While the personal communications services industry in general remains locked in a three-way split over an airlink standard for systems deployment, cable TV operators in the PCS business so far have pitched their tents in the Code Division Multiple Access camp.

CDMA got a large boost this summer when the Sprint Telecommunications Venture shocked some in the industry by opting for spread-spectrum technology over Global System for Mobile communications. But although it’s a strong endorsement, it doesn’t necessarily represent a standard for the cable world. Even Sprint hasn’t entirely ruled out GSM.

Of the major trading area licensees now implementing their game plans, STV, comprising Sprint, Comcast Corp., Cox Enterprises and Tele-Communications Inc.; as well as fellow licensee Centennial Cellular Corp., a division of cable operator Century Communications Corp., have pledged their allegiance to CDMA.

However, the allegiance to CDMA does not necessarily extend far beyond STV within the cable industry, according to Mark Lowenstein, director of wireless research at The Yankee Group. STV’s reasons for choosing CDMA were related more to financing and capital than technology, he said.

Yet technology is an issue for those cable operators planning to actually transmit PCS over their existing infrastructure and not build entirely new networks-a group that eventually will include STV partners.

Cable operators that chose CDMA had in mind both long-term success at interconnecting their systems with digital cellular carriers as well as with integrating the standard with their own cable technology. STV cable operators selected CDMA because tests at Cox in southern California determined it works better than GSM with existing cable plant.

For cable operators, PCS is an opportunity to leverage their existing outside plant equipment and develop a new source of revenue. It’s a way for the cable industry to penetrate the $100 billion local telephone market and gain more loyalty from their existing cable subscribers without gaining all the regulatory restrictions that go along with being a wireline operator.

Perhaps the largest role cable players will contribute to PCS development is as a transport provider. STV plans to use its cable partners’ networks heavily for interconnecting cell sites back to the wireless switches. Wherever it can, STV will use a special technology to carry PCS over its existing cable networks and reduce the need for traditional cellular towers requiring exhaustive zoning approvals.

“As pioneered by Cox out of San Diego, we expect to use [cable operators’] plant to deploy an antenna technology called RAD/RASP [remote antenna device/remote antenna signal processor],” said Tom Mateer, vice president of strategic development for STV. “Basically, we’re going to [use] antennas instead of large towers. We can actually string antennas along the aerial plant on the cable system and receive the signal to transmit and bring that back to the headend [and] ultimately to the STV switch.”

A remote antenna driver will convert a PCS signal of between 1.8 GHz and 2.2 GHz to a lower frequency of 5 MHz to 40 MHz, allowing the signal to travel upstream on the cable network to the headend. In the other direction, the device can receive a signal traveling downstream and compress it into a higher frequency for wireless transmission.

Cox originally had selected GSM as its standard of choice, but withdrew this summer from its contract with Ericsson Inc. for GSM equipment.

“It’s not that GSM would not work,” said Bruce Crair, vice president and general manager for Cox California PCS. “It’s just that CDMA is a better technology for our application.”

Cox engineers found it was easier to transmit CDMA’s steady stream of information over the cable plant rather than transmitting a GSM signal broken up in time slots for which they’d have to deal with keeping that sensitive timing configuration, said Mateer. CDMA is just a “cleaner” technology for RAD/RASP, he explained.

In addition, a tower for a cell site costs $150,000 to $5 million to build and 12 months to 24 months to put in place-with most of the time involved with getting zoning approvals, said Crair. Installing a remote driver takes an hour and doesn’t require any zoning approvals, he said. Plus, it can be easily moved to accommodate changes in PCS system capacity needs for different areas.

“It gives us a certain advantage,” said Mateer. “To the extent that we are in a position to use the cable infrastructure, then we don’t have that zoning issue to contend with. We also expect that since we’re not constructing relatively expensive towers and transmission equipment that it will be a less expensive alternative for us to use as well.”

Cox, which likely will be the first cable operator to launch PCS service, plans to employ remote drivers-in lieu of traditional cell sites-as extensively as possible for its initial launch of PCS over cable TV networks in southern California; it was this technology concept that served as the basis for its winning a pioneer’s preference in the first place. STV plans eventually to incorporate the technology as well in its PCS networks nationwide.

“We want to use it at the earliest possible point,” reported Mateer. “We would hope to use it when we first go to market. But it is probably more likely, since this is a pioneering technology, it won’t be available immediately upon our buildout of all markets. Certainly as that technology develops we plan to deploy it more and more in the system.”

Although Sprint’s allegiance to CDMA-important for the RAD/RASP technology-seems strong, it comes with some strings attached. Company officials have indicated the decision announced this summer to use CDMA is contingent upon whether CDMA vendors actually can deliver equipment in time-a common ultimatum these days. STV is still negotiating with vendors and has not made any vendor-specific announcements nor laid any money on the table for the technology.

Lowenstein said AT&T Network Systems Inc. and Northern Telecom Ltd. are high in the running for the STV infrastructure contracts. A decision is expected by the end of the year.

“We have a firm commitment to CDMA, but…if the vendors are not able to come up with an acceptable price and financing and if there’s a question about their ability to deliver product as promised, we have not said unilaterally we will not go GSM,” said Mateer.

“Right now we have every expectation that the vendors will be able to meet the commitment that they’ve made to us verbally.”

GSM always was a possibility for STV, especially because of initial interest in the standard from partner Cox. However, a source at one GSM vendor said that selling STV on GSM was always a hard-fought battle.

One factor illustrating that GSM still may form some part of STV’s future is that American Personal Communications, 49 percent owned by STV, is deploying GSM for its Baltimore/Washington, D.C., network, scheduled to launch in December. The service will be Sprint-branded.

APC President E.Y. Snowden said he wants to provide customers with a feature-rich, easy-to-use, proven technology.

“CDMA is in its development stage, and we’ll be looking to see its development take place before we’re ready and confident to switch customers to it or to offer it to our customers,” he explained.

But that’s not to say APC wouldn’t ever use CDMA-based technology in the future as the basis for a separate service from GSM, said Snowden. One APC service, he suggested, could perhaps offer customers nationwide roaming (CDMA), while the other would be more feature-rich (GSM).

An STV spokesman acknowledged that STV will have to work with APC to somehow integrate service offerings for STV and APC customers in the future.

Dianne Hammer is a telecommunications writer based in Denver.


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