Apparatus and methods for channel allocation

Apparatus, comprising:

• a merging circuit configured to input at least an input stream A and an input stream B of sequentially ordered input data units of data encoded by a plurality of OFEC encoders, and to merge the said at least streams A and B so as to produce at least a first merged stream and a second merged stream of sequentially ordered output data units;
• and
• an allocating circuit configured to allocate one merged stream to an optical subcarrier SC0 of an optical communication system and to allocate another merged stream to an optical subcarrier SC1 of an optical communication system having two polarization channels, wherein:
• the optical subcarriers SC0 and SC1 belong to a plurality of at least two optical subcarriers;
• each of the input data units comprises one or more blocks of encoded data;
• the merging circuit is configured to assign input data units from the respective input streams to the respective merged streams by round robin distribution;
• the merging circuit is further configured, for each respective merged stream, to generate output data units by merging input data units assigned to that merged stream, such that each output data unit for that merged stream comprises the encoded data blocks of one input data unit from each of the respective input streams;
• and
• the allocating circuit is configured to periodically alternate the allocating of merged streams between a first allocation scheme in which the first merged stream is allocated to SC0 and the second merged stream is allocated to SC1, and a second allocation scheme in which the first merged stream is allocated to SC1 and the second merged stream is allocated to SC0, whereby for each OFEC encoder of said OFEC encoder plurality, a same number of bits is allocated to each subcarrier of the subcarrier plurality, and a same number of bits is allocated to each of the two polarization channels.

Apparatus, comprising:

• a merging circuit configured to input at least an input stream A and an input stream B of sequentially ordered input data units of data encoded by a plurality of OFEC encoders, and to merge the said at least streams A and B so as to produce at least a first merged stream and a second merged stream of sequentially ordered output data units;
• and
• an allocating circuit configured to allocate one merged stream to an optical subcarrier SC0 of an optical communication system and to allocate another merged stream to an optical subcarrier SC1 of an optical communication system having two polarization channels, wherein:
• the optical subcarriers SC0 and SC1 belong to a plurality of at least two optical subcarriers;
• each of the input data units comprises one or more blocks of encoded data;
• the merging circuit is configured to assign input data units from the respective input streams to the respective merged streams by round robin distribution;
• the merging circuit is further configured, for each respective merged stream, to generate output data units by merging input data units assigned to that merged stream, such that each output data unit for that merged stream comprises the encoded data blocks of one input data unit from each of the respective input streams;
• and
• each input data unit consists of four 8-bit DP-16QAM words, whereby for each OFEC encoder of said OFEC encoder plurality, a same number of bits is allocated to each subcarrier of the subcarrier plurality, and a same number of bits is allocated to each of the two polarization channels.

Apparatus, comprising:

• a merging circuit configured to input at least an input stream A and an input stream B of sequentially ordered input data units of data encoded by a plurality of OFEC encoders, and to merge the said at least streams A and B so as to produce at least a first merged stream and a second merged stream of sequentially ordered output data units;
• and
• an allocating circuit configured to allocate one merged stream to an optical subcarrier SC0 of an optical communication system and to allocate another merged stream to an optical subcarrier SC1 of an optical communication system having two polarization channels, wherein:
• the optical subcarriers SC0 and SC1 belong to a plurality of at least two optical subcarriers;
• each of the input data units comprises one or more blocks of encoded data;
• the merging circuit is configured to assign input data units from the respective input streams to the respective merged streams by round robin distribution;
• the merging circuit is further configured, for each respective merged stream, to generate output data units by merging input data units assigned to that merged stream, such that each output data unit for that merged stream comprises the encoded data blocks of one input data unit from each of the respective input streams;
• and
• each input data unit consists of one 4-bit DP-QPSK word, whereby for each OFEC encoder of said OFEC encoder plurality, a same number of bits is allocated to each subcarrier of the subcarrier plurality, and a same number of bits is allocated to each of the two polarization channels.