History Of Mobile Phone
The history of mobile phones charts the development of devices which
connect wirelessly to the public switched telephone network. 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. Hand-held
radio transceivers have been available since the 1940s. Mobile telephones for
automobiles became available from some telephone companies in the 1940s. Early
devices were bulky and consumed high power and the network supported only a few
simultaneous conversations. Modern cellular networks allow automatic and
pervasive use of mobile phones for voice and data communications.
In the United States, engineers from Bell Labs began work on a system to
allow mobile users to place and receive telephone calls from automobiles,
leading to the inauguration of mobile service on June 17, 1946 in St. Louis,
Missouri. Shortly after, AT&T offered Mobile Telephone Service. A
wide range of mostly incompatible mobile telephone services offered limited
coverage area and only a few available channels in urban areas. The
introduction of cellular technology, which allowed re-use of frequencies many
times in small adjacent areas covered by relatively low powered transmitters,
made widespread adoption of mobile telephones economically feasible.
The advances in mobile telephony can be traced in successive generations
from the early "0G" services like MTS and its successor Improved
Mobile Telephone Service, to first generation (1G) analog cellular network,
second generation (2G) digital cellular networks, third generation (3G)
broadband data services to the current state of the art, fourth generation (4G)
native-IP networks.
Pioneers of mobile telephony
By 1930, telephone customers in the United States could be connected by
radio to a passenger on an ocean liner in the Atlantic Ocean. The service was
expensive, costing $7 per minute, equivalent to about $92.50/minute in 2011
dollars.
The first mobile telephone call was placed in St. Louis, Missouri on June
17, 1946 from a telephone set installed in an automobile. This first mobile
telephone call was the end result of more than 10 years of work by Bell Labs
scientists Alton Dickieson, D. Mitchell and H.I. Romnes.
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 on three different frequencies. 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.
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.
Handheld mobile phone
Prior to 1973, mobile telephony was limited to phones installed in cars and
other vehicles. Motorola and Bell Labs raced to be the first to produce a
handheld mobile phone. That race ended on April 3, 1973 when Martin Cooper, a Motorola
researcher and executive, made the first mobile telephone call from handheld
subscriber equipment, placing a call to Dr. Joel S. Engel of Bell Labs. The
prototype handheld phone used by Dr. Cooper weighed 2.5 pounds and measured
9 inches long, 5 inches deep and 1.75 inches wide. The prototype
offered a talk time of just 30 minutes and took 10 hours to re-charge. John F.
Mitchell, Motorola's chief of portable communication products and Cooper's boss
in 1973, played a key role in advancing the development of handheld mobile
telephone equipment. Mitchell successfully pushed Motorola to develop wireless
communication products that would be small enough to use anywhere and
participated in the design of the cellular phone.
