CHAT ROOM Testing, One-Two-Three…

Posted on November 8, 2017 in ATSC News

In the Chat Room this month, THE STANDARD sat down with long-time ATSC board member Lynn Claudy. He’s the senior vice president of technology for the National Association of Broadcasters, who is spearheading the joint NAB effort with the Consumer Technology Association on the “living laboratory” ATSC 3.0 test station in Cleveland, Ohio.

THE STANDARD: As ATSC 3.0 goes from the laboratory to the marketplace, what’s the role of field testing to support implementation?

CLAUDY: Since the time of the original Grand Alliance system field testing in Charlotte (North Carolina) in 1995, we’ve learned a lot about how various digital transmission systems deal with RF (radio frequency) propagation. And the notion that it’s necessary and valuable to assess the performance of new systems under real-world conditions is still quite valid. Back in ’95, there was a real question about whether digital broadcast systems could work acceptably in practical situations, and field testing was the only way to really answer that question. These days, simulation and analysis are great design tools and reliable predictors of many aspects of real-world performance, but you still can’t guarantee that all the challenging situations that are likely to be experienced will be fully uncovered without going out into the field.

To use not-too-far-fetched inside-the-beltway analogy, every year the Washington Redskins roster seems to undergo a radical transformation that makes it look like a great football team on paper. But the team’s performance on the field always seems to reveal weaknesses that weren’t anticipated and adjustments need to be made…usually too late, unfortunately. Back to broadcasting, with a flexible system like ATSC 3.0, field testing can provide important clues on how to best optimize the system, how to pick among the thousands of possible combinations of modulation and coding parameters for those that work well in specific practical scenarios.

Real-world testing always reveals some surprising insights about wireless communications systems. Fortunately, the extremely flexible nature of 3.0 allows for adjustments to be made that should help shore up any vulnerabilities that might be found. The results will no doubt be much more successful than those of the Redskins.

THE STANDARD: Please fill us in on the current status of the industry’s Next Gen TV test station in Cleveland.

CLAUDY: The Cleveland test station is a co-sponsored project by NAB and CTA (the Consumer Technology Association), hosted at Tribune Broadcasting’s WJW station. The goal of this project is to be a neutral test facility for broadcasters, consumer electronics and professional equipment manufacturers and anybody else in the overall television industry to test prototype and early commercial ATSC 3.0 equipment and services and to explore equipment interoperability.

In essence, the test station is meant to be a “living laboratory” for various activities centered on ATSC 3.0. At this point, we have all the basic building blocks for the ATSC 3.0 broadcast chain in place, with most of those blocks represented by multiple vendors.  We’re on the air, and we have receivers in several form factors. As more broadcast equipment and receivers become available, we hope the test station will be a useful stop along their journey to the Next Gen TV marketplace. Getting everything to work with everything else can be somewhat of a challenge, but the test station is poised to be a great learning resource for the industry. 

THE STANDARD: Lynn, how will the station support ATSC 3.0’s next phase as the industry moves toward deployment?

The ATSC has come up with a great transmission standard, but the standard doesn’t tell you how to connect together, control and monitor the individual equipment pieces that make up the system facility or how to build and use authoring tools for some of the advanced services and features that are documented in the standard. We think the test station has a role in helping fill those gaps.

Like the ATSC 3.0 system itself, we want to manage and operate the Cleveland test station in a flexible manner, to help solve system and performance issues as they come up. And we figured we’d find those issues most rapidly by just diving in and building and operating a working station. As we move closer to actual marketplace deployment, we’ll see more test stations out there, adding to the body of knowledge about solutions to implementation challenges – there’s certainly enough work to go around. In any case, now is the time to move from theory to practice. Although he didn’t know that ATSC 3.0 was coming, Aristotle got it right when he said: “For the things we have to learn before we can do them, we learn by doing them.”

Posted in ATSC News