Detailed information about the type, frequency, and ­location of the use of services is essential for both the strategic and technological alignment of a communications network. The data available to operators of mobile networks include both network-related data, collected for network planning, and user data, ­captured primarily for billing reasons.

Your call leaves its tracks behind

Network-related data are captured by so-called performance management systems at a central location and are available for every radio cell. The data normally refer to network elements such as a cell or base station rather than to individual customers. They contain information such as the transmitted voice minutes and the number of dropped connections in a radio cell. This and other information gathered in the network is used at one hand to determine the network quality and on the other hand to ­obtain the utilization of every single radio cell which can be used to plan network capacity. Owing to operational ­requirements, the data are available almost in real time so that malfunctions and quality bottlenecks can be quickly localized and eliminated when necessary.

The spatial resolution of these data is determined by the size of a radio cell and is typically of the order of magnitude of a few hundred meters for macrocells to less than one hundred meters for microcells. The implementation of the so-called “femtocells” – very small, more or less personalized cells analogous to a DSL connection using WiFi in a home – makes it possible to increase the spatial resolution substantially so that the network operator is able to deduce information about the specific behavior of ­individual households with the aid of performance data.

Since the spatial resolution of these data is not adequate for the elimination of all network malfunctions, so-called “drive tests” are conducted. While a vehicle drives along a defined route, one or more mobiles remain continuously connected to the network and record data specific to the service. An exact geo-reference of all of the measured samples is secured via a GPS receiver. Drive tests are especially used for the precise spatial analysis of the end-to-end performance of individual services. In addition, such data are also collected by so-called measurement probes which are permanently installed at strategically important network hubs and continuously record signalling data of the network.