Error Correction Apparatus and Method

• US 20080228787A1
• Filed: 02/25/2008
• Published: 09/18/2008
• Est. Priority Date: 05/30/2003
• Status: Active Grant

• Current Assignee: Wegener Communications, Inc. (Wegener Corporation)
• Original Assignee: Wegener Communications, Inc. (Wegener Corporation)
• Inventors: Merritt, David
• Granted Patent: US 7,937,638 B2
• Time in Patent Office: Days
• US Class Current: 707/100
• 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;

said association of said first of a range identifier and said last of a range identifier being used for a number of marks corresponding to missing blocks; and

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

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

3. The data structure of claim 1 wherein said number of marks is configurable.

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

5. The data structure of claim 1 wherein said association of said first of a range identifier and said last of a range identifier 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 at least one of invalid packets, content data packets never received, and data packets received but containing errors.

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

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

11. 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 by identifying a consecutive range of invalid packets.

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.

12. The apparatus of claim 11 wherein said consecutive range is of a configurable length.

13. The apparatus of claim 11 wherein said compression of said short term memory is a bitmap.

14. The apparatus of claim 11 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.

15. The apparatus of claim 11 wherein said error report processor is further configured to include a single invalid packet indicator in said compression of said short term memory.

16. The apparatus of claim 11 wherein the invalid packets include at least one of an invalid packet, content data packets never received, and packets received but containing errors.

17. The apparatus of claim 11 wherein said short term memory is a non-volatile memory.

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

a file signature;

said file signature corresponding to a content data file 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 byte offset, said length indicator and said plurality of markings corresponding to a number of marks corresponding to missing blocks; and

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