1. DM-RS (Demodulation Reference Signals) are transmitted in the frequency domain, they are used to demodulate the downlink data and control channels, and they can be used for cell measurement such as cell identification, cell reselection, and handover. B. CSI-RS (Channel State Information Reference Signals) are also transmitted in the frequency domain, they are used to provide channel state information for downlink data and control channels, and they can be used for cell measurement such as link adaptation, beamforming and interference management.

DM-RS stands for Demodulation Reference Signal and is used for channel estimation in the frequency domain. CSI-RS stands for Channel State Information Reference Signal and is used for channel estimation in the time-frequency domain. PT-RS and SSB are not channels (signals) that can be used for cell measurement in NR.