Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: NOMA Channel Estimation and Signal Detection using Rotational Invariant
  Codes and Machine Learning   This paper studies the joint channel estimation and signal detection for the
uplink power domain non-orthogonal multiple access. The proposed technique
performs both detection and estimation without the need of pilot symbols by
using a clustering technique. To remove the effect of channel fading, we apply
rotational invariant coding to assist signal detection at receiver without
sending pilots. We utilize Gaussian mixture model (GMM) to automatically
cluster the received signals without supervision and optimize decision
boundaries to improve the bit error rate (BER) performance.

29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom