PRACH Configuration — Rural Macro Cell

An operator is lighting up a rural macro cell to cover a long highway stretch. The cell runs FDD on 700 MHz (band n28): a 20 MHz carrier at 15 kHz subcarrier spacing, 106 resource blocks. Physical cell radius is 22 km — you need preambles that survive the long round-trip delay. Peak load expected: 300 UEs in cell, medium access pressure. The plan needs a PRACH occasion in every 10 ms radio frame: one in time per frame is enough, and msg1-FDM sets how many sit side by side in frequency. A neighbour site (operated by your partner) occupies logical root-sequence indices 90..140. The plan keeps a guard band of 16 indices either side of that range, and your root sequences must stay clear of it. Your job: pick the preamble format, PRACH configuration index, zero-correlation-zone index (zeroCorrelationZoneConfig, which selects the cyclic shift N_CS), root-sequence index, PRACH frequency offset and msg1-FDM. Live rule checks will tell you what still violates.