Mobile propagation measurements using a digital channel sounder with a bandwidth matched to the GSM-system

The Forschungsinstitut der Deutsche Bundespost Telekom has constructed, in cooperation with the Lehrstuhl fur Nachrichtentechnik der Universitat Erlangen, Germany, a channel sounder to measure the time-variant impulse responses (IRs) of the mobile radio channel. Its bandwidth is matched to the GSM digital mobile radio system. The channel sounder is based on correlation of pseudo-noise sequences (PNS) using digital signal processing which allows a minimum repetition time of 23 ms for the determination and storage of subsequent complex IRs. The maximum excess delay to be determined is 127 μs. Careful calibration has been performed to achieve high accuracy of the radio path loss and the other parameters characterising the IRs. These parameters are processed off-line using adaptive noise suppression. Propagation measurements showed that large excess delays occur not only in hilly terrain but also in industrialised areas where large buildings are located