Editor's note: Over the next several editions of RF Update, Broadcast Engineering will present the perspective of various RF vendors on the issues likely to be making news at the 2011 NAB Show.
Mobile DTV and how to deal with its many ramifications will likely be hot-button issues for many television broadcasters at the 2011 NAB Show, says Scott Barella, vice president of technology and business development for LARCAN.
While he hasn't yet seen a stampede of broadcasters to launch mobile DTV service, Barella says several interlocking technical issues related to the new service will be widely discussed at the show. Among the most important will be the relationship between quality of service delivered and the revenue model employed for mobile DTV; power efficiency, the future of the Big Stick and distributed transmission via a single-frequency network; and a growing chorus of broadcasters who will question the fairness of being forced by the government to restrict mobile DTV modulation to ATSC A/153 rather than having the freedom to deploy CMMB, DVB-T2, or some other mobile standard.
To Barella, the quality of service broadcasters seek to achieve with mobile DTV will depend on how important it is to them that they protect the content they are delivering. "Subscription, advertising or a combination of both will determine the mechanism of capital expenditure for RF when it comes to mobile," he says. Mobile DTV deployment based on a subscription model may require broadcasters to add a higher level of RF redundancy — particularly if they want to deliver five nines reliability consumers expect from other subscription services like mobile phones.
But quality of service issues don't end with redundancy, he says. Ultimately, broadcasters looking for a way to reach subscribers in the concrete canyons of downtown areas, sitting in arenas, traversing transit tunnels and in other troublesome spots will consider deploying single-frequency networks to augment their Big Stick. As they do, says Barella, they likely will explore whether it makes sense to reduce power out of their Big Stick in favor of powering up a network of low-power transmitters in an SFN.
While these issues will be front of mind for many broadcasters at the 2011 NAB Show, they likely will be overshadowed by the bigger concerns raised by the Federal Communication Commission's National Broadband Plan and its implications for mobile DTV, says Barella. Increasingly, broadcasters will ask why they are being asked to relinquish spectrum rather than being given the freedom to employ other modulation techniques, such as CMMB or DVB-T2, that could position them to deliver free-to-air TV and meet the goals laid out in the National Broadband Plan, he says.