2.1.1 SRS resource indicator or SRS resource identity (ID) or SRS resource index (SRI), SSB resource indicator or SSB resource identity (ID) or SSB resource index (SSBRI) or CSI-RS resource indicator or CSI-RS resource identity (ID) or CSI-RS index (CRI) indication:

For example, if a CSI-RS is used for DL BM and an SRS is used for UL BM, if a DL-based UL beam association has been activated, a base station may share information about which BPL will be used with a terminal by notifying the terminal of a CRI. In this case, a method of providing notification of a given BPL by combining a CRI and a CSI-RS port in addition to using only the CRI may be used. In contrast, if a DL→UL beam association has not been activated, a base station may share information about which BPL will be used with a terminal by notifying the terminal of an SRS resource indicator (SRI). For another example, a base station may share information about which BPL will be used with a terminal by an SRI. In this case, a method of providing notification of a given BPL by combining an SRI and an SRS port in addition to using only the SRI may be used. For yet another example, a base station may share information about which BPL will be used with a terminal by transmitting an SSBRI. In this case, a method of providing notification of a given BPL by combining an SSBRI and an SSBRI port in addition to the use of only the SSBRI may be used. If different RSs are used for DL BM and UL BM, BPL information may be notified using an RS resource and an RS port using the same method.