Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: How Often Should CSI be Updated for Massive MIMO Systems with Massive
  Connectivity?   Massive multiple-input multiple-output (MIMO) systems need to support massive
connectivity for the application of the Internet of things (IoT). The overhead
of channel state information (CSI) acquisition becomes a bottleneck in the
system performance due to the increasing number of users. An intermittent
estimation scheme is proposed to ease the burden of channel estimation and
maximize the sum capacity. In the scheme, we exploit the temporal correlation
of MIMO channels and analyze the influence of the age of CSI on the downlink
transmission rate using linear precoders. We show the CSI updating interval
should follow a quasi-periodic distribution and reach a trade-off between the
accuracy of CSI estimation and the overhead of CSI acquisition by optimizing
the CSI updating frequency of each user. Numerical results show that the
proposed intermittent scheme provides significant capacity gains over the
conventional continuous estimation scheme.

20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ