Error correction apparatus and method

• US 7,506,235 B2
• Filed: 10/13/2005
• Issued: 03/17/2009
• Est. Priority Date: 05/30/2003
• Status: Expired due to Fees

• Current Assignee: Wegener Communications Incorporated
• Original Assignee: Wegener Communications Incorporated
• Inventors: Merritt, David
• Primary Examiner(s): Baker, Stephen M.
• Application Number:
  US11/249,780
• Publication Number:
  US 20060085724A1
• Time in Patent Office: 1,251 Days
• Field of Search: 714/748
• US Class Current: 714/748
• CPC Class Codes: H04L 1/1614 using bitmaps

Abstract

A system, method and data structure for error correction for use in the transmission of content data distribution networks uses a compressed memory, for example a bitmap, to identify portions of transmitted content data files where transmission errors have occurred. The error memory, is used to generate an error status report that is returned to a transmission controller via a low bandwidth back channel, for example the Internet. The information in multiple error status reports is aggregated by the control system of the transmitter and used to re-transmit those portions of previously transmitted content data files that were not properly received due to error. By re-transmitting only the data packets of the transmitted content data files that contain errors, overall transmission speed is increased and bandwidth usage is conserved.

Claims

1. An error status report data structure for reporting errors in transmission of content data files comprised of multiple packets, said error status report data structure comprising:

a file signature, said file signature corresponding to a content data file;

a first of a range identifier, said first of a range identifier corresponding to a first missing block of the content data file in a range of missing blocks;

a last of a range identifier, said last of a range identifier corresponding to a last missing block of a content data file in the range of missing blocks;

said first of range identifier and said last of range identifier being associated with each other in said error status report data structure;

a byte offset, said byte offset corresponding to a byte containing a missing block;

a length indicator, said length indicator corresponding to a length of a plurality of missing blocks;

a plurality of markings, said markings corresponding to a plurality of missing blocks;

said byte offset, said length indicator and said plurality of markings being associated with each other in said error status report data structure;

said association of said first of a range identifier and said last of a range identifier being used for a first number of marks corresponding to missing blocks and said association of said byte offset, said length indicator and said plurality of markings corresponding to a second number of marks corresponding to missing blocks; and

wherein a data structure is configured in a computer readable medium.

2. The data structure of claim 1 wherein said first number of marks is one byte or more.

3. The data structure of claim 1 wherein said first number of marks and said second number of marks are configurable.

4. The data structure of claim 1 wherein said markings are a bitmap.

5. The data structure of claim 1 wherein at least one said association of said first of a range identifier and said last of a range identifier, or said association of said byte offset, said length indicator and said plurality of markings, is executed using a method selected from the group consisting of:

Huffman coding, wavelet based compression, LZW, assigning symbols to groups of errors and run length encoding.

6. The data structure of claim 1 wherein said data structure includes an error report identifier, said error report identifier associating said data structure with an error report data structure configured in a remote uplink.

7. The data structure of claim 1 further comprising a single missing block indicator.

8. The data structure of claim 1 wherein said missing blocks include invalid packets.

9. The data structure of claim 1 wherein said missing blocks include content data packets never received.

10. The data structure of claim 1 wherein said missing blocks include data packets received but containing errors.

11. The data structure of claim 1 wherein said data structure comprises a memory.

12. The data structure of claim 1 wherein said data structure comprises a non-volatile memory.

13. An integrated receiver/decoder for receiving transmissions of content data files, said receiver/decoder comprising:

a long term memory configured to store valid packets received, the valid packets comprising at least a part of a transmitted content data file;

a short term memory configured to store identifiers for invalid packets;

a data packet file receipt processor, said file receipt processor being configured to store valid packets received in said long term memory and to identify invalid packets in said short term memory;

an error report processor, said error report processor being configured to be able to compress said short term memory both by identifying a consecutive range of invalid packets and by reproducing a plurality of markings, said plurality of markings corresponding to a consecutive plurality of invalid packets, said plurality of markings being located in a content data transmission with a byte offset and a length indicator

a return path processor, said return path processor being configure to encapsulate said short term memory in an email, said email being adapted for transmission through a computer network to a remote uplink from which said content data files have been received.

14. The apparatus of claim 13 wherein said content data files are MPEG files.

15. The apparatus of claim 13 wherein said consecutive range is of a configurable length.

16. The apparatus of claim 13 wherein said plurality of markings is of a configurable length.

17. The apparatus of claim 13 wherein said compression of said short term memory is a bitmap.

18. The apparatus of claim 13 wherein said compression of said short term memory is executed using a method selected from the group consisting of:

Huffman coding, wavelet based compression, LZW, assigning symbols to groups of errors and run length encoding.

19. The apparatus of claim 13 wherein said error report processor is further configured to include a single invalid packet indicator in said compression of said short term memory.

20. The apparatus of claim 13 wherein the invalid packets include content data packets never received.

21. The apparatus of claim 13 wherein the invalid packets include packets received but containing errors.

22. The apparatus of claim 13 wherein said short term memory is a non-volatile memory.