Evaluation of Variance Mismatch of Serial Turbo Codes 359
Journal of Engineering Science and Technology September 2010, Vol. 5(3)
The issue of variance mismatch on the performance of serial turbo codes (SCCC)
using the log-MAP and max-log-MAP constituent decoders was investigated in
impulsive noise channel. The log-MAP algorithm requires knowledge of the
channel reliability for the metric calculation, whereas the max-log-MAP
algorithm obviates this side information as a result of using an approximation.
However, both traditionally designed algorithms failed to perform in impulse
noise interference. Therefore, talwar penalty function was introduced and reported
to effectively curb against outliers of impulse noise reported in . By setting
appropriate value for cutoff parameter v, the entries of undesired outliers from
impulse noise is blocked and cut off prior to the computation of channel transition
(s΄, s). Therefore, LOG-MAP and MAX-LOG-MAP algorithms of
SCCC can be used in determine extrinsic information L
for inner and outer
As for the increasing importance of using PLC for internet and information
sharing , the study of variance mismatch for SCCC in impulsive noise
channel for next generation communication system is crucial to the researchers
and engineers in the field. Talwar penalty function enables and extends the
excellent performance of MAP based SCCC to a new technology frontier.
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