Motorola sees TD-LTE in WiMax future

SHANGHAI--TD-LTE is a good migration option for WiMax operators, provided they have sufficient spectrum, according to Motorola executives.

Bruce Brda, Motorola's senior vice president and general manager of home and networks mobility, said in an interview with ZDNet Asia here Wednesday at the NGMN (Next-Generation Mobile Networks) Industry Conference, that TD-LTE presents a path for existing WiMax operators competing with telcos that provide 3G mobile broadband.

While WiMax deployment is expected to grow quickly, Brda said this will likely reach its height in about three to four years' time. In the meantime, the LTE services and hardware ecosystem will grow to dwarf it and present a more attractive choice to both users and carriers, he added.

Carriers can choose to deploy LTE networks either in FDD (frequency division duplex) or TDD (time division duplex) versions. Since WiMax is a TD technology and shares more assets with the latter, TD-LTE presents a more efficient migration option for WiMax operators, Brda explained.

Spectrum needed for TD-LTE
However, he does not expect every WiMax operator to move to LTE.

Those with broad spectrum rights such as Clearwire in the United States have the option of dividing up that spectrum between WiMax and TD-LTE so that they can enter the LTE market without cutting off their existing subscriber base, he said.

But a small carrier with limited spectrum will not be able to maintain both business lines, and will have to decide between the two platforms, Brda said.

This does not mean that all WiMax carriers will eventually evolve into LTE operators, he qualified. Those with limited spectrum will also not have the bandwidth to scale up for a big LTE user base and are advised to keep to smaller, "focused" coverage areas.

He said this may run contrary to WiMax's reputation as a last-mile technology for rural areas, but he noted that there are success stories in developed and dense urban settings where smaller WiMax operators hone in on selected hot zones with the aim of "filling them up with users".

He said WiMax accounted for 14 percent of Motorola's networking business in the first quarter of this year. In comparison, CDMA made up 45 percent and GSM 30 percent.

Raising R&D efficiencies
Motorola is placing its bets on WiMax and TD-LTE to drive up shared R&D (research and development) assets for the company, said Brda.

He explained that base station units can be shared by WiMax, TD-LTE and FDD LTE but the next hardware layer, the radio transmitters, are shared by WiMax and TD-LTE because they are both single spectrum technologies. FDD LTE requires paired spectrum.

As a result, Motorola expects its investments in TD-LTE to be reused for WiMax equipment. It currently achieves 70 percent efficiency between its WiMax and LTE R&D efforts, and hopes this can be raised, Brda said.

The company spends about 16 percent of its budget on R&D.

He said the company's wireless business reported in the first quarter of this year earnings of US$125 million, out of total sales of US$896 million.

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