Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Capacity Bounds for Discrete-Time, Amplitude-Constrained, Additive White
  Gaussian Noise Channels   The capacity-achieving input distribution of the discrete-time, additive
white Gaussian noise (AWGN) channel with an amplitude constraint is discrete
and seems difficult to characterize explicitly. A dual capacity expression is
used to derive analytic capacity upper bounds for scalar and vector AWGN
channels. The scalar bound improves on McKellips' bound and is within 0.1 bits
of capacity for all signal-to-noise ratios (SNRs). The two-dimensional bound is
within 0.15 bits of capacity provably up to 4.5 dB, and numerical evidence
suggests a similar gap for all SNRs.

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The categories of this paper are: comp-gas
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The categories of this paper are: eess
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The categories of this paper are: chao-dyn
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The categories of this paper are: bayes-an
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The categories of this paper are: stat
0
The categories of this paper are: hep-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-bio
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The categories of this paper are: quant-ph
3
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: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ex