Adjusting a jitter buffer based on inter arrival jitter

• US 9,882,818 B2
• Filed: 09/29/2014
• Issued: 01/30/2018
• Est. Priority Date: 09/30/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Shao, Tiange, Tackin, Onur E., Elrad, Oren M.
• Primary Examiner(s): Mesfin, Yemane
• Assistant Examiner(s): Elmejjarmi, Abdelillah
• Application Number:
  US14/500,059
• Publication Number:
  US 20150092585A1
• Time in Patent Office: 1,219 Days
• CPC Class Codes: H04L 43/0835 One way packet loss
• CPC Class Codes: H04L 43/087 Jitter
• CPC Class Codes: H04L 47/2416 Real-time traffic
• 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 47/564 Attaching a deadline to packets, e.g. earliest due date first
• CPC Class Codes: H04L 65/65 Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP]
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04W 28/0236 radio quality, e.g. interference, losses or delay
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication

Abstract

This disclosure relates to adjusting a jitter buffer at a wireless device based on inter-arrival-jitter (IAJ). In one embodiment, an IAJ value may be calculated for each of multiple received packets. An IAJ distribution may be generated for the received packets. A target packet loss rate may be determined. A quality of service value for IAJ distributions corresponding to the target packet loss rate may be determined. A de-jitter delay value may be calculated based on the IAJ distribution and the quality of service value for IAJ distributions. The de-jitter delay value may be used to adjust the jitter buffer at the wireless device.

Claims

1. A wireless user equipment (UE) device, comprising:

a radio; and

a processing element;

wherein the radio and the processing element are configured to;

wirelessly receive a plurality of audio data packets via the radio, wherein the plurality of audio data packets correspond to a first application of a first application type;

calculate an inter-arrival-jitter (IAJ) value for each of the plurality of received audio data packets;

generate an IAJ distribution for the plurality of received audio data packets;

determine a target packet loss rate for the audio data packets based on the first application type;

determine a quality of service (QoS) value for use in determining a de-jitter delay value, wherein the QoS value is mapped from the target packet loss rate based on a first probability distribution;

calculate the de-jitter delay value based on the IAJ distribution generated for the plurality of received audio packets and the QoS value, wherein the de-jitter delay value corresponds to the target packet loss rate, and wherein said calculating the de jitter delay value comprises applying the QoS value to the IAJ distribution to determine the de-jitter delay value;

perform playback of the received audio data packets, wherein the performing is based at least in part on the de-jitter delay value; and

performing;

receiving additional audio data packets of the first application,

updating the IAJ distribution based on the additional audio data packets,

recalculating the de-litter delay value by applying the QoS value to the updated IAJ distribution, and

performing playback using the recalculated de-jitter delay value repeatedly throughout execution of the first application.

2. The UE of claim 1,

wherein the audio data packets are received as part of a voice call,

wherein the de-jitter delay value is calculated for each talkspurt of the voice call.

3. The UE of claim 1,

wherein the IAJ for each respective received audio data packet is calculated based on realtime transport protocol (RTP) timestamps and arrival times at the UE of the respective received audio packet and an audio packet received immediately preceding the respective received audio packet.

4. The UE of claim 1,

wherein updating the IAJ distribution further comprises removing IAJ values of one or more earlier received audio data packets from the IAJ distribution.

5. The UE of claim 1,

wherein the audio data packets are received as part of a Voice over LTE (VoLTE) call.

6. A method for a wireless user equipment (UE) device to select a de-jitter delay based on inter-arrival-jitter (IAJ), the method comprising:

by the UE;

wirelessly receiving a plurality of packets corresponding to a first application of a first application type;

calculating an IAJ value for each respective packet of the plurality of received packets;

generating an IAJ distribution for the plurality of received packets using the IAJ values of the plurality of received packets;

determining a target packet loss rate for received packets based on the first application type;

determining a quality of service (QoS) value for use in determining a de-jitter delay value, wherein the QoS value is mapped from the target packet loss rate based on a first probability distribution;

calculating the de-jitter delay value based on the IAJ distribution generated for the plurality of received audio packets and the QoS, value, wherein the de-jitter delay value corresponds to the target packet loss rate, and wherein said calculating the de jitter delay value comprises applying the QoS value to the IAJ distribution to determine the de-jitter delay value;

performing playback of the plurality of packets, wherein the performing is based at least in part on the de-jitter delay value; and

performing;

receiving additional packets of the first application,

updating the IAJ distribution based on the additional packets,

recalculating the de jitter delay value by applying the QoS value to the updated IAJ distribution, and

performing playback using the recalculated de-jitter delay value repeatedly throughout execution of the first application.

7. The method of claim 6, wherein calculating an IAJ value for a respective received packet comprises:

subtracting a real-time transport protocol (RTP) timestamp of a previously received packet from a RTP timestamp of the respective received packet, resulting in a RTP timestamp difference;

subtracting a packet arrival timestamp of the previously received packet from a packet arrival timestamp of the respective received packet, resulting in a packet arrival timestamp difference;

subtracting the RTP timestamp difference from the packet arrival timestamp difference, resulting in an IAJ value for the respective received packet.

8. The method of claim 6,

wherein updating the IAJ distribution further comprises removing one or more oldest IAJ values from the IAJ distribution to maintain a predetermined maximum number of data points.

9. The method of claim 6,

wherein updating the IAJ distribution further comprises removing one or more IAJ values that are older than a time threshold from the IAJ distribution.

10. The method of claim 6, wherein said re-calculating the de-jitter delay value using the updated IAJ distribution is based on one or more predefined trigger conditions.

11. The method of claim 10,

wherein the plurality of received packets are audio data packets for a voice call,

wherein the one or more predefined trigger conditions comprise a talkspurt of the voice call ending.

12. The method of claim 6,

wherein the plurality of received packets are audio data packets for a voice call,

wherein the target packet loss rate is a maximum acceptable packet loss rate for the voice call.

13. A non-transitory computer-readable memory medium that stores instructions that, when executed at a wireless device, cause the wireless device to:

determine a target packet loss rate for data packets corresponding to a first application based at least in part on a first application type of the first application;

wirelessly receive a plurality of data packets corresponding to the first application type;

calculate an inter-arrival-jitter (IAJ) value for each of the plurality of received data packets;

generate an IAJ distribution for the plurality of received data packets based on the calculated IAJ values;

determine a quality of service (QoS) value for use in determining a de-jitter delay value, wherein the first value is mapped from the target packet loss rate for data packets corresponding to the first application type based on a first probability distribution;

calculate the de-jitter delay value which meets the target packet loss rate for data packets corresponding to the first application type based on the IAJ distribution generated for the plurality of received audio packets and the QoS value, wherein said calculating the de jitter delay value comprises applying the QoS value to the IAJ distribution to determine the de-jitter delay value;

perform presentation of the plurality of data packets using the de-jitter delay value; and

perform;

wirelessly receiving additional data packets of the first application,

updating the IAJ distribution based on the additional data packets,

recalculating the de-jitter delay value by applying the QoS value to the updated IAJ distribution, and

performing presentation using the recalculated de-jitter delay value repeatedly throughout execution of the first application.

14. The non-transitory computer-readable memory medium of claim 13, wherein the QoS value for use in determining a de-jitter delay value is calculated using the following equation:

P_QoS=0.5+0.5erf(√

{square root over (2)}erf⁻

(2PLR−

1))

wherein P_QoS represents a QoS value for use in determining the de-jitter delay value, wherein PLR represents a packet loss rate corresponding to that P_QoS based on the first probability distribution.

15. The non-transitory computer-readable memory medium of claim 13, wherein updating the IAJ distribution comprises:

removing IAJ values of data packets which have aged out of an IAJ distribution calculation window.

16. The non-transitory computer-readable memory medium of claim 13,

wherein the application type is a real-time audio, video, or audiovisual application.

17. The non-transitory computer-readable memory medium of claim 16,

wherein the IAJ value for each received data packet is calculated based on real-time transport protocol timestamps and local arrival timestamps for the received data packet and a sequentially preceding data packet.