The invention relates to a method for evaluating the usability of a sub-carrier of a BPL (broadband power-line) signal, in particular in order to avoid mutual influencing of the BPL signal and a further signal, wherein the BPL signal has a plurality of sub-carriers and one symbol can be transmitted in each of the sub-carriers. The method comprises the following steps: extracting a received value y[k] from a sub-carrier of a received BPL signal, rectifying the received value y[k] using an estimated transfer function Ĥ of the transmission channel, deciding on a symbol d[k] that is coded in the received value y[k], distorting the symbol d[k] using the estimated transfer function Ĥ of the transmission channel, calculating a difference between the received value y[k] and the processed signal d[k]·Ĥ and deciding on the usability of the sub-carrier on the basis of the difference y[k]−d[k]·Ĥ.