Small cells

Qualcomm Aims MuLTEfire at Unlicensed Bands

As the US Federal Communications Commission (FCC) investigates LTE-Unlicensed (LTE-U) technology, Qualcomm has added a new dimension to the contentious debate over the use of unlicensed spectrum bands with the introduction of a new LTE-based technology that would allow anyone -- not just existing mobile operators -- to deploy LTE in unlicensed spectrum. (See Operators, Vendors Advise FCC on LTE-U.)

Qualcomm Inc. (Nasdaq: QCOM) introduced the technology concept, called MuLTEfire, in a blog post late last week, following a keynote speech delivered by Executive Chairman Paul Jacobs at the IEEE International Communication Conference 2015 in London, where he first mentioned the technology. Qualcomm also included the technology in its response to the Federal Communications Commission (FCC) 's request for comments on LTE-U.

MuLTEfire is a standalone LTE option for unlicensed spectrum. That is, it operates only in unlicensed spectrum and does not require an "anchor" in licensed spectrum. It also does not require a SIM card or mobile subscription to use the LTE service in some deployment scenarios, such as at sports or entertainment venues.

This is significantly different from the other options for LTE in unlicensed bands, LTE-Unlicensed (LTE-U) and License-Assisted Access (LAA), which both rely on licensed spectrum for operation.

As such, the new technology potentially opens the opportunity for cable operators, Internet service providers or even large venue owners and enterprises to deploy their own LTE equipment in unlicensed bands, namely the 5GHz band, to provide mobile services. (See T-Mobile Expects LTE-U to Feature Listen-Before-Talk and Qualcomm Brings LTE-U to Small Cells .)

Want to know more about 4G LTE? Check out our dedicated 4G LTE content channel here on Light Reading.

But like LTE-U and LAA, MuLTEfire will also need to prove that it will be a good neighbor and not degrade WiFi performance in the 5GHz band. Qualcomm says it has tested features that can ensure the coexistence of LTE-U/LAA and WiFi without adversely affecting WiFi, and that MuLTEfire will implement similar coexistence features. (See Why Some Operators Think LTE-U Is Rude, NTT DoCoMo, Huawei Prove LTE-U Works and Ericsson Preps LTE-U for Verizon, T-Mob & SK Telecom.)

MuLTEfire is also an attempt to make LTE small cells as easy to deploy and operate as WiFi access points. According to Qualcomm, MuLTEfire will provide "LTE-like performance benefits to more deployment scenarios with Wi-Fi-like simplicity -- a leaner, self-contained network architecture that is suitable for neutral deployments where any deployment can service any device."

Qualcomm noted in its FCC filing that the licensed-anchor versions of LTE (LTE-U and LAA) will be more robust than MuLTEfire because they use licensed spectrum to handle operations including control signaling, mobility, registration, access and acquisition, whereas MuLTEfire will use unlicensed spectrum for everything -- data, signaling and all other operations.

A boost for small cells
Qualcomm claims the technology will "create expanded opportunities for small cell deployments, especially in hyper-dense environments and indoor locations."

The announcement was certainly a hot topic of discussion at the Small Cell Forum's timely workshop on "Small Cells and License Exempt Spectrum" on Friday in London. Of particular note for some at the workshop was the notion that MuLTEfire technology could be deployed by venue owners or enterprises in neutral host scenarios.

According to Mark Grayson, distinguished consulting engineer at Cisco Systems Inc. (Nasdaq: CSCO), speaking in his role as vice chair of the Small Cell Forum's network group, the Forum is looking at how to accelerate multi-operator capabilities, particularly for venues where "people are reluctant to deploy small cells."

He pointed out the stark contrast between 176 million WiFi access points deployed worldwide and 11 million small cells. "We need to talk about the multi-operator challenge to make small cells more relevant to the venues and businesses to get more [small cells] deployed," he said.

Qualcomm's MuLTEfire proposition appears to address this. According to the vendor, the technology will enable service providers or venue owners to "provide nomadic wireless access services to any end user (no subscription or SIM required)." And for mobile operators, Qualcomm says the technology can also provide new data offload opportunities.

"The biggest potential [for MuLTEfire] is about the venue owner," said Professor Simon Saunders, co-founder and director of technology at consultancy firm Real Wireless, speaking at the Forum workshop. "LTE can be a technology like WiFi."

Qualcomm's new technology doesn't make the unlicensed spectrum debate any less contentious, but it does create the potential for many more types of service providers to deploy LTE in unlicensed bands.

— Michelle Donegan, contributing editor, special to Light Reading

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Buyer18519 8/4/2015 | 12:40:47 AM
What Benifits compared to WiFi I didn't read any benefits compare to 802.11ac. Compared to 802.11ac Wave 2, with Mu-MIMO, We are talking about 866Mbps to 1732 ( 160Mhz ) bandwidth. Comparing to MuLTEFire 600Mbps.
MordyK 6/18/2015 | 2:02:05 PM
Re: LTE in Unlicensed Bands Totally agree! Basically any large scale managed network can benefit by being part of the LTE family instead of Wi-Fi. That said the royalty issue would need to be drastcially reduced, which is something that Qualcomm can easily do as it is a large collector of these royalties for LTE.
Gabriel Brown 6/18/2015 | 4:03:55 AM
Re: LTE in Unlicensed Bands In principle, the automated sign-on will help (although arguably you have that now with Hotspost 2.0 / Passpoint). But you would still need and account, or your operator would need a roaming agreement, with the private LTE operator. 

I can imagine this scenario working well in public access WiFi areas, such as airports, where the wholesaler will have multiple roaming deals.

Another area I think will be interesting is private 4G enterprise networks. 
MordyK 6/17/2015 | 2:47:41 PM
Re: LTE in Unlicensed Bands I can't see that happening, although anything is possible. The FCC is actually attempting the reverse, which is to find and open more spectrum for public use.
MordyK 6/17/2015 | 2:44:08 PM
Re: LTE in Unlicensed Bands There are tons of reasons why they contiinue to fail, but I think usability is a big issue. An LTE based system would resolve many of these and benefit from the work operators are doing to improve reach, reliability and capacity. Just think about the benefits at cell's edge over those of WiFi, where the limited range means your almost always bumping up at the edge.
kq4ym 6/17/2015 | 9:58:08 AM
Re: LTE in Unlicensed Bands I'm wondering though if the use of the currently unlicensed bands might expand so much eventually, that the FCC can then change the rules and bring those frequencies into licensing requirements. And how much Qualcomm and others may have to take that into consideration when ramping up their technology?
Gabriel Brown 6/17/2015 | 7:10:51 AM
Re: LTE in Unlicensed Bands Yeah, could be. Muni WiFi in general has been a (predictable) dissappointment* for well-known reasons. Low power output and high frequency are part of the problem. It's not clear unlicensed LTE will help all that much in the Muni WiFi case as it is subject to the same constraints. We'll see.

* I expect there are some success stories as well.
MordyK 6/17/2015 | 5:06:38 AM
Re: LTE in Unlicensed Bands Gabriel, All those points are valid concerns and there's plenty of work and lobbying aimed squarely at those issues. The point I was trying to make is that if everything works well technically and its approved, it would then be super cool as an improved alternative for Muni Wi-Fi.
Gabriel Brown 6/17/2015 | 3:46:22 AM
Re: LTE in Unlicensed Bands Mordyk -- leaving aside the WiFi co-existence question, one of the challenges in this "muni" scenario is the co-existence between unlicensed LTE access points owned by different operators running in a shared band. LTE was designed to work in licensed spectrum for the exclusive use of one operator. Almost by definition, high density urban locations will require more than one operators, and thus listen-before-talk will be needed.
Gabriel Brown 6/17/2015 | 3:40:33 AM
Re: Don't forget the $40 royalty fees Claus, your point on the actual adoption rate of LTE-U, LTE-LAA, and LTE Unlicensed, is a good one . A minor bump in performance is unlilkey to swing the decision.

If you think of LTE as a co-ordinated system, and that an LTE device typically has better receive sensitivity than WiFi, there should be some gains, but are they sufficient?

Qualcomm talks about LTE-U providing 2x to 4x throughput gain compared to WiFi, and that it actually improves WiFi performance at the same time. This is disputed and, obviously, Qualcomm has a vested interest in making it look good, but there's something there. WiFi people don't really want to acknowledge any performance gain.

Meanwhile, there's a counter opinion on co-existence in this white paper from Google:

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