Code design for non-coherent MIMO-OFDM systems


Helmut Bölcskei and Moritz Borgmann


Allerton Conf. on Communication, Control, and Computing, Monticello, IL, pp. 237-246, Oct. 2002, (invited paper).

[BibTeX, LaTeX, and HTML Reference]


Recently, the use of coherent space-frequency coding in Orthogonal Frequency Division Multiplexing (OFDM)-based frequency-selective multiple-input multiple-output (MIMO) antenna fading channels has been proposed. Acquiring knowledge of the fading coefficients in a MIMO channel is already very challenging in the flat-fading case. In the frequency-selective case, estimating the MIMO channel becomes significantly more difficult due to the presence of multiple paths, which results in an increased number of channel coefficients. In this paper, we address code design for non-coherent frequency-selective MIMO-OFDM fading links, where neither the transmitter nor the receiver knows the channel. We derive the design criteria and quantify the maximum achievable diversity gain. We demonstrate that unlike in the coherent case, non-coherent space-frequency codes designed to achieve full spatial diversity in the flat-fading case can fail completely to exploit not only frequency diversity but also spatial diversity when used in frequency-selective fading environments. Such codes are termed "catastrophic''. Finally, we provide explicit constructions of full-diversity (space and frequency) achieving codes and assess their performance through simulation results.


MIMO, OFDM, space-frequency codes, non-coherent detection, multiple antenna systems, fading channels, channel coding, wireless communications

Download this document:


Copyright Notice: © 2002 H. Bölcskei and M. Borgmann.

This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.