Antenna Maker ArrayComm Pursues Wireless ISP Plans
Antenna-technology developer ArrayComm Inc. is working withunnamed partners to develop a nationwide high-speed-data-access system.
The move signals that previous assumptions about thetransport capacity of fixed wireless networks will soon be overturned.
Starting late next year, ArrayComm expects large-scalefield trials of its "i-BURST" system to begin in preparation for the launch of a1-megabit-per-second Internet-access service in 100 cities representing 60 percent of theU.S. population, chairman and CEO Martin Cooper said.
"For this system to be real, it has to be ubiquitous,and we think this is the scale we have to start at," he added.
Cooper said the anticipated timing of commercial rollout ofthe system -- slated for sometime in early 2002 -- would put ArrayComm and its carrier andvendor partners in position to capture a large share of the anticipated mass market forhigh-speed wireless services.
"We're not competing with wireline services,because our system is designed to give users access wherever they are," he added.
ArrayComm expects the cost of deployment to be under $2billion. Officials said there's a second phase to the plan that will raise the datarate to about 2 mbps.
ArrayComm's move -- rooted in its proprietaryspatial-division multiple-access antenna technology -- comes as a number of entities,including AT&T Corp., are tapping smart-antenna and other techniques to enable them todeliver high-speed services over relatively limited amounts of spectrum.
If they use small segments available below the 2-gigahertzlevel that are not already used for mobile voice, broadcast TV and other applications,they can reach users with saturation coverage, both inside and outside of their homes andoffices, because the lower frequencies have superior propagation characteristics.
ArrayComm needs the Federal Communications Commission tolicense a sliver of spectrum on the order of 5 megahertz to 10 MHz wide, Cooper said. Thecompany's technology supports transmissions at a rate of 4 bits per hertz orfrequency cycle, which translates into 40 mbps if 10 MHz of spectrum is used, he added.
By focusing a portion of the RF energy on each connectionthat is sufficient to deliver 1 mbps in both directions, only in each instance where thecommunication is delivering a signal, thousands of users can be served over a tiny segmentof spectrum from each base station transmitter/receiver.
"The technology allows you to talk to more than oneperson at a time on the RF channel in the same time slot," Cooper said.
That translates into spectral efficiency that is 400 timesthat of current-generation cellular and 40 times that of third-generation digitalpersonal-communications systems that are slated to hit the market in 2002, Cooper added
"Remember," he said, "we're givingsomething up, which is the need to provide mobile service, so we can do things that thesesystems can't do."
Already supporting commercial services in Japan, Malaysia,the United Arab Emirates and, soon, China, ArrayComm has a head start over other antennamakers. But other suppliers are gearing up to provide systems that will make portablehigh-speed wireless-access services a reality within two years.
Engineers at Lucent Technologies' Bell Laboratoriesare testing cutting-edge antenna technologies in various deployment configurations in andaround Crawford Hill, N.J., which offer systems integrators a variety of options foraddressing wireless-capacity-expansion needs, said Rich Howard, director of Lucent'swireless lab.
"We've come a long way in figuring out how tointegrate and apply our innovations in real-world networking situations," Howardsaid. Now, he added, it's a question of when market demand will drive systemsintegrators to begin making use of the technology.
"If you believe there's going to be a widespreadmarket push for wireless data, wireless operators will have no choice but to use everytrick in the book to improve bandwidth efficiency," Howard said. "Whatwe're working on is the biggest trick of all."
Lucent's wireless lab group is confident that theadvanced antenna techniques could be quickly put to use in network systems to effect10-fold to 20-fold increases in capacity over a given wireless link and to overcome theinterference problems that will intensify as the use of wireless spectrum for deliveringservices in competition with wireline networks accelerates.
These techniques include an innovation announced late lastyear, known as "BLAST." That approach uses multiple transmit and receiveantennas to exploit the multipath nature of wireless communications, and a marriage ofthis technique with steerable antenna-beam technology in a multipurpose combination canaddress market conditions ranging from urban centers to the suburban fringes.
BLAST employs Lucent-developed algorithms to assignspecific signals to specific transmission paths in the multipath dissemination of a radiowave at a given frequency, thereby allowing reuse of the frequency many times over fordelivery of different messages to and from different users.
In contrast, the company's multibeam-antenna systemserves multiple customers over the same frequency by moving a wide beam from customer tocustomer in quick, millisecond hops that are timed to coincide with the time slotsassigned to each customer in a time-division multiplexing configuration.
BLAST is ideal for an urban environment, where denselypacked building surfaces create the reflective patterns needed for multipathcommunications. The steerable-beam technology is good for increasing theinformation-carrying capacity in suburban areas.
By employing multiple-antenna arrays at the transmit andreceive ends, Lucent has found that it can combine the two techniques to maximize thebenefits of each, depending on where a base station is located, Howard said.
"The hardware is identical -- multiple antennas withmultiple radios," he added. The key is to activate the hardware via algorithms thatmatch the local situation.
Today, digital-signal processors are still too expensive toallow for multiple antennas at the receive end, Howard said. But within the next year orso, the cost curve could fall far enough to make commercial applications of the integratedadvanced antenna system feasible.
Nobody is more interested in deriving higher data-carryingcapacity from limited spectrum than AT&T Wireless. That unit's executives havespoken often about "Project Angel" as a wireless solution to deliveringhigh-speed-data and voice services over cellular, PCS and other spectrum.
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