LTE in Unlicensed Bands Explained

The adage that “everything I needed to learn, I learned in kindergarten” is true for LTE in Unlicensed Bands as well.

But first, what is LTE in Unlicensed Bands?

LTE in Unlicensed Bands is a new innovative feature in 4G/LTE wireless networks that uses unlicensed spectrum. Wi-Fi was introduced into unlicensed bands as a new service without government approval, and just like Wi-Fi, LTE in Unlicensed Bands is being developed through industry bodies. It has also undergone significant real-world coexistence testing that demonstrates it is a good neighbor that will not interfere with Wi-Fi.

Consumers will benefit from LTE in Unlicensed Bands with:

  • Better coverage;
  • Faster peak speeds;
  • Reduced latency (lag time); and
  • Smoother transitions between carrier networks and unlicensed bands.

Meanwhile, the mobile network operators that are already efficient spectrum users will be even more efficient thanks to this newly available technology.

So how is LTE in Unlicensed Bands like kindergarten?

Be polite.
Just like your teacher used to tell you (or your classmates) to be polite, do not interrupt and co-exist with others, LTE in Unlicensed Bands will listen before talking to prevent interference with Wi-Fi and other signals. This will allow a harmonious existence with other technologies.

Fair sharing.
Your teacher also probably said that sharing is nice, and that’s why LTE in Unlicensed Bands will “fair share” to accommodate traditional Wi-Fi signals and other unlicensed services.  

Unlicensed spectrum is a digital sandbox that enabled many great innovations and benefits for consumers across the country. LTE in Unlicensed Bands will provide consumers with even more opportunities for improved network coverage, speeds and experience.

LTE in Unlicensed Bands FAQ

What is LTE in Unlicensed Bands?
LTE in Unlicensed Bands was designed to use LTE technology, the primary and mainstream technology for commercial wireless operators, in the unlicensed band. It is an innovative technology that has unique algorithms for sharing with Wi-Fi and other technologies.

Will LTE in Unlicensed Bands interfere with my Wi-Fi service, such as my router?
No. The, LTE-U Forum and its members (i.e., Qualcomm, Verizon, Ericsson, Alcatel-Lucent, Samsung and LG) are sharing specifications and test results with the entire industry, including the Wi-Fi Alliance and its members, 3GPP, IEEE, Google, Microsoft, Intel, Cisco and Cable Labs to ensure it can coexist successfully.

But how do I know that LTE in Unlicensed Bands won’t cause interference? Give me the technical explanation.
The LTE-U Forum and its members are developing specifications to prevent any chance of interference with Wi-Fi while ensuring maximum consumer benefit.

There are three mechanisms to avoiding interference with Wi-Fi:

  1. The LTE in Unlicensed Bands small cell senses the nearby area and looks for a vacant unlicensed channel.
  2. If it cannot find one, it uses the least crowded by using a “Listen before talk” channel sensing capability called Carrier Sense Adaptive Transmission (CSAT). Then it takes turn with Wi-Fi users to enable successful coexistence.
  3. LTE in Unlicensed Bands uses an on/off routine to use the channel in a fair, proportionate share so it is vacated quickly. It’s never more than 50 milliseconds. It also has gaps that allow latency sensitive applications like VoIP, to not be impacted.

What testing has been done to ensure coexistence?
Through a rigorous testing process that tests real-world environments, LTE in Unlicensed Bands successfully co-exists with Wi-Fi as a friendly neighbor. The results of both the lab test results which replicate real world conditions is available from LTE Forum: PDF icon

Why do the carriers want to use LTE in Unlicensed Bands?
Spectrum, which fuels our mobile usage, is a finite resource. In order to maximize spectrum and ensure that wireless carriers can continue to meet Americans’ demand for mobile usage, it must be used fully.

Thanks to network engineers at various organizations, they figured out that LTE in Unlicensed Bands was a way to maximize spectrum that will benefit consumers.

How would LTE in Unlicensed Bands benefit me, the consumer?
You will enjoy better coverage, faster peak speeds, reduced latency (lag time) and smoother transitions between carrier networks and unlicensed bands.

LTE in Unlicensed Bands sounds great. When will it be available?
It will be available in the U.S. starting in 2016.

How does LTE in Unlicensed Bands differ from LTE-Licensed Assisted Access (LAA) and/or Standalone?
All three technological solutions recognize the ability to more efficiently use unlicensed spectrum and protect existing users. Operators and infrastructure vendors are all looking for the best way to serve consumers and enhance networks.

Both use a “Listen Before Talk” mechanism. LAA uses a different algorithm that is being standardized in 3GPP (release 13) and is expected to be deployed in Japan and Europe. Both of the versions coexist with Wi-Fi and the technology will continue to evolve over time.

There is a third version, which is a stand-alone version of LTE for Unlicensed. It does not use a licensed anchor, so it does not have the benefits of signaling and control on the licensed channel, but can fully operate in the unlicensed band and still be a good neighbor to Wi-Fi.

Last Updated: ​November 2015
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