Institute for Telecommunication Sciences
the research laboratory of the National Telecommunications and Information Administration

What We Do

The Institute for Telecommunication Sciences (ITS) performs cutting-edge telecommunications research and engineering with both federal government and private sector partners. As its research and engineering laboratory, ITS supports NTIA by performing the research and engineering that enables the U.S. Government, national and international standards organizations, and many aspects of private industry to manage the radio spectrum and ensure that innovative, new technologies are recognized and effective. ITS also serves as a principal Federal resource for solving the telecommunications concerns of other Federal agencies, state and local Governments, private corporations and associations, and international organizations. The FY 2015 Technical Progress Report describes research performed in the past fiscal year.

Register now for ISART 2017!

ISART 2017: Spectrum Mining at Millimeter Waves Set for August 15-17 in Broomfield, Colorado

Digging for Capacity: As more spectrum users squeeze into the lower frequency bands, more are also exploring the higher frequencies to meet their capacity needs. Millimeter wave frequencies, approximately 20 GHz and above, are able to meet some needs. ISART 2017, the 16th in this series of high quality symposia will explore millimeter waves, the technical challenges they present, and applications that use them. This year’s tutorial and four panels will approach this topic from five different perspectives: regulation, industry, standards, measurement and modeling, and systems. Industry demonstrations and poster sessions from academia will round out the conference. The goal of ISART 2017 is to get us all talking, exploring new ideas, brainstorming, and perhaps even solve a couple of millimeter wave obstacles. To take advantage of potential synergies, a CSMAC meeting and a WSRD meeting are scheduled during the same week. Read more here, check out the Draft Agenda and the Panel Descriptions, and register here.

Research Spotlight: A Promising Crowdsourcing Research Experiment

The results are in—when it comes to speech intelligibility testing, the crowd and human subjects in a lab have a lot in common. Initial results from a crowdsourced speech intelligibility test designed by ITS align closely with similar testing done in the lab. Since crowdsourced testing requires significantly less time and money than laboratory testing, this could help ITS quickly gather large amounts of high-quality speech intelligibility data as part of a more efficient overall test plan.

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ITS Open Sources the Extended-Hata Urban Propagation Model

Evolving and improving the science behind spectrum sharing is essential to NTIA’s commitment to meeting the demand for spectrum among federal and commercial users. Just as collaboration between spectrum users can unlock sharing opportunities, researchers can work together to advance spectrum efficiencies and mitigate interference.

ITS has taken a major step toward better collaboration by publishing a reference implementation of the Extended-Hata Urban Propagation Model (eHata) in the NTIA/ITS GitHub at https://github.com/NTIA/ehata. ITS created eHata to predict propagation of new commercial broadband services in the 3.5 GHz band. An analysis of those predictions enabled regulators to significantly expand commercial access to the 3.5 GHz band through the establishment of the Citizens Broadband Radio Service (CBRS). The analysis was presented in Technical Report TR-15-517: 3.5 GHz Exclusion Zone Analyses and Methodology. The analysis was based on propagation predictions performed by extending the Hata model, a radio propagation model for outdoor cellular transmissions at 150-1500 MHz that considers the effects of diffraction, reflection, and scattering caused by city structures. To predict propagation of new commercial broadband services in the 3.5 GHz band, NTIA engineers extended the Hata model in both frequency and distance, creating the Extended-Hata Urban Propagation Model (eHata).

The Hata propagation model considers the effects of diffraction, reflection, and scattering caused by city structures for outdoor cellular transmissions at 150-1500 MHz. NTIA engineers created eHata by extending the Hata model in both frequency and distance. By providing an open source implementation that is freely available for use and re-use, ITS hopes to advance development of widely accepted propagation models. Rather than duplicating efforts with competing versions of eHata, researchers can focus on enhancing and improving the open source implementation.

The Wireless Innovation Forum’s Spectrum Sharing Committee, which is developing the technical standards for the Spectrum Access System (SAS) that will enable commercial operations in the 3.5 GHz band, has proposed using eHata to calculate coverage and protection areas. WInnForum can now use or adapt the ITS source code for propagation prediction and focus their efforts on developing other aspects of the SAS functional architecture. The code can also allow other organizations and researchers that are interested in urban propagation modeling to engage with ITS to explore how best to model urban environments.

Whereas papers and reports disseminate knowledge unidirectionally, open source code repositories allow for two-way collaboration between ITS and the research community. ITS plans to continue to release open source reference implementations as it adds to the body of basic research on radio propagation modeling. These releases transfer the results of federally funded research and technology development to other researchers in this area, allowing other federal agencies as well as industry to leverage 100 years of ITS research expertise to address current and future spectrum issues.

 

New Publications

This Month in ITS History

July 1968: Irregular Terrain Model Published

In July 1968 one of ITS’s most famous publications was released. “Prediction of Tropospheric Radio Transmission Loss Over Irregular Terrain: A Computer Model” described a software product based on the groundbreaking work done for Tech Note 101 three years earlier. The FORTRAN program created by ITS engineers Anita Longley and Phil Rice is better known as the Irregular Terrain Model (ITM) or simply Longley-Rice. This was one of the first computerized models of radio propagation that could be used effectively in the real world. It incorporated general terrain features, climate, antenna characteristics, and wavelength into a general propagation model. The computerized model could be used to predict the propagation between two points or to predict the full propagation from a transmitter. To verify their work the team compared the model's predictions to over 800 measured communications paths from around the world. ITM predated digital elevation databases, and was used heavily for decades after its publication. The FCC used the Longley-Rice model for expansion of both satellite and digital television allocations. ITM remains an important propagation model almost 50 years later, and the software implementations in FORTRAN and C++, dated as the languages are, are still among the most downloaded ITS software. ITS continues to improve and update the model, which remains a fundamental tool in the effort to maximize spectrum utilization.