VOIP transmitter and receiver devices and methods therefor

• US 20040001477A1
• Filed: 06/26/2002
• Published: 01/01/2004
• Est. Priority Date: 06/26/2002
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Kyperountas, Spyros, DʼAmico, Thomas Victor, Gorday, Paul Edward
• Granted Patent: US 6,999,447 B2
• Time in Patent Office: Days
• US Class Current: 370/352
• 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 47/2416 Real-time traffic
• CPC Class Codes: H04L 47/26 using explicit feedback to the source, e.g. choke packets
• CPC Class Codes: H04L 47/28 in relation to timing considerations
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 47/38 by adapting coding or compression rate
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/0231 based on communication conditions dynamic wireless traffic scheduling definition based on channel quality criteria H04W72/54
• CPC Class Codes: H04W 28/0278 using buffer status reports dynamic wireless traffic scheduling definition H04W72/12
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

A Voice Over Internet Protocol (VOIP) receiver (630), operating in conjunction with a transmitter (606) receives a sequence of voice packets representing a speech utterance transmitted over a VOIP wireless interface (112). A receive packet buffer (120) buffers the received sequence of voice packets after receipt and before playback of reconstructed speech. A processor (650), operating under program control, determines a transmission buffer (108) delay of a first packet in the sequence of packets representing the speech utterance. The control processor (650) further sets a prescribed amount of delay in the receive packet buffer (120) based upon the transmission buffer (108) delay so that the transmission buffer delay+receive buffer delay=a predetermined total delay. The status of the receiver buffer (120) is monitored and tracked by or fed back to the transmitter side to minimize receive buffer (120) under-runs by use of CDMA soft capacity (200), link dependent prioritization (300), real-time packet prioritization (400) and/or variation of vocoder (624) rates (500).

Claims

1. A Voice Over Internet Protocol (VOIP) transmitter device, comprising:

a transmission buffer that buffers a plurality of packets, the transmission buffer having a transmission buffer delay;

means for receiving a sequence of packets that encode a speech utterance using VOIP; and

means for transmitting an initial buffer delay value along with a first packet in the sequence of packets that encode the speech utterance over a wireless network.

2. The apparatus according to claim 1, further comprising:

a vocoder that digitally encodes speech signals at a specified vocoder rate; and

means for adjusting the vocoder rate based upon a measure of traffic loading of the wireless network.

3. The apparatus according to claim 2, wherein the vocoder rate is increased if traffic loading does not exceed a short-term target capacity and the vocoder rate is decreased if traffic loading exceeds said short-term target capacity.

4. The apparatus according to claim 1, further comprising:

means for determining real-time and non-real-time traffic loading on the wireless network;

means for prioritizing real-time traffic higher than non-real-time traffic if a measure of traffic loading exceeds a short term traffic loading capacity target.

5. The apparatus according to claim 1, wherein the wireless network comprises a Code Division Multiple Access (CDMA) wireless network.

6. The apparatus according to claim 5, further comprising:

means for monitoring values of receive buffer delays for receivers operating on the wireless CDMA network;

means for determining a congestion level of the wireless CDMA network;

means for determining if a short term degradation of the wireless CDMA network'"'"'s overall performance as measured by carrier/(noise+interference) is acceptable; and

if the receive buffer delays are smaller than a predetermined threshold, and if the congestion level is greater than a predetermined threshold and if a degradation of the wireless CDMA network'"'"'s overall performance is acceptable, then increasing the wireless CDMA network'"'"'s soft capacity to increase throughput of transmitted packets.

7. The apparatus according to claim 5, further comprising:

means for monitoring values of receive buffer delays for receivers operating on the wireless CDMA network;

means for determining a congestion level of the wireless CDMA network;

means for identifying bit rates of links on the wireless CDMA network; and

means for prioritizing communications with links based upon the bit rates of the links such that the lower the low bit rate, the higher the priority.

8. The apparatus according to claim 1, further comprising a vocoder that encodes speech utterances into said sequence of packets.

9. The apparatus according to claim 1, wherein the initial buffer delay value comprises the initial transmission buffer delay value.

10. The apparatus according to claim 1, wherein the initial buffer delay value comprises the initial receive buffer delay value.

11. The apparatus according to claim 1, wherein the initial receive buffer delay value=a predetermined delay value−

the initial transmission buffer delay value.

12. The apparatus according to claim 1, wherein the initial buffer delay value comprises an absolute time stamp that enables derivation of the initial receive buffer delay value.

13. A Voice Over Internet Protocol (VOIP) transmitter device, comprising:

a transmission buffer that buffers a plurality of packets, the transmission buffer having a transmission buffer delay;

means for receiving a sequence of packets that encode a speech utterance using VOIP; and

a transmitter that transmits an initial buffer delay value along with a first packet in the sequence of packets that encode the speech utterance over a wireless CDMA network.

14. The apparatus according to claim 13, further comprising:

a vocoder that digitally encodes speech signals at a specified vocoder rate; and

a programmed control processor operating under program control to adjust the vocoder rate based upon a measure of traffic loading of the CDMA wireless network.

15. The apparatus according to claim 14, wherein the vocoder rate is increased if traffic loading does not exceed a short-term target capacity and the vocoder rate is decreased if traffic loading exceeds said short-term target capacity.

16. The apparatus according to claim 13, further comprising:

means for determining real-time and non-real-time traffic loading on the wireless network;

a control processor operating under program control to prioritize real-time traffic higher than non-real-time traffic if a measure of traffic loading exceeds a short term traffic loading capacity target.

17. The apparatus according to claim 13, further comprising:

means for monitoring values of receive buffer delays for receivers operating on the wireless CDMA network;

a programmed processor carrying out programmed instructions to;

determine a congestion level of the wireless CDMA network;

determine if a short term degradation of the wireless CDMA network'"'"'s overall performance as measured by carrier/(noise+interference) is acceptable; and

if the receive buffer delays are smaller than a predetermined threshold, and if the congestion level is greater than a predetermined threshold and if a degradation of the wireless CDMA network'"'"'s overall performance is acceptable, then increase the wireless CDMA network'"'"'s soft capacity to increase throughput of transmitted packets.

18. The apparatus according to claim 13, further comprising:

means for monitoring values of receive buffer delays for receivers operating on the wireless CDMA network;

a programmed processor carrying out programmed instructions to;

determine a congestion level of the wireless CDMA network;

identify bit rates of links on the wireless CDMA network; and

prioritize communications with links based upon the bit rates of the links such that the lower the low bit rate, the higher the priority.

19. The apparatus according to claim 13, further comprising a vocoder that encodes speech utterances into said sequence of packets.

20. The apparatus according to claim 13, wherein the initial buffer delay value comprises the initial transmission buffer delay value.

21. The apparatus according to claim 13, wherein the initial buffer delay value comprises the initial receive buffer delay value.

22. The apparatus according to claim 13, wherein the initial receive buffer delay value=a predetermined delay value−

the initial transmission buffer delay value.

23. The apparatus according to claim 13, wherein the initial buffer delay value comprises an absolute time stamp that enables derivation of the initial receive buffer delay value.

24. A method of operating a Voice Over Internet Protocol (VOIP) transmitter device, comprising:

buffering a plurality of packets in a transmission buffer, the transmission buffer having a transmission buffer delay;

receiving a sequence of packets that encode a speech utterance using VOIP; and

transmitting an initial buffer delay value along with a first packet in the sequence of packets that encode the speech utterance over a wireless network.

25. The method according to claim 24, wherein the wireless network comprises a Code Division Multiple Access (CDMA) wireless network.

26. The method according to claim 24, wherein the initial buffer delay value comprises the initial transmission buffer delay value.

27. The method according to claim 24, wherein the initial buffer delay value comprises the initial receive buffer delay value.

28. The method according to claim 24, wherein the initial buffer delay value comprises an absolute time stamp that enables derivation of the initial receive buffer delay value.

29. A Voice Over Internet Protocol (VOIP) receiver device, comprising:

a receiver that receives a sequence of voice packets representing a speech utterance transmitted over a VOIP wireless interface;

a receive packet buffer that buffers the received sequence of voice packets after receipt and before playback of reconstructed speech;

means for reading an initial transmission buffer delay of a first packet in the sequence of packets representing the speech utterance; and

means for setting a prescribed amount of delay in said receive packet buffer based upon the initial transmission buffer delay so that the initial transmission buffer delay+initial receive buffer delay=a predetermined total delay.

30. The apparatus according to claim 29, further comprising a transmitter that transmits the value of the initial transmission buffer delay.

31. The apparatus according to claim 29, wherein the receiver comprises a CDMA wireless receiver.

32. A Voice Over Internet Protocol (VOIP) receiver device, comprising:

a receiver that receives a sequence of voice packets representing a speech utterance transmitted over a VOIP wireless interface;

a receive packet buffer that buffers the received sequence of voice packets after receipt and before playback of reconstructed speech;

means for reading an initial receive buffer delay of a first packet in the sequence of packets representing the speech utterance; and

means for setting a prescribed amount of delay in said receive packet buffer=the initial receive buffer delay.

33. The apparatus according to claim 32, further comprising a transmitter that transmits the value of the initial receive buffer delay.

34. The apparatus according to claim 32, wherein the receiver comprises a CDMA wireless receiver.

35. A Voice Over Internet Protocol (VOIP) receiver device, comprising:

a receiver that receives a sequence of voice packets representing a speech utterance transmitted over a VOIP wireless interface;

a receive packet buffer that buffers the received sequence of voice packets after receipt and before playback of reconstructed speech;

means for reading an absolute time stamp of a first packet in the sequence of packets representing the speech utterance; and

means for setting a prescribed amount of delay in said receive packet buffer derived from the absolute time stamp and a synchronized time reference

36. The apparatus according to claim 35, further comprising a transmitter that transmits the absolute time stamp.

37. The apparatus according to claim 35, wherein the receiver comprises a CDMA wireless receiver.

38. A method of operating a Voice Over Internet Protocol (VOIP) receiver device, comprising:

receiving a sequence of voice packets representing a speech utterance transmitted over a VOIP wireless interface;

buffering the received sequence of voice packets after receipt and before playback of reconstructed speech;

determining an initial receive buffer delay for the sequence of packets representing the speech utterance; and

setting the initial receive buffer delay.

39. The method according to claim 38, wherein the determining comprises receiving an initial receive buffer delay along with a first packet in said sequence of voice packets.

40. The method according to claim 38, wherein the determining comprises:

receiving an initial transmission buffer delay value; and

computing an initial receive buffer delay as a predetermined total delay−

the initial transmission buffer delay=initial receive buffer delay.

41. The method according to claim 40, wherein the initial transmission buffer delay is read from the first packet in the sequence of packets.

42. The method according to claim 38, further comprising transmitting the value of the initial receive buffer delay.

43. The method according to claim 38, wherein the determining comprises:

receiving an absolute time stamp; and

computing an initial receive buffer delay based on the absolute time stamp and a synchronized time reference.