Spectrum management
Spectrum management is the process of regulating the use of radio frequencies to promote efficient use and gain a net social benefit. The term radio spectrum typically refers to the full frequency range from 1 Hz to 3000 GHz that may be used for wireless communication. Increasing demand for services such as mobile telephones and many others has required changes in the philosophy of spectrum management. Demand for wireless broadband has soared due to technological innovation, such as 3G and 4G mobile services, and the rapid expansion of wireless internet services.
Since the 1930s, spectrum was assigned through administrative licensing. Limited by technology, signal interference was once considered as a major problem of spectrum use. Therefore, exclusive licensing was established to protect licensees' signals. This former practice of discrete bands licensed to groups of similar services is giving way, in many countries, to a "spectrum auction" model that is intended to speed technological innovation and improve the efficiency of spectrum use. During the experimental process of spectrum assignment, other approaches have also been carried out, namely, lotteries, unlicensed access, and privatization of spectrum.
Most recently, America has been moving toward a shared spectrum policy, whereas Europe has been pursuing an authorized shared access licensing model. President Obama made shared spectrum the policy of the United States on 14 June 2013, following recommendations from the President's Council of Advisors for Science and Technology which advocated the sharing of federal radio spectrum when unused at a place and time provided it does not pose undue risks. In line with this guidance, as of Dec 2014 the FCC was extending the limited success of television band spectrum sharing into other bands, significantly into the 3550–3700 MHz US Navy radar band via a three tier licensing model.
Governments and spectrum management
Most countries consider RF spectrum as an exclusive property of the state. The RF spectrum is a national resource, much like water, land, gas and minerals. Unlike these, however, RF is reusable. The purpose of spectrum management is to mitigate radio spectrum pollution, and maximize the benefit of usable radio spectrum.The first sentence of the International Telecommunication Union constitution fully recognises "the sovereign right of each State to regulate its telecommunication". Effective spectrum management requires regulation at national, regional, and global levels.
Goals of spectrum management include: rationalize and optimize the use of the RF spectrum; avoid and solve interference; design short and long range frequency allocations; advance the introduction of new wireless technologies; coordinate wireless communications with neighbours and other administrations. Radio spectrum items which need to be nationally regulated: frequency allocation for various radio services, assignment of license and RF to transmitting stations, type approval of equipment, fee collection, notifying ITU for the Master International Frequency Register, coordination with neighbour countries, external relations toward regional commissions and toward ITU.
Spectrum use
Spectrum management is a growing problem due to the growing number of spectrum uses. Uses include: over-the-air broadcasting, ; government and research uses ; commercial services to the public ; and industrial, scientific and medical services.In the 1980s, the only concern was about radio and television broadcasting; but today mobile phones and wireless computer networks are more and more important as fewer than 15% of US households rely on over-the-air broadcasting to receive their TV signals.
The US spectrum is managed either by the Federal Communications Commission for non-governmental applications or by the National Telecommunications and Information Administration for governmental applications. For shared application, both entities should agree.
The spectrum is divided into different frequency bands, each having a specific application. For instance, the frequency band that covers 300 kHz to 535 kHz is reserved for aeronautical and maritime communications and the spectrum from 520 kHz to 1700 kHz for AM radio. This process is called "allocation".
The next step is to assign frequencies to specific users or classes of users. Each frequency band has a specific assignment that depends on the nature of the application and the numbers of users. Indeed, some applications require a wider band than others. In addition, "guard bands" are needed to keep the interference between applications to a minimum.
Status quo: the command and control approach
The Command and Control management approach is the one currently employed by most regulators around the globe. This approach advocates that the regulators be the centralized authorities for spectrum allocation and usage decisions. In the US example, the regulator determines the use cases for specified spectrum portions, as well as the parties who will have access to them.The Federal Communications Commission also regulates the physical layer technologies to be employed.
The allocation decisions are often static in temporal and spatial dimensions, meaning that they are valid for extended periods of time and for large geographical regions. The usage is often set to be exclusive; each band is dedicated to a single provider, thus maintaining interference free communication. The command and control management model dates back to initial days of wireless communications, when the technologies employed required interference-free mediums for achieving acceptable quality. Thus, it is often argued that the exclusive nature of the command and control approach is an artifact of outdated technologies.
The apparent advantages of this model is that services related to public interest could be sustained. In terms of profitability, public interest programs, for example, over-the-air television, may not be as attractive as commercial ones in the provider perspective, but they are nevertheless beneficial for the society. Therefore, these services are often implicitly enforced by the regulator through the license agreements. Another advantage is the standardization that results from such a centralized approach. Such standardization is critical in networked industries, for which the telecommunication industry is a text-book example. One scholar has published a paper that shows how the development of new technologies promises to bring considerably more spectrum to the public, but would require that society embrace a new paradigm of spectrum use.
GAO Report on Spectrum Management (2004)
Excerpt:Alternative spectrum governance regimes and the spectrum debate
With the digital transition, spectrum management entered a new age. Full conversion to digital TV by 17 February 2009 allows broadcasters to use spectrum more efficiently and save space for the possibility of sharing spectrum.Spectrum sharing is the subject of heated discussion. Exponential growth of commercial wireless calls for additional spectrum to accommodate more traffic. As a regulator, the FCC responded to these needs by making more spectrum available. A secondary market has been allowed to emerge and licensees are encouraged to lease use of the spectrum to third parties temporarily. Making licenses transferable is an important attempt by the FCC to create incentives for broadcasters to share unused spectrum. Another proposed solution to the spectrum scarcity problem is to enable communications systems to occupy spectrum that was previously allocated for radar use and to cooperatively share spectrum. This approach has received increased attention recently with several research programs, including DARPA projects, investigating several methods of cooperative radar-communications spectrum sharing. More alternatives are underway such as spectrum sharing in cellular networks.
Spectrum scarcity has emerged as a primary problem encountered when trying to launch new wireless services. The effects of this scarcity are most noticeable in spectrum auctions where the operators often need to invest billions of dollars to secure access to specified bands in the available spectrum.
In spite of this scarcity, recent spectrum utilization measurements have shown that the available spectrum opportunities are severely underutilized, i.e. left unused. This artificial "access limitation"-based scarcity is often considered to result from the static and rigid nature of the command and control governance regime. Interested parties have started to consider possible improvements in the governance regime by relaxing the constraints on spectrum access. Two prevailing models are the "spectrum commons" and the "spectrum property rights" approaches.
Spectrum commons theory
Under US law, the spectrum is not considered to be the property of the private sector nor of the government except insofar as the term "government" is used to be synonymous with "the people".The original use of the term "the commons" was the practice by which the public at large had limited rights to use the commons; each person then had an interest in their own usage rights, but the commons themselves were not property, nor were the rights "property" since they could not be traded. The term "tragedy of the commons" was popularized by Garrett Hardin in a 1968 article which appeared in Science. The tragedy of the commons illustrates the philosophy that destructive use of public reservations by private interests can result when the best strategy for individuals conflicts with the "common good". In such a scenario, it asserts that even though the contribution of each "bad actor" may be minute, when the results of these actions are combined the resource could be degraded to the point of uselessness. This concern has led to the regulation of the spectrum.