Clearwire Paves Way for LTE in US

Clearwire LLC (Nasdaq: CLWR) is part of a group of operators and vendors that has 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 WiMax -- in a move that further exposes the operator's interest in the competing proto-4G standard.

The proposal to adopt the 2496MHz-to-2690MHz frequency band in the US for TD-LTE, which was first highlighted on the "LTE Watch" blog, was accepted at a 3GPP meeting earlier this month. The acceptance is significant because it will enable Clearwire and other spectrum holders to deploy TD-LTE, which is the time division duplex (TDD) version of LTE, in the US.

The move is the strongest indication so far that Clearwire is eying the proto-4G technology chosen by its competitors, AT&T Inc. (NYSE: T), T-Mobile US Inc. , and Verizon Wireless -- although they will deploy the frequency division duplex (FDD) flavor of LTE.

The development also comes hot on the heels of Clearwire CEO Bill Morrow's comments at the International CTIA Wireless 2010 show in Las Vegas last week about operators using the same technology sometime in the future. (See CTIA 2010: Hesse – LTE Will Be Bigger But We Are First, Clearwire Is a WiMax Company (For Now), and Clearwire Testing in Silicon Valley as LTE Looms.)

Power in numbers
Clearwire was not alone in asking for the 2.6GHz spectrum to be defined as a TDD band for LTE. Indeed, there was broad industry support for the proposal from other companies, including: Sprint Corp. (NYSE: S), NII Holdings Inc. (Nasdaq: NIHD), China Mobile Communications Corp. , UK Broadband Ltd. , Motorola Inc. (NYSE: MOT), Huawei Technologies Co. Ltd. , TD Tech Ltd. , WiChorus Inc. , ZTE Corp. (Shenzhen: 000063; Hong Kong: 0763), Chinese Academy of Telecommunications Technology , Nokia Networks , Cisco Systems Inc. (Nasdaq: CSCO), Sequans Communications , Alcatel-Lucent (NYSE: ALU), Alcatel Shanghai Bell Co. Ltd. , and Rohde & Schwarz GmbH & Co. KG .

Part of the 2.6GHz band is already specified for TDD, namely the 2570MHz-to-2620MHz band. The new work at the 3GPP will ensure that all of Clearwire's spectrum will have a definition for TD-LTE operation and will get the TD-LTE specs in line with Federal Communications Commission (FCC) requirements as well.

The specifications for the US 2.6GHz band for TD-LTE is scheduled to be completed by March 2011.

However, although the work at the 3GPP will make it possible to deploy TD-LTE at 2.6GHz in the US, Clearwire is committed to WiMax for now. (See Clearwire Can't Stray From WiMax 'Til 2011.)

"Clearwire intends to maintain our 4G leadership position, which requires us to future-proof our network and stay abreast of emerging 4G technologies and evaluate their potential when and if standards are reached," a Clearwire spokeswoman wrote in an emailed response to Light Reading Mobile.

Another boost for TD-LTE?
Beyond the implications for Clearwire's future network technology strategy, adding the US 2.6GHz band to the 3GPP LTE specs could potentially broaden the market for TD-LTE.

TD-LTE is the flavor of LTE that China Mobile will use, although it will deploy the technology at 2.3GHz. The operator is looking to gain support for TD-LTE outside China, so that it is not limited by low equipment volumes and relatively few device choices. (See China Mobile Fast-Tracks TD-LTE , Motorola's Shanghai Hope, China Mobile Selects Sequans for LTE Chips, and ZTE, China Mobile Test TD-LTE.)

For example, India has emerged as a new market for TD-LTE in the 2.3GHz band after Qualcomm Inc. (Nasdaq: QCOM) announced plans to participate in the upcoming spectrum auction in the country. (See Qualcomm Unveils LTE Plans for India, So Who's Pals With Qualcomm?, and India's WiMax Camp Wants Intel's Support.)

— Michelle Donegan, European Editor, Light Reading Mobile

COMMENTS Add Comment
hgmyung 12/5/2012 | 4:40:33 PM
re: Clearwire Paves Way for LTE in US

I appreciate your citing of my blog LTE watch as the source! This is an excellent in-depth article, by the way. - Hyung

kumaramitabh 12/5/2012 | 4:40:32 PM
re: Clearwire Paves Way for LTE in US The smoke is finally clearing on how mobile WiMAX ( specifically OFDMA-TDD) will be used in future mobile devices..or more precisely how the prime spectrum for WiMAX the 2.5 GHz band will be used.
Evan as the WRC07 had adopted OFDMA-TDD as one of the air interfaces which could be used in 3G networks, there were no 3GPP standards which would have permitted it. On the other hand the Mobile WiMAX itself has been handicapped in its use in mobile devices in the absence of full protocol stacks having been specified up to the application layer.
Now the smoke seems to be lifting as Clearwire has now asked the 3GPP to formulate LTE standards in the 2.5 GHz band.Unlike what one might expect, this decision will impact the use of 2.5 GHz spectrum worldwide even as 3GPP provides a standards support for new use of this spectrum.
Michelle Donegan 12/5/2012 | 4:40:23 PM
re: Clearwire Paves Way for LTE in US Good points. From US perspective, it certainly looks like Clearwire and Sprint and doing more than just thinking about TD-LTE.
Michelle Donegan 12/5/2012 | 4:40:23 PM
re: Clearwire Paves Way for LTE in US Thanks, Hyung!

It's an important development for Clearwire and for TD-LTE.

So, now I'm wondering about the likelihood of the IEEE and 3GPP working together on next-gen WiMax and LTE (802.16m and LTE-Advanced). Is there any chance of that happening?

hgmyung 12/5/2012 | 4:40:21 PM
re: Clearwire Paves Way for LTE in US

In my personal view, the chance of LTE and WiMAX being merged even in the future is slim. Technically, even though there are many commonalities between the two standards (OFDM, MIMO, all-IP architecture, etc.), the details, especially at the Physical Layer-level, are pretty divergent (ex. LTE uses SC-FDMA for uplink whereas WiMAX ODFMA). A harmonization may happen in the network level for seamless handover between the two networks but it's pretty much a dual mode type of service just done in a more efficient way. From this perspective, in order for a complete harmonization to happen, one camp pretty much has to dich their previous developments, which seems unlikely. From a political/market perspective, almost all major players in LTE are not active participants of WiMAX (Samsung is an exception), so there is usually some resistence towards WiMAX from the LTE camp. I think VZW CTO's comment during the recent CTIA Wireless 2010 in response to Sprint and Clearwire's call for LTE/WiMAX union (Clearwire CEO mentions that WiMAX could join LTE as one, Verizon Wireless CTO says no way) is somewhat telling of this sentiment. - Hyung

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