ed by the base station; 2) the mobile transmits precoded SRSs to assist the base station in estimating the upstream channel per beam; 3) the code selection done by the mobile aims to select the best code from a mobile point of view. However, this code may cause interference with other users. The base station can modify the choice of code from the mobile measurement report of the SRS-multi-port signals. The code change is then transmitted in the DCI 0 descending control information message and in the UL Grant resource allocation request. 6.6. Beamforming management 6.6.1. Burst SSB: beam sweeping The SSB block requires an allocation of 240 sub-carriers in the frequency domain and four symbols in the time domain. NG-RAN and 5G-NR In the FR1 band, the spacing between sub-carriers of the SSB block is 15 kHz or 30 kHz. In the FR2 band, the sub-carrier spacing of the SSB block is 120 kHz 240 kHz. Numerology SSB bandwidth Block duration 3.6 MHz 286 us 7.2 MHz 143 us 28.8 MHz 36 us 57.6 MHz 18 us Table 6.6. SSB characteristics The SSB is periodically broadcasts by the base station. The periodicity varies between 5 ms and 160 ms. However, the mobile assumes that the periodicity of the SSB is 20 ms. An SSB burst is made up of several SSBs over a half sub-frame (5 ms): - 1-4 SSB for a carrier frequency lower than 3 GHz; 1-8 SSB for a carrier frequency between 3 GHz and 6 GHz; - 1-64 SSB in the FR2 band. Beam sweeping of the synchronization signal is realized by SSB burst broadcasting. Frame 10 ms Frame 10 ms Frame 10 ms Frame 10 ms Half-frame 5 ms Slot 1 ms Slot 1 ms Slot ms Slot 1 ms Slot 1 ms The first block is located at symbols 2 to 5. The second block is located at symbols 8 to 11. The third block is located at symbols 16 to 19. The fourth block is located at symbols 22 to 25. Figure 6.15. SSB block on the temporal domain 5G-NR Radio Interface - MIMO and Beamforming The periodicity of the SSB block and the number of SSB blocks per burst are defined in the data structure ServingCellConfigCommonSIB. The ServingCellConfig