An optical transceiver comprising: a transmitter configured to transmit a first signal including a first sequence comprising n symbols to a receiver of a further optical transceiver, n being a positive integer, and a receiver coupled to the transmitter and configured to: receive a first compensation from a transmitter of the further optical transceiver, wherein the first compensation is based on a pattern-dependent analysis of the first signal; and provide the first compensation to the transmitter, wherein the transmitter is further configured to: compensate a second signal based on the first compensation to form a first compensated signal, and transmit the first compensated signal to the receiver of the further optical transceiver, wherein the first compensation is a first pattern-dependent look-up table, PD-LUT, wherein the first PD-LUT comprises a first pattern index and a first adjustment corresponding to the first pattern index, wherein the first pattern index is calculated by multiplying the first symbol in the first sequence of the first signal by a number of matched levels raised to the power of the symbol number, multiplying the second symbol in the first sequence of the signal by the number of matched levels raised to the power of the symbol number, and further for each of the n symbols of the first sequence, then adding the quantities together. a transmitter configured to transmit a first signal including a first sequence comprising n symbols to a receiver of a further optical transceiver, n being a positive integer, and a receiver coupled to the transmitter and configured to: receive a first compensation from a transmitter of the further optical transceiver, wherein the first compensation is based on a pattern-dependent analysis of the first signal; and provide the first compensation to the transmitter, receive a first compensation from a transmitter of the further optical transceiver, wherein the first compensation is based on a pattern-dependent analysis of the first signal; and provide the first compensation to the transmitter, wherein the transmitter is further configured to: compensate a second signal based on the first compensation to form a first compensated signal, and transmit the first compensated signal to the receiver of the further optical transceiver, wherein the first compensation is a first pattern-dependent look-up table, PD-LUT, wherein the first PD-LUT comprises a first pattern index and a first adjustment corresponding to the first pattern index, wherein the first pattern index is calculated by multiplying the first symbol in the first sequence of the first signal by a number of matched levels raised to the power of the symbol number, multiplying the second symbol in the first sequence of the signal by the number of matched levels raised to the power of the symbol number, and further for each of the n symbols of the first sequence, then adding the quantities together. compensate a second signal based on the first compensation to form a first compensated signal, and transmit the first compensated signal to the receiver of the further optical transceiver, wherein the first compensation is a first pattern-dependent look-up table, PD-LUT, wherein the first PD-LUT comprises a first pattern index and a first adjustment corresponding to the first pattern index, wherein the first pattern index is calculated by multiplying the first symbol in the first sequence of the first signal by a number of matched levels raised to the power of the symbol number, multiplying the second symbol in the first sequence of the signal by the number of matched levels raised to the power of the symbol number, and further for each of the n symbols of the first sequence, then adding the quantities together.