Method and device for generating a rate compatible code

1. A method for generating a serial-concatenated channel-code at a predetermined code rate for transmission of a message via a channel, including a radio channel, which comprises the steps of:

receiving a message signal to be coded;

first channel-coding of the message signal by a first channel-coding stage, the first channel-coding stage being a systematic convolution coder outputting the message signal to include a systematic data sequence and a redundant data sequence;

puncturing the systematic data sequence and the redundant data sequence;

second channel-coding of the message signal by a second channel-coding stage resulting in a channel-coded message signal, the second channel-coding stage disposed on an output side of the first channel-coding stage;

setting a code rate of the channel-coded message signal in a predetermined manner, using a controllable puncturer disposed in a signal path between the first and second channel-coding stages; and

outputting the channel-coded message signal which has passed through both the first and second channel-coding stages.

2. The method according to claim 1 , which comprises controlling the controllable puncturer in dependence on a service to be transmitted.

3. The method according to claim 1 , which comprises controlling the controllable puncturer in dependence on an acknowledgement signal that is characteristic of a receiver response.

4. The method according to claim 3 , which comprises controlling the controllable puncturer to set the code rate to be just sufficient to ensure a maximum predetermined bit error rate at a receiving end.

5. The method according to claim 1 , which comprises forming the message signal from data packets in order to provide a packet-switching data transmission.

6. The method according to claim 5 , which comprises:

requesting in a receiver end, a further transmission of that data part of a packet which has not been received in an event of the packet not being transmitted completely via the channel; and

during the further transmission, only the data part which was not transmitted is transmitted, with a lower code rate being set.

7. The method according to claim 5 , which comprises:

requesting in a receiver end, a further transmission of that data part of a packet that has been received with errors in an event of the packet being transmitted with errors via the channel; and

during the further transmission, only the data part transmitted with errors is transmitted, with a lower code rate being set.

8. The method according to claim 1 , which comprises generating the channel-coded message signal using a turbo code.

9. A device for channel-coding a message signal that is to be transmitted via a channel, including a radio channel, the device comprising:

a first channel-coding stage for receiving the message signal and subjecting the message signal to a first coding process, said first channel-coding stage having a systematic convolution coder outputting the message signal to include a systematic data sequence and a redundant data sequence;

a second channel-coding stage disposed in a signal path downstream from said first channel-coding stage; and

a controllable puncturer for setting a code rate of a channel-coded message signal output from the device in a manner being predetermined, said controllable puncturer disposed in said signal path between said first channel-coding stage and said second channel-coding stage, said controllable puncturer puncturing the systematic data sequence and the redundant data sequence.

10. The device according to claim 9 , wherein said second channel-coding stage is a convolution coder.

11. The device according to claim 9 , wherein:

at least said first channel-coding stage is a recursive, systematic convolution coder with a first output for outputting the systematic data sequence and a second output for outputting the redundant data sequence; and

said controllable puncturer is one of two controllable puncturers including a first controllable puncturer connected to said first output and a second controllable puncturer connected to said second output.

12. The device according to claim 9 , including an interleaver disposed in said signal path between said first channel-coding stage and said second channel-coding stage.

13. The device according to claim 12 , including a further interleaver disposed in said signal path after said second channel-coding stage.