DRX cycle
defines
the periodicity of the DRX process.
The longer the DRX cycle, the longer the UE is in a sleep state, but the longer the delay before the UE can respond to a paging message.
DRX cycle length = 2^k frames for FDD mode
where k is DRX cycle length coefficient.
The paging occasion
is
the SFN of the frame of which the UE must monitor the PICH to see whether a paging message is being sent to the UE.
For FDD,
paging occasion (SFN) = (IMSI div K) mod (DRX cycle length) + n* DRX cycle length
where n=0, 1, 2, up to a maximu such that SFN is valid [...]
Cell_PCH
is
one of states in RRC connected mode.
In Cell_PCH, the UE has no uplink resources. The UE monitors the paging channel using the assigned discontinous reception (DRX) parameters.
The UE will entern into Cell_FACH
1. when it detects the cell change, it performs cell update in Cell_FACH
2. when it is paged by the UTRAN
