ysical Layer Aspects (Part 2) 649 mechanism where the preamble may be retransmitted with a transmit power that is increased in steps during each transmission attempt. The device selects the initial PRACH preamble transmit power based on estimates of the downlink path loss in combination with a target received preamble power configured by the network. The path loss should be esti- mated based on the received power of the SS/PBCH block that the device has acquired and has determined the RACH resources for preamble transmission. If no random-access response is received within a predetermined window, the device can assume that the pream- ble was not correctly received by the network. In that case, the device repeats the preamble transmission with an increased transmit power. This power ramping continues until a random-access response has been received or until a configurable maximum number of retransmissions are attempted. Under such condition the random-access transmission has failed [14]. When uplink beamforming is used, the uplink path loss estimate PLklm(qd) is used to deter- mine the transmit power. The latter path loss estimate includes the effect of beamforming gain of the uplink beam pair to be used for PUSCH transmission. Assuming beam corre- spondence, this can be achieved by estimating the path loss based on measurements on a downlink reference signal transmitted over the corresponding downlink beam pair. As the uplink beam used for the transmission pair may change between PUSCH transmissions, the device may have to perform multiple path loss estimates corresponding to different candi- date beam pairs. During PUSCH transmission over a specific beam pair, the path loss esti- mate corresponding to that beam pair is used to determine PUSCH transmit power. This is enabled by the parameter q in the path loss estimate PLkim(qd)[14]. The gNB configures the UE with a set of downlink reference signals based on which the path loss is estimated. Each reference signal is associated with a specific value of q. To limit