5G and ATSC 3.0: The New Hybrid?

Will the newest crop of wireless standards—ATSC 3.0 and 5G—foster more hybrid solutions to remedy the seemingly ceaseless spectrum demand for wireless-data transmissions?

Those who depend on the airwaves must find more efficient ways to use that finite resource or risk diminishing revenue-generating services or narrowing public safety systems because of a resource crunch. Recent actions to provide more of this resource for unicast transmissions warrants a thoughtful consideration of hybrid-system solutions.

The latest transfer of U.S. spectrum licenses to the wireless telephone carrier industry occurred in 2017 when the Federal Communications Commission (FCC) auctioned 70 MHz of spectrum from the 600 MHz band used primarily by the terrestrial broadcast TV market. Next up will likely be parts of the C-band satellite, or mid-band, spectrum. That will be used for unicast transmissions that deliver the highly popular on-demand content that has fueled the smartphone era. The delivery method is also an inefficient way to transmit bandwidth-hungry entertainment content (especially video).

As spectrum assignments have been shifted, development of the next-generation wireless telephony and digital TV systems has occurred, and both systems have “greater efficiency” credentials. Those credentials are legitimate but it’s likely that eventually they will be insufficient as super high-definition video and audio, virtual reality, IoT, massive multiplayer videogames, torrents of software for operating sophisticated vehicular systems, and other bandwidth-hungry wireless applications are cultivated.

How does spectrum use become more efficient? Cultivation of new technologies is an obvious answer, such as advances in transmission, antenna, high-frequency band use and compression technologies, among others. Those advances are typically funded by industry, and each industry segment naturally concentrates improvements that builds on its legacy systems. This perpetuates a rigid system where nearly all data is transmitted in accordance with that industry segment’s methods—regardless of whether that is the best method for all types of data. This leaves little room for distribution cross pollination.

A recent report from the Cellular Telecommunications Industry Association (CTIA) says it has achieved great strides in efficient U.S. spectrum use through transitioning from one iteration of 3GPP standards to the next generation of standards. Indeed, iterative standards improvements over the last three-plus decades have delivered greater efficiencies. The study also claims the “quick deployment of newly acquired spectrum” as a hallmark of more efficient spectrum use. It’s not clear, however, how using newly acquired spectrum licenses (i.e., the 70 Mhz from the 600 MHz band) is equated with using it more efficiently. The argument can be made that the transfer is a step backward in advancing efficiency since it will be used for fundamentally inefficient unicast distribution.

So, if the transmissions are so much more efficient then why do the wireless carriers continue to request more spectrum? In large part, demand for the more inefficient point-to-point wirelessly delivered pictures, video and audio (aka data) to smartphones and other devices has soared.

That point-to-point transmission is wildly popular. And why not? On-demand viewing anywhere has transformed the TV viewing experience. Convenience is the new gold standard.

Terrestrial broadcast standard ATSC 3.0’s claim to good spectral citizenry is that it enables a significantly greater amount of data/content to be transmitted in the same 6 MHz spectrum channel as the current system. Better modulation and a leap from MPEG-2 to HEVC video encoding are the primary improvements. The mixture of efficient broadcast (point to multipoint) transmissions and the ability to deliver content over the Internet once received by a broadcast receiver gives the new system its hybrid cred.

Iterative standards improvements in the broadcast TV world have been slower than in the wireless telecommunications world. Because of the recent worldwide erosion of spectrum access for TV broadcasters, concentration on efficiency isn’t a “nice to have,” but a necessity.

Concentration on technological advancements is only part of the solution. The simple concept of transmitting data using the method most appropriate to the content’s purpose can also be part of the solution. Using capacity for unicast delivery of constant-bit-rate, high-resolution video to an audience of one may not be the best use of that capacity.

The not-so-radical idea of offloading appropriate data/content from unicast to broadcast networks is one whose time has come. Making that happen involves the equally difficult task of convincing TV broadcasters and wireless telephone unicasters to form partnerships to that end.

Some popular thought is that a future 5G ecosystem will sufficiently satisfy the world’s voracious appetite for all wirelessly delivered data/content. We’ll find out in the next 10 years or so as 5G gradually builds up to mass deployment. In the meantime (and in the future), perhaps distributing data by the appropriate transmission method will make for the best use of that valuable and finite spectrum.