Broadband vector channel sounder for MIMO channel measurement

3G and 4G mobile communication systems consider multiple antennas at both receiver and transmitter for reaching enhanced channel capacity at well defined quality of service. Perfect design of such systems requires profound knowledge of the radio channel, especially its time-variant characteristics in various radio environments. A precise characterization of the radio channel is given by the vector channel impulse response (VCIR). In multi input multiple output (MIMO) systems the VCIR is measured for each transmitting antenna to a configured RX antenna array. The time variance of the radio channel requires high speed recording of VCIR with respect to the maximum Doppler frequency. The presented vector channel sounder covers all MIMO aspects. Up to 256 MIMO channels can be configured by software. The broadband technique grants high time resolution. Superresolution techniques can be used for joint estimation of time delay, direction of arrival and direction of departure with respect to multipath propagation. The measurement data can be used directly (as stored radio channel) as well as indirectly (as derived channel model) for realistic link- and system-level simulation.