Did you know that WiFi could disappear?

Mobile network operators are constantly developing new techniques to provide better quality of service to their clients, but resources and specially the spectrum, are limited. One option that has been studied since last year is the named LTE-U (LTE Unlicensed). However, as we will see later, companies frequently discuss if this will be a real benefit for the user or it will be a problem for users with WiFi at home. Why? Would it be a real problem?

LTE-U is a new multi-band wireless communication system initially promoted by Ericsson (known as the Licensed Assisted Access-LAA) that aims to re-use the 3.5 and 5 GHz bands to provide high speed LTE connectivity.

Figure 1. LTE-U and WiFi coexistence
In theory, the basic LTE-U protocol shouldn’t be a problem because is based on the “listening before transmitting” protocol; first, it looks for free channels in the 5 GHz band avoiding the ones used by WiFi connections. However, a study carried by theSignal Research Group (SRG) in collaboration with Verizon Wireless and Qualcomm tested an LTE-U version by making different VoIP calls and Voice over WiFi at the same time that LTE-U and WiFi traffic were active.
Figure 2. WiFi and LTE-U study

The results weren’t 100% positive and because they found that including LTE-U is similar to add a new Access Point to the channel, which isn’t convenient in high loaded WiFi networks.

In addition, Google, Microsoft and Comcast published the possible risks of using LTE-U showing that the standard will be promoted by the mobile network operators only due to commercial interest. However, almost at the same time, Huawei and NTT DoCoMo published the results of tests carried in dense user spots, using LAA and WiFi, and they proved that this combination is positive; the reason is that, unlike LTE-U, LAA is supported by the 3GPP, which make it more compatible with WiFi. Therefore, the dangers come from the competition between WiFi and LTE operators.
CableLabs is a a consortium funded by various cable and WiFi companies and they also have get involved in this issue: they have tested LTE-U and WiFi coexistence in their offices and they published that “WiFi performance suffered disproportionately in the presence of LTE-U”.
Figure 3. CableLabs published results, screenshot
But they not only found a throughput degradation, the tests showed that there is a significant impact in latency:
Figure 4. WiFi and LTE-U latency
In addition to WiFi, LTE-U and LAA, MulteFire is another technology recently developed taking advantage of the un-licensed spectrum in order to provide more capacity. There are different opinions about the coexistence of these technologies. The most positive one comes from the Qualcomm infographic that shows some “guide lines” to make these technologies coexist together:
Figure 5. Screenshot of Qualcomm’s infographic
More recently, in the last Mobile World Congress, the Senza Fili Consulting President, Monica Paolini also talked about the relevance of this topic:

MWC2016: Monica Paolini talks LTE-U, LAA

To conclude, let’s just mention that the amount of wireless clients in the United States is three times bigger than the broadband cable clients, and wireless growth as well as the mobile devices sells are increasing more and more. What do you think? Is LTE-U a new technology developed for the users’ benefit or is it just a new business strategy from mobile network operators?

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