Conference Paper

An Iterative Decoding Technique for Cooperative STBC-OFDM Systems with Multiple Carrier Frequency Offsets

DOI: 10.1109/PIMRC.2007.4394476 Conference: Personal, Indoor and Mobile Radio Communications, 2007. PIMRC 2007. IEEE 18th International Symposium on
Source: IEEE Xplore

ABSTRACT

In this paper, an iterative decoding technique for cooperative space-time block coded orthogonal frequency division multiplexing (STBC-OFDM) systems is proposed to mitigate the intercarrier interference (ICI) caused by multiple carrier frequency offsets (CFOs) in cooperative transmission. The proposed iterative decoding technique is shown to mitigate the noise enhancement effect on the STBC-OFDM signals caused by multiple CFOs, and be effective in reducing ICI especially when the system has a large FFT size and a large multiple CFOs.

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    • "However, this approach suffers from performance loss in the high SNR region. In order to remove the error floor, an iterative decoding technique was proposed in [13], where the ICI terms in the channel matrix are gradually eliminated by iterations at the cost of increased complexity. In [14], time domain equalization using the Viterbi algorithm was proposed. "

    Preview · Article · Jan 2012 · KSII Transactions on Internet and Information Systems
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    ABSTRACT: This paper addresses the problem of interference mitigation in cooperative Space Time Block Coded Orthogonal Frequency Division Multiplexing (STBC-OFDM) systems in the presence of asynchronism. This scheme first preprocesses the received ST codewords to convert the equivalent fading matrix into a suboptimal ordering upper triangular form based on low complexity permutation QR decomposition, and then suppresses the InterCarrier Interference (ICI) and InterSymbol Interference (ISI) by exploiting Successive Interference Cancellation (SIC) technique. Simulation results show that the performance of the proposed algorithm slightly outmatches or asymptotically approaches to that of the existing Minimum Mean Square Error (MMSE) detector depending on the magnitude of the Carrier Frequency Offsets (CFOs) but with less complexity. Key wordsAsynchronism–Cooperative communication–Orthogonal Frequency Division Multiplexing (OFDM)–QR decomposition–Space Time Block Coding (STBC)
    No preview · Article · Jul 2011 · Journal of Electronics (China)
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    ABSTRACT: In this paper, we propose a multiple CFOs(Carrier Frequency Offset) estimation and mitigation algorithm for the destination node in a cooperative OFDM(Orthogonal Frequency Division Multiplex) system. In a cooperative OFDM system, every relay node has a separate local oscillator, so that each relay-to-destination link has individual CFO parameter, so that the traditional estimation and mitigation algorithms are no longer applicable. In the proposed algorithm, based on the specially designed training sequences, the destination node can decouple the signal from different relay nodes by correlation and simplify the MD(Multi-Dimensional) nonlinear problem to an ID linear problem. Then, an mitigation matrix can be constructed, and the ICI(Inter-Carrier-Interference) caused by multiple CFOs can be perfectly compensated based on the over sampled OFDM symbol vectors. Theoretical analysis and simulation results prove that the proposed algorithm is effective in estimating the multiple CFOs and mitigating the performance degradation.
    No preview · Conference Paper · Nov 2008
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