Certain aspects of the present disclosure relate to communicating via grant-free uplink resources. An example method generally includes receiving, from a base station, a configuration indicating one or more sets of resources for grant-free uplink transmissions; determining a valid time to transmit a grant-free uplink transmission via the one or more sets of resources based on a transmission associated with the one or more sets of resources; and transmitting, to the base station, the grant-free uplink transmission based on the determination.