Patent ID: 7864737

Claim:
A method for transmitting data via a subscriber transmission link, comprising: predetermining a reference sequence and a reference method for transmitting the reference sequence, wherein a main frequency range is provided for transmitting the reference sequence; predetermining in the main frequency range at least one underfrequency range which is not to be used during a transmission of useful data via a transmission link; in a transmitter generating a test signal having a power spectral density based on the reference sequence and the reference method; reducing the power spectral density of a component of the test signal in the underfrequency range, in deviation from the reference sequence or in deviation from the reference method; transmitting the test signal via the transmission link from the transmitter to a receiver; in the receiver characterizing the transmission link by using the received test signal and by assuming, that the test signal has been generated from the reference sequence and by using the reference method; allocating to the underfrequency range a number of bits which can be transmitted in the underfrequency range depending on the characterization of the transmission link in the underfrequency range; transmitting from the receiver to the transmitter a value specifying the allocated number of bits; iteratively reducing the power spectral density until the value transmitted by the receiver is zero.