Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Closed-Form Hybrid Beamforming Solution for Spectral Efficiency Upper
  Bound Maximization in mmWave MIMO-OFDM Systems   Hybrid beamforming is considered a key enabler to realize millimeter wave
(mmWave) multiple-input multiple-output (MIMO) communications due to its
capability of considerably reducing the number of costly and power-hungry radio
frequency chains in the transceiver. However, in mmWave MIMO orthogonal
frequency-division multiplexing (MIMO-OFDM) systems, hybrid beamforming design
is challenging because the analog precoder and combiner are required to be
shared across the whole employed bandwidth. In this paper, we propose
closed-form solutions to the problem of designing the analog precoder/combiner
in a mmWave MIMO-OFDM system by maximizing the upper bound of the spectral
efficiency. The closed-form solutions facilitate the design of analog
beamformers while guaranteeing state-of-art performance. Numerical results show
that the proposed algorithm attains a slightly improved performance with much
lower computational complexity compared to the considered benchmarks.

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: q-alg
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
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The categories of this paper are: dg-ga
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The categories of this paper are: stat
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The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
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The categories of this paper are: q-fin
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The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg