September 17, 2003 10:10 p.m. EDT

TELECOMMUNICATIONS

Cellphone 'Dead Zones' May Be Thing of the Past By CHRISTINE NUZUM DOW JONES NEWSWIRES NEW YORK -- Modern cellphones that send snapshots and serve up video games are quickly replacing traditional long-distance phone service. But eliminating dropped calls is still a challenge because of the irksome disruptions of so-called dead zones. Dead zones result from fading or degradation of the wireless signal that occurs when electromagnetic waves bounce off objects or collide and interfere with one another. Such degradation also cuts short wireless data transmissions, and slows or cuts off wireless Internet access. A few companies, including Qualcomm Inc. and a little start-up called Magnolia Broadband, want to change this by embedding extra antennas inside handsets. Known as "antenna diversity," it's a technology that has been around in a more rudimentary form since the early days of wireless -- but in the network rather than the handsets. Antenna diversity in handsets would increase the capacity of a network, while improving the likelihood the signal from one antenna will get through even when the other signal meets interference. In addition to improving the performance of wireless services, it could allow a carrier to cover more subscribers. With wireless data files becoming much larger due to photos, games and, eventually videos, carriers are looking for more ways to make the most of the spectrum they have. Along with phone manufacturers, they are now considering putting more antennas in handsets. In recent years, research at various institutions, including Virginia Polytechnic Institute and State University in Blacksburg, has demonstrated that installing multiple antennas in mobile devices has extra benefits for wireless performance, even when antenna diversity is already in place in the network. The benefits are particularly clear for data-intensive applications. "Wi-Fi," or high-speed wireless networking devices, such as PCs that have wireless-Internet access, already carry antenna diversity. Traditionally, antenna diversity involves switching between antennas, depending on which is receiving the strongest signal. These are the sorts of systems that have long been in wireless networks and are being installed in Wi-Fi devices. "You can do even better if you don't just choose the signals but you combine them together through signal processing," said James Hicks, a research faculty member at Virginia Tech. More sophisticated antenna-diversity systems involve processing signals from both antennas simultaneously and combining them. "It's equivalent to allowing you to cup your ears so you can hear from a particular direction better," said Jeff Reed, a professor of electrical engineering at Virginia Tech. These haven't been widely installed in devices so far, but some companies are in the late stages of integrating them into mobile handsets, among them Qualcomm. Carriers in the U.S. and abroad are testing Qualcomm's prototype antenna-diversity handsets and the company expects them to hit the market next year. "We have a lot of interest from CDMA carriers because they see this as a very feasible and cost-effective technique to improve the performance of their phones and of their networks," said Qualcomm Chief Technology Officer Roberto Padovani. Qualcomm claims antenna diversity in the handset is only practical for carriers that use the CDMA standard: Verizon Wireless, owned by Verizon Communications and Vodafone PLC; and Sprint PCS Group in the U.S. Carriers using the GSM standard, such as AT&T Wireless Services Inc., Deutsche Telekom AG's T-Mobile, and Cingular Wireless, owned by SBC Communications Inc. and BellSouth Corp., would have to switch all their customers to the technology for it to have any benefit, Dr. Padovani said. Qualcomm has long been a vocal proponent of the CDMA standard. By the end of 2004 or early in 2005, Dr. Padovani expects that Qualcomm's antenna-diversity system won't add more than $2 or $3 to the cost of manufacturing handsets, although they may be initially more expensive. Coverage will improve as more subscribers get the new handsets, said Dr. Padovani. When half of a carrier's subscribers have the handsets, its spectrum will be able to accommodate 50% more subscribers; when all or nearly all are upgraded, the network coverage will double. Qualcomm sees data-speed improvements of more than twofold. Qualcomm expects adoption to be gradual and that it will be many years before the technology is universally adopted by a carrier's customer base in order to double its coverage. Dr. Padovani thinks that carriers would initially target certain groups of consumers, although he emphasizes that carriers haven't informed him of their plans for distributing the technology. Carriers might first roll out the phones to those with the most expensive plans or those in areas where the spectrum is too crowded, or both, he said. Targeting high-end consumers would reward those who spend the most. Because these also tend to be the subscribers that send the most weighty files -- such as photos and data -- it would ease some of the greater strains on the network. One further step in technological evolution involves transmitting as well as receiving signals from multiple antennas. By using two antennas tuned at different frequencies in transmission, the electromagnetic waves that form the cellular signal can combine to form a narrower beam less subject to interference. A feedback system from the network tells the device which antenna is emitting the stronger signal. "This is one of the hottest areas that I've seen right now," said Dr. Reed of Virginia Tech. "There're lots of companies that are looking at this." One of the first to deploy it may be Magnolia, a three-year-old New Jersey company with $15 million in funding. Magnolia expects to be able to offer carriers prototype handsets to test at the end of this year or early in 2004. Magnolia anticipates that its upgraded handsets will be available to consumers in the second half of 2004. Magnolia says its system has the same correlation between portion of subscribers covered and network-capacity improvements as Qualcomm's. But antenna diversity on the transmission end has additional benefits, according to Magnolia Chief Executive Haim Harel. It extends a handset's battery life to allow 15% more talking time, or an extra hour, before recharging is required. It also significantly cuts the risk possibly presented from cellphone emissions, said Mr. Harel, acknowledging that whether such emissions are harmful is still being debated. One of the roadblocks to transmitting wireless signals from more than one antenna has been spacing. The antennas need to have a certain minimum distance between them, and as handsets get smaller, fitting the adequately spaced antennas onto a handset has proved problematic. But Magnolia says it has a proprietary algorithm that resolves that issue. Qualcomm is still working on antenna diversity for transmission from the handset. "That will take definitely more work and longer time," said Dr. Padovani, who estimates it will take another four or five years for the company's handset-transmit diversity to be complete. Many people think the technology won't be in high demand before then. "We believe that most consumers won't generate high data rates, but they will receive high data rates," said Carl Panasik, director of advance architecture in wireless research and development at Texas Instruments Inc. Indeed, Texas Instruments sees this as a technology that can wait for three or four years until cellphones are regularly used to transmit real-time video. "We're envisioning people watching movies on their handsets; we're envisioning people using them as video phones," said Mr. Panasik. "Video unfortunately reveals all the flaws in wireless communications and we'd like to circumvent them if we can today. If I set up a video link and I move my lips, I think you'd like to see that my lips move with the voice and that everything lines up. We don't want this to look like a bad science-fiction movie." But Mr. Panasik doesn't see this as an issue for consumers in the next year, and expects it will be another three or four years before Texas Instruments deploys antenna diversity in the handset. "At the data rates that we move voice, we don't really see this to be a benefit," said Mr. Panasik. Write to Christine Nuzum at christine.nuzum@dowjones.com^1 URL for this article: http://online.wsj.com/article/0,,SB106383361553747700,00.html Hyperlinks in this Article: (1) mailto:christine.nuzum@dowjones.com Updated September 17, 2003 10:10 p.m.

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