Apparatus for processing OTN frames utilizing an efficient forward error correction

• US 7,573,871 B2
• Filed: 12/10/2002
• Issued: 08/11/2009
• Est. Priority Date: 01/16/2002
• Status: Expired due to Fees

• Current Assignee: Optix Networks Limited
• Original Assignee: Transwitch Israel Ltd. (Transwitch Corporation)
• Inventors: Altarovici, Liviu, Moshe, Haim, Dabby, Amir, Lahav, Danny
• Primary Examiner(s): Yao, Kwang B
• Assistant Examiner(s): Tran, Tung Q
• Application Number:
  US10/499,435
• Publication Number:
  US 20050068995A1
• Time in Patent Office: 2,436 Days
• Field of Search: 370351-430
• US Class Current: 370/389
• CPC Class Codes: H04J 2203/006 Fault tolerance and recovery
• CPC Class Codes: H04J 2203/0089 Multiplexing, e.g. coding, scrambling, SONET
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085
• CPC Class Codes: H04J 3/1611 Synchronous digital hierarchy [SDH] or SONET H04J3/1664 takes precedence for interactions with OTN
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27

Abstract

An apparatus and method utilizing an efficient forward error correction (FEC), targeted for processing optical transport network (OTN) signals having transmission rates in excess of 10 Gbps. The FEC uses an advanced implementation of the Bose Chaudhuri Hocquenghem (BCH) code. The use of the BCH code for the FEC improves the performance over prior art solutions for both error correction and detection.

Claims

1. An apparatus for optical transport networks (OTNs) that enables efficient OTN frames processing and improved forward error correction (FEC), the apparatus having a line interface for interfacing with an external network and a system interface for interfacing with a client, the apparatus comprising:

a line receive unit (LRU) connected to the line interface and receiving through the line interface network OTN frames, said LRU including a Bose-Chaudhuri-Hocquenghem (BCH) decoder for performing FEC on said OTN frames using solely a BCH code, said LRU processes forward error corrected OTN frames into LRU processed network OTN frames; and

a system receive unit (SRU) connected to said LRU and the system interface, said SRU processes said LRU processed network OTN frames to generate SRU processed OTN frames; and

further transmits said SRU processed OTN frames through the system interface to the client; and

a line transmit unit (LTU) including a BCH encoder, said LTU connected through a multiplexer to said LRU and said STU, said LTU processes network and client OTN frames received respectively from said LRU and said STU into LTU BCH coded OTN frames that are being output to the network through the line interface, wherein said BCH encoder produces redundancy bits by processing at least one BCH code-word, wherein said redundancy bits are placed in a FEC area of an OTN frame.

2. The apparatus of claim 1, further comprising:

a system transmit unit (STU) connected to the client through the system interface, said STU processes client OTN frames received through said line interface into STU processed OTN frames.

3. The apparatus of claim 1, where said OTN frames are transmitted at a line rate of at least 40 Gbps.

4. The apparatus of claim 1, wherein said network OTN frames are scrambled.

5. The apparatus of claim 1, wherein said LRU further includes:

a framer for performing at least one frame alignment on at least one of said network OTN frames,

a first overhead processor for processing overheads of said network OTN frames, and

a descrambler for descrambling said network OTN frames.

6. The apparatus of claim 2, wherein said connection of said LTU through said input port to said LRU and said STU includes a connection through a multiplexer.

7. The apparatus of claim 2, wherein said LTU further includes:

a second overhead processor for processing overheads of at least one of;

said client OTN frames, and said LRU processed network OTN frames;

a framer for performing at least one frame alignment on at least one of said client OTN frames, and said LRU processed network frames; and

a scrambler for scrambling said LTU processed OTN frames.

8. The apparatus of claim 1, wherein the line and system interfaces include each an interface selected from the group consisting of a SFI-5 interface and a SFI-4 interface.