COCKEYSVILLE, MD.—The Sinclair Broadcast Group, along with the Pearl TV consortium, hosted yet another ATSC 3.0 device interoperability test at the ONE Media lab at SBG headquarters in the Baltimore suburb of Cockeysville, Md., June 3-7. 

The latest in a series of ongoing trials, this interop event was focused on such NextGen TV elements as digital rights management and signing in connection with MMT (MPEG Media Transport) and ROUTE (Real-time Object delivery over Unidirectional Transport), the Advanced Emergency Information broadcaster application, as well as basic interoperability testing of new models from TV set manufacturers.

According to Mark Aitken, SBG’s SVP of advanced technology, this is the sixth time Sinclair has sponsored an interop, the first occurring in 2016. It is also the first fully in-person testing event post-pandemic.

 The testing sessions involved most of the major hardware and software players in the field of NextGen TV—some two dozen—including encoder technology providers, emergency alerting gear, test equipment and receiver manufacturers. In addition to providing the facility, SBG also distributed ATSC 3.0 off-air signals from Baltimore broadcasters to provide a real-world environment. 

Jason Kim, ONE Media Engineer and coordinator of the event, said that literally thousands of tests were scheduled to be performed during the four-and-a-half-day event.

“There are many air chain equipment combinations—encoders, packagers, schedulers—with the ways things are implemented in each varying from vendor to vendor,” he said. “For instance, one encoder will be tested with a combination of all different packagers. By the time everything is finished), there will be thousands of different combinations trialed.”

What's Driving This 'Interop?'
With ATSC 3.0 now available to more than 75% of U.S. households, one might ask: Why is such continued testing necessary?  Weren’t all of the pieces fitted together a long time ago? It works—why do we need more interoperability testing?

The answer is both “yes” and “no.” While NextGen TV is—and has been—informing and entertaining broadcast audiences, it was designed to be flexible and extensible in terms of feature sets and functionalities as the technology surrounding it evolves. 

 “There are parts of the standard that are in the ATSC’s ‘Candidate’ phase, and it’s usual before putting these to a full vote of the ATSC membership that the Candidate Standard be fully vetted,” Aitken said, adding that testing on some elements of the standard was intentionally sidelined as the new TV service emerged. 

“MMT, which is one of two transport mechanisms in the standard, was put off for implementation intentionally by the big TV manufacturers,” he said. “We are now finalizing the MMT side of transport, particularly around security and DRM (digital rights management) and those related activities.”

 Aitken added that a very important aspect of the security-related portion of plugfest testing this time involved “signing.”

 “This is testing the certification by the broadcasters that it’s their content (signal and application), and also expiration of that certificate,” he said. “When in the process of exchanging this secure content along with DRM and the authorization to receive the content, the certificates expire,” he said… “and when those certificates expire—they are intentionally allowed to expire in this testing—we want to watch to see what happens to the various TV sets and set-top boxes.

 “The whole purpose of security (signal and application signing) and DRM is to protect the user and the content, and the other side of the equation is that when the related certificates and DRM keys expire, you want to make sure that the sets operate normally and don’t get locked up,” he added.

Ensuring the New ‘Keys’ Fit All of the Existing “Locks’
Plugfest coordinator Kim noted that such compatibility testing is becoming more and more crucial as NextGen TV matures.

“As we deploy more of the advanced features of ATSC 3.0, interoperability has become more important than ever,” he said. “Right now, we are deploying services that we weren’t able to with 1.0, so there are a lot of new features that we are deploying as part of ATSC 3.0 service. So, we want to make sure that all receivers can support the services we are providing.”

In describing the trialing, Kim observed that it begins with some basic or “baseline” testing as a generalized health check of receivers from multiple manufacturers. 

“We call this ‘watch only’ TV,” he said. “It’s basically to see if all of the receivers function with over-the-air signals from our rooftop antenna. We want to baseline all the receivers that are here to ensure that they can support basic audio and video services. Once this is done, we go into different features that are now in production or that are going to be deployed.”

Kim said an important part of the testing for Sinclair was in evaluating “what we call ‘BEST (Broadcast-Enabled Streaming Television) Channel,’ where we are broadcasting the media presentation description over-the-air and the receiver is also pulling audio and video segments from a broadband connection.”

He noted that SBG has initiated this dual-delivery mechanism in some 40 markets over the past several months, but a few glitches were observed in the rollout.

“When we first deployed it, not every receiver supported it,” he said. “We are working together with the receiver guys that are here at the interop and with our broadcast air chain companies to make sure that our new BEST channel is supported by all receivers out there. We want to make sure what we are deploying can be received by all receivers.” 

What's it Like at an Interop?
For those not familiar with plugfests, perhaps the best way to describe the environment as something akin to a college study hall, with individuals huddled over laptop computers and a generally hushed atmosphere. There’s an adjacent break room where participants are free to fortify themselves with snacks, coffee, and soft drinks. 

What sets an “interop” event apart is that there are multiple (a dozen or so) wall-mounted large screen television receivers filling up most of the available lab wall space, and two distinct groups of players or teams—the “transmitters” and the “receivers”—continuously interacting with each other. The first group sends out various sets of computer code and the other attempts to decode it across multiple devices or device simulators. Such trialing is necessary to ensure complete compatibility between all hardware and software used in NextGen TV broadcasting.

Most of the communication among players is via computer keyboards and displays, with only an occasional “in-person” visit from a representative of one group with another when there’s a snag. Such events are essential in delivering an end-to-end digital television system that performs without any hiccups, as a very minor parameter change “upstream” has the potential to disable functions or even shut down operations in devices that are “downstream.”

Aitken noted that timing and location of this latest interoperability testing event was planned to facilitate attendance at the June 12-14 ATSC NextGen TV Broadcast Conference in Washington, D.C. by out-of-area plugfest participants—particularly those based outside the United States. 

The plugfest attracted some 65 participants from seven countries, who represented some two dozen companies. These included ADTH, Airwavz, Alticast, Ateme, DigiCAP, DS Broadcast, DTV Innovations, Enensys, Gray Television, Heartland Video Systems, Hisense, Harmonic, iWedia, Koherence, Lowasis, NBC Universal, Pearl TV, Samsung, SBG, Sony, TCL, Triveni Digital, Vbox, and Verance.

HUNT VALLEY, MD.—Sinclair Broadcast Group is among the largest stations groups in the United States with 193 stations in some 100 U.S. markets and is also recognized as a frontrunner in the development and deployment of ATSC 3.0. However, there’s been little public awareness of the advanced television testing facility created a few years ago within the Sinclair corporate facility in Hunt Valley, Md.

Tucked away on a lower level of the building, and without much signage to call attention to it, the 1,100-square foot “L”-shaped laboratory was formerly inaugurated in 2016 and is officially known as “ONE Media Labs” (ONE Media is the designation for “think tank” innovations arm of Sinclair). Since its formal inception (and even before) the unit has stayed busy with experimentation by both Sinclair employees and the collaboration of others involved in carving out the road to television’s next generation operating platform.

Marshall Behrmann

Asked about the mission of the facility, Marshall Behrmann, the senior lab engineer, described it as a test bed for virtually anything having to do with ATSC 3.0.

“We perform integration, testing and evaluation of a lot of 3.0 products and subsystems,” said Behrmann. “We also do systems engineering work and interoperability testing—‘plugfests.’ Most recently, we were involved in some extensive evaluation of new software-based Harmonic and Ateme encoder products. We needed to establish the density level in connection with ATSC 1.0 MPEG-2 compression. This is an important parameter as we move into the repack and the addition of extra program streams associated with channel sharing and literally involved months of work.”

OPEN TO ALL OF THE ATSC 3.0 COMMUNITY

Although much of the work involves Sinclair-related efforts, Fred Baumgartner, Sinclair’s director of next-generation implementation, was quick to point out that the facility is open to anyone wanting to perform testing related to the ATSC 3.0 DTV transmission standard.

Fred Baumgartner

“We work with everyone,” said Baumgartner. “It’s very open. If someone wants to come and play, we let them in—anybody with a real business interest in ATSC 3.0. There aren’t a whole lot of barriers.”

(This is very much in line with Sinclair’s proactive part in development and promotion of ATSC 3.0. The company hosted 3.0-related industry plugfests in 2016 and 2017 that involved players from around the world. The number of participants was such that these events were held in the ballroom of a nearby Hunt Valley hotel.)

[Sinclair/ONE Media Host Second ATSC 3.0 'Plug Fest']

Behrmann noted that the lab itself had hosted testing of products from companies including Triveni Digital, DigiCap, Enensys, DS Broadcast, Ateme, Harmonic, LG, Samsung, Sony, CleverLogic and just about every other entity involved in advanced television.

“Anybody can come and use the facility, so long as they clear it with Mark,” said Behrmann, [Mark Aitken is Sinclair’s vice president of advanced technology, president of ONE Media, and oversees laboratory operations.]

‘WE CAN DO ANYTHING’

The ONE Media lab even includes an area for subjectively observing ATSC 3.0 video and audio. It’s been dubbed “the living room of the future.”

The ONE Media lab is chock full of test gear, including ATSC 3.0 signal generators, monitoring gear, precision demodulators, video and audio sources and the sophisticated measuring equipment necessary to create just about any real world or imagined scenario involving digital television and its transmission and reception.

“We think we have the best-equipped ATSC 3.0 testing facility in the country,” said Behrmann. “It’s really second to none. It may be the best-equipped facility in the world, but I haven’t had the opportunity to visit the ETRI facility in South Korea.” [ETRI, the Electronics and Telecommunications Research Institute, is a South Korean research organization that has played a big part in the development of ATSC 3.0. ONE Media and ETRI have been open collaborators and have co-authored many papers advancing the frontiers of NextGen research.]

[Test We Must!]

Asked about how much money was invested in the laboratory, Behrmann said that it would be difficult to come up with an exact figure, as some amount of the gear being used was on loan from vendors, but he estimated that it would take $2.5 million or more to recreate such a facility.

Ian Hoots

“It could easily amount to that much,” said Ian Hoots, who works as a systems engineer with Acrodyne Services, a Sinclair subsidiary that had a hand in setting up the lab. “We have one exciter alone that is worth about $30,000, and when you have at least one of everything, all of this adds up pretty quickly.”

Asked about his part in the operation, Hoots explained that he was there to help with the initial construction, but testing and developmental work was going on even before he arrived in 2016.

“This is where they created the ATSC 3.0 ‘bootstrap’,” he said. “But that was before me. We have the prototype gear—the platform they used for developing the bootstrap—hiding away in our storage cage, but it’s old and clunky now. There’s some real history here.” [The ‘bootstrap’ is part of the 3.0 physical layer and with its fixed sampling rate, signal bandwidth, time-domain structure, subcarrier spacing and other attributes that are known to all receiving devices, and as such provides a universal entry point into the signal to allow its demodulation and decoding.]

[The ATSC 3.0 Physical Layer—Bootstrap Basics]

When asked about taking the bootstrap technology out of storage for a picture, Hoots stated that “there isn’t much to see; just a nondescript ‘black box.’ But we have it just for the sake of hanging on to it.”

(L-R) Behrman and Hoots pose with one of the ONE Media ATSC 3.0 test gear racks.

Hoots said the lab collection also included other 3.0 “relics,” including the earliest of the ETRI/CleverLogic prototype receivers.

“Early on, we had all these ways to transmit bits but zero ways to receive them, so these receivers were quite an important addition,” he said. “As time went on, we got an LG chip-based receiver from DS Broadcast. It’s actually a full IRD.”

THIS IS JUST THE BEGINNING

Asked about the future of the laboratory, now that the ATSC 3.0 standard is complete and the FCC has authorized its transmission, Hoots and Behrmann were quick to respond.

“We’re actually at the beginning of a long journey,” said Hoots. Behrmann recalled a conversation he had with Aitken, when he was asked about leaving his assistant chief engineer’s position at Sinclair’s WBFF Baltimore television outlet to work in the testing lab.

“I had some concerns about leaving my WBFF job and asked Mark how long he thought the 3.0 project would run,” said Behrmann. “He said that even if 3.0 ended, we would be moving out on ‘4.0!”

The new ONE Media mobile testing van. It features FCC-calibrated receiving antennas and a very sophisticated system for documenting off-air ATSC 3.0 signal measurements.

TAKING IT ON THE ROAD

Of course, a television transmission system, or any other technology, isn’t of much value if it’s only deployed within a laboratory. Sinclair/ONE Media recognized this early on and is now ready to move their testing and measurement operations out into the real world as U.S. stations begin to transmit ATSC 3.0 signals. In mid-2017, the lab purchased a vehicle to outfit as a mobile test lab and has spent the past six months or so building it out. Bill Soreth, a systems development engineer from Acrodyne Services, has led the effort, working with Behrmann and Hoots to select and load gear into the van and also to develop a plan for ATSC 3.0 field testing work.

“It’s basically an ATSC 3.0 receiving and measurement platform,” said Soreth. “We’ve got the latest CleverLogic and DS Broadcast receivers and RF capture technology that allows us to record the entire RF spectrum. There are two A-H Systems FCC-calibrated dipole antennas—one for vertical plane measurements and one for horizontal plane—on a 30-foot mast, as well as an omnidirectional antenna and a couple of other masts for additional antennas.

“We’ll be using an IMAS [Integrated measurement Analysis System] from AFT for GPS mapping,” added Behrmann. “It takes in all of your RF spectrum and meters it to give you bit-error rates and SNRs, and ties that to a GPS map and then takes a snapshot of that every second.” He added that the van also includes a roof-mounted camera for recording the various paths and locales taken by the vehicle.

“When we finish our drive testing, we can save the data and then take it back to the office for a complete analysis,” Behrmann said.

“We plan to use the truck for a lot of SFN test and measurement work as 3.0 rolls out,” noted Baumgartmer. “The initial drive testing will be largely to validate and adjust the ‘Progira Plan’ software that we using to plan SFNs in several areas.”

Bill Soreth performs a systems check of the gear inside the van.

Right now, this mobile ATSC 3.0 testing facility has only about 1,000 miles on the odometer—largely the mileage from the drive from its Boston supplier, Accelerated Media Technologies, and some practice runs in the greater Baltimore/Washington area for preliminary studies of the experimental 3.0 SFN signals that Sinclair has been radiating in those two markets; but Soreth, Hoots, Behrmann and Baumgartner all expect to see it travel a lot more in the coming years.

[One Media Conducts ATSC 3.0 'Concept' SFN Trials]

“The idea is to get everything right while we’re here in Baltimore,” said Soreth. “Then we start adding the milleage as we crisscross the country to document other markets.”