Methods, systems, and devices for wireless communication are described. A base station may transmit a set of candidate resource element parameters to a wireless device. Each candidate resource element parameters may indicate a nominal number of physical resource block resource elements. The base station may then transmit downlink control information and a data transmission during a slot. The data transmission may include one or more transport blocks whose size is based on a nominal number of physical resource block resource elements. The wireless device may select one of the candidate resource element parameters from the set of candidate resource element parameters based at least in part on the downlink data, determine a transport block size for the data transmission, and decode the data transmission.