Finally, we mention another emerging application area of great potential: telecommunications. An example of a real-world communications application where blind separation techniques are useful is the separation of the user's own signal from the interfering other users' signals in CDMA (Code-Division Multiple Access) mobile communications [39]. This problem is semi-blind in the sense that certain additional prior information is available on the CDMA data model. But the number of parameters to be estimated is often so high that suitable blind source separation techniques taking into account the available prior knowledge provide a clear performance improvement over more traditional estimation techniques [39].