symbol 3 and split on two frequency blocks at symbol 2 (Figure 4.8). To help the receiver to demodulate the PBCH signal, a DM-RS signal is associated with the PBCH. The DM-RS signal is transmitted on symbols 1, 2 and 3. In the frequency domain, CSI-RS is transmitted as a comb spaced by three subcarriers, as shown in Table 4.7. The comb helps to take frequency dispersion into account. The mobile UE performs power measurement on the SSB block (SS-RSRP- Synchronization Signal Reference Received Power) and estimates the quality of the SS-RSRQ (SS Reference Received Quality) radio link from the synchronization signal. The SS-RSRP measurement is averaged over the SS/PBCH Block Measurement Time Configuration (SMTC). The SS-RSRQ measurement is the ratio between the measured power SS-RSRP and the average power received by the mobile NR-RSSI (NR-Received Signal Strength Indicator). Here, V is the frequency shift (identity number of the modulo 4 cell). 5G-NR Radio Interface - The Physical Layer Number of Physical channel or signal Number of the subcarrier OFDM symbol 56,57,...,182 56,57,...,182 0,1,...,55, 183, 184, Zero-padding 48,49,..,55 183, 184, 0,1,.,239 0,1,...57 192,193,...239 0+v, 4+v,8+v,236+v DM-RS associated to PBCH 0+v, 4+v,...,44+v 192+v, 196+v,...,236+v Table 4.7. SSB mapping 48 sp 144 sp 12 RB 127 sp 48 sp Figure 4.8. SSB block 108 NG-RAN and 5G-NR 4.5.2. Reference signals 4.5.2.1. CSI-RS signal The physical CSI-RS (Channel State Information Reference Signal) signal allows the mobile to measure the received signal (CSI-RSRP) and measure the interference level of neighboring cells. The physical reference signal is either transmitted with a non-zero power to allow the receiver to determine the level of the received signal NZP-CSI-RS (Non Zero Power CSI-RS), or not transmitted ZP-CSI-RS to allow the receiver to measure the power level of neighboring base stations. The physical CSI-RS was introduced in Release R.10 to probe the propagation channel on the downlink. In 5G, the CSI-RS are specific to each UE. When 