Femtocells could become headache for E911

Femtocells, otherwise known as home base stations, have become the mantra for the mobile wireless industry as operators worldwide see them as important tools to expand mobile coverage and offload peak traffic. But what could be a boon to operators could become another headache for E911.

According to ABI Research, the femtocell market is primed to grow from just under $72 million in 2008 to more than $1.8 billion in 2013, with a compound annual growth rate of more than 300 percent. With potentially thousands of mobile customers buying these little boxes to boost their coverage and with a large share of 911 calls coming from mobile devices, the ability to identify mobile call locations when routed through femtocells has the potential to be problematic.

While femtocells are designed to be kept in a fixed location such as the home—theoretically making it easier for 911 officials to pinpoint a location—many of the early femtocells in the marketplace today include a GPS antenna. As the range of these antennas increase, callers could be far from the actual base station, making it difficult to accurately pinpoint them. Moreover, the fear is that some customers may move their femtocells from location to location, causing 911 services to route calls according to the original location since that is the location registered with the operator.

“The location of a femtocell has to be known accurately to be sure it is radiating in the right license,” said Natasha Tamaskar, vice president of product management and marketing with NextPoint Networks, which makes gateways that receive femtocell signals. “Calls could be routed to the wrong PSAP.”

Other potential problems stem from the fact that many femtocells will ride on top of a wired network connection such as cable modems or DSL lines in the home. What happens in a power failure? And femtocell makers have to ensure that the 911 call gets priority over the video download.

“There are so many different types of traffic running on these wired networks. What one has to do is prioritize 911 over others,” Tamaskar said.

In addition, customers will demand encryption of their calls. How will that impact a call to 911 if the caller is not the authorized user of the device?

Fortunately, femtocells aren’t fully standardized yet, which means the industry has the opportunity to address these 911 issues in the standards process, Tamaskar said. NextPoint is part of the Femto Forum, the industry group developing standards for femtocells, and is advocating an emerging standard for femtocells called lu-h, which will address standards for the integration of femtocells within the core network, along with the aforementioned security and E911 issues. The Femto Forum hopes to complete the standards and include them in existing mobile technologies by the end of 2008.

Until then, those customers opting to buy pre-standardized femtocells, such as those offered by Sprint’s Airvana femtocell service, simply shouldn’t expect landline-caliber service.