scholarly journals EXIT Chart Aided Design of DS-CDMA UltraWideBand Systems Using Iterative Decoding

Author(s):  
R. A. Riaz ◽  
M. El-Hajjar ◽  
Q. Z. Ahmed ◽  
S. X. Ng ◽  
S. Chen ◽  
...  
Author(s):  
Izabella Lokshina

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.


2011 ◽  
Vol 8 (18) ◽  
pp. 1486-1491
Author(s):  
Raja Ali Riaz ◽  
Ghufran Shafiq ◽  
Hamid Zaib ◽  
Bilal Tariq Malik ◽  
Saeed Ahmad

Author(s):  
Izabella Lokshina

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.


Author(s):  
Ahmed Haffane ◽  
Abdelhafid Hasni ◽  
Mustapha Khelifi ◽  
Boufeldja Kadri

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.


2008 ◽  
Vol 13 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Feng-kui Gong ◽  
Jian-hua Ge ◽  
Bing-bing Li

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