Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Millimeter-Wave Communication with Non-Orthogonal Multiple Access for 5G   To further improve the system capacity for 5G, we explore the integration of
non-orthogonal multiple access (NOMA) in mmWave communications (mmWave-NOMA)
for future 5G systems. Compared with the conventional NOMA, the distinguishing
feature of mmWave-NOMA is that, it is usually characterized by transmit/receive
beamforming with large antenna arrays. In this paper, we focus on the design
challenges of mmWave-NOMA due to beamforming. Firstly, we study how beamforming
affects the sum-rate performance of mmWave-NOMA, and find that with
conventional single-beam forming, the performance may be offset by the relative
angle between NOMA users. Then, we consider multi-beam forming for mmWave-NOMA,
which is shown to be able to achieve promising performance enhancement as well
as robustness. We further investigate the challenging joint design of the
intertwined power allocation and user pairing for mmWave-NOMA. We also discuss
the challenges and propose some potential solutions in detail. Finally, we
consider hybrid spatial division multiple access (SDMA) and NOMA in mmWave
communications, where some possible system configurations and the corresponding
solutions are discussed to address the multi-user issues including multi-user
precoding and multi-user interference (MUI) mitigation.

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The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
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The categories of this paper are: hep-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: comp-gas
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The categories of this paper are: q-bio
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The categories of this paper are: econ
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The categories of this paper are: q-fin
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The categories of this paper are: funct-an
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The categories of this paper are: adap-org
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The categories of this paper are: bayes-an
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The categories of this paper are: chem-ph
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The categories of this paper are: q-alg
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The categories of this paper are: cmp-lg