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![The conventional DS/SS system [11]](publication/258398206/figure/fig1/AS:1089053470523426@1636661989424/The-conventional-DS-SS-system-11_Q320.jpg)
This paper proposes a chaos-based secure direct-sequence/spread-spectrum (DS/SS) communication system which is based
on a novel combination of the conventional DS/SS and chaos techniques. In the proposed system, bit duration is varied according
to a chaotic behavior but is always equal to a multiple of the fixed chip duration in the communication p...
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Citations
... In these techniques, the communication efficiency decreases and also receiver requires enough time to de-spread the message. Nguyen Xuan Quyen et al. [7] discussed a chaosbased DSSS; the message bit duration is varied according to a chaotic behaviour, and these data bits are spread with a pseudo-noise (PN) sequence. The receiver requires an identical regeneration of both PN sequence and also the chaotic behaviour to improve the data security significantly. ...
Physical layer performance of wireless communication, which is subjected to reactive jamming attack, is analyzed in this paper. The main problem in conventional direct sequence spread spectrum (DSSS) is the requirement of pre-shared key between sender and receiver. Many researchers focused to remove pre-shared keys for anti-jamming communication, but in those techniques, it requires enough time to de-spread the data. So to overcome the problem of pre-shared key and to enhance the security of wireless communication with minimum de-spreading time, chaos-based code selection (CCS) DSSS has been proposed in this paper. Matlab simulation results show that our proposed technique CCS DSSS indicates much better performance when compared with other unshared secret spreading keys in terms of security and de-spreading time. The de-spreading time required to extract the original message of size 512 bits is almost 0.05888 ms, which is minimum compared with other unshared secret spreading key spread spectra.
... The chaotic maps under finite precision have been focus of research community due to numerous applications, such as secure communications [1][2][3][4][5][6], random number generation [7] and cryptography [4,[8][9][10][11]. Aforementioned applications require digital chaotic maps with larger period, higher randomness and nonlinearity in order to provide higher resistance against cryptanalysis. ...
In cryptographic algorithms, random sequences of longer period and higher nonlinearity are always desirable in order to increase resistance against cryptanalysis. The use of chaotic maps is an attractive choice as they exhibit properties that are suitable for cryptography. In continuous phase space of the logistic map, proper control parameters and initial state result into aperiodic trajectories. However, when the phase space of the logistic map is quantized, the trajectories terminate in finite and stable periodic orbits due to quantization error. The dynamic degradation of the logistic map can be mitigated using nonlinear feedback and cascading multiple chaotic maps. We propose a logistic map-based, finite precision multi-dimensional logistic map, that incorporates nonlinear feedback and modulus operations to perturb the chaotic trajectories. We present complexity, average cycle length and randomness analysis to evaluate the proposed method. The simulation results and analysis reveal that the proposed MDLM approach achieves longer period and higher randomness.
... Virtually all circuits use correlators or coherent filters to evaluate the binary signal on the receiving side. However, recently, based on the ergodicity of the chaotic signal, a simple technique for evaluating chaotic parameters in a noisy environment was introduced [4][5][6]. At the beginning of this approach, the proposed modification of the new ergodic chaotic on-off manipulation (Ergodic Shaotic Оn-Off Keying, E-COOK) for a digital communication scheme with logistic mapping is proposed. ...
... The nonzero values of cross-correlation amongst other users' sequences can cause popping up an issue of Multiple Access Interference (MAI), which is considered a main limiting factor to system's BER performance and capacity [3]. The lower randomization and short complexity, and periodicity, they cause a weakened security trouble (High probability Interception (HPI)) and less number of generated sequences (lower capacity) [4]. However, many of designed schemes for generating chaotic sequences [5,6] based on 1D Logistic ...
... These are variation bit duration, sensitive dependence to initial conditions (x 0 ,y 0 ,z 0 ) and mismatching system's parameters (ρ,μ,γ) [20].Unlike PN-sequences , the OCCSs(̂,̂,̂) and Logistic Map have variable bit duration [20],which puts difficult barriers in front intruder that tries to break down the spreading sequences and hack the desired data. Even though [29,30] had proposed attacker methods to decipher the spreading sequences ,the initial conditions (x 0 ,y 0 ,z 0 ) and system's parameters (ρ,μ,γ) of OCCSs provide a super security keys for DS/SS-CDMA system ,therefore, it is difficult for the eavesdropper to decode the spreading sequences and capture information [4]. As shown in Figure 10, the security level of DS/SS-CDMA system against an intruder increases when a small mismatch is occurred in initial conditions or chaotic parameters between transmitter and target receiver ; this leads up to increasingly reproduce bit errors in symbols QPSK modulation. ...
... In addition, multi-user spreadspectrum modulation schemes and chaos have been proposed in literature, see e.g. [25][26][27] . ...
Background and objectives:
Currently, telemedicine is levered upon the improvement in communication network technology such as Body Area Sensor Networks (BASN) to provided biomedicine solutions. Nevertheless, information security is an important issue since biomedical data is exchanged through insecure channels, which exposes private information that can be intercepted by malicious intruder. Therefore, secure communication protocols for multiuser networks in telemedicine applications are a big challenge. Recent chaos-based encryption works have been conducted in the area of medical secure communications with high security capabilities. However, none of them has considered multiuser network, which is used in several e-health applications. Up to our knowledge, the proposed protocol is the first attempt to consider this service in secure telemedicine. In this paper, we propose a novel scheme based on binary phase-shift key (BPSK) and chaos to provide information security at biosignals in a multiuser network system transmitting data over single channel.
Methods:
The proposed scheme uses the two-dimensional Hénon map with enhance pseudorandom sequences and CDMA technique to achieve multiuser encryption process and transmit data over a single channel. We use biosignals such as electrocardiograms (ECG) and blood pressure (PB) signals from PhisioBank ATM data base for simulation results at MatLab software. We evaluate the security and performance by determining the secret key space, secret key sensitivity, resistance against noise attack with quality analysis by using BER, MSE, and PSNR, encryption-decryption time, and throughput.
Results:
In simulations tests, biosignals of ECG and BP in a BANS network are encrypted and transmitted over shared wireless channels and just authorized medical personal can retrieve such information with corresponding secret key from the cryptogram, that appears as noise to any intruder. The proposed multiuser scheme support high noise and interference attacks efficiently in contrast with classic chaos-based encryption works for telemedicine, where some scenarios are simulated with very low BER, very low MSE, and high PSNR between plain biosignals and recovered biosignals when high AWGN noise is added to encrypted-transmitted signal. In addition, the encryption process presents enough key space and high sensitivity at secret key. A comparative analysis of proposed method and recent existing works was also presented.
Conclusions:
Patients can be monitored and diagnosed opportunely remotely and all their medical information is transmitted securely to the correct specialist. Also, it is possible to transmit several electrophysiological signals in a single channel in a secure multiuser network at low cost optimizing the use of available bandwidth for telemedicine applications.
... Binary sequences with good pair wise cross-correlation generated by various chaotic maps can be used in CDMA systems [9]. The advantages, such as: interference rejection, antijamming, fading reduction, multi-access potential and low probability of interception, of using direct sequence spread spectrum (DSSS) making use of the chaotic sequence is given in [10]. ...
Collaborative multi-user transmission and detection is a contemporary technique used for the up-link of code-division multiple access (CDMA). CDMA has contributed much to the field of wireless communication and still addresses many of the capacity and security requirements. The collaborative multi-user technique achieves an increase in capacity by sharing the spreading sequences among the users. In such grouped CDMA schemes, the sum of large numbers of statistically uncorrelated pseudo-random (PN) sequences results in multiple access interference. This restricts the number of PN sequences available for spreading, thereby limiting the total number of full rate users. Furthermore, PN sequences can be detected by their bit timings and consequently the security of the users’ data is a matter of concern. To solve this problem, a novel high-capacity and secure system, called the 1D-Bernoulli-chaotic-collaborative-CDMA (BCC-CDMA), is proposed. In the BCC-CDMA, a set of specific ‘initial-conditions’ are used, and identified for the 1D-Bernoulli Map, that generates row elements of an N × N matrix of mutually orthogonal chaotic sequences,. The ith row of this matrix acts as the spreading sequence for the ith group of collaborating users in BCC-CDMA. The proposed scheme eliminates the constraints in security and user capacity outperforming the existing multi-user detection schemes. Simulations show the bit-error-rate performance of BCC-CDMA supporting 120 full-rate users compared to the almost 90 and 30 users offered by conventional schemes.
... For communications, chaos theory has been extensively investigated and many brand new chaos-based communication schemes have been reported: optical links using chaotic pulse positioning [6], wireless links transmitting chaotic signals [7], spreadspectrum communication systems using chaotic signals [8], secured communication systems and links encrypted with chaos [9][10][11][12][13]. All these systems and approaches revolve around one core element which is the source of chaotic dynamics: the chaos generator. ...
In this paper we will describe the use of Matlab/Simulink without third party toolboxes as a single integrated environment to study and generate the HDL description of chaotic systems for rapid prototyping purposes. We will provide a review of different approaches to implement chaos generators in both analogue and digital forms with a focus on digital one. We will present a rapid prototyping method of digital chaos generators on FPGAs that is of great use for a seamless study, simulation and implementation of those systems in one environment. This will ease the design phase of the chaotic systems and will provide more flexibility for their study. Multiple chaos generators, such as Lorenz, Rössler, Chua, Linz-Sprott, and Sprott types have been designed using this method to showcase its effectiveness. In addition, for a better investigation of the chaotic dynamics, this work makes use of an implementation scheme that permits the visualization of the 3D chaotic attractor on the oscilloscope. The main focus of this paper is to provide a common implementation framework of chaos generators to target various applications, mainly cryptographic one. Newcomers to the field will easily dive in and active researchers will be able to speak the same language and build upon one anothers works more efficiently by adopting the presented guidelines.
... In [6] high-efficiency DCSK (HE-DCSK) introduced to combat with this drawback, but HE-DCSK is difficult to implement. The Chaotic Direct-Sequence Spread-Spectrum (CDSSS) method was used in [7][8][9] for perfor- mance enhancement in noisy channels. Several methods have been proposed for performance improvement of DCSK modulation. ...
In this paper, we introduce a grouping approach for power allocation in the multi-user OFDM-DCSK (MU-OFDM-DCSK) system under the frequency selective fading channels. The suggested procedure is convenient also for the other comb-type non-coherent schemes with similar structure. Furthermore, we derive analytical bit error rate (BER) expression for the grouped scheme and offer an optimal power distribution policy for both the single- and multi-user scenarios. This power assignment strategy is formulated by a min-max problem with the target of the worst group BER minimization incorporating total power and interference constraints. Simulation results confirm the advantages of the proposed power allocation scheme.
... Since these discoveries, various digital communication systems, have *Correspondence: leonard.novosel@fer.hr University of Zagreb, Faculty of electrical engineering and computing, Unska 3, Zagreb, Croatia been developed with chaotic signals[3,[5][6][7][8][9][10]with further advances in different fields of chaotic modulation techniques[11][12][13][14][15]. Chaotic systems display interesting properties that can be used in digital communication systems. ...
... Chaotic sequences can be used instead of pseudo-random sequences in cryptography, spreadspectrum systems, image, and video coding. Research in using chaotic sequences in spread spectrum for multiple access has been made before[3,[6][7][8][9][19][20][21]with some implementations in various hardware architectures[10,22,23]. This paper was inspired by previous work on simulated chaotic spread-spectrum system models. ...
In this paper, bit error performance evaluation of chaotic sequences is presented. Performance of chaotic sequences is evaluated on multiple access spread spectrum system model for USRP software defined radio. LabVIEW is used to perform numerical simulations and bit error rate analysis. Chaotic sequences of different lengths are generated using one-dimensional, two-dimensional, and three-dimensional maps. It is expected that sequences generated from complex maps will have better multiple access performance. Performance of chaotic sequences is evaluated against orthogonal sequences in multiple access scenario. Using Golay figure of merit and Pearson correlation coefficient, analysis of correlation properties and a comparison is performed on orthogonal and chaotic sequences for correlation properties comparison. The results show that chaotic sequences from two-dimensional maps have lower bit error rate than orthogonal and other chaotic sequences. Comparison of correlation properties shows that sequences with a low figure of merit and low Pearson coefficient have lower bit error rate. Those results can be used to generate chaotic sequences with desired correlation properties.
... The proposed system inherits capabilities like interference rejection, antijamming, fading reduction, and low probability of interception from the conventional direct sequence spread spectrum (DSSS) systems [7]. In conventional DSSS systems, the users transmit their information using Walsh functions or wavelets [8]. ...
Code-division multiple access (CDMA) has played a remarkable role in the field of wireless communication systems, and its capacity and security requirements are still being addressed. Collaborative multiuser transmission and detection are a contemporary technique used in CDMA systems. The performance of these systems is governed by the proper accommodation of the users and by proper synchronization schemes. The major research concerns in the existing multiuser overloaded CDMA schemes are (i) statistically uncorrelated PN sequences that cause multiple-access interference (MAI) and (ii) the security of the user’s data. In this paper, a novel grouped CDMA scheme, the 1D-Bernoulli chaotic collaborative CDMA (BCC-CDMA), is introduced, in which mutually orthogonal chaotic sequences spread the users’ data within a group. The synchronization of multiple groups in this scheme has been analyzed under MAI limited environments and the results are presented. This increases the user capacity and also provides sufficient security as a result of the correlation properties possessed by the chaotic codes. Multigroup synchronization is achieved using a 1D chaotic pilot sequence generated by the Bernoulli Map. The mathematical model of the proposed system is described and compared with the theoretical model of the synchronization in CDMA, the simulation results of which are presented.
