So Soon? Next-Gen Broadcast TV In Works

It’s been less than two years since TV broadcasting switched off the last analog transmitter and went all digital. But the actual digital broadcast standard — ATSC DTV — is actually a lot older than that.

In fact, it’s 15 years old if you start counting from when the FCC adopted it, 16 if you start counting from when the consortium of technology companies — the so-called Grand Alliance — put the system together and a few years older still if you go back to when the various components of the system were actually invented.

That’s a long, long time ago given the lighting speed with which electronic media evolves these days. And that’s why far-sighted broadcasters and technologists, under the aegis of the Advanced Television Systems Committee, have begun work on the next-generation TV broadcasting standard.

Even as some viewers still fiddle with DTV converter boxes, next-gen proponents say a new system is needed within the next several years so that TV stations can broadcast more programming, more reliably to more places and explore new business opportunities.

“At some point, broadcasting, like everything else, has to move to the next stage of technology,” says Mark Richer, president of the ATSC, whose board is expected to take the next step toward a next-gen standard when it meets in Washington in two weeks.

Jim Kutzner, chief engineer, Public Broadcasting Service, and chairman of ATSC’s next-gen planning committee, agrees that it’s time. “If you don’t start now, many years down the road you’ll be in the same place.”

Kutzner also sees the effort as a hedge against the FCC’s proposal to take big swatches of spectrum from broadcasters and make it available to wireless broadband providers. The FCC is pushing the plan, despite stiffening opposition of broadcasters.

“If the broadcasters are consolidated down into a smaller amount of spectrum, then we will have far less spectrum to transition from where we are today to where we want to be in the future,” he says.

To be determined is the urgency. While some proponents would like to put it on the fast track and bring the standard home within five years, others are looking at five to 10 years.

Whenever it comes, next-gen TV will not be backward compatible with DTV as color TV was with the original black-and-white TV in the 1950s. This will mean another traumatic transition similar to one leading up to the final June 2009 switch from analog to digital.

“Sometimes to build a better mousetrap, you have to start over,” said Richer. “That’s what we are going to do.”

The standards-setting work is still in its early stages, but already there seems to be a consensus that the third iteration of broadcasting — the first was 1941-vintage NTSC — should be far more efficient in its use of spectrum than today’s DTV system. Proponents talk of achieving it in a couple of different ways.

First, the standard would feature improved compression of video, audio and other content. “Broadcasters could use far fewer bits to deliver the same program at the same quality or deliver higher quality using the same bits we use today,” PBS’s Kutzner says.

And, second, it would allow stations to pump more bits through any given bandwidth. How many more Kutzner couldn’t say, but certainly, he says, “a substantial improvement” over the 19.4 mbps in 6 MHz now possible with DTV. “There are new techniques that approach Shannon’s Law, the theoretical limit of the ability to push bits through a channel,” he says.

The standards setters would also look for a marked improvement in the transmitted signal so it could be received on small indoor antennas and on mobile devices.

The current DTV transmission system — VSB — has been criticized for its poor propagation, especially in the VHF band. To receive it reliably, rooftop antennas are needed in most places.

And for mobile service, ATSC had to come up with a supplementary standard that forces stations to use up precious bandwidth to transmit a second signal that is suitable for viewing only on small screens.

“The ATSC is not tasked with figuring out how can we deliver broadcasting to a wider area, but they are thinking about, within the area that stations serve, how can we up the reliability in more diverse receiving configuration like indoor reception,” says Lynn Claudy, SVP, science and technology, National Association of Broadcasters, which is taking an active role in the next-gen push.

One option already under consideration for the standard is a multi-carrier OFDM modulation scheme that was considered, but finally rejected, for DTV in the 1990s, and which is widely used in other parts of the world.

ATSC may be feeling a little competitive heat to get going on a next-gen standard. NHK in Japan is developing a system, Richer says. And in Europe, some broadcasters are already on the air with a second-generation standard called DVB-T2.

“It’s indicative that all the countries throughout the world that adopted a mid-1990 technology for digital transmission are looking at new systems that do better and transition scenarios that allow them to migrate either quickly or over the long term to that new system,” says NAB’s Claudy.

Some believe that DVB-T2, based on multi-carrier OFDM modulation scheme, would be a quick next-gen solution for the U.S.

Claudy is not endorsing any system at this point, but says that DVB-T2 could be a smart play if it becomes popular in Europe. “You would already have economies of scale and manufacturing capabilities built up and that might lead to an easier transition scenario than starting from scratch in the U.S.,” he says.

“On the other hand, we are such a big market that you don’t really need the economies of scale from global manufacturing to have a cost-reduced and ubiquitous mass market.”

Some next-gen proponents would also like to see more flexibility built into the standard so that broadcasters would not be confined to 6 MHz all of the time and so that they could “broadcast” content for wireless mobile providers.

Among the drivers of the next-gen standard on the broadcasting side is Mark Aitken, director of advanced technology for Sinclair Broadcast Group. He wants the new standard within five years, arguing that the current standard is no longer up to the job.

“It’s no secret [the DTV standard] has never been what it was cracked up to be,” he says. “We need more bit capacity, we need more reliable service and we need the ability to seamlessly stitch together markets with a quality service that would support virtually any business model.”

Aitken’s big idea, shared at an ATSC planning committee symposia, is to adopt an OFDM system that would complement the new 3GPP LTE standard that the wireless mobile operators intend to use to “multicast” linear video in a broadcast-like one-to-many service.

With compatible or “converged” systems, broadcasters and wireless carriers could work together, Aitken says. Broadcasters could deliver their own local programming services and emergency alerts to phones and step in to deliver multicast video for the carriers whenever demand threatens to overwhelm their networks.

“You could imagine a 4G telephone that could tune to a specific UHF frequency and receive LTE content being emitted by a broadcaster,” he says.

Aitken also believes that the move to the next-gen standard should be accompanied by a move to distributed networks of many transmitters that would provide better coverage of a market than the single transmitter with tall tower now employed in broadcasting.

“The ATSC should give serious consideration to new broadband-broadcast system architectures and not focus only on the component technologies…,” he says in his ATSC paper, which was co-authored by Mike Simon, of Rohde & Schwarz.

Aitken’s proposal dovetails with that of Capitol Broadcasting, a station group whose flagship is WRAL Raleigh, N.C. In an FCC filing, Capital has proposed adopting a next-generation OFDM system that would allow stations to handle the video multicasts of the wireless carriers for a fee.

“The idea is that if they get real high demand for certain video, then they switch it from wireless Internet to broadcast,” says CEO Jim Goodmon. “Broadcast takes a good bit of the video load off the wireless broadband system. What this means is, you have all these devices — cell phones. They’ve also got wireless Internet, and they also have a broadcast chip.”

ATSC’s next-gen initiative is already a year old. It began last May with the formation of Kutzner’s planning committee and over the past year it has held two day-long symposia during which broadcasters and technology companies presented papers on what the next-gen system should be and could be.

The planning committee is scheduled to report its findings and recommendations on May 12 to the ATSC board, which is expected to endorse them and pass them along for further discussion during strategy sessions this summer.

Out of those sessions should come a vote in July or September to assign next-gen to a technology group, which will begin the formal standards-setting work.

The group’s first order of business will be to define precisely what the requirements and the attributes of the new system should be and set a time frame for the work, Richer says. “Before you specify any technology, you need to know what you are trying to do,” he says.

Richer stresses that the work on next-gen broadcasting will not slow parallel work on standards to improve and enhance today’s DTV system. “That’s where we are focused and that’s where will we stay focused for the coming few years.”

To date, the most concrete manifestation of that commitment has been the mobile DTV standard, which broadcasters are still hoping to bring to market this year.

Other DTV efforts involved developing standards for broadcasting 3D and non-real-time programming.

Although some next-gen proponents have definite ideas, Richer cautions against trying to divine what the new standard will look like at this early stage. “There will be people coming out of the woodwork with technologies,” he says. “There will be things we know and things we have never heard about. The way we are going to approach it will be with open arms and trying to get as many organizations involved as possible.”