AT&T Trial Shows Small Cells Bring Nearly Perfect Coverage to Problem Areas

AT&T is constantly fighting to improve bandwidth on its overcrowded network, which has seen mobile data usage explode 30,000 percent between 2006 and 2012. The carrier has found a solution in small cells, which can bring nearly perfect usability to areas prone to dead zones and dropped calls.
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Small cells will help provide additional coverage and capacity in troublesome network areas.Image courtesy AT&T

AT&T is constantly fighting to improve bandwidth on its overcrowded network, which has seen mobile data usage explode 30,000 percent between 2006 and 2012. The carrier has found a solution in small cells, which can bring nearly perfect usability to areas prone to dead zones and dropped calls.

AT&T tested small cells in Crystal Lake Park, Missouri and Waukesha, Wisconsin. In Crystal Lake Park, where the technology was used in a highly populated neighborhood, the small cell increased traffic by 17 percent and also boosted outdoor areas to nearly 100 percent usability. Waukesha was a test in an enterprise environment, specifically a large building dotted with dead zones. The addition of small cells gave the area almost 100 percent coverage and virtually eliminated dropped calls. AT&T did not, however, specify what happened to download speeds after small cells added all those users to the network.

"The beauty of a lot of the small cell-type of technology is we are building out this core infrastructure within our network that gives us flexibility to target a variety of use cases," Gordon Mansfield, AT&T’s executive director for small-cell solutions, told Wired.

Procuring additional spectrum bands is one way networks expand capacity, but in places with high population densities or difficult geographies, coverage can still be an issue. For this, networks like AT&T, Sprint and Verizon are beginning to deploy small cells.

Small cells aren't just one piece of hardware technology, but rather a collective term for cellular coverage solutions that target smaller geographical areas and numbers of people. A device that's 250 mW, for example -- which is fairly low power -- can support up to 32 users and cover the area of a large building. But small cells are available at a number of power levels, so a 5 W one could support 200 users and cover hundreds of square meters, or a 1 W one could be targeted at 10 meters of subway entrance and cover 64 to 128 concurrent users.

A traditional cell tower generally covers a 1.5 km area (although in somewhere flat and rural, like the desert, a tower could cover a 10 km area) and ideally may only have 80 to 90 people on the network at one time. More than that, and bandwidth starts coming down, calls start getting dropped, and users get frustrated.

All the major carriers, including AT&T, are rolling out their small cell technologies over the next few years. Unlike the seemingly random roll out of 3G and then 4G LTE networks across the nation, small cells should start popping up in areas with the most problematic coverage first.

"We have a tremendous amount of data so we can see where we have potential performance challenges within the network," Mansfield said. "We’ll use that data to help guide where we go target the solutions, creating a strategy based on a prioritized list driven mainly by capacity and performance."