Enhanced L1/L2-Triggered Mobility Management with Early CSI Acquisition in 5G-Advanced/6G

The L1/L2-triggered mobility (LTM) technique, which supports beam and cell-level mobility and can significantly reduce handover (HO) interruption time, is expected to be defined as a baseline mobility technique for 5G-Advanced and 6G. However, as the HO decision criteria in LTM changes to an instantaneous value-based L1 measurement, it is expected that the problem of HO interruption due to frequent occurrence of HO will increase. Even if LTM is introduced, there is still a weakness in commercial systems where the data rate temporarily decreases due to conservative link adaptation behavior caused by the absence of initial channel state information (CSI) immediately after HO. In this paper, we propose an improved mobility management method that can respond to various signal degradation situations by simultaneously utilizing L1 measurements and L2 filtered measurements. Additionally, we propose an early CSI acquisition scheme that can acquire the CSI of the target cell before HO execution and reports the early acquired CSI to the target cell without any delay immediately after the HO. The result of the system-level simulation shows that proposed scheme reduces HO failure ratio by about 31%, and prevents a temporary low data rate due to the absence of initial CSI.