AT&T edging into LTE Advanced technologies for capacity, not speed

BARCELONA, Spain--AT&T Mobility (NYSE:T) plans to deploy elements of LTE Advanced network technology in order to increase the capacity of its network rather than increase the download speeds available to users, according to a top carrier executive here at the Mobile World Congress trade show.

Speaking at FierceWireless' "The Road to LTE Advanced" luncheon, AT&T's Kris Rinne said that AT&T will first deploy the carrier aggregation component of the LTE Advanced standard as it adds a second carrier to its existing LTE network. "We're not really changing the speed discussion," said Rinne, senior vice president of network technologies in AT&T Labs. "It's more about doing an efficient utilization of the spectrum."

Rinne said that users' peak speeds may increase, but AT&T is deploying the technology to ensure it can meet users' data demands as more customers start using LTE. She said the carrier's advertised data speeds likely won't change.

Rinne's position on LTE Advanced stood in contrast to that of SK Telecom. Alex Jinsung Choi, executive vice president and head of the South Korean carrier's ICT research and development division, explained that SK Telecom deployed LTE Advanced "to provide the maximum data rate for the end users." Earlier this month, SK Telecom said it will build out more 1.8 GHz base stations this year to provide 20 MHz of additional LTE bandwidth across South Korea and announced it is moving closer to rolling out a 10 MHz segment of the 2.1 GHz band that will enable it to provide 40 MHz of carrier-aggregated bandwidth. The operator said it eventually intends to use tri-band LTE Advanced carrier aggregation to combine 10 MHz in 800 MHz band, 20 MHz in 1800 MHz band and 10 MHz in the 2.1 GHz band.

Meantime, AT&T has said it plans to use carrier aggregation technology--which is part of the LTE Advanced specifications--to combine transmissions across its high-band band spectrum in either AWS bands or 1900 MHz with the low-band 700 MHz spectrum AT&T acquired from Qualcomm (NASDAQ:QCOM) in 2010 for $1.93 billion. AT&T's Unite hotspot, announced late last year, is the carrier's first device to support carrier aggregation technology.

According to speakers at the luncheon event, carrier aggregation is the first element of the LTE Advanced specification that carriers will deploy since it allows them to merge transmissions across disparate spectrum bands. Rinne said that, after carrier aggregation, AT&T will look to deploy LTE Advanced elements like heterogeneous networks (HetNets) and enhanced interference cancellation.

Interestingly, neither AT&T's Rinne nor SK's Choi would offer concrete comments on whether they would make use of unlicensed wireless spectrum alongside their licensed LTE networks. "It's definitely something we're looking at," Rinne said in response to a question about including unlicensed spectrum in AT&T's cellular network, but she added that the carrier hasn't made any firm commitments on the topic. Other speakers also passed on the question: "We don't have anything to announce," said Chris Pearson, president of 4G Americas.

However, Rasmus Hellberg, senior director of technical marketing for Qualcomm, said that "it makes sense to extend the benefits of LTE Advanced to unlicensed spectrum." He said Qualcomm is now working on technology to address this concept.

And what about 5G? The speakers agreed that there is no firm standard for 5G yet. "5G is not well defined," Rinne said, adding that "5G may be an evolution of the core architecture."

"It's basically a planning term right now to look at 2020 and beyond," Pearson concurred.

But SK's Choi said the operator will be looking at 5G options before 2020. He said South Korea will host the Winter Olympics in 2018 in Pyeongchang, and SK will likely want to show off 5G technology. "That kind of motivation leads us to look at some other innovative technologies," he said.

Related Articles:
Operators look to SK Telecom for LTE-Advanced leadership
SK Telecom closer to aggregating 40 MHz of bandwidth using three disparate spectrum bands
AT&T's Unite hotspot is the carrier's first device to offer carrier aggregation technology