A.2 Basic coder parameters

06.203GPPHalf rate speech transcodingTS

The following are the basic parameters for the 5 600 bps GSM half rate speech codec system.

sampling rate

8 kHz

NF

frame length

160 samples (20 ms)

Ns

subframe length

40 samples (5 ms)

Np

short term predictor order

10

Annex B (normative): Order of occurrence of the codec parameters over Abis

The order of occurrence of the codec parameters over the Abis is defined for unvoiced speech (MODE = 0) and voiced speech (MODE = 1, 2 or 3) in tables B.1 and B.2 respectively.

Table B.1: Occurrence of the codec parameters over Abis for unvoiced speech (MODE = 0)

Parameter

No. of bits

Bit No. (MSB – LSB)

R0

5

b1 – b5

LPC1

11

b6 – b16

LPC2

9

b17 – b25

LPC3

8

b26 – b33

INT_LPC

1

b34

MODE

2

b35 – b36

CODE1_1

7

b37 – b43

CODE2_1

7

b44 – b50

GSP0_1

5

b51 – b55

CODE1_2

7

b56 – b62

CODE2_2

7

b63 – b69

GSP0_2

5

b70 – b74

CODE1_3

7

b75 – b81

CODE2_3

7

b82 – b88

GSP0_3

5

b89 – b93

CODE1_4

7

b94 – b100

CODE2_4

7

b101 – b107

GSP0_4

5

b108 – b112

Table B.2: Occurrence of the codec parameters over Abis for voiced speech (MODE = 1, 2 or 3)

Parameter

No. of bits

Bit No. (MSB – LSB)

R0

5

b1 – b5

LPC1

11

b6 – b16

LPC2

9

b17 – b25

LPC3

8

b26 – b33

INT_LPC

1

b34

MODE

2

b35 – b36

LAG_1

8

b37 – b44

CODE1

9

b45 – b53

GSP0_1

5

b54 – b58

LAG_2

4

b59 – b62

CODE2

9

b63 – b71

GSP0_2

5

b72 – b76

LAG_3

4

b77 – b80

CODE3

9

b81 – b89

GSP0_3

5

b90 – b94

LAG_4

4

b95 – b98

CODE4

9

b99 – b107

GSP0_4

5

b108 – b112

Annex C (informative): Bibliography

M. R. Schroeder and B. S. Atal, "Code-Excited Linear Prediction (CELP): High Quality Speech at Very Low Bit Rates", Proc. IEEE Int. Conf. on Acoustics, Speech and Signal Processing, pp. 937‑940, March 1985.

G. Davidson and A. Gersho, "Complexity Reduction Methods for Vector Excitation Coding", Proc. IEEE Int. Conf. on Acoustics, Speech and Signal Processing, pp. 3055‑3058, April 1986.

I. Gerson and M. Jasiuk, "Vector Sum Excited Linear Prediction (VSELP) Speech Coding at 8 kbps", Proc. IEEE Int. Conf. on Acoustics, Speech and Signal Processing, pp. 461‑464, April 1990.

P. Kroon and B. S. Atal, "Pitch Predictors with High Temporal Resolution", Proc. IEEE Int. Conf. on Acoustics, Speech and Signal Processing, pp. 661‑664, April 1990.

I. A. Gerson, "Method and Means of Determining Coefficients for Linear Predictive Coding", U. S. Patent #4,544,919, Oct. 1985.

A. Cumani, "On a Covariance-Lattice Algorithm for Linear Prediction", Proc. IEEE Int. Conf. on Acoustics, Speech and Signal Processing, pp. 651‑654, May 1982.

M. McLaughlin, I. Gerson, F. Hudziak, and K. Kloker, "High Performance Processor for Real-Time Speech Applications", Proc. IEEE Int. Conf. on Acoustics, Speech and Signal Processing, pp. 859‑863, April 1980.

Y. Tohkura, F. Itakura and S. Hashimoto, "Spectral Smoothing Technique in PARCOR Speech Analysis-Synthesis", IEEE Trans. Acoustics, Speech and Signal Processing, vol. ASSP‑26, pp. 591‑596, Dec. 1978.

W. Kleijn, D. Krasinski, and R. Ketchum, "Improved Speech Quality and Efficient Vector Quantization in SELP", Proc. IEEE Int. Conf. on Acoustics, Speech and Signal Processing, pp. 155‑158, April 1988.

Y. Linde, A. Buzo, and R. M. Gray, "An Algorithm for Vector Quantizer Design", IEEE Trans. Comm., vol. COM‑28, pp. 84‑95, Jan. 1980.

Juin-Hwey Chen and Allen Gersho, "Real-Time Vector APC Speech Coding at 4800 bps with Adaptive Postfiltering", Proc. IEEE Int. Conf. on Acoustics, Speech and Signal Processing, pp. 2185‑2188, 1987.