Shelters/Cabinets: The Decision

Your options are endless when it comes to housing cell-site equipment. Enclosures can be as big as a garage or as small as a breadbox. They can be no-frills boxes that provide basic protection or offer exteriors nicer than some homes. Established carriers that followed the trend from larger to smaller sheltersare planning now for future housing. Some suggest that the larger shelters better accommodate their equipment needs. Others are moving toward less expensive cabinets to accommodate network deployment costs.

THE EVOLUTIONWhen wireless was born, cabinets were not even an option, said Bill Mayberry, BellSouth Cellular director of technical operations. Fiberglass shelters were the only available enclosures, and were, for the most part, lightweight and cost-effective.

"In the early days, traffic requirements at the cell sites were pretty low, so the shelters were sufficient to get us started," he said.

As the need for more equipment developed, concrete shelters became a better option. At one point, Mayberry said, concrete shelters were even more cost-effective than fiberglass. Most carriers that are at least five years old have plenty of large shelters in their networks.

Also in the beginning, carriers' backhaul was predominantly through microwave radio, so radio equipment took up a lot of space in enclosures. Now that carriers such as BellSouth Cellular are experimenting with T1 leased lines for backhaul, cabinets are not as crowded as when they first came on the market. Because electronics have improved and decreased in size, carriers can place the same radio capacity in a cabinet today that that they would have needed a 10'x10' shelter to accommodate before.

CONVERTING TO CABINETSAfter using and testing various shelters and cabinets through the years, BellSouth Cellular plans to stick with cabinets for the long haul. The company attributes its ability to get sites up and running in a couple days in part to cabinets.

"The real advantage is time," Mayberry said. "When you are trying to deploy your network in a hurry, cabinets can get you up and going quickly."

Cabinets also are ideal for co-location situations, he added. They take up less space on the ground, and when three or four carriers share a tower, putting multiple shelters at the base is a waste of space.

"You can squeeze in a third or fourth cabinet on the ground a lot easier than three or four shelters," he said.

Although it is possible to share one shelter with co-location partners, Mayberry does not agree with sharing shelters. It is hard enough for carriers to share a tower, he said.

"Physically allowing them access to a shelter and equipment is a bit much," he said. "I don't know if the industry would get comfortable with that except in a rare case where that was the only option. How much do you really trust your competition?"

A third advantage to cabinets, Mayberry said, is that you can establish your power company and T1 lease facility demarcation points outside the cabinet. Because 80% of BellSouth Cellular's network problems are power- and lease-facility-related, the power or telephone company can repair the problem without having to go into the cabinet.

"If you have a shelter, you almost always have to call a technician to meet with the phone company to go inside," he said.

STICKING WITH SHELTERSAlthough WirelessNorth is not a cellular carrier, it has tested its share of shelters and cabinets since its launch five years ago. Thomas Horton II, WirelessNorth CEO of the technology services group, said the company chose shelters over cabinets to help protect technicians and equipment from extreme weather conditions in markets such as International Falls and Duluth, MN, known as the two coldest places in the country.

Temperatures in northern Minnesota often plummet below 0*F. Horton said cabinets are ineffective in such conditions because as soon as you open the door, the cold air rushes into the cabinet and kicks off the ambient temperature switch, even if nothing is wrong. Shelters, however, are heated inside so technicians can work comfortably without cold air shutting down the system. Some carriers place tents over their cabinets and warm the tented air with a heater to solve the problem. It takes a lot of effort to set up a tent and heat up the air just to change out a card or recalibrate a base station, he said.

"You have got a tech that is out there with $15,000 or $20,000 worth of test gear, and he has to lug that around and use it in the cold?" Horton said. "It won't function right. If anyone in the northern region asks for an opinion on shelters or cabinets, I would, without question, say go with a shelter."

Cabinet advocates note price as a reason to choose cabinets over shelters, but Horton said he can buy a shelter, have its vendor install all of his equipment and put down a foundation for less money than it would cost him to buy and install a cabinet.

As for co-location, WirelessNorth is not opposed to letting other companies into its shelters. Instead, it regards its shelters as an additional revenue stream. Possible co-location partners include paging companies, local police departments and emergency services.

"Some places in Minnesota are out doing a 911 initiative, so if they needed to put a signal relay or repeater type of system in for their radios, they could do something along those lines," he said. "If there is a law enforcement agency or emergency system that wants to co-locate in our shelter, that is just another level of security for us."

Even BellSouth Cellular's Mayberry, who has an affinity for cabinets, admits that shelters are the best option in some situations.

"If you decide to make a certain site a backhaul hub site where you have significant microwave coming in, and you must multiplex that bandwidth together and take it back to a switching office, you might want a shelter there," he said. "In that situation, you need to house the radio equipment as well as microwave gear."

Shelters also are ideal if you anticipate that a site's traffic requirements will increase in the future. If you go with a cabinet, you would have to add cabinets as the traffic grows.

"Pretty soon it starts to look like a graveyard with all these cabinets sitting out there," he said.

Horton pointed out that if a carrier uses cabinets and wants to expand a site, it often must add concrete pads. Not so with shelters.

"If we want to do an expansion, we don't have to do anything else to the site," he said. "We just push another BTS bay into the shelter, the technicians wire it into the rectifier system, and we are done."

Mayberry argued that adding concrete pads is not an issue at BellSouth. The company initially lays out the pads assuming there will be growth and designs its sites for future cabinets.

A HAPPY CO-EXISTENCEAirTouch Cellular still implements and deploys shelters in RSAs and in places where cabinets do not offer the power output it requires. In metro areas, however, the company is trying to bring down overall costs by installing cabinets, said Greg Clausius, AirTouch network director of the northwest region.

Clausius noted that AirTouch's infrastructure vendors only offer low-power versions of cabinets, and in some cases they do not provide battery backup and other things the company needs in its remote sites.

"Most of the infrastructure providers developed cabinet sites for PCS carriers from day one, then came back and looked at the cellular sites and are working on solutions," he said. "We are still working with Lucent and Motorola to find the right fit, but they are not yet in a position to provide us with the cabinet solutions we are looking for."

In some instances where AirTouch has tried cabinets, they have worked well. In other areas, they leave something to be desired. AirTouch's CDMA digital technology requires multicarrier applications, and many cabinets are only single-carrier.

"In the instances we have used them, they have worked fairly well, but they have kind of a limited deployment," he said.

Even if AirTouch sees the day where cabinets meet its every need, Clausius doubts the company would ever get rid of shelters completely. AirTouch has invested a lot of money in its shelters.

"As long as they are still working efficiently, there would be no reason to do away with them," he said.

* C&D Technologies' fully integrated rack system enables carriers to reduce the time it takes to engineer, designand deliver a power plant. The IRS uses 48V, 30A rectifiers with front 150Ah access batteries. C&D also provides and ships an integrated package, including batteries and a power plant, with a custom-designed rack to hold both.

www.cdpowercom.com or 215-619-7804

* Rittal's QuickRack Value Pack includes a variety of cabinets with heights from 24U to 47U, including a front-glass viewing door, a vented rear steel door, 19-inch mounting angles and horizontal rail supports. The QuickRack Power Pack includes the Value Pack's standard features, plus an 8-outlet power strip and a roof with fan tray.

www.rittal-corp.com

SHELTER PROS: * Closed to the elements

* Can add racks gracefully

* Room to install electronics if using microwave for backhaul

* Climate-controlled

*Room to expand power and add capacity

* No need to add concrete pads

SHELTER CONS: * Takes up space

* Slow to install

* Often heavy

* Decreased security if shared with co-location partners

CABINET PROS: * Takes up little space

* Quick installation

* Lightweight

CABINET CONS: * Exposed to the elements

* Offers little extra space

* Early cabinets faced condensation problems in warm areas

* Must add concrete pads if expanding