Content for TS 38.331 Word version: 17.6.0

1… 4… 5… 5.2.2.4… 5.3… 5.3.3… 5.3.5… 5.3.5.5… 5.3.5.6… 5.3.5.7… 5.3.5.13… 5.3.6… 5.3.8… 5.3.13… 5.3.14… 5.4… 5.5… 5.5.3… 5.5.4… 5.5.5… 5.5a… 5.7… 5.7.4… 5.7.8… 5.8… 5.8.9… 5.8.10… 5.8.11… 5.9… 6… 6.2.2… 6-2-2-25… 6.3… 6.3.2… 6-3-2-27… 6-3-2-49… 6-3-2-73… 6-3-2-95… 6-3-2-108… 6-3-2-134… 6-3-2-162… 6-3-2-188… 6-3-2-213… 6-3-2-243… 6-3-2-271… 6-3-2-297… 6.3.3… 6-3-3-25… 6-3-3-51… 6.3.4… 6.3.5… 6-3-5-25… 6.3.6… 6.4… 7… 9… 11… A… A.4… B…

9.1 Specified configurations 9.1.1 Logical channel configurations 9.1.1.1 BCCH configuration 9.1.1.2 CCCH configuration 9.1.1.3 PCCH configuration 9.1.1.4 SCCH configuration 9.1.1.5 STCH configuration 9.1.1.6 MCCH configuration 9.1.1.7 MTCH configuration for MBS broadcast 9.2 Default radio configurations 9.2.1 Default SRB configurations 9.2.2 Default MAC Cell Group configuration 9.2.3 Default values timers and constants 9.2.4 Default PC5 Relay RLC Channel 9.2.5 Default SRAP configurations 9.3 Sidelink pre-configured parameters — NR-Sidelink-Preconf — SL-PreconfigurationNR — End of NR-Sidelink-Preconf 9.4 Radio Information Related to Discovery Message — SL-AccessInfo-L2U2N 10.1 General 10.2 ASN.1 violation or encoding error 10.3 Field set to a not comprehended value 10.4 Mandatory field missing 10.5 Not comprehended field
...

9 Specified and default radio configurations p. 1212

Specified and default configurations are configurations of which the details are specified in the standard. Specified configurations are fixed while default configurations can be modified using dedicated signalling. The default value for the parameters not listed in following clauses shall be set such as the corresponding features are not configured, i.e. release or false unless explicitly stated otherwise.

9.1 Specified configurations p. 1212

9.1.1 Logical channel configurations p. 1212

9.1.1.1 BCCH configuration p. 1212

Parameters

Name	Value	Semantics description	Ver
SDAP configuration	Not used
PDCP configuration	Not used
RLC configuration	TM
Logical channel configuration	Not used

9.1.1.2 CCCH configuration p. 1213

Parameters

Name	Value	Semantics description
SDAP configuration	Not used
PDCP configuration	Not used
RLC configuration	TM
Logical channel configuration
>priority	1	Highest priority
>prioritisedBitRate	infinity
>bucketSizeDuration	ms1000
>logicalChannelGroup	0

9.1.1.3 PCCH configuration p. 1213

Parameters

Name	Value	Semantics description	Ver
SDAP configuration	Not used
PDCP configuration	Not used
RLC configuration	TM
Logical channel configuration	Not used

9.1.1.4 SCCH configuration p. 1213

Parameters that are specified for unicast of NR sidelink communication, which is used for the sidelink signalling radio bearer of PC5-RRC message. The SL-SRB using this SCCH configuration is named as SL-SRB3.

Name	Value	Semantics description
PDCP configuration
>t-Reordering	Undefined	Selected by the receiving UE, up to UE implementation
>pdcp-SN-Size	12
RLC configuration		AM RLC
>sn-FieldLength	12
>t-Reassembly	Undefined	Selected by the receiving UE, up to UE implementation
>t-PollRetransmit	Undefined	Selected by the transmitting UE, up to UE implementation
>pollPDU	Undefined	Selected by the transmitting UE, up to UE implementation
>pollByte	Undefined	Selected by the transmitting UE, up to UE implementation
>maxRetxThreshold	Undefined	Selected by the transmitting UE, up to UE implementation
>t-StatusProhibit	Undefined	Selected by the receiving UE, up to UE implementation
>logicalChannelIdentity	3
MAC configuration
>priority	1
>prioritisedBitRate	infinity
>logicalChannelGroup	0
>schedulingRequestId	0	The scheduling request configuration with this value is applicable for this SCCH if configured by the network.
>sl-HARQ-FeedbackEnabled	Undefined	Selected by the transmitting UE, up to UE implementation

Parameters that are specified of NR sidelink communication, which is used for the sidelink signalling radio bearer of unprotected PC5-S message (e.g. Direct Link Establishment Request, TS 24.587 or Prose Direct Link Establishment Request, TS 24.554). The SL-SRB using this SCCH configuration is named as SL-SRB0.

Name	Value	Semantics description
PDCP configuration
>t-Reordering	Undefined	Selected by the receiving UE, up to UE implementation
>pdcp-SN-Size	12
RLC configuration		UM RLC
>sn-FieldLength	6
>t-Reassembly	Undefined	Selected by the receiving UE, up to UE implementation
>logicalChannelIdentity	0
MAC configuration
>priority	1
>prioritisedBitRate	infinity
>logicalChannelGroup	0
>schedulingRequestId	0	The scheduling request configuration with this value is applicable for this SCCH if configured by the network.
>sl-HARQ-FeedbackEnabled	Undefined	Selected by the transmitting UE, up to UE implementation

Parameters that are specified for unicast of NR sidelink communication, which is used for the sidelink signalling radio bearer of PC5-S message establishing PC5-S security (e.g. Direct Link Security Mode Command and Direct Link Security Mode Complete, TS 24.587 or ProSe Direct Link Security Mode Command and ProSe Direct Link Security Mode Complete, TS 24.554). The SL-SRB using this SCCH configuration is named as SL-SRB1.

Name	Value	Semantics description
PDCP configuration
>t-Reordering	Undefined	Selected by the receiving UE, up to UE implementation
>pdcp-SN-Size	12
RLC configuration		AM RLC
>sn-FieldLength	12
>t-Reassembly	Undefined	Selected by the receiving UE, up to UE implementation
>t-PollRetransmit	Undefined	Selected by the transmitting UE, up to UE implementation
>pollPDU	Undefined	Selected by the transmitting UE, up to UE implementation
>pollByte	Undefined	Selected by the transmitting UE, up to UE implementation
>maxRetxThreshold	Undefined	Selected by the transmitting UE, up to UE implementation
>t-StatusProhibit	Undefined	Selected by the receiving UE, up to UE implementation
>logicalChannelIdentity	1
MAC configuration
>priority	1
>prioritisedBitRate	infinity
>logicalChannelGroup	0
>schedulingRequestId	0	The scheduling request configuration with this value is applicable for this SCCH if configured by the network.
>sl-HARQ-FeedbackEnabled	Undefined	Selected by the transmitting UE, up to UE implementation

Parameters that are specified for unicast of NR sidelink communication, which is used for the sidelink signalling radio bearer of protected PC5-S message except Direct Link Security Mode Complete, TS 24.587 or Prose Direct Link Security Mode Complete, TS 24.554. The SL-SRB using this SCCH configuration is named as SL-SRB2.

Name	Value	Semantics description
PDCP configuration
>t-Reordering	Undefined	Selected by the receiving UE, up to UE implementation
>pdcp-SN-Size	12
RLC configuration		AM RLC
>sn-FieldLength	12
>t-Reassembly	Undefined	Selected by the receiving UE, up to UE implementation
>t-PollRetransmit	Undefined	Selected by the transmitting UE, up to UE implementation
>pollPDU	Undefined	Selected by the transmitting UE, up to UE implementation
>pollByte	Undefined	Selected by the transmitting UE, up to UE implementation
>maxRetxThreshold	Undefined	Selected by the transmitting UE, up to UE implementation
>t-StatusProhibit	Undefined	Selected by the receiving UE, up to UE implementation
>logicalChannelIdentity	2
MAC configuration
>priority	1
>prioritisedBitRate	infinity
>logicalChannelGroup	0
>schedulingRequestId	0	The scheduling request configuration with this value is applicable for this SCCH if configured by the network.
>sl-HARQ-FeedbackEnabled	Undefined	Selected by the transmitting UE, up to UE implementation

Parameters that are specified for NR sidelink discovery, which is used for the sidelink signalling radio bearer of NR sidelink discovery messages (e.g., Announcement message, Solicitation message and Response message, see TS 23.304). The SL-SRB using this SCCH configuration is named as SL-SRB4.

Name	Value	Semantics description
PDCP configuration
>t-Reordering	Undefined	Selected by the receiving UE, up to UE implementation
>pdcp-SN-Size	12
RLC configuration		UM RLC
>sn-FieldLength	6
>t-Reassembly	Undefined	Selected by the receiving UE, up to UE implementation
>logicalChannelIdentity	58
MAC configuration
>priority	1
>prioritisedBitRate	infinity
>logicalChannelGroup	0
>schedulingRequestId	0	The scheduling request configuration with this value is applicable for this SCCH if configured by the network.
>sl-HARQ-FeedbackEnabled	disabled	HARQ feedback is not supported for NR sidelink discovery transmission

Parameters that are specified for NR sidelink L2 U2N Relay operations, which is used for the PC5 Relay RLC channel for Remote UE's SRB0 message transmission/reception. The PC5 Relay RLC channel using this configuration is named as SL-RLC0.

Name	Value	Semantics description
RLC configuration		AM
>sn-FieldLength	12
>t-Reassembly	Undefined	Selected by the receving UE, up to UE implementation
>t-PollRetransmit	Undefined	Selected by the transmitting UE, up to UE implementation
>pollPDU	Undefined	Selected by the transmitting UE, up to UE implementation
>pollByte	Undefined	Selected by the transmitting UE, up to UE implementation
>maxRetxThreshold	Undefined	Selected by the transmitting UE, up to UE implementation
>t-StatusProhibit	Undefined	Selected by the receiving UE, up to UE implementation
>logicalChannelIdentity	56
MAC configuration
>priority	1
>proritisedBitRate	Inifinity
>logicalChannelGroup	0
>schedulingRequestId	0	The scheduling request configuration with this value is applicable for this SCCH if configured by the network. The scheduling request configuration is not applicable to L2 U2N Remote UE.
>sl-HARQ-FeedbackEnabled	Undefined	Selected by the transmitting UE, up to UE implementation

9.1.1.5 STCH configuration p. 1216

Parameters that are specified for NR sidelink communication, which is used for the sidelink data radio bearer.

Name	Value	Semantics description
PDCP configuration
>t-Reordering	Undefined	Selected by the receiving UE, up to UE implementation
>pdcp-SN-Size	12	For broadcast and groupcast of NR sidelink communication
>maxCID	15	For broadcast and groupcast of NR sidelink communication
>profiles
RLC configuration		For broadcast and groupcast of NR sidelink communication, uni-directional UM RLC UM window size is set to 32
>t-Reassembly	Undefined	Selected by the receiving UE, up to Up to UE implementation
>sn-FieldLength	6	For broadcast and groupcast of NR sidelink communication
>logicalChannelIdentity	Undefined	Selected by the transmitting UE, up to UE implementation
MAC configuration
>priority

9.1.1.6 MCCH configuration p. 1216

Parameters that are specified for MCCH.

Name	Value	Semantics description
RLC configuration		UM RLC
>sn-FieldLength	6
>t-Reassembly	ms0

9.1.1.7 MTCH configuration for MBS broadcast p. 1217

Parameters that are specified for MBS broadcast MTCH.

Name	Value	Semantics description
PDCP configuration
>t-Reordering	ms0
>pdcp-SN-SizeDL	18
RLC configuration		UM RLC
>sn-FieldLength	12
>t-Reassembly	ms0

9.1.2 Void

9.2 Default radio configurations p. 1217

The following clauses only list default values for REL-15 parameters included in protocol version v15.3.0. For all fields introduced in a later protocol version, the default value is "released" or "false" unless explicitly specified otherwise. If the UE is to apply default configuration while it is configured with some critically extended fields, the UE shall apply the original version of those fields with only default values.

9.2.1 Default SRB configurations p. 1217

Parameters

Name	Value			Semantics description	Ver
Name	SRB1	SRB2	SRB3	Semantics description	Ver
PDCP-Config
>t-Reordering	infinity
RLC-Config CHOICE	Am
ul-AM-RLC
>sn-FieldLength	size12
>t-PollRetransmit	ms45
>pollPDU	infinity
>pollByte	infinity
>maxRetxThreshold	t8
dl-AM-RLC
>sn-FieldLength	size12
>t-Reassembly	ms35
>t-StatusProhibit	ms0
logicalChannelIdentity	1	2	3
LogicalChannelConfig
>priority	1	3	1
>prioritisedBitRate	infinity
>logicalChannelGroup	0

9.2.2 Default MAC Cell Group configuration p. 1217

Parameters

Name	Value	Semantics description	Ver
MAC Cell Group configuration
bsr-Config
>periodicBSR-Timer	sf10
>retxBSR-Timer	sf80
phr-Config
>phr-PeriodicTimer	sf10
>phr-ProhibitTimer	sf10
>phr-Tx-PowerFactorChange	dB1

9.2.3 Default values timers and constants p. 1218

Parameters

Name	Value	Semantics description	Ver
t310	ms1000
n310	n1
t311	ms30000
n311	n1

9.2.4 Default PC5 Relay RLC Channel p. 1218

Parameters of the PC5 Relay RLC Channel used for Remote UE's SRB1 RRC message transmission and reception. The PC5 Relay RLC Channel using this configuration is named as SL-RLC1.

Name	Value	Semantics description
RLC configuration		AM
>sn-FieldLength	12
>t-Reassembly	Undefined	Selected by the receving UE, up to UE implementation
>t-PollRetransmit	Undefined	Selected by the transmitting UE, up to UE implementation
>pollPDU	Undefined	Selected by the transmitting UE, up to UE implementation
>pollByte	Undefined	Selected by the transmitting UE, up to UE implementation
>maxRetxThreshold	Undefined	Selected by the transmitting UE, up to UE implementation
>t-StatusProhibit	Undefined	Selected by the receiving UE, up to UE implementation
>logicalChannelIdentity	57
MAC configuration
>priority	1
>proritisedBitRate	Inifinity
>logicalChannelGroup	0
>schedulingRequestId	0	The scheduling request configuration with this value is applicable for this SCCH if configured by the network.

9.2.5 Default SRAP configurations p. 1218

Parameters that are used for reception of Remote UE's RRCResume, RRCRelease in response to an RRCResumeRequest and RRCReestablishment messages.

Name	Value	Semantics description
SL SRAP Config
> sl-LocalIdentity	Undefined	SRAP PDUs with any local Identity will be submitted to the SRB1 PDCP entity.
> sl-RemoteUE-RB-Identity	SRB1

9.3 Sidelink pre-configured parameters p. 1219

This ASN.1 segment is the start of the NR definitions of pre-configured sidelink parameters.

– NR-Sidelink-Preconf p. 1219

-- ASN1START
-- TAG-NR-SIDELINK-PRECONF-DEFINITIONS-START
NR-Sidelink-Preconf DEFINITIONS AUTOMATIC TAGS ::=
BEGIN
IMPORTS
    SL-RemoteUE-Config-r17,
    SL-DRX-ConfigGC-BC-r17,
    SL-FreqConfigCommon-r16,
    SL-RadioBearerConfig-r16,
    SL-RLC-BearerConfig-r16,
    SL-EUTRA-AnchorCarrierFreqList-r16,
    SL-NR-AnchorCarrierFreqList-r16,
    SL-MeasConfigCommon-r16,
    SL-UE-SelectedConfig-r16,
    TDD-UL-DL-ConfigCommon,
    maxNrofFreqSL-r16,
    maxNrofSLRB-r16,
    maxSL-LCID-r16
FROM NR-RRC-Definitions;
-- TAG-NR-SIDELINK-PRECONF-DEFINITIONS-STOP
-- ASN1STOP

– SL-PreconfigurationNR p. 1219

The IE SL-PreconfigurationNR includes the sidelink pre-configured parameters used for NR sidelink communication. Need codes or conditions specified for subfields in SL-PreconfigurationNR do not apply.

SL-PreconfigurationNR information elements

-- ASN1START
-- TAG-SL-PRECONFIGURATIONNR-START
SL-PreconfigurationNR-r16 ::= SEQUENCE {
    sidelinkPreconfigNR-r16 SidelinkPreconfigNR-r16,
    ...
}
SidelinkPreconfigNR-r16 ::= SEQUENCE {
  sl-PreconfigFreqInfoList-r16
     SEQUENCE (SIZE (1..maxNrofFreqSL-r16)) OF SL-FreqConfigCommon-r16
     OPTIONAL,
  sl-PreconfigNR-AnchorCarrierFreqList-r16
     SL-NR-AnchorCarrierFreqList-r16
     OPTIONAL,
  sl-PreconfigEUTRA-AnchorCarrierFreqList-r16
     SL-EUTRA-AnchorCarrierFreqList-r16
     OPTIONAL,
  sl-RadioBearerPreConfigList-r16
     SEQUENCE (SIZE (1..maxNrofSLRB-r16)) OF SL-RadioBearerConfig-r16
     OPTIONAL,
  sl-RLC-BearerPreConfigList-r16
     SEQUENCE (SIZE (1..maxSL-LCID-r16)) OF SL-RLC-BearerConfig-r16
     OPTIONAL,
  sl-MeasPreConfig-r16
     SL-MeasConfigCommon-r16
     OPTIONAL,
  sl-OffsetDFN-r16
     INTEGER (1..1000)
     OPTIONAL,
  t400-r16
     ENUMERATED{ms100, ms200, ms300, ms400, ms600, ms1000, ms1500, ms2000}
     OPTIONAL,
  sl-MaxNumConsecutiveDTX-r16
     ENUMERATED {n1, n2, n3, n4, n6, n8, n16, n32}
     OPTIONAL,
  sl-SSB-PriorityNR-r16
     INTEGER (1..8)
     OPTIONAL,
  sl-PreconfigGeneral-r16
     SL-PreconfigGeneral-r16
     OPTIONAL,
  sl-UE-SelectedPreConfig-r16
     SL-UE-SelectedConfig-r16
     OPTIONAL,
  sl-CSI-Acquisition-r16
     ENUMERATED {enabled}
     OPTIONAL,
  sl-RoHC-Profiles-r16
     SL-RoHC-Profiles-r16
     OPTIONAL,
  sl-MaxCID-r16
     INTEGER (1..16383)
     DEFAULT 15,
  ...,
  [[
  sl-DRX-PreConfigGC-BC-r17
     SL-DRX-ConfigGC-BC-r17
     OPTIONAL,
  sl-TxProfileList-r17
     SL-TxProfileList-r17
     OPTIONAL,
  sl-PreconfigDiscConfig-r17
     SL-RemoteUE-Config-r17
     OPTIONAL
  ]]
}
SL-TxProfileList-r17 ::= SEQUENCE (SIZE (1..256)) OF SL-TxProfile-r17
SL-TxProfile-r17 ::= ENUMERATED
 {drx-Compatible, drx-Incompatible, spare6, spare5, spare4, spare3,spare2, spare1}
SL-PreconfigGeneral-r16 ::= SEQUENCE {
  sl-TDD-Configuration-r16
    TDD-UL-DL-ConfigCommon 
     OPTIONAL,
  reservedBits-r16
     BIT STRING (SIZE (2))
     OPTIONAL,
    ...
}
SL-RoHC-Profiles-r16 ::= SEQUENCE {
    profile0x0001-r16  BOOLEAN,
    profile0x0002-r16  BOOLEAN,
    profile0x0003-r16  BOOLEAN,
    profile0x0004-r16  BOOLEAN,
    profile0x0006-r16  BOOLEAN,
    profile0x0101-r16  BOOLEAN,
    profile0x0102-r16  BOOLEAN,
    profile0x0103-r16  BOOLEAN,
    profile0x0104-r16  BOOLEAN
}
-- TAG-SL-PRECONFIGURATIONNR-STOP
-- ASN1STOP

SL-PreconfigurationNR field descriptions
sl-DRX-PreConfig-GC-BC This field indicates the sidelink DRX configuration for groupcast and broadcast communication, as specified in TS 38.321.
sl-OffsetDFN Indicates the timing offset for the UE to determine DFN timing when GNSS is used for timing reference. Value 1 corresponds to 0.001 milliseconds, value 2 corresponds to 0.002 milliseconds, and so on. If the field is absent, no offset is applied.
sl-PreconfigDiscConfig This field indicates the configuration for discovery message transmission used by NR sidelink U2N Remote UE.
sl-PreconfigEUTRA-AnchorCarrierFreqList This field indicates the EUTRA anchor carrier frequency list, which can provide the NR sidelink communication configuration.
sl-PreconfigFreqInfoList This field indicates the NR sidelink communication and/ or NR sidelink discovery configuration some carrier frequency(ies). In this release, only one SL-FreqConfig can be configured in the list.
sl-PreconfigNR-AnchorCarrierFreqList This field indicates the NR anchor carrier frequency list, which can provide the NR sidelink communication configuration.
sl-RadioBearerPreConfigList This field indicates one or multiple sidelink radio bearer configurations.
sl-RLC-BearerPreConfigList This field indicates one or multiple sidelink RLC bearer configurations.
sl-RoHC-Profiles This field indicates the supported RoHC profiles for NR sidelink communications.
sl-SSB-PriorityNR This field indicates the priority of NR sidelink SSB transmission and reception.
sl-TxProfileList List of one or multiple Tx profiles, indicating the compatibility of supporting SL DRX as specified in TS 38.321. It is up to the UE implementation whether/how to apply this field.

– End of NR-Sidelink-Preconf p. 1221

-- ASN1START
END
-- ASN1STOP

9.4 Radio Information Related to Discovery Message p. 1216

This clause specifies RRC information elements that are transferred in Discovery Message.

– SL-AccessInfo-L2U2N p. 1221

The IE SL-AccessInfo-L2U2N includes the radio information included in Discovery Message used for L2 U2N relay operation.

SL-AccessInfo-L2U2N information elements

-- ASN1START
-- TAG-SL-ACCESSINFO-L2U2N-START
NR-Sidelink-DiscoveryMessage DEFINITIONS AUTOMATIC TAGS ::=
BEGIN
IMPORTS
    CellAccessRelatedInfo,
    SL-ServingCellInfo-r17
FROM NR-RRC-Definitions;
SL-AccessInfo-L2U2N-r17 ::= SEQUENCE {
    cellAccessRelatedInfo-r17  CellAccessRelatedInfo,
    sl-ServingCellInfo-r17     SL-ServingCellInfo-r17,
    ...
}
END
-- TAG-SL-ACCESSINFO-L2U2N-STOP
-- ASN1STOP

10 Generic error handling p. 1223

10.1 General p. 1223

The generic error handling defined in the subsequent clauses applies unless explicitly specified otherwise e.g. within the procedure specific error handling.

The UE shall consider a value as not comprehended when it is set:

to an extended value that is not defined in the version of the transfer syntax supported by the UE;
to a spare or reserved value unless the specification defines specific behaviour that the UE shall apply upon receiving the concerned spare/reserved value.

The UE shall consider a field as not comprehended when it is defined:

as spare or reserved unless the specification defines specific behaviour that the UE shall apply upon receiving the concerned spare/reserved field.

10.2 ASN.1 violation or encoding error p. 1223

The UE shall:

1 >

when receiving an RRC message on the BCCH, CCCH, PCCH, MCCH or a PC5 RRC message on SBCCH for which the abstract syntax is invalid [6]:

2 >

ignore the message.

10.3 Field set to a not comprehended value p. 1223

The UE shall, when receiving an RRC message or PC5 RRC message on any logical channel:

1 >

if the message includes a field that has a value that the UE does not comprehend:

2 >

if a default value is defined for this field:

3 >

treat the message while using the default value defined for this field;

2 >

else if the concerned field is optional:

3 >

treat the message as if the field were absent and in accordance with the need code for absence of the concerned field;

2 >

else:

3 >

treat the message as if the field were absent and in accordance with clause 10.4.

10.4 Mandatory field missing p. 1223

The UE shall:

1 >

if the message includes a field that is mandatory to include in the message (e.g. because conditions for mandatory presence are fulfilled) and that field is absent or treated as absent:

2 >

if the RRC message was not received on DCCH or CCCH; or

2 >

if the PC5 RRC message was not received on SCCH:

3 >

if the field concerns a (sub-field of) an entry of a list (i.e. a SEQUENCE OF):

4 >

treat the list as if the entry including the missing or not comprehended field was absent;

3 >

else if the field concerns a sub-field of another field, referred to as the 'parent' field i.e. the field that is one nesting level up compared to the erroneous field:

4 >

consider the 'parent' field to be set to a not comprehended value;

4 >

apply the generic error handling to the subsequent 'parent' field(s), until reaching the top nesting level i.e. the message level;

3 >

else (field at message level):

4 >

ignore the message.

The following ASN.1 further clarifies the levels applicable in case of nested error handling for errors in extension fields.

-- /example/ ASN1START
-- Example with extension addition group
ItemInfoList ::= SEQUENCE (SIZE (1..max)) OFItemInfo
ItemInfo ::= SEQUENCE {
 itemIdentity  INTEGER (1..max),
 field1        Field1,
 field2        Field2  OPTIONAL, -- Need N
 ...
 [[
 field3-r9  Field3-r9  OPTIONAL,  -- Cond Cond1
 field4-r9  Field4-r9  OPTIONAL  -- Need N
 ]]
}
-- Example with traditional non-critical extension (empty sequence)
BroadcastInfoBlock1 ::= SEQUENCE {
 itemIdentity  INTEGER (1..max),
 field1        Field1,
 field2        Field2  OPTIONAL,  -- Need N
 nonCriticalExtension  BroadcastInfoBlock1-v940-IEs  OPTIONAL
}
BroadcastInfoBlock1-v940-IEs::= SEQUENCE {
 field3-r9  Field3-r9               OPTIONAL,  -- Cond Cond1
 field4-r9  Field4-r9               OPTIONAL,  -- Need N
 nonCriticalExtension  SEQUENCE {}  OPTIONAL   -- Need S
}
-- ASN1STOP

The UE shall, apply the following principles regarding the levels applicable in case of nested error handling:

an extension addition group is not regarded as a level on its own. E.g. in the ASN.1 extract in the previous, a error regarding the conditionality of field3 would result in the entire itemInfo entry to be ignored (rather than just the extension addition group containing field3 and field4);
a traditional nonCriticalExtension is not regarded as a level on its own. E.g. in the ASN.1 extract in the previous, an error regarding the conditionality of field3 would result in the entire BroadcastInfoBlock1 to be ignored (rather than just the non-critical extension containing field3 and field4).

10.5 Not comprehended field p. 1225

The UE shall, when receiving an RRC message on any logical channel:

1 >

if the message includes a field that the UE does not comprehend:

2 >

treat the rest of the message as if the field was absent.