A position of a device within a cluster of multiple devices is determined and stored in a memory. An uplink radio resource is mapped from a downlink radio resource in dependence on the determined position of the device within the cluster of multiple devices. In an embodiment the respective uplink and downlink radio resource is a PUCCH and PDCCH of a cellular network, and the cluster is a D2D network. In one embodiment the device position is an index j which is used to offset from a predetermined mapping pattern. In another embodiment the position of the device corresponds to an individual field of a transmission on the PDCCH and the mapping is in dependence on a bit value in the individual field.