Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Relay Assisted OFDM with Subcarrier Number Modulation in Multi-Hop
  Cooperative Networks   Orthogonal frequency-division multiplexing (OFDM) with subcarrier number
modulation (OFDM-SNM) manifests its superior nature of high spectral efficiency
(SE) and low complexity for signal estimation. To exploit the spatial gain of
OFDM-SNM, we propose a relay assisted OFDM-SNM scheme for multi-hop cooperative
systems in this letter. It is stipulated that a relay operated by
decode-and-forward (DF) and half-duplex (HD) protocols exists in each hop. We
analyze the outage performance of the relay assisted OFDM-SNM system. The
average outage probability is approximated in closed form. Moreover, to reveal
the diversity and coding gains of relay assisted OFDM-SNM, we explore the
asymptotic outage performance at high signal-to-noise ratio (SNR) by power
series expansion. To verify the improvement on outage performance and energy
efficiency, we carry out the comparison among different multi-hops systems with
traditional OFDM-SNM fixing a certain distance from source to destination.
Simulation results corroborate the derived outage probabilities and provide
insight into the proposed system in this letter.

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The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
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The categories of this paper are: chem-ph
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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat
2
The categories of this paper are: math
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga