Just Another Data Bearer?

Why aren't wireless-service providers using the WAP-over-SMS protocol?

You probably don't use the WAP-over-SMS protocol as a bearer for wireless-data services, instead opting for WAP-over-circuit-switched data (CSD) or CDPD. And because SMS hasn't caught fire here yet, you may not see a reason to change anything. Many other providers agree.

Ken Woo, AT&T Wireless director of corporate communications, said the company is not doing WAP over SMS.

"We have absolutely no plans to, and nobody knows anything about what would happen if you tried to do WAP over SMS," he said. "SMS is a very narrow pipe. We are doing WAP over our CDPD network and, eventually, WAP over the EDGE network."

But there are many benefits of using WAP over SMS for certain applications, and it is something that providers should consider, along with WAP-over-whatever protocol they're using now, because the combo might offer consumers more convenient, faster applications.

Kris Rinne, SBC Wireless vice president of technology strategy, said deploying WAP over SMS is preferred but not easy. SBC Wireless has introduced WAP over CSD in its major markets instead.

"We have not pursued WAP over SMS, primarily because there are only so many priorities you can put on your handset makers' list," she said. "We have been pushing them more for just pure SMS-mobile originated in our TDMA environments, and then aggressively going after GPRS and EDGE deployment with WAP integrated with that. We have done quite a few trials in terms of other SMS applications, we're looking at other potential applications of SMS that would not require WAP."

Why WAP Over SMS? Some say that implementation of SMS as a WAP data bearer is necessary. Why? First, dial-up/connection time is much too slow in regular data mode. WAP over CDPD is an expensive service, and the circuit-switched link is an expensive one to set up. Also, WAP over SMS would allow users to access WAP services while talking on their phones.

According to Steffan Pehrson, Ericsson general manager, mobile Internet enablers, it's better for end users to use WAP over SMS than WAP over CSD.

"Because the accept time to set up WAP over SMS is basically none, you get much faster access," he said. "The problem of course is that WAP over SMS has less bandwidth, which means that the services you would use for WAP over SMS are not traditional Web services."

"You can't overlook the fact that there's a whole delay factor with CSD," said Triona Mullane, Logica device president of technology. "There is the time to set the link up, whereas with messaging, you should see a turnaround of the seconds it takes to send and receive a message."

In addition, WAP over SMS is a viable option for providers because it's faster than a CSD connection.

"If I were an operator, yes, I would launch WAP over SMS, and I would do it smart enough to make services that were tailored for this bearer," Mullane said. "If you launch WAP over CSD, you can get an access time of five seconds, but most operators, when they launch, get an access time of 30 seconds. WAP over SMS could be one second."

Europe and Asia have had phenomenal success with wireless-data-messaging-based services, for which messaging is used as the underlying bearer to do the equivalent of a lot of WAP services today.

"People could do today with short messaging, and quite a lot of the features that people expected to be able to do with WAP are already available with short messaging," she said.

According to Mullane, for certain types of applications, messaging is the only underlying bearer that makes sense today. But she suggests that providers should use both WAP over SMS and WAP over CSD, depending on the application.

"If the application is a stock-quote download, then short messaging is an ideal service to use to send that," she explained. "If you want to set up a longer dialogue, then it makes absolute sense to use a circuit-switched link or CDPD. It's really the nature of the application that will determine which underlying bearer you should use."

CSD is of course better for services that need more bandwidth. But services that would be good to use with WAP over SMS include simple notification or services where you need an acknowledgement dialogue with the application.

"I think operators will build in messaging as part of their core applications and dynamically select between data bearers depending on the application the person wants to do at the time," Mullane said.

Pushing WAP Over SMS As U.S. providers begin to push messaging services, WAP over SMS may get a push of its own.

"You will see an explosive growth in messaging in the next six to 12 months in North America because to date carriers haven't had 2-way messaging enabled," Mullane said. "It's very easy for carriers to say today they're only using CDPD or circuit-switched for their wireless-data solutions because they haven't actually launched mobile-originated messaging. But they are all turning it on over the next few months."

One impetus may be Ericsson's new A2618 handset, which supports the WAP-over-SMS protocol and will soon be available in other markets.

According to Pehrson, many GSM providers have launched GSM over SMS. Those that have been successful are ones that have used SMS for "what it's for" - push messages.

"If you want to have a message pushed to the phone on WAP over SMS, it comes directly to the phone as soon as the phone is on," he said. "If you go for WAP over CSD, you will not receive any push message. The first time you will receive that message is when it's transformed into an SMS or if you go out to surf the Web (store and forward function)."

Push services are one of the key applications of SMS, and one that could be very popular in the United States, Mullane said.

"A back-end push server where I go and decide what information I want sent to me on a regular basis without having to go look for it, that is something that will be very successful," she said.

Although SBC Wireless has no plans to launch WAP over SMS anytime soon, the provider will be pushing 2-way messaging heavily as part of its wireless-data solutions.

"SMS is definitely part of our data strategy, but I see us using that more for alerts and ring tones and some instant messaging for applications that are quite specific to that air-interface," Rinne said. "Instead of focusing on WAP over SMS, which has limitations of bandwidth but is a very efficient use of the network, we're utilizing SMS in our overall data strategy, but we have not focused that WAP development on that portion."

SBC Wireless provides an enhanced level of real-time, customized-information services to customers through its InfoPak service, an electronic messaging system that delivers text news and updates to wireless users. InfoPak offerings include a real-time quote-alert service, weather forecasts and a reminder service.

For now, SBC Wireless is aggressively deploying WAP over CSD, but in the future will it and other providers deploy WAP over SMS?

"SMS is an untapped resource for our customers," Rinne said. "We're continuing to focus on how we communicate it, how we provide it, how easy it is to use, etc. We would not back away from a WAP-over-SMS solution, but we're not making that a priority."