Waiting for WIN

By now you know that the beauty of prepaid appeals to more than just credit-challenged individuals. You probably already offer prepaid to your subscribers, or you are considering it. But with so many solutions out there, the question in prepaid no longer is who, but how?

Although prepaid handsets are one way to offer the service, the industry is moving toward network-based alternatives. Two main types of network solutions are available: trunk-based, (adjunct switch-based) solutions and WIN-based (IN-based) solutions. William Taliaferro, Corsair director of product marketing, said trunk-based solutions work like this: A customer makes a call. The voice and data portions of the call travel first to the cell site, then to the MSC. They then pass through T1 or E1 voice trunks to the adjunct switch and finally to the computing platform, which looks up data about the caller to see if he has enough money in his prepaid account to make the call. Wyant McAvoy, Airone/AirTIME Technologies director of marketing, explained how the WIN solution differs. The call is still passed to the MSC, just as it would be using trunk-based technology. However, the voice portion of the call is held in check briefly at the MSC and never is passed to any adjunct switching platform. Meanwhile, SS7 data flows through the service control point (SCP) to the appropriate signal transfer point and, when roaming, with the HLR to look up data about the caller.

Both men agreed that WIN-based solutions save money on equipment. Taliaferro said, for example, that a carrier using a trunk-based solution would require 4,000 trunks and 4,000 ports to connect the MSC to the adjunct switch if it had 200,000 prepaid subscribers who make two 2-minute calls a day at peak time. If that same carrier used a WIN solution, it would require only 60 inbound trunks and 60 IVR ports.

SETTING THE STANDARD So why aren't more carriers moving to WIN? For one, the WIN Phase II standards, which will support prepaid, location-based services (beyond 911) and premium rate charging, remain undefined by the industry. Jeffrey McLaughlin, Boston Communications Group Inc. (BCGI) product manager, said the WIN Phase II standards create the call flow, or order of the messages that the switch will be sending to the SCP. WIN Phase II also standardizes what the SCP needs to do with the messages and how to use the intelligent peripheral.

Wireless industry representatives have been meeting to agree on what those standards should be. Larry Rybar, Bell Atlantic Mobile director of WIN development, said the WIN Phase II standard for prepaid is scheduled to be ballot-ready in June 1999, and a final standard is expected in the third quarter of 1999.

Similarly, GSM providers rely on CAMEL, a different standard protocol set by the International Telecommunications Union, said Felix DeSouza, Omnipoint manager of enhanced services. Like WIN Phase II, CAMEL 2.0 will offer more features and capabilities. It will allow true mobility and the ability to offer prepaid in a roaming scenario, he continued. Vendor implementation of CAMEL 2.0 will begin in the fourth quarter of 1999.

Without these Phase II standards defined, how is it possible that some wireless carriers already claim to offer a WIN-based prepaid service? Rybar said these carriers are offering prepaid today using proprietary solutions, in advance of the standard. Glenayre, for example, is developing IN solutions with specific switch manufacturers as a temporary solution.

"Our strategy is that it will work until they come up with a protocol," said Michael L. Gulledge, Glenayre vice president of marketing.

Mary Stanhope, Priority Call Management director of product marketing, said service-node solutions are a flexible temporary step to WIN.

"There are many standards out there, and every carrier has a different solution for those problems," she said. "Because a service node is self-contained, it has a flexible interface which really allows you to hit that quick time to market."

Another strategy is to take advantage of present Integrated Services Digital Network User Part (ISUP) and SS7 signaling to develop an operational prepaid WIN now with the capability of meeting WIN Phase II standards once they are established, said Dean Keil, Airone/AirTIME Technologies president.

Several vendors have taken this approach, but McLaughlin noted that one problem with today's proprietary WIN solutions and eventual WIN Phase II-compliant systems surfaces when subscribers try to roam. If their home markets are WIN-compliant, and their serving markets are not yet, then the system will default to the lowest common denominator, in this case, the trunk-based system. The subscribers cannot roam unless the serving markets' trunk-based systems already have roaming capabilities. But if the home markets and serving markets both are WIN Phase II-compliant, customers will be able to roam seamlessly.

McLaughlin explained that the WIN Phase II standards will create the triggers for prepaid services. Rybar added that WIN Phase I, which is almost complete, addresses only some of the triggers that allow the switch to communicate with a SCP.

Omnipoint and Triton PCS are taking advantage of proprietary prepaid offerings even though their customers cannot roam. Until the standards are in place, however, other carriers such as BellSouth Cellular are being more cautious.

"We and other carriers are pushing the fast track through a number of organizations, including CTIA, UWCC and TIA, to try to get WIN Phase II standards set up so we can have a WIN prepaid solution," said Jeff Battcher, BellSouth Mobility manager of media relations.

WEIGHING THE FACTS If you plan to buy a WIN solution today, make sure it can grow with your subscriber base. You also should ask prospective vendors how they plan on becoming WIN Phase II- or CAMEL Phase II-compliant when the standards finally are defined. A vendor waiting to see what develops is not necessarily behind its competitors. BCGI, which offers a non-WIN prepaid product right now, is deeply involved in the WIN Phase II standards development so that its new offering will be 100% compliant. Other vendors are adopting the same philosophy. Rather than going for a proprietary solution, InterVoice, which offers a trunk-based service node solution, is waiting for the WIN triggers to be standardized, said Kristi Spears, InterVoice senior manager of industry marketing.

"If I am using a proprietary solution between my platform and the switch vendor, once I go outside that switch vendor to another one, they are not going to recognize those triggers," she said.

There is no doubt that the wireless prepaid market offers a wealth of opportunity. Once the WIN Phase II and CAMEL Phase II standards are set, IN-based solutions are going to be the choice of the majority. But when the time comes for you to enter the market, proceed with caution. McLaughlin warned that even the new WIN Phase II standards don't address everything.

"While the WIN messages will tell the SCP to process a prepaid call," he said, "it does not address if the system should support 1, 2 or 100 rate plans for the call, or how to record this data for reporting back to the carrier."