Patent ID: 8594514

Claim:
A method comprising: receiving, with a node, a phase-modulated signal that carries client symbols and a control sequence, the node having a memory associated therewith, where the control sequence includes: first control symbols on which a first tone is to be based, the first tone having a first power level, and second control symbols on which a second tone is to be based, the second tone having a second power level; processing a first portion of the signal to generate the first tone and a second portion of the signal to generate the second tone, where the first portion includes the first control symbols and where the second portion includes the second control symbols; determining a power difference based on a difference between the first power level and the second power level; retrieving, from the memory, condition information, associated with the control sequence, that identifies a threshold for determining whether a condition, that corresponds to a particular type of condition, is associated with the signal based on the power difference; determining whether the power difference is greater than the threshold; determining that the condition is associated with the signal when the power difference is greater than the threshold; and outputting an instruction to adjust a parameter, used to transmit the signal, based on the determination that the condition is associated with the signal, where the instruction to adjust the parameter causes the power difference to decrease to a level that is less than the threshold.