As LTE Broadcast Tests Another Idea Bears Watching

    Transmitters will be accessible for use.

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    Rich Redmond chief product officer
    While LTE Broadcast tests are making headlines globally, there’s an intriguing concept quietly brewing under the surface.

    As mobile operators weigh whether to bet big on LTE Broadcast technology the challenges ahead may soon prompt many to take a hard look at an altogether different approach to mitigating the impact of video consumption on their network resources.

    Amid much publicity surrounding the launch of LTE Broadcast tests worldwide, there’s another idea percolating below the radar promoted by broadcast transmitter supplier GatesAir which could offer a lower cost and faster path to broadcasting popular content to mobile users.

    The concept, soon to undergo testing in Paris, entails use of broadcast TV transmitters operating in the UHF band to transmit LTE as well as TV signals, thereby avoiding use of the LTE infrastructure to enable bandwidth-saving point-to-multipoint distribution of live programming to mobile customers.

    Critically, the LTE-delivered content flow is not tied to the TV broadcaster’s content in the UHF TV tower broadcast model.

    Mobile operators will be able to use the transmitter to deliver whatever content they may license for broadcast distribution, irrespective of which TV channel is being broadcast from the same radio.

    The huge difference between the two approaches starts with the fact that a mobile operator can reach an entire metro area with point-to-multipoint content delivered from a single broadcast transmitter.

    Recent statements from top mobile carrier executives and a flood of press releases have put LTE Broadcast, formally known as evolved Multimedia Broadcast Multicast Service (eMBMS), in the limelight at a moment when it’s far from clear how long it will take before the ecosystem essential to making eMBMS a core component of mobile video service strategies materializes.

    eMBMS capabilities must be embedded in device chipsets, which means carriers will have to cycle through the current generation of smartphones and other mobile-connected devices before there’s a mass market base for eMBMS.

    Verizon Wireless, which has publicly affirmed deployment of eMBMS across its entire LTE footprint, plans to begin introducing LTE Broadcast service by the second quarter of next year, when the carrier anticipates enough devices will have eMBMS-capable chipsets to represent a meaningful target base.

    Most of the smartphones now sold in Verizon stores are equipped with LTE Broadcast chipsets, the company says.

    But the real benefits of LTE Broadcast, beyond early uses for minimizing congestion in stadiums and other closed environments when most people will have their devices tuned to the same live video coverage, are tied to reducing congestion from live program streaming over the wide area mobile network, which will require a mass market base.

    Moreover, there is a significant licensing issue when it comes to distributing live premium content ubiquitously over a mobile carrier’s footprint.

    AT&T chief strategy officer John Stankey during an appearance at the Oppenheimer Technology, Internet & Communications Conference in August, alluded to the issue as he described AT&T’s intention to begin rolling out multicast capabilities on its LTE network in 2015.

    While  “customers want to be able to watch and entertain themselves wherever they are, under their terms,” Stankey said, “the reality of the industry today and how content is licensed and sold doesn’t fit elegantly into that model.”

    A more localized approach to mobile distribution of live TV programming may be less fraught from a licensing standpoint, especially if local broadcast stations were able to participate with a substantial upside to the business model.

    This is one of the benefits mobile operators could realize from pursuing the Tower Overlay mobile broadcast strategy proposed by GatesAir, formerly a unit of Harris Broadcast and now operating independently following the acquisition and restructuring of Harris by an investment team led by Charlie Vogt.

    Vogt, along with serving as CEO of Imagine Communications, the other piece of the Harris acquisition, is a member of the GatesAir board of directors.

    Speaking about the Tower Overlay solution when it was first announced in the spring, Vogt commented, “The broadcast model has always been the most reliable, scalable method for one-to-many delivery of high-quality video and audio, and the Tower Overlay model brings that same wireless spectrum efficiency to the mobile universe.

    This breakthrough innovation offers a compelling business case for broadcasters and mobile service providers alike.”

    Commercialization of the concept is a good 12 to 18 months away, according to Rich Redmond, chief product officer at GatesAir.

    But, in many respects, it may not have as steep a hill to climb as eMBMS. While the Tower Overlay strategy doesn’t begin to have the backing that eMBMS has in the mobile sector, it’s starting to catch the notice of major operators, Redmond says.

    “We’ve had some dialogue with AT&T and Verizon,” he says, noting interest is especially strong in Europe among the likes of Orange, Telecom Italia, Holland broadcaster NPO and TDF, a Paris-based provider of radio and TV transmission services.

    TDF and GatesAir are slated to launch a trial of the technology from the Eiffel Tower in January as part of TDF’s experimentation with various solutions offered through the DVB-T Broadcast Multimedia Mobile initiative.

    Tower Overlay, which is based on technology developed at the Technical University of Braunschweig’s Institute for Communications Technology in Braunschweig, Germany, is closer to commercialization in Europe owing to the fact that DVB-T2, the second-generation DVB standard for terrestrial broadcast, provides for what is known as Future Extension Frames (FES), which makes it possible to generate the LTE waveform from a broadcast transmitter without interfering with the primary DVB waveform.

    “Such capabilities are a focus of development of the ATSC 3.0 standard in the U.S.,” Redmond notes. “When everybody talks about next-generation ATSC, mobile is a big subject.”

    Development of ATSC 3.0 is well underway with multiple proposals for the physical layer of the standard now pending before the Advanced Television Systems Committee, including one jointly developed by LG Electronics, LG’s Zenith research unit and GatesAir known as FutureCast.

    The main thrust of ATSC 3.0 is development of support for Ultra HD, including use of HEVC compression and an over-the-air RF modulation technology, most likely OFDM (orthogonal frequency division multiplexing), that will enable higher bit rates than can be accommodated over 6 MHz broadcast channels with today’s HD-optimized ATSC standard.

    The chosen physical layer will also provide means of ensuring signal robustness, as is the case with FutureCast, which, among other things, uses an advanced forward error correction system to maintain signal quality.

    As demonstrated in a recent Madison, Wisconsin field trial of FutureCast over Quincy Group’s WKOW-TV outlet, the standard will likely support enough throughput per 6 MHz channel, topping 25 mbps, to support a 16 mbps UHD signal and a couple of lower bitrate streams to deliver high-quality signals to tablets and smartphones.

    The latest test, serving as a demonstration to the press, analysts and broadcasters, followed a larger-scale test in Madison this past summer where data from scores of reception sites, including challenging reception areas inside buildings, in fast-moving vehicles and at locations ranging from downtown to 50 miles from the transmitter, validated system performance.

    “Based on what I’ve seen in these FutureCast tests, the new standard will enable exciting new business models for broadcasters and exciting new services for viewers,” says Brady Dreasler, chief engineer for Quincy Group.

    FutureCast, it should be noted, as a physical layer proposed for all TV spectrum allocations, including VHF as well as UHF, is not in and of itself a permutation of Tower Overlay.

    The latter is designed to take advantage of the fact that certain LTE spectrum allocations reside in the general UHF region occupied by UHF stations, which, for one or the other application, extends from about 470 MHz to about 800 MHz.

    Thus, the content configured for reception on mobile devices by FutureCast is derived from the core TV channel being transmitted, whereas Tower Overlay allows the LTE broadcast to stream content independently of the TV channel.

    But what makes FutureCast or other proposed physical layers for the ATSC 3.0 standard important to Tower Overlay is the fact that most ATSC 3.0 proposals include provisions for FES.

    With FES as part of ATSC 3.0, which is likely to be very similar to DVB-T2 in other respects as well, the Tower Overlay will be able to work with UHF broadcasts conforming to ATSC 3.0 much as it has with DVB-T2 broadcasts, Redmond says.

    To make this possible, along with the FES component in ATSC 3.0, there will need to be what GatesAir and its allies refer to as an LTE-A+ expansion of the 3GPP LTE Advanced standard, which they are promoting within that body.

    This extension of the standard would make it easier for LTE-A+-compatible devices to adjust to the high-power transmission used with terrestrial broadcast.

    But there’s no need to add new radio receivers to the devices insofar as most LTE-capable devices are already equipped to interoperate in the UHF realm, although some models may not support some of the more recently added LTE spectrum slices, Redmond notes. “We’ll need some middleware signaling extension to the LTE standard, but there won’t be a need for new chipsets.”

    “We’re demonstrating this is a viable technical solution with significant business upsides for both the station owners and the operators,” he says. “From a wireless carrier perspective it’s like having a megacell to deliver your multicast signals across the local market.

    It’s a very flexible, cost-effective way to avoid overloading your existing LTE infrastructure.”

    Rather than dropping a lot of money on the network upgrades essential to getting LTE Broadcast off the ground, MNOs could take advantage of the shared radio resources to deliver whatever portion of the local live video traffic they might want to offload from their existing cell sites. “The big thing we see here is the carrier doesn’t have to bring spectrum or more hardware,” Redmond says. “They just pay for the use.”

    There’s no getting around the fact that there are significant hurdles to be cleared by both LTE eMBMS and the Tower Overlay concept.

    But it may well be that some carriers at least will find the latter strategy offers cost and business model benefits representing a better course.

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