RADIO NETWORK SYSTEM, RADIO BASE STATION AND HANDOVER CONTROL METHOD USED FOR THE SAME

摘要

A radio network system, a radio BS, and a handover control method used for the same are provided to reduce the loss or redundancy of data during data transceiving in the radio BS and implement smooth handover in determining the execution of UE-led handover. When a handover destination node B 2-1 receives the processed frame number from a handover origin node B 2-0, it compares u-plane data frame number nR that is transferred from the handover origin node B 2-0 with received frame number NRL for which Ack was returned to the UE 1-0 last and determines whether the u-plane data frame number nR is smaller than the received frame number NRL or not. If the u-plane data frame number nR is bigger than the received frame number NRL, the handover destination node B 2-1 sends UL transferred data from the handover origin node B 2-0 to the gateway. If the u-plane data frame number nR is smaller than the received frame number NRL, the handover destination node B 2-1 discards the UL transferred data from the handover origin node B 2-0. When the handover destination node B 2-1 receives the processed frame number from the handover origin node B 2-0, it compares the u-plane data frame number nT that is transferred from the handover origin node B 2-0 with the sent frame number NTL that was sent to the UE 1-0 last and determines whether the u-plane data frame number nT is smaller than the sent frame number NTL or not(S11). If the u-plane data frame number nT is bigger than the sent frame number NTL, the handover destination node B 2-1 sends DL transferred data from the handover origin node B 2-0 to the UE 1-0(S12). If the u-plane data frame number nT is smaller than the sent frame number NTL, the handover destination node B 2-1 discards the DL transferred data from the handover origin node B 2-0(S13).