Interoperability to drive LTE acceptance

ZTE exec says platform's compatibility with FDD LTE spells economies of scale for all, as Chinese manufacturers celebrate TD-LTE's milestones.

SHANGHAI--As more operators move toward LTE, the telecoms industry can expect interoperability between TDD (time division duplex) and FDD (frequency division duplex) LTE flavors to bring about economies of scale for the entire mobile communications ecosystem, said Donglin Shen, wireless product CTO at ZTE.

Speaking at the NGMN (Next Generation Mobile Networks) industry summit here Wednesday, Shen noted that interoperability within LTE's technologies will mark a difference from the current segmentation between GSM and CDMA. The two telecoms technologies are incompatible, and their respective devices cannot work on the other's network.


LTE deployments are split between FDD (frequency division duplex) and TDD (time division duplex) technologies. Together with WiMax, all three can be operated by the same base-band unit, although the radio transmitter is shared by TDD and WiMax--itself a TD technology.

FDD-LTE networks use a different radio because they require paired spectrum, while TDD is able to run on narrower bands, explained Sudhakar Ramakrishna, corporate vice president of wireless broadband access and software operations for Motorola's home and networks mobility division.

He said TD-LTE is more suitable for operators with limited spectrum because it can operate within a narrower band as it does not require paired spectrum, unlike FDD-LTE.

This has brought about inefficiencies related to roaming issues for users, and siloed development efforts for each technology, he said. With the world to be "unified" under LTE eventually, he noted that the industry can expect much greater economies of scale for hardware makers and services providers.

Services players can look forward to "unified application scenarios" where they can roll out across different carriers, regardless of the technology chosen, Shen said.

Bill Huang, China general manager of China Mobile's mobile research institute, said TD-LTE development, although initiated two years later than FDD LTE, has caught up with the latter and reached commercial viability.

Showcasing a host of end-user CPE (customer premises equipment) and dongles, Huang said TD-LTE has reached a new milestone in market readiness.

Planning TD-LTE future
China Mobile has been one of TD-LTE's biggest backers. The Chinese operator had a part in its development as a successor technology to the country's homegrown 3G TD-SCDMA standard, which China Mobile also developed.

Huang said initial development efforts began in December 2007, culminating in the first proof of concept demonstrated in August last year. TD-LTE was submitted to the ITU (International Telecommunication Union) last December for ratification as a standard.

Shen said steps now need to be taken to push broader TD-LTE coverage. Its backers will also spend time reaching out to network operators that predominantly rely on voice revenues and help them build a business case for mobile data, he added.

Given its role in TD-LTE's development, China Mobile is one player that will benefit from the global embrace of the technology, said Sudhakar Ramakrishna, corporate vice president of wireless broadband access and software operations for Motorola's home and networks mobility division.

The operator's earlier TD-SCDMA standard was deployed only in China and as a result, its development was hampered by the lack of participation from global telecoms players, said Ramakrishna.

He added that the TD-LTE market is expected to be as sizable as that of FDD.

While most GSM-running operators in the Asia-Pacific region, Europe and North America will likely upgrade along the FDD path due to common technologies, TD-LTE will predominantly be found in China, India and Russia--three large bases that will even out the spread of the two technologies globally, he said.

He noted that some operators in India have earmarked TD-LTE as a way to hop on the 4G gameplay, in particular 2G carriers that did not participate in the recent 3G auction and want to skip 3G altogether.

Russia, on the other hand, has a lot of unpaired spectrum and TD-LTE is a more suitable technology path for the country, Ramakrishna said.

Victoria Ho of ZDNet Asia reported from the NGMN (Next-Generation Mobile Networks) Industry Conference 2010 in Shanghai, China.


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