Atlanta's airport is now saturated with wireless connectivity, serving travelers and employees.

In January, Hartsfield-Jackson Atlanta International, one of the busiest airports in the nation, threw the switch on the second of two wireless networks that blanket all concourses and gates. The system uses fiber, shielded coaxial cable and hardware from LCG Wireless to distribute cellular signals from carrier base stations to ceiling-mounted antennas throughout the airport.

The cell coverage complements an airport-wide public wireless LAN (WLAN), which went live last October.

"We needed an infrastructure to support voice, video and data services throughout the entire airport, both wired and wireless," says Lance Lyttle, the airport's CIO. Users include travelers, airport tenants such as airlines, concessions and airport employees.

The solution was to create two neutral host systems. The airport acts as a landlord, building and maintaining both networks, which can be used by several carriers or service providers.

Every nook and cranny

The idea behind distributed antenna systems (DAS), such as that of LGC Wireless, is to bring high-quality cell signals to every nook and cranny of large structures. For Hartsfield, that means covering nearly 6 million square feet. Today, Cingular, MetroPCS, T-Mobile and Verizon offer voice and data service over this DAS infrastructure. Some have begun to deploy advanced 3G services over the system.

The carriers installed their base stations at an airport site dubbed the telcom hotel. There, the radios are plugged into LCG's Main Hub, which converts the radio energy into an optical signal. That signal runs through a fiber web to remote hubs, which convert the signal back into radio frequency energy. Shielded coaxial cable carries the signal from a hub to several remote access units, which are like access points for cellular, mounted in the ceiling to cover a specific area.

The deployment was straightforward and smooth, says Daver Malik, wireless voice engineer for the airport's IT group. Technically, the main challenge was making sure the cell signals, covering different parts of the spectrum, didn't interfere with each other, Malik says. LGC's architecture minimizes the impact if any DAS component fails, and the blades in the Main Hub can be quickly replaced if necessary, Malik says.

The DAS infrastructure also will be used by city, state and federal public safety staff and emergency responders. The 851-869MHz band is reserved for this use, so emergency crews can sidestep the public cellular bands.

Pervasive wireless LAN

The WLAN also was straightforward, though it entailed laying a lot of new Ethernet cable. The cabling connects 151 Cisco 1230 802.11b/g access points to Cisco 2000 and 3000 switches, says Dennis Rose, the airport's technical services manager.

Following Cisco's acquisition last year of Airespace, which helped pioneer the use of WLAN switches or controllers, the airport IT staff launched a redesign of the WLAN. A controller-based architecture creates a central point for securing and managing large WLANs.