Cellular telephony is an exceptional technological achievement that has enabled us to communicate from virtually any location and access a myriad of information at the touch of a button. The device connects people, provides security, and bridges informational gaps in modern society. Martin Cooper, Joel S. Engel, Richard H. Frenkiel, Thomas Haug, and Yoshihisa Okumura each made substantial contributions to its creation.
The first limited form of mobile telephone service was provided by AT&T in 1946, and the initial ideas for cellular systems emerged at Bell Labs a year later. A lack of channels inhibited further exploration of these ideas until the late 1960s, when Bell Labs began planning activities for a "high capacity" mobile telephone system. Engel and Frenkiel, with the late Phil Porter, were the earliest engineers involved in this work. They developed a plan for a network of low-power transmitters and receivers spread throughout a region in small coverage areas that came to be called cells, which allowed service to be expanded to millions of users with a limited number of channels. This plan resulted in technical report that was filed with the U.S. Federal Communications Commission in 1971 presenting the design for what would become the Advanced Mobile Phone System (AMPS), the first cellular telephone system in the U.S.
At the same time while working at Nippon Telegraph and Telephone (NTT) Research Laboratories, Yoshihisa Okumura was laying the groundwork for a network system for simultaneous cell phone use by the masses in Japan. Through the investigation of precise propagation of radio waves in a high frequency range, Okumura found data that provided the foundation for a mobile model that could be used over wide areas that included urban cities, hills, and mountains. In 1979, the NTT’s network became the world’s first fully integrated commercial cell phone system and had the most advanced electronic switching.
Shortly after the cellular network was developed, Martin Cooper, who was working at Motorola at the time, unveiled the first portable hand-held cellular phone. After conducting in-depth research and filing several patents on technologies needed for the device, Cooper and his team produced a fully functional phone that utilized radio waves and frequency reuse to enable mobility and operability over a wide area. In 1973, Cooper made the first mobile telephone call on his cell phone prototype from a New York City street to a landline phone at Bell Laboratories. The phone call was answered by Engel.
By 1960 several Nordic countries had their own local mobile systems, however, cell phone users were not able to transfer calls between towers. From 1970 to 1982, Thomas Haug worked to develop the Nordic Mobile Telephony (NMT) system, which provided analog service across the various countries. In 1982, inspired by the successful Nordic example, Haug formed a research group to create a system that would allow users to place and receive calls anywhere in the world. By 1992 Haug and his colleagues had successfully developed the new digital high-quality and high-security mobile communication system called Global System for Mobile Communications (GSM), which permitted users to freely move in and between any countries where the system was installed while setting up and receiving calls automatically.