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US 9,673,907 B1Granted
Constellation shaping of modulation formats for optical communication systems
AssigneeFujitsu Limited
InventorsOlga Vassilieva, Inwoong Kim, Tadashi Ikeuchi
Life of this patent
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Abstract
Methods and systems for constellation shaping of modulation formats in optical communication systems may involve enabling an optical transport network to activate/deactivate constellation shaping on a per channel basis for a given optical path using universal programmable transceivers. Then, constellation shaping may be activated to increase the reach of optical channels by improving signal-to-noise ratio over the optical path.
Claims24
A method for constellation shaping of modulation formats in optical transport networks, the method comprising:
- receiving path information specifying attributes of an optical path in an optical network, wherein the path information includes a distance of the optical path and a number of optical channels transmitted over the optical path;
- based on the path information, identifying a first modulation format for an optical channel transmitted over the optical path, wherein the first modulation format has a uniform distribution of constellation points in the complex plane;
- when a first bit error rate (BER) for the optical channel using the first modulation format over the distance exceeds a threshold value, identifying a second modulation format for the optical channel, wherein the second modulation format has a non-uniform distribution of constellation points in the complex plane, and wherein the second modulation format results in a second BER for the distance that does not exceed the threshold value;
- sending a first command to an optical transmitter for the optical path to use the second modulation format for the optical channel;
- sending a second command to an optical receiver for the optical path to use the second modulation format for the optical channel;
- and
- transmitting the optical channel over the optical path using the second modulation format.
4 more elements
A method for constellation shaping of modulation formats in optical transport networks, the method comprising:
- monitoring a first bit error rate (BER) of an optical channel transmitted over an optical path in an optical network using a first modulation format over a distance, wherein the first modulation format has a uniform distribution of constellation points in quadrature space;
- when the first BER for the optical channel over the distance exceeds a threshold value, identifying a second modulation format for the optical channel, wherein the second modulation format has a non-uniform distribution of constellation points in quadrature space, and wherein the second modulation format results in a second BER for the distance that does not exceed the threshold value;
- sending a first command to an optical transmitter for the optical path to use the second modulation format for the optical channel;
- sending a second command to an optical receiver for the optical path to use the second modulation format for the optical channel;
- and
- transmitting the optical channel over the optical path using the second modulation format.
3 more elements
An optical transport network for constellation shaping of modulation formats, the optical transport network comprising:
- an optical transmission path, including an optical transmitter and an optical receiver;
- and
- a network management system enabled to:
- receive path information specifying attributes of an optical transmission path, wherein the path information includes a distance of the optical path and a number of optical channels transmitted over the optical transmission path;
- based on the path information, identifying a first modulation format for an optical channel, wherein the first modulation format has a uniform distribution of constellation points in the complex plane;
- when a first bit error rate (BER) for the optical channel using the first modulation format for the distance exceeds a threshold value, identifying a second modulation format for the optical channel, wherein the second modulation format has a non-uniform distribution of constellation points in the complex plane, and wherein the second modulation format results in a second BER for the optical channel over the distance that does not exceed the threshold value;
- sending a first command to the optical transmitter to use the second modulation format for the optical channel;
- and
- sending a second command to the optical receiver to use the second modulation format for the optical channel.
6 more elements
An optical transport network for constellation shaping of modulation formats, the optical transport network comprising:
- an optical transmission path, including an optical transmitter and an optical receiver;
- and
- a network management system enabled to:
- monitor a first bit error rate (BER) of an optical channel transmitted over the optical transmission path using a first modulation format over a distance, wherein the first modulation format has a uniform distribution of constellation points in quadrature space;
- when the first BER for the optical channel over the distance exceeds a threshold value, identifying a second modulation format for the optical channel, wherein the second modulation format has a non-uniform distribution of constellation points in quadrature space, and wherein the second modulation format results in a second BER for the optical channel over the distance that does not exceed the threshold value;
- sending a first command to the optical transmitter to use the second modulation format for the optical channel;
- and
- sending a second command to the optical receiver to use the second modulation format for the optical channel.
5 more elements
Dependencies are inferred from the claim text.