Multi-stage sidelink control information

1. A method of controlling sidelink radio transmissions in a wireless communication network, the method comprising:

a radio device receiving first sidelink control information from a further radio device, wherein the first sidelink control information comprises information for sensing-based allocation of radio resources for a sidelink radio transmission;

based on assistance information stored in the radio device and the received first sidelink control information, the radio device determining a configuration for transmission of second sidelink control information;

based on the determined configuration for transmission of the second sidelink control information, the radio device receiving the second sidelink control information from the further radio device; and

based on the received second sidelink control information, the radio device receiving a sidelink radio transmission from the further radio device.

2. The method according to claim 1 ,

wherein the assistance information defines multiple candidate configurations for transmission of the second sidelink control information; and

wherein the first sidelink control information identifies the configuration for transmission of the second sidelink control information among the candidate configurations.

3. The method according to claim 1 ,

wherein the second sidelink control information comprises information indicating at least one of: radio resources to be used for the sidelink radio transmission a modulation and/or coding scheme to be used for the sidelink radio transmission, one or more retransmission parameters of the sidelink radio transmission, and a priority level of the sidelink radio transmission.

4. The method according to claim 1 ,

wherein a first part of the configuration for transmission of the second sidelink control information is defined by the first sidelink control information and a second part of the configuration for transmission of the second sidelink control information is defined by the assistance information.

5. The method according to claim 2 ,

wherein the first sidelink control information comprises an index identifying the configuration for transmission of the second sidelink control information among the candidate configurations.

6. The method according to claim 1 , wherein the radio device comprises a vehicle.

7. A method of controlling sidelink radio transmissions in a wireless communication network, the method comprising:

based on assistance information stored in a radio device, the radio device determining first sidelink control information, the assistance information relating the first sidelink control information to a configuration for transmission of second sidelink control information, the first sidelink control information comprising information for sensing-based allocation of radio resources for a sidelink radio transmission;

the radio device sending the first sidelink control information to a further radio device;

based on the configuration, the radio device sending the second sidelink control information to the further radio device; and

based on the second sidelink control information, the radio device sending a sidelink radio transmission to the further radio device.

8. The method according to claim 7 ,

wherein the assistance information defines multiple candidate configurations for transmission of the second sidelink control information; and

wherein the first sidelink control information identifies the configuration for transmission of the second sidelink control information among the candidate configurations.

9. The method according to claim 7 ,

wherein the second sidelink control information comprises information indicating at least one of: radio resources to be used for the sidelink radio transmission, a modulation and/or coding scheme to be used for the sidelink radio transmission, one or more retransmission parameters of the sidelink radio transmission, and a priority level of the sidelink radio transmission.

10. The method according to claim 7 ,

wherein a first part of the configuration for transmission of the second sidelink control information is defined by the first sidelink control information and a second part of the configuration for transmission of the second sidelink control information is defined by the assistance information.

11. The method according to claim 8 ,

wherein the first sidelink control information comprises an index identifying the configuration for transmission of the second sidelink control information among the candidate configurations.

12. The method according to claim 7 , wherein the radio device comprises a vehicle.

13. A computer program product comprising a non-transitory computer readable medium having program code to be executed by at least one processor of a radio device, whereby execution of the program code causes the radio device to perform a method according to claim 1 .

14. A computer program product comprising a non-transitory computer readable medium having program code to be executed by at least one processor of a radio device, whereby execution of the program code causes the radio device to perform a method according to claim 7 .

15. A radio device for a wireless communication network, the radio device comprising:

a processor; and

a memory coupled with the processor, the memory containing instructions executable by the processor whereby the radio device is operative to:

receive first sidelink control information from a further radio device, the first sidelink control information comprising information for sensing-based allocation of radio resources for a sidelink radio transmission;

based on assistance information stored in the radio device and the received first sidelink control information, determine a configuration for transmission of second sidelink control information;

based on the determined configuration for transmission of the second sidelink control information, receive the second sidelink control information from the further radio device; and

based on the received second sidelink control information, receive a sidelink radio transmission from the further radio device.

16. The radio device according to claim 15 ,

wherein the assistance information defines multiple candidate configurations for transmission of the second sidelink control information; and

wherein the first sidelink control information identifies the configuration for transmission of the second sidelink control information among the candidate configurations.

17. The radio device according to claim 15 ,

wherein the second sidelink control information comprises information indicating at least one of: radio resources to be used for the sidelink radio transmission a modulation and/or coding scheme to be used for the sidelink radio transmission, one or more retransmission parameters of the sidelink radio transmission, and a priority level of the sidelink radio transmission.

18. The radio device according to claim 15 ,

wherein a first part of the configuration for transmission of the second sidelink control information is defined by the first sidelink control information and a second part of the configuration for transmission of the second sidelink control information is defined by the assistance information.

19. The radio device according to claim 16 ,

wherein the first sidelink control information comprises an index identifying the configuration for transmission of the second sidelink control information among the candidate configurations.

20. The radio device according to claim 15 , wherein the radio device comprises a vehicle.

21. A radio device for a wireless communication network, the radio device comprising:

a processor; and

a memory coupled with the processor, the memory containing instructions executable by the processor whereby the radio device is operative to:

based on assistance information stored in the radio device, determine first sidelink control information, the assistance information relating the first sidelink control information to a configuration for transmission of second sidelink control information, wherein the first sidelink control information comprises information for sensing-based allocation of radio resources for a sidelink radio transmission;

send the first sidelink control information to a further radio device;

based on the configuration, send the second sidelink control information to the further radio device; and

based on the second sidelink control information, send a sidelink radio transmission to the further radio device.

22. The radio device according to claim 21 ,

wherein the assistance information defines multiple candidate configurations for transmission of the second sidelink control information; and

wherein the first sidelink control information identifies the configuration for transmission of the second sidelink control information among the candidate configurations.

23. The radio device according to claim 21 ,

wherein the second sidelink control information comprises information indicating at least one of: radio resources to be used for the sidelink radio transmission, a modulation and/or coding scheme to be used for the sidelink radio transmission, one or more retransmission parameters of the sidelink radio transmission, and a priority level of the sidelink radio transmission.

24. The radio device according to claim 21 ,

wherein a first part of the configuration for transmission of the second sidelink control information is defined by the first sidelink control information and a second part of the configuration for transmission of the second sidelink control information is defined by the assistance information.

25. The radio device according to claim 22 ,

wherein the first sidelink control information comprises an index identifying the configuration for transmission of the second sidelink control information among the candidate configurations.

26. The radio device according to claim 21 , wherein the radio device comprises a vehicle.