Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Real-time 10,000 km Straight-line Transmission using a Software-defined
  GPU-Based Receiver   Real-time 10,000 km transmission over a straight-line link is achieved using
a software-defined multi-modulation format receiver implemented on a commercial
off-the-shelf general-purpose graphics processing unit (GPU). Minimum phase 1
GBaud 4-ary quadrature amplitude modulation (QAM) signals are transmitted over
10,000 km and successfully received after detection with a Kramers-Kronig (KK)
coherent receiver. 8-, 16-, 32-, and 64-QAM are successfully transmitted over
7600, 5600, 3600, and 1600 km, respectively.

3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph