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

Ong, Julynn, Jayalath, Dhammika, & Athaudage, Chandranath R. N. (2006) Adaptive Time-Frequency Spreading of Quasi-Orthogonal Block Codes for MIMO-OFDM Systems. In 10th IEEE Singapore International Conference on Communication systems, 2006 (ICCS 2006), Oct. 2006, Singapore.

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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 Nt employed. For higher order space-diversity systems with Ntges4, 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.

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ID Code: 13766
Item Type: Conference Paper
Refereed: Yes
DOI: 10.1109/ICCS.2006.301391
ISBN: 1424404118
Subjects: Australian and New Zealand Standard Research Classification > TECHNOLOGY (100000) > COMMUNICATIONS TECHNOLOGIES (100500) > Communications Technologies not elsewhere classified (100599)
Divisions: Past > QUT Faculties & Divisions > Faculty of Built Environment and Engineering
Copyright Owner: Copyright 2006 IEEE
Copyright Statement: Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Deposited On: 16 Jun 2008 00:00
Last Modified: 29 Feb 2012 14:02

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