 the same beam that was used for the random-access preamble transmission, implying that the network can assume that the uplink receive beam established at the initial access will remain valid. In LTE, a UE continuously performs radio link monitoring of the channel quality of its serving cell to ensure sufficient coverage of control channels. If the link quality is consid- ered poor, the UE declares RLF and triggers a higher layer connection reestablishment pro- cedure, resulting in cell reselection. For a large number of antennas, the UE-specific beams are narrow, and beam tracking can fail, for example, when a moving object blocks the LoS path to the UE. This event is regarded as beam failure in NR. In this case declaring RLF and performing cell reselection is unnecessary since another beam from the same cell can be used to cover the UE. This physical layer procedure is an example of beam recovery, in which the UE continuously monitors a UE-specific periodic reference signal associated with the TX beam with which a control channel is transmitted. If the measured beam quality deteriorates, the UE declares beam failure and proceeds to identify an alternative candidate TX beam, selected from a set of UE-common TX beams used for the periodic beam sweep- ing of initial access signals. These beams are typically wider compared to UE-specific data beams. As a part of this TX beam determination, the UE also determines an appropriate RX beam to receive the indicated TX beam. When a new beam is detected, the UE transmits a beam recovery request message using a preconfigured uplink resource (which includes an identifier of the new beam) to the serving cell. The network then transmits a recovery response to the UE. If the response is successfully received by the UE, the beam recovery procedure is successful, and a new beam pair is established; otherwise, the UE may perform additional beam recovery attempts, which upon failure would force the UE to initiate the RLF procedure, which includes cell reselection [57]. New Radio Ac