Wi-Fi backers warn about unlicensed LTE while Ericsson claims speed boost

The Wi-Fi Alliance warned that LTE on unlicensed frequencies could interfere with Wi-Fi and said it plans to collaborate with the 3GPP cellular standards group to help prevent that.

Mobile operators are starting to explore the use of the unlicensed 5GHz band for LTE even though many Wi-Fi networks rely on those frequencies. On Tuesday, Ericsson announced it’s testing unlicensed LTE with Qualcomm and that SK Telecom, T-Mobile USA and Verizon are interested in the technology.

Most countries set aside large portions of the 5GHz band for use without a license, and Wi-Fi has become a major user of that spectrum. Mobile operators are allowed to use the band even though they have their own licensed frequencies, but LTE wasn’t developed to coexist with other networks in that kind of environment.

The 3GPP is developing protections for other users of the spectrum under the banner of LAA, or License-Assisted Access. However, LAA is part of an update to the LTE standard that’s not due to be finished until the end of this year. That worries the Wi-Fi Alliance.

“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 5GHz today for networking and device connectivity,” the Alliance said in a statement on Monday.

The Wi-Fi and LTE industries have to work together on a fair way to share the band, the Alliance said. It plans to collaborate with the 3GPP and with anyone planning a pre-standard deployment to help make sure Wi-Fi users aren’t hurt.

Meanwhile, Ericsson said it’s running live tests of LAA in its labs in conjunction with Qualcomm, which demonstrated the technology last month at International CES. The tests at Ericsson Labs in Sweden and Canada showed LTE networks getting a speed boost of as much as 450Mbps (bits per second) by combining licensed and unlicensed frequencies, Ericsson said. That was achieved with commonly used amounts of spectrum: 20MHz in a licensed band and 40MHz in unlicensed.

The technology they tested also enables fair sharing of spectrum between LTE and Wi-Fi, Ericsson said.

In a press release, three major mobile carriers voiced varying degrees of interest in the Ericsson-Qualcomm tests. South Korean SK Telecom said it achieved the trial with Ericsson and Qualcomm and would continue to work with them on advanced technologies. T-Mobile, which has said it plans a trial deployment later this year, and Verizon also called the tests encouraging.

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