SABA - A testbed for a real-time MIMO system

The growing demand for high data rates for wireless communication systems leads to the development of new technologies to increase the channel capacity thus increasing the data rate. MIMO (multiple-input multiple-output) systems are best qualified for these applications. In this paper, a MIMO test environment for high data rate transmissions in frequency-selective environments is presented. An overview of the testbed is given, including the analyzed algorithms, the digital signal processing with a new highly parallel processor to perform the algorithms in real time, as well as the analog front-ends. A brief overview of the influence of polarization on the channel capacity is given as well. Using this testbed, future transmission schemes for spatial multiplexing and multiuser systems can be tested and evaluated. Due to bidirectional transmission, uplink channel knowledge can be reused for downlink predistortion. Thus, among different transmission schemes, the promising approach of predistortion can be tested under realistic conditions. The testbed is still under development. In the next step, the system will be extended to 2 X 2 bidirectional transmission and after that to a 4 X 4 MIMO system. Furthermore, channel coding algorithms will be implemented.