RSSI - Received Signal Strength Indication

Fraunhofer IIS's self-contained Positioning Technology for Cities and Buildings

awiloc® Fairs

Visitors to trade fairs often struggle to keep an overview. In the projects run by Fraunhofer IIS, visitors can put together their own personalized list of exhibitors and be guided directly to the booths they selected.

Wireless LAN positioning in a trade show environment poses particular challenges. Vast, open halls, huge crowds and booths set up differently for each event mean that the signal processing algorithm needs to cope with highly variable signal strength levels. Moreover, the software must be usable on a variety of mobile devices with considerably different measurement characteristics.

Four to eight wireless LAN access points, owned by the show organizer, are installed in each hall. To include all relevant variables, several calculation methods were combined, taking the specific environment into account. A special algorithm was developed that focuses on the relative strengths of the signals received from individual wireless LAN access points at any one time rather than on absolute levels, determining e.g. whether a stronger signal is being received from station 1 or station 2. This reduces the influence of the measurement characteristics of mobile devices on positioning accuracy.



We have long experience with the development of trade show guides. During embedded world 2004 the "Trade Show Guide" of the Fraunhofer IIS got the "Embedded Award" for innovative products and services.


Future Work

While the positioning algorithm was developed for trade show settings, it can obviously be used in any similarly open environment such as an airport or railway station.