4th Workshop on Positioning, Navigation, and Communication 2007 (WPNC '07) workshop proceedings, Leibniz Universilty of Hannover, Hannover, Germany, March 22, 2007 / Thomas Kaiser, Klaus Jobmann, Kyandoghere Kyamakya (eds.). - Kaiser, Thomas, Prof. Dr.-Ing; Jobmann, Klaus; Kyamakya, Kyandoghere (Institute of Electrical and Electronics Engineers, 2007)