Passive system and method for measuring and monitoring the quality of service in a communications network

• US 20040034492A1
• Filed: 08/12/2003
• Published: 02/19/2004
• Est. Priority Date: 03/30/2001
• Status: Active Grant

• Current Assignee: Verizon Patent and Licensing Incorporated (Verizon Communications Inc.)
• Original Assignee: Level 3 Communications LLC (Lumen Technologies, Inc.)
• Inventors: Conway, Adrian E.
• Granted Patent: US 7,376,132 B2
• Time in Patent Office: Days
• US Class Current: 702/81
• CPC Class Codes: H04L 43/0829 Packet loss
• CPC Class Codes: H04L 43/0864 Round trip delays
• CPC Class Codes: H04L 43/087 Jitter
• CPC Class Codes: H04L 43/14 using software, i.e. software packages network security related monitoring H04L63/1408
• CPC Class Codes: H04L 43/16 Threshold monitoring

Abstract

In accordance with the present invention, a portion of a received media stream is copied from a data network without interfering with the flow of the data in the network. A known test signal is then substituted for the information contained in the copied portion of the media stream to prepare a pseudo-media stream. The known test signal is encoded, and packetized if necessary, using the same methods used for the received media stream. A pseudo-media signal is then recovered from the pseudo-media stream using the same depacketizing and decoding methods to be used on the received media stream. The recovered signal is an accurate representation of the state of the received media stream since it has gone through the same packetization/depacketization and encoding/decoding procedures, and it includes all of the same faults of the copied media stream. The perceptual quality of the recovered signal is then measured, providing an accurate measure of the perceptual quality of the copied media stream. The method may be applied to packetized as well as non-packetized voice signals.

Claims

1. A method for determining perceptual quality of a received encoded framed signal, comprising the following steps:

copying said received encoded framed signal to obtain a copied encoded framed signal;

replacing content of said copied encoded framed signal with content of a known encoded framed signal to produce a pseudo-encoded framed signal;

determining a perceptual quality of said pseudo-encoded framed signal; and

using said perceptual quality of said pseudo-encoded framed signal to generate a perceptual quality of said received encoded framed signal.

2. The method of claim 1, further comprising the step of encoding said known encoded framed signal with an encoding technique used for encoding said received framed encoded signal.

3. The method of claim 1, further comprising the step of framing said known encoded framed signal with a framing technique used for framing said received framed encoded signal.

4. The method of claim 1, further comprising the step of marking a frame in said copied encoded framed signal as corrupt in correspondence with a designated corrupt frame in said received framed encoded signal.

5. The method of claim 1, further comprising the step of decoding said pseudo-encoded framed signal with a decoding algorithm used for decoding said received encoded framed signal to produce a pseudo-decoded signal and a known decoded signal.

6. The method of claim 1, wherein the step of determining the perceptual quality of said pseudo-encoded framed signal comprises presenting said pseudo-decoded signal and said known decoded signal to an objective perceptual quality measurement tool.

7. The method of claim 6, wherein said objective perceptual quality measurement tool is the ITU-T Recommendation P.861.

8. The method of claim 6, wherein said objective perceptual quality measurement tool is the ITU-T Recommendation P.862.

9. The method of claim 1, wherein said known encoded framed signal comprises a pre-recorded voice signal.

10. The method of claim 1, wherein said known encoded framed signal comprises an artificial voice signal.

11. The method of claim 1, wherein said known encoded framed signal comprises a proprietary signal exhibiting natural speech characteristics.

12. The method of claim 1, further comprising the steps of:

identifying a frame in said received encoded framed signal that has been corrupted to produce a record of corrupted frames; and

transmitting said record to a server.

13. The method of claim 12, further comprising the step of transmitting a codec type to said server.

14. The method of claim 12, further comprising the step of transmitting a frame size to said server.

15. The method of claim 12, further comprising the step of converting said record to a compressed format prior to said step of transmitting said record to said server.

16. A system for determining perceptual quality of a received encoded framed signal, comprising:

means for copying said received encoded framed signal to obtain a copied encoded framed signal;

means for replacing content of said copied encoded framed signal with content of a known encoded framed signal to produce a pseudo-encoded framed signal;

means for determining a perceptual quality of said pseudo-encoded framed signal; and

means for generating a perceptual quality of said received encoded framed signal based on said perceptual quality of said pseudo-encoded framed signal.

17. The system of claim 16, further comprising means for encoding said known encoded framed signal with an encoding technique used for encoding said received framed encoded signal.

18. The system of claim 16, further comprising means for framing said known encoded framed signal with a framing technique used for framing said received framed encoded signal.

19. The system of claim 16, further comprising means for marking a frame in said copied encoded framed signal as corrupt in correspondence with a designated corrupt frame in said received framed encoded signal.

20. The system of claim 16, further comprising means for decoding said pseudo-encoded framed signal with a decoding algorithm used for decoding said received encoded framed signal to produce a pseudo-decoded signal and a known decoded signal.

21. The system of claim 16, wherein said means for determining the perceptual quality of said pseudo-encoded framed signal comprises an objective perceptual quality measurement tool.

22. The system of claim 21, wherein said objective perceptual quality measurement tool is the ITU-T Recommendation P.861.

23. The system of claim 21, wherein said objective perceptual quality measurement tool is the ITU-T Recommendation P.862.

24. The system of claim 16, wherein said known encoded framed signal comprises a pre-recorded voice signal.

25. The system of claim 16, wherein said known encoded framed signal comprises an artificial voice signal.

26. The system of claim 16, wherein said known encoded framed signal comprises a proprietary signal exhibiting natural speech characteristics.

27. The system of claim 16, further comprising:

means for identifying a frame in said received encoded framed signal that has been corrupted to produce a record of corrupted frames; and

means for transmitting said record to a server.

28. The system of claim 27, further comprising means for transmitting a codec type to said server.

29. The system of claim 27, further comprising means for transmitting a frame size to said server.

30. The system of claim 27, further comprising means for converting said record to a compressed format.

31. A method for determining perceptual quality of a received encoded framed signal, comprising the following steps:

identifying one or more corrupt frames in said received encoded framed signal to obtain a record of corrupt frames;

marking a set of frames in a known encoded framed signal in accordance with said record of corrupt frames to produce a pseudo-encoded framed signal;

determining a perceptual quality of said pseudo-encoded framed signal; and

using said perceptual quality of said pseudo-encoded framed signal to generate a perceptual quality of said received encoded framed signal.

32. The method for determining the perceptual quality of the received encoded framed signal of claim 31, further comprising the step of encoding said known encoded framed signal with an encoding technique used for encoding said received framed encoded signal.

33. The method for determining the perceptual quality of the received framed encoded signal of claim 31, further comprising the step of framing said known encoded framed signal with a framing technique used for framing said received framed encoded signal.

34. The method for determining the perceptual quality of the received framed encoded signal of claim 31, further comprising the step of marking a frame in said copied encoded framed signal as corrupt in correspondence with a designated corrupt frame in said received framed encoded signal.

35. The method for determining the perceptual quality of the received encoded framed signal of claim 31, further comprising the step of decoding said pseudo-encoded framed signal with a decoding algorithm used for decoding said received encoded framed signal to produce a pseudo-decoded signal and a known decoded signal.

36. The method for determining the perceptual quality of the received framed encoded voice signal of claim 31, wherein the step of determining the perceptual quality of said pseudo-encoded framed signal comprises presenting said pseudo-decoded signal and said known decoded signal to an objective perceptual quality measurement tool.

37. The method for determining the perceptual quality of the received framed encoded signal of claim 36, wherein said objective perceptual quality measurement tool is the ITU-T Recommendation P.861.

38. The method for determining the perceptual quality of the received framed encoded signal of claim 36, wherein said objective perceptual quality measurement tool is the ITU-T Recommendation P.862.

39. The method for determining the perceptual quality of the received framed encoded signal of claim 31, wherein said known encoded framed signal comprises a prerecorded voice signal.

40. The method for determining the perceptual quality of the received encoded framed signal of claim 31, wherein said known encoded framed signal comprises an artificial voice signal.

41. The method for determining the perceptual quality of the received framed encoded voice signal of claim 31, wherein said known encoded framed signal comprises a proprietary signal exhibiting natural speech characteristics.

42. The method for determining the perceptual quality of the received framed encoded voice signal of claim 31, further comprising the steps of:

identifying a frame in said received encoded framed signal that has been corrupted to produce a record of corrupted frames; and

transmitting said record to a server.

43. The method for determining the perceptual quality of the received framed encoded voice signal of claim 42, further comprising the step of transmitting a codec type to said server.

44. The method for determining the perceptual quality of the received framed encoded voice signal of claim 42, further comprising the step of transmitting a frame size to said server.

45. The method for determining the perceptual quality of the received framed encoded voice signal of claim 42, further comprising the step of converting said record to a compressed format prior to said step of transmitting said record to said server.

46. A system for determining perceptual quality of a received encoded framed signal, comprising:

means for identifying one or more corrupt frames in said received encoded framed signal to obtain a record of corrupt frames;

means for marking a set of frames in a known encoded framed signal in accordance with said record of corrupt frames to produce a pseudo-encoded framed signal;

means for determining a perceptual quality of said pseudo-encoded framed signal; and

means for generating a perceptual quality of said received encoded framed signal based on said perceptual quality of said pseudo-encoded framed signal.

47. A system for determining perceptual quality of a received encoded framed signal, comprising:

a data communications network;

a server; and

a client device, coupled to said server via said data communications network;

wherein said client device is configured to identify one or more corrupt frames in said received encoded framed signal to obtain a record of corrupt frames, and to transmit said record of corrupt frames to said server via said data communications network; and

wherein said server is configured

to mark a set of frames in a known encoded framed signal in accordance with said record of corrupt frames to produce a pseudo-encoded framed signal,

to determine a perceptual quality of said pseudo-encoded framed signal, and

to generate a perceptual quality for said received encoded framed signal based on said perceptual quality of said pseudo-encoded framed signal.

48. The system for determining the perceptual quality of the received encoded framed signal of claim 47, further comprising an encoder configured to encode said known encoded framed signal according to an encoding technique used for encoding said received framed encoded signal.

49. The system for determining the perceptual quality of the received framed encoded signal of claim 47, further comprising a frame generator configured to frame said known encoded framed signal according to a framing technique used for framing said received framed encoded signal.

50. The system for determining the perceptual quality of the received encoded framed signal of claim 47, further comprising means for decoding said pseudo-encoded framed signal according to a decoding algorithm used for decoding said received encoded framed signal to produce a pseudo-decoded signal.

51. The system for determining the perceptual quality of the received framed encoded voice signal of claim 47, further comprising an objective perceptual quality measurement tool configured to generate an objective quality value.

52. The system for determining the perceptual quality of the received framed encoded signal of claim 51, wherein said objective perceptual quality measurement tool is the ITU-T Recommendation P.861.

53. The system for determining the perceptual quality of the received framed encoded signal of claim 51, wherein said objective perceptual quality measurement tool is the ITU-T Recommendation P.862.

54. The system for determining the perceptual quality of the received framed encoded signal of claim 47, wherein said known encoded framed signal comprises a prerecorded voice signal.

55. The system for determining the perceptual quality of the received encoded framed signal of claim 47, wherein said known encoded framed signal comprises a P.50 artificial voice signal.

56. The system for determining the perceptual quality of the received framed encoded voice signal of claim 47, wherein said known encoded framed signal comprises a pre-recorded voice signal.

57. The system for determining the perceptual quality of the received framed encoded voice signal of claim 47, wherein said client device is further configured to transmit a codec type to said server.

58. The system for determining the perceptual quality of the received framed encoded voice signal of claim 47, wherein the client device is further configured to transmit a frame size to said server.

59. The system for determining the perceptual quality of the received framed encoded voice signal of claim 47, wherein said client device is further configured to convert said record to a compressed format prior to transmitting said record to said server.

60. The system for determining the perceptual quality of the received framed encoded signal of claim 47, further comprising an agent, coupled to said data communications network, configured to receive said record from said client device and to transmit said record to said server.