7th International Conference on Spoken Language Processing September 16-20, 2002 Denver, Colorado, USA

Network-Based vs. Distributed Speech Recognition in Adaptive Multi-Rate Wireless Systems

Tim Fingscheidt, Stefanie Aalburg, Sorel Stan, Christophe Beaugeant

Siemens AG, Germany

Distributed speech recognition (DSR) is motivated by the fact that codecs used in speech transmission usually reveal a degrading voice quality below some channel quality (carrier-to-interferer ratio C/I), which justifies efficient coding of features with an appropriate channel coding in the mobile terminal. The Adaptive Multi-Rate (AMR) speech codec standardized for GSM and UMTS however delivers an acceptable speech quality way down to C/I ratios of about 4 dB in the GSM full-rate speech channel.

In this paper we investigate network-based speech recognition (NSR) using a conventional speech channel with AMR coding as an alternative to a DSR system. This approach is natural and attractive since information services usually require a duplex channel for conversation anyway, furthermore no change to existing mobiles is required. For a GSM full-rate channel it turns out that an NSR system based on AMR coding indeed is comparable to DSR approaches.

Full Paper

Bibliographic reference.  Fingscheidt, Tim / Aalburg, Stefanie / Stan, Sorel / Beaugeant, Christophe (2002): "Network-based vs. distributed speech recognition in adaptive multi-rate wireless systems", In ICSLP-2002, 2209-2212.