Method and apparatus for non-intrusive single-ended voice quality assessment in VoIP

1. A method for voice quality estimation in a VoIP system, comprising:

detecting an impairment in a received VoIP signal having a series of packets, where an original signal corresponding the received VoIP signal is not available, wherein detecting the impairment further comprises,

calculating the average energy of each packet of the received VoIP signal;

determining an energy threshold value of silence for the received VoIP signal;

for every packing having an energy value less than the energy threshold value, replacing the energy value with the energy threshold value to produce a modified VoIP signal corresponding to the received VoIP signal;

calculating the inverse of the energy of the modified VoIP signal; and

identifying lost packets in the received VoIP signal by identifying peaks in the inverse of the energy of the modified VoIP signal;

evaluating an amount of degradation in the received VoIP signal caused by the impairment; and

estimating the voice quality of the received VoIP signal according to the amount of degradation.

2. A method for voice quality estimation in a VoIP system, comprising:

detecting an impairment in a received VoIP signal having a series of packets, where an original signal corresponding the received VoIP signal is not available, wherein detecting the impairment further comprises,

calculating the cross-correlation of each packet of the received VoIP signal and the previous packet of the received VoIP signal;

monitoring the value of cross-correlation with no shift of each packet of the received VoIP signal and the previous packet of the received VoIP signal; and

identifying a lost packet whenever the value of the cross-correlation with no shift exceeds a threshold;

evaluating an amount of degradation in the received VoIP signal caused by the impairment; and

estimating the voice quality of the received VoIP signal according to the amount of degradation.

3. The method of claim 1 , wherein evaluating an amount of degradation in the received VoIP signal further comprises:

estimating the original energy of at least one lost packet of the received VoIP signal;

calculating the percentage of the estimated lost energy to the total energy in the received VoIP signal;

determining the amount of degradation in the received VoIP signal according to the percentage of the estimated lost energy.

4. The method of claim 3 , wherein estimating the voice quality of the received VoIP signal further comprises subtracting a score corresponding to the amount of degradation of an ideal voice quality score to produce a degraded voice quality score.

5. A method for voice quality estimation in a VoIP system, comprising:

detecting an impairment in a received VoIP signal having a series of packets, where an original signal corresponding the received VoIP signal is not available, wherein detecting the impairment further comprises,

calculating the sum of the absolute amplitudes for each packet of the received VoIP signal;

selecting an initial threshold;

comparing each sum with the threshold;

for each sum that is less than the threshold, replacing the sum with the threshold to produce a modified signal;

if the sums of the modified signal are substantially the same as the sums of the received VoIP signal, then increasing the threshold and repeating the process from the comparing step; and

storing the threshold as a VAD threshold estimate;

evaluating an amount of degradation in the received VoIP signal caused by the impairment; and

estimating the voice quality of the received VoIP signal according to the amount of degradation.

6. A method for voice quality estimation in a VoIP system, comprising:

detecting an impairment in a received VoIP signal having a series of packets, where an original signal corresponding the received VoIP signal is not available;

evaluating an amount of degradation in the received VoIP signal caused by the impairment, wherein the evaluating an amount of degradation further comprises,

identifying the location of a plurality of silent replaced packets of the received VoIP signal;

classifying each of the plurality of the silent replaced packets as front-end clipping, middle-speech clipping, and back-end clipping;

calculating a voice quality score according to the percentage of packets of the received VoIP signal that are classified as each of front-end clipping, middle-speech clipping, and back-end clipping; and

estimating the voice quality of the received VoIP signal according to the amount of degradation.

7. A telecommunications apparatus, comprising:

a processor configured to receive a VoIP signal comprising a series of packets; and

a memory, accessible by the processor, the memory storing packet data corresponding to the series of packets, wherein the processor is configured to:

detect an impairment in the VoIP signal, where an original signal corresponding to VoIP signal is not available;

evaluate an amount of degradation in the VoIP signal caused by the impairment;

estimate the voice quality of the VoIP signal according to the amount of degradation; and

wherein the processor is further configured to:

calculate the average energy of each packet of the VoIP signal;

determine an energy threshold value of silence for the VoIP signal;

replace the energy value with the energy threshold value to produce a modified VoIP signal corresponding to the VoIP signal, for every packing having an energy value less than the energy threshold value;

calculate the inverse of the energy of the modified VoIP signal; and

identify lost packets in the VoIP signal by identifying peaks in the inverse of the energy of the modified VoIP signal.

8. A telecommunications apparatus, comprising:

a processor configured to receive a VoIP signal comprising a series of packets; and

a memory, accessible by the processor, the memory storing packet data corresponding to the series of packets, wherein the processor is configured to:

detect an impairment in the VoIP signal, where an original signal corresponding to VoIP signal is not available;

evaluate an amount of degradation in the VoIP signal caused by the impairment;

estimate the voice quality of the VoIP signal according to the amount of degradation; and

wherein the processor is further configured to:

calculate the cross-correlation of each packet of the VoIP signal and the previous packet of the VoIP signal;

monitor the value of cross-correlation with no shift of each packet of the VoIP signal and the previous packet of the VoIP signal; and

identifying a lost packet whenever the value of the cross-correlation with no shift exceeds a threshold.

9. The telecommunications apparatus of claim 7 , wherein the processor is further configured to:

estimate the original energy of at least one lost packet of the VoIP signal;

calculate the percentage of the estimated lost energy to the total energy in the VoIP signal;

determine the amount of degradation in the VoIP signal according to the percentage of the estimated lost energy.

10. The telecommunications apparatus of claim 9 , wherein the processor is further configured to subtract a score corresponding to the amount of degradation of an ideal voice quality score to produce a degraded voice quality score.

11. A telecommunications apparatus, comprising:

a processor configured to receive a VoIP signal comprising a series of packets; and

a memory, accessible by the processor, the memory storing packet data corresponding to the series of packets, wherein the processor is configured to:

detect an impairment in the VoIP signal, where an original signal corresponding to VoIP signal is not available;

evaluate an amount of degradation in the VoIP signal caused by the impairment;

estimate the voice quality of the VoIP signal according to the amount of degradation; and

wherein the processor is further configured to:

calculate the sum of the absolute amplitudes for each packet of the received VoIP signal;

select an initial threshold; compare each sum with the threshold;

for each sum that is less than the threshold, replace the sum with the threshold to produce a modified signal;

if the sums of the modified signal are substantially the same as the sums of the VoIP signal, then increase the threshold and repeating the process from the comparing step; and

store the threshold as a VAD threshold estimate.

12. A telecommunications apparatus, comprising:

a processor configured to receive a VoIP signal comprising a series of packets; and

a memory, accessible by the processor, the memory storing packet data corresponding to the series of packets, wherein the processor is configured to:

detect an impairment in the VoIP signal, where an original signal corresponding to VoIP signal is not available;

evaluate an amount of degradation in the VoIP signal caused by the impairment;

estimate the voice quality of the VoIP signal according to the amount of degradation; and

wherein the processor is further configured to:

identify the location of a plurality of silent replaced packets of the VoIP signal;

classify each of the plurality of the silent replaced packets as front-end clipping, middle-speech clipping, and back-end clipping;

calculate a voice quality score according to the percentage of packets of the VoIP signal that are classified as each of front-end clipping, middle-speech clipping, and back-end clipping.