Antenna Maker ArrayComm Pursues Wireless ISP Plans
By FRED DAWSON October 11, 1999
multichannel.com
Antenna-technology developer ArrayComm Inc. is working with unnamed partners to develop a nationwide high-speed-data-access system.
The move signals that previous assumptions about the transport capacity of fixed wireless networks will soon be overturned.
Starting late next year, ArrayComm expects large-scale field trials of its "i-BURST" system to begin in preparation for the launch of a 1-megabit-per-second Internet-access service in 100 cities representing 60 percent of the U.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 of the system -- slated for sometime in early 2002 -- would put ArrayComm and its carrier and vendor partners in position to capture a large share of the anticipated mass market for high-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 $2 billion. Officials said there's a second phase to the plan that will raise the data rate to about 2 mbps.
ArrayComm's move -- rooted in its proprietary spatial-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 to deliver high-speed services over relatively limited amounts of spectrum.
If they use small segments available below the 2-gigahertz level 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 and offices, because the lower frequencies have superior propagation characteristics.
ArrayComm needs the Federal Communications Commission to license a sliver of spectrum on the order of 5 megahertz to 10 MHz wide, Cooper said. The company's technology supports transmissions at a rate of 4 bits per hertz or frequency 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 connection that is sufficient to deliver 1 mbps in both directions, only in each instance where the communication is delivering a signal, thousands of users can be served over a tiny segment of spectrum from each base station transmitter/receiver.
"The technology allows you to talk to more than one person at a time on the RF channel in the same time slot," Cooper said.
That translates into spectral efficiency that is 400 times that of current-generation cellular and 40 times that of third-generation digital personal-communications systems that are slated to hit the market in 2002, Cooper added
"Remember," he said, "we're giving something up, which is the need to provide mobile service, so we can do things that these systems can't do."
Already supporting commercial services in Japan, Malaysia, the United Arab Emirates and, soon, China, ArrayComm has a head start over other antenna makers. But other suppliers are gearing up to provide systems that will make portable high-speed wireless-access services a reality within two years.
Engineers at Lucent Technologies' Bell Laboratories are testing cutting-edge antenna technologies in various deployment configurations in and around Crawford Hill, N.J., which offer systems integrators a variety of options for addressing wireless-capacity-expansion needs, said Rich Howard, director of Lucent's wireless lab.
"We've come a long way in figuring out how to integrate and apply our innovations in real-world networking situations," Howard said. Now, he added, it's a question of when market demand will drive systems integrators to begin making use of the technology.
"If you believe there's going to be a widespread market push for wireless data, wireless operators will have no choice but to use every trick in the book to improve bandwidth efficiency," Howard said. "What we're working on is the biggest trick of all."
Lucent's wireless lab group is confident that the advanced antenna techniques could be quickly put to use in network systems to effect 10-fold to 20-fold increases in capacity over a given wireless link and to overcome the interference problems that will intensify as the use of wireless spectrum for delivering services in competition with wireline networks accelerates.
These techniques include an innovation announced late last year, known as "BLAST." That approach uses multiple transmit and receive antennas to exploit the multipath nature of wireless communications, and a marriage of this technique with steerable antenna-beam technology in a multipurpose combination can address market conditions ranging from urban centers to the suburban fringes.
BLAST employs Lucent-developed algorithms to assign specific signals to specific transmission paths in the multipath dissemination of a radio wave at a given frequency, thereby allowing reuse of the frequency many times over for delivery of different messages to and from different users.
In contrast, the company's multibeam-antenna system serves multiple customers over the same frequency by moving a wide beam from customer to customer in quick, millisecond hops that are timed to coincide with the time slots assigned to each customer in a time-division multiplexing configuration.
BLAST is ideal for an urban environment, where densely packed building surfaces create the reflective patterns needed for multipath communications. The steerable-beam technology is good for increasing the information-carrying capacity in suburban areas.
By employing multiple-antenna arrays at the transmit and receive ends, Lucent has found that it can combine the two techniques to maximize the benefits of each, depending on where a base station is located, Howard said.
"The hardware is identical -- multiple antennas with multiple radios," he added. The key is to activate the hardware via algorithms that match the local situation.
Today, digital-signal processors are still too expensive to allow for multiple antennas at the receive end, Howard said. But within the next year or so, the cost curve could fall far enough to make commercial applications of the integrated advanced antenna system feasible.
Nobody is more interested in deriving higher data-carrying capacity from limited spectrum than AT&T Wireless. That unit's executives have spoken often about "Project Angel" as a wireless solution to delivering high-speed-data and voice services over cellular, PCS and other spectrum. |
