A low complexity soft-input soft-output (SISO) block decision feedback equalizer (BDFE) is presented for turbo equalization. The proposed method employs a sub-optimum sequence-based detection, where the soft-output of the equalizer is calculated by evaluating an approximation of the sequence-based a posteriori probability (APP) of the data symbol. The sequence-based APP approximation is enabled by the adoption of both soft a priori information and soft decision feedback, and it leads to better performance and faster convergence compared to symbol-based detection methods as used by most other low complexity equalizers. The performance and convergence property of the proposed algorithm is analyzed by using extrinsic information transfer (EXIT) chart. Both analytical and simulation results show that the new equalizer can achieve a performance similar to that of trellis-based equalization algorithms, with a complexity similar to linear SISO minimum mean square error equalizers.
J. Wu and Y. R. Zheng, "Low Complexity Soft-Input Soft-Output Block Decision Feedback Equalization," IEEE Journal on Selected Areas in Communications, Institute of Electrical and Electronics Engineers (IEEE), Feb 2008.
The definitive version is available at http://dx.doi.org/10.1109/JSAC.2008.080205
Electrical and Computer Engineering
Keywords and Phrases
BDFE; EXIT; Sequence-Based Detection; Soft Decision Feedback; Turbo Equalization
Article - Journal
© 2008 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.