1985

FCC Approves Unlicensed Spread Spectrum

Michael J. Marcus (b. 1946)

The wireless spectrum is divided into different bands, each with its own physical properties and regulatory rules. In the 1970s, transmitting with a radio in most bands required getting licensed by the government. The unfortunate exception was citizens band (CB) radio, which was virtually unusable because it was so crowded.

Then, in 1981, an engineer at the US Federal Communications Commission (FCC) started an official notice of inquiry to explore using a portion of the radio frequency (RF) spectrum for spread spectrum communications. The engineer, Michael J. Marcus, doggedly pursued the idea for four years at the FCC. His vision was to legalize the use of spread spectrum technology, an approach developed during World War II to hide wireless communications from enemy monitoring and jamming, to allow for research and the development of civilian spread spectrum systems.

But making unlicensed spectrum available proved controversial with incumbent manufacturers and wireless users. In the end, Marcus won his rulemaking on May 9, 1985, but the use of spread spectrum was largely limited to so-called industrial, scientific, and medical (ISM) bands at 900 megahertz, 2.4 gigahertz, and 5.7 gigahertz. Because that band was also used by commercial equipment such as microwave ovens and radar systems, there was too much interference to make it usable for other applications.

Still, the genie was out of the bottle. In March 1991, the NCR Corporation® started selling a wireless network product called WaveLAN that provided 2 megabits per second over the unlicensed 900-megahertz band. The technology proved popular, leading to the development of the 802.11 Wireless LAN Working Committee. The industry created the Wi-Fi Alliance in 1999, licensing the Wi-Fi® trademark and logo to products that passed an interoperability test. While the original Wi-Fi systems could stream data at a maximum of 2 megabits per second, equipment implementing the standard approved in December 2013 can go as fast as 866.7 megabits per second.

The wireless spectrum, which once required a license from the government for use, began opening up to the public in 1985.