Summary: Impact of Soft Channel Construction on
Iterative Channel Estimation and Data Decoding
for Multicarrier Systems
, Alexei Ashikhmin
, Jiunn-Tsair Chen
Institute of Commun. Engr.
Math. of Communications Research Dep.
National Tsing Hua University Bell Lab., Alcatel-Lucent Tech.
Hsinchu, Taiwan 30055, R.O.C. Murray Hill, NJ 07974, U.S.A.
July 26, 2007
To apply the promising idea of iterative information processing to the problem of joint chan-
nel estimation and data decoding, one may utilize the soft information of the coded bits to
help refine the channel estimate, e.g., with Wiener filtering. However, the performance of
such an iterative approach depends on not only the construction of the iteratively refined
soft channel, but also the structure of the adopted error-correction code. Through extrinsic
information transfer chart analysis, we investigate the impact of different soft channel con-
struction schemes on multicarrier systems possessing turbo coding/modulation structures:
(1) one with bit-interleaved coded modulation signals, and (2) the other with low-density