Towards a 4×4 MIMO testbed

One of the most promising key technologies in wireless communications are multi-antenna techniques. Even if there is no doubt on this in the scientific community, no significant multi-antenna based products seems to be available on the market yet. A close conjecture is the lack of efficient and low cost implementation. In fact, the development of simple MIMO algorithms being capable for deployment in multi-user environments is a demanding challenge. If, in addition, a feedback from the receiver to the transmitter should be implemented as well to further exploit the given wireless channel, an extremely flexible real-time testbed is required to demonstrate the progress from advances in theory towards realistic wireless systems. Our proposed hardware platform is able to validate the usefulness of multi-user multi-antenna techniques in real-time with and without feedback of channel state information and serves therefore as an ideal tool for the design of future wireless communication systems.