Preparing for New Wireless Spectrum Policies, Is the GNSS Industry Ready?

R. Lee, J.D. Litton, P. Williams

Abstract:	New spectrum standards are gaining consideration driven by the need for mobile and in particular broadband services that use wide swaths of radio spectrum --- hundreds of megahertz – which straddle the L1 and other GNSS service bands. There is a broad consensus on exponential growth of wirelessly delivered broadband traffic. While much wireless traffic is delivered across frequencies well-separated from GNSS using unlicensed radio access, a substantial rise in traffic will occur over licensed spectrum nearer to GNSS spectra by new and existing wireless operators which must procure additional spectrum to support rising usage of consumer and business broadband services. Equally significant, mobile satellite services (MSS) operate on frequencies directly adjacent to the GNSS L1 band. These services are important to global broadband service reach. MSS is also forecasting significant growth over the next five years as MSS satellites with substantially increased capabilities are being rapidly added and replenished. The recent LightSquared FCC proceeding revealed inadequate spectrum management and planning where no party gained. Various reasons for this breakdown have been offered to explain the lack of appropriate plans to minimize disruption as new radio services are added. Waiting until such breakdowns occur is economically inefficient. The situation thus demands greater industry and regulatory preparation to avoid similar debacles in the future. The goal of all stakeholders should be to avoid erosion of the GNSS spectrum resource while still enabling growth of new terrestrial broadband services, including those which operate lawfully in spectrum proximity to GNSS. What are these standards or regulations? Are they sufficiently farsighted to avoid harmful interference to GNSS while using terrestrial service spectrum efficiently? GNSS has internationally allocated bands, but spectrum allocation rules are oriented around regulation of transmissions and not (broadly speaking) specifications on receivers, specifically rules related to receiver performance to mitigate interference from nearby adjacent band transmitters. GNSS operations with notable exceptions tend to be receive-centric given there are now in excess of one billion active GNSS receivers served by just over sixty to reach just over one hundred GNSS satellites transmitting signals. Further, certain GNSS services are ubiquitous; some segments are increasingly serving continuous operations (such as providing continuous synchronization to serve broadband mobile communications). Therefore, GNSS service must deliver robust facilities equivalent to safety-of-life standards. New radio interference standards or regulations must anticipate future requirements. Some in the GNSS industry question if current OOBE regulations are adequate to avoid compromising GNSS by inducing receiver noise floor rises as more mobiles and unintentional digital device radiation proliferate with little or no control. An analysis of this form of interference will be presented to address GNSS protection within a more crowded spectrum world. This paper will assess new proposals for their adequacy to protect GNSS services and spectrum including serious recommendations such as the “harm-claim threshold” proposal intended to address compatibility and regulation of adjacent band interference. We will also evaluate similar protection concepts for out of band emission levels (OOBE) to protect GNSS from proliferation of mass market communication and ever higher frequency stray emissions from digital devices.
Published in:	Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013) September 16 - 20, 2013 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	3378 - 3390
Cite this article:	Lee, R., Litton, J.D., Williams, P., "Preparing for New Wireless Spectrum Policies, Is the GNSS Industry Ready?," Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013), Nashville, TN, September 2013, pp. 3378-3390.
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