OnQ Blog

How to make the best use of unlicensed spectrum, LTE-U or Wi-Fi?

Feb 19, 2015

Qualcomm products mentioned within this post are offered by Qualcomm Technologies, Inc. and/or its subsidiaries.

Is it cliché, if I answer “both?” Whether it is or is not, “both” is the correct answer for many operators. Don’t believe the people who say it otherwise, at least we don’t. If you are wondering “why, how, and what gives? then keep reading—those are the exact questions we pondered and found answers to. 

For operators, the key to making the best use of unlicensed spectrum lies in one of their prized possessions: licensed spectrum. Kid you not, when you combine the unlicensed spectrum with the licensed spectrum, magic happens, providing a seamless user experience, better capacity and coverage—all with the convenience of a unified network.

OK, now, let’s see… what kind of combining or aggregation, as we call it, makes sense, and in where? Surprisingly it is very simple: if you are looking to leverage your existing or new carrier Wi-Fi (operator Wi-Fi) networks using 2.4 and 5 GHz bands—then opt for LTE Wi-Fi Link Aggregation. I know, quite a mouthful, but very easy to understand: you take LTE in licensed as the anchor and the link from Wi-Fi Access Points (AP) and aggregate them at the device. 

With LTE Wi-Fi Link aggregation (please somebody come up with one of those cryptic acronym that mobile industry is famous for), operators will be able to not only connect those Wi-Fi hotspots to LTE network but also their resources managed by LTE. Best of all, these Wi-Fi and LTE APs don’t have to be collocated, which means once this feature is available in the devices, operators can get going pretty quickly without major changes to the existing LTE and Wi-Fi networks. As mentioned, the actual aggregation happens in the device, deep-down at the modem level for maximizing the performance. And you know who makes the best LTE/Wi-Fi converged modems, don’t you?

On the other hand, if you are planning to deploy new small cells, you could do even deeper integration through traditional carrier aggregation, by bringing LTE into unlicensed spectrum (LTE-U). Wherein the small cell will use LTE for both licensed and unlicensed spectrum in the 5 GHz band, aggregating them at the device. I say deeper integration because it’s the same technology, same network, and same small cells just using different spectrum bands. Hence it provides better performance as well. But note that LTE-U is for only new small cells deployments, using 5 GHz spectrum. 

Now you get why I say “both” and not “either or” right? These options are suitable for different scenarios, and are purely based on what assets operators have. In many cases, both will exist even in the same network.

This is all good and well you say, but what about LTE-U sharing 5 GHz spectrum with Wi-F? Will that be fair? Can that be fair? Those are some questions we asked ourselves, before we embarked on the LTE-U mission. We wouldn’t be here if that was not the case. But I know you want proof, and I have it. Here’s the catch: you have to read about it in my next blog.

Before I go, allow me to ask that if you only remember one thing from this blog post, let it be: “LTE Wi-Fi aggregation for carrier Wi-Fi, LTE-U for small cells, LTE anchor for both.”

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Prakash Sangam

Director, Technical Marketing