When the DVB-T2 standard was published in 2009, it was the first—and for awhile the only—second-generation Digital Terrestrial Television (DTT) standard. Because of its superior spectral efficiency and its operational flexibility, DVB-T2 has successfully been deployed around the world and is the technology of choice in many countries. Now, with ATSC 3.0 deployments underway, there is another second-generation DTT specification.

This article will explore the relevant differences between ATSC 3.0 and DVB-T2, starting with a comprehensive comparison of the physical and transport layers of each standard. Next, the article will evaluate the audio and video coding technologies that the systems support, noting the advantages of each approach with regards to equipment costs and licensing fees. With the growing popularity of smart and connected TVs and widespread broadband access, the article will conclude with a look at how ATSC 3.0 and DVB-T2 approach interactive service delivery and why the latter standard remains the strongest candidate for implementation of DTT services.

COMPARING THE PHYSICAL LAYERS

Only marginal differences for the spectral efficiency of a single channel exist between the physical layers of ATSC 3.0 and DVB-T2. The physical layer of ATSC 3.0 was built upon the same basic architecture as DVB-T2, which features OFDM and LDPC Forward Error Correction Codes. While ATSC 3.0 does include additional new tools such as non-uniform constellations and advanced LDPC codes, it only offers a slight improvement in performance that doesn’t outweigh the increased complexity.

There are additional new tools in ATSC 3.0, like MIMO (Multiple-Input and Multiple-Output) and LDM (Layer Division Multiplexing). DVB analysed the benefits of MIMO some years ago and made a deliberate decision not to include it in DVB-T2, owing to a lack of commercial demand for it. DTT operators expressed concern about the more complex and expensive network infrastructure its introduction would require. Furthermore, the introduction of MIMO forces the end user to install a new receive antenna.

LDM can provide spectral efficiency improvements for a limited choice of injection levels. The right mix of different injection levels is not always a typical use case and limits the use of LDM, which also adds complexity and cost to the receivers.

From a modulation perspective, ATSC 3.0 can operate up to 1024 and 4096 QAM, compared with DVB-T2 where the highest option is 256 QAM. The higher modulation scheme of ATSC 3.0 allows for more bits per symbol but it also introduces a higher signal-to-noise ratio, requiring a denser and thus more costly network. Currently, there is no market demand for constellations beyond 256 QAM in Europe. Indeed, the Recommended Practice for ATSC 3.0 television sets, issued by the CTA, mandates only constellations up to 256 QAM, indicating a similar market need in North America.

EXAMINING THE TRANSPORT LAYER

The transport layer of ATSC 3.0 moves away from MPEG2 Transport Stream (TS), which is well established in the industry. Instead it relies on an IP system based on the DASH Route and MMT specifications (Fig. 1). DVB, on the other hand, maintains that MPEG2-TS continues to be the best technical solution for unidirectional distribution of broadcast content, including terrestrial, satellite and cable.

By using MPEG2-TS, broadcasters can create a TS signal once and use it for a variety of different delivery platforms. Moreover, MPEG2-TS was developed specifically for broadcast. ATSC 3.0 relies on IP protocols, which may be advantageous in interactive use cases. Recognizing this, DVB, too, has several specifications intended for IP-based transport.

A LOOK AT AV CODING TECHNOLOGIES

For advanced video coding, ATSC 3.0 solely relies on HEVC, while DVB-T2 offers the flexibility to use HEVC or MPEG-4/H.264, lowering equipment cost thanks to minimal patent licensing fees. Both ATSC 3.0 and DVB-T2 allow broadcasters to deliver all video resolutions, from SD to UHD (4K), along with providing advanced features like High Dynamic Range, High Frame Rate, Wide Color Gamut and Next Generation Audio to enhance the viewers’ experience.

For subtitles, both ATSC and DVB use XML based solutions. DVB also has a widely implemented solution for bitmap-based subtitle delivery, which remains the preferred approach globally today.

CONTENT PROTECTION DIFFERENCES

Content protection is a key requirement today, especially for premium content like live sports and movies. A major difference between ATSC 3.0 and DVB-T2 is the method of content protection used. ATSC 3.0 relies on the MPEG Common Encryption (MPEG-CENC) scheme. It’s a perfect solution for delivering video protected by DRM over a broadband network to connected devices. The drawback: it is not specified for a broadcast-only environment, meaning most pay-TV use cases are left in the dark.

Conditional access (CA) is the heart of DVB-T2 content security, with support for Simulcrypt. This approach allows broadcasters to use different CA solutions. In addition, DVB also supports Multicrypt where all CA related functionality is implemented in one CA Module, separating the TV functions from the CA functionality. To make this approach work, DVB has specified the Common Interface (CI) between the TV set and the CA Module. This Interface is mandated in the European Union.

Overall the DVB CA approach is very successful; about 50% of all DVB receivers worldwide are used for pay TV.

INTERACTIVE SERVICE CAPABILITIES

According to Strategy Analytics, there are 1 billion connected TVs in homes globally. Given the nature of smart devices in use, today’s television viewers expect an interactive experience, with access to broadband and video content. Both ATSC and DVB-T2 (via HbbTV) support interactive service delivery. The major difference is that HbbTV has been established across Europe and other parts of the world, whereas ATSC 3.0 is still rather new. While trials are underway, it does not yet have an ecosystem for interactive applications and services.

In today’s connected world, interoperability is important. HbbTV provides a test suite so that devices, and suppliers of hardware and software components, can confirm compliance with HbbTV specifications. Having a test suite is an absolute must for delivering compliant and interoperable solutions.

CONCLUSION

ATSC 3.0 and DVB-T2 are both state-of-the-art digital television systems with advanced features like interactivity. The main technical differences lie in the transport mechanisms (IP for ATSC 3.0 vs. MPEG2-TS for DVB-T2) and content protection schemes (MPEG-CENC for ATSC 3.0 and CA/Simulcrypt/Multicrypt for DVB-T2) used. Ultimately, DVB-T2 has successfully been deployed by multiple countries across Europe, serving a combined population of more than 3.5 billion, meaning it has an established and proven ecosystem. Moreover, DVB-T2 is closely aligned with the wider set of DVB standards, supporting satellite, cable, IP and terrestrial delivery, whereas ATSC 3.0 only covers terrestrial use cases, limiting its appeal for those looking to implement digital television services.

Peter Siebert is the head of technology at DVB.

For a comprehensive source of TV Technology’s ATSC 3.0 coverage, see ourATSC3 silo.

LAS VEGAS--As Yogi Berra might have observed about this year’s CES, “It was déjà vu all over again,” (at least with regard to the next-gen TV sets being displayed by both large and small manufacturers.)

Last year, with the ink still drying on the 3.0 standard and the FCC’s green-lighting of its use by the nation’s TV stations a couple of months earlier, ATSC, NAB and CTA industry officials gathered to celebrate its arrival with a champagne toast on the opening day of the CES. However, there was not a single 3.0-capable set to be found among the super-bright, super-big, super-colorful, super-intelligent, (and, in some cases, super-expensive) television receivers that literally reached the ceiling of the Los Vegas Convention Center which hosted the 2018 show.

Fast forward a year—has there been any change in the 3.0 situation?

In a word, no! If anything, there was less ATSC 3.0 presence this time, as one TV manufacturer did put up a sign in its 2018 CES display space that touted the benefits of the new DTV transmission standard. Not even the sign was there this time.

CRITICAL MASS

While most of the TV set exhibitors quizzed about the lack of ATSC 3.0 product (which has been available since 2017 in South Korea) were silent about its absence at CES, John Taylor, senior vice president of public affairs for LG USA did offer an explanation.

“You’re a year or so early,” he said. “We’re trying to time the introduction of the product with the critical mass of Next-Gen TV broadcasting, and the whole industry seems to be moving toward a 2020 product launch.” Taylor did seem fairly certain that the 3.0 sets would be populating manufacturers’ exhibit spaces at the 2020 CES to “prime the pumps” of buyers who would be at that show to decide what to stock their stores with for the 2020 holiday buying season.

And while others in the industry have hinted that there may be a problem with delivery of some of the components needed for 3.0 sets, Taylor was quick to state otherwise.

“There’s no technology issue at all,” he said. “It’s a business marketplace consideration about the right time to introduce the product in the U.S. market. We could ship the product today. As you know, we’re shipping ATSC 3.0 TVs in Korea, but it has to make sense for the U.S. market and that’s heading towards 2020.”

Taylor noted that LG and its Zenith R&D subsidiary are providing receiver products and technical support for some of the U.S. ATSC 3.0 field trials.

THE VIEW FROM OVERSEAS

Peter Siebert, head of technology for the DVB (Digital Video Broadcast organization, a Swiss-based consortium that sets digital broadcast transmission standards for Europe, and is roughly the equivalent of the Advanced Television Systems Committee), was at the show and had a slightly more pessimistic view when asked about the appearance of ATSC 3.0 TVs at the 2020 edition of the “world’s biggest consumer electronics show.”

“I don’t think so,” said Siebert. “And the reason why I don’t think so is that there has to be a strong commitment from the broadcasting community to say ‘we will introduce the service,’ and personally from a European perspective, I don’t hear this message from the North American broadcasters.

“It’s a typical ‘chicken and egg’ problem and there must be somebody breaking it,” he continued. “The broadcasters must say ‘we offer a service.’ It doesn’t help that the industry develops products first. For example, when I look at the televisions, there are many 4K televisions on the market. However, this doesn’t mean that we have 4K broadcasts. I think the broadcaster has to make a firm commitment to introduce the service and then the receiver industry will follow.”

Siebert noted that when the United Kingdom decided to migrate from the original DVB-T (terrestrial broadcast) standard, which was struck in 1997, to an updated version, DVB-T2, which was completed in 2008, there was no “chicken and egg” situation because there was a clear commitment from the BBC for a rollout of the improved HD service via DVB-T2.

“It can go very fast if well planned,” he said, noting that the transition was accomplished in Ukraine in a single year and in two years in Germany. Siebert did admit that the move to DVB-T2 didn’t go quite so fast in every European nation, explaining that “typically, the more a country is relying on terrestrial television, the longer it takes, because you have a much bigger legacy of receivers that you have to update before you can start a new service.”

However, lack of suitable receivers didn’t seem to be an issue in the DVB-T2 transition.

“In Germany, when we went from DVB-T to DVB-T2, we had all stakeholders sitting together at a round table and making a plan on how to introduce T2,” said Siebert. “It was very clear. The broadcasters said on this date we will switch our transmissions to the new DVB-T2 specification. And it was also very clear that the consumer industry [would be] ready way before this, providing the necessary equipment. So, at the time the switchover happened, quite a high percentage of receiving equipment was ready. I think it is necessary that all stakeholders sit together, to agree on a plan and then stick to the plan.”

THE VIEW FROM SINCLAIR

Since ATSC 3.0’s inception, one of its biggest backers has been the Sinclair Broadcast Group, and for the past several years the broadcast station group has been at CES to promote the standard, even operating a transmitter on Black Mountain south of Las Vegas to provide TV set exhibitors with 3.0 signals to demonstrate reception of OTA UHD video at the show. Sinclair has also hosted demonstrations of 3.0 technologies a few blocks away from the convention halls in a suite at the Wynn Hotel.

Mark Aitken, Sinclair’s vice president of advanced technology, was on hand this year to offer his take on the absent ATSC 3.0 hardware.

“I think it’s very simple,” said Aitken. “There two issues. The difficult one is content protection, and this issue has not been answered. You’ve got a lot of dancing around on the part of the networks with respect to what their requirements are for content protection, and not a single solution that has been put on the table has been supported by all of the content providers—and I might add content distributors or MVPDs. So, you have a bit of a stalemate. For me, it’s a fairly easy one to resolve. I look at it and say as a starting point ‘if Widevine [DRM] is good enough for Netflix, why isn’t it good enough for broadcast?’

“The networks will always try to extract the broadcaster from out of the middle of the relationship with the consumer,” continued Aitken, noting that reluctance of networks and program providers to allow their content to be transmitted by affiliates deploying ATSC-M/H [aka Mobile DTV] was one of the reasons for that mobile initiative’s ultimate demise.

“I think there’s been a soft promise made on the part of broadcasters that we’re willing to come to a solution. There’s been an unwillingness on the part of the large content players to sit down and really try to solve that problem, at least with Sinclair. They have their own views and their views are not shared equally with all broadcasters. And so, for the very same reasons that we ended up with Dolby AC-4 as an abstraction of the Atmos production environment in Hollywood, the issue of content protection is being driven by those same Hollywood entities, which for a broadcaster is driven through the network.”

Aitken summed up the situation by stating: “It is a political problem, absolutely.”

Aitken said that Sinclair will light up 26 markets by the end of 2019.

“There’s a requirement by the FCC that there be some replication across ATSC 1.0 and ATSC 3.0,” he said. “There may have to be an opportunity to force that issue at a regulatory level, which nobody really wants. But at the end of the day sometimes you solve problems by spilling a little blood first.”

THE CHIP

Despite his disappointment with this stalemate in the rollout of 3.0, Aitken was in a celebratory mood as he announced the release of an integrated circuit specially designed and fabricated for Sinclair. The chip’s unveiling marked the end of a nearly two-year journey that began with a pledge to supply free ATSC 3.0 demodulator chipsets to any company manufacturing smartphones or other handheld viewing devices that would commit to including them in their products.

Explaining the genesis of the project, Aitken—who is a firm believer that broadcast television’s future lies in mobile devices—said that after surveying existing 3.0 chip products, he quickly came to the conclusion that none were really satisfactory for mobile device applications.

“We knew what sort of power the available chips consumed,” said Aitken. “It’s easy enough to guess the power requirement specs, because it’s almost like a curling iron if you’ve ever put your finger on one. If we were ever going to have a mobile-enabled device—something that was suitable for embedding in phones, something that could couple-up to a cellphone without draining the life out of the phone—we would have to create it.”

Frustrated that none of the large consumer electronics firms showed much interest in mobile TV products, he decided to go it alone.

“We went literally to the top of the ladder, and at the end of the day, they saw the world the way that they choose to see the world,” he said. “They saw no place for mobile ATSC; certainly not at this time.”

Aitken recalled an Indian company with a reputation for low-power consumption specialty integrated circuit design—Saankhya Labs—from his involvement with ATSC M/H—and contacted them.

“I decided to pick up the phone and have a conversation with Praag Naik, who is the president,” said Aitken. “We had a conversation, and it became evident that we shared a much higher-level understanding of what was possible, so Sinclair invested.”

The result was the creation of a very low-power consumption chip that can easily be incorporated within a mobile viewing device without substantially decreasing its battery life or increasing its physical profile.

NOT JUST FOR ATSC 3.0

Aitken said that as Saankhya had an established reputation in software-defined radio (SDR) technology, it was decided early on to create a chip that was signal agnostic, with software dictating which of a dozen or so digital TV signals it will decode, including ATSC 1.0 and the European DVB-T2 standard.

“We’re not building an ATSC 3 chip,” he said. “We’re building a chip that can go in set-top boxes, in televisions, in tablets, for any global broadcast standard, including digital radio. You level your risk by having a multistandard chip.”

Aitken says that at present about 1,000 of the chipsets have been created, and the foundry is ready to roll out millions more. Asked about takers for the free devices, he acknowledged that this has been a bit of a hard sell, but sees some light on the horizon.

“We’ve offered a major carrier five million chips. We’ve also offered the engineering of that chip into the device and we’ve offered the availability of the IP data stream, but that has not been enough to entice them to do that yet, but we are knee-deep into discussions with a USB manufacturer.”

Aitken views this as a first step to getting the chips into mobile devices, explaining that they would be part of a USB-C “dongle” equipped with an embedded antenna and designed to plug into mobile devices. And by the chip’s not being specific to ATSC 3.0, the dongle could be used virtually anywhere that digital over-the-air broadcasting is taking place.

“It would host DVB-T2, ISDB-T, ATSC 1, and other standards just by changing the software,” said Aitken. “It could be used in any part of the world.” 

For a comprehensive list of TV Technology’s ATSC 3.0 coverage, see our ATSC3 silo.