Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Low-Rank Spatial Channel Estimation for Millimeter Wave Cellular Systems   The tremendous bandwidth available in the millimeter wave (mmW) frequencies
between 30 and 300 GHz have made these bands an attractive candidate for
next-generation cellular systems. However, reliable communication at these
frequencies depends extensively on beamforming with very high-dimensional
antenna arrays. Estimating the channel sufficiently accurately to perform
beamforming can thus be challenging both due to low coherence time and large
number of antennas. Also, the measurements used for channel estimation may need
to be made with analog beamforming where the receiver can "look" in only
direction at a time. This work presents a novel method for estimation of the
receive-side spatial covariance matrix of a channel from a sequence of power
measurements made at different angular directions. The method reduces the
spatial covariance estimation to a matrix completion optimization problem. To
reduce the number of measurements, the optimization can incorporate the
low-rank constraints in the channels that are typical in the mmW setting. The
optimization is convex and fast, iterative methods are presented to solving the
problem. Simulations are presented for both single and multi-path channels
using channel models derived from real measurements in New York City at 28 GHz.

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The categories of this paper are: nlin
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The categories of this paper are: comp-gas
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The categories of this paper are: quant-ph
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The categories of this paper are: q-fin
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The categories of this paper are: stat
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The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
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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: chao-dyn
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The categories of this paper are: q-alg
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The categories of this paper are: econ
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The categories of this paper are: mtrl-th