Subband speech coding and matched convolutional channel coding for mobile radio channels

Author

Cox, Richard V. ; Hagenauer, Joachim ; Seshadri, Nambirajan ; Sundberg, Carl-Erik W.

Author_Institution

AT&T Bell Labs., Murray Hill, NJ, USA

Volume

39

Issue

8

fYear

1991

fDate

8/1/1991 12:00:00 AM

Firstpage

1717

Lastpage

1731

Abstract

The effects of digital transmission errors on a family of variable-rate embedded subband speech coders (SBC) are analyzed in detail. It is shown that there is a difference in error sensitivity of four orders of magnitude between the most and the least sensitive bits of the speech coder. As a result, a family of rate-compatible punctured convolutional codes with flexible unequal error protection capabilities have been matched to the speech coder. These codes are optimally decoded with the Viterbi algorithm. Among the results, analysis and informal listening tests show that with a 4-level unequal error protection scheme transmission of 12 kb/s speech is possible with very little degradation in quality over a 16 kb/s channel with an average bit error rate (BER) of 2×10^-2 at a vehicle speed of 60 m.p.h. and with interleaving over two 16 ms speech frames

Keywords

coding errors; encoding; mobile radio systems; speech analysis and processing; telecommunication channels; 12 kbit/s; 16 kbit/s; Viterbi algorithm; decoding; error sensitivity; informal listening tests; interleaving; matched convolutional channel coding; mobile radio channels; rate-compatible punctured convolutional codes; subband speech coding; unequal error protection capabilities; variable-rate embedded subband speech coders; Bit error rate; Channel coding; Convolutional codes; Decoding; Degradation; Error correction codes; Speech analysis; Speech coding; Testing; Viterbi algorithm;

fLanguage

English

Journal_Title

Signal Processing, IEEE Transactions on

Publisher

ieee

ISSN

1053-587X

Type

jour

DOI

10.1109/78.91143

Filename

91143