Femtocells, Wi-Fi to play growing role in mobile networks
- 16 February, 2011 20:02
Some people may yet debate the value of femtocells, but the tide has turned: in 2010, the number of femtocells around the world exceeded the number of macrocells, according to the Femto Forum.
Femtocells are small base stations that operators place in homes or businesses to improve coverage and capacity for users. While there is some debate yet about whether femtocells or Wi-Fi represents a better choice, most experts are now saying that the two technologies will work together.
"We're seeing that competitive pitch receding," said Simon Saunders, chairman of the Femto Forum, an association supporting the femtocell industry. Now, many femtocell makers are including Wi-Fi in their products. That way end users can attach to the Wi-Fi network for data services and use the cellular connection for voice. Ubiquisys is one company that introduced new femtocells that include Wi-Fi during the conference.
"In the network community it's not an either or," said Steven Glapa, senior director of field marketing for Ruckus Wireless. "It's 'we'll do femto and Wi-Fi' and all of them added up will address the issue." Ruckus builds Wi-Fi access points that operators can integrate into their wide-area networks.
Toward the end of last year, the number of femtocells in the U.S. reached 350,000, surpassing for the first time the number of macrocells there, Saunders said. Globally, there are 1.7 million femtocells in use compared to 1.2 million macrocells, he said.
The timing is right for even more growth of femtocells because many operators are upgrading their networks to LTE, the next generation mobile technology. At the same time they realize that users want to consume an increasing amount of data. Femtocells can help increase capacity for operators but deploying femtocells requires radio frequency planning. It's easier for operators to plan femtocells into new networks than it is to add them to an existing network.
"[LTE femtocells] won't be new devices that are deployed years after the network is built," said Todd Mersch, director of product line management at Continuous Computing. NTT DoCoMo is one operator that has been outspoken about working femtocells into its network upgrade plans, he said.
Femtocells can also help operators that are struggling with finding new sites for their base stations, an often expensive exercise. Femtocells are physically much smaller than a base station so can hang in many more kinds of locations. "They can disappear into a building," said David Swift, a product marketing manager at Alcatel-Lucent.
Still, for some operators, sticking with Wi-Fi instead of femtocells makes sense. T-Mobile late last year said many of its Android phones would ship with software that allows people to use Wi-Fi to make phone calls and send SMS and MMS messages. That offloads traffic from T-Mobile's cellular network and shifts the expense of backhaul to the Wi-Fi network.
T-Mobile invested in a backend system from Kineto four years ago that lets it manage the Wi-Fi use, including counting minutes of use on Wi-Fi against a subscriber's plan. That may have made the choice to stick with Wi-Fi easier but a company executive said it was a clear choice.
"Femtocells have a math problem and a customer service problem," said Joshua Lonn, director of product development for T-Mobile. From an investment standpoint, buying femtocells would cost T-Mobile tens of millions of dollars, he said. Many T-Mobile customers already have inexpensive Wi-Fi routers that can instead serve as a coverage extender. Also, most smartphones today come with Wi-Fi.
In addition, femtocells can be challenging to install, he said. "They're a pain to set up and a pain to optimize on the network," he said. "Wi-Fi is robust. Why do something as complicated as femto?"
The downside to using Wi-Fi currently is that users still have to actively turn on Wi-Fi on their phones before using it. But both Kineto and Ruckus talked about work going on internally and in standards bodies to make roaming between the cellular and Wi-Fi networks automatic.