Development of Cell Phones
The development of cell phones started at the turn of the century and has its roots in radio communication. In fact the line between radio and cell-phone communication is finer than you might think. Cell phones are also much older than many people realize. Cell-phone-like mobile devices saw action in World War II and the Cold War. Cell phones have a long and rich history that began at the turn of the 20th century.
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Mobile Radio Phones
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While true cell-phones were developed in the late 1950s, their ancestors, radio phones, were invented in the 1920s in Germany. These radio phones were used by trained operators for emergency communication on trains and passenger aircraft. One of the first major uses of radio phones was as communication equipment for Nazi tanks during World War II. In 1946, Soviet engineers designed a radio phone that could connect to a phone network, provided that the operator was within 20 kilometers of a phone line. The first radio phone designed for an untrained user was installed on ships sailing the Rhine in the early 1950s.
The First Cell-Phone
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The first man-portable mobile phone was the LK-1 developed in 1957 by Leonid Kupriyanovich a Soviet engineer. The LK-1 was a rotary dial phone that transmitted a radio signal to a base station that connected to the phone network via landline. This base station could service several customers at once, and became the archetype for mobile phone communication around the world until the development of cellular phones.
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Modern Cell Development
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As radio phones began to see more use, the limitations became increasingly apparent. In 1947, Douglas Ring and W. Rae Young of Bell Laboratories proposed a method of separating mobile phone coverage into hexagonal "cells" using towers. The idea was further improved by Philip T. Porter who was also working for bell at the time. Porter proposed that the towers be placed at the corners of the cells and that the towers transmit signal in three directions. While this is the setup that is used today, the technology required did not exist at the time. Cell phone technology would not be developed until the 1960s.
Call Hand-off
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In 1967, a person using a cell phone would have to stay within the cell they started their call in or else it would be lost, as cellular technology was unable to carry a call over to another cell at the time. This changed in 1970 when Amos Joel Jr. invented an automatic "call hand-off" system that allowed for cell phone users to pass through many cells with out having a lost call.
Cell phones and the FCC
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In 1971, AT&T submitted a request to the FFC for dedicated frequencies for cell phones. After a long period of debate and deliberation, the FFC allotted 824 to 894 MHz band exclusive cell phone use in 1982. This was known as the Advanced Mobile Phone System AMPS. Just eight years later, AMPS was superseded by Digital AMPS for use with second generation phones. This completed the development of the modern cell phone, and opened up the large world of the cell technology today.
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References
- Photo Credit Cell phone image by Elzbieta Sekowska from Fotolia.com
