Performance analysis of a channel oriented concept for multi-user MIMO downlinks with frequency selective channels

Recently, receiver oriented transmission schemes have been proposed for multi-user MIMO (multiple input multiple output) mobile radio downlinks. In such systems, the receiver algorithms are a priori chosen and the transmitter algorithms are a posteriori adapted under consideration of channel information and the receiver algorithms. This leads to the advantage of particularly simple receivers. A certain drawback of such schemes consists in a slight transmit energy increase as compared to conventional transmitter oriented systems. In order to overcome this drawback, in this paper a beneficial choice of the receiver algorithms based on space-time eigen-signatures is proposed for the receiver oriented transmission scheme joint transmission (JT). In this approach, not only the transmitter, but also the receivers exploit channel information, which leads to a channel oriented multi-user MIMO downlink. The analysis shows that the system performance strongly depends on the cross-correlation coefficients of the space-time eigen-signatures. Consequently, dependencies of these coefficients on the system performance are studied intensively. Analytical and numerical results show that the presented channel oriented multi-user MIMO downlink system performs near optimum with respect to the efficient use of the radiated transmit energy.