Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cooperative Ambient Backscatter Communications for Green
  Internet-of-Things   Ambient backscatter communication (AmBC) enables a passive backscatter device
to transmit information to a reader using ambient RF signals, and has emerged
as a promising solution to green Internet-of-Things (IoT). Conventional AmBC
receivers are interested in recovering the information from the ambient
backscatter device (A-BD) only. In this paper, we propose a cooperative AmBC
(CABC) system in which the reader recovers information not only from the A-BD,
but also from the RF source. We first establish the system model for the CABC
system from spread spectrum and spectrum sharing perspectives. Then, for flat
fading channels, we derive the optimal maximum-likelihood (ML) detector,
suboptimal linear detectors as well as successive interference-cancellation
(SIC) based detectors. For frequency-selective fading channels, the system
model for the CABC system over ambient orthogonal frequency division
multiplexing (OFDM) carriers is proposed, upon which a low-complexity optimal
ML detector is derived. For both kinds of channels, the bit-error-rate (BER)
expressions for the proposed detectors are derived in closed forms. Finally,
extensive numerical results have shown that, when the A-BD signal and the
RF-source signal have equal symbol period, the proposed SIC-based detectors can
achieve near-ML detection performance for typical application scenarios, and
when the A-BD symbol period is longer than the RF-source symbol period, the
existence of backscattered signal in the CABC system can enhance the ML
detection performance of the RF-source signal, thanks to the beneficial effect
of the backscatter link when the A-BD transmits at a lower rate than the RF
source.

30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol