14.11 UE autonomous update of virtual active set on non-used frequency (FDD only)

25.3313GPPProtocol specificationRadio Resource Control (RRC)Release 17TS

In the text that follows:

– a "non-used frequency" is a frequency that the UE has been ordered to measure upon but is not used for the connection. A "used frequency" is a frequency that the UE has been ordered to measure upon and is also currently used for the connection;

– a "non-used frequency (resp. cell) considered in an inter-frequency measurement" shall be understood as a non-used frequency (resp. cell) included in the list of cells pointed at in the IE "cells for measurement" if it was received for that measurement, or otherwise as a non-used frequency (resp. cell) included in the "Inter-frequency cell info" part of the variable CELL_INFO_LIST.

For event-triggered inter frequency measurements it is possible to use intra-frequency measurement reporting events for support of maintenance of an active set associated with a non-used frequency considered in that measurement, a "virtual active set" and used in the evaluation of the frequency quality estimates. The "initial virtual active set" for a frequency is the virtual active set that is associated to that frequency just after a message was received that sets up or modifies the inter-frequency measurement.

The way the virtual active sets are initiated and updated for the non-used frequencies considered in an inter-frequency measurement is described in the two subclauses below.

The UE shall support a single virtual active set per non-used frequency for non-CSG measurements if detected set cells are not considered for that frequency.

The UE shall support two virtual active sets per non-used frequency for non-CSG measurements if detected set cells are considered for that frequency – both virtual active sets are maintained using the same rules, and in parallel, however the first virtual active set is maintained considering only cells stored in CELL_INFO_LIST, and the second virtual active set is maintained additionally considering any detected cells (cells stored in CELL_INFO_LIST and cells not stored in CELL_INFO_LIST) and excluding cells indicated in IE "Cells to be excluded in non-used frequency detected cells". This is in order to allow the UE to determine whether or not detected set cells affect the measurement event result. In the following subclauses, the term "virtual active set" applies to both of these virtual active sets (i.e. the virtual active set not containing detected set cells, and the virtual active set containing detected set cells). Elsewhere in the specification, unless stated otherwise, the term "virtual active set" is used to refer to the virtual active set not containing detected set cells.

If any measurement is configured for CSG cells (using CELL_INFO_CSG_LIST) then the UE shall additionally maintain a "CSG virtual active set" for this purpose.

The virtual active set is not initialised and maintained for an inter frequency measurement with periodic reporting. A virtual active set initialised and maintained by another inter-frequency measurement does not affect reporting of the periodic inter-frequency measurement.

14.11.1 Initial virtual active set

If the UE receives a MEASUREMENT CONTROL message that sets up or modifies an inter-frequency measurement and includes the IE "Inter-frequency set update"; or

If at least one cell can be measured on a non-used frequency for which the current virtual active set is empty (see subclause 14.11.2), the UE shall:

1> for each non-used frequency Fi considered in the measurement where cells can be measured:

2> if event 1a is configured for the used frequency in an intra-frequency measurement and the CSG virtual active set is not used:

3> include in the initial virtual active set the Ni cells that have either the greatest downlink Ec/N0 or the greatest downlink RSCP after despreading or the lowest pathloss (the measurement quantity to be used is determined by the IE "intra-frequency measurement quantity" of the intra-frequency measurement from which the event 1a configuration is taken), among the cells on frequency Fi considered in that inter-frequency measurement, where:

if N1a0 and otherwise.

where:

N1a is the "Reporting deactivation threshold" included in the intra-frequency measurement for the first event 1a defined in the intra-frequency measurement with the lowest identity at the time the inter-frequency measurement was received with the IE "Inter-frequency set update" present.

NCells Fi is the number of cells on frequency Fi considered in that inter-frequency measurement.

2> else if the CSG virtual active set is used and event 1c is configured for the used frequency in an intra-frequency measurement:

3> include in the initial CSG virtual active set 1 cell that has either the greatest downlink Ec/N0 or the greatest downlink RSCP after despreading or the lowest pathloss (the measurement quantity to be used is determined by the IE "intra-frequency measurement quantity" of the intra-frequency measurement from which the event 1c configuration is taken), among the cells on frequency Fi in CELL_INFO_CSG_LIST.

i

1

N

2> else:

where:

NCells Fi is the number of cells on frequency Fi considered in that inter-frequency measurement.

NOTE1: The UE initialises the virtual active set with up to the maximum number of inter-frequency cells supported by the UE as defined in [19].

NOTE2: If the UTRAN configures more than one measurement using events 2A, 2B, 2C or 2E the UE measurement capabilities may be exceeded due to the necessary copying of 1A, 1B, 1C criteria. To avoid this the UTRAN may configure one measurement to apply to multiple frequencies so that the 1A, 1B, and 1C criteria will only be copied once.

NOTE3: After a hard handover (see subclause 8.3.5), if the MEASUREMENT CONTROL message that restarts an inter-frequency measurement using the virtual active set does not include the IE "Inter-frequency set update", the UE behaviour regarding the virtual active set is not specified.

14.11.2 Virtual active set update during an inter-frequency measurement

For an inter-frequency measurement, the UE shall:

1> apply the events of type 1a, 1b and 1c that were defined for the used frequency in other stored measurements of type "intra-frequency" at the time the inter-frequency measurement was last received with the IE "Inter-frequency set update" present; and

1> update the virtual active set for the non-used frequencies considered in that measurement according to the following rules:

2> if several events of type 1c were defined for the used frequency when the inter-frequency measurement was last received with the IE "Inter-frequency set update" present, and the inter-frequency measurement applies to cells in the CELL_INFO_CSG_LIST then only the first 1c event that was defined in the measurement with the lowest measurement identity shall apply to the non-used frequencies and replace the "Replacement activation threshold" with 0 to update the CSG virtual active set;

2> if several events of type 1a (resp. 1b,1c) were defined for the used frequency when the inter-frequency measurement was last received with the IE "Inter-frequency set update" present, only the first 1a event (resp 1b, 1c) that was defined in the measurement with the lowest measurement identity shall apply to the non-used frequencies;

2> all the cells considered in the inter-frequency measurements shall be able to affect the reporting range for event 1a and 1b. (i.e. the IE "Cells forbidden to affect reporting range" possibly stored for the intra-frequency measurements on the used frequency does not apply to the non-used frequencies considered in the inter-frequency measurement);

2> the IEs "amount of reporting" and "reporting interval" that were stored for the intra-frequency measurements on the used frequency shall not be considered if reports of the virtual active set updates are needed.

2> the measurement quantity and filter coefficient to be used is determined by the IE "intra-frequency measurement quantity" of the intra-frequency measurement from which the intra-frequency event configuration is taken.

NOTE: If the measurement quantity and filter coefficients to be used differ for the 1a, 1b, and 1c events applied then the UE behaviour is unspecified.

1> if event 1a is applicable to the non-used frequencies considered in the inter-frequency measurement, always only consider monitored cells that are not in the virtual active set for this event, and:

2> when this event is triggered (according to the criteria described in subclause 14.1.2.1) by a cell for a non-used frequency considered in that measurement:

3> if the "Reporting deactivation threshold" is equal to 0, or if the "Reporting deactivation threshold" is different from 0 and the number of cells included in the virtual active set for that frequency is less than or equal to the "Reporting deactivation threshold":

4> add the primary CPICH that enters the reporting range to the "virtual active set".

2> if event 1b is applicable for the non-used frequencies considered in that inter-frequency measurement, always only consider cells in the virtual active set for this event, and when this event is triggered (according to the criteria described in subclause 14.1.2.2) by a cell for a non-used frequency considered in that measurement:

3> if the number of cells included in the virtual active set is greater than 1:

4> remove the primary CPICH that leaves the reporting range from the "virtual active set".

2> if event 1c is applicable for the non-used frequencies considered in that inter-frequency measurement, always only consider monitored cells for this event, and when this event is triggered (according to the criteria described in subclause 14.1.2.3) by a cell for a non-used frequency considered in that measurement:

3> if the "Replacement activation threshold" is equal to 0, or if the "Replacement activation threshold" is different from 0 and the number of cells included in the virtual active set for that frequency is greater than or equal to the "Replacement activation threshold":

4> rank all active and non-active primary CPICHs and take the n best cells to create a new "virtual active set", where n is the number of active primary CPICHs in the "virtual active set".

1> if event 1c is applicable to the non-used frequencies considered in the inter-frequency measurement applying to cells in the CELL_INFO_CSG_LIST, always only consider cells in the CELL_INFO_CSG_LIST, and when this event is triggered (according to the criteria described in subclause 14.1.2.3) by a cell for a non-used frequency considered in that measurement :

2> rank all active and non-active primary CPICHs and take the best cell to create a new "CSG virtual active set".

1> if Event 1a is not defined for the used frequency in other stored measurements of type "intra-frequency" at the time the inter-frequency measurement was set up and the CSG virtual active set is not used for the measurement:

2> the UE shall continuously update the virtual active set to consist of all cells on frequency Fi considered in that inter-frequency measurement.

NOTE: The UE needs to only update the virtual active set with up to the maximum number of interfrequency cells supported by the UE as defined in [19].

If none of the cells that are considered in the measurement on this frequency were measured, the UE may treat the virtual active set as empty and follow the appropriate initialisation procedured in subclause 14.11.1 when any relevant cell can first be measured.

If a cell is a member of the virtual active set and is removed from the variable CELL_INFO_LIST or removed from the list of cells pointed at by the IE "Cells for measurement" for the inter-frequency measurement then the UE shall remove the cell from the virtual active set. (This rule is not applicable for the virtual active set which is used for evaluating detected set cells).

If an inter-frequency measurement that initialised a virtual active set is released, then any virtual active set associated with this measurement shall also be released.