Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Frequency-domain Compensation Scheme for IQ-Imbalance in OFDM
  Receivers   A pilot pattern across two OFDM symbols with special structure is devised for
channel estimation in OFDM systems with IQ imbalance at receiver. Based on this
pilot pattern, a high-efficiency time-domain (TD) least square (LS) channel
estimator is proposed to significantly suppress channel noise by a factor
N/(L+1) in comparison with the frequency-domain LS one in [1] where N and L+1
are the total number of subcarriers and the length of cyclic prefix,
respectively. Following this, a low-complexity frequency-domain (FD) Gaussian
elimination (GE) equalizer is proposed to eliminate IQ distortion by using only
2N complex multiplications per OFDM symbol. From simulation, the proposed
scheme TD-LS/FD-GE using only two pilot OFDM symbols achieves the same bit
error rate (BER) performance under ideal channel knowledge and no IQ imbalances
at low and medium signal-to-noise ratio (SNR) regions whereas these
compensation schemes including FD-LS/Post-FFT LS, FD-LS/Pre-FFT Corr, and
SPP/Pre-FFT Corr in [1] require about twenty OFDM training symbols to reach the
same performance where A/B denotes compensation scheme with A being channel
estimator and B being equalizer.

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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: patt-sol
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The categories of this paper are: q-bio
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The categories of this paper are: dg-ga
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The categories of this paper are: physics
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The categories of this paper are: gr-qc
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The categories of this paper are: stat
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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: cond-mat
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The categories of this paper are: ao-sci
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The categories of this paper are: quant-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: astro-ph