Instantaneous Signal and Self-Interference Power of MIMO Eigenmode Transmission with Feedback Time Delay

Singular Value Decomposition (SVD) techniques are well-known for providing an elegant transceiver architecture, that can realize the intrinsic spatial links of a MIMO channel. Such a scheme is also referred to as eigen-beamforming or eigenmode transmission. The system performance is, however, closely related to the quality of the channel information at both ends of the link. Hence, we focus on the effect of feedback time delay, which causes the transmitter to use outdated channel information in timevarying fading channels. In this paper, we derive an analytical expression for the instantaneous SINR of eigenmode transmission with a feedback time delay T. Furthermore, this expression implies a novel metric that gauges the system performance sensitivity to time-variations of the steering vectors (eigenvectors of the channel correlation matrix) at the transmitter.