Sprint conspicuously absent from LTE-U debate

While the other big U.S. nationwide wireless operators have lodged their opinions in the great LTE-Unlicensed (LTE-U)/Licensed Assisted Access (LAA) debate, Sprint (NYSE: S) has been quiet on the topic. Of course, it's got plenty of other things going on, but the silence is somewhat curious because the company plays in both the Wi-Fi and LTE camps.

Perhaps that's the rub. The company wants to play it safe and let others duke it out, and it doesn't see itself adding any value in weighing in. Or, it's still working out its own internal debates. Either way, it's choosing to sit this one out, at least for now. The company has not publicly addressed LTE-U and related issues in the FCC's docket nor in other public statements.

That's not to say it isn't doing something. A while back, CableLabs asked the FCC for permission to use Clearwire's 2.5 GHz spectrum to test how LTE-U and LAA coexist with Wi-Fi networks. CableLabs said at the time that it had the blessing of Clearwire's owner, Sprint. CableLabs told FierceWIrelessTech that it wanted to move its research into a real world environment rather than inside labs.

While the cable industry has been extremely critical of the LTE-U efforts, I don't see Sprint's work with CableLabs as necessarily a sign that it's aligned with cable. There are more than a few ironies in the LTE-U debate. For example, Qualcomm (NASDAQ:QCOM) developed MuLTEfire for entities that do not have an anchor in licensed spectrum -- which includes cable companies -- yet cable companies are screaming foul at the notion of using a version of LTE in unlicensed spectrum because of their vested interests in Wi-Fi. 

LTE-U supporters Verizon (NYSE: VZ) and T-Mobile US (NYSE:TMUS) have been very clear in where they stand. Verizon formed the LTE-U Forum in 2014 with a group of vendors that included Ericsson (NASDAQ: ERIC), Alcatel-Lucent (NYSE: ALU), Qualcomm Technologies and Samsung, then shared their ideas with other operators. T-Mobile in particular showed an interest in backing their efforts.

As for its part, AT&T (NYSE: T) is not a member of the LTE-U Forum, and in its public comments in June, AT&T noted the two different versions of LTE unlicensed that are in development. It stated that LTE-LAA is being worked through the 3GPP standards process under Release 13 and will incorporate listen before talk (LBT) and other capabilities to ensure that LTE-LAA can coexist with other unlicensed uses.

The other version, "confusingly known as 'LTE-Unlicensed' or 'LTE-U' is a specification developed by the LTE-U Forum and uses a different mechanism to manage co-existence through an off-duty cycle -- carrier sensing adaptive transmission ('CSAT') -- between LTE and other unlicensed uses," AT&T said. "Unlike LTE-LAA, LTE-U is not a global solution because it does not implement the listen before talk mechanism required by other countries."

Sprint has a history of leveraging Wi-Fi, and it has called Wi-Fi the fourth layer of its network. Earlier this year it struck a multi-year agreement with Boingo Wireless to offload data traffic to Boingo's Wi-Fi networks at 35 major U.S. airports. The Boingo deal is just one element of Sprint's strategy to make Wi-Fi an integral part of its network as it strives to improve network performance. At the same time, Sprint launched Wi-Fi Connect, a consumer Wi-Fi router that prioritizes Sprint-specific Wi-Fi Calling over other Wi-Fi traffic and includes "smart connect" technology that dynamically manages 2.4 GHz and 5 GHz Wi-Fi bands for optimal Wi-Fi data performance.

As we all know, Sprint's got a lot going on in the network improvement department. During its second-quarter conference call, Sprint Chairman Masayoshi Son, who brought Softbank back from the brink in Japan, said "Japan has the best network in the world." When he visits the United States, he has found that "this network in this country is not something that you should be proud of. It is actually very bad. It's not just Sprint, even Verizon, AT&T and T-Mo, all network is pretty bad," he said, according to a Seeking Alpha transcript.

Sprint is working with Softbank engineers in Japan to apply some of what they've learned to the U.S. network. Softbank and Sprint both have 2.5 GHz spectrum, and both are using TD-LTE on top of FDD-LTE. "So the common practice, common know-how, common technologies could actually apply," Son said. "So I am now very, very confident that Sprint will be able to create equal or better. In my view, it will be a lot better network very soon with much lower capex."

Sprint made a splash in Chicago this week with the revelation that it will bring 750 additional new jobs to neighborhoods throughout Chicago and expects to invest $150 million in the market by the end of 2016, up from a previous commitment to invest $45 million. Of course, Chicago is an important market for Sprint, as it's one of 80 markets where Sprint has started the deployment of two-carrier carrier aggregation in the 2.5 GHz band. Not surprinsingly, Sprint has made Chicago a showcase market for its technology and has deployed LTE Advanced capabilities such as 8T8R (8 Transmitters 8 Receivers) and multi-layer MIMO in the city, in addition to carrier aggregation.

Again, Sprint has a lot of work going on network-wise, but it seems that at some point in time, it makes sense to show its cards when it comes to LTE-U and LAA. It will be interesting to see what it does.--Monica

P.S. For a great rundown of Sprint's trials and tribulations, check out FierceWireless contributor William Ho's latest column.