A method performed by a first network node of a cellular system for communication between the first network node and a second network node over a communication channel comprising a twisted pair wire, the method comprising: receiving, over the communication channel comprising the twisted pair wire, an intermediate frequency signal from the second network node, which intermediate frequency signal has been converted by the second network node from a high frequency signal having a frequency higher than the frequency of the intermediate frequency signal, and converting the intermediate frequency signal to a low frequency signal having a frequency lower than the frequency of the intermediate frequency signal, wherein the first network node is arranged to receive intermediate frequency signals from a plurality of second network nodes over separate communication channels comprising twisted pair wires, each of the communication channels connecting one of the plurality of second network nodes with the first network node, characterized in the method further comprising: estimating (512; 612) transmission quality for the communication channels; allocating (514; 614) intermediate frequencies to the communication channels based on the estimated transmission qualities such that a first of the communication channels having a first estimated transmission quality is allocated a lower intermediate frequency than a second of the communication channels having a second estimated transmission quality higher than the first estimated transmission quality. receiving, over the communication channel comprising the twisted pair wire, an intermediate frequency signal from the second network node, which intermediate frequency signal has been converted by the second network node from a high frequency signal having a frequency higher than the frequency of the intermediate frequency signal, and converting the intermediate frequency signal to a low frequency signal having a frequency lower than the frequency of the intermediate frequency signal, wherein the first network node is arranged to receive intermediate frequency signals from a plurality of second network nodes over separate communication channels comprising twisted pair wires, each of the communication channels connecting one of the plurality of second network nodes with the first network node, characterized in the method further comprising: estimating (512; 612) transmission quality for the communication channels; allocating (514; 614) intermediate frequencies to the communication channels based on the estimated transmission qualities such that a first of the communication channels having a first estimated transmission quality is allocated a lower intermediate frequency than a second of the communication channels having a second estimated transmission quality higher than the first estimated transmission quality. estimating (512; 612) transmission quality for the communication channels; allocating (514; 614) intermediate frequencies to the communication channels based on the estimated transmission qualities such that a first of the communication channels having a first estimated transmission quality is allocated a lower intermediate frequency than a second of the communication channels having a second estimated transmission quality higher than the first estimated transmission quality.