Method and apparatus for transmitting data in a super channel

A transmitter for transmitting digital data in a super channel, in which a set of carriers are packed in a predetermined band width, said set of carriers comprising higher and lower edge carriers having the highest and lowest wavelengths, respectively, among said set of carriers, wherein said transmitter is configured to transmit data via the higher and lower edge carriers using a corresponding modulation format, each modulation format using a constellation diagram comprising a number of symbols, wherein a binary address is associated with each symbol, wherein said transmitter is configured for carrying out the steps of:

• separating digital data to be transmitted via each of said higher and lower edge carriers into corresponding first and second data streams,
• for each of said higher and lower edge carriers, mapping the data of the first data stream to predetermined first bit positions within the binary symbol addresses and the data of the second data stream to predetermined second bit positions within the binary symbol addresses, wherein said first bit positions are bit positions which have an error probability less than the average error probability of all bit positions.

A receiver for receiving digital data in a super channel, in which a set of carriers are packed in a predetermined band width,

• said set of carriers comprising higher and lower edge carriers having the highest and lowest wavelengths, respectively, among said set of carriers, wherein data is transmitted via the higher and lower edge carriers using a corresponding modulation format, each modulation format using a constellation diagram comprising a number of symbols, wherein a binary address is associated with each symbol, and wherein digital data transmitted via each of said higher and lower edge carriers comprises first and second data streams, said receiver being configured to carry out the steps of
• for each of said higher and lower edge carriers, demapping data of a said first data stream from predetermined first bit positions within the binary symbol addresses and data of said second data stream from predetermined second bit positions within the binary symbol addresses, wherein said first bit positions are bit positions which have an error probability less than the average error probability of all bit positions.