Thirty-six companies have weighed in on LTE-Unlicensed following the FCC's request for comment last month, some extolling the benefits of the technology, but many warning of the potential for interference with WiFi.

LTE-Unlicensed (LTE-U) refers to running LTE in 5GHz unlicensed spectrum for a speed and capacity boost. Vendors like Ericsson AB (Nasdaq: ERIC) and Qualcomm Inc. (Nasdaq: QCOM) are pioneering the technology for eager operators like Verizon Wireless and T-Mobile US Inc. But much of the industry remains unconvinced -- despite reassurances and lab trials -- that LTE-U won't interfere with the WiFi devices that have been happily occupying the 5GHz band in the US for some time now. (See Ericsson Preps LTE-U for Verizon, T-Mob & SK Telecom, NTT DoCoMo, Huawei Prove LTE-U Works and Why Some Operators Think LTE-U Is Rude.)

In Europe, it is mandated that LTE-U include a listen-before-talk (LBT) protocol from 3rd Generation Partnership Project (3GPP) 's LTE Release 13, which would ensure that the two networks play nice, This, the Licensed-Assisted Access (LAA) variant of LTE-U, is not required in the US, South Korea, China or India, causing many to fear that early deployments here won't bother to respect WiFi at all. (See Qualcomm Brings LTE-U to Small Cells .)

That is why the Federal Communications Commission (FCC) put out a public notice detailing its concerns on the technology and requesting industry comments. The comment period ended on June 11, with 36 companies, individuals or groups contributing feedback. The FCC is expected to suggest rules and regulations soon, based on this feedback. (See T-Mobile Expects LTE-U to Feature Listen-Before-Talk.)

For more on LTE-Unlicensed, visit the Carrier WiFi content channel here on Light Reading.

Most of the comments filed with the FCC recognized the benefits of LTE-U -- spectral efficiency, faster speeds and cost-effective capacity gains -- but also expressed concerns that it had to be implemented fairly and without harming operators' existing investments in WiFi. Many also called on the FCC to leave it to the standards groups to figure it all out.

Here is a sampling of the comments the FCC received on the matter:

In addition, Light Reading caught up with Broadcom Corp. (Nasdaq: BRCM), which also filed comments with the FCC, last month. Mike Hogan, the chip vendor's ‎Senior Director, Small Cell & Fixed Wireless Access, told us that -- regardless of what the FCC recommends -- he believes LTE-U will take a lot longer to come to fruition than some operators are hoping. LAA may be ready by the time they are anyway.

"I think you have to be careful about what carriers aspire to do and what really happens," Hogan said. "It's one thing to take a public position and say they'll do it versus whether it pans out in volume shipments. What happens quite often in these debates is, you may wind up accelerating existence of robust, fair, 3GPP-approved LAA specs because of the presence of these LTE-U threats and statements by operators. It's more likely it will just accelerate LTE-LAA rather than create a market for LTE-U."

— Sarah Thomas, , Editorial Operations Director, Light Reading