Unlicensed to Kill: A Brief History of the FCC's Part 15 Rules

Abstract

For nearly a century, lawyers and engineers have struggled to make workable behavioral rules for the complicated and, literally, ethereal problem of radio spectrum interference and its negative impact on value of the spectrum resource to all. One counter current has been the Federal Communications Commission's rules governing unlicensed operation. For 70 years, these rules have, with increasing success, achieved a balance among stability, flexibility, and development. The rules permit radio operation on a sufferance basis in broad swaths of the radio spectrum this is not allocated specifically to unlicensed use. In 1938, then-FCC Chief Engineer, Ewell Jett argued that argued if certain RF emissions which were sufficiently weak and short ranged so as to not be considered measurable, and would therefore, not rise to the level of harmful interference. The FCC set about to promulgate rules to manage such devices based on this jurisprudence.

While the unlicensed rules may lack a glorious and romantic past, licensed operation holds great interest for spectrum policy wonks as well as rich issues for in the spectrum policy debate. Much of the policy debate in last decade has been couched in terms of how spectrum rights are defined. The regulatory change since the early part of this decade has been a deliberate review of policy options, fuelled by theoretical economics and multidisciplinary research.

Nonetheless, the origin and evolution of unlicensed rules has eschewed such an esoteric discussion. Rather, the rules concentrate on the effective power and modulation characteristic of the radio devices themselves. When the services offered by wireless communications are not well defined or are not knowable at the time rules are created (and they never are), an unlicensed regime holds certain advantages, such as competition, product innovation, and user investment in wireless networks.

Since unlicensed devices have historically represented a smaller part of radio services and given the richness of the current debate, an understanding of the history development of the rules can serve to inform the future. The rules have been effective due to the fact they focus on fundamental property: irradiated power which is the direct cause of harmful interference. The rules establish parameters not standards and market forces are free to operate within these constraints.

In sum, the jurisprudence underlying the rules is that unlicensed spectrum is not spectrum at all. Perhaps this is the next great idea for all spectrum policy: Spectrum does not really exist. It is merely an idea - a concept - a way of describing and organizing the physical world in our minds and in our actions. Spectrum is a legal and engineering construct to control for an immutable fundamental physical property. When multiple electromagnetic waves, used as carrier waves to transmit information are incident in time, harmonic in frequency, and alight on the same reception antenna, they degrade one another's ability to transmit information. If we can accept that spectrum does not exist, then perhaps we can free ourselves from a century of thinking and search for more modern, more nibble solutions. More flexible modes of regulation might focus on dealing with interference, not necessarily avoiding it, and coordinating uses.

Keywords: Unlicensed, Spectrum, Federal Communications Commission, Part 15, Wi-Fi