Processing circuitry for a wireless communication device, the processing circuitry to provide a wireless communication interface to transmit a signal or to receive a signal, the signal comprising a plurality of physical resource blocks generated depending on a resource block grid structure for a given channel bandwidth (104; 310) and a given frequency range, the resource block grid structure comprising: a reference alignment within the given channel bandwidth (104; 310) for a plurality of contiguous reference resource blocks corresponding to a reference subcarrier spacing; at least one further alignment within the given channel bandwidth (104; 310) for a plurality of contiguous respective further resource blocks of a respective further subcarrier spacing, the further alignment to align a boundary of a further resource block with a boundary of one of the reference resource blocks; wherein at least a subset of the resource blocks of the resource block grid structure are assigned as active resource blocks, the active resource blocks to define a transmission or reception bandwidth within the channel bandwidth and wherein the assignment of active resource blocks in the resource block grid structure is to preserve, at each end of the channel bandwidth (104; 310), at least a minimum guard band corresponding to the respective subcarrier spacing and the given channel bandwidth (104; 310) and the given frequency range; wherein at least one resource block of the reference alignment or the at least one further alignment not selected for the subset of active resource blocks is a virtual resource block (512a-c, 514a-e) used for resource block indexing to identify resource blocks of a respective subcarrier spacing for the given channel bandwidth and the given frequency range; wherein the at least one virtual resource block (512a-c, 514a-e) is not generally used for uplink or downlink communication at least by a user equipment; and wherein the virtual resource blocks (512a-c, 514a-e) are resource blocks closest to one or more band edges of the given channel bandwidth (104; 310). a reference alignment within the given channel bandwidth (104; 310) for a plurality of contiguous reference resource blocks corresponding to a reference subcarrier spacing; at least one further alignment within the given channel bandwidth (104; 310) for a plurality of contiguous respective further resource blocks of a respective further subcarrier spacing, the further alignment to align a boundary of a further resource block with a boundary of one of the reference resource blocks; wherein at least a subset of the resource blocks of the resource block grid structure are assigned as active resource blocks, the active resource blocks to define a transmission or reception bandwidth within the channel bandwidth and wherein the assignment of active resource blocks in the resource block grid structure is to preserve, at each end of the channel bandwidth (104; 310), at least a minimum guard band corresponding to the respective subcarrier spacing and the given channel bandwidth (104; 310) and the given frequency range; wherein at least one resource block of the reference alignment or the at least one further alignment not selected for the subset of active resource blocks is a virtual resource block (512a-c, 514a-e) used for resource block indexing to identify resource blocks of a respective subcarrier spacing for the given channel bandwidth and the given frequency range; wherein the at least one virtual resource block (512a-c, 514a-e) is not generally used for uplink or downlink communication at least by a user equipment; and wherein the virtual resource blocks (512a-c, 514a-e) are resource blocks closest to one or more band edges of the given channel bandwidth (104; 310).