If the DL-based UL beam association has been activated, the terminal may receive DL BM-based UL BPL indication from the base station at operation 385. For example, the terminal may receive information on the resource indicator of a DL beam to be used for UL transmission from the base station. For a detailed method of transmitting the UL BPL indication, reference is made to the operation of the first embodiment. Operation 365 and operation 385 are different in the contents of the indications. The indications of operations 365 and 385 may be included in a single message and transmitted or may be included in different messages and transmitted.

After operation 380 or operation 385, the terminal may transmit an UL signal, data or an RS to the base station based on the indicated UL BPL at operation 390.

The second embodiment is an embodiment in which a BPL established through DL BM is applied to UL transmission and a BPL established through UL BM may also be applied to DL transmission. Assuming that a CSI-RS and an SRS are respectively used for DL BM and UL BM, a beam applied to DL transmission may include the following cases depending on whether a DL-UL reciprocal beam is associated in the second embodiment.

• • With DL-UL reciprocal beam association: an SRS-based DL CSI-RS/DL DMRS/PDCCH/PDSCH is possible.
  • Without DL-UL reciprocal beam association: a CSI-RS-based DL DMRS/PDCCH/PDSCH is possible.

Likewise, a beam applied to UL transmission may include the following cases.