Method and arrangement for retransmission using HARQ

1. A method in a mobile terminal wirelessly connectable to a radio base station of a mobile telecommunication network that supports at least two Hybrid Automatic Repeat Request (HARQ) operation modes, of which the first HARQ operation mode uses a single Transmission Time Interval (TTI) for transmissions and retransmissions and where the timing relationship between transmissions and retransmissions is pre-determined, said method comprising the steps of:

transmitting information according to the second HARQ operation mode relating to a first HARQ process, by using a first predetermined number of transmission time intervals (TTIs) comprising at least a first TTI and a second TTI, to the radio base station, wherein a redundancy version of the first HARQ process is sent in each TTI;

receiving an indication that the transmitted information was not decoded correctly at the radio base station; and

retransmitting the information according to the second HARQ operation mode relating to the first HARQ process, by using a second predetermined number of TTIs, wherein the retransmission begins at least at a second available retransmission occurrence according to the first HARQ operation mode, subsequent to the first TTI.

2. The method of claim 1 , wherein the retransmission begins at the second available retransmission occurrence according to the first HARQ operation mode, subsequent to the first TTI.

3. The method of claim 1 , wherein the method comprises an initial step of:

receiving information indicating the first or second predetermined number of TTIs to be used for said transmission of information relating to the first HARQ process.

4. The method of claim 1 , wherein the first predetermined number of TTI is equal to the second number of TTIs.

5. The method of claim 1 , wherein the method further comprises the step of:

receiving information via Radio Resource Control (RRC) signaling that a first predetermined number of TTIs comprising at least a first TTI and a second TTI should be used for all transmissions.

6. The method of claim 1 , wherein the indication that the transmitted information was not decoded correctly at the radio base station is an HARQ feedback.

7. A method in a radio base station of a mobile telecommunication network wirelessly connectable to a mobile terminal, the mobile telecommunication network supports at least two Hybrid Automatic Repeat Request (HARQ) operation modes of which the first HARQ operation mode uses a single Transmission Time Interval (TTI) for transmissions and retransmissions and where the timing relationship between transmissions and retransmissions is pre-determined, said method comprising the steps of:

configuring the mobile terminal to transmit information, according to the second HARQ operation mode, relating to a first HARQ process using a first predetermined number of transmission time intervals (TTIs) comprising at least a first TTI and a second TTI, to the radio base station, wherein a redundancy version of the first HARQ process is sent in each TTI, and to retransmit the information, according to the second HARQ operation mode, relating to the first HARQ process using a second predetermined number of TTIs, wherein the retransmission begins at least at a second available retransmission occurrence according to the first HARQ operation mode, subsequent to the first TTI;

receiving information relating to the first HARQ process using the first predetermined number of TTIs comprising at least the first TTI and the second TTI; and

transmitting HARQ feedback in response to the received information on the first determined number of TTIs.

8. The method of claim 7 , wherein the retransmission is configured to begin at the second available retransmission occurrence according to the first HARQ operation mode, subsequent to the first TTI.

9. The method of claim 7 , wherein the configuring step further comprises:

transmitting information indicating the first or second predetermined number of TTIs.

10. The method of claim 9 , wherein the first predetermined number of TTI is equal to the second number of TTIs.

11. The method of claim 10 , wherein the configuring step further comprises:

transmitting information via Radio Resource Control (RRC) signaling that a first predetermined number of TTIs comprising at least a first TTI and a second TTI should be used for all transmissions.

12. A mobile terminal wirelessly connectable to a radio base station of a mobile telecommunication network that supports at least two Hybrid Automatic Repeat Request, HARQ, operation modes of which the first HARQ operation mode uses a single Transmission Time Interval (TTI) for transmissions and retransmissions and where the timing relationship between transmissions and retransmissions is pre-determined, said mobile terminal comprising:

a transmitter for transmitting information according to the second HARQ operation mode relating to a first HARQ process by using a first predetermined number of TTIs comprising at least a first TTI and a second TTI to the radio base station, wherein a redundancy version of the first HARQ process is sent in each TTI; and

a receiver for receiving an indication that the transmitted information was not decoded correctly at the radio base station;

wherein said transmitter is configured for retransmitting the information according to the second HARQ operation mode relating to the first HARQ process by using a second predetermined number of TTIs, and wherein the retransmission begins at least at a second available retransmission occurrence according to the first HARQ operation mode, subsequent to the first TTI.

13. The mobile terminal of claim 12 , wherein the retransmission begins at the second available retransmission occurrence according to the first HARQ operation mode, subsequent to the first TTI.

14. The mobile terminal of claim 12 , wherein the mobile terminal is configured for receiving information indicating the first or second predetermined number of TTIs to be used for said transmission of information relating to the first HARQ process.

15. The mobile terminal of claim 12 , wherein the first predetermined number of TTI is equal to the second number of TTIs.

16. The mobile terminal of claim 12 , wherein the indication that the transmitted information was not decoded correctly at the radio base station is an HARQ feedback.

17. The mobile terminal of claim 12 , wherein the mobile terminal is configured for receiving information via Radio Resource Control (RRC) signaling that a first predetermined number of TTIs comprising at least a first TTI and a second TTI should be used for all its transmissions.

18. A radio base station of a mobile telecommunication network wirelessly connectable to a mobile terminal, the mobile telecommunication network supports at least two Hybrid Automatic Repeat Request, HARQ, operation modes of which the first HARQ operation mode uses a single Transmission Time Interval (TTI) for transmissions and retransmissions and where the timing relationship between transmissions and retransmissions is pre-determined, said radio base station comprising:

a control circuit configured to transmit signaling via a base station transmitter, for configuring the mobile terminal to transmit information, according to the second HARQ operation mode, relating to a first HARQ process using a first predetermined number of transmission time intervals (TTIs) comprising at least a first TTI and a second TTI, to the radio base station, wherein a redundancy version of the first HARQ process is sent in each TTI, and to retransmit the information, according to the second HARQ operation mode, relating to the first HARQ process using a second predetermined number of TTIs, wherein the retransmission begins at least at a second available retransmission occurrence according to the first HARQ operation mode, subsequent to the first TTI; and

a receiver for receiving information relating to the first HARQ process using the first predetermined number of TTIs comprising at least the first TTI and the second TTI;

wherein said control circuit is configured to transmit HARQ feedback, via the transmitter, in response to the received information on the first determined number of TTIs.

19. The radio base station of claim 18 , wherein the retransmission is configured to begin at the second available retransmission occurrence according to the first HARQ operation mode, subsequent to the first TTI.

20. The radio base station of claim 18 , wherein the control circuit is configured to transmit information indicating the first or second predetermined number of TTIs.

21. The radio base station of claim 18 , wherein the first predetermined number of TTI is equal to the second number of TTIs.

22. The radio base station of claim 18 , wherein the control circuit is configured to transmit configuration information via Radio Resource Control (RRC) signaling that the first predetermined number of TTIs comprising at least a first TTI and a second TTI should be used for all transmissions.