Data QoS: A Wake-Up Call

Carriers must plan today for better data networks tomorrow.

Forward-thinking carriers should heed today's voice-service problems as a signal of what to avoid when deploying future wireless-data services. Think of it as a wireless data wake-up call.

The 3G wireless networks of tomorrow will move faster and support tens of millions of new users. In this future wireless-data scenario, quality of service (QoS) will become increasingly important. Just as customers complain of dropped voice calls today, they won't stand for broken wireless data promises.

"Clearly, with (wireless) e-mail, there could be a few-minutes delay and it wouldn't seriously hurt the end user, or the end user might not even know," said Andrew Cole, head of the mobile wireless practice at Adventis, a Boston-based consulting firm. "But for time-critical applications like location-based services, telemetry or gaming, that's a big problem. There are a lot of applications that will depend on real-time interactivity for which quality of service is very important."

Wireless data QoS is being addressed by carriers today. However, their efforts - just like the technology - are still in the early stages.

All the carriers interviewed for this article said they would strive for a high level of QoS for data services, just as they do today with voice. But the field is new, and measurements for data quality are not yet standardized.

"It is new territory for the wireless industry in terms of what are those key measurements and how do we select them and how do we evaluate them," said Kris Rinne, Cingular vice president of product and technology development.

In November, a group of industry representatives gathered to discuss the subject of wireless-data metrics. The meeting was organized by Telephia to begin to define standard measurements for wireless-data service quality and usage. The first results will be released in early 2001.

Telephia will provide regular measurements of wireless Internet performance including connection times, download speed, transaction times and success rates across wireless Web sites, carrier networks, devices and geographies.

Data: A New Network Challenge Although some coverage and capacity issues related to wireless data are new to the industry, others have been around since the beginning. And the main way to ensure calls of any kind are initiated and sustained is to build a very dense network of cell sites.

"The carriers privately acknowledge that they have some work to do," Cole said. "A number of them are working on their networks. However, most of the enhancements seem to be tinkering, as opposed to a full-blown strategy to create very robust quality-of-service metrics. For example, Orange makes a big point of the fact that they've got more cell sites than anyone else, and it's true that their quality of service is pretty spectacular. To my knowledge, nobody has done that here in the U.S."

Although U.S. carriers may not be there yet, they are constantly striving for improvement.

"In terms of quality of service for 3G data service, we're going to be really focused on making sure that when a session is initiated, it stays up and isn't dropped and that when they want to initiate a session, the network is available for them to do that," said Oliver Valente, Sprint PCS CTO.

When studying data transmission, Valente said he would look at latency, dropped or blocked calls, busy periods, average hold times and average session length.

"Another key metric will be activity factor," he said. "Many times, people are spending time looking at what's on their screen, versus actually transmitting data. During the lulls we will be able to support other people."

Another potential way to optimize data networks is by offering variable throughput rate plans.

"If one customer's paying more to get higher speeds, you would put someone else on a lower data-rate plan at a lesser priority," Valente said. "We are looking at that. The 3G 1X standard calls for about 14 different data rates."

Initially, 3G 1X will be rolled out with only one available throughput rate, but eventually, Sprint PCS may add the ability to support priority access.

"We are talking to vendors about this area and how to make sure we offer those kinds of capabilities," Valente said.

Cole agreed that offering variable throughput rate plans is a viable way to optimize future data networks.

"At the moment, we have a voice network that gives equal treatment to all, so to speak, as opposed to what we need (for data), which is variable throughput, variable quality, variable handoff quality and so on," he said. "It will get there, but I don't see a whole lot of investment happening like there needs to be."

Network information that allows carriers to detect and understand the needs of a user in a given cell will allow them to allocate spectrum and QoS to individual users.

"There are lots of techniques, but network intelligence is to my mind the most important," Cole said. "And you will see dramatic improvement where it is deployed."

Striking a Balance On many levels, deploying successful wireless-data services in the future will involve tough decisions for carriers, said John Arpee, ScoreBoard CTO.

"If operators are trying to do this cost effectively, they are going to have a challenge," Arpee said. "Whenever you deploy a service, the first customers have it great because there's very little load on the network. But then, as you have more traffic, you're constantly making trade-offs between your capital investment and the quality of service."

If carriers make the right decision - which appears to involve multitiered service levels and an IN - customers will experience few, if any, service interruptions.

"When I think about how I use e-mail, most of the time, I'm lucky if I get to it by the end of the day," he said. "A delay of half an hour is no big deal. But if I'm on the road, and I'm waiting for directions to the customer's office, I want that right now. That may be an opportunity for different grades of data service. If you define grades of service in terms of bandwidth, that's one way. But another way of doing it might be delay."

As a result, carriers may find it beneficial to offer one plan guaranteeing 10-second delivery and another with 1-hour delivery.

"The trade-offs are pretty standard in the world of data for us," said Edward Salas, Verizon Wireless vice president of network planning. "It's really a trade-off between throughput and delay. What you're trying to do is balance what you're trying to optimize for. What's different about the world of data is that, given the diversity of users out there and applications, what's good for one application may not be good for another."

The ultimate goal for carriers is a network sensitive enough to determine those requirements on its own.

"That kind of processing power theoretically exists and could be developed into that kind of capability," Salas said.

Learning From Experience One thing carriers have learned about wireless data with their first offerings of wireless Internet access is that the Internet is unpredictable. Although some computer users are used to fickle dial-up connections at home and at work, they may demand more from a wireless service. And savvy carriers will market wireless data intelligently.

"The complexity of Internet-based services is higher than our traditional circuit-switched environment, where we control all of the resources, A to Z, in terms of the customer experience," Salas said. "Now a customer can conceivably hit the Web. And Lord knows there's no standard for quality of service on the Internet. The end-to-end experience is a little more challenging to control because we don't manage 100% of the resources. So you've got to be conscious of a lot more things and be a lot smarter in how you communicate to a customer."

Cingular's Rinne said it's important to define wireless-data services correctly, so consumers aren't disappointed.

"We're positioning wireless data as access to the information you need, when you need it on the device you want it," she said. "We're not calling it wireless Internet. It is important for us to not oversell or over-commit it."

Although carriers don't control the Internet, they do control their own networks. And as every mobile-phone user knows, those networks do not provide seamless service all of the time. Accordingly, carriers are investing heavily to ensure QoS now and in the future.

"There's a combination of things that contribute to holes," Salas said. "We in the industry and here at Verizon, have spent a lot of money to continue to develop the networks, to build them and create a more dense network that would permit what we would hope to be seamless service. Easier said than done. It's a never-ending story. It's just going to continue."

As wireline expectations increase, WIP will help the wireless Internet keep up.

The biggest stumbling block on the path to wireless Internet success could be the Internet itself. First, it is the one thing wireless carriers cannot optimize; they don't control the Internet. Second, the Internet communications protocol TCP/IP doesn't translate well from wireline to wireless Internet, according to Ed Acosta, BroadCloud Communications president & CEO.

To solve this second problem, BroadCloud has developed a new set of communications rules called wireless IP (WIP) that Acosta claims will double the reliability of wireless-data services and make them operate 10 times faster. And WIP will work with current and 3G wireless networks.

"The bottom line is that cellular voice telephony has been around for 20 years now," he said. "And we still have major problems with calls being dropped, calls being blocked, fading that causes calls to go away momentarily. That is the voice-side manifestation of the lack of reliability. It's only acceptable on the voice side because your brain is fast enough to fill in the blanks. On the data side, with computers, it is unacceptable because computers have neither the power nor the intelligence to fill in the blanks. Those same reliability problems that we experience every day on the voice side exist right now on the data side, and will wreak havoc on data communications including wireless Internet. They must be resolved, otherwise there will never be a meaningful wireless Internet."

Acosta said today's wireless Internet services represent a "good first effort" that is being held back by inexperience and underdeveloped data networks. He said carriers are moving to correct these problems, but considering there have been problems with voice service for 20 years, data problems will persist as well.

Moving beyond the basic challenge of wireless-network density, there are issues of compatibility between the Internet and wireless networks.

"The core challenge that interferes with reliability of (wireless Internet) service is the fact that the traditional Internet protocol suite is being used with wireless networks," Acosta said. "The traditional Internet protocol suite was never designed to work in the wireless environment."

This is a major reason wireless Internet users experience interruptions in service. And although carriers don't control the Internet, they can control how people communicate over the wireless Internet.

"The wireless Internet protocol is an alternative to TCP that is specifically designed for use in the wireless environment," Acosta said. "(WIP) is useful for any digital wireless-data-packet network."

But before you sigh with relief, remember that just as 3G networks begin providing 384kb/s data services, wireline expectations will have leapfrogged again.

Acosta said BroadCloud's enterprise customers already are demanding wireless Internet connection speeds comparable to the 1.5Mb/s DSL and 5Mb/s cable modems available on the wireline side today.

As wireline expectations increase, WIP will help the wireless Internet keep up.

"Not only will it (WIP) keep up, it will probably improve," Acosta said. "The exciting thing is, after six to seven years of research and development of this stuff, we can honestly say that we have only scratched the tip of the iceberg."