scope:

The present Recommendation is primarily concerned with the implementation of a Forward Error Correction (FEC) function in the multigigabit-per-second optical fibre submarine cable systems. The applications being addressed in this Recommendation are both optically amplified repeatered systems and repeaterless optical systems (ITU-T G.973 [3]). The use of this FEC function in submarine terminal transmission equipments (TTEs) should not be considered as mandatory.

It is not the intention of this Recommendation to pursue the transverse compatibility of the system. Therefore the selection of the FEC frame structures described in this Recommendation is a matter of joint engineering.

The transmission data rates under consideration in this Recommendation are 2.5 Gbit/s STM-16 (ITU-T G.707 [1]) and integer multiples of 2.5 Gbit/s (interleaved STM-16 tributaries).

Clause 5 presents the main features of the FEC function implemented in the submarine systems, and in particular the error monitoring facility.

Clause 6 provides the definition of the forward error correction algorithm to be used, which is a Reed-Solomon code, and gives guidelines for the implementation of this algorithm in the submarine Terminal Transmission Equipments (TTEs).

Clause 7 is dedicated to the measurement of the performance of this Reed-Solomon code and the expected gain on the optical transmission power budget.