The article following, written by one of the lead engineers in the project, describes the development of AMPS, the first cellular telephone system in the United States. As noted, the project ran for over 12 years and required the services of a "vast number" of engineers at AT&T's Bell Labs. The hundreds of millions of people currently using cellphones, smart phones, and all the other mobile wireless equipment available in the United States, as well as everywhere else in the world, often take these devices and the infrastructure behind them for granted. Until the cellular concept was recognized, it wasn 't clear that many mobile phones could simultaneously share the same channels in a local area. With the cellular concept agreed on, problems such as tracking of cell phones and handoff from cell to cell had to be resolved. Computerized base stations had to be designed and tested. A myriad other important development and design issues and problems had to be resolved. Dick Frenkiel very clearly describes the various engineering problems that had to be solved, step by step, sometimes quite painstakingly. He gives credit to the many teams of Bell engineers who worked on this project. He also points out policy issues involving the FCC that had to be resolved. Competition for scarce radio spectral space was fierce. Competing engineering companies and telephone operators had to be assuaged. In the meantime, I urge you to read on through this exciting description of the genesis of cellular telephony in the United States.

History of Communications

Traffic characteristics of a mobile radio communication system using a dynamic channel assignment scheme which has all channels available at all base stations are derived. In the system with one channel, the traffic characteristics in each zone are exactly obtained. For a multichannel operation, some approximation methods are proposed and some simple examples are also presented.

On Telephone Traffic in a Mobile Radio Communication System Using Dynamic Frequency Assignments

A new type of energy-density antenna is proposed for mobile telephony in the 800-1200-MHz range using a slot-monopole antenna (SMA) configuration. To mount the antenna on a mobile two orthogonally crossed slot antennas backed by a shallow cavity placed on the roof were found to be most suitable for receiving the magnetic field components, whereas a monopole attached to the base of the cavity and designed as a sleeve antenna is utilized to probe the electric field component. A prototype of the SMA system is manufactured, and its dimensions and design characteristics are presented. The radiation pattern, the input impedance of each of the three sections of the antenna system, and the isolation characteristics between all the sections of the SMA are measured and discussed.

Slot-monopole antenna system for energy-density reception at UHF

Telephone traffic in mobile radio communication system using dynamic frequency assignments

An analysis of traffic parameters for different types of users of land mobile radio (LMR) communications channels is presented. Based on audio monitoring of voice traffic, this analysis provides valuable information concerning efficiency of channel utilization by users; such information corroborates results already obtained through RF carrier monitoring. In addition, a user classification strategy, based on their message characteristics, is proposed and different procedures are suggested for estimating user message length when only base station information is available. Finally, the effects of grouping two users on the same channel are discussed from both channel allocation and grade of service points of view.

http://ieeexplore.ieee.org/iel5/25/34069/01623218.pdf

Traffic characterization and classification of users of land mobile communications channels

This article summarizes the ideas that are being actively discussed for use in mobile radio and, in particular, how they apply to the new 900-MHz region assigned to the Land Mobile Radio Services category. Over the next decade some of these methods will prove out and others will probably fall by the wayside. It is clear, however, that some new techniques will be necessary if mobile radio is to continue its growth.

H. Staras

Papers

Spectrum conservation in the Land Mobile Radio Services