 scaling factor BPUCCH,S to properly adjust the transmit power and are subse- quently mapped starting with z(0) to resource elements (k, 1) which are designated to PUCCH transmission and are not used by the associated PUCCH DM-RS. The mapping to New Radio Access Physical Layer Aspects (Part 2) 617 resource elements is done in frequency-first manner on a single-antenna port. In case of intra-slot frequency hopping, OFDM symbols are transmitted in the first hop and the in the second hop where NPUCCH,S symb the total number of OFDM symbols used in one slot for PUCCH transmission [6]. The physical processing and structure of PUCCH formats 3 and 4 are illustrated in Fig. 4.81. 4.2.3.2 Physical Random-Access Channel The NR supports a four-step random-access procedure similar to LTE. However, beam- forming and beam tracking aspects introduced in NR random-access procedure make the overall process different from that of LTE in frequencies above 6 GHz. The UEs need to detect and select the best beam for RACH process (beam selection process) prior to PRACH sequence selection and transmission. The PRACH design in NR relies on Zadoff-Chu sequences for the preamble construction. There are three PRACH preamble formats with long sequence length of 839, two of which, with subcarrier spacing of 1.25 kHz (same as LTE), are used for LTE refarming and large cells (up to 100 km); another format with subcarrier spacing of 5 kHz is defined for high-speed scenarios (up to 500 km/h) and cell radius up to 14 km (see Tables 4.27 and 4.28). Long sequences support Table 4.27: PRACH preamble formats for LRA = 839 and Afra E {1.25,5} kHz [6]. PRACH Subcarrier Spacing Bandwidth Support for Format Afra (kHz) (MHz) Restricted Sets 24576Ts 3168Ts 2976Ts Type A, Type B 24576Ts 21024Ts 21984Ts 24576Ts 4688Ts 29264Ts 24576T 3168Ts 2976Ts Table 4.28: Preamble formats for LRA = 139 and Afra = 2H X 15 kHz where HE {0, 1,2,3} and K = 64 [6]. PRACH Format LRA Samples Afra (kHz) NRA Samples NRA Samples 2 th X 15 2048Ts 2 X 2048k2 -" 288k2-H 4 X 2048k2 - 57