System and method for enhanced artificial bandwidth expansion

1. A method for expanding narrowband speech signals to wideband speech signals, the method comprising:

determining signal type information from a signal;

obtaining characteristics for forming an upper band signal using the determined signal type information;

detecting babble noise in the signal based on a gradient index, enemy information, and a noise level estimate;

determining signal noise information, wherein the signal noise information is determined based on a far-end signal-to-noise ratio and a near-end signal-to-noise ratio;

using the determined signal noise information to modify the obtained characteristics for forming the upper band signal; and

forming the upper band signal using the modified characteristics.

2. The method claim 1 , wherein the determining of the signal noise information comprises estimating the far-end signal-to-noise ratio using information on energy of a portion of the signal and a background noise level estimate.

3. The method of claim 2 , wherein the determining of the signal noise information comprises estimating the near-end signal-to-noise ratio.

4. The method of claim 1 , further comprising classifying the signal into different phoneme groups based on the gradient index and the far-end signal-to-noise ratio.

5. A communication device configured to receive wideband signals, the device comprising:

an interface that communicates with a wireless network; and

programmed instructions stored in a memory and configured to expand received narrowband signals to wideband signals by adjusting an artificial bandwidth expansion algorithm based on noise conditions, wherein the noise conditions comprise a far-end signal-to-noise ratio and a near-end signal-to-noise ratio; and

detect babble noise based on a gradient index, energy information, and a noise level estimate.

6. The device of claim 5 , wherein the programmed instructions are implemented with a digital signal processor (DSP).

7. A device in a communication network that expands narrowband speech signals into wideband speech signals, the device comprising:

a narrowband codec that receives narrowband speech signals in a network;

a wideband codec that communicates wideband speech signals to wideband terminals in communication with the network; and

programmed instructions that expand the narrowband speech signals to wideband speech signals by adjusting an artificial bandwidth expansion algorithm based on noise conditions, wherein the noise conditions comprise a far-end signal-to-noise ratio and a near-end signal-to-noise ratio and detect babble noise based on a gradient index, energy information, and a noise level estimate.

8. A system for expanding narrowband speech signals to wideband speech signals, the system comprising:

means for determining signal type information from a signal;

means for obtaining characteristics for forming an upper band signal using the determined signal type information;

means for detecting babble noise based on a gradient index, energy information, and a noise level estimate

means for determining signal noise information, wherein the signal noise information is determined based on a far-end signal-to-noise ratio and a near-end signal-to-noise ratio;

means for using the determined signal noise information to modify the obtained characteristics for forming the upper band signal; and

means for forming the upper band signal using the modified characteristics.

9. A computer program product, embodied in a computer-readable medium, that expands narrowband speech signals to wideband speech signals, the computer program product comprising:

computer code to:

determine signal type information from a signal;

obtain characteristics for forming an upper band signal using the determined signal type information;

detect babble noise based on a gradient index, energy information, and a noise level estimate

determine signal noise information, wherein the signal noise information is determined based on a far-end signal-to-noise ratio and a near-end signal-to-noise ratio;

use the determined signal noise information to modify the obtained characteristics for forming the upper band signal; and

form the upper band signal using the modified characteristics.

10. The computer program product of claim 9 , wherein the computer code further expands the signal from a narrowband signal to a wideband signal based on signal gradient index, signal far-end signal-to-noise ratio, and signal near-end signal-to-noise ratio.

11. The computer program product of claim 9 , wherein the computer code further estimates a near-end signal-to-noise ratio.