China's homegrown spec hits true 3G speed

After stalling out at the 2.5G arena for some time, China's third-generation mobile-phone technology recently broke into the realm of honest-to-goodness 3G, with handset data rates ratcheting up to 384Kbps in real-world conditions. Meanwhile, it looks likely that the government will choose the country's largest carrier, rather than a second-tier one, to launch the technology. That's welcome news to the small group of chip companies that have bet their future on TD-SCDMA.

"The logic is that China Mobile is the strongest carrier, so if anybody can make TD-SCDMA successful, then they are the most likely to pull it off," said Ted Dean, a principal analyst at telecom consultancy BDA China. "But things will eventually depend upon how well the technology performs and how committed handset vendors are to bringing interesting products to market."

By most accounts, the move to TD-SCDMA has been a slog. But with the government's dogged backing, progress is being made. Last November, Analog Devices Inc. (ADI) said trial networks had been able to hit speeds of up to 384Kbps. In 2005, only 64Kbps links were possible; by mid-2006, the network was stable up to 128Kbps but still short of the target. Achieving data rates on par with 3G specs is a big boost.

"It is a little early to say that in every nook and cranny in every city, we can guarantee 384Kbps," said Doug Grant, director of business development for RF and wireless systems at ADI. "But .. this is not just ideal conditions in a laboratory environment. This is real-world stuff on a live network."

More upgrades needed
While the latest milestone is good news for TD-SCDMA backers, the technology still lags behind the more mature W-CDMA and cdma2000 1X, which will also be licensed in China. Both technologies have been upgraded since their release to hit downlink data speeds of at least 2Mbps. TD-SCDMA chip designers are working on similar upgrades, which are expected in the latter part of 2007.

China has more than 400 million mobile users, with millions more signing up every month. Spending on its 3G market will easily run into the tens of billions of dollars over the next few years as networks are fully built out. But China has held back on issuing licenses because of the immaturity of its local standard, leaving confounded chip- and gear makers to await the spending spree's start.

After five years of guessing when 3G licenses will be issued, now industry pundits will be free to predict which operators will use what technology, and how successful they will be. There will also be some debates on whether 3G will really be more about voice in China than it is about value-added services like data and video.

Chipmakers must pay close attention to both discussions. If China Mobile does pick up TD-SCDMA, it will probably target higher-end users with sophisticated phones and shift them off its huge GSM network, of more than 200 million users. If a fixed-line carrier has to start a green-field operation, however, then low-end phones that are voice-centric but with some multimedia would be favored in the initial rollout, to rapidly pick up users.

Insufficient chipsets
At the moment, China Mobile is overseeing test networks operating in Qingdao, in Shandong Province; Baoding, in Hebei Province; and Xiamen, in Fujian Province. The government said in November that 20,000 users would be given TD-SCDMA phones to test in those cities as well as in Beijing and Shanghai. Just before the tests began, however, 5,000 phones slated to go to Beijing were reportedly cut to 200 because of a shortage. The cause of the drastic cutback was traced back to insufficient chipsets in production.

Despite the increase in data rate links, some insiders say, voice connection reliability ranges from 80 percent to just over 95 percent, depending on the handset. The government target is 95 percent. Still, even in a worst-case scenario, in which only one or two chipset providers are tapped in the beginning, supplies should be sufficient. "The volumes being discussed for 2007 are not huge," said Grant, who put the likely supply at a few million handsets.

New players are also coming into the market, adding to the half-dozen already present. Last Octobeer, Shanghai-based Comlent Inc. released a TD-SCDMA transceiver. More recently, another Shanghai firm, RDA Microelectronics, said it was sampling a TD-SCDMA transceiver and seeing a sharp rise in orders for its power amps for TD-SCDMA base stations.

While a once incredibly reluctant China Mobile is not exactly in love with TD-SCDMA, the company is warming to it, believes Vincent Tai, chief executive of RDA. "After all this testing, I think they generally feel more comfortable."

- Richard Goering
EE Times