Alan Weissberger Wireless

Clearwire and Sprint ask 3GPP for TDD-LTE U.S. std in 2.6GHz band


Clearwire and Sprint are part of a group of operators and vendors that have asked the 3rd Generation Partnership Project (3GPP) standards body to start work on specs that would allow TD-LTE to be deployed in the US in the 2.6GHz spectrum — which is now used for mobile WiMAX in the U.S.  The actual 3GPP contribution had many authors, with Clearwire, Sprint listed 1st (China Mobile also listed).

For more details on this move, please see:

This is really not a surprise, even though IEEE 802.16m (WiMAX 2.0)  standard is close to being completed.  My opinion is that Clearwire will continue with its 802.16e CLEAR rollouts this year and net (if they get additional funding). In 2011-2012, they will evolve their network to LTE-TDD (rather than IEEE 802.16m). Sprint is behind this strategy as they own approximately 52% of Clearwire and resell CLEAR as a MVNO.

 Here is a key section of the 3GPP co-authored contribution:

3GPP™ Work Item Description

For guidance, see 3GPP Working Procedures, article 39; and 3GPP TR 21.900.

Title: LTE TDD in 2600MHz for US (Region 2) (Core)

The purpose and objectives of this work item are:

  • Study LTE TDD in 2600MHz band for deployment in US, generating a new technical report based on study results. The specific band to be studied is 2496 to 2690MHz with TDD channel arrangement for the US and region 2 only.

(AW note: Clearwire holds large amounts of spectrum in this band)

  • Develop channel arrangements using existing LTE channel bandwidths (such as 5, 10, 15, 20MHz) that take into account the nature of the FCC regulations (such as 5.5 and 6MHz channels, 16.5MHz blocks, etc)
  • Add the necessary changes to the relevant core requirements to support LTE TDD in the 2600MHz band as identified above. Note that it is not expected to have new demodulation performance requirements.

One of my conclusions was that this probably means we can kiss WiMAX 2.0 (IEEE 802.16m) goodbye.   We wonder what Intel's response will be?  All the other major WiMAX chip vendors have announced plans to also support LTE.  Can Intel be that far behind them?  I sent this mail to the IEEE ComSoc Discussion group and received quite a few replies.

IEEE ComSocSCV Discussion Group member  took  issue with my conclusion and wrote, "not so quickly, please."

"Clearwire (like any good business) is protecting its options..Clearwire wants this work item to included in the 3GPP new features.

Look at the WiMAX MS chipset ecosystem, it is large and healthy where the cost of a WiMAX chipset is lower than 3G chipset,

What will be the price for LTE, actually who are the Tier 1 semiconductors other than QCOM and STE can develop a LTE chipset?

Will LTE-TDD chipset prices be equivalent to WiMAX or equivalent to 3G or even lower!

This LTE-TDD is an important feature overseas and just complements WiMAX 16e."

Another Discussion list member wrote:
"I hear so much propaganda on LTE vs WiMAX. But reality is that only WiMAX is actually delivering on the promise of fast mobile internet connectivity speeds. All the LTE promoting 3G operators are busy deploying HSPA or HSPA+ or EVDO technologies and figuring out ways to offload their 3G data traffic to WiFi networks to save their networks, instead of deploying technologies like WiMAX that actually serve the user needs better than 3G. VZW and ATT have LTE plans that are still in the works and nothing significantly threatening to the WiMAX deployments in the US. Real end user experiences between WiMAX and LTE will be so similar that one would even wonder what are all these propaganda bits about. Especially some take information and blow it out of proportion."

Of course, we are not predicting that IEEE 802.16e based mobile WiMAX deployment will stop anytime soon., it is important to note that there is currently no TDD-LTE standard in the requested band (2496 to 2690MHz), so a network buildout using that modulation and duplexing scheme won't be ready anytime soon. It is at least two years away, in my opinion.  That is the timeframe when WiMAX 2.0 is scheduled to be available, but we don't see any market traction from network operators or chip companies in that space.

More articles documenting the TDD-LTE (AKA TD-LTE) movement:

In mobile tech war, LTE haunts WiMax again

TD-LTE: The most powerful weapon in the LTE arsenal against WiMAX

Russia's Yota says 'did not vow to use WiMax'

Sprint and Clearwire Among Time Division-LTE Proponents

Future merger of LTE and WiMAX into a single 4G standard isn’t as far-fetched as it once seemed

Author Alan Weissberger

By Alan Weissberger

Alan Weissberger is a renowned researcher in the telecommunications field. Having consulted for telcos, equipment manufacturers, semiconductor companies, large end users, venture capitalists and market research firms, we are fortunate to have his critical eye examining new technologies.

6 replies on “Clearwire and Sprint ask 3GPP for TDD-LTE U.S. std in 2.6GHz band”

Great article with a lot of insight and acumen. Here's a follow on from Fierce Wireless:

That move is not surprising given Clearwire CEO Bill Morrow's statements during the CTIA Wireless trade show last week. He again reiterated that Clearwire is open deploying LTE when the technology catches up to WiMAX and called for one standard down the road.
The proposal has been accepted by the 3GPP just as TD-LTE has begun heating up around the world, with China Mobile the most anxious to deploy the version in the 2.3 GHz band. WiMAX technology is designed to operate in the TDD band. Motorola has said that several operators around the world are also interested in the version because of the lack of paired spectrum in some areas. Qualcomm is looking to deploy TD-LTE in India if it wins a license at auction there.
In addition, broad industry support for TD-LTE in the 2.6 GHz band came from Sprint Nextel, NII Holdings, China Mobile, UK Broadband, Motorola, Huawei Technologies, TD Tech, WiChorus, ZTE, Chinese Academy of Telecommunications Technology, Nokia Siemens Networks, Cisco Systems, Sequans Communications, Alcatel-Lucent, Alcatel Shanghai Bell Co. and Rohde & Schwartz.

Read more:

Gary Kim of TMCNet says "LTE has won."
Whether that is an attempt to leverage some technology aspect of the Chinese air interface, or simply a face-saving mechanism allowing Clearwire to say it has not adopted LTE as used by virtually all other mobile operators in the world, is unclear.
What does seem clear is that the speed advantage once touted by WiMAX backers has largely been lost.
According to Clearwire, WiMAX should give users between 3 to 6 megabit per second access, with bursts of around 10 megabits per second. But even versions of 3G technology, namely HSPA-Plus, can do that, and more.
Verizon's LTE network, being built this year, will exceed those speeds, routinely running in the 7 Mbps to 12 Mbps range.
Clearwire recently asked the 3GPP to set standards for TD-LTE to be operating in the 2.6 GHz band, which Clearwire uses. Currently TD-LTE is only working on the 2.3 GHz band.
The 3GPP said that they’ll start working on Clearwire’s request, and that by March 2011 the standard should be ready. Clearwire, by contract, can’t make the switch to another mobile broadband technology until November 2011.
It may well be true that Sprintand Clearwire had no choice but to launch with WiMAX, since LTE was not yet as advanced in the standards process. But the request for a version of LTE Clearwire can deploy in 2011 seems an indication that the original gamble is not working out.
Some will continue to maintain that "both" LTE and WiMAX are key 4G platforms. That's true, but misleading. LTE has won.

The key question for me is what will Intel – the world's number one WiMAX cheerleader- due now that there are apparently so many defectors from WiMAX to LTE (e.g. Nokia, Alcatel-Lucent, Cisco, etc).  Will they be the last WiMAX man standing?

In the article, I state that it will take at least two years for TD-LTE to be deployed in the U.S.  According to Scott Walters, Clearwire cannot make a formal switch until November 2011 when its contract with Intel expires for WiMax.  Here's the link to Scott's article:
On a separate track, we hear that the upcoming India BWA auctions (in the 2.3 and 2.5GHz band) will be won by bidders like Qualcom, which plan to deploy TD-LTE rather than WiMAX
If WiMAX does not make it in the potential high volume Indian market, then how can it achieve critical mass for device and RAN equipment makers?

At his Oct 27 Sprint Developers Conference keynote, CEO Dan Hesse was asked about Sprint's plans for LTE.  He answered that Sprint and Clearwire collectively have enough spectrum to support both from the same cell tower.  In other words, the existing or soon to be "4G" (Mobile WiMAX) customers would not be abandoned.  However, Mr. Hesse did not address the need for Mobile WiMAX to LTE interoperability and coverage.  In particular, will new buildouts be WiMAX, WiMAX and LTE, or LTE only.  If they are anything but WiMAX/LTE, then dual mode devices will be necessary to access the broadband wireless network.

Despite many articles like this one – pointing out that IEEE 802.16e-2005 is NOT 4G- all the head honcho Sprint speakers referred to their mobile WIMAX service as "4G."  Dan Hesse said yesterday, "We were the first carrier to roll out 4G service in 2008."    At an earlier session, I asked a question referring to Mobile WiMAX rather than 4G, the Sprint presenter said, "Oh, you're using the trade name for our 4G service."  I had to bite my tongue to remain silent.

Another issue is that Sprint does not give Clearwire credit for building out their "4G" network.  At this conference, CLRW was seldom mentioned in the "4G" Sesssions or in general sessions where "4G" was discussed.

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