当从连接状态回到空闲状态的时候需要进行小区搜索，协议的一段描述我觉得不准确：
When returning to idle mode, the UE shall use the procedure Cell selection when leaving connected mode in order to find a suitable cell to camp on and enter state Camped normally. If a suitable cell is found, then the AS reports this event to NAS to be capable to perform necessary NAS registration procedures. If no suitable cell is found, the Stored information cell selection procedure shall be used.
从协议的角度是说：离开连接进空闲要进行procedure Cell selection搜索（实际上就是频带扫描），如果没有搜到适合的小区再进行Stored information cell（选择）搜索。可是实际上一般的情况下Stored information cell（选择）就是为了快速搜到小区，所以我认为离开空闲应该先进行Stored information cell（选择），再进行频带扫描！