Federal Internet Law & Policy
An Educational Project
History :: Wireless / Radio :: Unlicensed
In the beginning, of course, all was unlicensed. And all was spread spectrum (in other words, early radios broadcasted all across the frequencies). [Spread Spectrum Scene] [FCC NOI 1981 ¶ 4]
And then came a cacophony of interference that led to the Federal Radio Commission and the licensing of all radio stations.
"In 1938, the Commission allowed devices employing relatively low level RF signals
to be operated without the need for individual licensing as long as their operation caused no
harmful interference to licensed services and the devices did not generate emissions or field strength levels greater than a specified level that was chosen to ensure that the device generally
would not cause interference.12 Typical kinds of equipment operated under these regulations
were wireless record players, carrier current communication systems (such as, campus radio
systems) and remote control devices."
"At the time the original unlicensed standards were adopted, most Part 15 RF devices were
designed to operate below 30 MHz and compliance with the field strength limit was relatively
easy to achieve. However, as the industry designed products intended for operation on higher
frequencies, it became more difficult to meet the field strength limit because the allowable field
strength level decreased as the operating frequency increased. Over the years the Commission
amended and expanded Part 15 of the rules to permit the non-licensed operation of devices at
higher field strengths in certain higher frequency bands in those cases where it could be
determined that the wide-spread use of such products would not result in harmful interference to
authorized radio services." [FCC UDELWG p 7]
Spread Spectrum technology had its origins, as with many technology innovations, in military necessity. The Nazi's were intercepting and jamming allied communications. [Ether's Ack-Ack] [Wenner] Hedy Lamarr and George Antheil, a music composer, wanted to provide a solution. They were looking specifically for a way of preventing the Nazi's from jamming Allied radio controlled torpedoes. If a radio transmission came over one frequency, the Nazi's could simply jam that frequency - the solution was to spread the transmission out over multiple frequencies, hopping about in a way that the Nazis could not anticipate and could not successfully jam. [FCC NOI 1981 ¶ 6 ("It was originally developed for military applications concerning covert communications and/or resistance to jamming.")]
Lamarr and Antheil were granted a US patent for "Secret Communication System" in 1942. [Spread Spectrum Scene]
"Patent 2,292,387: Secret Communication System
Hedy Kiesler Markey [Lamarr], Los Angeles, and George Antheil, Manhattan Beach, Calif.
Application June 10, 1941, Serial No. 397,412
This invention relates broadly to secret communication systems involving the use of carrier waves of different frequencies, and is especially useful in the remote control of dirigible craft, such as torpedoes.
An object of the invention is to provide a method of secret communication which is relatively simple and reliable in operation, but at the same time is difficult to discover or decipher.
Briefly, our system as adopted for radio control of a remote craft, employs a pair of synchronous records, one at the transmitting station and one at the receiving station, which change the tuning of the transmitting and receiving apparatus from time to time, so that without knowledge of the records an enemy would be unable to determine at what frequency a controlling impulse would be sent. Furthermore, we contemplate employing records of the type used for many years in player pianos, and which consist of long rolls of paper having perforations variously positioned in a plurality of longitudinal rows along the records. In a conventional player piano record there may be 88 rows of perforations, and in our system such a record would permit the use of 99 different carrier frequencies, from one to another of which both the transmitting and receiving station would be changed at intervals. Furthermore, records of the type described can be made of substantial length and may be driven slow or fast. This makes it possible for a pair of records, one at the transmitting station and one at the receiving station, to run for a length of time ample for remote control of a device such as a torpedo."
. . . . .
SECRET COMMUNICATION SYSTEM Markey et al.
Lamarr and Antheil turned their ideas over to the US Navy for development, where frequency hopping disappear for decades - part of the historical problem is that as much of this is military history, much of this is classified. Many histories note that the fruition of frequency hopping awaited the development of the transistor.
"In the 1950s, the Commission adopted new technical standards for devices such as radio
receivers and low power transmitters operating in the 27 MHz band and above 70 MHz." [FCC UDELWG p 8]
- 1957: Sylvania Electronics Systems initiates research into spread spectrum technology. [Inventors]
- 1959: Lamarr / Antheil patent expires [Inventors]
- 1962: Frequency Hopping Technology is used during cuban missile crisis for secure communications between blockading ships [Lamarr Foundation] [Inventors]
1960s through the 1980s, additional provisions were made under Part 15 to permit the operation
of equipment such as wireless microphones, telemetry systems, garage door openers, TV
interface devices (e.g., video cassette recorders), field disturbance sensors (e.g., anti-pilferage
systems for retail stores), auditory assistance devices, control and security alarm devices, and
cordless telephones." [FCC UDELWG p 8]
- 1973 Mid East War involved an "unexpected" amount of communications EW (jamming) resulting in DoD interest in solutions [Marcus]
- 1976 Robert C. Dixon, Spread Spectrum Systems (Wiley-Interscience) | Amazon 2nd Edition |
- 1978: Paul Newhouse, "Procedures for Analyzing Interference Caused by Spread-Spectrum Signals", IIT Research Institute, Report #ESD-TR-77-003, AD-A056911, February 1978
As information about spread spectrum became declassified, much research and literature about it was produced in the late 1970s, and private companies began to build toys. They ran into the rather significant problem that the operation of their spread spectrum civilian transmitters did not comport with FCC rules. Therefore these companies began to petition the FCC.[FCC NOI (Del Norte Technology)] The FCC issued several Special Temporary Authorities, waiving its rules, in order to spread spectrum research. [FCC NOI (AMRAD, Equitorial)]
A major policy objective of the FCC is the eliminating of radio interference. The mechanism for achieving this goal is traditionally the licensing frequencies. Spread spectrum permitted the FCC in the 1980s to experiment with an alternative solution to interference.
We are proposing in this Notice of Proposed Rulemaking rules that would authorize the use of spread spectrum under conditions that prevent harmful interference to other authorized users of the spectrum. We anticipate that this authorization will stimulate innovation in this technology, while meeting our statutory goal of controlling interference. - Notice of Proposed Rulemaking Dkt 81-413 (1984)
The FCC adopted Part 15 rules as a paradigm shift, carving out a piece of the spectrum landscape specifically for unlicensed use.
- 1980: Walter C Scales, Potential Use of Spread Spectrum Techniques in Non-Government Applications, MITRE (Dec. 1, 1980) (commissioned by the FCC)
- 1981 FCC Notice of Inquiry
- 1984: FCC Notice of Proposed Rulemaking
- FCC opens ISM to communications, permitting the first civil use of spread spectrum technologies.
- "In 1985, Commission first authorized the operation of non-licensed spread spectrum
systems in the 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz bands under Part 15 of
the rules at a power level of 1 W which was significantly higher than previously permitted
unlicensed use in other bands.13 Spread spectrum techniques, developed by the US military for
use during World War II, have high immunity to interference and low probability of intercept.
These same qualities make spread spectrum systems an attractive technology for consumer use.
The authorization of spread spectrum devices was significant for two reasons. First, the
Industrial, Scientific and Medical (ISM) bands at 902-928 MHz, 2400-2483.5 MHz and 5725-
5850 MHz are generally used for non-communications purposes so concerns about interference to primary services were small.14 Therefore, interference to other licensed and allocated services
was less of a concern and higher power could be allowed. Second, the ISM frequencies or
"unlicensed bands" provided sufficient bandwidth to permit the development of unlicensed
devices with high data rate capabilities." [FCC UDELWG p 8]
- Qualcomm incorporated
- IEEE establishes committee for 802.11
- the RLAN Telesystem ARLAN-SST is released to the market
- 1991: Conference: Spread Spectrum: Potential Commercial Applications Myth or Reality, May 21-23 Quebec
- FCC UNII Order, ET Docket 96-102, FCC 9705 (Released Jan 9, 1997) (FCC designates 300 MHz in the 5 GHz range for high speed data transmission under Part 15 unlicensed regime
- IEEE 802.11 approves standard
- EFF gives Hedy Lamarr a Pioneer Award
- FCC Order
- Wireless Ethernet Compatibility Alliance (Now WiFi Alliance) formed
- 802.11b (2.4GHz Band) ratified
- Apple builds WiFi into iBook computers
- 2000: 802.11a (5.8 GHz Band) ratified
- 2003: FCC Order additional spectrum for unlicensed
- 2004: FCC Ultrawideband Order
- The Ballet Mecanique
- Ether's Ack-Ack , TIME (Nov. 2, 1942) (discussing how United Nation's broadcasters would jump from one frequency to another in order to circumvent Axis jamming).
- Female Inventors: Hedy Lamarr (stating that Lamarr and Mandl would entertain Axis leaders including Hitler and Mussolini).
- FTC Report: Should Municipalities Provide Wireless Internet Service? Oct 2006
- George Antheil's Torpedo Patent, Paris Trans Atlantic Magazine (with picture of Antheil's punch paper roll)
- Hedy Lamarr Foundation :: From Strapless to Wireless
- Inventors Assistance League, Female Inventors, Hedy Lamarr
- M Marcus, Early Civil Spread Spectrum History
interview with pianist Guy Livingston on Hedy Lamarr's 'Secret Communication System' [Audio: Real Media & Windows Media]
- Walter C Scales, Potential Use of Spread Spectrum Techniques in Non-Government Applications, MITRE (Dec. 1, 1980)
- Schilling, D.L.; Pickholtz, R.L.; Milstein, L.B., Spread spectrum goes commercial,
Volume 27, Issue 8, Aug 1990 Page(s):40 - 41, 44-5
- Spread Spectrum Scene,
- Kenneth Carter, Ahmed Lahjouji, Neal McNeal, Unlicensed and Unshackled: A Joint OSP-OET White Paper on Unlicensed Devices and Their Regulatory Issues, OSP Working Paper 39 (May 2004)
- Melinda Wenner, Hedy Lamarr, Not just a pretty face, Scientific American (June 3, 2008)