Patent ID: 8401383

Claim:
A data transmission method for transmitting a digital optical signal over an optical transmission link, the data transmission method comprising: a. creating a digital optical channel signal defining at least a first and a second service level, an aggregate information comprising information transported in the first service level and of information transported in the second service level being included in the digital optical channel signal via a modulation scheme comprising at least three modulation symbols, all of the modulation symbols differing in at least one modulation parameter, b. transmitting said digital optical channel signal at a near end over the transmission link, c. receiving said transmitted digital optical channel signal at a remote end of the transmission link by demodulating said received signal and extracting the information of the first and second service levels into a received signal, d. wherein, under normal operating conditions of the transmission link, one or more of the modulation parameters of the modulation scheme, receiving parameters of the transmission link, or transmission parameters of the transmission link are controlled such that the transmission performance with respect to the information transported in said first and second service level or the transmission performance with respect to the aggregate information transported in the digital optical channel signal reach predetermined quality levels, e. determining the transmission performance with respect to the information transported in said first and second service level or the transmission performance with respect to the aggregate information transported in the digital optical channel signal, and f. wherein in case that the relevant transmission performance is below a given threshold due to increased constraints of the transmission link at least one of the following actions is taken: i. The information transported in at least one service level is dropped from being included in the digital optical channel signal, the modulation scheme being designed such that dropping the at least one service level results in a reduction of the number of modulation symbols used for the digital optical channel signal transporting the information of the remaining service level or levels; or ii. one or more of the modulation parameters of the modulation scheme, receiving parameters of the transmission link, or transmission parameters of the transmission link are dynamically determined such that the transmission performance with respect to the information transported in one of said first and second service levels is increased to a predetermined quality level while decreasing the transmission performance of the respective other service level or levels.