Is License-Assisted Access Needed?

Some carriers are eyeing the use of LTE in unlicensed 5GHz spectrum as a way to keep up with skyrocketing capacity demands, but the technology isn't an ideal solution.

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The unquenchable thirst for more wireless speed and capacity is a major problem for mobile network operators today. As the latest 802.11ac wave 2 WiFi technology approaches theoretical speeds in excess of 1Gbps, LTE technologies are quickly falling behind. Part of this has to due with pure logistics in terms of upgrading an entire LTE network in a timely fashion. But much of the problem rests on the fact that more and more mobile devices are using the same, constricted licensed spectrum.

One solution that some carriers are looking into is the idea of leveraging unlicensed spectrum in the 5 GHz space -- the same spectrum where 5GHz WiFi resides today. The technology is known as License-Assisted Access (LAA) or LTE-Unlicensed (LTE-U), and it’s being backed by multiple wireless vendors and carriers around the world.

But just because the technology is gaining in popularity with mobile carriers doesn’t mean it’s a good thing for consumers or enterprise IT departments. So the question is, will LAA-LTE solve the problem it was intended to fix?

An organization known as the 3rd Generation Partnership Project (3GPP) is the primary group spearheading LAA development. According to its website, the initial goal is to develop “Licensed-Assisted Carrier Aggregation operation to aggregate a primary cell, using licensed spectrum, to deliver critical information and guaranteed Quality of Service, and a co-located secondary cell, using unlicensed spectrum, to opportunistically boost data rates.”

In other words, use small LAA cells that adhere to unlicensed transmit power/gain restrictions and backhaul that traffic over privately licensed LTE spectrum. This essentially clears up a great deal of congestion on carriers' licensed spectrum by offloading edge devices to the unlicensed 5 GHz space.

My first reaction is that this is a terrible idea that will further crowd an already crowded 5GHz unlicensed wireless spectrum. WiFi and LAA are also two completely different protocols and there is major concern that LAA won’t play nice in regard to sharing the waves with WiFi networks. While mobile network operator tests claim that LAA operates with little interference of neighboring WiFi networks, other analysis shows just the opposite.

Additionally, current LAA technologies can’t overlap in the same wireless spectrum. That means only one carrier can be present in any given physical location.

If we give LAA and its spectrum sharing capabilities time to mature, it's possible that we could have a time where WiFi and multiple  carriers using LAA can coexist in the same spectrum with out stepping on each other’s toes. But keep in mind that this would only be for a fixed period of time. And each time a new WiFi or LAA technology gets updated, there would be extra work involved to ensure that both technologies could cohabitate. Ultimately, this means extra time spent certifying new specifications, which would ultimately slow down the standardization and deployment of both protocols.

On the other hand, if LAA did take off, there would be certain cases where a carrier’s wireless network could be leveraged as opposed to installing and maintaining a private WiFi network. If speeds were comparable, and security/direct LAN access wasn’t a concern, some IT departments might forgo designing and deploying their own WLANs and instead use the carriers' LAA network. Small remote sites and storefronts that offer public/free WiFi are just two ideas where this might be an option.

T-Mobile is the first US-based mobile carrier to announce their plans to launch LAA sometime this year, but having a network ready to go means nothing without mobile devices that contain LAA-compatible wireless radios. That’s going to take a great deal of time, if it happens at all. So it’s going to be quite a while before we can see the true power of this technology in a real-world scenario.

It’s clear why mobile operators want to push forward with LAA.. The more customers use their network, the more they pay. Most wireless data contracts contain restrictive bandwidth caps. And if we leverage LAA instead of connecting to a WiFi network, the carriers stand to make more money on our overage charges.

Overall, considering the proliferation of private, public and even mobile carrier-grade WiFi networks, I don’t see a tremendous need for LAA at this point in time. That may very well change in the future. But for now, let’s hope that LAA stays out of our 5 GHz WiFi spectrum. Yes, we do need to figure out a solution to improve LTE speed and capacity moving forward, but this technology doesn’t fit the bill.

About the Author(s)

Andrew Froehlich, President, West Gate Networks

President, West Gate Networks

As a highly experienced network architect and trusted IT consultant with worldwide contacts, particularly in the United States and Southeast Asia, Andrew Froehlich has nearly two decades of experience and possesses multiple industry certifications in the field of enterprise networking. Froehlich has participated in the design and maintenance of networks for State Farm Insurance, United Airlines, Chicago-area schools and the University of Chicago Medical Center. He is the founder and president of Loveland, Colo.-based West Gate Networks, which specializes in enterprise network architectures and data center build outs. The author of two Cisco certification study guides published by Sybex, he is a regular contributor to multiple enterprise IT related websites and trade journals with insights into rapidly changing developments in the IT industry.

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