Wireless Oom

Cell_DCH
is
One of states in connected mode.
The UE is assigned a dedicated physical channel (DPCH) either in response to the RRC connection request or via some UTRAN controlled bearer reconfiguration procedure.
If UE releases (or asked to release by the network) dedicated channel, the UE can move to any other states in RRC connected mode (Cell_FACH, Cell_PCH, [...]