The history of mobile phones charts the development of devices which connect wirelessly to the public switched telephone network. Early devices were bulky and consumed high power and the network supported only a few simultaneous conversations. Modern cellular networks and microprocessor control systems allow automatic and pervasive use of mobile phones for voice and data communications.
The transmission of speech by radio has a long and varied history going back to Reginald Fessenden's invention and shore-to-ship demonstration of radio telephony, through the Second World War with military use of radio telephony links. Mobile telephones for automobiles became available from some telephone companies in the 1950s. Hand-held radio transceivers have been available since the Second World War.
Mobile phone history is often divided into generations (first, second, third and so on) to mark significant step changes in capabilities as the technology improved.
Pioneers of radio telephony
By 1930, telephone customers in the United States could place a call to a passenger on a liner in the Atlantic Ocean. Air time charges were quite high, at $7(1930)/minute (about $92.50/minute in 2011 dollars). In areas with Marine VHF radio and a shore station, it is still possible to arrange a call from the public telephone network to a ship, still using manual call set-up and the services of a human marine radio operator.
However it was the 1940s onwards that saw the seeds of technological development which would eventually produce the mobile phone that we know today. Motorola developed a backpacked two-way radio, the Walkie-Talkie and a large hand-held two-way radio for the US military. This battery powered "Handie-Talkie" (HT) was about the size of a man's forearm.
In 1946 in St. Louis, the Mobile Telephone Service was introduced. Only three radio channels were available, and call set-up required manual operation by a mobile operator. Although very popular and commercially successful, the service was limited by having only a few voice channels per district.
In 1964 Improved Mobile Telephone Service was introduced with additional channels and more automatic handling of calls to the public switched telephone network. Even the addition of radio channels in three bands was insufficient to meet demand for vehicle-mounted mobile radio systems.
In 1969, a patent for a wireless phone using an acoustic coupler for incoming calls was issued in US Patent Number 3,449,750 to George Sweigert of Euclid, Ohio on June 10, 1969, but did not include dialing a number for outgoing calls.
Cellular concepts
In December 1947, Douglas H. Ring and W. Rae Young, Bell Labs engineers, proposed hexagonal cells for mobile phones in vehicles. 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 three directions (see picture at right) into three adjacent hexagon cells. At this stage, the technology to implement these ideas did not exist, nor had the frequencies been allocated. Several years would pass before Richard H. Frenkiel and Joel S. Engel of Bell Labs developed the electronics to achieve this in the 1960s.
In all these early examples, a mobile phone had to stay within the coverage area serviced by one base station throughout the phone call, i.e. there was no continuity of service as the phones moved through several cell areas. The concepts of frequency reuse and handoff, as well as a number of other concepts that formed the basis of modern cell phone technology, were described in the 1970s. In 1970 Amos E. Joel, Jr., a Bell Labs engineer, invented an automatic "call handoff" system to allow mobile phones to move through several cell areas during a single conversation without interruption.
In 1969 Amtrak equipped commuter trains along the 225-mile New York-Washington route with special pay phones that allowed passengers to place telephone calls while the train was moving. The system re-used six frequencies in the 450 MHZ band in nine sites, a precursor of the concept later applied in cellular telephones.
In December 1971, AT&T submitted a proposal for cellular service to the Federal Communications Commission (FCC). After years of hearings, the FCC approved the proposal in 1982 for Advanced Mobile Phone System (AMPS) and allocated frequencies in the 824–894 MHz band. Analog AMPS was eventually superseded by Digital AMPS in 1990.
A cellular telephone switching plan was described by Fluhr and Nussbaum in 1973, and a cellular telephone data signaling system was described in 1977 by Hachenburg et al. In 1979 a U.S. Patent 4,152,647 was issued to Charles A. Gladden and Martin H. Parelman, of Las Vegas for an emergency cellular system for rapid deployment in areas where there was no cellular service.
Before cellular networks
Mobile radio telephone systems preceded modern cellular mobile telephony technology. Since they were the predecessors of the first generation of cellular telephones, these systems are sometimes retroactively referred to as pre cellular (or sometimes zero generation) systems. Technologies used in pre cellular systems included the Push to Talk (PTT or manual), Mobile Telephone System (MTS), Improved Mobile Telephone Service (IMTS), and Advanced Mobile Telephone System (AMTS) systems. These early mobile telephone systems can be distinguished from earlier closed radiotelephone systems in that they were available as a commercial service that was part of the public switched telephone network, with their own telephone numbers, rather than part of a closed network such as a police radio or taxi dispatch system.
These mobile telephones were usually mounted in cars or trucks, though briefcase models were also made. Typically, the transceiver (transmitter-receiver) was mounted in the vehicle trunk and attached to the "head" (dial, display, and handset) mounted near the driver seat.
They were sold through WCCs (Wireline Common Carriers, AKA telephone companies), RCCs (Radio Common Carriers), and two-way radio dealers.
Radio Common Carrier
Parallel to Improved Mobile Telephone Service (IMTS) in the US until the rollout of cellular AMPS systems, a competing mobile telephone technology was called Radio Common Carrier or RCC. The service was provided from the 1960s until the 1980s when cellular AMPS systems made RCC equipment obsolete. These systems operated in a regulated environment in competition with the Bell System's MTS and IMTS. RCCs handled telephone calls and were operated by private companies and individuals. Some systems were designed to allow customers of adjacent RCCs to use their facilities but the universe of RCCs did not comply with any single interoperable technical standard (a capability called roaming in modern systems). For example, the phone of an Omaha, Nebraska–based RCC service would not be likely to work in Phoenix, Arizona. At the end of RCC's existence, industry associations were working on a technical standard that would potentially have allowed roaming, and some mobile users had multiple decoders to enable operation with more than one of the common signaling formats (600/1500, 2805, and Reach). Manual operation was often a fallback for RCC roamers.
Roaming was not encouraged, in part, because there was no centralized industry billing database for RCCs. Signaling formats were not standardized. For example, some systems used two-tone sequential paging to alert a mobile or hand-held that a wired phone was trying to call them. Other systems used DTMF. Some used a system called Secode 2805 which transmitted an interrupted 2805 Hz tone (in a manner similar to IMTS signaling) to alert mobiles of an offered call. Some radio equipment used with RCC systems was half-duplex, push-to-talk equipment such as Motorola hand-helds or RCA 700-series conventional two-way radios. Other vehicular equipment had telephone handsets, rotary or pushbutton dials, and operated full duplex like a conventional wired telephone. A few users had full-duplex briefcase telephones (radically advanced for their day).
RCCs used paired UHF 454/459 MHz and VHF 152/158 MHz frequencies near those used by IMTS.
Emergence of commercial mobile phone services
Alongside the early developments outlined above, a different technology was also growing in popularity. Two-way mobile radios (known as mobile rigs) were used in vehicles such as taxicabs, police cruisers, and ambulances, but were not mobile phones, because they were not connected to the telephone network.
The first fully automated mobile phone system for vehicles was launched in Sweden in 1960. Named MTA (Mobile Telephone system A), it allowed calls to be made and received in the car using a rotary dial. The car phone could also be paged. Calls from the car were direct dial, whereas incoming calls required an operator to determine which base station the phone was currently at. It was developed by Sture Laurén and other engineers at Televerket network operator. Ericsson provided the switchboard while Svenska Radioaktiebolaget (SRA) and Marconi provided the telephones and base station equipment. MTA phones consisted of vacuum tubes and relays, and weighed 40 kg. In 1962, an upgraded version called Mobile System B (MTB) was introduced. This was a push-button telephone, and used transistors and DTMF signaling to improve its operational reliability. In 1971 the MTD version was launched, opening for several different brands of equipment and gaining commercial success. The network remained open until 1983 and still had 600 customers when it closed.
In 1958 development began on a similar system for motorists in the USSR. The "Altay" national civil mobile phone service was based on Soviet MRT-1327 standard. The main developers of the Altay system were the Voronezh Science Research Institute of Communications (VNIIS) and the State Specialized Project Institute (GSPI). In 1963 the service started in Moscow, and by 1970 was deployed in 30 cities across the USSR. Versions of the Altay system are still in use today as a trunking system in some parts of Russia.
In 1959 a private telephone company located in Brewster, Kansas, USA, the S&T Telephone Company, (still in business today) with the use of Motorola Radio Telephone equipment and a private tower facility, offered to the public mobile telephone services in that local area of NW Kansas. This system was a direct dial up service through their local switchboard, and was installed in many private vehicles including grain combines, trucks, and automobiles. For some as yet unknown reason, the system, after being placed online and operated for a very brief time period, was shut down. The management of the company was immediately changed, and the fully operable system and related equipment was immediately dismantled in early 1960, not to be seen again.
In 1966, Bulgaria presented the pocket mobile automatic phone RAT-0,5 combined with a base station RATZ-10 (RATC-10) on Interorgtechnika-66 international exhibition. One base station, connected to one telephone wire line, could serve up to six customers.
One of the first successful public commercial mobile phone networks was the ARP network in Finland, launched in 1971. Posthumously, ARP is sometimes viewed as a zero generation (0G) cellular network, being slightly above previous proprietary and limited coverage networks.
