SYSTEM AND METHOD FOR ERROR-CONTROL FOR MULTICAST VIDEO DISTRIBUTION

• US 20020114283A1
• Filed: 08/30/2001
• Published: 08/22/2002
• Est. Priority Date: 08/30/2000
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Chinese University of Hong Kong
• Inventors: Lee, Jack Yiu-Bun
• Granted Patent: US 7,224,702 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 1/1819 with retransmission of additional or different redundancy
• CPC Class Codes: H04L 12/1863 comprising mechanisms for improved reliability, e.g. status reports arrangements for detecting or preventing errors by carrying supervisory signal the return channel H04L1/16

Abstract

Abstract of Disclosure

An embodiment of the invention includes an efficient error-control system and method for recovering packet losses, especially losses in distributing multicast video over broadband residential networks. Preferably, unlike most existing error-control algorithms designed for Internet multicast, the system and method does not employ substantial feedback suppression. Preferably, the system and method does not employ substantial multicasted retransmission. Preferably, the system and method does not employ substantial parity retransmission. Preferably, the system and method does not employ substantial local loss recovery. The system and method integrates two existing classes of error-control algorithms: Automatic Repeat Request (ARQ) and Forward Error Correction (FEC), to reduce traffic overhead and achieve scalability.

Claims

2. A method for handling communication errors in a communication system, the method comprising:

initiating transmission of an intended group of packets, the intended group of packets including a set of data and error-correcting information for the set of data;

receiving an indication of at least some data, of the set of data, that failed to be correctly received at a receiver;

in response to the indication, retransmitting a second group of packets, the second group of packets comprising less than all data, of the set of data, that failed to be correctly received at the receiver;

wherein less than all data that failed to be correctly received at the receiver is retransmitted in the retransmitting step, and the receiver will be able to obtain the all data, of the set of data, that failed to be correctly received at the receiver by performing error correction with the retransmitted second group of packets, once received, and correctly received portions of the intended group of packets, as received from the transmission that was initiated in the initiating step.

3. The method according to claim 2, wherein the communication system comprises a residential broadband network.

4. The method according to claim 2, wherein the set of data is a portion of a video, and the transmission is a portion of a multicast of the video.

5. The method according to claim 2, wherein the transmission of the intended group of packets to the receiver is not over the Internet.

6. The method according to claim 2, wherein the retransmitting is a unicasting.

7. The method according to claim 2, wherein the indication is received, in the receiving step, via a unicast from the receiver.

8. The method according to claim 2, further comprising, at the receiver:

sending the indication, wherein the indication indicates less than all data, of the set of data, that failed to be correctly received at the receiver, wherein the retransmitting step includes retransmitting all data indicated in the indication.

9. The method according to claim 8, wherein the sending step is initiated without waiting for all packets of the intended group of packets to either arrive at the receiver or be determined as being lost to the receiver.

10. The method according to claim 9, wherein the retransmitting step is initiated before every packet of the intended group of packets has either arrived at the receiver or been lost to the receiver.

11. The method according to claim 2, wherein:

some packets of the intended group of packets were not correctly received at the receiver; and

the method further comprises identifying a minimally-sized set of packets, of the some packets that were not correctly received at the receiver, that would enable recovery at the receiver of all data, of the set of data, not correctly received at the receiver.

12. The method according to claim 11, wherein:

the intended group of packets includes D intended data packets and R intended redundancy packets and no other data packets or redundancy packets;

M packets of the intended group of packets were not correctly received at the receiver, wherein M is greater than R; and

the step of identifying a minimally-sized set of packets comprises identifying a set of M minus R packets, of the M packets that were not correctly received at the receiver.

13. The method according to claim 12, further comprising, at the receiver:

initiating sending at least a portion of the indication if at least R plus one packets of the intended group of packets were not correctly received at the receiver, even before every packet of the intended group of packets has either arrived at the receiver or been determined as being lost to the receiver.

14. The method according to claim 2, further comprising, at the receiver:

receiving the retransmitted second group of packets; and

performing erasure correction on the second group of packets and the correctly received portions of the intended group of packets whose transmission was initiated in the initiating step to thereby obtain the all data, of the set of data, that failed to be correctly received at the receiver.

15. A method for receiving video content at a receiver, the method comprising:

receiving packets from a multicasted group of packets, wherein the multicasted group of packets include data and error-correction information for the data;

if packets received without error in the receiving step include less than all the data, whereby some of the data has been lost, hereinafter referred to as lost data, then;

16. The method according to claim 15, wherein the message identifies and requests retransmission of less than all lost data packets of the multicasted group of packets;

and wherein the retransmission includes retransmission of the less than all lost data packets of the multicasted group of packets.

17. The method according to claim 16, wherein the sending step includes sending at least a portion of the message, even before every packet of the multicasted group of packets has either arrived at the receiver or been determined as lost to the receiver.

18. A system for providing content, the system comprising:

a server that multicasts video data to a plurality of receivers in groups of packets, wherein the server is coupled to a broadband communication network, and wherein an intended group of packets includes a set of data and error-correcting information for the set of data, and wherein the server is configured;

19. The system according to claim 18, wherein the server is configured such that the second group of packets includes all the specific packets indicated by the message.

20. A system for providing content, the system comprising:

means for initiating transmission of an intended group of packets, the intended group of packets including a set of data and error-correcting information for the set of data;

means for receiving an indication of at least some data, of the set of data, that failed to be correctly received at a receiver; and

means for, in response to the indication, retransmitting a second group of packets, the second group of packets comprising less than all data, of the set of data, that failed to be correctly received at the receiver;

wherein less than all data that failed to be correctly received at the receiver is retransmitted in the retransmitting step, and the receiver will be able to obtain the all data, of the set of data, that failed to be correctly received at the receiver by performing error correction on the retransmitted second group of packets, once received, and correctly received portions of the intended group of packets, as received from the transmission that was initiated in the initiating step.

21. A system for receiving content, including video content, the system comprising:

means for receiving packets from a multicasted group of packets, wherein the multicasted group of packets include data and error-correction information for the data;

means for, if packets received without error in the receiving step include less than all the data, whereby some of the data has been lost, hereinafter referred to as lost data;