|
Current Issue: March 2008
Cover Story
LTE has WiMAX in its sights
The battle for "4G" intensifies as LTE supporters claim growing momentum
by Ken Wieland
LTE is the hottest buzz-acronym in the mobile industry. Those attending the Mobile World Congress (MWC) extravaganza in Barcelona last month were bombarded by messages from a variety of vendors (and some operators) saying the time for LTE, or long-term evolution, is drawing ever closer.
And with momentum apparently gathering for this all-IP mobile broadband technology (dubbed "4G" in some quarters), one possible interpretation is that time is running short for mobile WiMAX (which purports to occupy the 4G space now) to establish itself as a mainstream mobile broadband technology.
Alcatel-Lucent and NEC were among the loudest LTE drum bangers at MWC. The two companies announced in Barcelona they had created a 50/50 joint venture exclusively focused on LTE development. The companies will combine existing R&D resources on LTE with the aim of each releasing its first single LTE product line before the end of 2009.
"There are two triggers for the JV with NEC," says Alcatel-Lucent CTO Olivier Baujard. "Increased scale in R&D and market reach, and getting commercial products quicker to market on a global basis."
NEC is already trialing LTE with NTT DoCoMo, while Alcatel-Lucent is trialing LTE with Verizon. "Customers have reacted very positively [to the JV]," Baujard says. "They can see it will be backed by around twice as large R&D and system architecture capability."
The prospect of supplying NTT DoCoMo is a key attraction for Alcatel-Lucent, which Baujard believes will be the earliest and biggest adopter of LTE worldwide. But NEC benefits, too, with the chance of getting a firmer toehold in Western markets.
The LTE product line will develop both FDD (frequency division duplex) and TDD (time division duplex) variants aimed at both CDMA and WCDMA operators. Baujard is optimistic the JV will mushroom quickly. "I wouldn’t be surprised if the JV with NEC, after two or three years, had about 1,000 staff," he says.
Ericsson also demonstrated at MWC what it claimed to be the world’s first end-to-end phone call enabled by LTE. The Swedish supplier says its LTE network equipment supports multi-user data rates of up to 160Mbps per cell, using handheld mobile devices developed by Ericsson Mobile Platforms.
Not so long ago, the general industry consensus was that LTE wouldn’t be around until after 2010. But now, major suppliers are saying the first commercial deployments will be much sooner. Robert Puskaric, head of Ericsson’s mobile platforms business, in a prepared statement released during MWC, said, "This world-first demonstration marks a key milestone in the development of LTE. It proves the stability and integration of our platform with a form-factor-accurate handheld device, reaching uplink and downlink data speeds of 25Mbps already today. Samples of our first LTE platform will be available in 2008."
Jean-Pierre Bienamé, chairman of the UMTS Forum (which supports the 3GPP "family of standards", which it says includes LTE), is equally bullish on LTE development. "I think 90 to 95 percent of LTE standardization is already finished," he says. "I am confident we can finalize the LTE standard by the middle of this year, have the first commercial deployments by 2010, and have widespread deployments during 2011."
In January 2008, 3GPP announced some of the RAN (radio access network) specifications had been frozen, but it was generally believed at the time it wouldn’t be until the end of the year that the 3GPP Release 8 specification for LTE would be finalized.
Bienamé clearly sees it differently and insists there has been no undue haste to catch up with mobile WiMAX in the wake of comments made by Arun Sarin at last year’s show in Barcelona. At the 3GSM event, the Vodafone CEO famously threw down the gauntlet to 3G suppliers to develop data-friendly networks as quickly as possible. He noted that other data-centric technologies, such as WiMAX, could "eat our lunch."
Chris Beardsmore, WiMAX product marketing manager at Intel, which has invested more than US$1bn in WiMAX operations around the world, is skeptical that LTE suppliers will deliver commercial networks in such a short timeframe. "The LTE standard has yet to be finalized and there is still a lot of work to done," he says. "We were doing the same booth demos as LTE are doing now more than two years ago on mobile WiMAX, and we didn’t have a standard agreed [upon] until December 2005."
Bienamé remains undaunted and adds that the NGMN (next generation mobile network) initiative, created last year by some of the world’s leading mobile operators to look at 4G options, is destined to go for LTE. "I think if you take an open view, without being partisan, there is a major trend for converging toward LTE," he says.
Recent announcements would seem to support Bienamé’s view. Telstra, AT&T and Verizon already have committed to LTE and, during the course of the MWC event, China Mobile also revealed it would join Verizon Wireless and Vodafone in coordinating LTE trials, which will focus on both FDD and TDD modes. The TDD emphasis is significant given that China’s homegrown 3G standard, TD-SCDMA, uses TDD. A TDD variant would give LTE a better chance of adoption in China as a 4G path from TD-SCDMA.
As the bulk of mobile WiMAX R&D has gone on TDD, it hardly can be ruled out as a 4G contender in the China market. But the announcement by Ericsson earlier this year that it had demonstrated LTE in both FDD and TDD modes on the same platform would seem to suggest the Swedish supplier, which has no mobile WiMAX portfolio of its own, is looking to compete directly with mobile WiMAX on TDD territory.
The WiMAX Forum is believed to be exploring FDD solutions of its own, however, which would enable it to compete head to head with LTE in the 4G space where operators have suitable spectrum allocations that would allow them to go down either the LTE or WiMAX route.
A converged 4G standard?
Vodafone’s Sarin, speaking at this year’s MWC, called for "unified standards." His proposal is to integrate TDD WiMAX with FDD LTE into a single standard, which would, theoretically, make the lives of carriers much easier. No longer would they have to test both WiMAX and LTE equipment separately and, again theoretically, it would eventually reduce infrastructure costs and optimize R&D resources already allocated by LTE and WiMAX suppliers on FDD and TDD respectively.
Technically, there appears to be no insurmountable barrier to making a unified standard happen. "We estimate there is around 75 to 80 percent reuse between WiMAX technology and LTE," says Fred Wright, Motorola senior vice president of WiMAX and cellular networks. "The LTE equipment we have basically uses WiMAX hardware components, although the software is different."
Wright is not prepared to speculate how long it would take to make WiMAX and LTE interoperate in one single standard. Alcatel-Lucent’s Baujard believes, however, it could take up to "several years."
"If standards do converge, I think it would be best for everyone involved," Wright adds, but IPR issues could be a problem. The WiMAX community has managed to establish a distributed IPR regime where no one company dominates. "We [Motorola] are proposing a similar IPR structure [to various standards groups] for LTE because it is good for the industry," Wright says. "If we have rational people out there, we can work it out."
Motorola, like Nokia Siemens Networks, Alcatel-Lucent, Samsung and Nortel, is developing LTE at the same time it is shipping WiMAX equipment. And with a view on the two technologies, Wright distances himself from comments made by the likes of the UMTS Forum that LTE is more compatible with 3G than WiMAX (see Is LTE a more optimal 4G path than WiMAX?, top right).
"LTE is going to be, essentially, an overlay network," he says. "It doesn’t matter who the incumbent supplier is. The vast majority of base stations that exist today in the world of UMTS or GSM are not upgradeable. Let’s say an Ericsson or a Nokia does have a brand new base station that is upgradeable to LTE. What percentage of those base stations will exist in the global market by the time you start rolling out LTE anyway?"
At the moment, Wright says there is almost no hardware reuse between UMTS and LTE. However, Motorola has developed a retrofit kit to allow an LTE carrier to be installed in Verizon’s existing GSM base stations. By using the same physical package, this will help conserve floor space and optimize power consumption.
But, as Wright is keen to point out in all the debate surrounding LTE and WiMAX, WiMAX has one main advantage over its would-be 4G rival. "The one thing LTE doesn’t have going for it is it doesn’t exist. WiMAX is here and now," he says.
Wright says Motorola has shipped more than 3,000 WiMAX base stations and shipped almost 50,000 CPE units. With 16 contracts with operators, another 60 "active engagements," and a WiMAX order book worth nearly US$1.5bn, Motorola’s WiMAX business is growing impressively. "WiMAX fills a very defined need for certain operators around the world," he says.
|
