Performance Enhancement of SOVA Based Decoder in SCCC and PCCC Schemes

作     者：Ahmed A. Hamad 

作者机构：Department of Electrical Engineering University of Babylon Babel Iraq 

出 版 物：《Wireless Engineering and Technology》 (无线工程与技术（英文）)

年 卷 期：2013年第4卷第1期

页      面：40-45页

学科分类：0810[工学-信息与通信工程] 08[工学] 081001[工学-通信与信息系统] 

主　　题：Turbo Codes SOVA SCCC Scaling Factor EXIT 

摘      要：This study proposes a simple scaling factor approach to improve the performance of parallel-concatenated convolutional code (PCCC) and serial concatenated convolutional code (SCCC) systems based on suboptimal soft-input soft-output (SISO) decoders. Fixed and adaptive scaling factors were estimated to mitigate both the optimistic nature of a posteriori information and the correlation between intrinsic and extrinsic information produced by soft-output Viterbi (SOVA) decoders. The scaling factors could be computed off-line to reduce processing time and implementation complexity. The simulation results show a significant improvement in terms of bit-error rate (BER) over additive white Gaussian noise and Rayleigh fading channel. The convergence properties of the suggested iterative scheme are assessed using the extrinsic information transfer (EXIT) chart analysis technique.