by Per Kreuger
More dynamic and less resource-intensive: Researchers at SICS have developed a new solution to determine mobile phone positioning.
Communication is becoming increasingly mobile, but tracking the location of individuals within networks is quite a difficult task. As researchers at SICS began analyzing the problems surrounding mobile phone positioning, they realized the solution was right in front of their eyes—in the network itself. The network has contact with mobile devices in a variety of situations, and with the new method from SICS, the locations can be tracked within the network. The proposed method uses many short traces to map the collective behaviour of network users without storing longer individual trajectories.
The biggest win is that this method makes manual configuration of network parameters unnecessary: with statistics and optimization, it can be done automatically. The demand for this kind of technology is only going to grow, especially with the introduction of more heterogenous networks.
An important and difficult configuration problem
Configuring the mobility management entities (MMEs) that calculate the location of a mobile phone is a resource-intensive task. Cellular networks currently rely on fixed collections of cells – tracking areas – for user equipment localization. Tracking areas are manually configured and maintained; this is therefore an important configuration and resource management problem. The imperfections of the configuration results are particularly apparent for people moving collectively over tracking area borders, for example when a conversation breaks off and the internet connection is lost on a subway.
It was with this background that, a few years ago, Ericsson turned to SICS to work together to develop a better method and a tool to decide how the MMEs should be configured and where the boundaries between these tracking areas should be.
Knowing how people move is essential to determine the best placement for the boundaries. When we considered this, we came to an important realization: the network sees a lot of movements and generates the information necessary to set the parameters itself. A more radical approach would therefore be to dynamically and autonomously reconfigure the tracking areas online and make them local to each cell.
The research project has been successful and has now resulted in a new patent. A completely new mechanism has been designed based on a distributed algorithm to disseminate mobility information between nodes in the network, a local probabilistic model estimated from this data and an optimization mechanism to implement efficient incremental paging in each area.
Taking the solution forward
Ericsson has now taken over the rights to the patent  and Per Kreuger hopes to see the technology up and running soon. Configuring the network is time-consuming and expensive for the operators and need for network solutions like this one is growing in pace with the fact that we’re more connected and we use cellular networks for more task and in new contexts. Our solution shows that configuration efficiency can be improved considerably [2,3], and it’s currently an excellent example of the benefits of Probabilistic Network Management.
Mobility is only one of the areas in which SICS is currently developing Probabilistic Network Management (PNM) approaches. The Probabilistic Network Management paradigm specifies non-deterministic methods in which decisions are based on probabilistic objectives and richer statistical monitoring information, rather than on strict performance guarantees and measurements. Compared to current network management technology, PNM approaches provide new effective means of resource-efficient and flexible network management solutions.
 Å. Arvidsson, D. Gillblad, P. Kreuger: “Tracking user terminals in a mobile communication network”, Patent PCT/EP2011/060090}, June 2011, Ericsson AB
 P. Kreuger, D. Gillblad, Å. Arvidsson: “Zero configuration adaptive paging (zCap)”, IEEE 76th Veh. Technol. Conf., Québec, 3-6 Sept. 2012, 978-1-4673-1881-5, http://www.ieeevtc.org/vtc2012fall/
 P. Kreuger, D. Gillblad, Å. Arvidsson: “zCap: A zero configuration adaptive paging and mobility management mechanism”, Journal of Network Management, forthcoming.
Per Kreuger, SICS Swedish ICT