History of Mobile Phones

In December 1947, Douglas H. Ring and W. Rae Young, Bell Labs engineers, proposed hexagonal cells for mobile phones.Philip T. Porter, also of Bell Labs, proposed that the cell towers be at the corners of the hexagons rather than the centers and have directional antennas that would transmit/receive in 3 directions (see picture at left) into 3 adjacent hexagon cells.The technology did not exist then and the frequencies had not yet been allocated. Cellular technology was undeveloped until the 1960s, when Richard H. Frenkiel and Joel S. Engel of Bell Labs developed the electronics. In Europe, radio telephony was first used on the first-class passenger trains between Berlin and Hamburg in 1926.At the same time, radio telephony was introduced on passenger airplanes for air traffic security. Later radio telephony was introduced on a large scale in German tanks during the Second World War. After the war German police in the British zone of occupation first used disused tank telephony equipment to run the first radio patrol cars.In all of these cases the service was confined to specialists that were trained to use the equipment. In the early 1950s ships on the Rhine were

among the first to use radio telephony with an untrained end customer as a user. Recognizable mobile phones with direct dialing have existed at least since the 1950s. In the 1954 movie Sabrina, the businessman Linus Larrabee (played by Humphrey Bogart) makes a call from the phone in the back of his limousine. The first fully automatic mobile phone system, called MTA (Mobile Telephone system A), was developed by Ericsson and commercially released in Sweden in 1956. This was the first system that didn't require any kind of manual control, but had the disadvantage of a phone weight of 40 kg (90 lb). MTB, an upgraded version with transistors, weighing 9 kg (20 lb), was introduced in 1965 and used dual-tone multi-frequency signaling. It had 150 customers in the beginning and 600 when it shut down in 1983. In 1967, each mobile phone had to stay within the cell area serviced by one base station throughout the phone call. This did not provide continuity of automatic telephone service to mobile phones moving through several cell areas. In 1970 Amos E. Joel, Jr., another Bell Labs engineer,invented an automatic "call handoff" system to allow mobile phones to move through several cell areas during a single conversation without loss of conversation.

On April 3, 1973, Motorola employee Dr. Martin Cooper placed a call to rival Joel Engel, head of research at AT&T's Bell Labs, while walking the streets of New York City talking on the first Motorola DynaTAC prototype. Motorola has a long history of making automotive radio, especially two-way radios for taxicabs and police cruisers. In 1978, Bell Labs launched a trial of first commercial cellular network in Chicago using AMPS

The first handheld mobile phone to become commercially available to the US market was the Motorola DynaTAC 8000X, which received approval in 1983. Mobile phones began to proliferate through the 1980s with the introduction of "cellular" phones based on cellular networks with multiple base stations located relatively close to each other, and protocols for the automated "handover" between two cells when a phone moved from one cell to the other. At this time analog transmission was in use in all systems. Mobile phones were somewhat larger than current ones, and at first, all were designed for permanent installation in vehicles (hence the term car phone). Soon, some of these bulky units were converted for use as "transportable" phones the size of a briefcase. Motorola introduced the first truly portable, handheld phone. These systems (NMT, AMPS, TACS, RTMI, C-Netz, and Radiocom 2000) later became known as first generation (1G) mobile phones.