CHOICE Cause Group

M

>Radio Network Layer

>>Radio Network Layer Cause

M

ENUMERATED

(Handover Desirable for Radio Reasons,

Time Critical Handover,

Resource Optimisation Handover,

Reduce Load in Serving Cell,

Partial Handover,

Unknown New eNB UE X2AP ID, Unknown Old eNB UE X2AP ID, Unknown Pair of UE X2AP ID,

HO Target not Allowed,

TX2_RELOCoverall Expiry,

T_RELOCprep Expiry,

Cell not Available,

No Radio Resources Available in Target Cell,

Invalid MME Group ID,

Unknown MME Code, Encryption And/Or Integrity Protection Algorithms Not Supported, ReportCharacteristicsEmpty, NoReportPeriodicity, ExistingMeasurementID, Unknown eNB Measurement ID, Measurement Temporarily not Available,

Unspecified,…,Load Balancing, Handover Optimisation, Value out of allowed range, Multiple E-RAB ID instances, Switch Off Ongoing, Not supported QCI value, Measurement not supported for the object,T_DCoverall Expiry, T_DCprep Expiry,

Action Desirable for Radio Reasons,

Reduce Load,

Resource Optimisation,

Time Critical action,

Target not Allowed,

No Radio Resources Available,

Invalid QoS combination, Encryption Algorithms Not Supported, Procedure cancelled, RRM purpose,

Improve user bit rate,

User Inactivity,

Radio Connection With UE Lost, Failure in the Radio Interface Procedure,

Bearer Option not Supported, MCG Mobility, SCG Mobility, Count reaches max value,

Unknown Old en-gNB UE X2AP ID, PDCP Overload, CHO-CPC resources to be changed, UE Power Saving, Insufficient UE Capabilities, Normal Release, Unknown E-UTRAN node Measurement ID, SCG activation deactivation failure, SCG deactivation failure due to data transmission, UP integrity protection not possible)

>Transport Layer

>>Transport Layer Cause

M

ENUMERATED
(Transport Resource Unavailable,

Unspecified,…)

>Protocol

>>Protocol Cause

M

ENUMERATED
(Transfer Syntax Error,Abstract Syntax Error (Reject),Abstract Syntax Error (Ignore and Notify),Message not Compatible with Receiver State,Semantic Error,Unspecified,Abstract Syntax Error (Falsely Constructed Message),…)

>Misc

>>Miscellaneous Cause

M

ENUMERATED
(Control Processing Overload,
Hardware Failure,O&M Intervention,Not enough User Plane Processing Resources,Unspecified,…)

Cell not Available

The concerned cell is not available.

Handover Desirable for Radio Reasons

The reason for requesting handover is radio related.

Handover Target not Allowed

Handover to the indicated target cell is not allowed for the UE in question

Invalid MME Group ID

The target eNB doesn’t belong to the same pool area of the source eNB i.e. S1 handovers should be attempted instead.

No Radio Resources Available in Target Cell

The target cell doesn’t have sufficient radio resources available.

Partial Handover

Provides a reason for the handover cancellation. The target eNB did not admit all E-RABs included in the HANDOVER REQUEST and the source eNB estimated service continuity for the UE would be better by not proceeding with handover towards this particular target eNB.

Reduce Load in Serving Cell

Load in serving cell needs to be reduced. When applied to handover preparation, it indicates the handover is triggered due to load balancing.

Resource Optimisation Handover

The reason for requesting handover is to improve the load distribution with the neighbour cells.

Time Critical Handover

Handover is requested for time critical reason i.e. this cause value is reserved to represent all critical cases where the connection is likely to be dropped if handover is not performed.

TX2_RELOCoverall Expiry

The reason for the action is expiry of timer TX2_RELOCoverall.

T_RELOCprep Expiry

Handover Preparation procedure is cancelled when timer T_RELOCprep expires.

Unknown MME Code

The target eNB belongs to the same pool area of the source eNB and recognizes the MME Group ID. However, the MME Code is unknown to the target eNB.

Unknown New eNB UE X2AP ID

The action failed because the New eNB UE X2AP ID or the MeNB UE X2AP ID is unknown.

Unknown Old eNB UE X2AP ID

The action failed because the Old eNB UE X2AP ID or the SeNB UE X2AP ID is unknown.

Unknown Pair of UE X2AP ID

The action failed because the pair of UE X2 AP IDs is unknown.

Encryption And/Or Integrity Protection Algorithms Not Supported

The target eNB is unable to support any of the encryption and/or integrity protection algorithms supported by the UE, or the en-gNB is unable to support any of the NR encryption and/or integrity protection algorithms supported by the UE for EN-DC operation.

ReportCharacteristicsEmpty

The action failed because there is no characteristic reported.

NoReportPeriodicity

The action failed because the periodicity is not defined.

ExistingMeasurementID

The action failed because measurement-ID is already used.

Unknown eNB Measurement ID

The action failed because some eNB Measurement-ID is unknown.

Measurement Temporarily not Available

The eNB can temporarily not provide the requested measurement object.

Load Balancing

The reason for mobility settings change is load balancing.

Handover Optimisation

The reason for mobility settings change is handover optimisation.

Value out of allowed range

The action failed because the proposed Handover Trigger parameter change in the eNB₂ Proposed Mobility Parameters IE is too low or too high.

Multiple E-RAB ID Instances

The action failed because multiple instances of the same E-RAB had been provided to the eNB.

Switch Off Ongoing

The reason for the action is an ongoing switch off i.e. the concerned cell will be switched off after offloading and not be available. It aides the receiving eNB in taking subsequent actions, e.g. selecting the target cell for subsequent handovers.

Not supported QCI value

The action failed because the requested QCI is not supported.

Unspecified

Sent when none of the above cause values applies but still the cause is Radio Network Layer related.

Measurement not Supported For The Object

At least one of the concerned cell(s) does not support the requested measurement.

T_DCoverall Expiry

The reason for the action is expiry of timer T_DCoverall.

T_DCprep Expiry

The reason for the action is expiry of timer T_DCprep.

Action Desirable for Radio Reasons

The reason for requesting the action is radio related.
In the current version of this specification applicable for Dual Connectivity and EN-DC only.

Reduce Load

Load in the cell(group) served by the requesting node needs to be reduced.
In the current version of this specification applicable for Dual Connectivity and EN-DC only.

Resource Optimisation

The reason for requesting this action is to improve the load distribution with the neighbour cells.
In the current version of this specification applicable for Dual Connectivity and EN-DC only.

Time Critical action

The action is requested for time critical reason i.e. this cause value is reserved to represent all critical cases where radio resources are likely to be dropped if the requested action is not performed.
In the current version of this specification applicable for Dual Connectivity and EN-DC only.

Target not Allowed

Requested action towards the indicated target cell is not allowed for the UE in question.

In the current version of this specification applicable for Dual Connectivity and EN-DC only.

No Radio Resources Available

The cell(s) in the requested node don’t have sufficient radio resources available.

In the current version of this specification applicable for Dual Connectivity and EN-DC only.

Invalid QoS combination

The action was failed because of invalid QoS combination.

In the current version of this specification applicable for Dual Connectivity and EN-DC only.

Encryption Algorithms Not Supported

The requested eNB is unable to support any of the encryption algorithms supported by the UE.
In the current version of this specification applicable for Dual Connectivity and EN-DC only.

Procedure cancelled

The sending node cancelled the procedure due to other urgent actions to be performed.

In the current version of this specification applicable for Dual Connectivity and EN-DC only.

RRM purpose

The procedure is initiated due to node internal RRM purposes.

In the current version of this specification applicable for Dual Connectivity and EN-DC only.

Improve User Bit Rate

The reason for requesting this action is to improve the user bit rate.

In the current version of this specification applicable for Dual Connectivity and EN-DC only.

User Inactivity

The action is requested due to user inactivity on all E-RABs, e.g., S1 is requested to be released in order to optimise the radio resources; or SeNB/en-gNB didn’t see activity on the DRB recently.

In the current version of this specification applicable for Dual Connectivity and EN-DC only.

Radio Connection With UE Lost

The action is requested due to losing the radio connection to the UE.

In the current version of this specification applicable for Dual Connectivity and EN-DC only.

Failure in the Radio Interface Procedure

Radio interface procedure has failed.

In the current version of this specification applicable for Dual Connectivity and EN-DC only.

Bearer Option not Supported

The requested bearer option is not supported by the sending node.

In the current version of this specification applicable for Dual Connectivity and EN-DC only.

MCG Mobility

The procedure is initiated due to mobility related at MCG radio resource.

SCG Mobility

The procedure is initiated due to mobility related at SCG radio resource.

Count reaches max value

Indicates the PDCP COUNT for UL or DL reached the max value and the bearer may be released.

Unknown Old en-gNB UE X2AP ID

The action failed because the Old en-gNB UE X2AP ID or the SgNB UE X2AP ID is unknown.

PDCP Overload

The procedure is initiated due to PDCP resource limitation.

CHO-CPC resources to be changed

The prepared resources for CHO or CPC for a UE are to be changed.

UE Power Saving

The procedure is initiated to accommodate the preference indicated by UE to release the SCG for UE power saving purpose.

In the current version of this specification applicable for Dual Connectivity and EN-DC only.

Insufficient UE Capabilities

The procedure can’t proceed due to insufficient UE capabilities.

Normal Release

The release is due to normal reasons.

Unknown E-UTRAN node Measurement ID

The action failed because some E-UTRAN node Measurement-ID is unknown.

SCG activation deactivation failure

The action failed due to rejection of the SCG activation deactivation request.

SCG deactivation failure due to data transmission

The SCG deactivation failure due to ongoing or arriving data transmission.

UP integrity protection not possible

The E-RAB can’t be accepted according to the required user plane integrity protection policy.

Transport resource unavailable

The required transport resources are not available.

Unspecified

Sent when none of the above cause values applies but still the cause is Transport Network Layer related

Abstract Syntax Error (Reject)

The received message included an abstract syntax error and the concerned criticality indicated "reject" (see sub clause 10.3 of TS 36.413 [4]).

Abstract Syntax Error (Ignore and Notify)

The received message included an abstract syntax error and the concerned criticality indicated "ignore and notify" (see sub clause 10.3 of TS 36.413 [4]).

Abstract syntax error (falsely constructed message)

The received message contained IEs or IE groups in wrong order or with too many occurrences (see sub clause 10.3 of TS 36.413 [4]).

Message not Compatible with Receiver State

The received message was not compatible with the receiver state (see sub clause 10.4 of TS 36.413 [4]).

Semantic Error

The received message included a semantic error (see sub clause 10.4 of TS 36.413 [4]).

Transfer Syntax Error

The received message included a transfer syntax error (see sub clause 10.2 of TS 36.413 [4]).

Unspecified

Sent when none of the above cause values applies but still the cause is Protocol related

Control Processing Overload

eNB control processing overload

Hardware Failure

eNB hardware failure

Not enough User Plane Processing Resources

eNB has insufficient user plane processing resources available.

O&M Intervention

Operation and Maintenance intervention related to eNB equipment

Unspecified

Sent when none of the above cause values applies and the cause is not related to any of the categories Radio Network Layer, Transport Network Layer or Protocol