With regard to competitive and non-competitive access, which of the following descriptions are correct? (Multiple choice)
A . RRC reconstruction after out-of-synchronization of wireless links generally adopts non-competitive mode
B . a random-access preamble sequence in a cell has 64
C . Switching to a new cell generally adopts a competitive mode
D . Non-competitive access, preamble adopts the allocation method to avoid competition conflicts.
Answer: BCD