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Summary: IEEE TRANSACTIONS ON COMMUNICATIONS, VOL. 50, NO. 2, FEBRUARY 2002 309
Speech Transmission Using Rate-Compatible Trellis
Codes and Embedded Source Coding
Alexis Bernard, Student Member, IEEE, Xueting Liu, Member, IEEE, Richard D. Wesel, Senior Member, IEEE,
and Abeer Alwan, Senior Member, IEEE
Abstract--This paper presents bandwidth-efficient speech
transmission systems using rate-compatible channel coders
and variable bitrate embedded source coders. Rate-compatible
punctured convolutional codes (RCPC) are often used to provide
unequal error protection (UEP) via progressive bit puncturing.
RCPC codes are well suited for constellations for which Euclidean
and Hamming distances are equivalent (BPSK and 4-PSK). This
paper introduces rate-compatible punctured trellis codes (RCPT)
where rate compatibility and UEP are provided via progressive
puncturing of symbols in a trellis. RCPT codes constitute a special
class of codes designed to maximize residual Euclidean distances
(RED) after symbol puncturing. They can be designed for any
constellation, allowing for higher throughput than when restricted
to using 4-PSK. We apply RCPC and RCPT to two embedded
source coders: a perceptual subband coder and the ITU embedded
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