Apparatus, methods and articles incorporating a fast algebraic codebook search technique

• US 7,249,014 B2
• Filed: 03/13/2003
• Issued: 07/24/2007
• Est. Priority Date: 03/13/2003
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Kannan, Karthik, Subramanian, Meenakshi Sundaram
• Primary Examiner(s): Hudspeth; David
• Assistant Examiner(s): ALBERTALLI, BRIAN LOUIS
• Application Number:
  US10/387,749
• Publication Number:
  US 20040181400A1
• Time in Patent Office: 1,594 Days
• Field of Search: 704/219, 704/220, 704/221, 704/223, 379/88.1
• US Class Current: 704/219
• CPC Class Codes: G10L 19/107 Sparse pulse excitation, e.g. by using algebraic codebook

Abstract

An efficient method for codebook search, employed in speech coding, uses an optimal pulse-position grouping and a split track arrangement, based on a likelihood estimator. Also disclosed are codecs, mobile voice communication devices, telecommunications equipment and telecommunications methods.

Claims

1. A method comprising conducting a random excitation codebook search in an Algebraic Code-Excited-Linear-Prediction (ACELP) codec, wherein the random excitation codebook search in the ACELP codec is conducted by grouping pulse positions based on relative importance of pulse positions as a function of an absolute value |b(n)| of a telecommunication signal b(n) and wherein pulse positions of at least one group are divided into at least two sub-groups corresponding to respective odd maximums and even maximums of the absolute value of the signal b(n).

2. A method according to claim 1 further including grouping pulse positions in sub-tracks.

3. A method according to claim 1 further including selecting a codebook vector from the codebook.

4. A method according to claim 1 further including grouping pulse positions based to provide grouping that is at least partially optimized for a codebook search.

5. A method according to claim 1 wherein pulse positions are grouped using the absolute magnitude of a signal b(n) as a prediction factor for determining the optimum grouping.

6. A method according to claim 1 wherein pulses are grouped in tracks.

7. A method according to claim 6 wherein pulses are grouped in sub-tracks.

8. A method comprising grouping pulse positions for the purpose of conducting a random excitation codebook search in an Algebraic Code-Excited-Linear-Prediction (ACELP) codec, wherein the pulse positions are grouped in a plurality of subtracks of number A and the pulse code combinations in a group is less than the number of pulse code combinations in the subtracks A if the pulse positions are grouped in a plurality of groups of number G wherein A is greater than G, and further wherein the pulses are grouped in the plurality of subtracks A according to an algorithm that increases the chances that a codebook search of the subtracks A will yield an optimum result that is better than if the pulses are arbitrarily grouped, wherein the algorithm includes grouping pulse positions corresponding to respective odd maximums and even maximums of an absolute value of a telecommunications signal b(n).

9. A method according to claim 8 further including selecting a codebook vector from the codebook.

10. A method comprising conducting a random excitation codebook search in an Algebraic Code-Excited-Linear-Prediction (ACELP) codec using one or more tracks of pulse positions, wherein at least one of the tracks is subdivided into at least two sub-tracks and pulse positions are grouped in the at least two sub-tracks corresponding to respective odd maximums and even maximums of the absolute value of a signal b(n).

11. A method according to claim 10 further wherein the grouping of pulses in the sub-tracks evenly distributes the contributions of pulse positions between the sub-tracks.

12. A method according to 10 further wherein the number of tracks is 5 and the number of sub-tracks is 2, and the number of pulse positions in each sub-track is 4.

13. A method comprising grouping pulse positions to increase the likelihood that a codebook search of the resulting combinations of pulse positions will yield an acceptable result, wherein the method is performed in an Algebraic Code-Excited-Linear-Prediction (ACELP) codec, wherein the pulse positions are grouped based on relative importance of pulse positions as a function of an absolute value |b(n)| of a telecommunication signal b(n), further wherein the pulse positions are grouped into at least two sub-groups corresponding to respective odd maximums and even maximums of the absolute value of the telecommunication signal b(n).

14. A method according to claim 13 further wherein an acceptable result is one that produces signal degradation that is not perceptual to a human listener.

15. A method according to claim 13 further wherein the grouping of pulse positions is determined according to an optimization algorithm.