Beam failure recovery method of base station in wireless communication system using ris, apparatus therefor, and program therefor

A beam failure recovery method of a base station (BS) in a wireless communication system using a reconfigurable intelligent surface (RIS), the beam failure recovery method comprising:

• configuring a candidate beam set, based on a measured reference signal received power (RSRP) value in beam sweeping using an antenna;
• establishing a communication link with a user equipment (UE) through a main beam having the measured RSRP value exceeding a predetermined threshold in the configured candidate beam set;
• selecting a beam, based on the measured RSRP value, from a synchronization signal block (SSB) to which the main beam belongs and an SSB to which the main beam does not belong when beam failure occurs in the established communication link;
• and
• recovering the beam failure with the UE through the selected beam,
• wherein the configuring of the candidate beam set comprises comprising a plurality of beams included in a direct path to the UE and a reflective path through the RIS in the candidate beam set, and
• wherein the beam failure recovery method further comprises, before the selecting of the beam,
• obtaining measured values of an angle of arrival (AoA), an angle of departure (AoD), and a time of arrival (ToA) corresponding to each beam of the candidate beam set;
• and
• corresponding each beam to the direct path or the reflective path, based on the obtained measured values.