Qualcomm CTO thinks LTE-Unlicensed and Wi-Fi can coexist peacefully, targets mid-2016 for LTE-U phones

BARCELONA, Spain--Qualcomm (NASDAQ:QCOM) CTO Matt Grob said LTE-Unlicensed (LTE-U) can easily coexist with and protect Wi-Fi operations in unlicensed spectrum, similar to how different variants of Wi-Fi already perform today. He also said that he thinks commercial handsets that support LTE-U could be in the market by mid-2016.

Carriers and vendors here at the Mobile World Congress trade show have disclosed plans to push ahead with LTU-U trials and future deployments even in advance of finalized specifications from the 3GPP. However, a main concern from Wi-Fi operators and the larger Wi-Fi community is that LTE-U will overwhelm Wi-Fi and relegate it to being a second-class citizen in unlicensed bands.

In an interview with FierceWireless here at the conference, Grob said that he understood those concerns but said they are and will continue to be addressed by LTE-U proponents like Qualcomm and carriers like Verizon Wireless (NYSE: VZ) and T-Mobile US (NYSE:TMUS). After all, he noted, Qualcomm is a leading supplier of Wi-Fi products and technology as well.

"The last thing we want to do is anything that harms Wi-Fi," he said.

Grob noted that LTE-U, which might be deployed in the 3.5 GHz or 5 GHz bands, is analogous to new versions of Wi-Fi themselves, which have to coexist with previous versions. For example, he said, when the Wi-Fi community started out with 802.11 a/b/g protocols and introduced the more advanced 802.11n, it was not raised as a concern that 802.11n would crowd out earlier versions of Wi-Fi, and he said it was embraced because of the performance improvements the new version brought.

However, Wi-Fi proponents worry that the control and scheduling in LTE-U, which is sometimes referred to as Licensed-Assisted Access (LAA), will always be run over the licensed channel since it is centrally-scheduled, meaning that carriers will hold the balance of power over how much spectrum is devoted to LTE and how much to unlicensed Wi-Fi. The Wi-Fi Alliance urged caution and cooperation with Wi-Fi users in February.

"There is a risk that LAA, and especially pre-standard systems deployed ahead of coexistence work being done in the industry, will negatively impact billions of Wi-Fi users who rely on 5 GHz today for networking and device connectivity," the group said in a statement then. "It is generally agreed in principle that fair sharing is required, but there needs to be further work from all parties to address this risk in practice."

Grob said that was a valid concern but that some operators that are embracing LTE-U are using Wi-Fi to offload cellular data traffic. "What we're offering to the operators is a more efficient way to offload, which is really better for everyone," he said.  

Additionally, he said LTE-U first looks to finds empty channels to occupy, creating "no impact at all to anyone because you are using that which is not being used at all." When a channel gets fully congested, the LTE-U device, which has a Wi-Fi receiver built in, will engage in a practice known as "listen before talk" and if it hears any traffic "then it's not allowed to transmit."

"And that is exactly the same as the regulations require, depending on the region," Grob continued. "And that's exactly what the 802.11 family already does." He added that the two technologies can share spectrum for a variety of applications, including streaming video, file transfers and even real-time traffic like VoIP.

When LTE-U is in use it actually benefits Wi-Fi users, Grob said. "If even you have a single Wi-Fi user completely surrounded by LTE-U users, that single Wi-Fi user will actually perform at a higher level than if they were surrounded by lower-performing Wi-Fi users," he said. That's because LTE has a technology performance edge over Wi-Fi, and LTE modems are more sophisticated and contain more efficient scheduling technologies. Eventually Wi-Fi will improve and have these capabilities, too, Grob said.  Since LTE is around three times more efficient than Wi-Fi in some cases, Grob said, that makes Wi-Fi users have more spectrum to use.

LTE-U was recently renamed by the 3GPP as LAA to stress the point to government spectrum regulators that the use of LTE on a secondary carrier in an unlicensed band would be accompanied by a licensed primary carrier.

T-Mobile will be one of the first carriers to deploy LAA in 5 GHz spectrum in 2016, and is teaming up with Qualcomm and Alcatel-Lucent (NYSE: ALU) to use LTE in the unlicensed spectrum, with trials beginning this year using LTE-U enabled small cells from Alcatel-Lucent that are equipped with Qualcomm Technologies' FSM99xx family of small cell system-on-chip (SoC) solutions. Commercial products are expected in the first half of 2016.

Verizon earlier this year announced that it plans to deploy LTE-U technology in the 5 GHz and 3.5 GHz bands starting in 2016.

Grob said that those carriers' decisions to move ahead with LTE-U plans before the 3GPP has finalized LAA standards is "a decision they take balancing the interest of time to market and leadership there." He said Qualcomm is able to offer a version of LTE-U today that is derived from LTE Release 10 and that it does not prevent a carrier from completing a software upgrade when the final standard is published. Grob said that the so-called "Phase 1" pre-standard version of LTE-U is fully compliant with FCC requirements and "coexist very nicely with Wi-Fi."

Qualcomm will be making its chips available for LTE-U in the second half of this year for both devices and network infrastructure, and Grob said it "would seem reasonable" to expect to see commercial smartphones in the market supporting LTE-U by mid-2016.

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