Phone’s Impact on AT&T’s Network
By Brad Smith
WirelessWeek - September 15, 2007
AT&T’s wireless unit has changed its network focus from expanding the network to optimizing the customer experience.
Last June before the iPhone launched on AT&T’s network, the nation’s largest operator installed 20,000 additional radios in cell sites around the country, part of a fine-tuning effort to increase capacity in advance of the rollout.
Richard Burns, AT&T’s president of wireless network services, chuckles about some the blogs and stories that “uncovered” how the carrier was preparing its network for the iPhone. He says the iPhone upgrades were the kind of optimization AT&T does all of the time to make sure its products and services perform as well as possible. Of course, the network enhancements for the iPhone, which cost about $50 million and were called Fine Edge internally, were broader in scale than most.
Burns: Must react to data traffic patterns.
Burns, who had been chief integration officer for broadband at BellSouth, came to AT&T’s wireless division as part of the company-creating merger that brought Cingular, AT&T and BellSouth together. His arrival on the wireless network side coincided with a change in AT&T’s network strategy – which was played out in the iPhone launch.
With 64 million subscribers and a network that covers a population of 300 million, AT&T’s wireless network has reached a level of maturity that requires a different focus. No longer, Burns says, is the carrier’s attitude “build, build, build,” but rather “operate, operate, operate.”
“Two years ago, I would have been a builder too,” Burns says. “There were areas to serve, coverage that was needed. Now it’s time to concentrate on operating the network at a high level of efficiency. I happened to be here at that time.”
Network enhancements like those done for the iPhone are helping AT&T’s bottom-line. Subscriber churn, at 1.2% in the last quarter, is the lowest it has ever been and Burns thinks that’s because consumers recognize the network improvements, which showed this year as J.D. Power and Associates placed AT&T Mobile ahead of Verizon Wireless in customer satisfaction (T-Mobile USA was first).
AT&T field technician, Todd Morgan, begins to thin the company’s TDMA network in South Florida.
The merger also dropped several ongoing challenges into Burns’ lap – continuing the consolidation and integration of separate GSM, EDGE, TDMA/analog, and CDPD networks, plus Cingular’s UMTS/HSDPA network. That integration involved 45,000 different cell sites, of which 12,000 have been eliminated (some 6,500 new sites have been added). The CDPD networks have been shut down, while the TDMA/analog networks have been consolidated and are in the process of being shut down next February.
The 12,000 cell sites that were eliminated were the result of overlapping coverage from the networks which came together in the 2004 Cingular acquisition of AT&T Wireless. About 5,000 of those sites went to T-Mobile USA as part of the merger agreement.
Burns also is nearing the consolidation of six separate network operations centers (NOCs) spread around the country. When completed in October, AT&T Wireless will have one NOC in two physical locations (Atlanta and Redmond, Wash.) for disaster recovery purposes.
The six NOCs were a legacy from the old AT&T Wireless, Cingular and regional network days. The problem with so many NOCs, Burns says, is that it created duplication of efforts. The same network problem could occur in different regions and different NOCs would be responding in the same way. Now, he says, “you don’t have five or six people looking at the same thing.”
Instead of concentrating on building out the network footprint now, Burns says his focus is on optimizing network performance, including RF (the radio frequency wireless signal), using technology to help the NOC keep tabs on day-to-day performance, and constantly tuning different network elements. The optimization can include such things as putting in the ability to automatically tilt radios at the cell site locations so technicians don’t have to climb a tower.
This kind of tuning can change depending on geography and time of year, say when trees leaf out in cities like Atlanta. When the trees have lost their foliage, the antennas can be tilted upward more than during the summer, changing the propagation characteristics of the signal. Engineers don’t have to worry about that in places like Phoenix because of the lack of foliage.
AT&T’s network engineers also are doing more “what-if” scenarios to plan how to optimize the network. One example is what impact on customer experience there might be if an antenna is tilted 5° one direction or another. Another example was getting ready for the iPhone launch, because the engineers tried to anticipate where the phone would be used for data access.
AT&T installed the 20,000 EDGE radios around the country (which came out of inventory so there was no additional cost) after an in-depth study of data performance at most of its cell sites. Burns says engineers studied performance data at the cell sites over a 24-hour period and decided if there was high data usage at any time during that period a new radio was needed. Engineers also theorized that iPhones would most likely be used in cell sites that already saw higher-than-average data traffic.
“It turned out we were exactly right,” he says. “We haven’t had anyone bring an iPhone back saying the network wasn't working.”
Apple opted to use AT&T’s EDGE network for the iPhone because it had the broadest coverage both in the United States and the ability to use it widely overseas. “They wanted to widest and biggest market and EDGE makes the device as useful as possible for the broadest number of customers,” Burns says.
Keeping the EDGE network performance at a high level is a continuing task. “Our ability to predict how many iPhone users will show up (in a single cell site) at one time is not perfect,” Burns says. “We know there will be hot spots from time to time. It’s reasonable to expect it will happen. The key is to recognize it fast and do something about it.”
Any time voice or data traffic, or a combination, exceeds capacity, the NOC gets an immediate indication, he says. Engineers can re-balance the radios to provide more data capacity, or vice versa. If that doesn't solve the problem, a new radio can be added in about 24 hours.
Burns also is continuing to prepare to turn off AT&T’s TDMA network in February. It has done that in 21 markets this year (called thinning) as existing TDMA customers migrate to GSM/UMTS.
“There will be additional work done when we turn those networks off but we’re constantly re-engineering them now,” he says.
There’s also the continuing build-out of the UMTS network, which Burns expects will cover 200 markets and 270 million people by the end of the year and will add more coverage in 2008.
Although the network footprint will continue to grow, Burns is watching day-to-day operating metrics closely.
“Our real chance to wow the customer is around the performance of the investments we’ve made,” he says. “We’re always going to be building new sites. We'll follow our customers. (But) optimizing the customer experience through the assets we have has more upside potential than putting in the next 100 cell sites.”