was an estimated 13,000,000 users of cellular phones in the U.S. alone in 1995, and marketeers expected that the cellular market growed by more than 25% per year for the next five years. Worldwide sales of mobile phones was around 500 Million in 2003 and is expected to reach 1 Billion around 2012.

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JPL's Wireless Communication Reference Website 1993, 1995.