"Multiple-input multiple-output (MIMO) wireless communication systems have attracted a lot of interest in the past decade due to their capability in delivering high spectral efficiency as well as their robust performance against fading. In MIMO inter-symbol interference (lSI) channels, a severe interference problem occurs due to the lSI and co-channel interference. Thus, the error propagation problem becomes more serious, and its mitigation has to be considered when designing the receiver. In this regard, a turbo equalizer which exchanges soft information between the equalizer and the decoder has been shown to be an effective method to combat the lSI caused by frequency-selective channels. By iteratively exchanging soft extrinsic information between a soft-input soft-output equalizer and a decoder, turbo equalizer can achieve large performance gains over a separated equalizer and decoder structure. In its original form, Douillard employed maximum a posteriori probability (MAP) equalization and decoding methods in an iterative fashion. However, the computational complexity required to derive the a posteriori log likelihood ratio (LLR) for the MAP decoder is prohibitive. Therefore, the design of low-complexity turbo equalizers based on minimum mean square error (MMSE) criterion has attracted considerable attention in the past few years. In this work, a new soft decision feedback equalizer (SDFE) is proposed for MIMO Communication systems. The computational complexity of the proposed algorithm only linearly grows with the number of equalizer coefficients, compared with the quadratic complexity of minimum mean square error (MMSE)-based linear turbo equalizer with time-varying coefficients. The performance of our proposed algorithm is tested by extensive undersea trial data collected in two medium-range undersea experiments"--Abstract, page iv.
Zheng, Y. Rosa
Grant, Steven L.
Moss, Randy Hays, 1953-
Liu, Xiaoqing Frank
Electrical and Computer Engineering
Ph. D. in Electrical Engineering
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- Low complexity soft-decision feedback turbo equalization for MIMO systems with multilevel modulations
- Soft-decision feedback turbo equalization for LDPC-coded MIMO underwater acoustic communications
- Soft feedback turbo equalization for underwater acoustic communications
- Turbo equalization using reduced state map algorithm
xi, 101 pages
© 2012 Amirhossein Rafati, All rights reserved.
Dissertation - Restricted Access
MIMO systems -- Design
Feedback control systems -- Design
Equalizers (Electronics) -- Mathematical models
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Electronic access to the full-text of this document is restricted to Missouri S&T users. Otherwise, request this publication directly from Missouri S&T Library or contact your local library.http://merlin.lib.umsystem.edu:80/record=b9660402~S5
Rafati, Amirhossein, "Design and experimental study of turbo equalization for multiple antenna systems" (2012). Doctoral Dissertations. 17.
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