2.3 DL BPL indication through beam index indication: a method of sharing a BPL to be use for DL transmission by providing notification of a beam index used in beam sweep during a BM process. It is assumed that in an UL BM process, a terminal performs beam sweep using 16 beams and a base station forms BPLs by notifying the terminal of the indices of the four preferred beams of the 16 beams. In this case, since the four BPLs are formed, there is a difference in that for DL BPL indication, an activated BPL of the four candidates is notified in Method 2.2 and an activated BPL of the 16 candidates is notified in Method 2.3.

FIG. 6 is a diagram showing a process of applying a beam used for DL transmission through indication if an UL-based DL beam association has been activated according to a third embodiment of the disclosure.

Referring to FIG. 6, operation 610 shows an example in which two BPLs have been established through SRS-based UL BM. In this case, it is assumed that an SRS #1-based BPL 611 has been determined to be used for UL transmission and an SRS #2-based BPL 613 has been determined to be used for DL transmission. Next, operation 620 is a process for a base station to perform indication necessary for an UL-based DL beam association to a terminal. The corresponding indication includes the aforementioned indication regarding whether an UL-based DL beam association has been activated and the DL BPL indication, and is transmitted using a BPL of a previous version selected for DL transmission in operation 630. In FIG. 6, a right operation indicates a process for the terminal to update a DL BPL based on received indication and to perform DL reception. In this case, the DL BPL may be applied to a DL CSI-RS, a DL DMRS, a PDCCH or a PDSCH.