Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Framework for Transceiver Designs for Multi-Hop Communications with
  Covariance Shaping Constraints   For multiple-input multiple-output (MIMO) transceiver designs, sum power
constraint is an elegant and ideal model. When various practical limitations
are taken into account e.g., peak power constraints, per-antenna power
constraints, etc., covariance shaping constraints will act as an effective and
reasonable model. In this paper, we develop a framework for transceiver designs
for multi-hop communications under covariance shaping constraints.
Particularly, we focus on multi-hop amplify-and-forward (AF) MIMO relaying
communications which are recognized as a key enabling technology for
device-to-device (D2D) communications for next generation wireless systems such
as 5G. The proposed framework includes a broad range of various linear and
nonlinear transceiver designs as its special cases. It reveals an interesting
fact that the relaying operation in each hop can be understood as a matrix
version weighting operation. Furthermore, the nonlinear operations of
Tomolision-Harashima Precoding (THP) and Decision Feedback Equalizer (DFE) also
belong to the category of this kind of matrix version weighting operation.
Furthermore, for both the cases with only pure shaping constraints or joint
power constraints, the closed-form optimal solutions have been derived. At the
end of this paper, the performance of the various designs is assessed by
simulations.

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The categories of this paper are: mtrl-th
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The categories of this paper are: stat
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The categories of this paper are: hep-ph
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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: patt-sol
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The categories of this paper are: chem-ph
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The categories of this paper are: nlin
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The categories of this paper are: alg-geom
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The categories of this paper are: acc-phys
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
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The categories of this paper are: astro-ph
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The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-lat