초록 ▼

In a radio data transmission system which transmits data in cell form, the risk of cell loss or the risk of out-of-ordering during handover can be diminished by synchronizing the cell transmission between the new (50) and the old (40) base stations. The old base station (40) delivers to the new base

In a radio data transmission system which transmits data in cell form, the risk of cell loss or the risk of out-of-ordering during handover can be diminished by synchronizing the cell transmission between the new (50) and the old (40) base stations. The old base station (40) delivers to the new base station (50) and/or the switch (51), information on the last cell that was transmitted successfully and in the right order through the old base station, whereby the new base station continues the transmission by starting from the first failed cell. Cells need not be identified one by one if group numbering is applied in which the first or the last cell of a given group (31, 32, 33, 34) or a given counter cell is numbered, and the rest can be indicated, where necessary, by counting the distance from the numbered cell.

대표청구항 ▼

[ We claim:] [1.] A method for implementing a handover in a data transmission system that comprises a switch (51) and a first (40) and a second (50) base station that are affiliated with the switch, anda mobile unit (41) that is affiliated wirelessly with the base stations,and wherein the operation

[ We claim:] [1.] A method for implementing a handover in a data transmission system that comprises a switch (51) and a first (40) and a second (50) base station that are affiliated with the switch, anda mobile unit (41) that is affiliated wirelessly with the base stations,and wherein the operation of the data transmission system comprises the transmission of data as cells of a given size, and the handover comprises the transmission of said cells of data first between the mobile unit (41) and the first base station (40) and, after that, between the mobile unit (41) and the second base station (50), said method comprising the steps of:transmitting a flow of said cells between the first base station (40) and the mobile unit (41);detecting the first cell that is not successfully transmitted between the first base station and the mobile unit and subsequent cells that are not successfully transmitted, to determine which cells have been successfully transmitted between the first base station and the mobile unit; andproviding information from the first base station (40) to the switch (51) and/or the second base station (50) on which cells have been successfully transmitted between the first base station and the mobile unit.