The present invention introduces a beam-based UE mobility state estimate for power saving purposes, based on monitoring the distinct beam(s) (302) detected by the UE. In other words, the number N of distinct serving beams changed by the UE within a time window T is monitored (302) against the configured threshold values. If N is below a first threshold value “Thr1”, a low/stationary mobility state is determined (303) and the UE applies a first measurement configuration (305) associated with the low/stationary mobility state. If N is between first and second threshold values “Thr1” and “Thr2”, a medium mobility state is determined (304) and the UE applies a second measurement configuration (306) associated with the medium mobility state. If N is above the second threshold value “Thr2”, a high mobility state is determined and the UE applies a third measurement configuration associated with the high mobility state.