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Preventing the coming collapse of cell phone networks

Europe’s mobile wireless networks could collapse within three years’ time due to the increase of users who have smartphones and are connected to the Internet. Two projects funded by the European Commission, one of which is developed by researchers at the Polytechnic University of Catalonia, are already working on technology that will prevent this breakdown.

PATRICIA MORÉN | AUGUST 30TH, 2010

The new generation of smartphones offers users a large number of applications such as the use of e-mail and Internet connections, which can be used simultaneously. But these services for users are causing an increasing number of traffic jams on cell phone networks in urban areas as they lead to a huge jump in data flow. This was not the case with conventional cell phones, which were only used to make calls and send and receive text messages.

Currently, the European country with the most users of smartphones is Italy, with 15 million, while Britain, in second place with 11 million, is the country that has experienced the strongest growth in the use of this product in the past year with an increase of 70%, according to comScore.

If these high rates of the use next-generation phones continue to rise, it is expected that by 2013 there will be a collapse Europe’s mobile wireless networks. This is an average estimate for the continent, said Josep Vidal, professor of the Department of Signal Theory and Communications of the Polytechnic University of Catalonia (UPC). Vidal is also director of the Research Group on Signal Processing and Communications of the UPC that coordinates the European project Freedom, whose goal is to design technology that prevents the coming collapse of cell phone networks.

The Freedom project is made up of a consortium of eight partner institutions. Along with the UPC they are the Università di Roma La Sapienza , the Universitat Tècnica Txeca, the Commissariat de l’Energia Atòmica of France, and the companies Dune SLR (Italy), Telkom (Indonesia), and Sequans and Siradel (France).

No more base stations

A possible strategy for addressing the network overload problem would be to increase the number of base stations (the dreaded cell phone masts), of which the city of Barcelona now has one every 600 meters to kilometer, said Vidal. But this solution has several drawbacks.

First, more antennas would be very expensive for operators, who would have to pay for the placement and cable connections since cell phone masts are connected by cable or telephone networks in cities. Second, many citizens are against the placement of antennas on their roofs or near their homes due to their alleged health risks, even though scientists have not yet been able to establish that there is a direct cause-effect relationship between the proximity of antennas and the development of any disease.

Finally, the third disadvantage for adding more base stations is that "almost all traffic from mobile wireless data is generated inside homes. Smartphones are used in indoor environments, offices, bars and shopping centers and in these places signals could not be easily received. These areas do not have very good coverage, and we have to do something to improve this”, Vidal said.

To this end, in recent years there has been a reduction of the areas assigned to each base station, which has increased the transmission rate of wireless systems. But now this development can not go further due to all the drawbacks already mentioned. The solution defended by experts to improve both the coverage and the provision of transmission services for high-speed data transfer at an acceptable economic cost is the use of smaller base stations that will serve smaller cells, the so-called femtocells.

The near future: Home mini-stations

The Freedom Project, coordinated by the UPC, and is part of the Seventh Framework Programme of the European Commission (EC), which is endowed with 3.45 million euros and will run for two years until 2011. The project was created precisely to develop these low-cost mini-stations for cell phones designed to be installed in the interiors of buildings, whether in a private homes, apartment buildings or shopping centers. In contrast, another project, BeFEMTO, also promoted and financed by the EC and which will last for three years, is working to install them in other places such as buses, trains or forms of transport.

One possible solution are femtocells, mini-stations for the home or office These mini-stations are wireless devices that share a wireless spectrum of a licensed cell phone and which only cover an area of 30 to 50 meters and connect standard cells phones to the network of a mobile operator, using the connection of an ADSL network or fiber optics. They also have a lower power usage of about 20mW, which is five times lower than the power of ADSL WiFi router. "They will be similar to a wireless router", said Vidal.

Currently, some networks are already deployed, including the Japanese company DOCOMO, which operates under the principle of mini-stations and femtocells. But it is expected the massive deployment will come in 2012-2013.

THE MINI-STATIONS

The new technical solution that is being prepared based on the overall development of mini-stations also features a series of challenges that engineers are dedicated to resolving. The main one is the fact that if any individual can install a mini-station at home, without any control by telephone companies, this could increase the risk of interference. "We must ensure that these mini-stations are able to detect the interference of others and adjust their transmission parameters or operate independently, without any planned intervention of an operator, to prevent this from happening. If we do not, the operation network will be worse", said Josep Vidal.
Moreover, operators have an interest in all this because with the mini-stations they will save the costs of electricity, which will be borne by the user. Everyone will pay for and install a mini-station at home, just as is now done with ADSL, i.e. "the user will not pay more to improve telephone coverage, because these routers will probably be provided by the operator, but they will pick up the electricity bill," said Vidal.
Despite this increased spending, the user can benefit in other ways, for example, from location-based services. For instance, it is possible that when a child arrives home, the mini-station could send a text message letting the parents know, said Vidal.

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