scholarly journals Design and analysis of an OFDM-based orthogonal multilevel code-shifted differential chaos shift keying

2020 ◽  
Vol 20 (3) ◽  
pp. 1369
Author(s):  
Fadhil Sahib Hasan ◽  
Hayder Fadhil Fahad
Keyword(s):  
Fading Channels ◽  
Chaotic Signal ◽  
Data Rate ◽  
High Data Rate ◽  
High Data ◽  
Signal Sets ◽  
Shift Keying ◽  
Analytic Expressions ◽  
Chaos Shift Keying ◽  
Ber Performance

In this paper, a new non-coherent <span class="il">chaos</span>-<span class="il">based</span> communication that combined <span class="il">Orthogonal</span> <span class="il">Multilevel</span> <span class="il">Code</span>-<span class="il">Shifted</span> <span class="il">Differential</span> <span class="il">Chaos</span> <span class="il">Shift</span> <span class="il">Keying</span> with <span class="il">orthogonal</span> frequency division multiplexing named (<span class="il">OFDM</span>-OMCS-DCSK) modulation system. New <span class="il">orthogonal</span> chaotic signal sets are generated by hybrid Gram-Schmidt algorithm <span class="il">and</span> Walsh <span class="il">code</span> function <span class="il">and</span> used it to carry high data rate in the same time slot. The Bandwidth efficiency <span class="il">of</span> the <span class="il">OFDM</span>-OMCS-DCSK system is comparing with conventional system. Also, the BER analytic expressions are derived under (AWGN) <span class="il">and</span> multipath Rayleigh fading channels <span class="il">and</span> comparing with the simulation results. Furthermore, the BER performance is compared with <span class="il">OFDM</span>-DCSK to found that the proposed system has the best BER performance with high data rate feature.

A Novel Multiple-Access Correlation-Delay-Shift-Keying

2017 ◽  
Vol 27 (02) ◽  
pp. 1750025 ◽  
Author(s):  
J. Y. Duan ◽  
G. P. Jiang ◽  
H. Yang
Keyword(s):  
Fading Channels ◽  
Multiple Access ◽  
Additive White Gaussian Noise ◽  
Reference Signal ◽  
Multipath Fading ◽  
Signal Interference ◽  
Shift Keying ◽  
Chaos Shift Keying ◽  
Differential Chaos Shift Keying ◽  
Ber Performance

In Correlation-Delay-Shift-Keying (CDSK), the reference signal and the information-bearing signal are added together during a certain time delay. Because the reference signal is not strictly orthogonal to the information-bearing signal, the cross-correlation between the adjacent chaotic signal (Intra-signal Interference, ISI) will be introduced into the demodulation at the receiver. Therefore, the Bit-Error Ratio (BER) of CDSK is higher than that of Differential-Chaos-Shift-Keying (DCSK). To avoid the ISI component and enhance the BER performance of CDSK in multiuser scenario, Multiple-Access CDSK with No Intra-signal Interference (MA-CDSK-NII) is proposed. By constructing the repeated chaotic generator and applying the Walsh code sequence to modulate the reference signal, in MA-CDSK-NII, the ISI component will be eliminated during the demodulation. Gaussian approximation method is adopted here to obtain the exact performance analysis of MA-CDSK-NII over additive white Gaussian noise (AWGN) channel and Rayleigh multipath fading channels. Results show that, due to no ISI component and lower transmitting power, the BER performance of MA-CDSK-NII can be better than that of multiple-access CDSK and Code-Shifted Differential-Chaos-Shift-Keying (CS-DCSK).

scholarly journals Quaternion Model of Higher-Order Rotating Polarization Wave Modulation for High Data Rate M2M LPWAN Communication

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 383
Author(s):  
Zaid Ahmad ◽  
Shaiful Jahari Hashim ◽  
Fakhrul Zaman Rokhani ◽  
Syed Abul Rahman Al-Haddad ◽  
Aduwati Sali ◽  
...  
Keyword(s):  
High Reliability ◽  
Substantial Improvement ◽  
Higher Order ◽  
Data Rate ◽  
Sensor Nodes ◽  
High Data Rate ◽  
Error Performance ◽  
Polarization Wave ◽  
High Data ◽  
Ber Performance

With growing interest in Industry 4.0, machine-to-machine communication (M2M) will become the key enabler for low-power wide area networks (LPWANs) in connecting machines and sensor nodes distributed across a distance in the industrial environment. The choice of modulation and diversity techniques, and the selection of spectrum (licensed/unlicensed) will impact and influence the requirements of wireless M2M systems. Link reliability is one of the most important requirements for LPWAN deployment in industrial scenarios. Rotating Polarization Wave (RPW) system has been recently proposed as an LPWAN solution for reliable M2M communication in high clutter environment and it deploys BPSK modulation with polarization diversity (PD). This paper proposes a new multi-level Rotating Polarization Phase-Shift Keying (RP-MPSK) modulation to provide high data rate and energy efficiency. A novel quaternion model for RPW system (Q-RPW) is also proposed to reduce the complexity in modeling, simulation, and implementation. Results using Q-RPW model show that RP-MPSK modulation offers a high diversity gain over BPSK with second-order diversity. Bit error rate (BER) performance of RP-MPSK modulation compared against other LPWAN modulation like MPSK, FSK and QAM has shown high reliability and substantial improvement in SNR. To overcome the degradation in error performance caused by the proposed higher-order modulation, sampling rates are recommended based on BER performance. BER performance of RP-MPSK under multipath and interference conditions is also investigated.

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