rence and synchronization signals. Now, let's see how some of those are related to the NR cell definition. 5G Air Interface and Physical Layer Procedures - Part 1 NR cell definition A Synchronization Signal block (SSB - SS block) information defines an NR cell. The SS block is composed of PSS, SSS, and a Physical Broadcast Channel (PBCH). We will analyze the SS block in greater detail in the next chapter within initial access procedures. A cell ID is created by PSS and SSS. The PBCH carries a Master Information Block (MIB). The MIB provides important parameters to devices to acquire the System Information Block 1 (SIB1), which contains the configuration for system access. SI area "SS Block" transmissions defines the NR Cell Figure 4.8 - NR cell definition A SIB2 or higher can be specific to a cell or System Information (SI) area. There can be several cells in an SI area. The details of SIB1, SIB2, and the remaining SIB messages are listed here: SIB 1: Cell selection/barring, radio resource configuration, and scheduling of other SIBs SIB 2: Cell reselection (intra-frequency, inter-frequency, and Inter Radio Access Technology (IRAT)) in common SIB 3: Intra-frequency cell reselection-specific information SIB 4: Inter-frequency cell reselection-specific information SIB 5: IRAT cell reselection-specific information SIB 6 and SIB 7: Earthquake and Tsunami Warning System (ETWS) SIB 8: Commercial Mobile Alert Service (CMAS) SIB 9: GPS time and Coordinated Universal Time (UTC) We will now see how the reference signals are used for cell measurement. General physical layer procedures NR cell measurement signals NR has a lean design, and there are less frequent reference signals compared to LTE. There is no Cell Specific Reference Signal (CRS) in NR. PSS, SSS, and CSI-RS are used instead. A device uses CSI-RS to measure the channel and report the Channel Quality Information (CQI) to the gNB to aid beamforming, beam management, and link adaptation. The SIB content is minimalistic in NR; if the device needs more, it is sent by