WASHINGTON–In July 2015, a technical capabilities test was conducted on a new technique for delivering real time video to first responders.
Computer screen showing a datacast transmission of an alert message. (U.S. Department of Homeland Security)
The test involved a simulation involving two “intruders” in the University of Houston’s Cougar Place Residence Hall, where the two were monitored via security cameras as they walked through the dormitory. At the same time, two University of Houston police officers, each in their respective vehicles, monitored live streams of the security footage on their laptops.
The footage was transmitted to the University’s Emergency Operations Center via the broadcast signal assigned to KUHT, the city’s public television station.
In an effort to strengthen communications for first responders, since 2014 the Department of Homeland Security’s Science & Technology Directorate(DHS’ S&T) has been testing a new method for delivering data that, at its core, leverages terrestrial television signals from public broadcasters.
Referred to as datacasting, the method is regarded as more reliable than traditional, cellular or landline network connections used to send crucial information to first responders during emergencies. This is because, since it is a dedicated broadcast transmission, “it is not accessible by the public, so it cannot become congested like other commercial services,” says Cuong Luu, program manager at the DHS’ Science & Technology Directorate.
As a broadcast signal, it can be delivered to an unlimited audience with no bandwidth limitations and, according to Luu, with an added benefit: “Unlike regular TV broadcasts, all public safety data is encrypted and targetable to an individual or groups of receivers.”
A laptop in a UHPD patrol car, as it was used during the exercise. (U.S. Department of Homeland Security)
The setup for the DHS’s datacasting consisted of a multiplexer to integrate data into the TV signal prior to transmission, server, receiving antenna, and USB dongle for the laptops, which had Linux-based datacasting software to decode the information and present it in an understandable format.
While there are hurdles to overcome to take datacasting mainstream, Luu added that the equipment to support datacasting already exists and any updates for stakeholders would be relatively inexpensive because the technology is based on existing infrastructure used by all public broadcasters.
Currently datacasting can only be used to transmit data from a central location–for instance like a command or control center–to multiple receivers. It can be used alongside LTE service, which is how Luu and his team have been able to incorporate video from moving vehicles into content that is later broadcast to a receiver. In one particular test, footage from a cell phone was sent over LTE and then converted so that same video could be sent over a broadcast signal.
“The advantage of using datacasting in concert with LTE is that LTE spectrum can be more efficiently allocated by using a small amount of upstream LTE bandwidth to bring content in, and then datacasting to deliver content out to an unlimited audience,” said Luu.
Once the proposed ATSC 3.0 next-gen broadcast TV standard is adopted, Luu expects mobile capabilities for datacasting reception from moving vehicles to be improved upon. Currently, an external datacasting receiver is required in order for a computer to pick up information, but if mobile devices with ATSC 3.0 reception capability eventually hit the market, the range of service could be greatly expanded. “When that happens datacasting will become just another pathway to deliver content to a unified device,” Luu said.
However, it’s important to note that ATSC 3.0 will not eliminate the need for all of the tools and processes that datacasting requires.
Any content that can be sent over LTE can be sent via datacasting. This includes files that contain blueprints, text, voice alerts and of course video. In the University of Houston test, the two officers in the vehicles received from the campus’ EOC a text and voice alert, an audio file containing simulated recording of a 911 call and maps of the campus and dormitory. As for video quality, Luu says, “whatever quality is transmitted can be delivered with no quality degradation.”
The Department of Homeland Security’s Science & Technology Directorate plans to do another datacasting test like the one in Houston but in a rural environment where network coverage is limited. As for a projected date where this practice could start to be used as a standard, the DHS’ S&T says they haven’t set one up yet but are actively seeking to get an official agreement signed with America’s Public Television Stations, an advocacy organization for public television stations. By doing so, the DHS’ S&T says it’ll be easier to spread the benefits of datacasting—including easy accessibility as well as capability gaps and technology requirements—to APTS’ members and the rest of the public.