For each numerology and carrier, a resource grid of Ngrid,xsize,μNscRB subcarriers and Nsymbsubframe,μ OFDM symbols may be defined, starting at common resource block Ngridstart,μ indicated by higher-layer signalling. There may be one set of resource grids per transmission direction (uplink or downlink) with the subscript x set to DL and UL for downlink and uplink, respectively. When there is no risk for confusion, the subscript x may be dropped. There may be one resource grid for a given antenna port p, subcarrier spacing configuration μ, and transmission direction (downlink or uplink).
The carrier bandwidth Ngridsize,μ for subcarrier spacing configuration μ may be given by the higher-layer parameter carrierBandwidth in the SCS-SpecificCarrier IE. The starting position Ngridstart,μ for subcarrier spacing configuration μ may be given by the higher-layer parameter offsetToCarrier in the SCS-SpecificCarrier IE.
The frequency location of a subcarrier refers to the center frequency of that subcarrier. For the downlink, the higher-layer parameter DirectCurrentLocation in the SCS-SpecificCarrier IE may indicate the location of the transmitter DC subcarrier in the downlink for each of the numerologies configured in the downlink. Values in the range 0-3299 represent the number of the DC subcarrier and the value 3300 indicates that the DC subcarrier is located outside the resource grid.