Certain aspects of the present disclosure provide techniques for slot aggregation in new radio (NR) systems. A method of wireless communication by a user equipment (UE) includes receiving radio resource control (RRC) signaling providing a semi-static configuration for transmission and/or reception of a repeated transport block (TB) and/or a different TB in each of a plurality of aggregated slots. The UE transmits or receives the TBs in the plurality of aggregated slots based on the semi-static configuration. Another method is provided in which the UE transmits and/or receives a demodulation reference signal (DMRS) in each of a plurality of aggregated slots, each DMRS associated with a repeated TB or a different TB in the slot. The UE determines, based on received signaling, whether the DMRS use a same precoder or a different precoder and modulates and/or demodulates the TBs in the plurality of aggregated slots based on the determination.