Requesting additional forward error correction

• US 20080028279A1
• Filed: 07/07/2006
• Published: 01/31/2008
• Est. Priority Date: 07/07/2006
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Scientific-Atlanta Incorporated (Cisco Systems, Inc.)
• Inventors: Ver Steeg, William C.
• Granted Patent: US 7,774,672 B2
• Time in Patent Office: Days
• US Class Current: 714/776
• CPC Class Codes: H04L 1/1819 with retransmission of additional or different redundancy
• CPC Class Codes: H04L 1/1829 Arrangements specially adapted for the receiver end
• CPC Class Codes: H04L 1/1867 Arrangements specially adapted for the transmitter end
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 2001/0097 Relays

Abstract

Systems and methods are disclosed herein for requesting additional forward error correction, when needed, in a communication system. In one exemplary embodiment, among others, a method includes receiving a first set of data packets and a first amount of forward error correction (FEC) from an upstream transmitting device. The method also includes determining whether or not the first amount of FEC is sufficient to correct any detected errors with respect to the data packets. Then, an error indication is transmitted to the upstream transmitting device when the first amount of FEC is not sufficient to correct the detected errors.

Claims

1. A method performed in a communication system, the method comprising:

receiving a first set of data packets and a first amount of forward error correction (FEC) from an upstream transmitting device;

determining whether or not the first amount of FEC is sufficient to correct any detected errors with respect to the data packets; and

transmitting an error indication to the upstream transmitting device when the first amount of FEC is not sufficient to correct the detected errors.

2. The method of claim 1, further comprising:

correcting any detected errors when the first amount of FEC is sufficient.

3. The method of claim 1, further comprising:

receiving an additional amount of FEC from the upstream transmitting device after transmitting an error indication to the upstream transmitting device.

4. The method of claim 3, further comprising:

correcting the detected errors using the first amount of FEC and the additional amount of FEC.

5. The method of claim 4, wherein correcting the detected errors includes restoring the data packets to their condition before being transmitted by the upstream transmitting device.

6. The method of claim 4, further comprising:

transmitting the corrected data packets to a downstream device.

7. The method of claim 6, further comprising:

transmitting a third amount of FEC with the corrected data packets.

8. The method of claim 7, wherein the third amount of FEC is calculated after the data packets are corrected.

9. The method of claim 7, wherein the third amount of FEC is taken from the first amount of FEC and the additional amount of FEC.

10. The method of claim 1, wherein determining whether or not the first amount of FEC is sufficient includes determining whether the number of errors detected in the data packets exceeds a predetermined threshold.

11. The method of claim 1, wherein transmitting the error indication includes transmitting a signal representing a number of the data packets that were dropped.

12. The method of claim 1, wherein transmitting the error indication includes transmitting a signal representing specific data packets that were dropped.

13. The method of claim 1, further comprising:

after transmitting the error indication to the upstream transmitting device, receiving a second set of data packets from the upstream transmitting device, wherein the second set of data packets represent data packets that were transmitted with the first set of data packets but were dropped.

14. The method of claim 1, further comprising:

detecting errors by analyzing a header associated with the received first set of data packets.

15. A receiver located in a communication system, the receiver comprising:

an input device for receiving a stream of data packets and forward error correction (FEC) code;

a buffer for storing the received data packets and FEC code; and

a processor for determining the condition of the data packets, the processor configured to transmit a request to receive additional FEC code.

16. The receiver of claim 15, wherein the receiver is a part of an end device selected from a group consisting of a set-top box, a computer, a modem, a digital subscriber line (DSL) modem, and video acceleration module (VAM).

17. The receiver of claim 15, wherein the processor transmits the request when the received FEC code is not sufficient to handle errors in the received stream of data packets.

18. The receiver of claim 15, wherein, upon receiving additional FEC code, the processor is configured to restore the stream of data packets.

19. The receiver of claim 18, wherein the processor restores the stream of data packets using an initially received amount of FEC code, received with the stream of data packets, and the additional FEC code.

20. The receiver of claim 18, further comprising a driver configured to transmit the restored stream of data packets to a downstream device.