On demand system information for sidelink communications

1. A method comprising:

receiving, by a wireless device from a base station, a first system information block (SIB) comprising a broadcast status parameter indicating that a second SIB for a sidelink communication is provided on-demand;

transmitting, based on the broadcast status parameter indicating that the second SIB is provided on-demand, a radio resource control (RRC) request to establish an RRC connection for the sidelink communication;

transmitting, based on the RRC connection, a sidelink request for a sidelink resource for the sidelink communication, wherein the sidelink request comprises a system information request for the second system information block; and

receiving an RRC message indicating the sidelink resource.

2. The method of claim 1 , wherein the sidelink request comprises

sidelink user equipment information.

3. The method of claim 1 , further comprising determining, based on the first system information block, to refrain from transmitting the system information request for the second system information block, wherein the transmitting the RRC request is based on the determining.

4. The method of claim 1 , wherein the transmitting the RRC request comprises transmitting the RRC request further based on one or more conditions to establish the RRC connection for the sidelink communication being met.

5. The method of claim 4 , further comprising determining to refrain from transmitting the system information request for the second system information block based on the one or more conditions being met.

6. The method of claim 5 , further comprising receiving the one or more conditions, wherein the one or more conditions comprise at least one of:

a service type of sidelink packets;

a quality of service (QoS) requirement of the sidelink packets;

a frequency of a cell on which the wireless device is camped;

an area of a cell on which the wireless device is camped; or

a timer for the one or more conditions is running.

7. The method of claim 1 , further comprising receiving, an RRC response comprising the second system information block, wherein the RRC response is:

an RRC setup message;

an RRC resume message;

an RRC reestablishment message; or

an RRC release message.

8. The method of claim 1 , wherein the RRC message comprises at least one of:

one or more sidelink resources;

one or more sidelink operation configurations;

one or more first validity conditions for the one or more sidelink resources; or

one or more second validity conditions for the one or more sidelink operation configurations.

9. The method of claim 1 , wherein:

the RRC message comprises one or more validity conditions for one or more sidelink resources, the one or more validity conditions comprising at least one of:

an area;

a frequency;

time value; or

one or more RRC states allowed to perform the sidelink communication; and

the method further comprises performing, based on the sidelink resource of the one or more sidelink resources and the one or more validity conditions of the sidelink resource being met, the sidelink communication.

10. The method of claim 1 , wherein:

the RRC message comprises one or more validity conditions for one or more sidelink operation configurations, the one or more validity conditions comprising at least one of:

a synchronization configuration;

a sensing configuration for a resource selection;

a zone configuration;

a configuration for a sidelink prioritization; or

a measurement and reporting configuration for a sidelink; and

the method further comprises performing, based on a sidelink operation configuration of the one or more sidelink operation configurations and the one or more validity conditions of the one or more sidelink operation configurations being met, the sidelink communication.

11. A wireless device comprising:

one or more processors; and

memory storing instructions that, when executed by the one or more processors, cause the wireless device to:

receive, from a base station, a first system information block (SIB) comprising a broadcast status parameter indicating that a second SIB for a sidelink communication is provided on-demand;

transmit, based on the broadcast status parameter indicating that the second SIB is provided on-demand, a radio resource control (RRC) request to establish an RRC connection for the sidelink communication;

transmit, based on the RRC connection, a sidelink request for a sidelink resource for the sidelink communication, wherein the sidelink request comprises a system information request for the second system information block; and

receive an RRC message indicating the sidelink resource.

12. The wireless device of claim 11 , wherein the sidelink request comprises

sidelink user equipment information.

13. The wireless device of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to determine, based on the first system information block, to refrain from transmitting the system information request for the second system information block, wherein the transmission of the RRC request is based on the determination.

14. The wireless device of claim 11 , wherein the transmission of the RRC request comprises transmitting the RRC request further based on one or more conditions to establish the RRC connection for the sidelink communication being met.

15. The wireless device of claim 14 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to determine to refrain from transmitting the system information request for the second system information block based on the one or more conditions being met.

16. The wireless device of claim 15 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to receive the one or more conditions, wherein the one or more conditions comprise at least one of:

a service type of sidelink packets;

a quality of service (QoS) requirement of the sidelink packets;

a frequency of a cell on which the wireless device is camped;

an area of a cell on which the wireless device is camped; or

a timer for the one or more conditions is running.

17. The wireless device of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the wireless device to receive, an RRC response comprising the second system information block, wherein the RRC response is:

an RRC setup message;

an RRC resume message;

an RRC reestablishment message; or

an RRC release message.

18. The wireless device of claim 11 , wherein the RRC message comprises at least one of:

one or more sidelink resources;

one or more sidelink operation configurations;

one or more first validity conditions for the one or more sidelink resources; or

one or more second validity conditions for the one or more sidelink operation configurations.

19. The wireless device of claim 11 , wherein:

the RRC message comprises one or more validity conditions for one or more sidelink resources, the one or more validity conditions comprising at least one of:

an area;

a frequency;

time value; or

one or more RRC states allowed to perform the sidelink communication; and

wherein the instructions, when executed by the one or more processors, further cause the wireless device to perform, based on the sidelink resource of the one or more sidelink resources and the one or more validity conditions of the sidelink resource being met, the sidelink communication.

20. A system comprising:

a base station comprising:

one or more first processors; and

first memory storing first instructions that, when executed by the one or more first processors, cause the base station to transmit a first system information block (SIB) comprising a broadcast status parameter indicating that a second SIB for a sidelink communication is provided on-demand; and

a wireless device comprising:

one or more second processors; and

second memory storing second instructions that, when executed by the one or more second processors, cause the wireless device to:

receive the first system information block;

transmit, based on the broadcast status parameter indicating that the second SIB is provided on-demand, a radio resource control (RRC) request to establish an RRC connection for the sidelink communication;

transmit, based on the RRC connection, a sidelink request for a sidelink resource for the sidelink communication, wherein the sidelink request comprises a system information request for the second system information block; and

receive an RRC message indicating the sidelink resource.