Proc. IEEE Int. Global Communications Conf., Nov. 29-Dec. 3, 2004, Dallas, TX, accepted for publication.

Comparison of Space-Time Water-filling and Spatial Water-filling for MIMO Fading Channels

Zukang Shen, Robert W. Heath, Jr., Jeff Andrews, and Brian L. Evans

Wireless Networking and Communications Group, Dept. of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712-1084 USA - - -

Paper - Lecture Slides


In this paper, the capacities achieved by spacetime water-filling and spatial water-filling for MIMO fading channels are compared. Both the effects of fast fading and shadowing are considered. It is found that for Rayleigh fast fading MIMO channels, the spectral efficiency per antenna achieved by one-dimensional spatial water-filling is close to two-dimensional space-time water-filling. However, with log-normal shadowing, space-time water-filling achieves significantly higher capacity per antenna than spatial water-filling at low to moderate SNR regimes. Furthermore, space-time water-filling has lower computational complexity than spatial water-filling. It is also shown that space-time water-filling requires a priori knowledge of the channel gain distribution, and for Rayleigh channels with lognormal shadowing, the spectral efficiency advantage over spatial water-filling comes with an increased channel outage probability.

COPYRIGHT NOTICE: All the documents on this server have been submitted by their authors to scholarly journals or conferences as indicated, for the purpose of non-commercial dissemination of scientific work. The manuscripts are put on-line to facilitate this purpose. These manuscripts are copyrighted by the authors or the journals in which they were published. You may copy a manuscript for scholarly, non-commercial purposes, such as research or instruction, provided that you agree to respect these copyrights.

Last Updated 11/24/04.