Thursday, October 22, 1998
4:30 - 5:30 PM
1311 EECS
Abstract-
When transmitting data symbols produced by some source over a
channel that makes insertion, deletion and substitution
errors, the source data must be encoded in such a way as to
enable the receiver to recover synchronization quickly after
an error. In many applications, it is also necessary to
determine the time index of each decoded symbol, i.e., its
position in the source sequence. This timing information
can then be used to determine exactly how much data has been
lost due to errors, or how much spurious data has been
created by the channel. Therefore, for such applications,
the code must enable the receiver to produce a sequence of
pairs, each pair consisting of a data symbol and a time
index, while keeping to a minimum the delay in recovering
synchronization and timing after an error. The performance
measures of rate, delay and amount of timing information are
used to characterize the performance of such codes. Here,
we introduce the class of periodic prefix-synchronized (PPS)
codes which can be used to provide synchronization with
timing information. PPS codes are binary block codes whose
codewords contain synchronizing markers at regular
intervals. The tradeoffs between rate, delay and timing
information are studied for these codes, and bounds to the
region of achievable performance are determined.
To link to Navin Kashyap's Home Page just click here