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Summary: 570 IEEE TRANSACTIONS ON SPEECH AND AUDIO PROCESSING, VOL. 10, NO. 8, NOVEMBER 2002
Low-Bitrate Distributed Speech Recognition for
Packet-Based and Wireless Communication
Alexis Bernard, Student Member, IEEE, and Abeer Alwan, Senior Member, IEEE
Abstract--In this paper, we present a framework for developing
source coding, channel coding and decoding as well as erasure con-
cealment techniques adapted for distributed (wireless or packet-
based) speech recognition. It is shown that speech recognition as
opposed to speech coding, is more sensitive to channel errors than
channel erasures, and appropriate channel coding design criteria
are determined. For channel decoding, we introduce a novel tech-
nique for combining at the receiver soft decision decoding with
error detection. Frame erasure concealment techniques are used
at the decoder to deal with unreliable frames. At the recognition
stage, we present a technique to modify the recognition engine itself
to take into account the time-varying reliability of the decoded fea-
ture after channel transmission. The resulting engine, referred to
as weighted Viterbi recognition, further improves recognition ac-
curacy. Together, source coding, channel coding and the modified
recognition engine are shown to provide good recognition accuracy
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