(Continuation of Questions 18 and 19/15)
Background and justification
The demand for transmission capacity has been rapidly
increasing due to the rapid evolution towards a packet based
network infrastructure (Internet). Optical fibre submarine cable
systems form an essential part of the worldwide communication
networks and are affected by such an increase in demand.
Transmission systems satisfying this demand could be realized
using a combination of Time Division Multiplexing (TDM),
wavelength division multiplexed (WDM), and optical amplifying
techniques (in-line optical amplifier, post amplifier,
pre-amplifier, remote amplification, etc.). Moreover, as the
transmission capacity increases, protection mechanisms, both from
a mechanical (submarine cables) and system perspective (e.g. ring
structure), become more important to improve system reliability
and availability.
Responsibility under this Question includes the following
Recommendations:
G. 971: General features of optical fibre submarine cable
systems
G. 972: Definition of terms relevant to optical fibre
submarine cable systems
G. 973: Characteristics of repeaterless optical fibre
submarine cable systems
G. 974: Characteristics of regenerative optical fibre
submarine cable systems
G. 975: Forward error correction for submarine systems
G. 976: Test methods applicable to optical fibre submarine
cable systems.
G. 977: Characteristics of optically amplified optical
fibre submarine cable systems
Question
- How should Recommendations G. 971, G. 972, G. 973, G.975, G.
976 and G. 977 be amended or restructured in order to ease their
use?
- What new transmission techniques should be recommended to
increase transmission capabilities of optical fibre submarine
cable systems?
- What new components and subsystems (fibre, component, etc.)
should be utilized to improve system capacity and reliability?
- What mechanical protection and system protection mechanisms
should be recommended for high capacity submarine cable systems to
improve systems reliability/availability?
- What new Recommendations are necessary?
Study items
Study items to be considered include:
- Transmission characteristics of optical fibre submarine cable
systems
- Interface characteristics of optical fibre submarine cable
systems
- Mechanical characteristics of the submarine portion of
optical fibre submarine cable systems
- Test methods
- Evolution of submarine systems to higher bit-rates, including
the effects of chromatic dispersion, polarization mode
dispersion, and optical fibre nonlinearities
- Adoption of wavelength-division multiplexing/ demultiplexing
techniques
- FEC (Forward Error Correction) for high bit rate DWDM
submarine systems
- Introduction of other types of fibre amplifiers or
semiconductor amplifiers operating at different wavelengths
- Use of branching devices in submarine networks
- Availability and reliability
- Operations and maintenance
- Interface compatibility of submarine and terrestrial systems
- Mechanical and systems level protection mechanisms
- Optical submarine systems based on soliton transmission
techniques
Specific tasks
- Revision and/or restructuring G. 971, G. 972, G.973, G. 975,
G. 976, and G.977 (2004)
- Consider development of a new Recommendation to serve as a
FEC standard for high bit rate DWDM submarine cable systems and
in the same time keeping Rec. G.975 (Forward Error Correction
for Submarine Systems) as reference for legacy submarine cable
systems that use FEC code RS (225, 239) (2004)
- Continue updating the Appendix/G. 971 regarding data on cable
ships and submersible equipment (as required)
Relationships
- Other relevant Questions of SG 15 on optical transmission
systems
- ITU-T SG 6 on other types of underwater cables (e.g.
marinized terrestrial cables)
- ITU-T SG 13 on error performance
- IEC SC86 on fibre reliability and on underwater cables
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