METHOD OF SCHEDULING TRANSMISSION IN A COMMUNICATION NETWORK, CORRESPONDING COMMUNICATION NODE AND COMPUTER PROGRAM PRODUCT

• US 20120250678A1
• Filed: 12/24/2009
• Published: 10/04/2012
• Est. Priority Date: 12/24/2009
• Status: Active Grant

• Current Assignee: Telecom Italia S.p.A.
• Original Assignee: Telecom Italia S.p.A.
• Inventors: Sabella, Dario, Caretti, Marco, Andreozzi, Matteo Maria, Stea, Giovanni
• Granted Patent: US 9,036,624 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 47/127 by using congestion prediction
• 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 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 47/564 Attaching a deadline to packets, e.g. earliest due date first

Abstract

Data streams are transmitted from a node towards a receiver in a communication network in the form of data packets for playout via a reproduction buffer at the receiver. The data packets are arranged in a scheduling queue and dropped from the scheduling queue if their sojourn time in the queue exceeds a given drop deadline. The reproduction buffer is emulated at the node in order to determine respective playout values for the data packets which are indicative of expected playout instants for the data packets by the reproduction buffer at the receiver. The drop deadlines are assigned to the data packets as a function of the respective playout values determined via the reproduction buffer as emulated at the node.

Claims

1. A method of scheduling transmission of data streams from a node towards a receiver in a communication network, wherein said data streams include data packets for playout via a reproduction buffer at the receiver, the method including:

arranging said data packets in at least one scheduling queue at said node;

dropping data packets from said scheduling queue if their sojourn time in said scheduling queue exceeds a given drop deadline;

emulating at said node said reproduction buffer to determine respective playout values for said data packets indicative of expected playout instants for said data packets by said reproduction buffer, and

assigning said drop deadlines to said data packets as a function of said respective playout values.

2. The method of claim 1, wherein said data packets include timestamps indicative of the generation time of said data packets.

3. The method of claim 1, including determining said respective playout values as a function of an estimated transmission delay between the generation time of said packets at a sender in said communication network and the arrival time of said packets at the receiver.

4. The method of claim 3, wherein said estimated transmission delay is determined as a function of:

a first value indicative of the time said data packets are generated at said sender,

a second value indicative of the time said data packets are received at said node,

a third value indicative of the expected time said data packets are transmitted from said node to said receiver, and

a fourth value indicative of the estimated delay for transmitting said data packets from said communication node to said receiver.

5. The method of claim 3, including emulating said reproduction buffer at said node as an adaptive playout buffer.

6. The method of claim 5, wherein said respective playout values are determined as a function of a Quality of Service and/or Quality of Experience function.

7. The method of claim 6, wherein said respective playout values are determined as a function of a Mean Opinion Score or MOS.

8. The method of claim 7, wherein said data stream is a Voice over IP data stream, and wherein said Mean Opinion Score is calculated by the E-Model.

9. The method of claim 6, wherein said respective playout values are determined a posteriori, by determining an optimal playout delay as a function of previous transmission delays.

10. The method of claim 9, wherein said data stream is a Voice over IP data stream, and wherein said respective playout values are determined as indicative for the expected playout instant of all data packets of a given talkspurt by determining the optimal playout delay of the previous talkspurt.

11. The method of claim 9, wherein said respective playout values are determined by an exponential average taking into account previous values for said respective playout values.

12. The method of claim 1, wherein said assigning said drop deadlines to said data packets as a function of said respective playout values includes assigning to each data packet of said data stream a deadline, such that data packets are dropped if their expected transmission times exceed their expected playout instants.

13. A communication node for the scheduled transmission of data streams towards a receiver in a communication network, wherein said data streams include data packets for playout via a reproduction buffer at the receiver, the communication node comprising:

a control unit configured to;

arrange said data packets in at least one scheduling queue;

drop said data packets from said scheduling queue if their sojourn time in said scheduling queue exceeds a given drop deadline; and

emulate said reproduction buffer to determine respective playout values for said data packets indicative of expected playout instants for said data packets by said reproduction buffer.

14. The communication node of claim 13, wherein said communication node is a Universal Mobile Telecommunications System Long Term Evolution and/or High-Speed Downlink Packet Access communication node.

18. The communication node of claim 13, wherein the control unit is further configured to assign said drop deadlines to said data packets as a function of said respective playout values.

19. The communication node of claim 18, wherein the control unit is further configured to assign to each data packet of said data stream a deadline, such that data packets are dropped if their expected transmission times exceed their expected playout instants.

20. The communication node of claim 13, wherein the control unit is further configured to determine said respective playout values as a function of an estimated transmission delay between the generation time of said packets at a sender in said communication network and the arrival time of said packets at the receiver.

15. A computer readable storage medium having software code portions stored thereon that, when executed by at least one computer, perform the steps of:

arranging said data packets in at least one scheduling queue at said node;

dropping data packets from said scheduling queue if their sojourn time in said scheduling queue exceeds a given drop deadline;

emulating at said node said reproduction buffer to determine respective playout values for said data packets indicative of expected playout instants for said data packets by said reproduction buffer, and

assigning said drop deadlines to said data packets as a function of said respective playout values.

16. The computer readable storage medium according to claim 15, wherein the software code portions, when executed, further perform the step of:

determining said respective playout values as a function of an estimated transmission delay between the generation time of said packets at a sender in said communication network and the arrival time of said packets at the receiver.

17. The computer readable storage medium according to claim 15, wherein the software code portions, when executed, further perform the step of:

wherein said assigning said drop deadlines to said data packets as a function of said respective playout values includes assigning to each data packet of said data stream a deadline, such that data packets are dropped if their expected transmission times exceed their expected playout instants.