Synchronization Signal (SS): The time and frequency synchronization for random access. It consists of a primary synchronization signal and a secondary synchronization signal. Primary Synchronization Signal (PSS): Time and carrier synchronization detection. Secondary Synchronization Signal (SSS): Used for frame synchronization. Phase Tracking Reference Signal (PTRS): Compensates phase shifts. It is associated with PDSCH. General physical layer procedures Demodulation Reference Signal (DMRS) for PDCCH: Demodulation reference signals for PDCCH. Channel State Information Reference Signal (CSI-RS): Channel state measurements for beam forming, beam management, and Link Adaptation (LA). Demodulation Reference Signal (DMRS) for PDSCH: Demodulation reference signals for PDSCH. Tracking Reference Signal (TRS): In NR, there is no CRS to be used for fine time-frequency tracking. A device is configured with TRS, which is expressed as CSI-RS in the specification - that is, the device is configured with CSI-RS for tracking. Now, let's see the reference and synchronization signals in the uplink. Uplink reference and synchronization signals In the following figure, uplink reference and synchronization signals for NR are listed. Physical Channels PDSCH PDCCH PUSCH PUCCH PRACH Reference and Sync Signals CSI-RS/TRS PRACH Preamble Figure 4.7 - NR uplink reference and synchronization signals Physical Random Access Channel (PRACH) preamble: This is used for the initial transmission of a device. It is contention-based or contention-free. It is a timing and receiver beam estimation. Sounding Reference Signal (SRS): In reciprocity-based MIMO, this is used to estimate the UL channel and set the DL precoding. Demodulation Reference Signal (DMRS) for PUCCH: Demodulation reference signals for PUCCH. Demodulation Reference Signal (DMRS) for PUSCH: Demodulation reference signals for PUSCH. Phase Tracking Reference Signal (PTRS): This is associated with the Physical Uplink Shared Channel (PUSCH) to compensate for phase noise. We've analyzed refe