US 8,166,365 B2 · Cycle slip location and correction

Abstract

Methods and techniques are disclosed for correcting the effect of cycle slips in a coherent communications system. A signal comprising SYNC bursts having a predetermined periodicity and a plurality of known symbols at predetermined locations between successive SYNC bursts is received. The received signal is partitioned into data blocks. Each data block encompasses at least data symbols and a set of check symbols corresponding to the plurality of known symbols at predetermined locations between a respective pair of successive SYNC bursts in the signal. Each data block is processed to detect a cycle slip. When a cycle slip is detected, the set of check symbols of the data block are examined to identify a first slipped check symbol, and a phase correction applied to data symbols of the data block lying between the first slipped check symbol and an end of the data block.

Claims8

Dependent claims

A method of correcting an effect of cycle slips in an optical communications system, the method comprising steps of:

receiving an optical signal through the communications system, the signal comprising SYNC bursts having a predetermined periodicity and a plurality of known symbols at predetermined locations between successive SYNC bursts;
partitioning the received optical signal into data blocks, wherein each data block encompasses at least data symbols and a set of check symbols corresponding to the plurality of known symbols at predetermined locations between a respective pair of successive SYNC bursts in the optical signal;
processing each data block to detect a cycle slip, and, when a cycle slip is detected:
examining the set of check symbols of the data block to identify a first slipped check symbol;
and
applying a phase correction to data symbols of the data block lying between the first slipped check symbol and an end of the data block.

3 more elements

A coherent receiver for receiving an optical signal through an optical communications system, the coherent receiver comprising:

a detector for receiving the optical signal, the optical signal comprising SYNC bursts having a predetermined periodicity and a plurality of known symbols at predetermined locations between successive SYNC bursts;
a framer for partitioning the received optical signal into data blocks, wherein each data block encompasses at least data symbols and a set of check symbols corresponding to the plurality of known symbols at predetermined locations between a respective pair of successive SYNC bursts in the optical signal;
a decoder processing each data block to detect a cycle slip;
and,
a post processor responsive to the decoder, for processing a data block affected by a cycle slip, the post processor implementing steps of:
examining the set of check symbols of the affected data block to identify a first slipped check symbol;
and
applying a phase correction to data symbols of the affected data block lying between the first slipped check symbol and an end of the affected data block.

5 more elements

Dependencies are inferred from the claim text.

Cycle slip location and correction

Life of this patent

Cycle slip location and correction

Life of this patent

Abstract

Claims8