To accommodate explosive growth in demand for wireless data, many mobile carriers have begun touting next-generation “4G” networks. But to consistently reach good speeds, especially indoors in densely populated areas, so some carriers are starting to offer small, low-power indoor cellular access points called “femtocells.”
The move from analog to digital to 3G networks was largely a matter of upgrading the technology in cell phone towers. But the explosive growth of smart phone use means that carriers need new ways of boosting bandwidth. One way to ensure high speeds, especially inside buildings where interference is common, is to use small cellular base stations (about the size of a Wi-Fi router) that route traffic over the internet.
AT&T, Verizon, and Sprint have started selling femtocells that can be used in the home to boost spotty wireless reception. Some carriers are also exploring the use of femtocells as a way to improve the performance of the their networks, since the transmitters that are small enough to be installed almost anywhere, from overhead power lines to street lamps and pay phones.
Woo June Kim, vice president of technology for femtocell manufacturer Airvana, says it may be possible to achieve speeds that are 10 times faster than 3G using existing network infrastructure, but he adds, “if you want to increase significantly beyond that, you really need what’s called ‘spatial reuse.’ ” Spatial reuse exploits the proximity of users to a base station–fewer users share each access point, but the capacity of individual access points does not change.
In the past, femtocells have been too expensive for widespread rollout, but femtocell maker Ubiquisys recently developed a $100 unit. AT&T also recently announced that it would offer a $150 femtocell.
Rich Kerr, CEO of Public Wireless, which installs femtocell infrastructure and leases access to it, says that splitting an area of wireless coverage into two smaller units using femtocells increases the wireless capacity by about 85 percent.