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Wideband speech and audio compression for wireless communications

Wideband speech and audio compression for wireless communications
Wideband speech and audio compression for wireless communications

This thesis is based on research into wideband speech and audio compression. We have studied the Code-Excited Linear Predictive (CELP) codecs, which use forward adaptation of the linear prediction synthesis filter, as well as codecs which use backward adaptation. A subband-split coding technique has been investigated where the high frequency, low energy subband has been treated separately with its bit rate contribution limited appropriately. A codec utilising a fullband forward adaptive coding approach has also been investigated. A range of wideband Line Spectrum Frequency (LSF) Vector Quantization (VQ) schemes designed for this codec have been comparatively studied.

In addition, backward adaptive linear prediction analysis offers a solution for maintaining a low coding delay, namely below 10 ms. A low delay wideband speech codec, operating at a variable bit rate ranging from 32 down to 8 kbit/s has been studied, which was obtained from the extension of the G.728 16 kbit/s low delay narrowband standard codec. A low delay wideband codec utilising the algebraic CELP (ACELP) technique has also been investigated.

The new GSM Adaptive Multi-Rate (AMR) codec has been studied and its corresponding bits sensitivities were characterized. A burst-by-burst (BbB) adaptive Joint-Detection based Code-Division Multiple Access (JD-CDMA) speech transceiver has been developed, which is capable of dropping its source coding rate from 10.2 kbit/s to 4.75 kbit/s at a concomitant reduction of its speech quality under transceiver control in order to invoke a more error resilient modem mode amongst less favourable channel conditions. Both the objective and subjective speech quality assessments favoured the proposed BbB adaptive transceiver.

University of Southampton
How, Hee Thong
2f5abd45-c7b2-4d02-9a88-0cd11030f508
How, Hee Thong
2f5abd45-c7b2-4d02-9a88-0cd11030f508

How, Hee Thong (2001) Wideband speech and audio compression for wireless communications. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

This thesis is based on research into wideband speech and audio compression. We have studied the Code-Excited Linear Predictive (CELP) codecs, which use forward adaptation of the linear prediction synthesis filter, as well as codecs which use backward adaptation. A subband-split coding technique has been investigated where the high frequency, low energy subband has been treated separately with its bit rate contribution limited appropriately. A codec utilising a fullband forward adaptive coding approach has also been investigated. A range of wideband Line Spectrum Frequency (LSF) Vector Quantization (VQ) schemes designed for this codec have been comparatively studied.

In addition, backward adaptive linear prediction analysis offers a solution for maintaining a low coding delay, namely below 10 ms. A low delay wideband speech codec, operating at a variable bit rate ranging from 32 down to 8 kbit/s has been studied, which was obtained from the extension of the G.728 16 kbit/s low delay narrowband standard codec. A low delay wideband codec utilising the algebraic CELP (ACELP) technique has also been investigated.

The new GSM Adaptive Multi-Rate (AMR) codec has been studied and its corresponding bits sensitivities were characterized. A burst-by-burst (BbB) adaptive Joint-Detection based Code-Division Multiple Access (JD-CDMA) speech transceiver has been developed, which is capable of dropping its source coding rate from 10.2 kbit/s to 4.75 kbit/s at a concomitant reduction of its speech quality under transceiver control in order to invoke a more error resilient modem mode amongst less favourable channel conditions. Both the objective and subjective speech quality assessments favoured the proposed BbB adaptive transceiver.

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Published date: 2001

Identifiers

Local EPrints ID: 464373
URI: http://eprints.soton.ac.uk/id/eprint/464373
PURE UUID: b4970f51-5e89-425f-9afa-5eb8f49eb037

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Date deposited: 04 Jul 2022 22:21
Last modified: 16 Mar 2024 19:27

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Author: Hee Thong How

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