| 摘要 |
The invention relates to radio systems and particularly to non-transparent data transmission in a mobile communication system where a mobile services switching center and a radio access network belong to different system generations. A second-generation mobile services switching center is also provided with a protocol unit supporting a radio link protocol of a third-generation radio access network. In such a case the radio link protocol is set up between the mobile station and the mobile services switching center without a radio link protocol conversion in an interworking unit of the radio access network. The radio access network merely transmits the radio link protocol transparently between the mobile station and the mobile services switching center, i.e. it extends the protocol to the mobile services switching center. When a handover of a non-transparent call is carried out between two radio access networks, the same radio link protocol units (in the mobile station and in the mobile services switching center) also remain after the handover. Possibly ongoing sequences of selective retransmissions and retransmission requests of the radio link protocol are not interrupted or disturbed, wherefore it is also possible to avoid the manipulation of buffer synchronization which might possibly lead to retransmission complications and loss or doubling of data as a result of the handover. |
