PRACH --- originator

prach ofdm Generation of symbols ：

prach Of preamble id How did you get it ？

A cycle offset is Cv, The length is L_RA Of ZC Sequence , This sequence will determine a preamble id .
For a single ue Come on , Every ue Use one preamble id
For a base station , The biggest support 64 individual preamble id, That is to support 64 Of ue Access at the same time , We see , One L_RA Of ZC Sequences do not necessarily have 64 individual Cv, If not enough , One logic index i Corresponding to one u , One u Corresponding to produce L_RA Of length ZC Sequence , If the first one ZC Insufficient sequence 64 individual preamble id
It would be i+1 The corresponding new u produce （38.211 6.3.3.1-3 and 6.3.3.1-4）.