Mobile Future

New Analysis of Spectrum Sharing Complexities Outlines How to Move Forward

Report calls for stable, predictable and manageable approach to spectrum sharing


(Washington, DC) – Today, wireless network expert Peter Rysavy of Rysavy Research, in conjunction with Mobile Future, released a new paper “Complexities of Spectrum Sharing –How to Move Forward,” examining some of the challenges presented by sharing spectrum. Sharing mobile airwaves is one of many approaches to address accelerating consumer demand that is straining today’s mobile networks. The analysis outlines a number of recommendations for a stable, predictable and manageable approach to spectrum sharing.

The report stresses that while clearing spectrum for commercial use is the preferred path forward, government and industry spectrum sharing may be a necessary approach in certain spectrum bands. The analysis outlines existing spectrum sharing technologies, but cautions that those technologies do not solve the problems needing to be addressed for contemplated sharing scenarios. Investigations into spectrum sharing have raised the following concerns:

  • Overly conservative assumptions for government systems
  • Inappropriate or overly-simplistic modeling for protection and exclusion zones
  • The potential of exclusion zones rendering spectrum non-useful
  • The disparity and multiplicity of government systems
  • Restricted information regarding government systems hampering industry analysis.
  • Lack of detail about coordination requirements

“The design of the spectrum-sharing management system, as envisioned for the 3.5 GHz band, is likely to be the most complex ever developed, involving new architectural concepts, protocols, interfaces, stringent security, and policy-enforcement methods,” said Peter Rysavy. “Those precise technical, regulatory and political complexities must be fully addressed to craft a successful and nationally beneficial spectrum management system.”

To address the multifold challenges of spectrum sharing and ensure meaningful progress, Rysavy details specific recommendations based on sharing scenarios, some of which include:

In the case of most government users relocating, with some users remaining and sharing with non-federal users (e.g., as in the AWS-3 band):

    • The government needs to use realistic and real world interference assumptions;
    • Industry and government need to agree upon realistic propagation models;
    • Industry and government should take advantage of the recently established trusted-agent process; and
    • Government should vacate as many systems as possible from the spectrum and adopt simple sharing and coordination approaches.

In the case of sharing being managed by a combination of coordination/protection zones and dynamic access technologies (e.g., as contemplated in the 3.5 GHz band):

    • Ongoing measurements should be considered to progressively refine models and protection zones;
    • Geographic protection zones should protect incumbent users rather than new entrants;
    • The Spectrum Access System (SAS) should not exercise direct control of networks;
    • SAS rules should assume the appropriate use-case scenarios to protect against co-channel interference;
    • Rules should segment spectrum to minimize the possibility of general access users interfering with users that have priority over general access users; and,
    • Spectrum allocations should be assigned to priority service providers on a longer-term (non-varying) basis.

The report concludes that spectrum sharing will be successful only to the extent that all stakeholders—including government, commercial providers, and the technical community—are motivated and have appropriate incentives to share spectrum. Success will also depend on whether these stakeholders can agree on a realistic path forward. Limiting the scope of sharing while establishing achievable and definable milestones in these initial stages will both simplify what inevitably will be a multi-year development process and increase the likelihood of its ultimate success.

“Getting additional spectrum into the wireless marketplace must continue to be a national priority. It is the surest path forward to bolster our economy and secure our nation’s mobile broadband leadership,” said Mobile Future Chair Jonathan Spalter. “Success with spectrum sharing is predicated on a collaborative approach to developing economically sound and technically viable sharing technologies that foster competition, encourage innovation and fortify our mobile future.”

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Rysavy Research LLC is a consulting firm that has specialized in wireless technology since 1993. Projects include analysis of spectrum requirements for mobile broadband, reports on the evolution of wireless technology, evaluation of wireless technology capabilities, strategic consultations, system design, articles, courses and webcasts, network performance measurement, test reports, and acting as expert in patent-litigation cases.

Mobile Future is a coalition of cutting-edge technology and communications companies and a diverse group of non-profit organizations, working to support an environment that encourages investment and innovation in the dynamic wireless sector.  Our mission is to help inform and educate the public and key decision makers in business and government on the broad range of wireless innovations that are transforming our society and the nation’s economy.