A method for managing a cellular radio communications network is proposed. The method comprises: receiving (102) a plurality of numerology capability indications from a plurality of radio devices, wherein a numerology capability indication comprises one or more direct-link block lengths for communicating via a physical direct-link radio channel; receiving a plurality of cell indications, wherein the cell indication indicates in which radio cell the respective radio device is operating; determining an instruction message in dependence on the numerology indications of the first and second radio device and in dependence on the cell indication of the first and second radio device; and transmitting the instruction message towards at least one of the first and second radio devices.