e mobile for the implementation of the OTDOA (Observed Time Difference Of Arrival) function. The OTDOA function is based on the measurement by the mobile of the difference in the reception time of the physical PRS signal compared to a reference cell. The location of the mobile is obtained from three measurements taken on three geographically dispersed cells. 6.2.2. Uplink transmission Table 6.3 shows the association of antenna ports and uplink channels and physical signals. Antenna port Reference signal P0-P7 DM-RS (PUSCH) P1000 P2000 DM-RS (PUCCH) P4000 PRACH Table 6.3. Numbering of the antenna port in uplink transmission 6.2.2.1. The SRS physical signal The SRS (Sounding Reference Signal) physical signal is used to perform coherent demodulation of the received signal. The coherent demodulation of the received signal is based on the estimation of the transfer function of the radio channel. The SRS physical signal allows the implementation of spatial multiplexing and transmission diversity. 5G-NR Radio Interface - MIMO and Beamforming 6.2.2.2. The DM-RS physical signal in uplink The DM-RS physical signal is used for the beamforming mechanism and for spatial multiplexing of several users. The DM-RS allows the demodulation of the physical channel with which it is associated, either the PUCCH (Physical Uplink Control Channel) or the PUSCH (Physical Uplink Shared Channel). The DM-RS physical signal on the uplink allows a user to exploit up to four spatial layers. 6.2.2.3. The PRACH physical signal The PRACH (Physical Random Access Channel) signal carries the random access preamble. 6.3. Uplink Control Information (UCI) UCI represents the data transmitted by the mobile which contains the scheduling requests (SR), the HI hybrid acknowledgment (HARQ Indicator) and the CSI report. The HI information concerns the positive ACK or negative NACK acknowledgment of data received on the PDSCH physical channel. The CSI, determined by the UE, groups together information relating to the status reports of the signal received on the