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Mapping 4G network for LTE video requires not just speed but backhaul

As wireless operators tap into the benefits of Long-Term Evolution (LTE), video delivery to mobile devices embodies the raison d'âtre for next-generation networking as well as its greatest challenge. But LTE is one part of the anatomy, which needs to be supported by strong network design.

No carrier is building a 4G network just for voice and text. As operators tap into the spectral efficiency, lower latency and higher data rates of Long-Term Evolution (LTE), video delivery to mobile devices embodies the raison d'âtre for next-generation networking as well as its greatest challenge. But LTE radio base stations are just one piece of the LTE video puzzle. A strong LTE backhaul network design is also critical.

 If you don't have the right pipes connecting that base station to the packet core, then it doesn't matter if [the radio network] is LTE or not.
Stéphane Téral
Principal AnalystInfonetics Research

"[LTE] is not the only thing you have to consider. You have to design an entire network -- not just the radio part of the network," said Stéphane Téral, a principal analyst at Infonetics Research. "If you don't have the right pipes connecting that base station to the packet core, then it doesn't matter if [the radio network] is LTE or not."

Engineering strong, conservative LTE backhaul will be the key to supporting LTE video, Téral said. Carriers with fiber in the ground all the way to the cell site will be in the best shape, he added.

"Just work with your backhaul -- because if the backhaul is not in place, then all the traffic is going to get stuck at the base station," Téral said. "AT&T has a big problem with backhaul because of the history of telecommunications in the United States…. In California, you deal with copper all over the place."

Carriers test LTE video, but tight-lipped on results

Japanese carrier NT DoCoMo appears to be the first carrier with an LTE-ready handset, which manufacturer NEC will demonstrate by streaming high-def LTE video at Mobile World Congress in Barcelona, starting Feb. 15.

Video is expected to make up two-thirds of the 39% increase in global mobile broadband traffic between 2009 and 2014, according to a Cisco Systems study to be released at Mobile World Congress. North American carriers are testing LTE video, data and voice and have slated deployments for the end of 2010 through 2011.

"Orchestrating the mobile network for voice is one thing … but video changes everything because it is not only bandwidth-sensitive but latency insensitive. You don't want to lose frames. You don't want jitter," said Kittur Nagesh, director of service provider marketing at Cisco. "LTE on the radio side moves us substantially forward … [but] you never have enough spectrum on the wireless side just because of the way radio waves work."

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With the theoretical potential to reach up to 100 Mbps downlink and up to 50 Mbps uplink, LTE meets the speed demands for mobile video, and many carriers have trumpeted their "successful" tests using the 4G technology for high-definition streaming video.

But when contacted to further discuss their network engineering strategy for LTE video, representatives from Verizon Wireless, AT&T and Bell Canada clamped up, citing competitive concerns. Other carriers that are planning LTE deployments did not respond to requests for interviews.

Cox Communications announced last week that it completed LTE video and voice tests in Phoenix and San Diego, but it declined to discuss the results or its strategy for next-generation networking.

When reached for comment, representatives for the cable company -- which plans to launch 3G wireless services in March through a partnership with Sprint Nextel Corp. as it builds its own 4G network -- said the carrier was keeping its LTE video plans "close to the vest."

"They're all crunching the numbers," Téral said. "No one really knows what's going to happen to the networks…. There are so many options [for next-generation networking] that it becomes difficult [for carriers] to make a decision."

To deliver mobile video, LTE far from the only option

Despite the buildup around LTE, video can be delivered to mobile devices via other technologies that don't require such drastic capital expenditures, Téral said.

"There are other tricks that we are discovering to lower the cost of an LTE network," he said. "It's by boosting the power of a 3G network and delaying the full-blown footprint of an LTE network."

Smaller overseas carriers -- including Telstra in Australia, NTT DoCoMo and eMobile in Japan, Sonaecom in Portugal, and mobilkom in Austria -- have had luck with video inside the 3G realm by moving to HSPA and HSPA+, which reach theoretical max. 42 Mbps speeds.

If carriers already have a robust backhaul design in place, and speed is the main issue for delivering mobile video, LTE is not the only option, Téral said. Carriers that use GSM can achieve somewhat higher speeds through software upgrades -- around 40 Mbps -- he added, if they want to avoid investing in new hardware designed for LTE.

"Latency is an issue [with video], so when you want to fix it, you look at your ammunition, and in the GSM world, you have plenty of ammunition with HSPA … and you can boost the bit rate by doing software upgrades," Téral said. "But there is no consensus on whether or not it's better to go to LTE and skip HSPA+…. If [carriers] need to deploy new hardware, it may be better to go to LTE and stay there."

Although  WiMax has not been the popular 4G option, it came to market faster than LTE, and Sprint offers it in 27 markets. Last month, the carrier launched its "Overdrive" router, which can create a 3G/4G mobile hotspot that can be linked to anything embedded with Wi-Fi, including Blue Ray players and video-game consoles.

In addition to use in the consumer space, Sprint's 4G network and its portable 3G/4G routers are used by police in Annapolis, Md., for remote video surveillance, according to Sprint spokeswoman Stephanie Greenwood.

"We certainly do expect video to be one of the primary uses for 4G," she said, "whether it be streaming video, even HD quality, through your TV or laptop … or a businessperson participating in a video conference or using another real-time streaming video application."

Let us know what you think about the story; email: Jessica Scarpati, News Writer

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