Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit, to a base station, channel state information (CSI) feedback indicating a modulation and coding scheme (MCS) associated with a spectral efficiency below a minimum MCS index in a spectral efficiency table. The UE may receive, from the base station, a downlink transmission including a number of resource blocks (RBs), wherein the number of RBs is based at least in part on the spectral efficiency associated with the MCS indicated in the CSI feedback. Numerous other aspects are described.