All you wanted to know about Femtocells

Or how standing on one leg over your filing cabinet to make calls could become a thing of the past

All you wanted to know about Femtocells
Femtocells solve a common and irritating problem: poor mobile phone coverage within buildings. It's not just failed connections or dropped voice calls - lack of signal also prevents data transactions such as text messages, MMS (picture) messages, and email messages from getting through.

A femtocell resolves this situation very simply. Normally a handset or mobile device connects via radio to the local mast antennae, and then into a fixed network that carries the call on. A femtocell is like a private mast that connects through your broadband connection. Everything then works as normal. How simple is that? Best of all, the cost of this performance boost is a one-off expense.

The closest competition for femtocells are fixed/mobile convergence products using UMA (Unlicensed Mobile Access) standards. These products normally use Wi-Fi or Bluetooth to create the connection when no cellular signal is available. In the UK, the best example of this offering is BT's Fusion phone. The original product, developed with Motorola, was designed to use Bluetooth (and later Wi-Fi) to 'roam' onto the broadband connection in a domestic property, enabling high speed downloads and free voice calls. Outside the property, the phone used conventional cellular connections. Such services require special (UMA-enabled) handsets, and it's fair to say they have yet to really catch on.

Currently in Europe, only Vodafone and SFR have actually launched femtocells to their customers and their focus is very much on the consumer or small business. Large organisations - such as enterprises and public services - will be the next focus.

Femtocells on the other hand, work with conventional devices. The potential demand looks enormous. ABI Research predicts there will be 32 million femtocell access points worldwide by 2011 supporting some 102 million users. That's because the mobile network operators will benefit enormously. From a mobile network operator's perspective, the advantage to offering femtocells is obvious. They extend the company's 3G coverage with absolutely no capital outlay. The customer is paying for both extra base stations, which the femtocell covers, and the (backhaul) network connection, which is covered by the customer's ADSL connection.

The two main commercial suppliers at present are Alcatel-Lucent and Ubiquisys. The latter has supplied the 'Petit' base stations to France's SFR, the second operator to launch a femtocell service in Europe after Vodafone, which launched its service in the UK in October 2009. SFR is Ubiquisys' second commercial customer with Japan's Softbank being its first.

According to Keith Day, VP for marketing with Ubiquisys: 'Most businesses only think in terms of a single femtocell improving in-building voice call coverage. However, today's femtocells are highly intelligent devices that can create their own mesh network to improve 3G reception.'

Day continues: 'Unlike previous offerings, there's no need for a radio engineer. The boxes simply configure themselves. So, suddenly it's an affordable proposition for businesses of all sizes.' Since each femtocell can communicate with other femtocells in the mesh via an existing cabled LAN, they can automatically configure themselves. For example, they might customise the signal power levels to avoid interference. Alternatively, if 3G users suddenly congregate around one particular cell, the others can increase their signal power to spread the load.

It's also possible to tie femtocells into a corporate telephone system (a PABX that is IP based). This means the mobile operator's network still handles all the signalling but data - such as email attachments - can be delivered to a 3G device via the corporate LAN. This process is known as local off-loading.

'Femtocells not only provide better coverage but improved data connectivity. This is important given the reliance employees place on 3G devices such as BlackBerrys or a netbook PC with a 3G dongle,' Day concludes.

What is a femtocell?
A femtocell is essentially a personal 3G base station, which is placed in a home or office. This product extends cellular coverage inside a building, particularly to those parts of a building where a handset receives no signal or has limited coverage.

All that a femtocell requires is a regular broadband connection (usually through ADSL/BT line, although cable is equally viable). Besides power, all it needs is a regular mobile phone.

However, keeping unit production costs down means that the mobile phone networks have restricted these products to 3G phones. The data throughput speed advantages also means that a minimum of a 3G phone makes sense, although higher speed (HSDPA) handsets are supported.

Typically, one single femtocell will support between one and four simultaneous users. Luckily, these units self-configure so that they don't clash with each other or with the normal signal from a nearby phone mast. The most logical place to locate a femtocell would be deep in the heart of a building where mobile phones normally don't work.

'Femto' means one-quadrillionth so adds nothing to people's understanding of what they do, therefore they are often referred to as an 'access gateway' or 'access point base station'.

With the Vodafone Sure Signal product, for example, there's little setting up to do, although Vodafone does require the owner to register (online) the telephone numbers of those handsets that intend to take advantage of the femtocell service.

CASE STUDY: Markettiers4dc
'We're located in a lower ground floor office, which in common parlance means we are in a basement,' Dan Humphreys, associate director with Markettiers4dc confesses.

The company is a broadcast PR specialist, based in London. 'From its business model perspective, being located in a building with no cellular signal makes sense because it effectively "soundproofs" the office,' Humphreys adds. 'The premises have proved ideal for when Markettiers4dc needs to record an audio track for one of its clients, for instance. The downside to being located in a soundproofed environment is that there's absolutely no cellular signal available.'

Humphreys estimated there are around 60 people working in these 'subterranean' premises, whose mobile phones would typically stop working. The problem has been cured, however, by rolling out femtocells supplied by Vodafone. The product is marketed as the Vodafone Sure Signal and is available to SMEs for a one-off cost of £42.56 (or £4.26 per month for 12 months). It is also available on 24 month plans for a one-off cost of £102 (or £4.26 per month for 24 months). Suppliers such as Expansys offer discounts for five units or more. The call and data charges for using a handset via the femtocell is exactly the same as connecting via a regular phone mast.

Given the need to register each 3G handset to take advantage of the Vodafone Sure Signal with the network operator, some Markettiers4dc employees have taken to registering their best clients' numbers so they work, too. [This only works if they are also on Vodafone]. However, as each femtocell can hold around 30 telephone numbers, there is sufficient room for this practice.

'Now everyone can potentially get a connection,' Humphreys enthused. 'Why would we not get them [femtocells] given that advantage? It's a no-brainer.'

What deploying femtocells has effectively done for the com
Written by Wireless magazine
Wireless magazine

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