Turbo equalization scheme for intersymbol interference channels

• Main Author: Li, Yong
• Other Authors: Mow, Wai Ho
• Format: Theses and Dissertations
• Language: English
• Published: 2008
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Electronic circuits
• Online Access: http://hdl.handle.net/10356/13339
• Institution: Nanyang Technological University

In this thesis we try to find some effective equalization schemes for the receivers in digital communications, and investigate their performance over multipath channels with Intersymbol Interference (ISI). An interesting approach is introduced as Turbo Equalization, which jointly performs the equalization and channel decoding in a whole iterative process, with extrinsic information exchanged between each other. Based on this principle, more complicated channel codes, such as Turbo code (PCCC), serial concatenated convolutional code (SCCC) and hybrid concatenated convolutional code (HCCC) are integrated into the Turbo Equalization scheme to mitigate the ISI more effectively. Simulations are performed by applying these proposed schemes to the timevariant and time-invariant multipath fading channels. The results obtained show that in general Turbo Equalization is a more effective ISI-cancellation method than the conventional separately performed equalization and decoding, no matter they provide hard or soft outputs. Furthermore, our improved Turbo Equalization which employ PCCC SCCC or HCCC can achieve better error-correction performance than the original method using single convolutional code. For the purpose of theoretical analysis and comparison, an upper bound is derived to indicate their approaching performance correspondingly.