Publications in Scientific Journals:

S. Schwarz, M. Rupp:
"Subspace Quantization Based Combining for Limited Feedback Block-Diagonalization";
IEEE Transactions on Wireless Communications, 12 (2013), 11; 5868 - 5879.

English abstract:
Spatial multiplexing of multiple users in a multiantenna
broadcast system, i.e., multi-user MIMO, is a promising
technique for improving the spectral efficiency of cellular networks.
Still, practical implementations struggle with the difficulty
of obtaining sufficiently accurate channel state information at the
transmitter (CSIT), due to restrictions on the capacity of the CSI
feedback links from the users. Without accurate CSIT, residual
multi-user interference diminishes the potential performance
gain of multi-user MIMO, challenging its value for practical
realizations. In this work we show that the CSI feedback overhead
can be significantly reduced if the number of spatially multiplexed
data streams per user is less than the number of receive antennas,
and the antenna outputs are appropriately combined. We
propose an interference-unaware antenna combining algorithm
that minimizes the CSI quantization error, which has the effect of
minimizing multi-user interference at the price of reducing the received
signal power. We mathematically analyze the performance
of the proposed algorithm, substantiating its value for limited
feedback systems. Numerical simulations confirm the potential of
the proposed algorithm in comparison to a traditional technique
that maximizes the received signal power.

limited feedback, quantized feedback, multi-user MIMO, block-diagonalization, antenna combining

"Official" electronic version of the publication (accessed through its Digital Object Identifier - DOI)

Created from the Publication Database of the Vienna University of Technology.