Mobile operators are looking for solutions to the capacity crunch – the expected result of growing demand for high-speed data everywhere. Priscilla Awde outlines industry moves to introduce the standards which will spur roll out and innovation. 

One of the most obvious ways of solving the problem without investing in expensive macro network upgrades is to divert consumer traffic from the mobile to the fixed network using femtocells.

Femtocells are still comparatively new but despite the benefits operators concerned about the management, integration and radio frequency issues involved in adding large numbers of mini base stations to networks, have been pushing for open standards. Responding to the need, the Femto Forum (femtoforum.org), is solving outstanding technical issues and devising standards to support mass deployments and economies of scale.

At the beginning of 2008 there were around 12 different means of connecting femtocells to networks and numerous proprietary systems available from different vendors. The new Iuh standard, expected to be ratified by 3GPP late this year, defines how femtocells are integrated into core networks and supports standardised communications between femtocells and the network gateways. Iuh will be included in release eight of the 3GPP standard which includes LTE – the GSMA’s 4G platform. There are moves to ensure femtocells can be easily integrated into WiMax networks from the start.

Iuh allows operators to select devices independently from the network gateway thereby avoiding being locked into proprietary interfaces. Simon Saunders, chairman of the Femto Forum explains: “We worked with operators to determine what they wanted to achieve with interfaces between femtocells and gateways. Vendors started working on a single interface based on a collapsed architecture making femtocells more intelligent and able to handle voice and data. Operators want units to self tune on the right frequency and power to cover the house and interface with the network but not on the same frequency as macro base stations.

“Vendors can now produce one box to meet the needs of different operators and customers can choose between boxes in different form factors and functionality.”

Eventually femtocells may transform how next generation mobile networks are deployed. By using higher frequencies to deliver targeted high bandwidth where it is needed inside buildings, scarce lower frequencies can be used to extend coverage with a smaller number of macro cells.

Smart femtocells switch between channels to reduce interference and noise helping make networks less crowded and more efficient. “The fundamental technical problems are solved but we must ensure femtocells don’t break the macro network,” says Will Franks, CTO and founder of Ubiquisys (ubiquisys.com). “Intelligent femtocells listen to what’s happening in the macro environment and adjust signals according to a pre-defined set of rules.”

Unlike the CDMA environment, there is huge pressure to deliver UMTS femtocells integrated into home hubs suggests Paul Callahan VP business development at Airvana (airvananet.com). “There is more backhaul capacity in CDMA networks and, since CDMA femtos are using progressive SIP/IMS interfaces to a standard SIP/IMS core network for voice services, there is no equivalent standard to Iu-h. For data, CDMA femtocells use the existing all-IP IOS interfaces.”

As consumer devices, femtocells must be ‘plug and play’ making them easy for consumers to connect and for operators to manage remotely eliminating the need to dispatch engineers. Femto Forum members recently agreed to implement the Broadband Forum’s management TR-069 protocol which standardises secure customer premise equipment auto-configuration and management functions in fixed networks. “Standards open the possibility of selling femtocells via retail outlets,” suggests Mark Keenan, general manager at RadioFrame Networks (radioframnetworks.com). “Operators know how to ship millions of consumer products already and will want femtocells to be ‘plug and play’ and able to be managed within networks.”

Steve Shaw, assistant VP marketing for Kineto Wireless (kinetowireless.com), believes Iuh should help decrease churn and ensure consumers can take their femtocells when they move and plug them into another operator.

Despite the hype the biggest question for operators has been in how to handle widespread deployment and whether investments would be better spent in DVBH or LTE suggests Mark Heath, associate at Analysys Mason (analysysmason.com). “The economic situation has changed and operators want to save costs rather than spend money. 3G is where femtocells will have a significant impact as operators must improve indoor coverage without investing substantially in macro cells. So, anything the Femto community can do to make them more attractive and easier to deploy will be good. In Western Europe approximately 20% of houses have 3G coverage which could be significantly improved by femtocells.”