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18.1. History
Wireless
LANs are based on spread spectrum technology, initially developed for
military communications by the U.S. Army during World War II.
Military technicians considered spread spectrum desirable because it
was more resistant to jamming. Other advances at this time allowed an
increase in the radio data rate. After 1945, commercial enterprises
began to expand on this technology, realizing its potential benefits
to consumers.Spread
spectrum technology evolved into the beginnings of the modern
wireless LAN in 1971 with a University of Hawaii project called
AlohNet. This project allowed seven computers around the various
islands to communicate bidirectionally with a central hub on Oahu.The
university research on AlohNet paved the way for the first generation
of modern wireless networking gear, which operated at the 901-928 MHz
frequency range. Primarily used by the military, this phase of
wireless development saw only limited consumer use, due to crowding
within this frequency and the relatively low speed.From this point, the 2.4 GHz frequency
was defined for unlicensed use, so wireless technology began to
emerge in this range and the 802.11 specification was established.
This specification evolved into the widely accepted 802.11b standard,
and continues to evolve into faster, more secure implementations of
the technology.
