Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Uplink Performance of Cell-Free Massive MIMO with Multi-Antenna Users
  Over Jointly-Correlated Rayleigh Fading Channels   In this paper, we investigate a cell-free massive MIMO system with both
access points (APs) and user equipments (UEs) equipped with multiple antennas
over jointly-correlated Rayleigh fading channels. We study four uplink
implementations, from fully centralized processing to fully distributed
processing, and derive their achievable spectral efficiency (SE) expressions
with minimum mean-squared error successive interference cancellation (MMSE-SIC)
detectors and arbitrary combining schemes. Furthermore, the global and local
MMSE combining schemes are derived based on full and local channel state
information (CSI) obtained under pilot contamination, which can maximize the
achievable SE for the fully centralized and distributed implementation,
respectively. We study a two-layer decoding implementation with an arbitrary
combining scheme in the first layer and optimal large-scale fading decoding
(LSFD) in the second layer. Besides, we compute novel closed-form SE
expressions for the two-layer decoding implementation with maximum ratio (MR)
combining. In the numerical results, we compare the SE performance for
different implementation levels, combining schemes, and channel models. It is
important to note that increasing the number of antennas per UE may degrade the
SE performance.

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The categories of this paper are: hep-lat
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The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
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The categories of this paper are: q-fin
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The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
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The categories of this paper are: chao-dyn
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph
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The categories of this paper are: math-ph
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The categories of this paper are: cond-mat