Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Investigation of Wireless Channel Asymmetry in Indoor Environments   Asymmetry is unquestionably an important characteristic of the wireless
propagation channel, which needs to be accurately modeled for wireless and
mobile communications, 5G networks, and associated applications such as
indoor/outdoor localization. This paper reports on the potential causes of
propagation asymmetry. Practical channel measurements at Khalifa University
premises proved that wireless channels are asymmetric in realistic scenarios.
Some important conclusions and recommendation are also summarized.

20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc