PACKET PRIORITIZATION AND ASSOCIATED BANDWIDTH AND BUFFER MANAGEMENT TECHNIQUES FOR AUDIO OVER IP

• US 20080151921A1
• Filed: 02/07/2008
• Published: 06/26/2008
• Est. Priority Date: 09/30/2002
• Status: Active Grant

• Current Assignee: Arlington Technologies, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Avaya Incorporated
• Inventors: Gentle, Christopher R., Michaelis, Paul Roller
• Granted Patent: US 7,877,501 B2
• Time in Patent Office: Days
• US Class Current: 370/412
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/2408 for supporting different services, e.g. a differentiated services [DiffServ] type of service
• CPC Class Codes: H04L 47/2416 Real-time traffic
• CPC Class Codes: H04L 47/2433 Allocation of priorities to traffic types
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 47/31 by tagging of packets, e.g. using discard eligibility [DE] bits
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/70 Media network packetisation

Abstract

The present invention is directed to voice communication devices in which an audio stream is divided into a sequence of individual packets, each of which is routed via pathways that can vary depending on the availability of network resources. All embodiments of the invention rely on an acoustic prioritization agent that assigns a priority value to the packets. The priority value is based on factors such as whether the packet contains voice activity and the degree of acoustic similarity between this packet and adjacent packets in the sequence. A confidence level, associated with the priority value, may also be assigned. In one embodiment, network congestion is reduced by deliberately failing to transmit packets that are judged to be acoustically similar to adjacent packets; the expectation is that, under these circumstances, traditional packet loss concealment algorithms in the receiving device will construct an acceptably accurate replica of the missing packet. In another embodiment, the receiving device can reduce the number of packets stored in its jitter buffer, and therefore the latency of the speech signal, by selectively deleting one or more packets within sustained silences or non-varying speech events. In both embodiments, the ability of the system to drop appropriate packets may be enhanced by taking into account the confidence levels associated with the priority assessments.

Claims

1. A method for managing a receive buffer, comprising:

providing a receive buffer, the receive buffer containing a plurality of packets associated with voice communications; and

based on a level of importance associated with at least some of the plurality of packets, removing at least some of the packets from the receive buffer while leaving other packets in the receive buffer.

2. The method of claim 1, wherein the level of importance associated with each packet is indicated by a corresponding value marker.

3. The method of claim 1, further comprising:

determining when at least one of a delay associated with the receive buffer and a length of the receive buffer exceeds a predetermined level;

when the at least one of a delay and length exceeds the predetermined level, performing the removing step; and

when the at least one of a delay and length does not exceed the predetermined level, not performing the removing step.

4. The method of claim 1, further comprising:

for at least some packets remaining in the receive buffer, resetting a packet counter indicating an ordering of the packets.

5. The method of claim 1, further comprising:

assigning a packet counter of a removed packet to a packet remaining in the receive buffer.

6. The method of claim 1, further comprising:

performing time compression around at least one of the removed packets.

7. The method of claim 1 further comprising before the removing step:

receiving a voice stream from a user, the voice stream comprising a plurality of temporally distinct segments;

processing at least one selected first segment of the voice stream, wherein the processing step comprises at least one of the following substeps;

determining whether or not the contents of the selected first segment are the product of voice activity and, when the contents are determined to be a product of voice activity, a level of confidence that the voice activity determination is accurate;

determining a type of voice activity associated with the contents of the first segment; and

comparing the first segment with a second segment of the voice stream to determine a degree of acoustic similarity between the first and second segments, wherein the processing of the first segment is based on at least one of the level of confidence, the type of voice activity, and the degree of acoustic similarity.

8. The method of claim 7, further comprising:

based on the at least one of the level of confidence, the type of voice activity, and the degree of acoustic similarity, assigning an importance to the first segment.

9. The method of claim 8, wherein the importance is a value marker and further comprising:

incorporating the value marker into a first packet comprising the first segment.

10. The method of claim 8, wherein the importance is a service class assigned to a first packet comprising the first segment.

11. The method of claim 8, wherein the importance is a transmission priority assigned to a first packet comprising the first segment.

12. A computer readable medium to perform the steps of claim 1.

13. A logic circuit configured to perform the steps of claim 1.

14. A system for managing a receive buffer, comprising:

a receive buffer containing a plurality of packets associated with voice communications; and

a buffer manager operable to remove at least some of the packets from the receive buffer while leaving other packets in the receive buffer based on a level of importance associated with at least some of the plurality of packets.

15. The system of claim 14, wherein the level of importance of the at least some packets is indicated by a corresponding value marker.

16. The system of claim 14, wherein the buffer manager is further operable to:

determine if at least one of a delay associated with the receive buffer and a number of packets enqueued in the receive buffer exceeds a predetermined level;

when the at least one of a delay and number of packets exceeds the predetermined level, performing the removing step; and

when the at least one of a delay and number of packets does not exceed the predetermined level, not performing the removing step.

17. The system of claim 14, wherein the buffer manager is operable, for at least some packets remaining in the receive buffer, to reset a packet counter indicating an ordering of the packets.

18. The system of claim 14, wherein the buffer manager is operable to assign a packet counter of a removed packet to a packet remaining in the receive buffer.

19. The system of claim 14, wherein the buffer manager is operable to perform time compression around at least one of the removed packets.