Forward error correction (FEC) based on SONET/SDH framing
First Claim
Patent Images
1. A method for performing forward error correction in a SONET system, wherein a coding scheme associated with the forward error correction has a coding factor of (n/k) and an interleaving depth, the method comprising:
- receiving a data string to be coded, the data string having a number of bytes;
dividing the number of bytes by the interleaving depth thereby producing B byte chunks;
segmenting each byte chunk based on k of the coding factor thereby producing a number of segments;
encoding each segment in accordance with the coding scheme thereby producing consecutive FEC sub-frames, each FEC sub-frame including non-parity bytes and parity bytes;
concatenating separately the non-parity bytes and corresponding parity bytes of (B/k) consecutive FEC sub-frames thereby producing rows of a FEC frame having X rows, where X is equal to the interleaving depth; and
consecutively interleaving each row of the FEC frame thereby producing a coded data string.
5 Assignments
0 Petitions
Accused Products
Abstract
Techniques for applying FEC to optical signals such as synchronous transport signal level N SONET frames, as well as other frame structures (e.g., synchronous transport module level N SDH frames) are provided.
-
Citations
21 Claims
-
1. A method for performing forward error correction in a SONET system, wherein a coding scheme associated with the forward error correction has a coding factor of (n/k) and an interleaving depth, the method comprising:
-
receiving a data string to be coded, the data string having a number of bytes;
dividing the number of bytes by the interleaving depth thereby producing B byte chunks;
segmenting each byte chunk based on k of the coding factor thereby producing a number of segments;
encoding each segment in accordance with the coding scheme thereby producing consecutive FEC sub-frames, each FEC sub-frame including non-parity bytes and parity bytes;
concatenating separately the non-parity bytes and corresponding parity bytes of (B/k) consecutive FEC sub-frames thereby producing rows of a FEC frame having X rows, where X is equal to the interleaving depth; and
consecutively interleaving each row of the FEC frame thereby producing a coded data string. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
scrambling the coded data string; and
transmitting the scrambled coded data string.
-
-
10. The method of claim 1 further comprising:
in response to there being one or more additional data strings to be coded, repeating the method for each additional data string.
-
11. The method of claim 1 wherein the SONET system defines a number of operatively coupled functional layers including a line layer, a section layer, and a FEC layer, and the method operates in the FEC layer.
-
12. The method of claim 11 wherein the section and line layers are associated with transport overhead bytes, and each transport overhead byte is associated with generation and insert/drop functionality that is executed before the encoding of the FEC layer.
-
13. The method of claim 11 wherein the section layer is associated with an overhead byte B1 that is used for a section error monitoring function, and the line layer is associated with an overhead byte B2 that is used for a line error monitoring function, and both bytes B1 and byte B2 are each calculated using a BIP-8 algorithm before the encoding of the FEC layer.
-
14. The method of claim 11 wherein the SONET system has a transmitting node and a receiving node communicatively coupled by a transmission medium, and at the receiving node, transport overhead bytes B1 and byte B2 are each calculated using a BIP-8 algorithm after a FEC decoding process corresponding to the encoding of the FEC layer has been performed.
-
15. The method of claim 1 wherein the SONET system defines a number of operatively coupled functional layers including a line layer and a combined section &
- FEC layer, and the method operates in the section &
FEC layer.
- FEC layer, and the method operates in the section &
-
16. The method of claim 15 wherein the section &
- FEC layer is associated with transport overhead bytes, and each transport overhead byte is associated with generation and insert/drop functionality that is executed after the encoding of the section &
FEC layer.
- FEC layer is associated with transport overhead bytes, and each transport overhead byte is associated with generation and insert/drop functionality that is executed after the encoding of the section &
-
17. The method of claim 15 wherein the section &
- FEC layer is associated with an overhead byte B1 that is used for a section error monitoring function, and byte B1 is calculated using a BIP-8 algorithm after the encoding of the section &
FEC layer.
- FEC layer is associated with an overhead byte B1 that is used for a section error monitoring function, and byte B1 is calculated using a BIP-8 algorithm after the encoding of the section &
-
18. The method of claim 15 wherein the SONET system has a transmitting node and a receiving node communicatively coupled by a transmission medium, and at the receiving node, transport overhead byte B1 is calculated using a BIP-8 algorithm before a FEC decoding process corresponding to the encoding of the FEC layer has been performed.
-
19. A method for performing forward error correction in one of a SONET system or an SDH system, wherein a coding scheme associated with the forward error correction has a coding factor of (n/k) and an interleaving depth, the method comprising:
-
receiving a data string to be coded, the data string having a number of bytes;
dividing the number of bytes by the interleaving depth thereby producing B byte chunks;
segmenting each byte chunk based on k of the coding factor thereby producing a number of segments;
encoding each segment in accordance with the coding scheme thereby producing consecutive FEC sub-frames, each FEC sub-frame including non-parity bytes and parity bytes;
concatenating separately the non-parity bytes and corresponding parity bytes of (B/k) consecutive FEC sub-frames thereby producing rows of a FEC frame having X rows, where X is equal to the interleaving depth; and
consecutively interleaving each row of the FEC frame thereby producing a coded data string.
-
-
20. A method for performing forward error correction in a SONET/SDH system, wherein a coding scheme associated with the forward error correction has a coding factor of (n/k) and an interleaving depth, the method comprising:
-
receiving a coded data string forming a row of a SONET/SDH-FEC frame;
estimating bit error using a BIP-8 algorithm thereby characterizing transmission line conditions without the benefit of the forward error correction;
de-interleaving the coded data string thereby creating X rows of a FEC frame, where X equals the interleaving depth;
decoding each FEC frame in accordance with the coding scheme thereby producing decoded data stings; and
interleaving the decoded data strings thereby forming a row of a SONET/SDH frame.
-
-
21. A method for performing forward error correction in a SONET/SDH system, wherein a coding scheme associated with the forward error correction has a coding factor of (n/k) and an interleaving depth, the method comprising:
-
receiving a coded data string forming a row of a SONET/SDH-FEC frame;
de-interleaving the coded data string thereby creating X rows of a FEC frame, where X equals the interleaving depth;
decoding each FEC frame in accordance with the coding scheme thereby producing decoded data stings;
estimating bit error using a BIP-8 algorithm thereby characterizing transmission line conditions as improved by the forward error correction; and
interleaving the decoded data strings thereby forming a row of a SONET/SDH frame.
-
Specification