According to some embodiments, a method for use in a network node of transmitting channel state information reference signals (CSI-RS) comprises: transmitting, to the wireless device, an indication of the subset of PRBs that the wireless device should use to measure CSI-RS; and transmitting CSI-RS on the indicated subset of PRBs. According to some embodiments, a method for use in a wireless device of receiving CSI-RS comprises: receiving an indication of a subset of PRBs that the wireless device should use to measure CSI-RS associated with an antenna port; and receiving CSI-RS on the indicated subset of PRBs. In some embodiments, the indication of the subset of PRBs that the wireless device should use to measure CSI-RS comprises a density value and a comb offset.