System information block and paging transmission priority for sidelink relaying

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

a processor, memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

receive, from a base station, a system information block, a paging message, or both, wherein a signaling radio bearer (SRB) is configured for the system information block, the paging message, or both;

determine a priority level associated with relaying the system information block, the paging message, or both on a sidelink channel, wherein the priority level is for the SRB configured for system information, paging messages, or both, wherein a second

priority level is for a second SRB that is configured for unicast radio resource control messages communicated over an interface between the first UE and a second UE, and wherein a third priority level is for a third SRB that is configured for non-access stratum messages or other types of radio resource control messages; and

transmit, to the second UE on the sidelink channel, the system information block, the paging message, or both based at least in part on the priority level,

the second priority level, and the third priority level.

2 . The apparatus of claim 1 , wherein the priority level

for the SRB is higher than the second priority level for the second SRB and lower than the third priority level for the third SRB.

3 . The apparatus of claim 2 , wherein the second SRB is sidelink SRB3 and the third SRB is sidelink SRB0, sidelink SRB1, or sidelink SRB2.

4 . The apparatus of claim 1 , wherein the instructions are further

executable by the processor to cause the apparatus to:

receive an indication of the priority level for the SRB in a radio resource control message.

5 . The apparatus of claim 1 , wherein the instructions are further

executable by the processor to cause the apparatus to:

transmit, to the second UE on the sidelink channel, a sidelink control information message indicating a set of one or more resources for the second UE to receive a message

comprising the system information block, the paging message, or both, wherein the sidelink

control information message comprises a field indicating that the message corresponds to system

information, paging information, or both.

6 . The apparatus of claim 1 , wherein the instructions are further

executable by the processor to cause the apparatus to:

determine a defined set of one or more transmission occasions for relaying the system information block, the paging message, or both on the sidelink channel; and

select a transmission occasion of the defined set of one or more transmission occasions, wherein the system information block, the paging message, or both are transmitted in

the selected transmission occasion.

7 . The apparatus of claim 1 , wherein the instructions are further

executable by the processor to cause the apparatus to:

perform a channel access procedure for the sidelink channel, wherein the system

information block, the paging message, or both are transmitted based at least in part on the

channel access procedure.

8 . The apparatus of claim 7 , wherein the instructions to perform the

channel access procedure are executable by the processor to cause the apparatus to:

sense the sidelink channel for a time duration; and

reserve a set of one or more resources on the sidelink channel based at least in part on the sensing and the priority level, wherein the system information block, the paging

message, or both are transmitted in the reserved set of one or more resources.

9 . The apparatus of claim 1 , wherein the instructions are

further executable by the processor to cause the apparatus to:

determine a scheduled communication on a second channel at least partially overlapping in time with the transmitting the system information block, the paging message, or

both; and

determine a power scaling value based at least in part on the priority level and a priority level for the second channel, wherein the system information block, the paging message, or both are transmitted based at least in part on the power scaling value.

10 . The apparatus of claim 1 , wherein the instructions are

further executable by the processor to cause the apparatus to:

determine a scheduled communication on a second channel at least partially overlapping in time with the transmitting the system information block, the paging message, or

both;

compare the priority level to a priority level for the second channel; and

refrain from communicating the scheduled communication on the second channel based at least in part on the comparing.

11 . The apparatus of claim 1 , wherein the instructions are

further executable by the processor to cause the apparatus to:

select a first set of one or more resources for transmitting the system information block, the paging message, or both;

determine a scheduled communication on a second channel at least partially overlapping in time with the first set of one or more resources;

compare the priority level to a priority level for the second channel; and

refrain from transmitting the system information block, the paging message, or

both in the first set of one or more resources based at least in part on the comparing, wherein the

system information block, the paging message, or both are transmitted in a second set of one or

more resources based at least in part on the comparing.

12 . The apparatus of claim 1 , wherein the instructions are further

executable by the processor to cause the apparatus to:

receive, from the base station, a radio resource control message configuring the priority level associated with relaying the system information block, the paging message, or both

on the sidelink channel.

13 . The apparatus of claim 1 , wherein the priority level comprises a lowest transmission priority or a highest transmission priority.

14 . The apparatus of claim 1 , wherein the priority level comprises a

first priority index value, and the instructions are further executable by the processor to cause the

apparatus to:

compare the first priority index value to at least a second priority index value for a second channel, wherein the system information block, the paging message, or both are transmitted based at least in part on the comparing.

15 . The apparatus of claim 1 , wherein the system information block,

the paging message, or both comprises the paging message and the instructions to determine the

priority level are executable by the processor to cause the apparatus to:

determine the priority level based at least in part on whether the paging message is for a common system information block, a dedicated system information block, dedicated data,

or a combination thereof.

16 . The apparatus of claim 15 , wherein the paging message is for dedicated data, and wherein the priority level is set to a priority level of the dedicated data.

17 . The apparatus of claim 1 , wherein the system information block,

the paging message, or both comprises the system information block and the instructions to

determine the priority level are executable by the processor to cause the apparatus to:

determine the priority level based at least in part on a broadcast status of the system information block, whether the system information block comprises a cell-specific update

or an area-specific update, a type of the system information block, whether the system information block is periodic or on-demand, or a combination thereof.

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

a processor;

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

determine a priority level associated with relaying a system information block, a paging message, or both on a sidelink channel;

determine a set of one or more resources for receiving the system information block, the paging message, or both based at least in part on the priority level;

receive, from a second UE on the sidelink channel, the system information block, the paging message, or both in the determined set of one or more resources;

determine a scheduled communication on a second channel at least partially overlapping in time with the set of one or more resources; and

determine a power scaling value based at least in part on the priority level and a second priority level for the second channel, wherein the system information block,

the paging message, or both are received based at least in part on the power scaling value.

19 . The apparatus of claim 18 , wherein the instructions are further

executable by the processor to cause the apparatus to:

receive, from the second UE on the sidelink channel, a sidelink control information message indicating the set of one or more resources for receiving a message

comprising the system information block, the paging message, or both, wherein the sidelink

control information message comprises a field indicating that the message corresponds to system

information, paging information, or both.

20 . The apparatus of claim 18 , wherein the instructions are further

executable by the processor to cause the apparatus to:

determine a defined set of one or more transmission occasions for receiving the system information block, the paging message, or both on the sidelink channel, wherein the

defined set of one or more transmission occasions comprises the set of one or more resources;

perform a wake up procedure prior to the set of one or more resources; and

monitor the set of one or more resources for the system information block, the paging message, or both based at least in part on the defined set of one or more transmission

occasions.

21 . The apparatus of claim 18 , wherein the instructions are

further executable by the processor to cause the apparatus to:

schedule a communication on the second channel at least partially

overlapping in time with the set of one or more resources;

compare the priority level to the second priority level for the second channel; and

refrain from communicating the scheduled communication on the second channel based at least in part on the comparing.

22 . An apparatus for wireless communications at a base

station, comprising:

a processor;

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

determine a priority level associated with relaying a system information

block, a paging message, or both on a sidelink channel, wherein the priority level is for a signaling radio bearer (SRB) configured for system information, paging messages, or both, wherein determining the priority level for the SRB is based at least in part on:

a second priority level for a second SRB that is configured for

unicast radio resource control messages communicated over an interface between the first UE and a second UE and

a third priority level for a third SRB that is configured for non-access stratum messages or other types of radio resource control messages;

transmit, to a user equipment (UE), a message configuring the UE with the priority level; and

transmit, to the UE, the system information block, the paging message, or both.

23 . The apparatus of claim 22 , wherein the priority

level for the SRB is higher than the second priority level for] the second SRB and lower than the third priority level for the third SRB.

24 . The apparatus of claim 22 , wherein the message comprises a radio

resource control message comprising a field indicating the priority level.

25 . The apparatus of claim 22 , wherein the instructions are further

executable by the processor to cause the apparatus to:

transmit, to the UE, a radio resource control message configuring a defined set of one or more transmission occasions for the UE to relay the system information block, the paging

message, or both on the sidelink channel.

26 . A method for wireless communications at a first user

equipment (UE), comprising

receiving, from a base station, a system information block, a paging message, or both, wherein a signaling radio bearer (SRB) is configured for the system information block, the

paging message, or both;

determining a priority level associated with relaying the system information block, the paging message, or both on a sidelink channel, wherein the priority level is for the

SRB configured for system information, paging messages, or both, wherein a second priority

level is for a second SRB that is configured for unicast radio resource control messages communicated over an interface between the first UE and a second UE, and wherein a third

priority level is for a third SRB that is configured for non-access stratum messages or other types

of radio resource control messages; and

transmitting, to the second UE on the sidelink channel, the system

information block, the paging message, or both based at least in part on the priority level, the

second priority level, and the third priority level.