Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Robust Faster-than-Nyquist PDM-mQAM Systems with Tomlinson-Harashima
  Precoding   A training-based channel estimation algorithm is proposed for the
faster-than-Nyquist PDM-mQAM (m = 4, 16, 64) systems with Tomlinson-Harashima
precoding (THP). This is robust to the convergence failure phenomenon suffered
by the existing algorithm, yet remaining format-transparent. Simulation results
show that the proposed algorithm requires a reduced optical signal-to-noise
ratio (OSNR) to achieve a certain bit error rate (BER) in the presence of
first-order polarization mode dispersion and phase noise introduced by the
laser linewidth.

1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci