Radio technology and spectrum policy both were developed in the early 20th century when frequencies were much lower and wavelengths much longer than options available today. The smaller wavelengths in SHF and EHF enable antenna approach unimaginable when international and national spectrum polices were first framed. Combined with MIMO-like multielement antenna technology, these antenna approaches can be used to control intersystem and interservice interference to enable novel spectrum sharing approaches that have no analogs in lower bands.

[...] This paper explores how spectrum policy and spectrum technologies can evolve to enable sharing among different stakeholders in the above 100 GHz spectrum, without introducing harmful interference or disrupting either security applications or fundamental science exploration. This portion of the spectrum presents new opportunities to design spectrum sharing schemes, based on novel antenna designs, directional ultra-high-rate communications, and active/passive user coordination. The paper provides a tutorial on current regulations above 100 GHz, and highlights how sharing is central to allowing each stakeholder to make the most out of this spectrum. It then defines - through detailed simulations based on standard International Telecommunications Union (ITU) channel and antenna models - scenarios in which active users may introduce harmful interference to passive sensing. Based on this evaluation, it reviews a number of promising techniques that can enable active/passive sharing above 100 GHz. The critical review and tutorial on policy and technologies of this paper have the potential to kickstart future research and regulations that promote safe coexistence between active and passive users above 100 GHz, further benefiting the development of digital technologies and scientific exploration.

In the June 2005 issue of this magazine, a previous article on the spectrum management implications of millimeter-wave (mm-wave) propagation was published [1] . It was derived from a Federal Communications Commission report issued in 1997.

Most wireless technology researchers view obtaining access to spectrum as a specialty for others who focus solely in spectrum policy. Thus, the researcher finds out from others what bands are available for their application. In many cases, the question of whether band x can be used for application $y$ ultimately depends on whether this application in this band will cause interference to...

On April 21, 2022, the U.S. national spectrum regulator for the private sector, the Federal Communications Commission/FCC, formally asked for input on the issue of “the role of receiver performance in (its) spectrum management responsibilities” [1]. A previous issue of this column addressed related issues and the enigmatic question “Which uses the most spectrum: transmitters or receivers?” [2]. That issue described the classic example of early U.S. market UHF TV receivers in the 1950s when UHF technology was first being introduced to consumer electronics. FCC decided at the time that the selectivity and intermodulation issues in consumer grade receivers would limit the use of UHF TV channels to channels spaced six channels apart to avoid interference [3]. Thus, only 1/6 of the apparent number of UHF channels could be used in a given city even if there were no other cities nearby. (With improved electronics and digital television modulation, television channels can now be used with a much higher density.)

This chapter describes the framework for the use of spectrum by THz communications, which has to rely on the possibility to share the spectrum with passive service such as Earth Exploration-Satellite Service (EESS) and radio astronomy (RA). First, an introduction of the structure of the international and national policies is given taking into account spectrum beyond 50 GHz. The methods and procedures for sharing studies with passive services are described. This includes both the studies, which have been performed during the preparation of World Radiocommunication Conference (WRC) 2019 and novel concepts for future enhanced sharing studies. The chapter concludes with the details of the spectrum regulation for frequencies beyond 252 GHz based on the results of WRC 2019.

As 5G rollout is underway in many countries, R&D is also underway on its successor 6G and along with deliberations in International Telecommunication Union - Radiocommunication Standardization Sector (ITU-R) Working Party 5D (WP 5D) [1]. 6G will likely use both the existing approximately 50 5G frequency bands that range from 617 MHz to 48.2 GHz, not all of which are available in every country, as well as possible new bands above 100 GHz that have no commercial use at this time [2]. The bands above 100 GHz are attractive for high communications bit rate links because they potentially offer much greater bandwidths than the maximum 400 MHz contiguous bandwidth in any of the existing 5G bands. While bonding nonadjacent bands together for high bit rates has been done at lower bands, it is unclear yet whether this is practical for bandwidths greater than 400 MHz at frequencies above 100 GHz where there are large blocks of unused spectrum at present.

Afrustrating aspect of spectrum policy is the fact that in virtually every band one looks at, in most locations one finds spectrum that appears to be underutilized. (Admittedly this is complicated by the fact that there is no general consensus on how to quantify spectrum utilization.) There are many reasons for this apparent underutilization, including uneven terrain and nonuniform spatial distribution of needs for spectrum access. But a major factor concerns spectrum uses with high societal and economic value, with large peak-to-average usage ratios and society placing a very high value on requiring that certain of these uses must have immediate access to spectrum when they need it. With traditional spectrum policies this requires dedicated spectrum. Such highly societal value uses include public safety communications and military communications.

Discusses spectrum policy issues that impact 5G mobile communications. The issue that stimulated all this activity is the creation of one of several new cellular bands for fifth generation (5G). The band under consideration near 24 GHz is close to a band that is used by passive satellite sensors to detect water vapor, and there are concerns that out-of-band-emissions from 5G base stations and/or m...

While the International Telecommunication Union (ITU) Table of International Allocations and most national allocations tables have listed spectrum allocations up to 275 GHz, in reality specific policies for technologies above 100 GHz have been very rare until recently. Both Conference of European Postal & Telecommunications (CEPT)/ERC, the group of European spectrum regulators, and the Japanese regulator MIC have had some specific provisions for this spectrum region. On March 15, 2019 the U.S. spectrum regulator FCC made a decision for this spectrum that opens a variety of new opportunities for use of this spectrum.

Reports on spectrum management policy development and discussions that took place at the nternational Telecommunication Union’s (ITU) World Radiocommunication Conference 2019 (WRC-19) that was held in Sharm el-Sheikh, Egypt, from 28 October to 22 November 2019.

A few decades ago, antennas were almost unnoticed in the urban and suburban landscape, except for home television receive antennas. At that time, such areas had a few AM, FM, and television broadcast antennas that were sometimes collocated (although less so in the United States) and served wide areas. The low-capacity land mobile radio systems that existed then also used antennas sited on relatively few high towers or building sites, covering large areas but with little total capacity compared to today’s cellular systems.

Spectrum policy has to deal with both operational use of spectrum-based systems as well as experiments to develop innovative technologies both to improve present uses or for entirely new uses. For example, two decades ago use of > 30 GHz millimeter-wave spectrum for mobile communications would have seemed ludicrous to most practitioners, but today it is a major component of the pending fifth generation (5G) wireless systems. Different countries have different ways of dealing with authorizing experimental use of spectrum to advance both wireless communications and other spectrum uses. This column reviews the approaches used in several countries. The U.S. Federal Communications Commission (FCC) issues about 2000 experimental licenses a year. In 2010–2016, the FCC reviewed and updated its provisions for experimental licensing in Docket 10-236.1