Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Time Varying Channel Tracking with Spatial and Temporal BEM for Massive
  MIMO Systems   In this paper, we propose a channel tracking method for massive multi-input
and multi-output systems under both time-varying and spatial-varying
circumstance. Exploiting the characteristics of massive antenna array, a
spatial-temporal basis expansion model is designed to reduce the effective
dimensions of up-link and down-link channel, which decomposes channel state
information into the time-varying spatial information and gain information. We
firstly model the users movements as a one-order unknown Markov process, which
is blindly learned by the expectation and maximization (EM) approach. Then, the
up-link time varying spatial information can be blindly tracked by Taylor
series expansion of the steering vector, while the rest up-link channel gain
information can be trained by only a few pilot symbols. Due to angle
reciprocity (spatial reciprocity), the spatial information of the down-link
channel can be immediately obtained from the up-link counterpart, which greatly
reduces the complexity of down-link channel tracking. Various numerical results
are provided to demonstrate the effectiveness of the proposed method.

5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
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The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-th
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The categories of this paper are: solv-int