Method and system for providing a maximum channel capacity in a wavelength division multiplexing transmission system

Patent metadata

Field	Value
Publication number	US-2022353003-A1
Application number	US-202117237966-A
Country	US
Kind code	A1
Filing date	Apr 22, 2021
Priority date	Apr 22, 2021
Publication date	Nov 3, 2022
Grant date	—

Abstract

A method for providing a maximum channel capacity per optical channel in an optical wavelength division multiplexing, WDM, transmission system is described. The WDM transmission system includes transceivers using multiple optical channels in a WDM channel grid to transport optical signals modulated with a modulation format with a signal symbol rate, SR, via an optical transmission link, OTL, along an optical path from a transmitting transceiver to a receiving transceiver. A channel capacity of the optical channel is maximized while a calculated channel margin, CM, is maintained above a preset minimal channel margin value.

First claim

What is claimed is:

1 . A method for providing a maximum channel capacity per optical channel in an optical wavelength division multiplexing, WDM, transmission system with transceivers using multiple optical channels in a WDM channel grid to transport optical signals modulated with a modulation format with a signal symbol rate, SR, via an optical transmission link, OTL, along an optical path from a transmitting transceiver to a receiving transceiver,
wherein a channel capacity of the optical channel is maximized while a calculated channel margin, CM, is maintained above a preset minimal channel margin value.

2 . The method according to claim 1 wherein the channel margin, CM, is calculated based on a system performance parameter, Q, or calculated based on another performance metric which depends on the signal symbol rate, SR, and a bits per symbol rate parameter, k, of the used modulation format and/or depends on a link effective bandwidth.

3 . The method according to claim 1 wherein the system performance parameter, Q, of the WDM transmission system comprises a derivative of a bit error ratio, BER, or a derivative of another performance metric, including in particular a pre-FEC BER or a Signal-to-Noise Ratio, SNR, measured for the respective optical channel.

4 . The method according to claim 1 wherein the optical signal transported within the optical channel via the optical transmission link, OTL, is modulated with a quadrature amplitude modulation, QAM, format or with a probabilistically-shaped QAM format.

5 . The method according to claim 1 wherein a signal optical power, P, of the optical signal transported within the respective optical channel via the optical transmission link, OTL, is optimized on the basis of a link generalized optical signal noise ratio, GOSNR, wherein the generalized optical signal noise ratio, GOSNR, representing the noise related impairments of the optical transmission link, OTL, is defined as a ratio between the signal optical power of the optical signal launched by the transmitting transceiver of the optical transmission link, OTL, into the optical path and the accumulated noise along the optical path of the optical transmission link, OTL, including amplified spontaneous emission, ASE, noise generated by optical amplifiers represented by a cumulative ASE optical power, P ASE, link , and noise due to fiber nonlinearities, NLI, accumulated over link spans of the optical transmission link, OTL, and represented by a cumulative NLI optical power, P NLI, link , wherein the generalized optical signal noise ratio, GOSNR, is maximized for each link span of the optical transmission link, OTL, to optimize the signal power of the optical signal transported within the respective optical channel along the optical path of the optical transmission link, OTL, wherein a maximum generalized optical signal noise ratio of the optical transmission link, OTL, is obtained by summation over the maximized generalized optical signal noise ratios, GOSNR, over all link spans along the optical path of the respective optical transmission link, OTL.

6 . The method according to claim 1 wherein a link effective bandwidth, BW, of the optical transmission link, OTL, is calculated which represents the passband-filtering related impairments caused by optical filters provided along the optical path of the optical transmission link, OTL.

7 . The method according to claim 6 wherein the link effective bandwidth, BW, of the optical transmission link, OTL, is calculated by multiplying filter functions of link cascaded WSS modules and/or optical filters provided along the optical path of the respective optical transmission link, OTL.

8 . The method according to claim 1 wherein the system performance parameter, Q, of the optical WDM transmission system which depends on the link effective bandwidth, BW, of the optical transmission link, OTL, representing the passband-filtering related impairments of the optical transmission link, OTL, and which depends on the generalized optical signal noise ratio, GOSNR, representing the noise related impairments of the optical transmission link, OTL, is optimized iteratively until the calculated channel margin, CM, is equal or larger than the preset channel margin.

9 . The method according to claim 1 wherein an initial value, SR 0 , of the signal symbol rate, SR, of the optical signal transported within the optical channel via the optical transmission link, OTL, is preset and used to maximize the channel capacity of the optical channel.

10 . The method according to claim 1 wherein a channel frequency slot, Δf, forming a frequency spectrum range assigned to an optical channel in the WDM channel grid of the WDM transmission system is preset.

11 . The method according to claim 10 wherein the initial value, SR 0 , of the signal symbol rate, SR, is set based on a preset channel guard band defined as the difference between the channel frequency slot and the signal symbol rate, SR.

12 . The method according to claim 1 wherein the channel capacity of the optical channel is maximized to provide a maximum channel capacity during a design phase where the optical WDM transmission system is planned or wherein the channel capacity of the optical channel is maximized to provide a maximum channel capacity during a turn-up procedure to establish the optical channel via the optical transmission link, OTL, in the optical WDM transmission system deployed in the field.

13 . The method according to claim 1 wherein the optical signal transported within the optical channel along the optical transmission link, OTL, comprises a digital bit stream.

14 . The method according to claim 13 wherein a forward error correction, FEC, overhead, OH, is added at the transmitting transceiver to the digital bit stream which is transmitted by the transmitting transceiver via the optical transmission link, OTL, to a receiving transceiver to provide FEC functionality at the receiving transceiver.

15 . The method according to claim 14 wherein the bit error ratio, pre-FEC BER, of an optical channel is measured at the receiving transceiver of the optical transmission link, OTL, before forward error correction, FEC, processing to derive the system performance parameter, pre-FEC Q, of the WDM transmission system for the respective optical transmission link, OTL from the measured pre-FEC BER, wherein the derived system performance parameter, pre-FEC Q, is used to compute a maximum channel capacity for the respective optical channel.

16 . A wavelength division multiplexing, WDM, system comprising optical channels in a WDM channel grid used to transport with a signal symbol rate, SR, optical signals each modulated with a modulation format via an optical transmission link, OTL, along a signal path from a transmitting transceiver to a receiving transceiver of the WDM system and comprising a controller adapted to maximize a channel capacity for each optical channel while a calculated channel margin, CM, is maintained above a preset minimal channel margin value.

17 . The wavelength division multiplexing, WDM, system according to claim 16 wherein the channel margin, CM, is calculated based on a system performance parameter, Q, or based on another performance metric which depends on the signal symbol rate, SR, and a bits per symbol parameter, k, of the modulation format and/or depend on a link effective channel bandwidth until the calculated channel margin, CM, of the optical channel is equal or larger than a preset channel margin target.

18 . The wavelength division mult

Assignees

• Adva Optical Networking Se

Inventors

• Burtsev Sergey
• Searcy Steven
• Richter Thomas
• Tibuleac Sorin

Classifications

• H04B10/07953 Primary

  Monitoring or measuring OSNR, BER or Q · CPC title

• H04J14/0227 Primary

  Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation · CPC title

• H04J14/0271

  Impairment aware routing · CPC title

• H04J14/026

  using WDM channels of different transmission rates · CPC title