Multi-User Multi-Carrier Differential Chaos Shift Keying Communication System

In this paper, a multi user Multi-Carrier Differential Chaos Shift Keying (MC-DCSK) modulation is presented. The system endeavors to provide a good trade-off between robustness, energy efficiency and high data rate, while still being simple. In this architecture of MC-DCSK system, for each user, chaotic reference sequence is transmitted over a predefined subcarrier frequency. Multiple modulated data streams are transmitted over the remaining subcarriers allocated for each user. This transmitter structure saves energy and increases the spectral efficiency of the conventional DCSK system.Comment: Accepted in the IEEE International Wireless Communications and Mobile Computing Conference (IWCMC 2013

Novel Adaptive Decision Threshold Modulation Technique for UWB Direct Chaotic Communications

A new non-coherent chaotic modulation technique based on adaptive decision threshold is proposed for the UltraWideBand (UWB) Direct Chaotic Communication (DCC) technology. The principal advantages of the proposed technique are: (1) Removing the threshold problem of the classical Chaotic On-Off Keying modulation technique which uses a nonzero decision threshold; (2) Providing a high throughput comparing to the others techniques since it do not uses any delay at the modulation; (3) Reducing the transmitted power, thanks to a transmitted bit energy devised by two. The obtained simulation results show high Bit Error Rate performances of the proposed technique applied in an UWB DCC system. In addition, the new chaotic modulation is more suitable in all DCC-based communications schemes

Data-aided timing synchronization for FM-DCSK UWB communication systems

Frequency-modulated differential chaos shift keying (FM-DCSK) ultrawideband (UWB) communication systems convey information by transmitting ultrashort chaotic pulses (in the nanosecond scale). Since such pulses are ultrashort, timing offset may severely degrade the bit error rate (BER) performance. In this paper, a fast data-aided timing synchronization algorithm with low complexity is proposed for FM-DCSK UWB systems, which capitalizes on the excellent correlation characteristic of chaotic signals. Simulation results show that the BER performance of such systems is fairly close to that of perfect timing thanks to the proposed new algorithm. Moreover, the new algorithm requires less synchronization searching time and lower computa-tional complexity than the conventional one for transmitted reference (TR) UWB systems existing in the current literature

Research on coexistence between CS-DCSK UWB and narrow-band communication systems

分析了密集多径环境下码复用差分混沌移位键控(COdE-SHIfTEd dIffErEnTIAl CHAOS SHIfT kEyIng,CS-dCSk)超宽带(ulTrA WIdEbAnd,uWb)通信系统在单个和多个窄带干扰(nArrOW bAnd InTErfErEnCE,nbI)信号下的比特误码率(bITErrOr rATE,bEr)性能。建立CS-dCSk uWb系统仿真模型,并通过采样扩展方法推导出bEr的表达式,从而得到系统在不同干扰条件下的bEr性能。分析和仿真结果表明,nbI信号对系统有明显干扰作用,但系统性能在不同频率干扰下保持稳定。The performance of code-shifted differential chaos shift keying(CS-DCSK) ultra wideband(UWB) communication system under single or multiple narrow band interferers is analyzed in dense multipath environments.The bit error rate(BER) is derived on the basis of the sampling expansion approach under different interference strengths.The simulations and analyses demonstrate that the NBI signal interferes significantly the performance of system.However,the system performance keeps stable under interferer with different frequencies.国家自然科学基金(61001073;60972053); 欧盟FP7(294923)~

Performance analysis of CS-DCSK over Nakagami-m fading channels

码复用差分混沌移位键控(COdE-SHIfTEd dIffErEnTIAl CHAOS SHIfT kEyIng,CS-dCSk)是一种dCSk的改进方案,其消除了接收机的延时电路,简化了系统实现。为了研究在一般化的多径衰落信道下的性能,基于高斯近似(gAuSSIAnAPPrOXIMATIOn,gA)方法分析了CS-dCSk在nAkAgAMI-M衰落信道下的误比特率(bIT ErrOr rATE,bEr)性能,给出了bEr的数值积分解。计算机仿真验证了分析结果,比较了不同信道参数M条件下的误比特率性能,并分析了原因。The code-shifted differential chaos shift keying(CS-DCSK) is an improved scheme of DCSK,which eliminates the delay circuits in receiver.It simplifies the implementation of system.For the study of the performance of CS-DCSK over the generalization multipath fading channels,based on Gaussian approximation(GA) the BER performance is analyzed over Nakagami-m fading channel.The expression of bit error rate(BER) is presented.Simulation results and numerical results show that the analyzed results are well consistent with the simulation results.And the BERs of different channel parameter m are compared and the reasons are analyzed.国家自然科学基金(61001073)---

Chaotic-based Orthogonal Frequency Division Multiplexing with Index Modulation, Journal of Telecommunications and Information Technology, 2022, nr 4

Orthogonal frequency division multiplexing with index modulation (OFDM-IM), stands out among conventional communication technologies, as it uses the indices of the available transmit entities. Thanks to such an approach, it offers a novel method for the transmission of extra data bits. Recent years have seen a great interest in chaos-based communications. The spectrum-spreading signals used in chaotic signal modulation technologies are orthogonal to the existing mixed signals. This paper presents how well a non-coherent differential chaos shift keying communication system performs across an AWGN. Different types of detection methods are simulated, bit error rate and power spectral density are calculated and then compared with standard OFDM with index modulation. The results of simulations concerning the performance of a DCSK system, adding to the security of the proposed solution and offering a comparable bit error rate performance, are presented in the paper as well

Optimal sub-carriers power allocation in MC-DCSK communication system

研究了多载波差分混沌移位键控(MulTI-CArrIEr dIffErEnTIAl CHAOS SHIfT kEyIng,MC-dCSk)调制中的子载波功率分配问题,基于功率分配模型,推导了MC-dCSk以子载波功率为参数的误比特率(bIT ErrOr rATE,bEr)表达式,基于该表达式,建立了最小化误比特率的最优化问题,并用凸优化方法获得了子载波最优功率的分配策略。通过仿真,比较了最优功率分配与等功率分配情况下,MC-dCSk在加性高斯白噪声(AddITIVE WHITE gAuSSIAn nOISE,AWgn)和rAylEIgH多径衰落信道下的性能,仿真结果验证了最优功率分配策略对系统性能的重要改进,尤其当子载波数较大时,其性能增益更为明显。In this paper,power allocation strategy on sub-carriers of Multi-carrier Differential Chaos Shift Keying( MC-DCSK) is studied.At first,the MC-DCSK system model with power allocated reference and information sub-carriers is presented.Then bit error rate( BER) expression of sub-carriers power allocated MC-DCSK system is derived.Based on the BER expression,the optimal sub-carriers power allocation strategy is obtained by convex optimization.The BER performance of the sub-carriers power allocated MC-DCSK system is evaluated and compared with the conventional MC-DCSK system with equal power allocations under additive white Gaussian noise( AWGN) and Rayleigh multipath fading channels.Simulation results confirm the significant advantages of the optimal sub-carriers power allocation when the number of sub-carriers is large.重庆工程学院校内自然科学基金(2013xzky06)~