Chaotic Interleaving Research Articles

Modification of chaotic interleaver for turbo codes with a change to the duffing equation and accounting for the distance spectrum of the code

Various types of interleavers in turbo codes and their parameters affecting the efficiency of turbo codes are considered. It is noted that the type of interleaver directly affects the efficiency and error correcting of turbo codes. Also, the efficiency of turbo codes is influenced by the parameters of the minimum distance, the length of interleaver, and the distance spectrum of the code. A modification of the chaotic interleaver of turbo codes is proposed with the change of the equation to the Duffing and with examining the code's distance spectrum with the condition of increasing the code's distance between the code words with a small weight. The algorithm for modifying the chaotic interleaver with the Duffing equation and with examining the code's distance spectrum of turbo codes is presented. The characteristics of the modified chaotic interleaver with the Duffing equation and with examining the code's distance spectrum of turbo codes according to various parameters of turbo codes are given. This modification of the interleaver of turbo codes increased the minimum distance between elements for different lengths of the interleaver and polynomials of the turbo code by 10 % …33 %. Given this, there was an increase in the energy efficiency of the turbo codes by 0,05, …, 0,25 dB in comparison with a chaotic interleaver without modification at the same value of the bit error probability. When increasing the length of the modified chaotic interleaver with the Duffing equation and applying distance spectrum of the code the increasing the energy efficiency of the turbo code slows down compared to the chaotic interleaver without modification. The application scope of the modified chaotic interleaving with the Duffing equation and with examining the code's distance spectrum of turbo codes is the infocommunication channels for mobile, wired, and satellite communications

On the performance of joint low‐complexity equalization and CFO compensation for SISO‐OFDM communication systems with chaotic interleaving and DCT

SummaryThe implementation of the Orthogonal Frequency Division Multiplexing (OFDM) can be achieved using Inverse Discrete Cosine Transform (IDCT), and DCT instead of Inverse Discrete Fourier Transform (IDFT), and DFT. The Carrier Frequency Offset (CFO) is the main issue of the OFDM system. One of the tools to mitigate the CFO effect and improve the Bit‐Error‐Rate (BER) performance is the equalization procedure. Also, the 1‐Dimension (1‐D), and 2‐Dimension (2‐D) burst errors can be mitigated using a chaotic interleaver in the OFDM system. This consequently improves the BER performance. In this paper, we propose a Joint Low‐Complexity Regularized Linear Zero Forcing (JLCRLZF) equalizer for the OFDM system based on DCT in addition to a chaotic interleaving scheme. The proposed equalizer depends on the concept of the banded‐matrix approximation, and jointly performs the equalization and CFO compensation processes. Simulation results ensure the importance of the proposed JLCRLZF equalizer compared to other algorithms.

Free-space 16-ary orbital angular momentum coded optical communication system based on chaotic interleaving and convolutional neural networks.

Recently, orbital angular momentum (OAM) rays passing through free space have attracted the attention of researchers in the field of free-space optical communication systems. Throughout free space, the OAM states are subject to atmospheric turbulence (AT) distortion leading to crosstalk and power discrepancies between states. In this paper, a novel chaotic interleaver is used with low-density parity-check coded OAM-shift keying through an AT channel. Moreover, a convolutional neural network (CNN) is used as an adaptive demodulator to enhance the performance of the wireless optical communication system. The detection process with the conjugate light field method in the presence of chaotic interleaving has a better performance compared to that without chaotic interleaving for different values of propagation distance. Also, the viability of the proposed system is verified by conveying a digital image in the presence of distinctive turbulence conditions with different error correction codes. The impacts of turbulence strength, transmission distance, signal-to-noise ratio (SNR), and CNN parameters and hyperparameters are investigated and taken into consideration. The proposed CNN is chosen with the optimal parameter and hyperparameter values that yield the highest accuracy, utmost mean average precision (MAP), and the largest value of area under curve (AUC) for the different optimizers. The simulation results affirm that the proposed system can achieve better peak SNR values and lower mean square error values in the presence of different AT conditions. By computing accuracy, MAP, and AUC of the proposed system, we realize that the stochastic gradient descent with momentum and the adaptive moment estimation optimizers have better performance compared to the root mean square propagation optimizer.

MMSE Equalization Based Performance of Chaotic Interleaving Scheme for Iterative IDMA System

Background: In this paper, a chaotic interleaving scheme is proposed for further performance improvement of Interleave Division Multiple Access (IDMA). Interleavers are used to generate permuted sequence of signals to be transmitted with optimum correlation. Methods: Random interleaving (RI) was the fundamental taxonomy and used to distinguish the different users in IDMA scheme. The logistic map based chaotic interleaving scheme is suggested for IDMA. The system is also combined with Minimum Mean Square Error (MMSE) equalizer to combat the effect of Inter Symbol Interference (ISI). Results: For the sake of simplicity, no pulse shaping is assumed at the transmitter and ISI channel is considered to be a fixed 3 tap channel. Simulations are performed in MATLAB. BPSK modulation is used. Furthermore, the results show that the IDMA with proposed logistic map based chaotic interleaver outperforms the traditional random interleaving scheme in terms of BER without the need of extra memory and computational complexity. Conclusion: The obtained results show the noticeable performance improvement of CI-IDMA with MMSE equalization in deep fading situations. Chaos based interleaver also offers other advantages such as less requirement of memory and small implementation complexity.

Performance Analysis and Optimization Based on Adaptive Modulation and Chaotic Interleaving for Helicopter-Satellite Communications

Overcoming periodic blockage of the received signal and the carrier frequency fluctuations caused by rotor blades and Doppler shift, respectively, are considered the most challenging issues in helicopter-satellite communication systems. In this study, we propose an automatic frequency control method based on an adaptive modulation scheme. We employ a hybrid modulation not only depending on quadrature phase shift keying, but also based on binary phase shift keying for accurate cancellation of periodic blockage. On the other hand, we apply a chaotic interleaving scheme with a hybrid modulation scheme in order to achieve a better Bit Error Rate (BER) performance in LOS and NLOS environments. Finally, we validate the mathematical analysis of the proposed scheme through simulations. We evaluated the performance of the proposed scheme and performed a comparison with conventional schemes. Our results show that the proposed scheme is significantly capable of reducing the acquisition time and working with various velocities of helicopter blades in addition to providing a better BER performance in shadow fading environments.

DRPE Encryption with Chaotic Interleaving for Video Communication

Due to the need to transmit encrypted data and video securely through wireless channels, we suggest the application of the double random phase encryption (DRPE) algorithm for efficient video communication over orthogonal frequency division multiplexing (OFDM) system. Moreover, we use an efficient interleaving mechanism on the communicated data depending on chaotic Baker map to control the error level of the channel. In this paper, DRPE and chaotic Baker interleaving are used for efficient video frame transmission over OFDM. Channel equalization is implemented in the proposed scheme. Simulation results illustrate the good performance of the suggested scheme for secure video communication.

Chaotic Interleaving for the Transmission of Compressed Video Frames with Self-Embedded Digital Signatures

This paper presents an efficient video compression and transmission scheme based on the Set Partitioning In Hierarchical Trees (SPIHT) algorithm and chaotic Baker map interleaving. The compressed video frames have self-embedded digital signatures, and the transmission is performed over Orthogonal Frequency Division Multiplexing wireless systems with equalization. The video frames compressed with SPIHT algorithm are primarily converted to the luminance and chrominance scheme for self-watermark embedding, and then the binary format is reconstructed again. Prior to the modulation step, the chaotic randomization is performed on the binary data to encrypt the data to be transmitted and reduce the noise impact of the multipath channel. For performance evaluation, both Rayleigh and additive noise channels are considered for various video frames with chaotic interleaving. The simulation results reveal that the received watermarked video frames with chaotic interleaving applied achieve higher Peak Signal-to-Noise Ratios and correlation coefficients compared to other approaches.

Efficient 3D Watermarked Video Communication with Chaotic Interleaving, Convolution Coding, and LMMSE Equalization

Three-Dimensional Multi-View Video (3D-MVV) transmission over wireless networks suffers from Macro-Blocks losses due to either packet dropping or fading-motivated bit errors. Thus, the robust performance of 3D-MVV transmission schemes over wireless channels becomes a recent considerable hot research issue due to the restricted resources and the presence of severe channel errors. The 3D-MVV is composed of multiple video streams shot by several cameras around a single object, simultaneously. Therefore, it is an urgent task to achieve high compression ratios to meet future bandwidth constraints. Unfortunately, the highly-compressed 3D-MVV data becomes more sensitive and vulnerable to packet losses, especially in the case of heavy channel faults. Thus, in this paper, we suggest the application of a chaotic Baker interleaving approach with equalization and convolution coding for efficient Singular Value Decomposition (SVD) watermarked 3D-MVV transmission over an Orthogonal Frequency Division Multiplexing wireless system. Rayleigh fading and Additive White Gaussian Noise are considered in the real scenario of 3D-MVV transmission. The SVD watermarked 3D-MVV frames are primarily converted to their luminance and chrominance components, which are then converted to binary data format. After that, chaotic interleaving is applied prior to the modulation process. It is used to reduce the channel effects on the transmitted bit streams and it also adds a degree of encryption to the transmitted 3D-MVV frames. To test the performance of the proposed framework; several simulation experiments on different SVD watermarked 3D-MVV frames have been executed. The experimental results show that the received SVD watermarked 3D-MVV frames still have high Peak Signal-to-Noise Ratios and watermark extraction is possible in the proposed framework.

Performance of turbo-coded chaotic interleaving and frequency-domain equalization scheme for high speed OFDM-based PLC systems

In this paper, we propose a turbo coded-chaotic interleaving and frequency-domain equalization scheme for high speed OFDM-based powerline communication (PLC) systems. The proposed scheme is composed of two stages as follows. At stage 1, the chaotic interleaver is introduced to replace the random interleaver usually used in conventional turbo codes. It generates permuted version from the sample sequence to be transmitted with low correlation among their samples, leading to better bit error rate (BER) and security performance. At stage 2, the frequency-domain equalizer uses a new clipping/blanking function to estimate the impulsive noise samples after OFDM demodulation. The proposed method combines the advantages of having excellent error correction capability with low complexity, high security, and efficient impulsive noise cancellation without a prior knowledge about the characteristics of impulsive noise. Computer simulation results reveal that the proposed scheme achieves better BER performance in comparison to the conventional block interleaving. Furthermore, the obtained results show that this scheme with frequency-domain equalization provides a good trade-off between system performance and bandwidth efficiency.

Continuous Phase Modulation with Chaotic Interleaving for Different OFDM Versions

In this paper, we propose a chaotic interleaving scheme for efficient data transmission with continuous-phase modulation orthogonal frequency-division multiplexing (CPM-OFDM) systems over fading channels. The idea of chaotic maps randomization (CMR) is exploited in this scheme. CMR generates permuted sequences from the sequences to be transmitted with lower correlation among their samples, and hence a better symbol error rate (SER) performance can be achieved. The performance of the proposed approach is tested on the conventional Fast fourier transform OFDM (FFT-OFDM), discrete wavelet transform OFDM (DWT---OFDM), and discrete cosine transform OFDM (DCT---OFDM). The proposed (FFT/DCT/DWT)-CPM-OFDM system with interleaving combines the advantages of frequency diversity and power efficiency from CPM-OFDM and performance improvement from chaotic interleaving. The SER performance of the (FFT/DCT/DWT)-CPM-OFDM system with and without chaotic interleaving is evaluated by computer simulations. Also, a comparison between chaotic interleaving and block interleaving is performed. Simulation results show that the chaotic interleaving scheme can greatly improve the performance of (FFT/DCT/DWT)-CPM-OFDM systems. Furthermore, the results show also that, the (FFT/DCT/DWT)-CPM-OFDM system provides a good trade-off between system performance and bandwidth efficiency.

Compressed Watermarked Video Frame Transmission System Using Chaotic Interleaving

In this paper, we propose a chaotic Baker interleaving approach for efficient spiht compressed steganography watermarked frame of transmission of video over (OFDM) wireless systems with equalization. Cases of Rayleigh fading channels and additive white Gaussian noise are considered. The spiht compressed steganography watermarked video frames is primarily converted to approach of chrominance and after that the chrominance approach is converted to a binary data format. Prior to the modulation step made interleaving on the binary data. The proposed chaotic interleaving approach made reducing in the channel effects on the data which it is transmitted and made adding a degree of encryption to the transmitted data. The big data of the video frames is reduced by madding spiht compressed technique. To test the performance of the proposed approach by the transmission of spiht compressed steganography watermarked video various frames over additive white Gaussian noise and Rayleigh fading channels with interleaving by chaotic baker map. The results of the experiments explain that the received compressed steganography watermarked video frames are gives higher peak signal to noise ratios (PSNRs) with applied chaotic interleaving compared with other approaches and also show the histogram count of the correlation coefficient of the watermarked blocks.

Continuous phase modulation with chaotic interleaving for optical OFDM systems

Orthogonal frequency division multiplexing (OFDM) based multi-carrier system has attained a great success in modern wireless and optical communication systems. Unfortunately, the peak-to-average power ratio (PAPR) problem raised from multi-carriers is a well-rooted problem in OFDM systems that occasionally drives high power amplifier in the transmitter to operate in the nonlinear region of its characteristic curve, and hence it causes severe deterioration in its performance. This paper presents a new scheme to mitigate the effect of PAPR in optical OFDM system using continuous phase modulation with a chaotic interleaver based on Backer map. Moreover; frequency domain equalization using zero forcing equalizer and minimum mean square equalizer is employed to avoid the complexity and further enhance the overall performance of the system. Numerical results and simulations have been carried out to show the remarkable improvement achieved over the previous studies.

On the Performance of FFT/DWT/DCT-based OFDM Systems with Chaotic Interleaving and Channel Estimation Algorithms

The efficiency of data transmission over fading channels in orthogonal frequency division multiplexing (OFDM) systems depends on the employed interleaving method. In this study, we propose an improved chaotic interleaving scheme which aims to improve the performance of OFDM system under fading channel. In the proposed scheme, the binary data is interleaved with chaotic Baker map prior to the modulation process. In the sequel, significant degree of encryption is being added during data transmission. The performance of the proposed approach is tested on the conventional fast Fourier transform OFDM, discrete wavelet transform OFDM, and discrete cosine transform OFDM with and without chaotic interleaving. Furthermore, an expectation---maximization (EM) algorithm is proposed for improving channel impulse response (CIR) estimation based on a maximum likelihood principle. The proposed scheme makes use of EM algorithm to update the channel estimates until convergence is reached. The simulation results show the efficiency of the proposed algorithms under Rayleigh fading environments where the symbol error rate essentially coincides with that of the perfect channel case after the fifth EM iteration.

Chaotic Interleaving for Robust Image Transmission with LDPC Coded OFDM

This paper presents a new technique for progressive image transmission over low-density parity-check coded orthogonal frequency division multiplexing (LDPC-OFDM) system. This technique adopts chaotic Baker map to improve the performance and reduce the peak-to-average power ratio (PAPR) of the OFDM signal. It helps improving the error resilient ability and also enhancing the efficiency of progressive image transmission over frequency selective fading channels. The proposed technique can effectively resist the fading impact of the frequency selective channels using simple frequency domain equalization. The proposed technique also utilizes the set partitioning in hierarchical trees as a source coding algorithm for the transmitted images. The distinctive feature of the proposed technique is that the transmitted data sequence has less data correlation, which leads to minimizing the PAPR. Simulation results show that the proposed technique improves the visual quality of the received images and reduces the PAPR of the OFDM signal as well.

Performance enhancement of power line communication systems with efficient low density parity-check codes, noise removal, equalization, and chaotic interleaving

Power Line Communication (PLC) offers a convenient and inexpensive medium for high-speed data transmission; however, this technology still faces difficult challenges. In particular, the Power Line (PL) channel suffers from multipath propagation accompanied with frequency-selective fading. This paper presents a method for constructing Low Density Parity-Check (LDPC) codes for Forward Error-Correction (FEC) on PL channel combined with Chaotic Interleaving (CI) and linear equalization to compensate for burst errors and multipath effects. First, the PL channel characteristics are introduced. A new way of noise modeling, which takes into account both background and impulse noises, is presented. Unlike Middletonʼs class A noise model, the proposed model is suitable for PLC channel. Noise bursts last no longer than 0.1 ms and they are characterized by Poisson distribution with an impulse arrival rate of 0⩽λ⩽5×10−3. In addition, we present a new algorithm for detection and removal of the impulse noise, by which a gain of 1.5 dB could be obtained. Concerning the system design, Zimmermannʼs model for PLC channel is considered, and then the proposed LDPC code construction method is presented. A Modified Shortest-Path (MSP) algorithm of low complexity is applied to obtain a code graph of the desired structure. The parity-check matrix of the code is constructed column-by-column subject to bit-degree and girth constraints. Both high rate and high girth codes have been constructed, e.g., code rates of 0.94, 0.95, 0.96, and 0.97. For better decoding of LDPC codes, an accurate estimation of Signal-to-Noise Ratio (SNR) is required. Therefore, we introduce a new method for SNR estimation based on higher-order signal statistics. The proposed method is especially beneficial at low SNRs. Furthermore, to achieve better immunity to burst and impulse noise, a novel interleaving scheme based on chaotic Baker map is proposed. Eventually, transmission of images on PL channel has been carried out using computer simulations. Clear images were reconstructed and the proposed algorithms were shown to perform well over PLC channel.

Chaotic Interleaving for Secured OFDM

Chaotic Interleaving for Secured OFDM

JPEG image transmission over mobile network with an efficient channel coding and interleaving

This article studies improving of coloured JPEG image transmission over mobile wireless personal area network through the Bluetooth networks. This article uses many types of enhanced data rate and asynchronous connectionless packets. It presents a proposed chaotic interleaving technique for improving a transmission of coloured images over burst error environment through merging it with error control scheme. The computational complexity of the used different error control schemes is considered. A comparison study between different scenarios of the image transmission is held in to choose an effective technique. The simulation experiments are carried over the correlated fading channel using the widely accepted Jakes’ model. Our experiments reveal that the proposed chaotic interleaving technique enhances quality of the received coloured image. Our simulation results show that the convolutional codes with longer constraint length are effective if its complexity is ignored. It reveals also that the standard error control scheme of old Bluetooth versions is ineffective in the case of coloured image transmission over mobile Bluetooth network. Finally, the proposed scenarios of the standard error control scheme with the chaotic interleaver perform better than the convolutional codes with reducing the complexity.

Image transmission over mobile Bluetooth networks with enhanced data rate packets and chaotic interleaving

Bluetooth is a wireless personal area network. This type of networks is widely used for image communication. This paper presents a study for the transmission of images over mobile Bluetooth networks. It presents a novel chaotic interleaving scheme for this purpose. In this scheme, the chaotic Baker map is used for bit interleaving and enhanced data rate packets are used for data transmission. In the proposed scheme, the chaotic interleaver can be applied on the whole bit stream or on a packet-by-packet basis. The proposed scheme is applied with 2DH1, 2DM1, 3DH5, and 3DM5 packets. A comparison study between the proposed scheme and the traditional interleaving schemes for image transmission over correlated and uncorrelated fading channels is presented. The simulation results show the superiority of the proposed scheme over the traditional schemes. The proposed scheme also adds a degree of security to data transmission.

Performance of the audio signals transmission over wireless networks with the channel interleaving considerations

This article studies a vital issue in wireless communications, which is the transmission of audio signals over wireless networks. It presents a novel interleaver scheme for protection against error bursts and reduction the packet loss of the audio signals. The proposed technique in the article is the chaotic interleaver; it is based on chaotic Baker map. It is used as a randomizing data tool to improve the quality of the audio over the mobile communications channels. A comparison study between the proposed chaotic interleaving scheme and the traditional block and convolutional interleaving schemes for audio transmission over uncorrelated and correlated fading channels is presented. The simulation results show the superiority of the proposed chaotic interleaving scheme over the traditional schemes. The simulation results also reveal that the proposed chaotic interleaver improves the quality of the received audio signal. It improves the amount of the throughput over the wireless link through the packet loss reduction.

Enhancing the Image Transmission over Wireless Networks through a Novel Interleaver

With increasing the using of wireless technologies in essential fields such as the medical application, this paper proposes different scenarios for the transmission of images over wireless networks. The paper uses the IEEE ZigBee 802.15.4 for applying the proposed schemes. It is a Wireless Personal Area Network (WPAN). This paper presents a novel chaotic interleaving scheme against error bursts. Also, the paper studies the proposed interleaver with the convolutional code with different constraint lengths (K). A comparison study between the standard scheme and proposed schemes for image transmission over a correlated fading channel is presented. The simulation results show the superiority of the proposed chaotic interleaving scheme over the traditional schemes. Also, the chaotic interleaver packet-by-packet basis gives a high quality image with (K=3) and reduces the need for the complex encoder with K=7.