Clearwire Chooses LTE Advanced

Posted by Sam Churchill on

Clearwire today announced it will add “LTE Advanced-ready” capability to its network. Clearwire said it will use Time Division Duplex (TDD) flavor of LTE-Advanced, a 100 Mbps 4G technology only now emerging from the labs. Here’s the transcript of the announcement by CEO John Stanton.

India and China may shape the LTE TDD ecosystem for the rest of the world, but Clearwire (and likely Sprint) now look positioned to be the LTE-Advanced pioneers.

The company ended the quarter with 7.7 million subscribers, after adding 1.54 million subscribers on a net basis. Clearwire expects to end 2011 with approximately 10 million 4G customers. Clearwire also reported quarterly revenue in the three months ending in June rose 176% year over year, to $323 million, yielding a net loss per share of 65 cents. That revenue figure includes $16 million in wholesale revenue that came out of Q1, and $13 million as part of a settlement with Sprint. Analysts on average were modeling $294.5 million and a net loss of 49 cents per share.

Clearwire will add “LTE Advanced-ready” capability to its network. It will require an additional $600 million in capital expenditures to deploy LTE, with a typical market overlay expected to be completed within 12 months from the beginning of deployment, reports Fierce Wireless. Clearwire will likely be the first commercial provider to offer the ultra high-speed mobile wireless standard.

LTE Advanced is an official “4G” standard. It’s defined by the ITU as delivering 100 Mbps (mobile) and 1 Gbps (fixed). Clearwire says it delivers download speeds in excess of 120 megabits per second, and will use it to augment densely populated areas of the market.

Time Division and Frequency Division flavors of LTE each have merits. But 2 X 20 MHz channels don’t grow on trees. Advantages of Clearwire’s LTE Advanced include:

  • Time Division is asymmetrical — better matching data traffic
  • One 20 MHz channel delivers 100 Mbps (mobile) in each sector
  • Inexpensive micro and pico cell relays can self-backhaul
  • TD-LTE is backed by China and India
  • Supports multiple carrier aggregation
  • Dual mode (LTE/WiMAX) chips and basestations readily available.
  • A world 4G voice/data standard on a world band (2.6 GHz).

Today Clearwire uses three different 10 MHz frequency bands on each of three sectors (30 MHz total). But the Wimax spec also allows re-use of the same frequency on each sector (10 MHz total). Clearwire may avoid the challenge of clearing new spectrum by splitting their current 30Mhz into two segments; 10 MHz for WiMAX and 20 MHz for LTE-Advanced. This architecture reuses the spectrum, which may have the effect of reducing WiMAX range and speed. If reception is poorer, then Clearwire may suggest a 4X MIMO LTE client, with better range and speed. All this may begin when clients and infrastructure that supports LTE Release 10 becomes available in a year or so.

Verizon’s LTE uses 10×10 Mhz of bandwidth. In contrast, Clearwire’s LTE Advanced will use 20 MHz of unpaired bandwidth. Time Division channels can be asymmetrical — better matching the needs of data-hungry users.

That could result in Clearwire delivering nearly twice the bandwidth (downstream) of Verizon’s LTE, for real-world speeds to the home of 20 Mbps. Think Voice over LTE. Even “wireless cable”. Verizon’s more widely spaced LTE cell towers may hit a capacity brick wall. Then what? In a competitive environment, jacking up overage fees won’t work.

It may not be all about raw speed. LTE-Advanced supports a hidden gem — micro and pico cell relays. Relays self-backhaul. They can be cheap and ubiquitous. Soon bus stops may sprout tiny LTE hotspots to fill in coverage gaps. LTE-Advanced also supports carrier aggregation from different carriers (pdf).

The 2.6 GHz spectrum is a 4G world band, and the world is going LTE. China and India are going TD-LTE. Clearwire (and Sprint) should fit right in.

Clearwire’s interim CEO, John Stanton, said the company will NOT use Sprint’s Network Vision architecture on its existing network, in order to save money, but is talking with Sprint to use it to deploy LTE in markets in which it has not yet deployed service. Currently, the vendors who supply WiMAX basestations for Clearwire include Motorola, Samsung, and Huawei. A card swap with software makes upgrading the Samsung and Huawei basestations easy.

Sprint’s Network Vision architecture will be supplied by Ericsson, Alcatel-Lucent, and Samsung, which will replace their CDMA and iDEN gear with new frequency-and radio-agnostic equipment. It will likely feature both WiMAX and LTE-Advanced on their 2.6 GHz spectrum. Sequans is working with Ericsson, Nokia Siemens Networks, Huawei, Alcatel-Lucent and ZTE on LTE interoperability.

Nokia Siemens Networks has been running TD-LTE networks for China Mobile and bought Motorola’s carrier business. The ease of LTE upgradability was enabled, at least in part, by Scott Richardson [then] Clearwire’s Chief Strategy Officer.

The 2.6 GHz spectrum in the US (pdf) is shared between Broadband Radio Services (BRS) and Educational Broadband Services (EBS). BRS spectrum (broadband wireless) is allocated according to Basic Trading Areas (BTA), of which there are 493 nationwide. The EBS spectrum is allocated with a center coordinate and a coverage area that spans 35 miles. Owners of Educational Broadband (mostly schools) paid nothing for this spectrum. It was originally targeted for educational television. Clearwire bought long term leases on the spectrum for WiMAX. Clearwire now has accumulated over 9000 licenses, with 100+ MHz typically available in the 2496 to 2690 MHz band across the country. Some of that spectrum is owned by Clearwire, others were acquired via long term leases.

Plain vanilla LTE and WiMAX are often called “4G”, but they are not “official” 4G standards, according to a strict definition by the ITU.

Summary of IMT-Advanced

Characteristics Technology
Deployment 2012-2015
Core networks IP based
Band Below 6GHz
Data rates 100 Mbps to 1 GHz
Access methods OFDMA, SC- FDMA, OFDM-TDMA
Radio Interface Cognitive radios, software defined radios.
Modulation QPSK, 16QAM, 64QAM, DAPSK
Services provided Rich multimedia, voice, high speed data.
Duplex methods FDD(paired, unpaired), TDD
Error control LDPC, turbo codes, HARQ
Handover Seamless, vertical, horizontal, hard, soft

The ITU requires 100 Mbps (mobile) and 1 Gbps (fixed) speeds, among other criteria, to qualify as true “4G”. That’s about 3 times the speed of today’s LTE and WiMAX systems.

A competing ITU 4G standard – WirelessMAN-Advanced, also known as ‘WiMAX 2‘ (IEEE 802.16m), was also approved by ITU in the IMT Advanced family.

Clearwire has chosen sides. They’ve chosen LTE over WiMAX. The new technology will complement Clearwire’s existing “Wimax” wireless technology, which forms the basis for the 4G service offered by Sprint-Nextel.

“This is the future of mobile broadband,” said Dr. John Saw, Clearwire’s Chief Technology Officer. “Our extensive trial has clearly shown that our ‘LTE Advanced-ready’ network design, which leverages our deep spectrum with wide channels, can achieve far greater speeds and capacity than any other network that exists today. Clearwire is the only carrier with the unencumbered spectrum portfolio required to achieve this level of speed and capacity in the United States.”

“In addition, the 2.5 GHz spectrum band in which we operate is widely allocated worldwide for 4G deployments, enabling a potentially robust, cost effective and global ecosystem that could serve billions of devices,” Saw added. “We anticipate that the economies of scale derived from this global ecosystem will act as a catalyst for the development of thousands of low-cost devices and applications. And, since we currently support millions of customers in the 2.5 GHz band, we know that our LTE network won’t present harmful interference issues with GPS or other sensitive spectrum bands.”

Clearwire also noted that since launching its first 4G market in 2009, video has become the largest component of the company’s overall data traffic and video traffic itself has increased more than tenfold since 2009. The company (Form S-1) believes that as more video-intensive smartphones and services rise, so will the needs for Clearwire’s high-capacity 4G wholesale network.

LTE Advanced is the next big thing, according to Qualcomm. It’s encompassed in 3GPP Rel. 10, 11 and beyond.

Sequans’ recently announced their 4Sight program, to help mobile operators transition smoothly and cost-effectively from WiMAX to LTE and enable harmonious WiMAX/LTE coexistence.

Clearwire-USA is one of the 20 members of the Global TD-LTE Initiative. Others include Aero2-Poland, Belltell-Philippines, Bharti Airtel-India, China Mobile-China, Datame-Finland, E-Plus – Germany, FarEastone-Taiwan, FITEL-Taiwan, Korea Telecom-Korea, Omantel-Oman, Nextwave-USA, P1-Malaysia, Smoltelecom-Russia, SoftBank-Japan, Tatung Infocomm-Taiwan, Vividwireless-Australia, Vodafone-UK, Voentelecom-Russia and Woosh-New Zealand.

Most WiMAX operators will migrate to LTE, but the pace and modalities of the shift will vary greatly depending on geography, service focus, spectrum availability, and funding, says Monica Paolini (PDF).

Packet One, a wireless ISP, expects to begin a transition to a full LTE network in 2013. Packet One, a subsidiary of Greenpacket, and a leading developer of 4G systems, is testing a dual-mode 4G WiMAX/LTE solution from Sequans for dual-mode WiMAX/LTE, and hopes to launch a complete ecosystem of 4G networking solutions and devices by the end of 2011.

Gemtek’s new TD-LTE indoor CPE is based on Sequans’ SQN3000 series LTE chips, which support up to 100 Mbps throughput and 20 MHz channels. “We expect the new CPE to begin commercial deployment in the third quarter of 2011,” said James Ting, GM, Broadband Wireless Business Unit, Gemtek.

“As Southeast Asia’s leading 4G operator, first for WiMAX and now for dual-mode WiMAX and LTE, P1 has three years of experience operating an end-to-end 4G network,” said Michael Lai, P1 CEO. Packet One uses 30MHZ of its 2.3GHz spectrum for WIMAX, but plans to re-farm 20MHz of this for LTE leaving 10MHz for its legacy WIMAX subscribers. This will happen in a gradual process over the next two years, Lai says.

Greenpacket is testing Sequans’ system-on-chip technology to develop LTE reference designs, including a dual-mode WiMAX/LTE reference design for operator customers primarily in Asia, CALA and Middle East.

Any Sprint Apple iPhone would likely have dual CDMA/WiMAX radios, like their other 4G smartphones that use Sequans chips. Sequans dual-mode chips can transition from WiMAX to LTE. Broadcom acquired Beceem which develops dual-band, LTE and WiMAX chips. Qualcomm’s next-generation Snapdragon supports LTE and both GSM and CDMA networks. Verizon uses it in their iPhone model. Skycross has a compact, tunable MIMO handset antenna that covers 12 frequency bands ranging from 700 MHz to 2.7 GHz.

It may be wishful thinking to expect unlimited (uncapped) broadband with Wi-Fi hotspot connectivity on Android and IOS devices. But it’s not an impossible dream.

Related Dailywireless articles include; Will Sprint Go TD-LTE?, WiMAX to TD-LTE: Everybody’s Doin’ It, Speculation on Sprint Infrastructure, LG Telecom: CDMA & LTE Handover, LTE Spectrum: It’s War, German 4G Auction: It’s Done, Auctions Winding Down in Germany & India, Germany 4G Auctions Begin, Europe to Follow, EU: Global LTE Roaming at 1.8 GHz, T-Mobile Makes Its (4G) Move, End Near for Indian WiMAX?, WiMAX & LTE: Policy Vs Pragmatism, Intel: LTE Not Nail in Coffin, India’s Broadband Auction: It’s Done, India’s Broadband Auction: No Free Lunch, TD-LTE Gains Momentum, WiMAX Forum: Not Dead Yet, Yota Dumps WiMAX, UK Getting LTE, WiMAX to TD-LTE: Everybody’s Doin’ It, Speculation on Sprint Infrastructure, LG Telecom: CDMA & LTE Handover, Australia: WiMAX to TD-LTE, WiMAX to TD-LTE: Everybody’s Doin’ It, Speculation on Sprint Infrastructure, LG Telecom: CDMA & LTE Handover, Australia: WiMAX to TD-LTE, LTE-Advanced Progress, Ericsson Demos 1 Gbps Advanced LTE , Sprint’s LTE Advantage, LTE-Advanced Tested in Korea, ITU: The “Official” 4G Standard Approved, WiMAX at 330 Mbps, Towards a REAL “4G” Standard, Unified “4G” Standard Proposed, WiMAX 2 Collaboration Initiative, IEEE Submits 802.16m to ITU for 4G, LTE-Advanced Submitted to ITU, MIMO: The Paper War, CTIA 2010, LTE-TDD & WiMAX: Two Peas in a Pod?, Blowback on 2.6 GHz, Towards a REAL “4G” Standard, and Unified “4G” Standard Proposed

Posted by Sam Churchill on Wednesday, August 3rd, 2011 at 1:00 pm .

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