scholarly journals FPGA implementation of LDPC soft-decision decoders based DCSK for spread spectrum applications

2021 ◽  
Vol 11 (6) ◽  
pp. 4794
Author(s):  
Fadhil S. Hasan ◽  
Mahmood F. Mosleh ◽  
Aya H. Abdulhameed
Keyword(s):  
Spread Spectrum ◽  
Simple Structure ◽  
Soft Decision ◽  
Soft Data ◽  
Resource Requirement ◽  
Decoding Algorithms ◽  
Ldpc Decoding ◽  
Shift Keying ◽  
Chaos Shift Keying ◽  
Log Domain

<span lang="EN-US">Spread spectrum (SS) communications have attracted interest because of their channel attenuation immunity and low intercept potential. Apart from some extra features such as basic transceiver structures, chaotic communication would be the analog alternative to digital SS systems. Differential chaos shift keying (DCSK) systems, non-periodic and random characteristics among chaos carriers as well as their interaction with soft data are designed based on low-density parity-check (LDPC) codes in this brief. Because of simple structure, and glorious ability to <span>correct errors. Using the Xilinx kintex7 FPGA development kit, we investigate the hardware performance and resource requirement tendencies of the DCSK</span> communication system based on LDPC decoding algorithms (Prob. Domain, Log Domain and Min-Sum) over AWGN channel. The results indicate that the proposed system model has substantial improvements in the performance of the bit error rate (BER) and the real-time process. The Min-Sum decoder has relatively fewer FPGA resources than the other decoders. The implemented system will achieve 10-4 BER efficiency with 5 dB associate E<sub>b</sub>/N<sub>o</sub> as a coding gain.</span>

Design of Modified Minsum Decoder of LDPC Code in the Simplified Difference-Domain

2013 ◽  
Vol 385-386 ◽  
pp. 1576-1581
Author(s):  
Zhong Xun Wang ◽  
Xing Long Gao
Keyword(s):  
Belief Propagation ◽  
Additive White Gaussian Noise ◽  
Ldpc Code ◽  
Phase Shift Keying ◽  
Computation Complexity ◽  
Decoding Algorithm ◽  
Ldpc Decoding ◽  
Shift Keying ◽  
Log Domain ◽  
Binary Phase Shift Keying

In this paper, we propose the modified minsum decoding algorithm of LDPC(Low-Density Parity-Check) code in the simplified difference-domain on the basis of detailed analysis of LDPC decoding algorithm in difference-domain. The simulation indicates that the proposed decoding algorithm offers almost no performance degradation compared with the BP(Belief Propagation) decoding algorithm in log-domain and the decoding algorithm in difference-domain and offers better performance than minsum decoding algorithm in log-domain and greatly reduces the computation complexity in AWGN(Additive White Gaussian Noise) channel and under BPSK(Binary Phase Shift Keying) modulation.

Quadrature MC-DCSK Scheme for Chaos-Based Cognitive Radio

2019 ◽  
Vol 29 (13) ◽  
pp. 1950177 ◽  
Author(s):  
Nguyen Xuan Quyen
Keyword(s):  
Cognitive Radio ◽  
Spread Spectrum ◽  
Original Data ◽  
Wireless Channel ◽  
Multicarrier Modulation ◽  
Quadrature Modulation ◽  
Bandwidth Efficiency ◽  
Spreading Sequence ◽  
Shift Keying ◽  
Chaos Shift Keying

In this study, we investigate an enhanced architecture of multicarrier differential chaos-shift keying (MC-DCSK) scheme using quadrature modulation (QM), namely QMC-DCSK. The use of quadrature modulation aims at doubling the data rate over a defined bandwidth and hence improve bandwidth efficiency of the system. In the proposed scheme, the chaotic spreading sequence is transmitted on a predefined frequency while each of the remaining frequencies is phase-shifted at a [Formula: see text] angle in order to produce two quadrature subcarriers located at the same frequency. These subcarriers are modulated by the product of the chaotic spreading sequence and the corresponding bit substreams in parallel. Noncoherent demodulation is carried out in the receiver in order to recover the original data based on the sign of correlation values. Architecture and operation of the conventional and proposed schemes are described. The BER performance over a wireless channel is theoretically derived and then numerically verified. The bit rate, energy and bandwidth efficiencies are evaluated in comparison with those of MC-DCSK. In particular, the application of the proposed scheme to cognitive radio (CR) in the scenario of using multicarrier modulation and chaotic spread-spectrum is discussed and evaluated. The obtained results prove that QMC-DCSK is a fit technique for CR communications.

scholarly journals Signal Properties under Multi-Carrier Chaos–Shift Keying

2021 ◽  
Vol 1804 (1) ◽  
pp. 012088
Author(s):  
Salsabeel S. Hasan ◽  
Zahir M. Hussain
Keyword(s):  
Shift Keying ◽  
Chaos Shift Keying

scholarly journals Design and Implementation of a Chaotic Scheme in Additive White Gaussian Noise Channel

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Nizar Al Bassam ◽  
Oday Jerew
Keyword(s):  
Bit Error Rate ◽  
Gaussian Noise ◽  
Chaotic Systems ◽  
Gaussian Approximation ◽  
Additive White Gaussian Noise ◽  
Design And Implementation ◽  
Shift Keying ◽  
Transmitted Signal ◽  
Chaos Shift Keying ◽  
Channel Environment

A new chaotic scheme named Flipped Chaotic On-Off Keying (FCOOK) is proposed for binary transmission. In FCOOK, the low correlation value between the stationary signal and its mirrored version is utilized. Transmitted signal for binary 1 is a chaotic segment added to its time flipped (mirrored) version within one bit duration, while in binary 0, no transmission takes place within the same bit duration. The proposed scheme is compared with the standard chaotic systems: Differential Chaos Shift Keying (DCSK) and Correlation Delay Shift Keying (CDSK). The Bit Error Rate (BER) of FCOOK is studied analytically based on Gaussian approximation method. Results show that the BER performance of FCOOK outperforms DCSK and CDSK in AWGN channel environment and with variousEb/Nolevels. Additionally, FCOOK offers a double bit rate compared with the standard DCSK.

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