Femtocells: A Win-Win Technology for Consumers and Operators

By Alan Lefkof, corporate vice president, Motorola Broadband Solutions Group, Motorola Inc.

Introduction:

It’s no secret that consumers use – and prefer to use – their mobile phones when in their home, even where a fixed-line telephone is available. People, especially younger consumers, have become accustomed to the convenience in terms of mobility and having a single device to communicate, which remembers their contacts and takes and stores their messages in a variety of formats.

Additionally, more people would prefer one number and one device to handle all their communications needs in the home or elsewhere. An October 2007 survey commissioned by mobile content backup services provider, FusionOne, Inc., found that more than half of respondents indicated that their social lives would “suffer” if their mobile phone were to go missing.

Figure 1: Motorola Femtocell Access Point

Most operators agree that a significant proportion of all calls made from mobile phones are initiated indoors. Therefore, providing good indoor coverage is essential to provisioning cost-effective, high-quality and higher-performance wireless voice and data services to consumers.

Connected to the operator’s mobile network via over existing broadband, they have the potential to make mobile communications truly pervasive while delivering some significant benefits to both the operator and end-user.

The Case for Femtocells

The deployment of new technology, new applications and the ever-increasing usage demands placed upon mobile networks provide mobile operators with a range of challenges. At the forefront of those challenges is making 3G coverage as “near ubiquitous” as possible, both outdoors and indoors.

The traditional 3GPP 3G network architecture, including numerous macro base stations, was designed to provide wide-area coverage. It was not designed to scale - physically or economically - to provide effective coverage for individual indoor/residential situations.

It is common knowledge, within the mobile telecommunications industry, that the use of outdoor macro-cells to provide indoor/residential coverage is not an effective solution. In addition to coverage issues and monetary return, there are also practical issues, such as extensive time and financial investment for site acquisitions and build-outs.

By contrast, femtocells that are connected to the operator’s mobile network via existing broadband have the potential to make mobile communications truly pervasive while delivering some significant benefits to both the operator and end-user.

Femtocells deliver a dedicated coverage solution for indoor/residential use, providing operators with a complete package: a small, low-cost, low-power, easy-to-install 3G low-power access point that can be integrated and provisioned into existing macro networks very quickly and support existing 3G handsets and devices.

Pioneering Femtocell Solutions in the Market

Since late 2006, interest in femtocell solutions has increased to the extent that most industry analysts suggest femtocell “deployment” will become widespread in the coming years. According to recent research from analyst firm ABI Research, 40.6 million femtocells will be deployed in home environments by 2011. And IDC predicts that spending on femtocell-enabled services will grow to $900 million by 2011.

Indeed, Motorola announced in November 2007 that it completed end-to-end testing of its 3G femtocell solution and began trialing its solution with a major operator in Europe.

Motorola is pioneering the development of femtocell solutions as the technology plays a key role in continuing our leadership in mobility.   And Europe seems to be the most ripe for the technology.

To meet analyst projections, as femtocells are a consumer-grade product, hundreds of thousands of devices would need to come to market in a short time span. It’s no surprise then, that despite all of the excitement around the possibilities inherent in femtocell technology, there are issues that need to be addressed before femtocell technology and in-home devices become ubiquitous.

Chief among them is cost. The pressure to reduce the cost of femtocell devices is growing. For mass adoption, the cost must decrease for consumers to buy or lease devices if service providers do not subsidize femtocells the way they subsidize handsets.

Making Femtocells a Reality

Not withstanding the obvious requirements placed on femtocells, they must also fulfill a number of other criteria. Among them are:

· Low-impact – Since space may be limited for most households, femtocells must be physically small and ideally aesthetically pleasing. They must also be silent in operation, generate low levels of heat output and be efficient in energy consumption.

· Low RF power – The transmit RF power output of femtocells is low, between 10 and 100 milli-watts or lower power level than many Wi-Fi access points. By being close to the femtocell, the 3G handset is itself able to transmit at lower power levels than it might otherwise have to when on the macro network, thus minimizing the RF exposure to the end-user.

· Capacity – Femtocells are aimed at delivering dedicated 3G coverage to a household with a capacity of up to six end-users within the home environment.

· Access point/Ethernet gateway space – Femtocell technology can be built into cable and DSL gateways to be integrated with existing home networks or offered as a standalone device.

· Easy end-user installation – Like cable modems and DSL gateways, femtocell stations will be installed by consumers and activated through service providers. The operator cannot have a truck-roll for every new femtocell deployment. The devices must be “plug and play” with a minimal amount of intervention.

· Backhaul via broadband – Femtocells utilize Internet protocol (IP) and flat base-station architectures. Backhaul connection to operator networks will be via existing wired broadband Internet service existing in the home such as DSL, cable, or fiber optics, as available. There are no connections to the wider cellular network other than through the IP core. This will also benefit operators by effectively offloading traffic that would otherwise be on the macro-layer. This reduces the load on the core network and lowers the cost of delivering wireless traffic when compared to the macro network.

· Handovers – Current macro RF planning techniques are inappropriate to femtocells. Largely because of the sheer potential number of femtocells located within close proximity, sophisticated algorithms are necessary to ensure that the overall network quality is not impacted by inefficient handovers and wasted capacity.

· Security - The use of the broadband Internet as the network interface poses security risks with its open access; however, there are various approaches to address this issue such as embedding the interface within the IP signalling itself while network security is managed by the IP security protocol.

· Support for worldwide cellular network standards – As femtocells are likely to be deployed around the world, models will be developed to satisfy various needs; however, all products should offer support for their respective and existing (3GPP) UMTS and (3GPP2) CDMA standards, as well as emerging standards, such as WiMAX and LTE.

· Support for existing 3G handsets and devices – Service for existing handsets and devices is a very important consideration for the end-user and operator alike.

· Operator-controlled – Since femtocells operate in a licensed spectrum in which operators must ensure that they comply with the conditions enforced by a regulator, they should feature client software that enables remote configuration and monitoring via an Operations, Administration, Maintenance and Provisioning (OAM&P) system in a similar manner to that used by the macro network.

• New services and applications – As femtocells are likely to become an integral part of the home, managing all communications in that environment; they enable operators to cost-effectively integrate mobile services into triple-play or quad-play service offerings.

• Service Assurance – Operators must be able to maintain reliability and high quality of service that keep customers connected at the network’s edge.

While these criteria and challenges are being tackled throughout the industry, femtocell testing and deployment continue to happen globally. These developments and the industry’s early groundwork lead toward this realization: when technical and commercial challenges are resolved, a femtocell in every home could become reality.