Media (voice) playback (de-jitter) buffer adjustments based on air interface

• US 8,085,678 B2
• Filed: 10/13/2004
• Issued: 12/27/2011
• Est. Priority Date: 10/13/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Spindola, Serafin Diaz, Black, Peter J.
• Primary Examiner(s): Sinkantarakorn, Pao
• Assistant Examiner(s): PATEL, CHANDRAHAS B
• Application Number:
  US10/964,319
• Publication Number:
  US 20060077994A1
• Time in Patent Office: 2,631 Days
• Field of Search: 370/235, 370/252, 370/412, 370/516, 370/519
• US Class Current: 370/252
• CPC Class Codes: H04J 3/0632 Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56
• CPC Class Codes: H04L 1/205 jitter monitoring
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04W 28/14 using intermediate storage
• CPC Class Codes: H04W 36/00 Hand-off or reselection arrangements

Abstract

Systems and methods for adapting a de-jitter buffer to conform to air link conditions. An air link characteristic may be detected before that characteristic begins to affect packet delivery, such as by slowing or speeding delivery delay at a subscriber station. A receiver-side de-jitter buffer, which adds delay to received packets, may adaptively adjust its size based upon the detected air link characteristic, such that the de-jitter buffer is appropriately sized for anticipated data packets before they are received at the subscriber station.

Claims

1. A method for adapting a de-jitter buffer for voice communications, the method comprising:

detecting a change in a characteristic of an air link, wherein the change in the characteristic of the air link is based on at least one of signal-to-interference-and-noise ratio (SINR) and sector signal quality;

predicting a future packet delay based on the change in the characteristic, wherein the predicted future packet delay is inversely proportional to the change in the characteristic of the air link; and

adapting the de-jitter buffer based on the predicted future packet delay before the change in the characteristic of the air link affects packet arrival times, wherein the adapting comprises increasing or decreasing the de-jitter buffer size by an amount based on the predicted future packet delay.

2. The method of claim 1, wherein the change in the characteristic of the air link is based on the SINR.

3. The method of claim 1, wherein the change in the characteristic is based on the sector signal quality.

4. The method of claim 3, wherein the change in the characteristic is based on variance in the sector signal quality.

5. The method of claim 1, wherein the predicted future packet delay is an increase in packet delay, and wherein the de jitter buffer is adapted by increasing its size.

6. The method of claim 1, wherein the predicted future packet delay comprises a decrease in packet delay, and wherein the de-jitter buffer is adapted by decreasing its size.

7. A method as in claim 1, wherein adapting the de-jitter buffer further comprises:

initializing the de-jitter buffer based on the predicted future packet delay.

8. The method of claim 7, wherein the de-jitter buffer is initialized to a size calculated as a function of the predicted future packet delay.

9. A non-transitory computer readable media embodying a program of instructions executable by a computer to perform a method of adapting a de-jitter buffer, the method comprising:

detecting a change in a characteristic of an air link, wherein the change in the characteristic of the air link is based on at least one of signal-to-interference-and-noise ratio (SINR) and sector signal quality;

predicting a future packet delay based on the change in the characteristic of the air link, wherein the predicted future packet delay is inversely proportional to the change in the characteristic of the air link; and

adapting the de jitter buffer based on the predicted future packet delay before the change in the characteristic of the air link affects packet arrival times, wherein the adapting comprises increasing or decreasing the de-jitter buffer size by an amount based on the predicted future packet delay.

10. A method for adapting a de-jitter buffer for voice communications, the method comprising:

detecting a change in a characteristic of an air link, wherein the change in the characteristic is based on at least one of packet error rate and sector loading;

predicting a future packet delay based on the change in the characteristic, wherein the predicted future packet delay is proportional to the change in characteristic; and

adapting the de-jitter buffer based on the predicted packet delay before the change in the characteristic affects packet arrival times, wherein the adapting comprises increasing or decreasing the de-jitter buffer size by an amount based on the predicted packet delay.

11. A subscriber station, comprising:

a receiver configured to receive communications signals over a wireless air link;

a processor configured to receive measurements of an air link characteristic, predict a future packet delay based on a change in the air link characteristic, and calculate and adapt a de-jitter buffer size based on the predicted future packet delay before the change in the air link characteristic affects packet arrival times, wherein the predicted future packet delay is inversely proportional to the change in the air link characteristic, wherein the adapting comprises increasing or decreasing the de-jitter buffer size by an amount based on the predicted future packet delay, and wherein the change in the air link characteristic is based on at least one of signal-to-interference-and-noise ratio (SINR) and sector signal quality; and

a de-jitter buffer configured to have an adaptable size capable of conforming to the calculated de-jitter buffer size.

12. The subscriber station of claim 11, wherein the change in the air link characteristic is based on the SINR.

13. The subscriber station of claim 11, wherein the change in the air link characteristic is based on the sector signal quality.

14. The subscriber station of claim 13, wherein the change in the air link characteristic is based on variance in the sector signal quality.

15. A jitter compensation apparatus, comprising:

means for detecting a change in a characteristic of an air link, wherein the change in the characteristic of the air link is based on at least one of signal-to-interference-and-noise ratio (SINR) and sector signal quality;

means for predicting a future packet delay based on the change in the characteristic, wherein the predicted future packet delay is inversely proportional to the change in the characteristic of the air link;

means for storing data packets;

means for storing the predicted future packet delay corresponding to each data packet; and

means for adjusting a size of the de-jitter buffer based on the predicted future packet delay before the change in the characteristic of the air link affects packet arrival times, wherein the adjusting comprises increasing or decreasing the de-jitter buffer size by an amount based on the predicted future packet delay.

16. The apparatus as in claim 15, wherein the apparatus is adapted to process Voice over Internet Protocol (VoIP) data.

17. The apparatus as in claim 15, wherein the sector signal quality is a function of sector loading in a wireless communication system.

18. The apparatus as in claim 17, wherein the sector signal quality is a function of a reverse activity bit.

19. The apparatus as in claim 17, wherein the sector signal quality is a function of a traffic channel valid bit.

20. The apparatus as in claim 15, wherein the apparatus is adapted to adjust the size of the de-jitter buffer to anticipate a handoff.

21. The apparatus as in claim 15, wherein the means for adjusting incorporates time-warping.

22. The apparatus as in claim 21, wherein time-warping is a function of a rate of data received.