Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Unified Framework for the Ergodic Capacity of Spectrum Sharing
  Cognitive Radio Systems   We consider a spectrum sharing communication scenario in which a primary and
a secondary users are communicating, simultaneously, with their respective
destinations using the same frequency carrier. Both optimal power profile and
ergodic capacity are derived for fading channels, under an average transmit
power and an instantaneous interference outage constraints. Unlike previous
studies, we assume that the secondary user has a noisy version of the cross
link and the secondary link Channel State Information (CSI). After deriving the
capacity in this case, we provide an ergodic capacity generalization, through a
unified expression, that encompasses several previously studied spectrum
sharing settings. In addition, we provide an asymptotic capacity analysis at
high and low signal-to-noise ratio (SNR). Numerical results, applied for
independent Rayleigh fading channels, show that at low SNR regime, only the
secondary channel estimation matters with no effect of the cross link on the
capacity; whereas at high SNR regime, the capacity is rather driven by the
cross link CSI. Furthermore, a practical on-off power allocation scheme is
proposed and is shown, through numerical results, to achieve the full capacity
at high and low SNR

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The categories of this paper are: mtrl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: cond-mat
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The categories of this paper are: funct-an
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The categories of this paper are: eess
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: gr-qc
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The categories of this paper are: nlin
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The categories of this paper are: dg-ga
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-lat
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The categories of this paper are: stat
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The categories of this paper are: astro-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: chem-ph