Self synchronous scrambler apparatus and method for use in dense wavelength division multiplexing
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorBrian Sweeney
Life of this patent
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Abstract
A method employing a self-synchronous scrambler for transforming an arbitrary bit-stream into a bit-stream suitable for input to a DWDM network, and for reconstituting the original bit-stream from the transformed bit-stream. This method enables DWDM network equipment to properly transport data independent of the bit-stream characteristics and line encoding of the data. The self-synchronous scrambler of the present invention equalizes the number of “1”s and ‘0”s in an input bit-pattern over time periods of a few bit-clock periods, thus making it suitable for transport over a DWDM channel and providing for the recovery of the original bit-pattern from the scrambled pattern.
Claims21
A method for transforming and communicating an arbitrary bit-stream data into a bit-stream suitable for input to a dense wavelength division multiplexing (DWDM) network, the method comprising the steps of:
- receiving an optically encoded digital data stream;
- converting the encoded digital data stream to a binary data stream;
- applying error correction to the binary data stream to generate an error correcting code over a fixed number of input bits to correct for error multiplication;
- placing the error correcting code into the binary data stream to produce a bit-serial data stream;
- applying a self-synchronous scrambler on the bit-serial data stream, the scrambler having an executable logic to equalize “1”s and “0”s, in the arbitrary bit-stream data, over a plurality of bit-clock periods to produce scrambled bit-stream data;
- encoding the scrambled bit-stream data;
- and
- transmitting the encoded scrambled bit-stream data independent of its bit-stream characteristics and line coding.
In a digital data communications system having a transmitting station, a receiving station, and a communication medium communicatively coupling the transmitting and receiving stations, a method for transforming an arbitrary bit-stream data from the transmitting station to a bit-stream suitable for input to the data communications system, the method comprising:
- receiving an optically encoded digital data stream by a DWDM input terminal unit;
- generating a bit-serial data stream from optically encoded digital data received from the transmitting station;
- applying a self-synchronous scrambler on the bit-serial data stream having an executable logic to equalize “1”s and “0”s in an input bit-pattern over time periods of several bit-clock periods and producing scrambled bit-stream data;
- and
- encoding and transmitting the scrambled bit-stream data independent of its bit-stream characteristics and line coding.
A method for transforming an arbitrary bit-stream into a bit-stream suitable for transmission on a digital data communications network and reconstituting the arbitrary bit-stream from transformed bit-stream, the method comprising:
- converting an input data stream into a binary data stream;
- generating an error correcting code over a fixed number of input bits to correct for error multiplication;
- placing the error correcting code into the binary data stream to produce a bit-serial data stream;
- applying a self-synchronous scrambler on the bit-serial data stream, the scrambler having an executable logic to equalize “1”s and “0”s in an input bit-pattern over a plurality of bit-clock periods to produce a scrambled bit-stream;
- and
- encoding and transmitting the scrambled bit-stream data independent of its bit-stream characteristics and line coding.
A digital data communications system for transmitting an arbitrary input bit-stream data from a source station to a destination station via an optical communications medium communicatively coupling said source and destination stations, the digital data communications system comprising:
- a DWDM input unit receiving the arbitrary data stream from the source station, said DWDM input unit including
- an optical-to-electrical conversion unit for converting the arbitrary input bit-stream data into binary data stream;
- a self-synchronous scrambler executing a logic to equalize the number of “1”s and “0”s, in the binary data stream, over a plurality of bit-clock periods to produce a scrambled data stream;
- and
- an electrical-to-optical conversion unit for encoding and transmitting the scrambled data stream via the optical communication medium, wherein said scrambler enables said DWDM input unit to transport the arbitrary input bit-stream data independent of its bit-stream characteristics and line coding;
- and
- a DWDM output unit for receiving the scrambled data stream transmitted via said optical communications medium, said DWDM output unit including a self-synchronous descrambler executing a logic that is opposite to the logic executed by said self-synchronous scrambler.
A method for transforming an arbitrary bit-stream into a bit-stream suitable for input to a dense wavelength division multiplexing (DWDM) network, the method comprising:
- receiving an optically encoded digital data stream by an optical input;
- converting the encoded digital data stream to a binary data stream;
- adding fixed-length overhead fields to the binary data stream to produce a bit-serial data stream;
- applying a self-synchronous scrambler on the bit-serial data stream, the scrambler executing a logic to equalize “1”s and “0”s in an input bit-pattern over a plurality of bit-clock periods to produce scrambled bit-stream data;
- generating and applying error correction code (ECC) to the scrambled bit-stream data to correct single bit-errors;
- placing the scrambled bit-stream data and error correction code into a variable length frame having frame synchronization bytes to produce a scrambled bit-stream data with ECC;
- and
- encoding and transmitting the scrambled bit-stream data with ECC using optical encoding on a carrier suitable for optical multiplexing, wherein the scrambled bit-stream data with ECC is transmitted independent of its bit-stream characteristics and line coding.
Dependencies are inferred from the claim text.