Method and apparatus for sidelink transmission control

1. A method implemented at a first user equipment (UE) which supports a first radio access technology comprising:

determining a sidelink transmission mode for transmitting, the sidelink transmission mode being one of a first mode corresponding to the first radio access technology and a second mode corresponding to a second radio access technology; and

transmitting a sidelink signal according to the sidelink transmission mode using a sidelink resource configured by a network node which serves the first UE;

wherein determining the sidelink transmission mode comprises:

detecting the sidelink signal from other sidelink transmissions;

determining which sidelink transmission mode is used for the other sidelink transmissions;

in response that any of the other sidelink transmissions uses the second mode, determining the sidelink transmission mode as the second mode; and

in response that all of the other sidelink transmissions use the first mode, determining the sidelink transmission mode as the first mode.

2. The method according to claim 1 , wherein the determining a sidelink transmission mode comprises:

determining which radio access technology is supported by at least one second UE in proximity;

in response that any of the at least one second UE supports the second radio access technology, determining the sidelink transmission mode as the second mode; and

in response that all of the at least one second UE support the first radio access technology, determining the sidelink transmission mode as the first mode.

3. The method according to claim 2 , wherein the determination of the radio access technology supported by the at least one second UE is based on capability information of the at least one second UE which has been obtained by the first UE.

4. The method according to claim 1 , wherein the sidelink transmission mode is determined based on pre-configuration of the first mode or the second mode for the first UE.

5. The method according to claim 1 , wherein the sidelink transmission mode is determined based on a transmission requirement for the sidelink transmission.

6. The method according to claim 1 , wherein the sidelink transmission mode is determined based on a resource configuration dedicated to the first mode or the second mode for the first UE.

7. The method according to claim 1 , wherein the network node supports the second radio access technology;

and wherein transmitting the sidelink signal comprises:

in response to the determination of the sidelink transmission mode as the first mode,

adapting configuration of the sidelink resource for the first mode; and

transmitting the sidelink signal using the adapted sidelink resource according to the first mode; and

in response to the determination of the sidelink transmission mode as the second mode, transmitting the sidelink signal using the sidelink resource according to the second mode.

8. The method according to claim 7 , wherein the first UE further transmits additional signals to span the sidelink resource.

9. The method according to claim 1 , wherein the first UE is configured with a first sidelink resource for the first mode and a second sidelink resource for the second mode;

wherein transmitting the sidelink signal comprises:

in response to the determination of the sidelink transmission mode as the first mode, transmitting the sidelink signal using the first sidelink resource according to the first mode; and

in response to the determination of the sidelink transmission mode as the second mode, transmitting the sidelink signal using the second sidelink resource according to the second mode.

10. The method according to claim 1 , wherein the first UE is configured with the sidelink resource within which a part of parameters are assigned with a first value for the first mode and a second value for the second mode and other parameters are assigned with a value common to the first and second modes;

wherein transmitting the sidelink signal comprises:

in response to the determination of the sidelink transmission mode as the first mode, transmitting the sidelink signal within the sidelink resource using the corresponding parameters for the first mode according to the first mode; and

in response to the determination of the sidelink transmission mode as the second mode, transmitting the sidelink signal within the sidelink resource using the corresponding parameters for the second mode according to the second mode.

11. The method according to claim 1 , further comprising:

determining which sidelink transmission mode is to be used for receiving; and

receiving a sidelink signal using the determined sidelink transmission mode.

12. An apparatus in a first user equipment (UE) which supports a first radio access technology comprising:

a processor; and

a memory, said memory containing instructions executable by said processor, whereby said apparatus is operative to:

determine a sidelink transmission mode for transmitting, the sidelink transmission mode being one of a first mode corresponding to the first radio access technology and a second mode corresponding to a second radio access technology; and

transmit a sidelink signal according to the sidelink transmission mode using a sidelink resource configured by a network node which serves the first UE;

wherein the apparatus is operative to determine the sidelink transmission mode by:

detecting the sidelink signal from other sidelink transmissions;

determining which sidelink transmission mode is used for the other sidelink transmissions;

in response that any of the other sidelink transmissions uses the second mode, determining the sidelink transmission mode as the second mode; and

in response that all of the other sidelink transmissions use the first mode, determining the sidelink transmission mode as the first mode; or

determining which radio access technology is supported by at least one second UE in proximity;

in response that any of the at least one second UE supports the second radio access technology, determining the sidelink transmission mode as the second mode; and

in response that all of the at least one second UE support the first radio access technology, determining the sidelink transmission mode as the first mode.

13. The apparatus according to claim 12 , wherein the apparatus is operative to determine which radio access technology is supported by the at least one second UE in proximity based on a capability information of the at least one second UE which has been obtained by the first UE.

14. The apparatus according to claim 12 , wherein the apparatus is operative to determine the sidelink transmission mode based on any of:

pre-configuration of the first mode or the second mode for the first UE;

a transmission requirement for the sidelink transmission; or

a resource configuration dedicated to the first mode or the second mode for the first UE.

15. The apparatus according to claim 12 , wherein the network node supports the second radio access technology;

and wherein the apparatus is operative to transmit the sidelink signal by:

in response to the determination of the sidelink transmission mode as the first mode,

adapting configuration of the sidelink resource for the first mode; and

transmitting the sidelink signal using the adapted sidelink resource according to the first mode; and

in response to the determination of the sidelink transmission mode as the second mode, transmitting the sidelink signal using the sidelink resource according to the second mode.

16. The apparatus according to claim 12 , wherein the first UE is configured with a first sidelink resource for the first mode and a second sidelink resource for the second mode;

wherein the apparatus is operative to transmit the sidelink signal by:

in response to the determination of the sidelink transmission mode as the first mode, transmitting the sidelink signal using the first sidelink resource according to the first mode; and

in response to the determination of the sidelink transmission mode as the second mode, transmitting the sidelink signal using the second sidelink resource according to the second mode.

17. The apparatus according to claim 12 , wherein the UE is configured with a sidelink resource within which a part of parameters are assigned with a first value for the first mode and a second value for the second mode and other parameters are assigned with a value common to the first and second modes;

and wherein the apparatus is operative to transmit the sidelink signal by:

in response to the determination of the sidelink transmission mode as the first mode, transmitting the sidelink signal within the sidelink resource using the corresponding parameters for the first mode according to the first mode; and

in response to the determination of the sidelink transmission mode as the second mode, transmitting the sidelink signal within the sidelink resource using the corresponding parameters for the second mode according to the second mode.

18. The apparatus according to claim 12 , wherein the apparatus is further operative to:

determine which sidelink transmission mode is to be used for receiving; and

receive the sidelink signal using the determined sidelink transmission mode.

19. The apparatus according to claim 18 , wherein the apparatus is operative to determine which sidelink transmission mode is to be used for receiving by:

receiving a second sidelink signal;

decoding the received second sidelink signal using the first mode and the second mode respectively;

in response to the received second sidelink signal is successfully decoded using the first mode, determining the first mode is to be used for receiving; and

in response to the received second sidelink signal is successfully decoded using the second mode, determining the second mode is to be used for receiving.

20. The apparatus according to claim 18 , wherein the UE is configured with a receiving resource, a first transmission resource for the first mode and a second transmission resource for the second mode, the receiving resource covering the first and second transmission resource,

and wherein the apparatus is operative to determine which sidelink transmission mode is to be used for receiving by:

detecting whether a second sidelink signal is received using the first mode or the second mode within the first transmission resource;

in response to the detection of the receipt of the second sidelink signal, determining the first mode or the second mode is to be used within the first transmission resource for receiving;

detecting whether the second sidelink signal is received using the first mode or the second mode within the second transmission resource;

in response to the detection of the receipt of the second sidelink signal, determining the first mode or the second mode is to be used within the second transmission resource for receiving;

detecting whether the sidelink signal is received using the first mode or the second mode within the remaining of the receiving resource; and

in response to the detection of the receipt of the second sidelink signal, determining the first mode or the second mode is to be used within the remaining of the receiving resource for receiving.

21. The apparatus according to claim 18 , wherein the UE is configured with a first receiving resource for the first mode and a second receiving resource for the second mode,

and wherein the apparatus is operative to determine which sidelink transmission mode is to be used for receiving by:

detecting whether a second sidelink signal is received within the first receiving resource or the second receiving source;

in response to the detection that the second sidelink signal is received within the first receiving resource, determining the first mode is to be used for receiving; and

in response to the detection that the second sidelink signal is received within the first receiving resource, determining the first mode is to be used for receiving.