| CPC H04W 76/19 (2018.02) [H04B 7/088 (2013.01); H04L 5/0051 (2013.01); H04W 74/0833 (2013.01); H04W 74/0838 (2024.01)] | 17 Claims |

|
1. An apparatus, comprising:
at least one processor; and
at least one non-transitory memory storing instructions that, when executed with the at least one processor, cause the apparatus to perform:
receiving reference signals comprising at least one of a plurality of channel synchronization signal blocks or state information reference signals on a downlink channel;
measuring at least one of received signal power or quality level of said reference signals;
estimating arrival directions or an arrival antenna panel for a plurality of beams associated with said reference signals;
estimating, based on at least one of the received signal power or quality level, a required transmission power for a random access channel preamble for the plurality of beams;
selecting, in response to detecting a failure of a serving beam, another of said plurality of beams according to at least one of spatial diversity or required transmission power; and
sending the random access channel preamble on the selected beam; and
ranking at least one beam of the plurality of beams into a preference order based on at least the arrival direction or the arrival antenna panel of the ranked beams and the required transmission power for the random access channel preamble of the ranked beams.
|