A method and apparatus are provided for enabling a UE to perform accurate
and efficient cell reselection in a cellular mobile communications
system. If reselection to the same cell is repeated, the UE releases
itself from a high-speed UE state or excludes the number of reselections
to the same cell from the number of cell changes counted for a duration
set for deciding as to the high-speed UE state, according to a ping-pong
duration threshold and a ping-pong occurrence number threshold. The UE
uses a non-scaled down cell reselection time limit in a non-high-speed UE
state, and a scaled-down cell reselection time limit in the high-speed UE
state. Thus, the UE reselects to a non-serving cell having the highest
ranking continuously for the cell reselection time limit.