Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Approximate Maximum Likelihood Time Synchronization Algorithm for
  Zero-padded OFDM in Channels with Impulsive Gaussian Noise   In wireless communication systems, Orthogonal Frequency-Division Multiplexing
(OFDM) includes variants using either a cyclic prefix (CP) or a zero padding
(ZP) as the guard interval to avoid inter-symbol interference. OFDM is ideally
suited to deal with frequency-selective channels and additive white Gaussian
noise (AWGN); however, its performance may be dramatically degraded in the
presence of impulse noise. While the ZP variants of OFDM exhibit lower bit
error rate (BER)and higher energy efficiency compared to their CP
counterparts,they demand strict time synchronization, which is challenging in
the absence of pilot and CP. Moreover, on the contrary to AWGN, impulse noise
severely corrupts data. In this paper, a new low-complexity timing offset (TO)
estimator for ZP-OFDM for practical impulsive-noise environments is proposed,
where relies on the second-other statistics of the multipath fading channel and
noise. Performance comparison with existing TO estimators demonstrates either a
superior performance in terms of lock-in probability or a significantly lower
complexity over a wide range of signal-to-noise ratio (SNR) for various
practical scenarios.

2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
13
The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci