The Vienna MIMO Testbed
The Vienna MIMO testbed is a custom built wireless testbed that allows for repeatable and fully controllable over-the-air experiments. Thereby, the testbed is not restricted to a certain wireless communication standard. It allows for experiments with arbitrary signals with a bandwidth of up to 20 MHz.
The major components are:
Three outdoor transmitters supporting up to four antennas each are located on three different rooftop locations. There, the digital signal samples are converted with a precision of 16 bits and are transmitted with adjustable power within a range of about -35 dBm to 35 dBm per antenna.
One indoor receiver with four channels that converts the received signals with a precision of 16 bits before the raw signal samples are saved to hard disk. The receive antennas are mounted on a positioning table, which allows for measurements at different positions within an area of about 1 m x 1 m, correspondingly 8 λ x 8 λ.
Accurate time and frequency synchronization of all stations is implemented by using GPS synchronized rubidium frequency standards at all stations. Thereby, a dedicated control and synchronization network is used to exchange timing and synchronization information.
Setup to measure at high velocities
At the receiver side, a custom built rotary unit extends the capabilities of the Vienna MIMO testbed for fully controllable wireless measurements at user velocities of up to 400 km/h. Thereby, repeatable time-variant channels are generated by rotating the receive antennas around a central pivot. A light barrier generates a trigger every time the receive antennas pass. This allows for repeated transmissions over the same time-varying channel and therefore for a fair comparison of different transmit signals at different velocities. In order to generate different channel realizations the whole setup can be moved within an area of 3 λ x 2.2 λ.
- Martin Lerch, Sebastian Caban, Martin Mayer, Markus Rupp:
The Vienna MIMO Testbed: Evaluation of Future Mobile Communication Techniques
Intel Technology Journal, 4G Wireless Communications: Real World Aspects and Tools (2014)
- Martin Lerch, Markus Rupp:
Measurement-Based Evaluation of the LTE MIMO Downlink at Different Antenna Configurations
17th International ITG Workshop on Smart Antennas (2013)
- Martin Mayer et al.:
Measurement Based Evaluation of Interference Alignment on the Vienna MIMO Testbed
10th International Symposium on Wireless Communication Systems (2013)
- Sebastian Caban, Ronald Nissel, Martin Lerch, Markus Rupp:
Controlled OFDM Measurements at Extreme Velocities
6th Extreme Conference on Communication and Computing (2014)
- José Rodríguez-Piñeiro et al.:
Experimental Assessment of 5G-Candidate Modulation Schemes at Extreme Speeds
IEEE Sensor Array and Multichannel Signal Processing Workshop (2016)