Abstract: A receiver (1) is configured to receive an optical transmission, wherein the receiver is configured to determine a plurality of values over time of the quality of the optical transmission. The receiver comprises one or more low pass filter (26) configured to low pass filter the values of quality of the transmission. Based on the low pass filtered values, the receiver (1) is configured to determine a FEC code and/or modulation type for a further optical transmission.

Abstract: An optical multi carrier signal has a modulation format and has many individual carrier signals. Parameters of the signal are controlled by receiving an indication of individual carrier transmission performance of the individual carrier signals, and selecting parameter values for the individual carrier signals, the parameter values comprising both a carrier FEC overhead and a carrier bandwidth for the modulation format. Selection is made according to the indicated individual carrier transmission performance and according to an overall spectral efficiency of the multi carrier signal. The selected parameter values are output for control of the optical multi carrier signal. By selecting values for both parameters rather than either one, better optimization can be obtained since they are interdependent. The control can have better granularity than changing modulation format, and can make better use of bandwidth or improve the overall capacity.

Abstract: A receiver (1) is configured to receive an optical transmission, wherein the receiver is configured to determine a plurality of values over time of the quality of the optical transmission. The receiver comprises one or more low pass filter (26) configured to low pass filter the values of quality of the transmission. Based on the low pass filtered values, the receiver (1) is configured to determine a FEC code and/or modulation type for a further optical transmission.

Abstract: An optical multi carrier signal has a modulation format and has many individual carrier signals. Parameters of the signal are controlled by receiving an indication of individual carrier transmission performance of the individual carrier signals, and selecting parameter values for the individual carrier signals, the parameter values comprising both a carrier FEC overhead and a carrier bandwidth for the modulation format. Selection is made according to the indicated individual carrier transmission performance and according to an overall spectral efficiency of the multi carrier signal. The selected parameter values are output for control of the optical multi carrier signal. By selecting values for both parameters rather than either one, better optimisation can be obtained since they are interdependent. The control can have better granularity than changing modulation format, and can make better use of bandwidth or improve the overall capacity.