Techniques for activating sidelink carrier aggregation during a switch from direct to indirect communication

1 . An apparatus for wireless communication at a first user equipment (UE), comprising:

at least one processor; and

at least one memory coupled with the at least one processor, the at least one memory storing instructions executable by the at least one processor to cause the apparatus to:

receive, from a second UE, a first set of one or more synchronization signals via a first component carrier and a second set of one or more synchronization signals via a second component carrier;

transmit a first measurement report indicative of one or more first measurements on the first set of one or more synchronization signals and a second measurement report indicative of one or more second measurements on the second set of one or more synchronization signals; and

receive a control message associated with indirect communication between the first UE and a network entity via the second UE, wherein the control message includes a set of parameters for activating sidelink carrier aggregation between the first UE and the second UE based at least in part on the one or more first measurements indicated by the first measurement report and the one or more second measurements indicated by the second measurement report, wherein the sidelink carrier aggregation is activated based at least in part on a switch from direct communication between the first UE and the network entity to the indirect communication between the first UE and the network entity.

2 . The apparatus of claim 1 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

establish a sidelink connection between the first UE and the second UE based at least in part on the control message, wherein the control message further includes a second set of parameters associated with the switch from the direct communication between the first UE and the network entity to the indirect communication between the first UE and the network entity via the second UE.

3 . The apparatus of claim 1 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

receive a second control message associated with the switch from the direct communication between the first UE and the network entity to the indirect communication between the first UE and the network entity via the second UE, wherein the second control message includes a second set of parameters associated with the switch; and

establish a sidelink connection between the first UE and the second UE based at least in part on the second control message.

4 . The apparatus of claim 1 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

receive, from the network entity, a request to measure the second set of one or more synchronization signals via the second component carrier and to transmit the second measurement report, wherein receiving the second set of one or more synchronization signals and transmitting the second measurement report is based at least in part on receiving the request.

5 . The apparatus of claim 1 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

transmit a second control message responsive to the control message, wherein the second control message indicates a completion of a sidelink connection between the first UE and the second UE and indicates the activation of the sidelink carrier aggregation for the sidelink connection.

6 . The apparatus of claim 1 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

receive, from the second UE and in accordance with a sidelink connection establishment procedure, a random access channel message based at least in part on a radio frequency band of a sidelink connection between the first UE and the second UE; and

transmit, to the second UE, a random access channel response message based at least in part on receiving the random access channel message.

7 . The apparatus of claim 1 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

transmit data to, or receive data from, the network entity via the second UE in accordance with the indirect communication between the first UE and the network entity via the second UE and the sidelink carrier aggregation between the first UE and the second UE.

8 . An apparatus for wireless communication at a first user equipment (UE), comprising:

at least one processor; and

at least one memory coupled with the at least one processor, the at least one memory storing instructions executable by the at least one processor to cause the apparatus to:

transmit, to a second UE, a first set of one or more synchronization signals via a first component carrier and a second set of one or more synchronization signals via a second component carrier;

establish a sidelink connection between the first UE and the second UE in accordance with a switch from direct communication between the second UE and a network entity to indirect communication between the second UE and the network entity via the first UE;

receive, from the second UE, a measurement report indicative of one or more measurements on the second set of one or more synchronization signals; and

transmit data to, or receive data from, the second UE in accordance with the indirect communication between the second UE and the network entity via the first UE and a sidelink carrier aggregation between the first UE and the second UE, wherein the sidelink carrier aggregation is:

based at least in part on the first set of one or more synchronization signals and on the one or more measurements of the second set of one or more synchronization signals indicated by the measurement report, and

activated based at least in part on the switch from the direct communication between the second UE and the network entity to indirect communication between the second UE and the network entity via the first UE.

9 . The apparatus of claim 8 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

receive, from the network entity, a request to transmit the second set of one or more synchronization signals via the second component carrier, wherein transmitting the second set of one or more synchronization signals via the second component carrier is based at least in part on receiving the request.

10 . The apparatus of claim 9 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

receive, from the network entity, a sidelink carrier aggregation capability inquiry message; and

transmit, to the network entity in response to the sidelink carrier aggregation capability inquiry message, an indication of a sidelink carrier aggregation capability of the first UE, wherein receiving the request to transmit the second set of one or more synchronization signals via the second component carrier is based at least in part on transmitting the indication of the sidelink carrier aggregation capability of the first UE.

11 . The apparatus of claim 8 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

transmit, to the network entity, the measurement report received from the first UE.

12 . The apparatus of claim 8 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

receive, from the second UE, a control message that indicates a completion of the sidelink connection between the first UE and the second UE in accordance with the sidelink carrier aggregation; and

transmit, to the network entity, the control message received from the second UE.

13 . The apparatus of claim 8 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

transmit, to the second UE and in accordance with a sidelink connection establishment procedure, a random access channel message based at least in part on a radio frequency band of the sidelink connection between the first UE and the second UE; and

receive, from the second UE, a random access channel response message based at least in part on transmitting the random access channel message.

14 . The apparatus of claim 8 , wherein establishing the sidelink connection between the first UE and the second UE is based at least in part on the first set of one or more synchronization signals or is based at least in part on both the first set of one or more synchronization signals and the second set of one or more synchronization signals.

15 . An apparatus for wireless communication at a network entity, comprising:

at least one processor; and

at least one memory coupled with the at least one processor, the at least one memory storing instructions executable by the at least one processor to cause the apparatus to:

receive, from a first user equipment (UE), a first measurement report indicative of one or more first measurements on a first set of one or more synchronization signals transmitted by a second UE via a first component carrier and a second measurement report indicative of one or more second measurements on a second set of one or more synchronization signals transmitted by the second UE via a second component carrier;

transmit a first control message associated with indirect communication between the first UE and the network entity via the second UE, wherein the first control message includes a set of parameters for activating sidelink carrier aggregation between the first UE and the second UE based at least in part on the one or more first measurements indicated by the first measurement report and the one or more second measurements indicated by the second measurement report, wherein the sidelink carrier aggregation is activated based at least in part on a switch from direct communication between the first UE and the network entity to the indirect communication between the first UE and the network entity; and

receive a second control message responsive to the first control message, wherein the second control message indicates a completion of a sidelink connection between the first UE and the second UE in accordance with the sidelink carrier aggregation.

16 . The apparatus of claim 15 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

transmit, to the second UE, a request to transmit the second set of one or more synchronization signals via the second component carrier, wherein receiving the second measurement report is based at least in part on transmitting the request.

17 . The apparatus of claim 16 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

transmit, to the second UE, a sidelink carrier aggregation capability inquiry message; and

receive, from the second UE in response to the sidelink carrier aggregation capability inquiry message, an indication of a sidelink carrier aggregation capability of the second UE, wherein transmitting the request to transmit the second set of one or more synchronization signals via the second component carrier is based at least in part on receiving the indication of the sidelink carrier aggregation capability of the second UE.

18 . The apparatus of claim 15 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

transmit, to the first UE, a request to measure the second set of one or more synchronization signals via the second component carrier and to transmit the second measurement report, wherein receiving the second measurement report is based at least in part on transmitting the request.

19 . The apparatus of claim 15 , wherein the first control message further includes a second set of parameters associated with the switch from the direct communication between the first UE and the network entity to the indirect communication between the first UE and the network entity via the second UE, and wherein transmitting the first control message is based at least in part on both the first measurement report and the second measurement report.

20 . The apparatus of claim 15 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

transmit, to the first UE, a third control message associated with the switch from the direct communication between the first UE and the network entity to the indirect communication between the first UE and the network entity via the second UE, wherein the third control message includes a second set of parameters associated with the switch.

21 . The apparatus of claim 20 , wherein the third control message is transmitted prior to the first control message, wherein transmitting the third control message is based at least in part on the first measurement report, and wherein transmitting the first control message is based at least in part on the second measurement report.

22 . The apparatus of claim 15 , wherein the instructions are further executable by the at least one processor to cause the apparatus to:

transmit data to, or receive data from, the second UE in accordance with the indirect communication between the first UE and the network entity via the second UE and the sidelink carrier aggregation between the first UE and the second UE.

23 . A method for wireless communication at a first user equipment (UE), comprising:

receiving, from a second UE, a first set of one or more synchronization signals via a first component carrier and a second set of one or more synchronization signals via a second component carrier;

transmitting a first measurement report indicative of one or more first measurements on the first set of one or more synchronization signals and a second measurement report indicative of one or more second measurements on the second set of one or more synchronization signals; and

receiving a control message associated with indirect communication between the first UE and a network entity via the second UE, wherein the control message includes a set of parameters for activating sidelink carrier aggregation between the first UE and the second UE based at least in part on the one or more first measurements indicated by the first measurement report and the one or more second measurements indicated by the second measurement report, wherein the sidelink carrier aggregation is activated based at least in part on a switch from direct communication between the first UE and the network entity to the indirect communication between the first UE and the network entity.

24 . The method of claim 23 , further comprising:

establishing a sidelink connection between the first UE and the second UE based at least in part on the control message, wherein the control message further includes a second set of parameters associated with the switch from the direct communication between the first UE and the network entity to the indirect communication between the first UE and the network entity via the second UE.

25 . The method of claim 23 , further comprising:

receiving a second control message associated with the switch from the direct communication between the first UE and the network entity to the indirect communication between the first UE and the network entity via the second UE, wherein the second control message includes a second set of parameters associated with the switch; and

establishing a sidelink connection between the first UE and the second UE based at least in part on the second control message.

26 . The method of claim 23 , further comprising:

receiving, from the network entity, a request to measure the second set of one or more synchronization signals via the second component carrier and to transmit the second measurement report, wherein receiving the second set of one or more synchronization signals and transmitting the second measurement report is based at least in part on receiving the request.

27 . The method of claim 23 , further comprising:

transmitting a second control message responsive to the control message, wherein the second control message indicates a completion of a sidelink connection between the first UE and the second UE and indicates the activation of the sidelink carrier aggregation for the sidelink connection.

28 . The method of claim 23 , further comprising:

receiving, from the second UE and in accordance with a sidelink connection establishment procedure, a random access channel message based at least in part on a radio frequency band of a sidelink connection between the first UE and the second UE; and

transmitting, to the second UE, a random access channel response message based at least in part on receiving the random access channel message.

29 . The method of claim 23 , further comprising:

transmitting data to, or receiving data from, the network entity via the second UE in accordance with the indirect communication between the first UE and the network entity via the second UE and the sidelink carrier aggregation between the first UE and the second UE.