Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hybrid Mechanical and Electronic Beam Steering for Maximizing OAM
  Channel Capacity   Radio frequency-orbital angular momentum (RF-OAM) is a novel approach of
multiplexing a set of orthogonal modes on the same frequency channel to achieve
high spectrum efficiencies. Since OAM requires precise alignment of the
transmit and the receive antennas, the electronic beam steering approach has
been proposed for the uniform circular array (UCA)-based OAM communication
system to circumvent large performance degradation induced by small antenna
misalignment in practical environment. However, in the case of large-angle
misalignment, the OAM channel capacity can not be effectively compensated only
by the electronic beam steering. To solve this problem, we propose a hybrid
mechanical and electronic beam steering scheme, in which mechanical rotating
devices controlled by pulse width modulation (PWM) signals as the execution
unit are utilized to eliminate the large misalignment angle, while electronic
beam steering is in charge of the remaining small misalignment angle caused by
perturbations. Furthermore, due to the interferometry, the receive
signal-to-noise ratios (SNRs) are not uniform at the elements of the receive
UCA. Therefore, a rotatable UCA structure is proposed for the OAM receiver to
maximize the channel capacity, in which the simulated annealing algorithm is
adopted to obtain the optimal rotation angle at first, then the servo system
performs mechanical rotation, at last the electronic beam steering is adjusted
accordingly. Both mathematical analysis and simulation results validate that
the proposed hybrid mechanical and electronic beam steering scheme can
effectively eliminate the effect of diverse misalignment errors of any
practical OAM channel and maximize the OAM channel capacity.

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The categories of this paper are: hep-th
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: cond-mat
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The categories of this paper are: gr-qc
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The categories of this paper are: bayes-an
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: patt-sol
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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: nucl-th
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The categories of this paper are: physics