Embodiments of the present disclosure provide a method implemented by an access node in a wireless communication system for beam switch, comprising: selecting a transmission mode from a set of predefined transmission modes; transmitting a reference signal to a device according to the selected transmission mode; signaling the selected transmission mode to the device; and receiving, from the device, a mobility measurement report based on the reference signal. By virtue of this method, the signaling overhead for reference signal configuration can be reduced.