Telecommunications network

1. A method for operating a mobile communication network, in which user data are transmitted between a mobile station and a first base station, the method comprising

combining the user data into data units before transmitting them; and

storing, for the transmission of the data units, transmission specific information corresponding to transmission specific information which is stored in the mobile station, in a first network unit, the first network unit having a protocol level higher than a protocol level of the first base station, the transmission specific information describing an actual status of the transmission;

wherein in the event of a hand-over of a connection to the mobile station from the first base station to a second base station associated with a second network unit having a protocol level higher than a protocol level of the second base station, signaling information establishes whether a transmission protocol created in the second network unit is to be reset to a starting state or whether the existing, already built-up transmission specific information is to be transferred from the first network unit to the second network unit such that the transmission of the data units may be continued after the handing over essentially directly from the state as it existed immediately before the handing over.

2. The method of claim 1 , further comprising:

adding control information to the data units prior to their transmission, the control information being coded prior to the transmission by differential encoding and wherein for the coding as well as for decoding of the control information, wherein a code book is created at the first network unit, the code book having identical content to a code book created at the mobile station and wherein in the course of the hand-over of the connection the transmission specific information in the first network unit code book is transferred to the second network unit.

3. The method of claim 1 , further comprising:

transferring, before or during a connection establishment for the transmission of data units between the mobile station and the first base station, a first signaling information generated by the mobile station to the first network unit to inform the first network unit whether, in the case of a connection hand-over to a base station having a new higher protocol level network unit different from the first network unit, the transmission specific information should be transferred to the new network unit.

4. The method of claim 1 , further comprising:

transferring, before or during the connection hand-over a second signaling information generated by the mobile station, to the first network unit to inform the first network unit whether in this connection hand-over, the transmission specific information should be transferred to the second network unit.

5. The method of claim 1 , wherein data units buffered in the first network unit for control purposes are transferred to the second network unit with the transmission specific information.

6. The method of claim 1 , wherein in the event of a connection hand-over, the transmission specific information are transferred from a unit of a convergence protocol layer of the first network unit to a unit of a convergence protocol layer of the second network unit.

7. The method of claim 1 , wherein in the event of a connection hand-over, the transmission specific information is transmitted over a fixed network between the first network unit and the second network unit.

8. The method of claim 1 , further comprising:

transmitting, before or during a connection establishment for the transmission of data units between the mobile station and the first base station, first signaling information from the first network unit to the mobile station to inform the mobile station whether, in the event of a connection hand-over to a base station having a new higher protocol level network unit different from the first network unit, the transmission specific information should be transferred to the new network unit.

9. The method of claim 1 , further comprising:

transmitting, before or during a connection hand-over, a second signaling information from the first network unit to the mobile station to inform the mobile station whether in this connection hand-over the transmission specific information should be transferred to the second network unit.

10. A mobile telephone network, comprising:

a plurality of base stations; and

a plurality of network units, the network units each having an assigned hierarchy level;

wherein the plurality of base stations provide an air interface to connected mobile stations and wherein the base stations of the network are logically connected via the network units, the network units processing connections according to respective protocol layers and wherein the network units are sub-divided according to a respective protocol layer level at which the network unit operates to form higher level network units and at least one highest level network unit, the higher level network units operating according to a packet data convergence protocol layer, and

wherein a higher level network unit associated with a first base station is arranged to store transmission related information to implement the packet data convergence protocol for handling a connection to a mobile station and in the event of a hand-over of the connection to a second base station to transfer the transmission related information to a higher level network unit associated with the second base station.

11. The mobile telephone network of claim 10 , wherein the higher level network unit associated to the first base station is arranged to generate a message for transmission to a mobile station in the event of a hand-over of a connection to that mobile station to a second base station associated with a different higher level network unit, the message including information to inform the mobile station whether the transmission related information is to be transferred to the different higher level network unit.