Low Complexity Semi-blind Bayesian IterativeReceiver for MIMO-OFDM Systems overTime-varying Multi-path Channels
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Graphical Abstract
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Abstract
Based on the Variational Bayes
expectation-maximization (VBEM) algorithm, a low com-
plexity semi-blind Bayesian iterative receiver with joint
signal detection and channel tracking is proposed for
MIMO-OFDM systems over time-varying multi-path chan-
nels. Since the VBEM algorithm provides the distribution
estimation of all parameters, the proposed signal detec-
tion algorithm is di®erent from the conventional ones in
that the evaluation of extrinsic information is improved by
considering channel estimation error in signal detection.
In addition, with the aid of the soft information provided
by the signal detector, the Recursive VBEM (RVBEM)
algorithm is derived to track the time-varying channels.
Due to the high complexity of the RVBEM algorithm, a
Time-frequency combined low complexity recursive VBEM
(TF-LCRVBEM) algorithm is further proposed to reduce
complexity. The analysis results demonstrate that the
TF-LCRVBEM algorithm totally avoids computation of
matrix inversion and obtains linear complexity. Moreover,
the simulation results show that the proposed receiver
outperforms the conventional receiver, and su®er small
performance loss at relatively high Signal-to-noise-ratios
(SNRs), compared with the optimal receiver with perfect
Channel state information (CSI).
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