TV broadcasting is ever changing, but TV RF transmission sector has remained relatively stable. Significantly higher efficiencies make the cost-effectiveness of replacing first-generation, high-power DTV transmitters attractive, especially as some of them are becoming outdated now.
Over-the-air television has come a long way, now capable of delivering HD content that actually looks better than what the compressed signal cable companies deliver. But in a world now dominated by mobile devices and second screens, and the advent of 4K content, the current over-the-air standard is quickly becoming outdated.
Recently, the Advanced Television Systems Committee (ATSC) adopted a standard for the next-generation broadcasting system called ATSC 3.0. It is capable of some impressive tasks, including broadcasting 4K content without the use of an outdoor antenna - immersive sound, device-waking emergency alert functions, hybrid broadcast-broadband functionality, and enhanced video and cached on-demand delivery, personalized service and configurations not yet imagined. This is the promise of ATSC 3.0, the broadcast media transmission standard in the works at the Advanced Television Systems Committee. The standard is on track to be completed and ready to roll around in 2017.
Routine transmitter replacement is common in TV stations when they need one. But now with ongoing changes where FCC repack, ATSC 3.0, and UHD are all lined up to bring in advance technology, TV RF transmission sector appears to be headed into a storm.
Game-Changing ATSC 3.0
ATSC 3.0 has turned out to be a multimedia standard that is capable of providing television, radio, and digital content. This makes it as potentially important to over-the-top media distribution as it is to broadcast television. Being that, the standard is IP-based and is going to use the latest-generation video coding technology; the over-the-air standard is going to be able to deliver 4K support from the beginning and 8K support later through extensibility. ATSC 3.0's enhanced video and audio capabilities initially received the most attention. Its 4K UHD resolution and high-dynamic range (whiter whites and blacker blacks), are enhancements that many observers think will have the biggest consumer appeal. It also enables geeky features like high frame rate, wide color gamut (richer, more saturated colors), and immersive audio.
ATSC 3.0 Offers Various Advantages over Other Standards
Antenna problem. With a big enough antenna installed high enough, TV signals can be pulled from more than 60 miles away. Problem is that nobody wants to install an outdoor antenna and snake cable to all of the television sets in their house. ATSC 3.0 changes that. While the logistics of the antenna are not finalized by any means, industry leaders have floated the idea of a small antenna that would plug into the back of a television through either an HDMI or USB port.
It is much easier to sell a consumer on a gadget that you plug into a port and automatically receive local channels for free after tuning the TV than convincing them to buy an antenna, find the perfect position for it, and hide the cords.
Broadcast to smartphones and tablets. ATSC 3.0 has the capability of broadcasting to smartphones and tablets while people are on-the-go. It would require smartphone manufacturers to get on board and allow their devices to broadcast the over-the-air TV signal, something they have not done with FM radio chips.
Flexible transmission. Replacing the current single-data rate with the option of using a high-capacity standard like 256-QAM for transmitting 4K UHD video while simultaneously using less capacious but more robust approaches for less demanding video and mobile programming, users can even create a multi-format radio service, for example. Broadcasting audio and video to mobile devices inherently requires more robust technology because of varying receive conditions and compromised antennas.
Channel bonding. ATSC 3.0 has the ability to combine data from more than one transmitter and operate it as if it was one higher-capacity station. Television broadcasters in the United States already use this for ENG video backhaul applications using multiple cellular telephone lines. One application would combine the excess data capacity of multiple stations to serve up file downloads (video, Internet-of-Things) in the market.
Single-frequency networks. Single-frequency networks (SFNs) can be used in urban or hilly and mountainous areas to fill in over-the-air coverage on a single channel. Ordinarily, the interference generated by two stations transmitting at close proximity on the same channel makes this impractical, but ATSC 3.0 incorporates technology to minimize this. Broadcasters can have the traditional big stick transmitting from the center of a coverage area while also using smaller directional transmitters that broadcast on the same channel, originating from the rim of a normal coverage area and pointing toward the center.
In addition to the development revenue potential of ATSC 3.0's interactive features, many broadcasters are interested in taking advantage of its flexible transmission system to attract revenue from new kinds of customers - those who use file transfers to complete video purchases or deliver Internet of Things software and firmware updates. Public broadcasters are pretty creative about using new development techniques, but the file transfer business is a new one. Stations will attract new customers through local and national collaborations that pool available spectrum.
Path to ATSC 3.0
From a broadcast engineer's perspective, the ATSC 3.0 transition is as simple as a software upgrade or exciter replacement. The problem is on the receiving end. ATSC 1.0 and 3.0 are incompatible.
Conversion available to consumers is through a set-top cable or satellite box. Viewers who subscribe to a multichannel video programming distributor (MVPD) will not be able to notice any quality difference with ATSC 3.0. Transmission of ATSC 3.0 requires more power output than ATSC 1.0 for equal contour coverage - how much more power depends on the payload. At the 19-Mb payload of ATSC 1.0, 3.0 power output required to match might be slightly less. As the bandwidth of an ATSC 3.0 signal approaches 60 Mbps, it takes more power output than 1.0 power output to match 1.0 contour coverage. 60 Mbps is sufficient to broadcast five HD channels using HEVC.
TV stations will need to purchase new components to enable their transmitters to work with the new standard. Those stations that wish to provide 4K UHD and other advanced features will incur additional capital expenses to upgrade their studios and master controls.
ATSC 3.0 is not backward compatible with the current DTV standard, so it will require consumers to buy new receivers or tuners.
Since it will not be possible to broadcast ATSC 1.0 and 3.0 on the same transmitter, it is proposed that a transition period will allow a simulcast of programming in the original ATSC on some transmitters and ATSC 3.0 programming on others. Broadcasters in each market will need to devise plans for some extensive channel sharing in which some multi-station transmitters use ATSC 1.0 and others transmit using 3.0.
Existing duopolies will find this easy, but other stations will need to forge new relationships. Over the longer term, these could grow into a data-pooling effort allowed by ATSC 3.0's channel bonding features. There is a good chance that public television might be at a disadvantage in developing these.
For consumers, the transition will be easier. Televisions bought during the digital transition include both analog and ATSC tuning capabilities. There is no reason why those purchased after the new standard is adopted cannot have both ATSC 1.0 and 3.0 tuners. Tuners for 3.0 can be built into HDMI dongle sticks or small boxes to provide access.
ATSC 3.0 wireless network antenna, essentially a standard home Wi-Fi router with an ATSC 3.0 and ATSC 1.0 tuner is already launched in the market. It has a built-in electronically steerable smart antenna that can distribute programming to multiple devices throughout a home.
The Future Is Bright
Work on the ATSC 3.0 standard is to be completed in early 2017. The transition to the new standard will be more transformative. It recognizes and embraces the world of multi-device, which provides the greatest prospect for public broadcasting's future. Since this will be rolled out contemporaneously with the post-auction repack, stations and governing boards need to think strategically about spectrum management - how to get the most mission value out of these new capabilities and how to manage associated costs.
Flexibility in service options is a keystone of the next-generation ATSC 3.0 DTV broadcast system, including the opportunity for terrestrial broadcasters to send hybrid content services to fixed and mobile receivers seamlessly - combining both over-the-air transmission and broadband delivery. Options such as multiview and multiscreen are also important, as is the option of choosing among standard definition, HD, and Ultra HD resolutions.
Although the ATSC 3.0 standard is meant to last, technology continues to advance and consumer demands will evolve in ways that are difficult to predict. As a result, methods must be included in the ATSC 3.0 standard to facilitate a graceful evolution from the initial technologies to newer, more advanced technologies that may be developed in the future.
Signaling is being developed that will permit new receivers to take advantage of new technologies when they are available. This signaling begins at the physical layer and extends through to the application/presentation layer. The physical layer will have a very basic, highly robust form of signaling that can indicate what technology is used for the physical layer itself. At a minimum, each layer will have the ability to signal what technologies are used in the layer above.
Signaling and announcement information will include the ability to indicate the capabilities necessary to successfully render services, with a distinction between those considered essential and those considered optional.
How long will it take for the industry and public to embrace ATSC 3.0? It would be as fast as possible if it were not for the incompatibility issue. When the changeover happens, it will change what TV stations do. Some of those changes will include new potential revenue streams having nothing to do with traditional TV programming. ATSC 3.0 is IP. It is a private, branded, network backbone.
With up to a 60-Mbps ATSC 3.0 payload, some broadcasters might be selling some bandwidth to non-TV users. TV broadcasters have the tallest towers, most powerful transmitters, and most thorough penetration of nearly any local RF signal short of AM-band radio. Many, including local fire and police communications, could benefit greatly from a DTV signal's blanket coverage.