September 27, 2016
Stephen D. Voran and Andrew A. Catellier of ITS were honored today with the Department of Commerce (DoC) Silver Medal Award for designing and executing a highly compressed speech intelligibility testing regime that produced internationally accepted authoritative results to inform international standards under development for next-generation wireless communications equipment. The Silver Medal is the second highest honor granted by the Secretary of Commerce for distinguished and exceptional performance.
The work was performed on behalf of the First Responder Network Authority (FirstNet) as part of the Public Safety Communications Research (PSCR) program, a joint effort of NTIA and the National Institute for Standards and Technology. The research was sponsored by the Department of Homeland Security (DHS), which leads an ongoing effort to enable interoperable emergency communications among 60,000 Federal, state and local public safety agencies. These agencies will benefit from Voran and Catellier’s work by being able to purchase internationally standardized commercial off-the-shelf equipment to meet their mission critical communication needs. Dean Prochaska, Director of Standards for FirstNet emphasized, “The work that Stephen and Andrew performed provided the basis for 3GPP to select a voice codec that meets the needs of public safety for inclusion in the next release of international LTE communications standards, and manufacturers all over the world will include that codec in new equipment designs."
FirstNet, an independent authority within NTIA, was established by Congress to develop and deploy a nationwide public safety broadband network (NPSBN). The public safety community chose LTE as the most promising technology for a robust and efficient NPSBN, and FirstNet committed to building the network to open standards to take advantage of increased vendor competition and economies of scale, driving down the cost to public safety users while opening the market of millions of public safety users to more vendors. Standards for commercial LTE equipment (such as smartphones), however, did not include many critical requirements to help meet public safety communication needs.
The National Public Safety Telecommunications Council (NPSTC), a federation of public safety organizations, identified audio quality as a critical requirement for mission critical voice communications over the NPSBN. Standardized algorithms for digital audio (codecs) compress speech for transmission over a network and decompress it for playback. When loud background noise is mixed with speech—a typical scenario in public safety communications—codecs with greater noise resistance are needed to provide acceptable speech intelligibility. Speech intelligibility testing is the primary means by which public safety evaluates a voice codec, and that testing was not included in standards bodies’ deliberations on selection of a voice codec for the next LTE standard.
To remedy this, Voran and Catellier designed and executed a testing regime that accelerated speech intelligibility testing that normally would have taken 12 months into two months. Catellier was able to present test results that showed the intelligibility performance of different LTE speech codecs at meetings of the 3rd Generation Partnership Project (3GPP, the international standards organization for LTE commercial wireless broadband networks). Based on those results, representatives of the United States and five other countries took a strong and unified position on which voice codec is most suitable for the public safety user community, ensuring the next 3GPP release would contain a voice codec that meets the needs of public safety. Voran and Catellier’s work directly informed the international technical standards that will ensure that public safety mission critical voice communications requirements will be met by next-generation commercial off-the-shelf equipment worldwide. The compressed testing regime devised by Voran and Catellier models a fast-response, targeted research effort that builds on long-standing expertise to produce reliable and trusted objective results to inform international standards. Including speech intelligibility testing in future evaluations of voice codecs at 3GPP ensures a single stream evolution for public safety and commercial communications technology.
FirstNet and all subscribers will realize significant cost and time savings if internationally standardized commercial off-the-shelf equipment that meets public safety’s needs is available to operate on the NPSBN when it is launched.