Short Messages can be transmitted on PDCCH using P-RNTI with or without associated Paging message using Short Message field in DCI format 1_0 (see TS 38.212, clause 7.3.1.2.1).
Table 6.5-1 defines Short Messages. Bit 1 is the most significant bit.
If set to 1: indication of a BCCH modification other than SIB6, SIB7 and SIB8.
2
etwsAndCmasIndication
If set to 1: indication of an ETWS primary notification and/or an ETWS secondary notification and/or a CMAS notification.
3
stopPagingMonitoring
This bit can be used for only operation with shared spectrum channel access and if nrofPDCCH-MonitoringOccasionPerSSB-InPO is present.
If set to 1: indication that the UE may stop monitoring PDCCH occasion(s) for paging in this Paging Occasion as specified in TS 38.304, clause 7.1.
4
systemInfoModification-eDRX
If set to 1: indication of a BCCH modification other than SIB6, SIB7 and SIB8. This indication applies only to UEs using eDRX cycle longer than the BCCH modification period.
5 - 8
Not used in this release of the specification, and shall be ignored by UE if received.
The SCCH-Message class is the set of RRC messages that may be sent from the UE to the UE for unicast of NR sidelink communication on SCCH logical channel.
The MasterInformationBlockSidelink includes the system information transmitted by a UE via SL-BCH.
Signalling radio bearer:
N/A
RLC-SAP:
TM
Logical channel:
SBCCH
Direction:
UE to UE
MasterInformationBlockSidelink
MasterInformationBlockSidelink field descriptions
directFrameNumber
Indicates the frame number in which S-SSB transmitted.
inCoverage
Value true indicates that the UE transmitting the MasterInformationBlockSidelink is in network coverage, or UE selects GNSS timing as the synchronization reference source.
slotIndex
Indicates the slot index in which S-SSB transmitted.
The NotificationMessageSidelink message is used to send notification message from U2N Relay UE to the connected U2N Remote UE.
Signalling radio bearer:
The RemoteUEInformationSidelink message is used to request SIB(s) or provide paging related information as specified in clause 5.8.9.8.1.
Signalling radio bearer:
SL-SRB3
RLC-SAP:
AM
Logical channel:
SCCH
Direction:
L2 U2N Remote UE to L2 U2N Relay UE
RemoteUEInformationSidelink message
RemoteUEInformationSidelink-IEs field descriptions
sl-RequestedSIB-List
Contains a list of requested SIBs.
sl-PagingInfo-RemoteUE
Indicates the paging information used by L2 U2N Relay UE to perform the connected L2 U2N Remote UE's paging monitoring.
sl-PagingIdentityRemoteUE
Indicates the L2 U2N Remote UE's paging UE ID.
sl-PagingCycleRemoteUE
Indicates the L2 U2N Remote UE's UE specific DRX cycle as the minimum value of the one provided by upper layers (if configured) and the one provided by RRC layer (if configured). Value rf32 corresponds to 32 radio frames, value rf64 corresponds to 64 radio frames and so on.
The RRCReconfigurationSidelink message is the command to AS configuration of the PC5 RRC connection. It is only applied to unicast of NR sidelink communication.
Signalling radio bearer:
SL-SRB3
RLC-SAP:
AM
Logical channel:
SCCH
Direction:
UE to UE
RRCReconfigurationSidelink message
RRCReconfigurationSidelink field descriptions
sl-CSI-RS-FreqAllocation
Indicates the frequency domain position for sidelink CSI-RS.
sl-CSI-RS-FirstSymbol
Indicates the position of first symbol of sidelink CSI-RS.
sl-DRX-ConfigUC-PC5
Indicates the NR sidelink DRX configuration for unicast communication, as specified in TS 38.321
sl-LatencyBoundCSI-Report
Indicates the latency bound of SL CSI report from the associated SL CSI triggering in terms of number of slots.
sl-LatencyBoundIUC-Report
Indicates the latency bound of SL Inter-UE coordination report from the associated SL Inter-UE coordination explicit request triggering in terms of number of slots.
sl-LogicalChannelIdentity
Indicates the identity of the sidelink logical channel.
sl-MappedQoS-FlowsToAddList
Indicate the QoS flows to be mapped to the configured sidelink DRB. Each entry is indicated by the SL-PQFI, which is used between UEs, as defined in TS 23.287.
sl-MappedQoS-FlowsToReleaseList
Indicate the QoS flows to be released from the configured sidelink DRB. Each entry is indicated by the SL-PQFI, which is used between UEs, as defined in TS 23.287.
sl-MeasConfig
Indicates the sidelink measurement configuration for the unicast destination.
sl-OutOfOrderDelivery
Indicates whether or not outOfOrderDelivery specified in TS 38.323 is configured. This field should be either always present or always absent, after the sidelink radio bearer is established.
sl-PDCP-SN-Size
Indicates the PDCP SN size of the configured sidelink DRB.
sl-Resetconfig
Indicates that the full configuration should be applicable for the RRCReconfigurationSidelink message.
sl-SDAP-Header
Indicates whether or not a SDAP header is present on this sidelink DRB.
The RRCReconfigurationCompleteSidelink message is used to confirm the successful completion of a PC5 RRC AS reconfiguration. It is only applied to unicast of NR sidelink communication.
Signalling radio bearer:
SL-SRB3
RLC-SAP:
AM
Logical channel:
SCCH
Direction:
UE to UE
RRCReconfigurationCompleteSidelink message
RRCReconfigurationCompleteSidelink field descriptions
dummy
This field is not used in the specification. The UE shall not include this field. If received it shall be ignored by the peer UE.
sl-DRX-ConfigReject
Indicates the rejection of sidelink DRX configuration received from the peer UE for the corresponding NR sidelink unicast communication.
The RRCReconfigurationFailureSidelink message is used to indicate the failure of a PC5 RRC AS reconfiguration. It is only applied to unicast of NR sidelink communication.
Signalling radio bearer:
The UEAssistanceInformationSidelink message may include sidelink DRX assistance information used to determine the sidelink DRX configuration.
Signalling radio bearer:
SL-SRB3
RLC-SAP:
AM
Logical channel:
SCCH
Direction:
UE to UE
UEAssistanceInformationSidelink message
UEAssistanceInformationSidelink field descriptions
sl-PreferredDRX-ConfigList
Indicates a list of the reference sidelink DRX configurations provided by a UE to a peer UE for determining the sidelink DRX configuration.
The UECapabilityEnquirySidelink message is used to request UE sidelink capabilities. It is only applied to unicast of NR sidelink communication.
Signalling radio bearer:
SL-SRB3
RLC-SAP:
AM
Logical channel:
SCCH
Direction:
UE to UE
UECapabilityEnquirySidelink message
UECapabilityEnquirySidelink-IEs field descriptions
frequencyBandListFilterSidelink
This field is used to indicate frequency bands for which the peer UE is requested to provide supported bands and band combinations for NR sidelink communications. The UE always provides this field.
ue-CapabilityInformationSidelink
This field indicates the UECapabilityInformationSidelink message to provide the UE sidelink capability, which can be optionally sent together with UECapabilityEnquirySidelink.
The UECapabilityInformationSidelink message is used to transfer UE radio access capabilities. It is only applied to unicast of NR sidelink communication.
Signalling radio bearer: