Does 16-QAM Provide an Alternative to a Half-Rate GSM Speech Codec?


Webb, W T, Hanzo, L, Salammi, R and Steele, R (1991) Does 16-QAM Provide an Alternative to a Half-Rate GSM Speech Codec? In, IEEE VTC'91, St. Louis, Miisouri, USA, 19 - 22 May 1991. , 511-516.

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Description/Abstract

The computational complexity, speech-quality, spectral efficiency and robustness trade-offs of speech transmission schemes for personal communications networks (PCNs) are addressed. Differentially encoded star 16-QAM arrangements with and without oversampling and diversity are compared in terms of robustness to the parallel frequency division multiplex (FDM) 16-QAM system to find the most appropriate modern scheme. The 13.4 <i>kbps</i> regular pulse <i>RPE-LTP</i> speech codec is subjected to rigorous bit sensitivity analysis in terms of both cepstral distance (CD) and segmental signal to ratio (SEGSNR) degradations. A twin-class embedded binary Bose-Chaudhuri-Hocqunghem (BCH) bit protection scheme is devised to improve robustness. The 6.2 kBd system proposed guarantees low-complexity, high-quality speech transmissions in a bandwidth of 12 kHz for vehicular speeds of 30 mph and channel signal to ratios (SNRs) in excess of 25 dB, a value readily maintained in microcellular PCNs. Wehn using diversity, our system has similar robustness to the 11.4 kbps quadruple-complexity, lower speech-quality code excited linear predictive speech codec/convolutional coding/minimum shift keying (CELP/CC/MSK) benchmarker utilised. Yes, 16-QAM does provide an attractive alternative to half-rate speech coding.

Item Type: Conference or Workshop Item (Paper)
Additional Information: Event Dates: 19-22 May 1991 Organisation: IEEE Address: St. Louis, Missouri, USA
Divisions: Faculty of Physical Sciences and Engineering > Electronics and Computer Science > Comms, Signal Processing & Control
ePrint ID: 251397
Date Deposited: 14 Sep 2001
Last Modified: 27 Mar 2014 19:52
Further Information:Google Scholar
URI: http://eprints.soton.ac.uk/id/eprint/251397

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