Adaptive Time-Frequency Spreading of Quasi-Orthogonal Block Codes for MIMO-OFDM Systems

J. Ong, A. S. Jayalath, C. N. Athaudage
<span title="">2006</span> <i title="IEEE"> 2006 10th IEEE Singapore International Conference on Communication Systems </i> &nbsp;
This paper describes a novel low complexity time-frequency spreading of orthogonal block codes for MIMO-OFDM systems in highly time and frequency selective channels. The space-time codes (STC) and space-frequency codes (SFC) proposed in literature for MIMO-OFDM systems require a quasi-static channel, where the channel is assumed to be constant over a number of OFDM time symbols or OFDM subcarriers. In orthogonal block codes (OBC) this is equal to the number of transmit antennas N t employed.
more &raquo; ... higher order space-diversity systems with N t ≥ 4, it is likely that the assumption of constant channel within the OBC to be violated in fast fading channels resulting performance degradation. We propose an adaptive time-frequency spreading strategy that minimizes the decoding error rate in different types of fading channels. The adaptation technique incorporated is based on a fading interference matric, which is evaluated at the transmitter using channel fading statistics. Simulation results demonstrate the effectiveness of the proposed adaptive time-frequency spreading of OBCs.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="">doi:10.1109/iccs.2006.301391</a> <a target="_blank" rel="external noopener" href="">fatcat:5slrjwyttrebxftopcr5h7s2dy</a> </span>
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