Turbo Codes Research Articles

Mathematical model of multichannel discrete-continuous communication channel in conditions of influence of fluctuation noise and intentional interference

A mathematical model based on the synthesis of M-position signals, a method for restoring signal vectors, and intentional interference with quadrature components is presented. The developed model is a formalized description of the discrete-continuous communication channel system. They describe the communication channel and operations for processing, transmission, and protection. The input, output, and internal parameters of the multichannel radio system and the distribution environment are connected. The quadrature method of a mixture of signal, noise, interference at the input of the turbo code decoder is presented. These components are presented in the form of difference equations, which reflect the functional, logical, and structural relationships of the set of communication channels elements and take into account the peculiarities of the signals. This simplifies the technical implementation of the model by using a low-frequency signal instead of high-frequency and more adequately reproduce the properties of the studied system. Noise obstruction, noise interference in the part of the lane, and interference in response are considered. A simulation model with turbo codes has been developed to assess the noise immunity of a programmable radio station using the proposed model of a multi-channel discrete-continuous communication channel. It is used to calculate the average probability of a bit error at the reception without and using a correction code for a discrete communication channel. This confirms the efficiency of using a discrete-continuous channel compared to a discrete-discrete communication channel. The analysis of noise protection of programmed radio stations with the use of the proposed model of multichannel discrete-continuous channel and modulation of FM-2, FM-4, FM-8, KAM-16 is carried out. The obtained graphical dependences with theoretical calculations are compared. As a result, the applicability of the proposed model for the design of transmission channels of programmable radios with turbo codes and MIMO technology in the conditions of intentional interference.

Design and Implementation of Turbo Code and OFDM for Power Line Communication Based on FPGA

Design and Implementation of Turbo Code and OFDM for Power Line Communication Based on FPGA

An Integrated World Modeling Theory (IWMT) of Consciousness: Combining Integrated Information and Global Neuronal Workspace Theories With the Free Energy Principle and Active Inference Framework; Toward Solving the Hard Problem and Characterizing Agentic Causation.

The Free Energy Principle and Active Inference Framework (FEP-AI) begins with the understanding that persisting systems must regulate environmental exchanges and prevent entropic accumulation. In FEP-AI, minds and brains are predictive controllers for autonomous systems, where action-driven perception is realized as probabilistic inference. Integrated Information Theory (IIT) begins with considering the preconditions for a system to intrinsically exist, as well as axioms regarding the nature of consciousness. IIT has produced controversy because of its surprising entailments: quasi-panpsychism; subjectivity without referents or dynamics; and the possibility of fully-intelligent-yet-unconscious brain simulations. Here, I describe how these controversies might be resolved by integrating IIT with FEP-AI, where integrated information only entails consciousness for systems with perspectival reference frames capable of generating models with spatial, temporal, and causal coherence for self and world. Without that connection with external reality, systems could have arbitrarily high amounts of integrated information, but nonetheless would not entail subjective experience. I further describe how an integration of these frameworks may contribute to their evolution as unified systems theories and models of emergent causation. Then, inspired by both Global Neuronal Workspace Theory (GNWT) and the Harmonic Brain Modes framework, I describe how streams of consciousness may emerge as an evolving generation of sensorimotor predictions, with the precise composition of experiences depending on the integration abilities of synchronous complexes as self-organizing harmonic modes (SOHMs). These integrating dynamics may be particularly likely to occur via richly connected subnetworks affording body-centric sources of phenomenal binding and executive control. Along these connectivity backbones, SOHMs are proposed to implement turbo coding via loopy message-passing over predictive (autoencoding) networks, thus generating maximum a posteriori estimates as coherent vectors governing neural evolution, with alpha frequencies generating basic awareness, and cross-frequency phase-coupling within theta frequencies for access consciousness and volitional control. These dynamic cores of integrated information also function as global workspaces, centered on posterior cortices, but capable of being entrained with frontal cortices and interoceptive hierarchies, thus affording agentic causation. Integrated World Modeling Theory (IWMT) represents a synthetic approach to understanding minds that reveals compatibility between leading theories of consciousness, thus enabling inferential synergy.

Performance Optimization of Image Transmission based Turbo and Precoder codes

The amazing performance of the concatenated codes led to attract many researchers to study these characteristics and use theme in many applications in recent years. Because the concatenated code theory is not built from the previous theories, so the characteristics of these codes remain under study and clarification. Recently, the concatenated codes became one of the main options for forward error correcting codes (FEC) in third generation mobile standards such as Universal Mobile Telecommunications System UMTS. This paper investigates the effect joint source –and channel coding which is considered a proficient system for wireless transmission. A new class of FEC is used which is known as a precoder of rate 1 as inner code and non recursive turbo code as outer encoder for hybrid system and then compared with the performance of UMTS turbo code standard for DCT compressed image.

Investigation of error performance in OFDM with network coding techniques in multiple relay networks

Abstract The aim of this paper proposes an orthogonal frequency-division multiplexing (OFDM) with network coding to improve the error performance of the system when the messages are transmitted from user to receiver. Two-way relay (TWR) networks are applied to reduce the transmission time slots. The exclusive-OR (XOR) coding is used for network coding in which source nodes exchange their information via TWR nodes. The XOR coded bits provides redundancy to achieve the transmit diversity gain which improves the error performance of the TWR network. OFDM is exploited for TWR to obtain the frequency selective fading nature of wireless channels. The different modulation schemes such as Quadrature Phase Shift Keying (QPSK), 16-Quadrature Amplitude Modulation (QAM) and 64-QAM with OFDM system are simulated and QPSK is selected as it gives the lowest bit error rate (BER). The multiple relaying schemes with different numbers of the information packets are also considered in this paper. Simulation results show that multiple relay schemes provide faster transmission time and better error rate performance. Moreover, different kinds of channel coding schemes such as Convolutional, Reed-Solomon (RS) and turbo codes are applied in OFDM system with network coding to compare and evaluate the BER performance of the proposed system. From the simulation results, network coded OFDM scheme with turbo codes give better BER performance for given Signal-to-Noise Ratio (SNR) in relaying scheme with different numbers of information packets compared to those of convolutional and RS codes. It shows that, the error rate performance and transmission time is reduced 10 percent than the conventional scheme at even at low SNR value.

Study of Iterative Reception Algorithms for Product Codes Based on Low-Density Codes of Finite Geometries

In this paper, we report the results of studies of iterative algorithms for symbol-by- symbol reception of product codes (block turbo codes) formed using the constituent low-density codes based on finite geometries (Euclidean geometry and projective geometry). The results of modeling and comparative analysis of the specified algorithms of iterative reception for a number of product codes under consideration in the presence of channel interference in the form of additive white Gaussian noise are presented.

Union Bound Evaluation for Non-Binary Turbo Coded Modulations

A method to compute the truncated union bound of non-binary turbo codes mapped to high order modulations is proposed in this letter. It calls for the estimate of the truncated Euclidean distance spectrum. To this end, we identify the error events that limit the Euclidean distance of non-binary turbo codes based on memory-1 convolutional codes defined over GF $(q)$ , $q>2$ . Application examples are elaborated for codes over GF(64). The resulting bounds are found to accurately predict the asymptotic performance of the coded modulation scheme.

RETRACTED ARTICLE: Improved SOVA decoding for UEP wireless transmission of JPEG 2000 images over MIMO-OFDM systems

In this paper, improved Joint Source Channel (JSC) decoding using turbo codes is employed that are unified into JPEG 2000 decoder architecture. Rather than using conventional decoding approach, the proposed system provides reduced BER and complexity. This work deliberates Soft Output Viterbi Algorithm (SOVA) for its real time implementation features. Nevertheless, the algorithm suffers from performance degradation due to optimistic and correlation effects. The objective of this work is to enhance the performance of SOVA by using appropriate reduction factors that integrates and eliminates both these distortions. Acquired Integrated Factor is incorporated in the turbo decoders of the image transmission system. Bit Error rate and Peak Signal to Noise Ratio (PSNR) analysis is made by considering Additive White Gaussian Noise and Rayleigh fading channel through MATLAB simulation. To illustrate the visual quality improvement of the proposed scheme, comparison with other FEC codes is done with significant PSNR gains.

Turbo‐coded secure and reliable quantum teleportation

Quantum teleportation allows an unknown arbitrary quantum state to be transmitted between two separate locations. To achieve this, the system requires both classical and quantum channels, for communicating two classical bits and an entangled quantum bit from the transmitter to the receiver. It is commonly assumed that both channels are error-free, however, under realistic conditions, this is unlikely to be the case. This study proposed and investigated a secure and reliable quantum teleportation scheme when both classical and quantum channels exhibit errors. It was found that the security and reliability of the teleportation could be improved when powerful turbo codes are employed.

Physical Layer Communication via Deep Learning

Reliable digital communication is a primary workhorse of the modern information age. The disciplines of communication, coding, and information theories drive the innovation by designing efficient codes that allow transmissions to be robustly and efficiently decoded. Progress in near optimal codes is made by individual human ingenuity over the decades, and breakthroughs have been, befittingly, sporadic and spread over several decades. Deep learning is a part of daily life where its successes can be attributed to a lack of a (mathematical) generative model. Deep learning empirically fits neural network models to the data, and the result has been extremely potent. In yet other applications, the data is generated by a simple model and performance criterion mathematically precise and training/test samples infinitely abundant, but the space of algorithmic choices is enormous (example: chess). Deep learning has recently shown strong promise in these problems too (example: alphazero). The latter scenario is a good description of communication theory. The mathematical models underlying canonical communication channels allow one to sample an unlimited amount of data to train and test the communication algorithms ((encoder, decoder) pairs) and the metric of bit (or block) error rate allows for mathematically precise evaluation. Motivated by the successes of deep learning in mathematically well defined and extremely challenging tasks of chess, Go, and protein folding, we posit that deep learning methods can play a crucial role in solving core goals of coding theory: designing new (encoder, decoder) pairs that improve state of the art performance over canonical channel models. This manuscript surveys recent advances towards demonstrating this hypothesis, by focusing on strengthening a specific family of coding methods – sequential codes (convolutional codes) and codes that use them as basic building blocks (Turbo codes) – via deep learning methods. New state of the art results are derived on several canonical channels, including the AWGN channel with feedback.

GFDM Based Error Correcting Codes in Underwater Acoustic Channel

In this paper underwater acoustic communication system based on Coded GFDM (CGFDM) is simulated and the performances are analyzed using different error-correcting codes. And also the parameter selection principle of error-correcting code is evaluated. To build practical and high performance CGFDM system the error-correcting codes from low to relatively high computational complexity, such as, convolutional code, RS code, serial concatenated code of RS code plus convo1utional code and turbo code is evaluated. The parameters of code rate, code length, generation polynomial, interleaving and interleaving matrix length are all considered and analyzed elaborately. Finally, the simulating experiments proved that there are some relative1y low complexities systems based on serial concatenated codes of RS code plus convolutional code that are able to gain better performance as the systems based on turbo code.

Design and simulation a video steganography system by using FFT­turbo code methods for copyrights application

Protecting information on various communication media is considered an essential requirement in the present information transmission technology. So, there is a continuous search around different modern techniques that may be used to protect the data from the attackers. Steganography is one of those techniques that can be used to maintain the copyright by employing it to cover the publisher logo image inside the video frames. Nowadays, most of the popular known of the Video-Steganography methods become a conventional technique to the attacker, so there is a requirement for a modern and smart strategy to protect the copyright of the digital video file. Where this proposed system goal to create a hybrid system that combines the properties of Cryptography and Steganography work to protect the copyright hidden data from different attack types with maintaining of characteristics of the original video (quality and resolution). In this article, a modern Video-Steganography method is presented by employing the benefits of TC (Turbo code) to encrypt the pixels of logo image and Least two Significant Bit Technique procedure to embed the encryption pixels inside the frames of the video file. The insertion is performed in the frequency domain by applying the Fast Fourier Transform (FFT)on the video frames. The examination of the suggested architecture is done by terms of Structural Similarity Index, MSE (mean squared error), and PSNR (peak signal-to-noise ratio) by comparing between an original and extracted logo as well as between original and Steganographic video (averaged overall digital frames in the video). The simulation results show that this method proved high security, robustness, capacity and produces a substantial performance enhancement over the present known ways with fewer distortions in the quality of the video

1/n Turbo codes from linear system point of view

The performance of turbo codes at the error floor region is largely determined by the effective free distance, which corresponds to the minimum Hamming weight among all codeword sequences generated by input sequences of weight two. In this paper, we study turbo codes of dimension one obtained from the concatenation of two equal codes and present an upper bound on the effective free distance of a turbo code with these parameters defined over any finite field. We do that making use of the so-called (A, B, C, D) state-space representations of convolutional codes and restrict to the case where A is invertible. A particular construction, from a linear systems point of view, of a recursive systematic convolutional code of rate 1/n so that the effective free distance of the corresponding turbo code attains this upper bound is also presented.

Network‐coded MIMO‐NOMA systems with FEC codes in two‐way relay networks

SummaryThis paper assumes two users and a two‐way relay network with the combination of 2×2 multi‐input multi‐output (MIMO) and nonorthogonal multiple access (NOMA). To achieve network reliability without sacrificing network throughput, network‐coded MIMO‐NOMA schemes with convolutional, Reed‐Solomon (RS), and turbo codes are applied. Messages from two users at the relay node are network‐coded and combined in NOMA scheme. Interleaved differential encoding with redundancy (R‐RIDE) scheme is proposed together with MIMO‐NOMA system. Quadrature phase‐shift keying (QPSK) modulation technique is used. Bit error rate (BER) versus signal‐to‐noise ratio (SNR) (dB) and average mutual information (AMI) (bps/Hz) versus SNR (dB) in NOMA and MIMO‐NOMA schemes are evaluated and presented. From the simulated results, the combination of MIMO‐NOMA system with the proposed R‐RIDE‐Turbo network‐coded scheme in two‐way relay networks has better BER and higher AMI performance than conventional coded NOMA system. Furthermore, R‐RIDE‐Turbo scheme in MIMO‐NOMA system outperforms the other coded schemes in both MIMO‐NOMA and NOMA systems.

DIFFERENT FPGA PRODUCTS BASED IMPLEMENTATION OF LTE TURBO CODE

Abstract —In the long-term evolution (LTE) physical layer, using turbo code is considered as the paramount one in error-correcting coding. This paper presents an implementation of LTE turbo decoding using the Log- Maximum a posteriori (MAP) algorithm with reduced number of required cycles approximately by 75% based on serial to parallel operation. Also an improvement for this algorithm based on polynomial regression function to reduce the implementation complexity. All this system implementation design with 40 bit block size of the input using Xilinx System Generator (XSG). This system implementation in hardware to show its applicability in real time using two approaches; Hardware Co-Simulation and HDL Netlist based on three devices, Xilinx Kintex-7, Spartan-6 and Artix-7. Observe from the hardware implementation, the system become completely real time by controlled from the user using the switches on the board. Also, this system taken the resources utilization from the devices less than other works.

Enhancements on Coding and Modulation Schemes for LTE-Based 5G Terrestrial Broadcast System

Broadcasting and broadband network is moving towards integration and LTE-based 5G terrestrial broadcast is now researched in Release 16 in Third Generation Partnership Project (3GPP) standardization meetings. However, the work scope of LTE-based 5G terrestrial broadcast focuses on specifying new numerologies and some minor improvement on cell acquisition subframe, which is insufficient. In this paper, limitations in coding and modulation schemes of LTE-based 5G terrestrial broadcast system, e.g., Turbo codes and Quadrature Amplitude Modulation (QAM), are detailedly analyzed. To further enhance the spectrum efficiency of LTE-based 5G terrestrial broadcast system, LDPC (Low Density Parity Check) codes from 5G new radio (NR) standard and newly designed non-uniform constellations (NUCs) are adopted in this paper to replace Turbo codes and QAM respectively. Extensive simulations and complexity analysis show that the proposed LDPC coding and NUC modulation scheme, either standalone or combined, can provide significant performance gain over Additive White Gaussian Noise (AWGN) and Tapped Delayline (TDL) channels, without additional complexity. To summarize, this paper investigates the weakness of the coding and modulation schemes in current systems and provides potential alternatives for the enhanced future broadcast in 3GPP standard.

Revisiting the Max-Log-Map Algorithm With SOVA Update Rules: New Simplifications for High-Radix SISO Decoders

This paper proposes a new soft-input soft-output decoding algorithm particularly suited for low-complexity high-radix turbo decoding, called local soft-output Viterbi algorithm (local SOVA). The local SOVA uses the forward and backward state metric recursions just as the conventional Max-Log-MAP algorithm does, and produces soft outputs using the SOVA update rules. The proposed local SOVA exhibits a lower computational complexity than the Max-Log-MAP algorithm when employed for high-radix decoding in order to increase throughput, while having the same error correction performance even when used in a turbo decoding process. Furthermore, with some simplifications, it offers various trade-offs between error correction performance and computational complexity. For instance, employing the local SOVA algorithm for radix-8 decoding of the LTE turbo code reduces the complexity by 33% without any performance degradation and by 36% with a slight penalty of only 0.05 dB. Moreover, the local SOVA algorithm opens the door for the practical implementation of turbo decoders for radix 16 and higher.

5G Systems with Low Density Parity Check based Chanel Coding for Enhanced Mobile Broadband Scheme

The 5G mobile communication standard based radio access technology (RAT) is analysed for implementation of several candidate coding schemes in this paper. The third generation partnership project (3GPP) in the 5G scenario based on the Enhanced mobile broadband (eMBB) scheme is considered. Factors like flexibility, complexity of computation, bit error rate (BER), and block error rate (BLER) are considered for the purpose of evaluation of the coding schemes. In order to evaluate the performance various applications and services, a suitable set is of parameters are provided. The candidate schemes considered for this purpose are polar codes, low density parity check (LDPC) and turbo codes. Fair comparison is performed by investigation of block lengths and obtaining suitable rates by proper design. In an additive white Gaussian noise (AWGN) channel, the performance of BLER / BER is obtained for diverse block lengths and code rates based on simulation. The simulation results show that the performance of LDPC is relatively efficient for various code rates and block lengths despite the better performance of polar codes at short block lengths. As an added advantage, LDPC codes also offer relatively low complexity.

Design and analysis of turbo-coded DCM-OFDM ultra-wideband system with radio-over-fiber and wireless transmission in underwater communication

The performance of radio-over-fiber (ROF) optical transmission and wireless transmission of ultra-wideband (UWB) system administrations is described when operating in the underwater communication. In order to increase the coverage and enhance channel efficiency, ROF system which employs subcarrier multiplexing (SCM) and dense wavelength-division multiplexing (DWDM) is used. DWDM provides efficient channel with tapered channel spacing, whereas SCM’s unique commonality helps in achieving high mobility and large bitrates. The performance of dual-carrier modulation orthogonal frequency-division multiplexing is compared with other modulation techniques, and to indicate an exchange between bit error ration and throughput for the system, our work investigates the punctured turbo coding. For 6 dB Eb/No value, a maximum of 1120 Mbps throughput per band can be accomplished in comparison with 480 Mbps per band of the orthogonal frequency-division multiplexing UWB. To modulate and to develop code designs for a rational UWB-ROF and wireless system in underwater communication with VLC, the proposed study provides a reliable solution.

Colour Light Intensity based Modulation Scheme for Visible Light Communication Employing Turbo Codes

-This paper discusses a modulation scheme based by incorporating the data with the subtle changes in the variation of light intensity for Visible Light Communication (VLC) systems. A modulation scheme named Colour Light Intensity Modulation is proposed on the concept of colour spaces of light where the data can be modulated on the subtle changes in the light signals and transmitted. Firstly, the input data is mapped with the intensities of Light Emitting Diodes and transmitted. The received information is demapped to obtain the estimate of the sent message. The simulation results obtained shows that the proposed concept can be used in the development of more efficient VLC systems.