FIELD: radio engineering, communication.
SUBSTANCE: one embodiment provides a method in a first base (Node_B_S) station adapted to receive media access control layer packet data units (MAC-d; PDU 101, 102, 104, 105) from a radio network controller (RNC) relating to at least a traffic flow relating to a given user entity (UE_Q) and forward (MAC-hs/MAC-ehs) such packet data units to said user entity. The transmission to the given user entity is adapted to be potentially handed over to at least a second radio base station (Node B_T), the method being characterised in the following steps: the first base station (Node_B_S) continuously updates (12, 33, 335, 41) at least a data structure (UNACK_MACD_CNT) relating to media access control layer packet data units (MAC-d PDU) of a priority queue of the user entity, where packet data units are recently transmitted from a protocol layer (RLC) in the radio network controller (RNC RLC) whereby at least some of said packet data units may not be received by a corresponding protocol layer (RLC) in the user entity (UE_Q) yet, - the first base station, upon receiving a predetermined signal (UNACK_MACD_REQ (108)) from the radio network controller requests the data structure, transmits (41, 110) a current value of said data structure (UNACK_MACD_CNT) to the radio network controller (RNC).
EFFECT: suppressing negative effects associated with discarded packet data units which arise when a user entity is involved in data reception by performing handover between base stations.
19 cl, 16 dwg
