To increase ubiquitous and mobile network access and data rates, scientific and technological development is more and more focussing on the integration of radio access networks (RANs). For an efficient usage of RANs, knowledge of the position of mobile terminals (MTs) is valuable information in order to allocate resources or predict the allocation within a heterogeneous RAN infrastructure.The main objective of WHERE is to combine wireless communications and navigation for the benefit of the ubiquitous access for a future mobile radio system. The impact will be manifold, such as real time localization knowledge in B3G/4G systems that allow them to increase efficiency. Satellite navigation systems will be supplemented with techniques that improve accuracy and availability of position information.The WHERE project addresses the combination of positioning and communication in order to exploit synergies and to improve the efficiency of future wireless communication systems.Thus, the estimation of the position of MTs based on different RANs is the main goal in WHERE. Positioning algorithms and algorithms for combining several positioning measurements allow to estimate the position of MTs. Appropriate definitions of scenarios and system parameters together with channel propagation measurements and derived models will allow to assess the performance of RAN based positioning. Based on the performance of RAN positioning, location based strategies and protocols will be developed in order to optimise as well as to cross-optimise different OSI layers of communication systems and RAT selection policies. Performance assessment of the algorithms is provided by theoretical studies and simulations. Hardware signal processing will provide a verification of the performance of dedicated algorithms under realistic conditions. All the tasks are covered by different work packages, which are in close interaction to ensure an integral research of positioning and communications.