ce block in the resource and the number of frequency-domain PRACH occasions [14]. In NR, the set of random-access preambles xu,v(n) is generated based on Zadoff-Chu sequences such that xu,v(n) = =xx[(n+C,)mod LRA] wherein Xu(i) = exp( - jui(i + 1)/LRA) is a Zadoff-Chu sequence of length LRA and root index ; and i = 0, 1, LRA - The frequency-domain representation of the preamble sequence is obtained by taking LRA - point DFT of the sequence Xu,v(n), resulting in = exp( - j2mn/LRA) where the sequence length LRA = 839 or LRA = 139 depend on the PRACH preamble format (see Tables 4.27 and 4.28). There are 64 preambles in each time-- frequency PRACH occasion, numbered in increasing order of cyclic shift Cv of a logical root sequence and increasing order of the logical root sequence index, starting with the index obtained via RRC signaling. The sequence number is obtained from the logical root sequence index [6]. The output of the DFT is then repeated NSEQ times, after which a cyclic prefix is inserted. For the PRACH preamble, the cyclic prefix is not inserted per OFDM symbol, rather it is inserted only once for the block of NSEQ repeated symbols (see Fig. 4.83). New Radio Access Physical Layer Aspects (Part 2) 621 Format 0 Preamble sequence fra 1.25 kHz NSEQ = 1 NRA A Format 1 Preamble sequence Preamble sequence fra 1.25 kHz NSEQ = 2 Format 3 fra = 5 kHz NSEQ = 4 NRA H General structure Preamble Preamble Preamble of short PRACH sequence 0 sequence 1 sequence NSEQ-1 preambles NRA H repetition of the preamble sequence) Figure 4.83 NR PRACH preamble structures [6]. The time-domain representation of PRACH signal SPRACH(t,I) on a single-antenna port is given as follows [6]: Chapter 4 Table 4.30: Supported combinations of Afra and Af, and k [6]. Afra for PRACH for PUSCH NRA E (RBs) for PUSCH In the preceding expression k is given in Table 4.30 [6]. Af is the subcarrier spacing of the active uplink bandwidth part during the initial access; otherwise, If is the subcarrier spacing of the active uplink bandwidth part (see Table 