5G NR cell SSB demodulation method, terminal, base station and system

The invention provides a 5G NR cell SSB demodulation method, a terminal, a base station and a system, and belongs to the technical field of SSB demodulation, the method comprises the following steps: in an initial beam establishment stage, a base station side periodically sends SSB; for a plurality of SSBs in the same period, the terminal adopts the same receiving beam; for SSBs in different periods, the terminal adopts different receiving beams; selecting the receiving beam with the strongest received RSRP from the SSBs received by all the receiving beams as a downlink receiving beam; the base station issues CSI-RS to the terminal, and the terminal uses different downlink receiving beams on different OFDM symbols, selects the strongest RSRP and reports the strongest RSRP to the base station; selecting a receiving beam corresponding to the strongest RSRP to update a downlink sending beam; and selecting a receiving beam with the strongest RSRP from measurement results on different OFDM symbols as a downlink re