scholarly journals Extrinsic Information Transfer Charts for Characterizing the Iterative Decoding Convergence of Fully Parallel Turbo Decoders

IEEE Access ◽  
2015 ◽  
Vol 3 ◽  
pp. 2100-2110 ◽  
Author(s):  
Hoang Anh Ngo ◽  
Robert G. Maunder ◽  
Lajos Hanzo
Keyword(s):  
Iterative Decoding ◽  
Information Transfer ◽  
Extrinsic Information ◽  
Turbo Decoders

Application of Extrinsic Information Transfer Charts to Anticipate Turbo Code Behavior

2013 ◽  
pp. 97-104
Author(s):  
Izabella Lokshina
Keyword(s):  
Turbo Codes ◽  
Iterative Decoding ◽  
Information Transfer ◽  
Turbo Code ◽  
A Priori ◽  
Substantial Reduction ◽  
International Standards ◽  
Extrinsic Information ◽  
Exit Chart ◽  
Analysis Technique

This paper examines turbo codes that are currently introduced in many international standards, including the UMTS standard for third generation personal communications and the ETSI DVB-T standard for Terrestrial Digital Video Broadcasting. The convergence properties of the iterative decoding process associated with a given turbo-coding scheme are estimated using the analysis technique based on so-called extrinsic information transfer (EXIT) chart. This approach provides a possibility to anticipate the bit error rate (BER) of a turbo code system using only the EXIT chart. It is shown that EXIT charts are powerful tools to analyze and optimize the convergence behavior of iterative systems utilizing the turbo principle. The idea is to consider the associated SISO stages as information processors that map input a priori LLR’s onto output extrinsic LLR’s, the information content being obviously assumed to increase from input to output, and introduce them to the design of turbo systems without the reliance on extensive simulation. Compared with the other methods for generating EXIT functions, the suggested approach provides insight into the iterative behavior of linear turbo systems with substantial reduction in numerical complexity.

Application of Extrinsic Information Transfer Charts to Anticipate Turbo Code Behavior

2011 ◽  
Vol 3 (2) ◽  
pp. 31-37 ◽  
Author(s):  
Izabella Lokshina
Keyword(s):  
Turbo Codes ◽  
Iterative Decoding ◽  
Information Transfer ◽  
Turbo Code ◽  
A Priori ◽  
Substantial Reduction ◽  
International Standards ◽  
Extrinsic Information ◽  
Suggested Approach ◽  
Exit Chart

This paper examines turbo codes that are currently introduced in many international standards, including the UMTS standard for third generation personal communications and the ETSI DVB-T standard for Terrestrial Digital Video Broadcasting. The convergence properties of the iterative decoding process associated with a given turbo-coding scheme are estimated using the analysis technique based on so-called extrinsic information transfer (EXIT) chart. This approach provides a possibility to anticipate the bit error rate (BER) of a turbo code system using only the EXIT chart. It is shown that EXIT charts are powerful tools to analyze and optimize the convergence behavior of iterative systems utilizing the turbo principle. The idea is to consider the associated SISO stages as information processors that map input a priori LLR’s onto output extrinsic LLR’s, the information content being obviously assumed to increase from input to output, and introduce them to the design of turbo systems without the reliance on extensive simulation. Compared with the other methods for generating EXIT functions, the suggested approach provides insight into the iterative behavior of linear turbo systems with substantial reduction in numerical complexity.

Digital Communications and a Smart World

2019 ◽  
pp. 136-163
Author(s):  
Hua Zhong
Keyword(s):  
Turbo Codes ◽  
Iterative Decoding ◽  
Communication Systems ◽  
Information Transfer ◽  
Turbo Code ◽  
Digital Communications ◽  
Substantial Reduction ◽  
International Standards ◽  
Extrinsic Information ◽  
Likelihood Ratios

This chapter is devoted to digital communications in a smart world. The author examines turbo codes that are currently introduced in many international standards and implemented in numerous advanced communication systems, applied in a smart world, and evaluate the process of extrinsic information transfer (EXIT). The convergence properties of the iterative decoding process, associated with a given turbo-coding scheme, are estimated using the analysis technique based on so-called EXIT charts. This approach provides a possibility to predict the bit-error rate (BER) of a turbo code system with only the extrinsic information transfer chart. The idea is to consider the associated soft-input soft-output (SISO) stages as information processors, which map input a priori log likelihood ratios (LLRs) onto output extrinsic LLRs. Compared with other methods, the suggested approach provides insight into the iterative behavior of linear turbo systems with substantial reduction in numerical complexity.

scholarly journals Convergence analysis of the unpunctured turbo trellis-coded modulation (UTTCM)

2019 ◽  
Vol 13 (2) ◽  
pp. 447
Author(s):  
Ahmed Haffane ◽  
Abdelhafid Hasni ◽  
Mustapha Khelifi ◽  
Boufeldja Kadri
Keyword(s):  
Gaussian Noise ◽  
Iterative Decoding ◽  
Information Transfer ◽  
Additive White Gaussian Noise ◽  
Coded Modulation ◽  
Extrinsic Information ◽  
Trellis Coded Modulation ◽  
Exit Chart ◽  
Trellis Coded ◽  
Simulation Results

In this paper, the performance of the Unpunctured Turbo Trellis-Coded Modulation (UTTCM) over Additive White Gaussian Noise (AWGN) channel is analyzed using the non-binary extrinsic information transfer (EXIT) chart. The exchange of the extrinsic information between the decoder components is tracked, allowing the generation of an EXIT chart, which is a powerful tool for analyzing the convergence behavior of iterative decoding and prediction of convergence position. The Simulation results are compared with the turbo cliff positions on the BER curves.

scholarly journals On the Performance of Self-Concatenated Coding for Wireless Mobile Video Transmission Using DSTS-SP-Assisted Smart Antenna System

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Nasru Minallah ◽  
Ishtiaque Ahmed ◽  
Muhammad Ijaz ◽  
Atif Sardar Khan ◽  
Laiq Hasan ◽  
...  
Keyword(s):  
Iterative Decoding ◽  
Information Transfer ◽  
Video Transmission ◽  
Smart Antenna ◽  
Video Quality ◽  
Sphere Packing ◽  
Antenna System ◽  
Video Codec ◽  
Extrinsic Information ◽  
High Data

In the current age of advanced technologies, there is an escalating demand for reliable wireless systems, catering to the high data rates of mobile multimedia applications. This article presents a novel approach to the concept of Self-Concatenated Convolutional Coding (SECCC) with Sphere Packing (SP) modulation via Differential Space-Time Spreading- (DSTS-) based smart antennas. The two transmitters provide transmit diversity which is capable of recuperating the signal from the effects of fading, even with a single receiving antenna. The proposed DSTS-SP SECCC scheme is probed for the Rayleigh fading channel. The SECCC structure is developed using the Recursive Systematic Convolutional (RSC) code with the aid of an interleaver. Interleaving generates randomness in exchange for extrinsic information between the constituent decoders. Iterative decoding is invoked at the receiving side to enhance the output performance by attaining fruitful convergence. The convergence behaviour of the proposed system is investigated using EXtrinsic Information Transfer (EXIT) curves. The performance of the proposed system is ascertained with the H.264 standard video codec. The perceived video quality of DSTS-SP SECCC is found to be significantly better than that of the DSTS-SP RSC. To be more precise, the proposed DSTS-SP SECCC system exhibits an E b / N 0 gain of 8 dB at the PSNR degradation point of 1 dB, relative to the equivalent rate DSTS-SP RSC. Similarly, an E b / N 0 gain of 10 dB exists for the DSTS-SP SECCC system at 1 dB degradation point when compared with the SECCC scheme dispensing with the DSTS-SP approach.

scholarly journals An Improved Design of Gallager Mapping for LDPC-coded BICM-ID System

2016 ◽  
Vol 20 (1) ◽  
pp. 16 ◽  
Author(s):  
Lin Zhou ◽  
Weicheng Huang ◽  
Shengliang Peng ◽  
Yan Chen ◽  
Yucheng He
Keyword(s):  
Iterative Decoding ◽  
Information Transfer ◽  
Hamming Distance ◽  
Coded Modulation ◽  
Spectrum Efficiency ◽  
Modulation Scheme ◽  
Optimized Design ◽  
Extrinsic Information ◽  
Improved Design ◽  
Bit Interleaved Coded Modulation

Gallager mapping uses different signal points with different probabilities by assigning several labels for one signal point, and thus provides a promising approach to achieving shaping gains. An important issue in Gallager mapping is how to assign labels for signal points. In this paper, two optimized design rules for Gallager mapping of bit-interleaved coded modulation scheme with iterative decoding (BICM-ID) are proposed, where the Hamming distance among the labels for one signal point should be minimized. The extrinsic information transfer (EXIT) technique is utilized to design and analyze the proposed mapping patterns. Compared with conventional Gallager mapping, our proposed method provides extra shaping gain for the LDPC-coded BICM-ID system. And our proposed method supplies better performance than conventional uniform mapping with the same spectrum efficiency.

scholarly journals Técnicas para la implementación de turbo decodificadores con baja latencia

2019 ◽  
pp. 29-41
Author(s):  
Lennin Conrado Yllescas-Calderon ◽  
Ramón Parra-Michel ◽  
Luis F Gonzalez-Pérez
Keyword(s):  
Channel Coding ◽  
Iterative Decoding ◽  
Turbo Coding ◽  
Processing Capacity ◽  
Turbo Decoding ◽  
Turbo Decoder ◽  
Transmission Rates ◽  
Communications Systems ◽  
Lte Advanced ◽  
Turbo Decoders

Turbo coding is a channel coding technique that increases the capacity of communications systems, especially wireless and mobile. Due to its high correction capability, this technique is used in modern wireless communication standards such as 3GPP and LTE/LTE-Advanced. One of the features of these systems is the increase in data processing capacity, where transmission rates of up to 1 Gbps are specified. However, the turbo coding technique inherently presents a limited performance as a consequence of the turbo decoding process at the reception stage. The turbo decoder presents a high operation latency mainly caused by the iterative decoding process, the interleaver and deinterleaver stage and the estimation process of the information bits. In this work, we show the techniques used to implement modern low-latency turbo decoders suitable for 3G and 4G standards.

scholarly journals Sparse Signature Matrix Optimization for NOMA under Imperfect CSI

2021 ◽  
Author(s):  
Kun Lu ◽  
Hongwen Yang
Keyword(s):  
Iterative Decoding ◽  
Information Transfer ◽  
Multiple Access ◽  
Rapid Development ◽  
Minimum Mean Square Error ◽  
Accurate Information ◽  
Analysis Tool ◽  
Matrix Optimization ◽  
High Spectral Efficiency ◽  
Signature Matrix

Abstract Non-orthogonal multiple access (NOMA) can support the rapid development of the Internet of Things (IoT) with its potential to support high spectral efficiency and massive connectivity. The low-density superposition modulation (LDSM) scheme is one of the NOMA schemes and uses the sparse signature matrix to reduce multiple access interferences (MAI). In order to improve the NOMA system performance in practice, this paper focuses on designing the sparse signature matrix with a large girth for LDSM under imperfect channel state information (CSI). Based on the orthogonal pilot and linear minimum mean square error (LMMSE) estimation, the LDSM optimized by bare-bone particle swarm optimization (BBPSO) algorithm has a larger girth and can gather more accurate information in the process of iterative decoding convergence. An extrinsic information transfer (EXIT) chart analysis is designed for the LDSM-OFDM system as a theoretical analysis tool. The simulation results show that the optimized LDSM outperforms the reference LDSM system, bringing about a 0.5 dB performance gain.

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