The Power of a

By Wayne Rash  |  Posted 2007-03-18 Print this article Print

Distributed Antenna System "> In the Hearst building, Wi-Fi and wireless use a distributed antenna system that uses a central location for the Wi-Fi access points and for the in-building cell sites. Only the antennas are spread around the building. Basically, the antenna design uses a diplex approach in which signals from each type of wireless communication are joined at the wiring closets and sent together to a set of common antennas on each floor.

The company responsible for the distributed antenna system was MobileAccess Networks, of Vienna, Va. Filatov chose MobileAccess—after looking at a number of possibilities—for its ability to provide both the signal quality Hearst needed and a path for future growth.
"When Hearst said they wanted to be state of the art, they didnt want to just be state of the art when it went in, but five years in the future," MobileAccess president and CEO Cathy Zatloukal said. Zatloukal said the need to support a variety of wireless services now and in the future dictated a design that Hearst could use for new services that might emerge down the road.
"The cabling is the first challenge," Zatloukal said. With older technology, there would be a cable, an access point and an antenna for each point where the building needed service, Zatloukal said. With the MobileAccess approach of having many services served by one cable and one antenna, the installation is cleaner and better-looking. "The main thing was making sure they didnt have an antenna farm, given all the investment that had gone into making it an aesthetically pleasing and green building," Zatloukal said. With the distributed antenna system in place in the Hearst Tower, Zatloukal said the company will need to add only the necessary electronics to support everything from WiMax to metropolitan and municipal wireless networking. "From a design standpoint, it was a group effort in determining what coverage we wanted and what service we wanted," said Jim Bazzano, senior design engineer for Hearst. "We decided to focus on 802.11b and g for now." The company also decided to make sure that the infrastructure was capable of supporting 802.11a if that was needed and that "802.11n is a possibility later," Bazzano said. Click here to read about why Wi-Fi is insecure. Bazzano said Hearst decided to use access points from Cisco Systems in conjunction with the distributed antenna system. Executives also decided to use eight antennas for each floor, even though they probably could have gotten by with fewer, he said. "We wanted to be able to locate things," Bazzano said. "We have over 280 access points, so its a big advantage to have centralized management and access control." The fact that all the access points, as well as the wireless controllers, network switches, servers and other equipment, are located in one place makes management easier. "Its definitely a cleaner solution," Bazzano said. "The access points are all in the closet, [and] theyre all nested together in a centralized telecom room with the LAN switch. It makes repairs much easier." "In this particular instance, the building was very open and very symmetrical, and [the] floor layout is almost identical," said Steve Moses, customer service manager for MobileAccess. "The design perspective is to place the antennas in the center of the floor, wrapping around the building." Wireless capabilities were key in designing the new building, said Chuck Montplaisir, Hearsts vice president of IT. "One of the design parameters we set was we wanted a ubiquitous wireless network for the building," Montplaisir said. "We have a very mobile work force. A lot of people in this building are laptop users. Next Page: Bringing the building to life.

Wayne Rash Wayne Rash is a Senior Analyst for eWEEK Labs and runs the magazineÔÇÖs Washington Bureau. Prior to joining eWEEK as a Senior Writer on wireless technology, he was a Senior Contributing Editor and previously a Senior Analyst in the InfoWorld Test Center. He was also a reviewer for Federal Computer Week and Information Security Magazine. Previously, he ran the reviews and events departments at CMP's InternetWeek.

He is a retired naval officer, a former principal at American Management Systems and a long-time columnist for Byte Magazine. He is a regular contributor to Plane & Pilot Magazine and The Washington Post.

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