Backward adaptive lattice and transversal predictors in low-delay CELP coders

Abstract This paper examines several backward lattice and transversal algorithms for updating the short-term prediction filter and the weighting filter in low-delay CELP (LD-CELP) systems operating at 16 kbit/s. We have considered block recursive adaptation structures and evaluated their relative merits both in terms of reconstructed speech quality and computational complexity. Comparisons in terms of performance are based on objective measures (signal-to-noise ratio, segmental signal-to-noise ratio and a frequency weighted signal-to-noise ratio) and on subjective results obtained from listening tests. Simulation results are presented and discussed for both ideal and noisy communication channels. Among the investigated adaptation schemes, the best performance in error-free channel was obtained with the exponential window lattice and the signal-driven lattice. However, a trade-off among robustness in noisy channels, performance under error-free conditions and computational complexity leads to the residual-driven lattice as an attractive algorithm to be used in LD-CELP structures.

[1]  T. Claasen,et al.  Comparison of the convergence of two algorithms for adaptive FIR digital filters , 1981 .

[2]  J. Melsa,et al.  The Residual Encoder - An Improved ADPCM System for Speech Digitization , 1975, IEEE Transactions on Communications.

[3]  Manfred R. Schroeder,et al.  Code-excited linear prediction(CELP): High-quality speech at very low bit rates , 1985, ICASSP '85. IEEE International Conference on Acoustics, Speech, and Signal Processing.

[4]  Jerry D. Gibson,et al.  A comparison of backward adaptive prediction algorithms in low delay speech coders , 1990, International Conference on Acoustics, Speech, and Signal Processing.

[5]  Jerry D. Gibson,et al.  Backward Adaptive Lattice and Transversal Predictors in ADPCM , 1985, IEEE Trans. Commun..

[6]  Nuggehally Sampath Jayant,et al.  Improving the performance of the 16 kb/s LD-CELP speech coder , 1992, [Proceedings] ICASSP-92: 1992 IEEE International Conference on Acoustics, Speech, and Signal Processing.

[7]  Allen Gersho,et al.  Adaptive filtering with binary reinforcement , 1984, IEEE Trans. Inf. Theory.

[8]  J.J. Shynk,et al.  Backward adaptation for low delay vector excitation coding of speech at 16 kbit/s , 1989, IEEE Global Telecommunications Conference, 1989, and Exhibition. 'Communications Technology for the 1990s and Beyond.

[9]  Paul Mermelstein,et al.  Ensuring predictor tracking in ADPCM speech coders under noisy transmission conditions , 1988, IEEE J. Sel. Areas Commun..

[10]  B. Friedlander,et al.  Lattice filters for adaptive processing , 1982, Proceedings of the IEEE.

[11]  Vladimir Cuperman,et al.  Low-delay analysis-by-synthesis speech coding using lattice predictors , 1990, [Proceedings] GLOBECOM '90: IEEE Global Telecommunications Conference and Exhibition.

[12]  V. Cuperman,et al.  Variable-rate low-delay analysis-by-synthesis speech coding at 8-16 kb/s , 1991, [Proceedings] ICASSP 91: 1991 International Conference on Acoustics, Speech, and Signal Processing.

[13]  Allen Gersho,et al.  Gain-Adaptive Vector Quantization with Application to Speech Coding , 1987, IEEE Trans. Commun..

[14]  Isabel Trancoso,et al.  Efficient procedures for finding the optimum innovation in stochastic coders , 1986, ICASSP '86. IEEE International Conference on Acoustics, Speech, and Signal Processing.

[15]  J. Makhoul.  A class of all-zero lattice digital filters: Properties and applications , 1978 .

[16]  Y.-C. Lin,et al.  A fixed-point 16 kb/s LD-CELP algorithm , 1991, [Proceedings] ICASSP 91: 1991 International Conference on Acoustics, Speech, and Signal Processing.

[17]  R. Gray,et al.  Product code vector quantizers for waveform and voice coding , 1984 .