System for real time communication buffer management

• US 6,434,606 B1
• Filed: 05/28/1999
• Issued: 08/13/2002
• Est. Priority Date: 10/01/1997
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Borella, Michael S., Sidhu, Ikhlaq S., Schuster, Guido M., Mahler, Jerry J., Kostas, Thomas J.
• Primary Examiner(s): Coulter, Kenneth R.
• Application Number:
  US09/322,561
• Time in Patent Office: 1,173 Days
• Field of Search: 709/231, 709/214, 711/148
• US Class Current: 709/214
• 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: H04J 3/0638 Clock or time synchronisation among nodes; Internode synchronisation synchronization for ring networks H04L12/422; data switching networks with synchronous transmission H04L12/43
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/5616 Terminal equipment, e.g. codecs, synch.
• CPC Class Codes: H04L 2012/5647 Cell loss
• CPC Class Codes: H04L 2012/5649 Cell delay or jitter
• CPC Class Codes: H04L 2012/5671 Support of voice
• CPC Class Codes: H04L 2012/5674 Synchronisation, timing recovery or alignment
• CPC Class Codes: H04L 2012/5681 Buffer or queue management
• CPC Class Codes: H04L 2012/6429 Terminal adapters
• CPC Class Codes: H04L 2012/6472 Internet
• CPC Class Codes: H04L 2012/6475 N-ISDN, Public Switched Telephone Network [PSTN]
• CPC Class Codes: H04L 2012/6481 Speech, voice
• CPC Class Codes: H04L 2012/6483 Video, e.g. MPEG
• CPC Class Codes: H04L 2012/6489 Buffer Management, Threshold setting, Scheduling, Shaping
• CPC Class Codes: H04L 49/206 Real Time traffic
• CPC Class Codes: H04L 49/253 using establishment or release of connections between ports
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports
• CPC Class Codes: H04L 49/557 Error correction, e.g. fault recovery or fault tolerance
• CPC Class Codes: H04L 65/1101 : Session protocols
• CPC Class Codes: H04L 65/752 : adapting media to network capabilities
• CPC Class Codes: H04L 65/764 : at the destination reformatting of additional data in video clients H04N21/4355
• CPC Class Codes: H04L 65/80 : Responding to QoS
• CPC Class Codes: H04Q 11/0478 : Provisions for broadband connections

Abstract

A system and method for receiving a transported stream of data packets includes a buffer management device for receiving the data packets, unpacking the data packets, and forwarding a stream of data frames. The system and method further includes a first jitter buffer for receiving the data frames from the buffer management device and buffering the data frames, and a second jitter buffer for receiving the data frames from the buffer management device and buffering the data frames. In addition, the system and method includes a computationally-desirable jitter buffer selected from the first jitter buffer or the second jitter buffer by comparing a first jitter buffer quality and a second jitter buffer quality. The system and method also includes a decoder for receiving buffered data frames from the computationally-desirable jitter buffer.

Claims

1. A gateway for receiving a transported stream of data packets comprising:

a buffer management device receiving the data packets, unpacking the data packets and forwarding a stream of data frames;

a first jitter buffer receiving the data frames from the buffer management device and buffering the data frames;

a second jitter buffer receiving the data frames from the buffer management device and buffering the data frames;

a computationally-desirable jitter buffer selected from the first jitter buffer or the second jitter buffer, the computationally-desirable jitter buffer selected by comparing a first jitter buffer quality and a second jitter buffer quality; and

a decoder receiving buffered data frames from the computationally-desirable jitter buffer.

2. The invention of claim 1 wherein the buffer management device uses one of redundancy and forward error correction coding to recover lost data packets.

3. The invention of claim 1 wherein the jitter buffer quality comprises at least one jitter buffer value and at least one receiver sensitivity setting.

4. The invention of claim 3 wherein the jitter buffer value is selected from a group including mean buffer depth, mean loss rate, and bandwidth.

5. The invention of claim 3 wherein the receiver sensitivity setting is selected from the group including packet delay, packet loss, and bandwidth.

6. The invention of claim 1 wherein the decoder plays out the data frames received from the computationally-desirable jitter buffer.

7. The invention of claim 1 wherein the jitter buffer quality is user definable.

8. The invention of claim 1 wherein the computationally-desirable jitter buffer is periodically selected.

9. The invention of claim 3 wherein the sensitivity setting is user definable.

10. The invention of claim 1 wherein the jitter buffer quality is used for evaluating a dynamic characteristic of a transporting medium that transports the data packets from an encoding device to the gateway.

11. The invention of claim 1 wherein the jitter buffer quality is computed using an exponentially weighted moving average.

12. The invention of claim 11 wherein the exponentially weighted moving average is computed over a plurality of time periods.

13. The invention of claim 1 wherein the jitter buffer quality is computed using a second-order statistical analysis.

14. The invention of claim 13 wherein the second-order statistical analysis is a Poisson process.

15. A method for receiving a transported stream of data packets comprising the steps of:

receiving the data packets at a management module;

unpacking the data packets at the management module;

forwarding a first stream of data frames to a first jitter buffer;

forwarding a second stream of data frames to a second jitter buffer;

buffering the data frames at the first jitter buffer and the second jitter buffer;

computing a first jitter buffer quality for the first jitter buffer and a second jitter buffer quality for the second jitter buffer;

selecting either the first or the second jitter buffer as a computationally-desirable jitter buffer based on the first and second jitter buffer qualities; and

forwarding the buffered data frames from the computationally-desirable buffer to a decoder.

16. The invention of claim 15 wherein the jitter buffer quality comprises at least one jitter buffer value and at least one receiver sensitivity setting.

17. The invention of claim 16 wherein the jitter buffer value is selected from a group including mean buffer depth, mean loss rate, and bandwidth.

18. The invention of claim 16 wherein the receiver sensitivity setting is selected from a group including packet delay, packet loss, and bandwidth.

19. The invention of claim 15 further comprising the step of playing out the data frames received from the computationally-desirable jitter buffer.

20. The invention of claim 15 wherein the jitter buffer quality is user definable.

21. The invention of claim 15 further comprising the step of periodically selecting the computationally-desirable jitter buffer.

22. The invention of claim 16 wherein the sensitivity setting is user definable.

23. The invention of claim 15 further comprising the step of evaluating dynamic characteristics of a network that transports the data packets from an encoding device to the gateway.

24. The invention of claim 15 further comprising the step of computing the jitter buffer quality as an exponentially weighted moving average.

25. The invention of claim 24 further comprising the step of computing the exponentially weighted moving average over a plurality of time periods.

26. The invention of claim 15 wherein the jitter buffer quality is computed using a second-order statistical analysis.

27. The invention of claim 15 further comprising the step of simulating the arrival of further redundancy frames for each jitter buffer with a redundancy value greater than a redundancy value of the data packets.

28. The invention of claim 15 further comprising the step of simulating the arrival of forward error correction frames for each jitter buffer with an forward error correction scheme.

29. The invention of claim 15 further comprising the step of forwarding a silence frame from the computationally-desirable buffer to the decoder when there is no buffered data frame present in the computationally-desirable buffer.

30. The invention of claim 15 further comprising the steps of recovering missing data frames and inserting the missing data frames into at least one of the jitter buffers.

31. The invention of claim 26 wherein the second-order statistical analysis is a Poisson process.