ble 3.5.3 Supported PRACH preambles. PRACH formats Long sequence, 839 samples Short sequence, 139 samples Format SCS, kHz Duration, ms Use case Format SCS, kHz Duration, ms Use case 2n 15 0.0094 Small cell Large cell, 2H 15 0.0188 Normal cell >100 km Coverage 2H 15 0.0281 Normal cell enhancement High speed 2H 15 0.0070 Small cell 2H 15 0.0117 Normal cell 2H 15 0.0164 Normal cell 2H 15 0.0305 Normal cell 2H 15 0.0404 Normal cell 2H 15 0.0667 Normal cell Figure 3.5.6 General structure of the RACH preamble. 3.5 NR Physical Layer PRACH set PRACH set PRACH set Figure 3.5.7 Association of SS/PBCH blocks with PRACH. PRACH format. In contrast to LTE, the length of an OFDM symbol in the PRACH preamble equals the length of a data OFDM symbol. Moreover, due to the OFDM symbol repetition in the new preamble formats, the last part of each OFDM symbol acts as a CP for the next OFDM symbol, thus providing several advantages as discussed above. Similar to LTE, each sequence of the PRACH preamble is based on a Zadoff-Chu sequence, which offers good autocorrelation and power efficiency properties. For scenarios with multi-beam transmission of SS/PBCH blocks, it is necessary to apply the same beamforming for PRACH reception at the gNB as was used for the correspond- ing SS/PBCH transmission to achieve better coverage. As a result of this requirement, NR defines an association between one or multiple SS/PBCH blocks to one PRACH transmis- sion resource occasion, SO the gNB can use for PRACH reception the same beamforming as for SS/PBCH transmission (see Figure 3.5.7). A UE selects a PRACH resource for sub- sequent PRACH preamble transmission based on the detected SS/PBCH block by using a predefined association rule (3GPP TS 38.213). The PRACH resource configuration informa- tion is signaled in SIB1 (System Information Block 1). In addition to synchronization and initial access, PRACH can be also used for other purposes, including new features not supported in LTE such as transition from RRC_INACTIVE state, establishment of time align