5 Process and procedure descriptions

25.3043GPPRelease 17TSUser Equipment (UE) procedures in idle mode and procedures for cell reselection in connected mode

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

5.1 PLMN selection

5.1.1 General

In the UE, the AS shall report available PLMNs to the NAS on request from the NAS or autonomously.

UE shall maintain a list of allowed PLMN types. The allowed PLMN type can be GSM-MAP only, ANSI-41 only or both. During PLMN selection, based on the list of allowed PLMN types and a list of PLMN identities in priority order, the particular PLMN may be selected either automatically or manually. Each PLMN in the list of PLMN identities can be identified by either ‘PLMN identity’ (GSM-MAP) or ‘SID’. In the system information on the broadcast channel, the UE can receive a ‘PLMN identity’ (GSM-MAP) or a ‘SID’ or a ‘PLMN identity’ (GSM-MAP) and a ‘SID’, in a given cell. For a given cell, the UE might receive several ‘PLMN identities’ from the system information on the broadcast channel. The result of the PLMN selection is an identifier of the selected PLMN, the choice being based on the allowed PLMN types, UE capability or other factors. This identifier is one of either ‘PLMN identity’ for GSM-MAP type of PLMNs or ‘SID’ for ANSI-41 type of PLMNs.

In case that the list of allowed PLMN types includes GSM-MAP, the non-access part of the PLMN selection process is specified in [5]. In the case that list of allowed PLMN types includes ANSI-41, the non-access stratum part of the PLMN selection is specified in TIA/EIA/IS-2000.5 and TIA/EIA/IS-707.

5.1.2 Support for PLMN Selection

5.1.2.1 General

On request of the NAS the AS should perform a search for available PLMNs and report them to NAS.

5.1.2.2 UTRA case

The UE shall scan all RF channels in the UTRA bands according to its capabilities to find available PLMNs. On each carrier, the UE shall search for the strongest cell and read its system information, in order to find out which PLMN the cell belongs to. If the UE can read one or several PLMN identities in the strongest cell, each found PLMN (see the PLMN reading in [4]) shall be reported to the NAS as a high quality PLMN (but without the RSCP value), provided that the following high quality criterion is fulfilled:

1. For an FDD cell, the measured primary CPICH RSCP value shall be greater than or equal to -95 dBm.

2. For a TDD cell, the measured P-CCPCH RSCP shall be greater than or equal to -84 dBm.

Found PLMNs that do not satisfy the high quality criterion, but for which the UE has been able to read the PLMN identities are reported to the NAS together with the CPICH RSCP value for UTRA FDD cells and P-CCPCH RSCP for UTRA TDD cells. The quality measure reported by the UE to NAS shall be the same for each PLMN found in one cell.

The search for PLMNs on the rest of the carriers may be stopped on request of the NAS. The UE may optimise this search by using stored information of carrier frequencies and optionally also information on cell parameters, e.g. scrambling codes, from previously received measurement control information elements.

Once the UE has selected a PLMN, the cell selection procedure shall be performed in order to select a suitable cell of that PLMN to camp on.

If a CSG ID is provided by NAS as part of PLMN selection, the UE shall search for an acceptable or suitable cell belonging to the provided CSG ID to camp on. When the UE is no longer camped on a cell with the provided CSG ID, AS shall inform NAS.

5.1.2.3 GSM case

Support for network selection in GSM is described in [1].

5.1.2.4 E-UTRA case

Support for network selection in E-UTRA is described in [18].

5.2 Cell selection and reselection in idle mode

5.2.1 Introduction

As stated in clause 1, the present document applies to UEs that support at least UTRA.

Different types of measurements are used in different RATs and modes for the cell selection and reselection. The performance requirements for the measurements are specified in [10] and [11].

The NAS can control the RAT(s) in which the cell selection should be performed, for instance by indicating RAT(s) associated with the selected PLMN, and by maintaining a list of forbidden registration area(s) and a list of equivalent PLMNs. The UE shall select a suitable cell and the radio access mode based on idle mode measurements and cell selection criteria.

In order to speed up the cell selection process, stored information for several RATs may be available in the UE.

When camped on a cell, the UE shall regularly search for a better cell according to the cell reselection criteria. If a better cell is found, that cell is selected. The change of cell may imply a change of RAT. Details on performance requirements for cell reselection can be found in [10] and [11].

The NAS is informed if the cell selection and reselection results in changes in the received system information.

For normal service, the UE has to camp on a suitable cell, tune to that cell’s control channel(s) so that the UE can:

– Receive system information from the PLMN;

– Receive registration area information from the PLMN, e.g., location area and routing area; and

– Receive other AS and NAS Information;

– If registered:

– receive paging and notification messages from the PLMN; and

– initiate call setup for outgoing calls or other actions from the UE.

5.2.2 States and state transitions in Idle Mode

Figure 2 shows the states and procedures in Idle Mode.

Figure 2: Idle Mode Cell Selection and Reselection
In any state, a new PLMN selection causes an exit to number 1

5.2.2.1 Cell Selection process overview

Whenever a PLMN has been selected by NAS, the UE shall attempt to find a suitable cell to camp on.

The NAS may control the cell selection by:

– providing information on RAT(s) associated with the selected PLMN;

– maintaining lists of forbidden registration areas;

– providing a list of equivalent PLMNs;

One or several RATs may be associated with the selected PLMN. In [5] it is specified which RAT a UE shall select to search for a suitable cell of the selected PLMN.

The AS shall attempt to find a suitable cell to camp on as specified in clause 5.2.3.

When the MBMS frequency layer dispersion is triggered, the UE actions are specified in [4].

If a suitable cell is found, the UE shall select this cell to camp on, and report this event to NAS so that the necessary NAS registration procedures can be performed. When the registration is successful, the UE enters in state Camped normally in order to obtain normal service.

If the UE is unable to find any suitable cell of selected PLMN the UE shall enter the Any cell selection state.

5.2.2.2 Camped normally state overview

In this state, the UE obtains normal service and performs the tasks specified in 5.2.5.

If after a Cell reselection evaluation process a better cell is found, the Cell reselection procedure is performed. If no suitable cell is found, the UE shall enter the state Any cell selection.

If a necessary NAS registration is rejected, the UE shall enter the Any cell selection state, except if the LR is rejected with cause #12, cause #14, cause #15 or cause #25. In this case the UE shall behave as specified in [5] and [16].

When UE leaves idle mode in order to enter the state Connected mode, the UE shall attempt to access the current serving cell. If the access attempt to the serving cell fails, the UE shall use the Cell reselection evaluation procedure.

5.2.2.3 Connected mode State overview

The procedures in Connected mode state are specified in [4]

When returning to idle mode, the UE shall use the procedure Cell selection when leaving connected mode in order to find a suitable cell to camp on and enter state Camped normally. If a suitable cell is found, then the AS reports this event to NAS to be capable to perform necessary NAS registration procedures. If no suitable cell is found, the Stored information cell selection procedure shall be used.

If no suitable cell is found in cell reselection evaluation process, the UE enters the state Any cell selection.

5.2.2.4 Any cell selection State overview

In this state the UE performs the tasks specified in subclause 5.2.8

The state Any cell selection is also entered if the NAS indicates that a location registration is rejected except if the LR is rejected with cause #12, cause #14, cause #15 or cause #25, see [5] and [16], or if there is no USIM in the UE.

If the UE received an LR reject with cause #12, cause #14, cause #15 or cause #25, the UE shall behave as specified in [5] and [16].

If an acceptable cell is found, the UE shall inform the NAS and camp on this cell and obtain limited service, state Camped on any cell. The subsequent actions of the NAS regarding the PLMN selection are specified in [5].

5.2.2.5 Camped on any cell State overview

In this state the UE obtains limited service and shall behave as specified in subclause 5.2.9. In this state if the UE supports CS voice services, the UE shall avoid reselecting an acceptable cell of E-UTRA regardless of priorities provided in system information of current cell. The UE shall regularly attempt to find a suitable cell, trying all RATs that are supported by the UE. If a suitable cell is found, this causes an exit to number 2 in figure 2.

NOTE: The ‘PLMN selection’ process may select a new PLMN at any time in idle mode, which in Figure 2 causes an exit to number 1.

5.2.3 Cell Selection Process

5.2.3.1 UTRA case

5.2.3.1.1 Description

The UE shall use one of the following two search procedures:

a) Initial Cell Selection

This procedure requires no prior knowledge of which RF channels are UTRA carriers. The UE shall scan all RF channels in the UTRA bands according to its capabilities to find a suitable cell. On each carrier, the UE need only search for the strongest cell. Once a suitable cell is found this cell shall be selected.

b) Stored Information Cell Selection

This procedure requires stored information of carrier frequencies and optionally also information on cell parameters, e.g. scrambling codes, from previously received measurement control information elements. Once the UE has found a suitable cell the UE shall select it. If no suitable cell is found the Initial cell selection procedure shall be started.

5.2.3.1.2 Criteria

The cell selection criterion S is fulfilled when:

Where:

the signalled values QqualminOffset and QrxlevminOffset are only applied when a cell is evaluated for cell selection as a result of a periodic search for a higher priority PLMN while camped normally in a VPLMN [5]. During this periodic search for higher priority PLMN the UE may check the S criteria of a cell using parameter values stored from a different cell of this higher priority PLMN.

Squal	Cell Selection quality value (dB) Applicable only for FDD cells.
Srxlev	Cell Selection RX level value (dB)
Qoffset_temp	Offset temporarily applied to a cell as specified in [4] (dB)
Q_qualmeas	Measured cell quality value. The quality of the received signal expressed in CPICH Ec/N0 (dB) for FDD cells. CPICH Ec/N0 shall be averaged as specified in [10]. Applicable only for FDD cells.
Q_rxlevmeas	Measured cell RX level value. This is received signal, CPICH RSCP for FDD cells (dBm) and P-CCPCH RSCP for TDD cells (dBm).
Qqualmin	Minimum required quality level in the cell (dB). Applicable only for FDD cells.
QqualminOffset	Offset to the signalled Qqualmin taken into account in the Squal evaluation as a result of a periodic search for a higher priority PLMN while camped normally in a VPLMN [5]
Qrxlevmin	Minimum required RX level in the cell (dBm)
QrxlevminOffset	Offset to the signalled Qrxlevmin taken into account in the Srxlev evaluation as a result of a periodic search for a higher priority PLMN while camped normally in a VPLMN [5]
Pcompensation	max(UE_TXPWR_MAX_RACH – P_MAX, 0) (dB)
UE_TXPWR_MAX_RACH	Maximum TX power level an UE may use when accessing the cell on RACH (read in system information) (dBm)
P_MAX	Maximum RF output power of the UE (dBm)

5.2.3.2 GSM case

The cell selection criteria and procedures in GSM are specified in [1].

5.2.3.3 E-UTRA case

The cell selection criteria and procedures in E-UTRA are specified in [18].

5.2.3.4 CSG cells and Hybrid cells in Cell Selection

In addition to normal cell selection rules a manual selection of CSGs shall be supported by the UE upon request from higher layers as defined in subclause 5.6.

5.2.4 Void

5.2.5 Camped Normally State

5.2.5.1 UTRA case

When camped normally, the UE shall perform the following tasks:

– select and monitor the indicated PICH and PCH of the cell as specified in clause 8 according to information sent in system information;

– monitor relevant System Information. This is specified in [4];

– perform necessary measurements for the cell reselection evaluation procedure;

– execute the cell reselection evaluation process on the following occasions/triggers:

1) UE internal triggers, so as to meet performance as specified in [10] and [11];

2) When information on the BCCH used for the cell reselection evaluation procedure has been modified

If the UE supports MBMS and MBMS is active in the cell and the UE is permitted to receive MBMS services in the cell, the UE shall perform MBMS tasks as specified in subclause 6.3.

5.2.5.2 GSM case

The Camped Normally State is specified in [1].

5.2.5.3 E-UTRA case

The Camped Normally State is specified in [18].

5.2.6 Cell Reselection Evaluation Process

5.2.6.1 UTRA case

The cell reselection process is specified in the following sub-clauses:

5.2.6.1.0 Use of MBMS PL

In the cell reselection process, an MBMS PL shall only be applicable while the UE is receiving an MBMS session from one or more of the ongoing activated MBMS services for which this PL is indicated.

5.2.6.1.1 Measurement rules for cell re-selection when HCS is not used

The measurement rules below apply in Idle, URA_PCH, CELL_PCH states. For FDD, 3.84 Mcps TDD and 7.68 Mcps TDD, in CELL_FACH state the measurement rules below apply only if HS-DSCH discontinuous reception, with or without second DRX cycle, is configured, as specified in [4] and according to the requirements specified in [10]. Otherwise, the UE is required to perform measurements on all intra-frequency, inter-frequency and inter-RAT cells listed in system information according to requirements specified in [10]. For 1.28 Mcps TDD, in CELL_FACH state the UE is required to perform measurements on all intra-frequency, inter-frequency and inter-RAT cells listed in system information according to requirements specified in [11]. In Idle, URA_PCH, CELL_PCH and CELL_FACH states the UE shall only consider those cells the UE is mandated to measure according to the measurement rules below as measured cells in the cell reselection criteria (subclause 5.2.6.1.4).

If the system information broadcast in the serving cell indicates that HCS is not used, then for intra-frequency and inter-frequency measurements and inter-RAT measurements, the UE shall:

– use Squal for FDD cells and Srxlev for TDD for Sx, and apply the following rules.

1. If Sx > S_intrasearch, UE may choose to not perform intra-frequency measurements.
If Sx <= S_intrasearch,perform intra-frequency measurements.
If S_intrasearch,is not sent for serving cell, perform intra-frequency measurements.

If the system information broadcast in the serving cell indicates that HCS is not used and absolute priorities for inter-frequency layers are not provided, then for inter-frequency measurements the UE shall:

2. If Sx > S_intersearch and MBMS PL has not been indicated, and Srxlev > S_searchHCS if S_searchHCS is signalled, UE may choose to not perform inter-frequency measurements.
If Sx > S_intersearchand MBMS PL has been indicated and the serving cell belongs to the MBMS PL, and Srxlev > S_searchHCS if S_searchHCS is signalled, UE may choose to not perform inter-frequency measurements.
If Sx > S_intersearch, and MBMS PL has been indicated and the serving cell does not belong to the MBMS PL, and Srxlev > S_searchHCS if S_searchHCS is signalled, UE shall at least perform inter-frequency measurements on the MBMS PL.
If Sx <= S_intersearch, or Srxlev <= S_searchHCS if S_searchHCS is signalled, perform inter-frequency measurements.
If S_intersearch, is not sent for serving cell, perform inter-frequency measurements.
If Dedicated CSG frequencies have been indicated by system information the UE may choose not to perform inter-frequency measurments of these frequencies.

If the system information broadcast in the serving cell indicates that HCS is not used and absolute priorities for some inter-RAT layers are not provided, then for inter-RAT measurements on RATs for which absolute priority information is not provided the UE shall:

3. If Sx > Ssearch_{RAT m}, and Srxlev > S_HCS,RATm if S_HCS,RATm is signalled, UE may choose to not perform measurements on cells of RAT "m".
If Sx <= Ssearch_{RAT m}, or Srxlev <= S_HCS,RATm if S_HCS,RATm is signalled, perform measurements on cells of RAT "m".
If Ssearch_{RAT m}, is not sent for serving cell, perform measurements on cells of RAT "m".

If HCS is not used and if S_{limit,SearchRATm} is sent for serving cell, UE shall ignore it.

NOTE: The presence of S_searchHCS and S_HCS,RATm thresholds in system information are used to avoid introducing new parameters to system information and their presence does not imply that HCS is used.

5.2.6.1.1a High-mobility state when HCS is not used

High-mobility state, as applied in HCS case, is also applicable in non-HCS if the parameters non-HCS_ T_CRmax, non-HCS_N_CR and non-HCS_T_CRmaxhyst are sent on the system information broadcast.

If in non-HCS environment the number of cell reselections during time period non-HCS_T_CRmax exceeds non-HCS_N_CR, or if the network (via RRC signalling) has ordered the UE to consider itself to be in high-mobility state, then high-mobility state has been detected.

When the number of cell reselections during time period non-HCS_T_CRmax no longer exceeds non-HCS_N_CR, the UE shall:

– continue in high-mobility state.

– if the criteria for entering high-mobility state is not detected during time period non-HCS-T_CrmaxHyst:

– exit high-mobility state.

If the UE is in non-HCS environment and in high-mobility state, the UE shall apply the speed dependent scaling rules as defined in subclause 5.2.6.1.4.

5.2.6.1.2 Measurement rules for cell re-selection when HCS is used

The UE shall not use HCS for inter-frequency reselection if absolute priority based cell reselection (see subclause 5.2.6.1.4a) is used for inter-frequency reselection. The UE shall not use HCS for inter-RAT reselection if absolute priority based cell reselection (see subclause 5.2.6.1.4a) is used for that RAT.

Use Squal for FDD cells and Srxlev for TDD cells for Sx and apply the following rules.

If the system information broadcast in the serving cell indicates that HCS is used, then for intra-frequency and inter-frequency measurements, the UE shall:

use HCS priority₁ as the HCS priority broadcast in the system information and apply the following rule:

IF an MBMS PL is used THEN

– If the UE is not in high-mobility state, for serving cell and neighbour cells belonging to the MBMS PL set the HCS priority = HCS priority₁ + HCS_OFF_mbms.

– If the UE is in high-mobility state, for serving cell and neighbour cells belonging to the MBMS PL set the HCS priority = HCS priority₁.

– for serving cell and neighbour cells not belonging to the MBMS PL, set the HCS priority = HCS priority_1.

IF an MBMS PL is not used THEN

For serving cell and all neighbour cells set HCS priority = HCS priority₁

Then apply this to the following:

1. For intra-frequency and inter-frequency measurement rules for UEs not in high-mobility state

IF (Srxlev_s <= Ssearch_HCS) or (if FDD and S_x <= S_intersearch) THEN

measure on all intra-frequency and inter-frequency cells.

ELSE

IF (S_x > S_intrasearch) THEN

measure on all intra-frequency and inter-frequency cells, which have higher HCS priority level than the serving cell

ELSE

measure on all intra-frequency and inter-frequency cells, which have equal or higher HCS priority level than the serving cell

ENDIF

IF (S_intrasearch is not sent for the serving cell) THEN

measure on all intra-frequency cells. UEs in high-mobility state may also use this rule.

measure on all inter-frequency cells, which have higher HCS priority level than the serving cell unless measurement rules for UEs in high-mobility state are triggered.

ENDIF

If HCS is used and if S_searchHCS or S_intersearch(in FDD) are not sent for the serving cell, UE shall:

measure on all intra-frequency and inter-frequency cells.

2. For intra-frequency and inter-frequency measurement rules for UE’s in high-mobility state:

If the number of cell reselections during time period T_CRmax exceeds N_CR, or if the network (via RRC signalling) has ordered the UE to consider itself in high-mobility state, then high-mobility state has been detected. In this high-mobility state, the UE shall

IF (Srxlev_s <= Ssearch_HCS) or (if FDD and S_x <= S_intersearch), or S_searchHCS or S_intersearch(in FDD) are not sent for the serving cell THEN

measure on all intra-frequency and inter-frequency cells.

ELSE

measure intra-frequency and inter-frequency neighbouring cells, which have equal or lower HCS priority than serving cell.

ENDIF

When the number of cell reselections during time period T_CRmax no longer exceeds N_CR, UE shall

– continue these measurements during time period T_CrmaxHyst

– if the criteria for entering high-mobility state is not detected during time period T_CrmaxHyst:

– exit high-mobility state.

If Dedicated CSG frequencies have been indicated by System Information the UE may choose not to perform inter-frequency measurements of these frequencies.

When serving cell belongs to a hierarchical cell structure, the UE shall follow these rules for Inter-RAT measurements:

1. Inter-RAT threshold-based measurement rules for UEs not in high-mobility state

IF (Srxlev_s <= S_HCS,RATm) or (if FDD and S_x <= S_SearchRATm) THEN

UE shall measure on all inter-RATm cells.

ELSE

IF (S_x > S_{limit,SearchRATm}) THEN

UE may choose to not measure neighbouring cells in RAT "m".

ELSE

UE shall measure on all neighbouring cells in RAT "m", which have equal or higher HCS priority level than the serving cell

ENDIF

If HCS is used and if S_HCS,RATmis not sent for the serving cell, UE shall measure on all inter-RATm cells.

2. Inter-RAT measurement rules for UEs in high-mobility state

– If the number of cell reselections during time period T_CRmax exceeds N_CR, or if the network (via RRC signalling) has ordered the UE to consider itself in high-mobility state, then high-mobility state has been detected. In this high-mobility state, the UE shall

– IF (Srxlev_s <= S_HCS,RATm) or (if FDD and S_x <= S_SearchRATm), or S_HCS,RATmor S_SearchRATm are not sent for the serving cell THEN

– UE shall measure on all inter-RATm cells.

ELSE

– measure the neighbouring cells in RAT "m", which have an equal or lower HCS priority than the serving cell

– ENDIF

When the number of cell reselections during time interval T_CRmax no longer exceeds N_CR, UE shall

– continue these measurements during time period T_CrmaxHyst

– if the criteria for entering high-mobility state is not detected during time period T_CrmaxHyst

– exit high-mobility state.

5.2.6.1.2a Measurement rules for inter-frequency and inter-RAT cell reselection when absolute priorities are used

The measurement rules below apply in Idle, URA_PCH, CELL_PCH states. In CELL_FACH state, if (High Priority Layers is indicated in CELL_FACH Absolute Priority Measurement Indicator [4] and SrxlevServingCell > Sprioritysearch1 and SqualServingCell > Sprioritysearch2) or (All Layers is indicated in CELL_FACH Absolute Priority Measurement Indicator [4]) then the measurement rules below apply, otherwise the measurement rules in 5.2.6.1.1 and 5.2.6.1.2 apply.

The UE is required to perform measurements of inter-frequency and inter-RAT cells listed in system information according to Measurement requirements are specified in [10]. UE specific priorities are not applied in camped on any cell state.

If the UE has received absolute priority information for inter-frequency layers, the UE shall follow these rules:

– The UE shall perform measurements of inter-frequency layers with a priority higher than the priority of the current serving layer.

NOTE: The rate of these measurements may vary depending on whether Srxlev and Squal of the serving cell are above or below S_{prioritysearch1}and S_{prioritysearch2}. This is specified in [10].

– When the UE in camped normally state, has only dedicated priorities other than for the current frequency, the UE shall consider the current frequency to be the lowest priority frequency (i.e. lower than any of network configured values).

– For inter-frequency layers with a priority equal or lower than the priority of the current serving layer:

– If Srxlev_ServingCell > S_{prioritysearch1} and Squal_ServingCell > S_{prioritysearch2} the UE may choose not to perform measurements of inter-frequency layers of equal or lower priority.

– If Srxlev_ServingCell <= S_{prioritysearch1} or Squal_ServingCell <= S_{prioritysearch2} the UE shall perform measurements of inter-frequency layers of equal or lower priority.

– The UE may choose not to perform measurements of inter-frequency layers for which the UE has no absolute priority.

If the UE has received absolute priority information for inter-RAT layers, the UE shall follow these rules:

– The UE shall perform measurements of inter-RAT layers with a priority higher than the priority of the current serving cell.

NOTE: The rate of these measurements may vary depending on whether Srxlev and Squal of the serving cell are above or below S_{prioritysearch1} and S_{prioritysearch2}. This is specified in [10].

– For inter-RAT layers with a priority lower than the priority of the current serving cell:

– If Srxlev_ServingCell > S_{prioritysearch1} and Squal_ServingCell > S_{prioritysearch2} the UE may choose not to perform measurements of inter-RAT layers of lower priority.

– If Srxlev_ServingCell <= S_{prioritysearch1} or Squal_ServingCell <= S_{prioritysearch2} the UE shall perform measurements of inter-RAT layers of lower priority.

– If absolute priority information is provided for any inter-RAT layers in a RAT, the UE may choose not to perform measurements on layers in that RAT for which the UE has no absolute priority.

– The UE shall perform measurements according to subclause 5.2.6.1.1 for inter-RAT layers for which the UE has no absolute priority. For all inter-RAT layers belonging to one RAT, either the rules above or the rules in subclause 5.2.6.1.1 or 5.2.6.1.2 shall apply.

– In CELL_FACH state: If there are UTRAN inter-frequency, GERAN and E-UTRAN neighbours configured and required to be measured according to the measurement rules above, then the UE shall perform measurements on UTRAN inter-frequency and E-UTRAN layers (i.e. the UE is not required to measure GERAN, regardless of whether GERAN has absolute priorities assigned).

5.2.6.1.3 Highest ranked cells with cell reservations, access restrictions or unsuitable for normal camping

For the highest ranked cell (including serving cell) according to cell reselection criteria specified in subclause 5.2.6.1.4, or for the best cell according to absolute priority reselection criteria specified in subclause 5.2.6.1.4a, the UE shall check if the access is restricted according to the rules in subclause 5.3.1.1.

If that cell and other cells have to be excluded from the candidate list, as stated in subclause 5.3.1.1, the UE shall not consider these as candidates for cell reselection. This limitation is removed when the highest ranked cell changes.

If the highest ranked cell or best cell according to absolute priority reselection rules is an intra-frequency or inter-frequency cell which is not suitable due to being part of the "list of forbidden LAs for roaming" or belonging to a PLMN which is not indicated as being equivalent to the registered PLMN, the UE shall not consider this cell and other cells on the same frequency, as candidates for reselection for a maximum of 300s. If the UE has to perform an any cell selection procedure any limitation shall be removed. If the UE is redirected under UTRAN control to a frequency for which the timer is running, any limitation on that frequency shall be removed.

If the highest ranked cell or best cell according to absolute priority reselection rules is an inter-RAT cell which is not suitable due to being part of the "list of forbidden LAs for roaming" or belonging to a PLMN which is not indicated as being equivalent to the registered PLMN, the UE shall not consider this cell and other cells on the same frequency as candidates for reselection for a maximum of 300s. If the UE has to perform an any cell selection procedure any limitation shall be removed. If the UE is redirected under UTRAN control to a frequency for which the timer is running, any limitation on that frequency shall be removed.

5.2.6.1.4 Cell Reselection Criteria

The following cell re-selection criteria are used for intra-frequency cells, inter-frequency cells if no absolute priority information for any inter-frequency layer is available to the UE, and inter-RAT cells if no absolute priority information for any inter-RAT layer is available to the UE for that RAT. For inter-frequency and inter-RAT layers in a RAT for which absolute priorities are defined, then the cell reselection criteria in subclause 5.2.6.1.4a shall apply.

The quality level threshold criterion H for hierarchical cell structures is used to determine whether prioritised ranking according to hierarchical cell re-selection rules shall apply, and is defined by:

If it is indicated in system information that HCS is not used, the quality level threshold criterion H is not applied.

The cell-ranking criterion R is defined by:

where:

– the signalled value Qoffmbms is only applied to those cells (serving or neighbouring) belonging to the MBMS PL

– for a CSG cell not included in the neighbour cell list, then Qoffsets,n and Qoffmbms have the value 0.

where:

TEMP_OFFSET_n applies an offset to the H and R criteria for the duration of PENALTY_TIME_n after a timer T_n has started for that neighbouring cell.

TEMP_OFFSET_n and PENALTY_TIME_nare only applicable if the usage of HCS is indicated in system information.

For a CSG cell not included in the neighbour cell list, then TEMP_OFFSET_n has the value of 0.

The timer T_n is implemented for each neighbouring cell. T_n shall be started from zero when one of the following conditions becomes true:

– if HCS_PRIO_n <> HCS_PRIO_s and

Q_meas,_n>= Qhcs_n

– if HCS_PRIO_n = HCS_PRIO_s and

– for serving FDD and neighbour FDD cells if the quality measure for cell selection and reselection is set to CPICH RSCP in the serving cell, and:

Q_meas,n > Q_meas,_s+ Qoffset1_s,n

– for serving FDD and neighbour FDD cells if the quality measure for cell selection and reselection is set to CPICH Ec/No in the serving cell, and:

Q_meas,n > Q_meas,_s+ Qoffset2_s,n

– for all other serving and neighbour cells:

Q_meas,n > Q_meas,_s+ Qoffset1_s,n

T_n for the associated neighbour cell shall be stopped as soon as any of the above conditions are no longer fulfilled. Any value calculated for TO_n is valid only if the associated timer T_n is still running else TO_n shall be set to zero.

At cell-reselection, a timer T_n is stopped only if the corresponding cell is not a neighbour cell of the new serving cell, or if the criteria given above for starting timer T_n for the corresponding cell is no longer fulfilled with the parameters of the new serving cell. On cell re-selection, timer T_n shall be continued to be run for the corresponding cells but the criteria given above shall be evaluated with parameters broadcast in the new serving cell if the corresponding cells are neighbours of the new serving cell.

S_n

Cell Selection value of the neighbouring cell, (dB)

Q_meas

Quality value. The quality value of the received signal derived from the averaged CPICH Ec/No or CPICH RSCP for FDD cells, from the averaged P-CCPCH RSCP for TDD cells and from the averaged received signal level for GSM cells. The averaging of these measurement quantities are performed as specified in [10] and [11]. For FDD cells, the measurement that is used to derive the quality value is set by the Cell_selection_and_reselection_quality_measure information element.

Cell reselection parameters broadcast in system information are listed in subclause 5.2.6.1.5.

The cell selection criterion S used for cell reselection is fulfilled when:

Where :

Squal	Cell Selection quality value (dB) Applicable only for FDD cells and E-UTRA cells.
Srxlev	Cell Selection RX level value (dB)
Qoffset_temp	Offset temporarily applied to a cell as specified in [4] (dB)
Q_qualmeas	Measured cell quality value. The quality of the received signal expressed in CPICH Ec/N0 (dB) for FDD cells, and RSRQ for E-UTRA cells. CPICH Ec/N0 and RSRQ shall be averaged as specified in [10]. Applicable only for FDD cells and E-UTRA cells.
Q_rxlevmeas	Measured cell RX level value. This is received signal, CPICH RSCP for FDD cells (dBm), P-CCPCH RSCP for TDD cells (dBm), the averaged received signal level as specified in [10] for GSM cells (dBm) and the averaged RSRP as specified in [10] for E-UTRA cells (dBm). CPICH RSCP, P-CCPCH RSCP, the received signal level for GSM cells and the RSRP for E-UTRA cells shall be averaged as specified in [10] and [11].
Qqualmin	Minimum required quality level in the cell (dB). Applicable only for FDD cells and E-UTRA cells.
Qrxlevmin	Minimum required RX level in the cell (dBm)
Pcompensation	max(UE_TXPWR_MAX_RACH – P_MAX, 0) (dB)
UE_TXPWR_MAX_RACH	Maximum TX power level an UE may use when accessing the cell on RACH (read in system information) (dBm)
P_MAX	Maximum RF output power of the UE (dBm)

For a CSG cell not included in the neighbour cell list, the cell specific parameter values to be used shall be the same as the serving cell.

If HCS is not used in the serving cell the UE shall perform ranking of all cells that fulfil the criterion S, among:

– all measured cells (see subclause 5.2.6.1.1).

If HCS is used in the serving cell, then from the cells that fulfil the criterion S, the UE shall perform ranking of all cells among

1. when not in high-mobility state (see subclause 5.2.6.1.2),

– all measured cells, that have the highest HCS_PRIO among those cells that fulfil the criterion H >= 0.

– all measured cells, not considering HCS priority levels, if no cell fulfil the criterion H >= 0.

2 when in high-mobility state (see subclause 5.2.6.1.2),

– all measured cells, and among these cells:

– if there are cells with a lower HCS priority than the serving cell that fulfil the criterion H >= 0:

– from the cells that have a lower HCS priority than the serving cell, all cells that have the highest HCS_PRIO among those cells that fulfil the criterion H >=0;

– else:

– if there are cells that fulfil the criterion H >= 0 with an HCS priority higher or equal to the HCS priority of the serving cell:

– from the cells that have an HCS priority higher or equal to the HCS priority of the serving cell, all cells that have the lowest HCS_PRIO among those cells that fulfil the criterion H >=0;

– else

– all cells not considering HCS priority levels.

The cells shall be ranked according to the R criteria specified above, deriving Q_meas,nand Q_meas,sand calculating the R values using CPICH RSCP, P-CCPCH RSCP and the averaged received signal level as specified in [10] and [11] for FDD, TDD and GSM cells, respectively.

The offset Qoffset1_s,nis used for Qoffset_s,nto calculate R_n, the hysteresis Qhyst1_s is used for Qhyst_s to calculate R_s. For UE in RRC connected mode states CELL_PCH or URA_PCH the hysteresis Qhyst_s takes the value Qhyst1_s,PCH to calculate R_s, if provided in SIB4 [see 4]. For UE in RRC connected mode state CELL_FACH the hysteresis Qhyst_s takes the value Qhyst1_s,FACH to calculate R_s, if provided in SIB4 [see 4].

If the usage of HCS is indicated in system information, TEMP_OFFSET1_n is used for TEMP_OFFSET_n to calculate TO_n. If it is indicated in system information that HCS is not used, TEMP_OFFSET_n is not applied when calculating R_n. The best ranked cell is the cell with the highest R value.

If a TDD or GSM cell is ranked as the best cell, then the UE shall perform cell re-selection to that TDD or GSM cell.

If an FDD cell is ranked as the best cell and the quality measure for cell selection and re-selection is set to CPICH RSCP, the UE shall perform cell re-selection to that FDD cell. If this cell is found to be not suitable, the UE shall behave according to subclause 5.2.6.1.3.

If an FDD cell is ranked as the best cell and the quality measure for cell selection and re-selection is set to CPICH Ec/No, the UE shall perform a second ranking of the FDD cells according to the R criteria specified above, but using the measurement quantity CPICH Ec/No for deriving the Q_meas,nand Q_meas,sand calculating the R values of the FDD cells. The offset Qoffset2_s,n is used for Qoffset_s,n to calculate R_n, the hysteresis Qhyst2_s is used for Qhyst_s to calculate R_s. For UE in RRC connected mode states CELL_PCH or URA_PCH the hysteresis Qhyst_s takes the value Qhyst2_s,PCH to calculate R_s, if provided in SIB4 [see 4]. For UE in RRC connected mode state CELL_FACH the hysteresis Qhyst_s takes the value Qhyst2_s,FACH to calculate R_s, if provided in SIB4 [see 4]. If the usage of HCS is indicated in system information, TEMP_OFFSET2_n is used to calculate TO_n. If it is indicated in system information that HCS is not used, TEMP_OFFSET_n is not applied when calculating R_n. Following this second ranking, the UE shall perform cell re-selection to the best ranked FDD cell. If this cell is found to be not suitable, the UE shall behave according to subclause 5.2.6.1.3.

In all cases, the UE shall reselect the new cell, only if the following conditions are met:

– the new cell is better ranked than the serving cell during the preceding time interval Treselection. For UE in RRC connected mode states CELL_PCH or URA_PCH the interval Treselection_s,PCH applies, if provided in SIB4 [see 4], while for UE in RRC connected mode state CELL_FACH the interval Treselection_s,FACH applies, if provided in SIB4 [see 4]. For hierarchical cell structures when high-mobility state has not been detected, if according to the HCS rules the serving cell is not ranked then all the ranked cells are considered to be better ranked than the serving cell. In case the UE reselects to a cell on an MBMS preferred frequency to receive an MBMS service not available on the current frequency the UE may reduce interval Treselection_S, Treselection_{S, PCH} and Treselection_{S, FACH}.

Additionally the UE shall apply the following scaling rules to Treselection_s or Treselection_s,PCH or Treselection_s,FACH:

– For intra-frequency cells and high-mobility state not detected:

– no scaling applied.

– For intra-frequency cells and high-mobility state is detected:

– multiply Treselection_s or Treselection_s,PCH or Treselection_s,FACH by the IE "Speed dependent ScalingFactor for Treselection" if sent on system information.

– For inter-frequency cells and high-mobility state not detected:

– multiply Treselection_s or Treselection_s,PCH or Treselection_s,FACH by the IE "Inter-frequency ScalingFactor for Treselection" if sent on system information.

– For inter-frequency cells and high-mobility state is detected:

– multiply Treselection_s or Treselection_s,PCH or Treselection_s,FACH by both the IEs "Speed dependent ScalingFactor for Treselection" if sent on system information and "Inter-frequency ScalingFactor for Treselection" if sent on system information.

– For inter-RAT cells and high-mobility state not detected:

– multiply Treselection_s or Treselection_s,PCH or Treselection_s,FACH by the IE "Inter-RAT ScalingFactor for Treselection" if sent on system information.

– For inter-RAT cells and high-mobility state is detected:

– multiply Treselection_s or Treselection_s,PCH or Treselection_s,FACH by both the IEs "Speed dependent ScalingFactor for Treselection" if sent on system information and "Inter-RAT ScalingFactor for Treselection" if sent on system information.

In case scaling is applied to Treselection_s or Treselection_s,PCH, the UE shall round up the result after all scalings to the nearest second. In case scaling is applied to Treselection_s,FACH, the UE shall round up the result after all scalings to the nearest 0.2 seconds.

– more than 1 second has elapsed since the UE camped on the current serving cell.

– For FDD the UE does not have an allocated common E-DCH resource.

– For 1.28 Mcps TDD, the UE does not have CELL Reselection Indication procedure ongoing.

For FDD the UE continues taking intra-frequency measurements and ranking cells while it has an allocated common E-DCH resource. If supported by the UE and configured to perform Cell Reselection Indication Reporting, the UE shall inform the MAC layer that the cell reselection criteria are met.

For 1.28 Mcps TDD, the UE continues taking measurements and ranking cells while it has the CELL Reselection Indication procedure ongoing as in [19].

5.2.6.1.4a Absolute priority based criteria for inter-frequency and inter-RAT cell reselection

Absolute priorities of different absolute priority layers may be provided to the UE. The following cell reselection criteria are used for inter-frequency cells if absolute priority information for inter-frequency is available to the UE, and inter-RAT cells if absolute priority information for inter-RAT is available to the UE.

If System Information Block 18 with UTRAN information is provided then the UE shall apply the inter-frequency priority rules below only to UTRAN cells of the selected PLMN or equivalent PLMNs. If System Information Block 18 is not provided, or is provided but contains no information for UTRAN, then the rules below apply for the entire UTRAN RAT.

If System Information Block 18 with GERAN information is provided then the UE shall apply the GERAN RAT priority rules below only to GERAN cells of the selected PLMN or equivalent PLMNs. If System Information Block 18 is not provided, or is provided but contains no information for GERAN, then the rules below apply for the entire GERAN RAT.

If priority information is provided for any inter-frequency layers, cells belonging to inter-frequency layers for which no priority or no threshold is assigned shall not be considered for reselection.

If priority information is provided for any inter-RAT layers in a RAT, cells belonging to layers in that RAT for which no priority or no threshold is assigned shall not be considered for reselection.

If none of the inter-frequency layers in UTRAN are provided with both priority and threshold parameters, the cell reselection criteria in subclause 5.2.6.1.4 shall apply for inter-frequency layers in UTRAN.

If none of the inter-RAT layers in a RAT are provided with both priority and threshold parameters, the cell reselection criteria in subclause 5.2.6.1.4 shall apply for that RAT.

If both criteria in subclause 5.2.6.1.4 and criteria in subclause 5.2.6.1.4a are simultaneously fullfilled, the order in which the reselection criteria are evaluated is left to UE implementation.

NOTE: In order not to apply absolute priority but the cell reselection criteria in subclause 5.2.6.1.4 for inter-frequencies cell reselection in UTRAN or for inter-RAT cell reselection, the network may choose to configure no inter-frequency layers in UTRAN or no inter-RAT layers in a RAT in SIB19 even though dedicated priorities are provided.

For all inter-frequency layers or all inter-RAT layers belonging to one RAT, either the criteria below or the criteria in subclause 5.2.6.1.4 shall apply.

The UE may apply either priorities broadcast in system information or priorities received through dedicated signalling. The rules regarding which set of priorities shall apply are defined in [4]. UE specific priorities shall be cleared when the validity time of the UE specific priorities expires, or when a PLMN selection is performed on request by NAS. UE specific priorities are not applied in camped on any cell state.

When the UE in camped normally state, has only dedicated priorities other than for the current frequency, the UE shall consider the current frequency to be the lowest priority frequency (i.e. lower than any of network configured values).

The UE shall inherit the priorities provided by dedicated signalling and the remaining validity time (i.e., T320 in E-UTRA, T322 in UTRA and T3230 in GERAN), if configured, at inter-RAT cell (re)selection.

The following definitions apply for the layers for which Thresh_x,high2 or Thresh_x,low2 are not provided:

– Criterion 1: the Srxlev_{nonServingCell,x} of a cell on an evaluated higher absolute priority layer is greater than Thresh_x,high during a time interval Treselection;

– Criterion 2: (Srxlev_ServingCell < Thresh_serving,low or Squal_ServingCell < = Thresh_serving,low2) and the Srxlev_{nonServingCell,x} of a inter-frequency cell on an evaluated equal absolute priority layer is greater than Thresh_x,low during a time interval Treselection;

– Criterion 3: (Srxlev_ServingCell < Thresh_serving,low or Squal_ServingCell <= Thresh_serving,low2) and the Srxlev_{nonServingCell,x} of a cell on an evaluated lower absolute priority layer is greater than Thresh_x,low during a time interval Treselection;

The following definitions apply for the layers for which both Thresh_x,high2 and Thresh_x,low2 are provided:

– Criterion 4: the Squal_{nonServingCell,x} of a cell on an evaluated higher absolute priority layer is greater than Thresh_x,high2 during a time interval Treselection;

– Criterion 5: for FDD, (Srxlev_ServingCell < =Thresh_serving,low or Squal_ServingCell < Thresh_serving,low2) and the Squal_{nonServingCell,x} of a cell on an evaluated lower absolute priority layer is greater than Thresh_x,low2during a time interval Treselection; for 1.28 Mcps TDD, (Srxlev_ServingCell < Thresh_serving,low) and the Squal_{nonServingCell,x} of a cell on an evaluated lower absolute priority layer is greater than Thresh_x,low2during a time interval Treselection;

Cell reselection to a cell on a higher absolute priority layer than the camped frequency shall be performed if criterion 1 or 4 is fulfilled.

Cell reselection to an inter-frequency cell on an equal absolute priority layer to the camped frequency shall be performed if criterion 2 is fulfilled.

Cell reselection to a cell on a lower absolute priority layer than the camped frequency shall be performed if criterion 3 or 5 is fulfilled.

If more than one cell meets the above criteria, the UE shall reselect the cell with the highest Srxlev_{nonServingCell,x} among the cells meeting the criteria on the highest absolute priority layer.

The UE shall not perform cell reselection to cells for which the cell selection criterion S is not fulfilled.

The UE shall not perform cell reselection until more than 1 second has elapsed since the UE camped on the current serving cell.

The UE shall not consider any exclude-listed cells as candidate for cell reselection to E-UTRA.

In CELL_FACH state, the UE shall not perform cell reselection to E-UTRA when E-UTRA measurement for CELL_FACH is configured. Except in the case that the cell reselection is to an E-UTRA CSG member cell, in this case cell reselection is performed as defined in [18].

The UE should not perform cell reselection while the UE has an allocated common E-DCH resource.

For UE in RRC connected mode states CELL_PCH or URA_PCH the interval Treselection_s,PCH applies, if provided in SIB4 (see [4]), while for UE in RRC connected mode state CELL_FACH the interval Treselection_s,FACH applies, if provided in SIB4 (see [4]).

In all the above criteria the values of Treselection_s, Treselection_s,PCH or Treselection_s,FACH apply for Treselection and are scaled according to the UE mobility state, as specified in 5.2.6.1.1a. For UTRA cells apply the scaling rules in 5.2.6.1.4. For GSM cells apply the scaling rules in 5.2.6.1.4 if "GSM ScalingFactor for Treselection" is not sent on system information, else follow the rules below for GSM. For EUTRA cells apply the scaling rules in 5.2.6.1.4 if "E-UTRA ScalingFactor for Treselection" is not sent on system information, else follow the rules below for EUTRA.

– The UE shall apply the following scaling rules to Treselection_s or Treselection_s,PCH or Treselection_s,FACH:

– For inter-RAT cells and high-mobility state not detected:

– for GERAN cells multiply Treselection_s or Treselection_s,PCH or Treselection_s,FACH by the IE "GSM ScalingFactor for Treselection" if sent on system information.

– for EUTRA cells multiply Treselection_s or Treselection_s,PCH or Treselection_s,FACH by the IE "E-UTRA ScalingFactor for Treselection" if sent on system information.

– For inter-RAT cells and high-mobility state is detected:

– for GERAN cells multiply Treselection_s or Treselection_s,PCH or Treselection_s,FACH by both the IEs "Speed dependent ScalingFactor for Treselection" if sent on system information and "GSM ScalingFactor for Treselection" if sent on system information.

– for EUTRA cells multiply Treselection_s or Treselection_s,PCH or Treselection_s,FACH by both the IEs "Speed dependent ScalingFactor for Treselection" if sent on system information and "E-UTRA ScalingFactor for Treselection" if sent on system information.

Cell reselection from UTRAN to E-UTRAN, for which Squal (RSRQ) based cell reselection parameters are broadcast in system information, shall be performed based on the Squal criteria (criterion 4 or 5) if the UE supports Squal based cell reselection from E-UTRAN to UTRAN. Otherwise, cell reselection to E-UTRAN shall be performed based on Srxlev criteria.

5.2.6.1.5 Cell reselection parameters in system information broadcasts

The selection of values for network controlled parameters can be optimised by means of different methods. Examples of methods are described in [6]. Cell reselection parameters are broadcast in system information and are read in the serving cell as follows:

Qoffset1_s,n

This specifies the offsetbetween the two cells. It is used for TDD and GSM cells and for FDD cells in case the quality measure for cell selection and re-selection is set to CPICH RSCP.

Qoffset2_s,n

This specifies the offsetbetween the two cells. It is used for FDD cells in case the quality measure for cell selection and re-selection is set to CPICH Ec/No.

Qhyst1_s

This specifies the hysteresis value (Qhyst). It is used for TDD and GSM cells and for FDD cells in case the quality measure for cell selection and re-selection is set to CPICH RSCP.

Qhyst1_s,PCH

This specifies the hysteresis value (Qhyst) to be used in RRC connected mode states CELL_PCH and URA_PCH. It is used for TDD and GSM cells and for FDD cells in case the quality measure for cell selection and re-selection is set to CPICH RSCP. If this parameter is not provided in SIB4, Qhyst1_s shall be used.

Qhyst1_s,FACH

This specifies the hysteresis value (Qhyst) to be used in RRC connected mode state CELL_FACH. It is used for TDD and GSM cells and for FDD cells in case the quality measure for cell selection and re-selection is set to CPICH RSCP. If this parameter is not provided in SIB4, Qhyst1_s shall be used.

Qhyst2_s

This specifies the hysteresis value (Qhyst). It is used for FDD cells if the quality measure for cell selection and re-selection is set to CPICH Ec/No.

Qhyst2_s,PCH

This specifies the hysteresis value (Qhyst) to be used in RRC connected mode states CELL_PCH and URA_PCH. It is used for FDD cells if the quality measure for cell selection and re-selection is set to CPICH Ec/No. If this parameter is not provided in SIB4, Qhyst2_s shall be used.

Qhyst2_s,FACH

This specifies the hysteresis value (Qhyst) to be used in RRC connected mode state CELL_FACH. It is used for FDD cells if the quality measure for cell selection and re-selection is set to CPICH Ec/No. If this parameter is not provided in SIB4, Qhyst2_s shall be used.

HCS_PRIO_s, HCS_PRIO_n

This specifies the HCS priority level (0-7) for serving cell and neighbouring cells.

HCS priority level 0 means lowest priority and HCS priority level 7 means highest priority.

HCS_OFF_mbms

This specifies the offset to the normal HCS priority level that is used for cells belonging to the MBMS PL.

Qhcs_s, Qhcs_n

This specifies the quality threshold levels for applying prioritised hierarchical cell re-selection.

Qoffmbms

This specifies the additional offset added to cells belonging to the MBMS PL.

Qoffset_temp

This specifies the additional offset to be used for cell selection and re-selection. It is temporarily used for FDD cells in case the RRC Connection Establishment fails on the cell as specified in [4].

Qqualmin

This specifies the minimum required quality level in the cell in dB. It is not applicable for TDD cells or GSM cells.

Qrxlevmin

This specifies the minimum required RX level in the cell in dBm.

PENALTY_TIME_n

This specifies the time duration for which the TEMPORARY_OFFSET_n is applied for a neighbouring cell.

TEMPORARY_OFFSET1_n

This specifies the offset applied to the H and R criteria for a neighbouring cell for the duration of PENALTY_TIME_n. It is used for TDD and GSM cells and for FDD cells in case the quality measure for cell selection and re-selection is set to CPICH RSCP.

TEMPORARY_OFFSET2_n

This specifies the offset applied to the H and R criteria for a neighbouring cell for the duration of PENALTY_TIME_n. It is used for FDD cells in case the quality measure for cell selection and re-selection is set to CPICH Ec/No.

T_CRmax

This specifies the duration for evaluating allowed amount of cell reselection(s).

N_CR

This specifies the maximum number of cell reselections.

T_CRmaxHyst

This specifies the additional time period before the UE can exit high-mobility.

non-HCS_T_CRmax

This specifies the duration for evaluating allowed amount of cell reselection(s) in case of non-HCS usage.

non-HCS_N_CR

This specifies the maximum number of cell reselections in case of non-HCS usage.

non-HCS_T_CRmaxHyst

This specifies the additional time period before the UE can revert to low-mobility measurements in case of non-HCS usage.

Treselection_s

This specifies the cell reselection timer value.

Treselection_s,PCH

This specifies the cell reselection timer value the UE shall use in RRC connected mode states CELL_PCH and URA_PCH if provided in SIB4, otherwise Treselection_s shall be used.

Treselection_s,FACH

This specifies the cell reselection timer value the UE shall use in RRC connected mode state CELL_FACH if provided in SIB4, otherwise Treselection_s shall be used.

Squal_ServingCell

This is the Squal value of the serving cell.

Ssearch_HCS

This threshold is used in the measurement rules for cell re-selection. When HCS is used, it specifies the limit for Srxlev in the serving cell below which the UE shall initiate measurements of all neighbouring cells of the serving cell. When HCS is not used, it specifies the limit for Srxlev in the serving cell below which the UE ranks inter-frequency neighbouring cells of the serving cell.

Ssearch_{RAT 1} – Ssearch_{RAT k}

This specifies the RAT specific threshold in the serving cell used in the inter-RAT measurement rules.

S_HCS,RATm

This threshold is used in the measurement rules for cell re-selection. When HCS is used, it specifies the RAT specific threshold in the serving cell used in the inter-RAT measurement rules. When HCS is not used, it specifies the limit for Srxlev in the serving cell below which the UE ranks inter-RAT neighbouring cells of the serving cell.

S_intrasearch

This specifies the threshold (in dB) for intra frequency measurements and for the HCS measurement rules.

S_intersearch

This specifies the threshold (in dB) for inter-frequency measurements and for the HCS measurement rules.

S_{limit,SearchRATm}

This threshold is used in the measurement rules for cell re-selection when HCS is used. It specifies the RAT specific threshold (in dB) in the serving UTRA cell above which the UE may choose to not perform any inter-RAT measurements in RAT "m".

Srxlev_{nonServingCell,x}

This is the Srxlev value of an evaluated neighbour cell on an absolute priority layer.

Srxlev_ServingCell

This is the Srxlev value of the serving cell.

S_{prioritysearch1}

This threshold is used in the measurement rules for cell re-selection when absolute priorities are used. It specifies the value of Srxlev in the serving cell controlling the rate of inter-frequency and inter-RAT measurements.

S_{prioritysearch2}

This threshold is used in the measurement rules for cell re-selection when absolute priorities are used. It specifies the value of Squal in the serving cell controlling the rate of inter-frequency and inter-RAT measurements.

Speed dependent ScalingFactor for Treselection

This specifies the scaling (multiplication) factor to be used by the UE in idle mode or RRC connected mode states for the parameters Treselection_s or Treselection_s,PCH or Treselection_s,FACH in case high-mobility state has been detected.

Inter-frequency ScalingFactor for Treselection

This specifies the scaling (multiplication) factor to be used by the UE for scaling the parameters Treselection_s or Treselection_s,PCH or Treselection_s,FACH for the inter-frequency case.

Inter-RAT ScalingFactor for Treselection

This specifies the scaling (multiplication) factor to be used by the UE for scaling the parameters Treselection_sor Treselection_s,PCH or Treselection_s,FACH for the inter-RAT case.

GSM ScalingFactor for Treselection

This specifies the scaling (multiplication) factor to be used by the UE for scaling the parameters Treselection_sor Treselection_s,PCH or Treselection_s,FACH for the GSM case. This scaling is only applicable at absolute priority based criteria for cell reselection to GSM.

E-UTRA ScalingFactor for Treselection

This specifies the scaling (multiplication) factor to be used by the UE for scaling the parameters Treselection_sor Treselection_s,PCH or Treselection_s,FACH for the EUTRA case. This scaling is only applicable at absolute priority based criteria for cell reselection to EUTRA.

Thresh_x,high

A Srxlev based threshold used by the UE for cell reselection towards a higher absolute priority layer when absolute priorities are applied. A threshold is defined for each absolute priority layer.

Thresh_x,high2

A Squal based threshold used by the UE for cell reselection towards a higher absolute priority layer when absolute priorities are applied. A threshold is defined for each absolute priority layer.

Thresh_x,low

A Srxlev based threshold used by the UE for cell reselection towards an equal or lower absolute priority layer when absolute priorities are applied. A threshold is defined for each absolute priority layer.

Thresh_x,low2

A Squal based threshold used by the UE for cell reselection towards a lower absolute priority layer when absolute priorities are applied. A threshold is defined for each absolute priority layer.

Thresh_serving,low

This threshold is used in the rules for cell reselection when absolute priorities are used. It specifies the limit for Srxlev in the serving cell below which the UE may perform cell reselection to a cell on an equal or lower absolute priority layer.

Thresh_serving,low2

This threshold is used in the rules for cell reselection when absolute priorities are used. It specifies the limit for Squal in the serving cell below which the UE may perform cell reselection to a cell on an equal or lower absolute priority layer.

Dedicated CSG frequency

This specifies a frequency which is used for CSG deployment only.

5.2.6.2 GSM case

The cell reselection procedure in GSM, including reselection from GSM to UTRA, is specified in [1].

5.2.6.3 E-UTRA case

The cell reselection procedure in E-UTRA, including inter-RATs reselection, is specified in [18].

5.2.6.4 Cell reselection with CSG cells

5.2.6.4.1 Cell reselection from a non-CSG cell to a CSG cell

In addition to normal cell reselection, the UE shall use an autonomous search function to detect at least previously visited CSG member cells on serving frequency, non serving frequencies and inter-RAT frequencies, according to the performance requirements specified in [10], when at least one CSG with associated PLMN identity ID is included in the UE’s Permitted CSG list. The UE is required to perform autonomous search function in Idle, Cell_PCH, URA_PCH and CELL_FACH states. For CELL_FACH, the autonomous search function for reselection to non-serving frequencies and inter-RAT frequencies needs only to be performed when second DRX is used. The UE shall disable the autonomous search function for CSG cells if the UE’s Permitted CSG list is empty. If "Dedicated CSG frequency(ies) " IE is present, the UE may use the autonomous search function only on these dedicated frequencies and on the other frequencies listed in the system information.

NOTE: The UE autonomous search function, per UE implementation, determines when and/or where to search for CSG member cells.

When the UE has no or an empty Permitted CSG list, the UE may ignore cells with PSC in the stored range "CSG PSC Split Information" [4] reserved for CSG cells for intra-frequency and inter-frequency measurements and cell re-selections.

If the UE detects a suitable CSG cell on the same frequency it shall reselect this cell if the concerned CSG cell is the highest ranked cell, according to 5.2.6.1.4.

If the UE detects a suitable CSG cell on a different frequency it shall reselect this cell irrespective of the cell reselection rules applicable for the cell the UE is currently camped on, if the detected suitable CSG cell is the strongest cell on that frequency. If suitable CSG cells are detected on different frequencies and these are the strongest cells on their frequencies, then the UE shall reselect to any one of them.

If the UE detects one or more suitable CSG cell on another RAT, the UE shall reselect to one of them according to [18].

5.2.6.4.2 Cell reselection from a CSG cell to non-CSG cell

While camped on a suitable CSG cell, the UE shall consider the frequency of the serving cell to be the highest priority frequency (i.e. higher than any of network configured values or highest HCS priority) and shall not reselect to non-CSG cell as long as the serving cell remains the highest ranked cell on that frequency (This includes the case when the UE has only dedicated priorities for other frequencies but not for the current frequency, i.e. the UE does not consider the current frequency to be the lowest priority frequency according to rules in 5.2.6.1.2a and 5.2.6.1.4a). Cell reselection rules as defined in section 5.2.6.1 are applied for cell reselection from a CSG cell to non-CSG cell.

5.2.6.4.3 Cell reselection from a CSG cell to a CSG cell

To search for CSG cells not listed in the system information of the serving CSG cell, the UE may use the autonomous search function when at least one CSG ID with associated PLMN identity is included in the UE’s Permitted CSG list. The UE is required to perform autonomous search function in Idle, Cell_PCH, URA_PCH and CELL_FACH states. For CELL_FACH, the autonomous search function for reselection to non-serving frequencies and inter-RAT frequencies needs only to be performed when second DRX is used. If "Dedicated CSG frequency(ies)" IE is present, the UE may use the autonomous search function only on dedicated frequencies and on other frequencies listed in the system information.

If the UE detects a suitable CSG cell on the same frequency, it shall reselect to this cell if the concerned CSG cell is the highest ranked cell, according to 5.2.6.1.4.

While camped on a suitable CSG cell, the UE shall consider the frequency of the serving cell to be the highest priority frequency (i.e. higher than any of network configured values or highest HCS priority) as long as the serving cell is the highest ranked cell on that frequency (This includes the case when the UE has only dedicated priorities for other frequencies but not for the current frequency, i.e. the UE does not consider the current frequency to be the lowest priority frequency according to rules in 5.2.6.1.2a and 5.2.6.1.4a).

If the UE detects one or more suitable CSG cell on another RAT, the UE may reselect to one of them according to [18].

For reselection to neighbour CSG cells listed in the system information of the serving CSG cell the UE shall apply cell measurement rules according to 5.2.6. If the UE detects a suitable CSG cell that is listed in the system information of the serving cell on other frequencies, and the detected CSG cell is the strongest cell on that frequency, then the UE shall consider these frequencies to have a priority equal to the current frequency and shall follow cell reselection rules according to 5.2.6.1.4 and 5.2.6.1.4a.

5.2.6.5 Cell Reselection with Hybrid Cells

In addition to normal cell reselection rules, the UE shall use an autonomous search function to detect at least previously visited hybrid cells whose CSG ID and associated PLMN identity is in the UE’s Permitted CSG list according to the performance requirements specified in [10]. The UE shall treat detected hybrid cells as CSG cells if the CSG ID and any of the broadcasted PLMN identity of the hybrid cell is in the UE’s Permitted CSG list and as normal cells otherwise.

5.2.7 Cell Selection when leaving connected mode

5.2.7.1 UTRA case

When returning to idle mode from connected mode, the UE shall select a suitable cell to camp on. Candidate cells for this selection are the cell(s) used immediately before leaving connected mode. If no suitable cell is found, the UE shall use the Stored information cell selection procedure in order to find a suitable cell to camp on.

When returning to idle mode after an emergency call on any PLMN, the UE shall select an acceptable cell to camp on. Candidate cells for this selection are the cell(s) used immediately before leaving connected mode. If no acceptable cell is found, the UE shall continue to search for an acceptable cell of any PLMN in state Any cell selection.

5.2.7.2 GSM case

Cell selection when leaving connected mode in GSM is specified in [1].

5.2.7.3 E-UTRA case

Cell selection when leaving connected mode in E-UTRA is specified in [18].

5.2.8 Any Cell Selection state

In this state, the UE shall attempt to find an acceptable cell of an any PLMN to camp on, trying all RATs that are supported by the UE and searching first for a high quality cell, as defined in subclause 5.1.2.2.

The UE, which is not camped on any cell, shall stay in this state until an acceptable cell is found.

5.2.9 Camped on Any Cell State

5.2.9.1 UTRA case

In this state, the UE shall perform the following tasks:

– select and monitor the indicated PICH and PCH of the cell as specified in clause 8;

– monitor relevant System Information; This is specified in [4];

– perform necessary measurements for the cell reselection evaluation procedure;

– Execute the cell reselection evaluation process on the following occasions/triggers:

1) UE internal triggers, so as to meet performance as specified in [10] and [11];

2) When information on the BCCH used for the cell reselection evaluation procedure has been modified;

– regularly attempt to find a suitable cell trying all RATs that are supported by the UE. If a suitable cell is found, this causes an exit to number 2 in Figure 2.

In this state the UE is not permitted to receive any MBMS services.

5.2.9.2 GSM case

The camped on any cell state in GSM is specified in [1].

5.2.9.3 E-UTRA case

The camped on any cell state in E-UTRA is specified in [18].

5.3 Cell Reservations and Access Restrictions (cells not operating in MBSFN mode)

5.3.1 UTRA cells

There are two mechanisms which allow an operator to impose cell reservations or access restrictions. The first mechanism uses indication of cell status and special reservations for control of cell selection and re-selection procedures. The second mechanism, referred to as Access Control, shall allow to prevent selected classes of users from sending initial access messages for load control reasons. At subscription, one or more Access Classes are allocated to the subscriber and stored in the USIM [9], which are employed for this purpose.

5.3.1.1 Cell status and cell reservations

Cell status and cell reservations are indicated with the Cell Access Restriction Information Element in the System Information Message [4] by means of four Information Elements:

– Cell barred (IE type: "barred" or "not barred"),

– Cell Reserved for operator use (IE type: "reserved" or "not reserved"),

– Cell reserved for future extension (IE type: "reserved" or "not reserved").

– Cell reserved for CSG (IE type: "true" or not present).

When cell status is indicated as "not barred", "not reserved" for operator use and "not reserved" for future extension (Cell Reservation Extension),

– All UEs shall treat this cell as candidate during the cell selection and cell re-selection procedures in Idle mode and in Connected mode.

When cell status is indicated as "not barred", "not reserved" for operator use and "reserved" for future extension (Cell Reservation Extension),

– If Cell Reserved for CSG is indicated then CSG capable UEs shall behave as if cell status is indicated as "not reserved" for future extension (Cell Reservation Extension).

– If Cell Reserved for CSG is not indicated then UEs shall behave as if cell status "barred" is indicated using the value "not allowed" in the IE "Intra-frequency cell re-selection indicator" and the maximum value for T_barred, see [4] (see also below).

When cell status is indicated as "not barred" and "reserved" for operator use,

– If the UE is assigned an Access Class 11 or 15 and if the cell belongs to the home PLMN or to any EHPLMN:

– the UE shall treat this cell as candidate during the cell selection and cell re-selection procedures in Idle mode and in Connected mode.

– else:

– UEs shall behave as if cell status "barred" is indicated using the value "not allowed" in the IE "Intra-frequency cell re-selection indicator" and the maximum value for T_barred, see [4] (see also below).

When cell status "barred" is indicated,

– The UE is not permitted to select/re-select this cell, not even for emergency calls.

– The UE shall ignore the "Cell Reserved for future extension (Cell Reservation Extension) use" IE.

– The UE is not permitted to receive any MBMS services.

– The UE shall select another cell according to the following rule:

– If the "Intra-frequency cell re-selection indicator" IE in Cell Access Restriction IE is set to value "allowed", the UE may select another cell on the same frequency if selection/re-selection criteria are fulfilled.

– If the UE is camping on another cell, the UE shall exclude the barred cell from the neighbouring cell list until the expiry of a time interval T_barred. The time interval T_barred is sent via system information in a barred cell together with Cell status information in the Cell Access Restriction IE.

– If the UE does not select another cell, and the barred cell remains to be the "best" one, the UE shall after expiry of the time interval T_barred again check whether the status of the barred cell has changed.

– If the "Intra-frequency cell re-selection indicator" IE is set to "not allowed" the UE shall not re-select a cell on the same frequency as the barred cell. During an ongoing emergency call, the Intra-frequency cell re-selection indicator IE" shall be ignored, i.e. even if it is set to "not allowed" the UE may select another intra-frequency cell.

– If the barred cell remains to be the "best" one, the UE shall after expiry of the time interval T_barred again check whether the status of the barred cell has changed.

If the "Intra-frequency cell re-selection indicator" IE has been read from a CSG cell it shall be ignored by the UE and the UE is allowed to reselect another cell on the same frequency if the cell reselection criteria are fulfilled.

The reselection to another cell may also include a change of RAT.

5.3.1.2 Access Control

Information on cell access restrictions associated with the Access Classes and ACDC are broadcast as system information, [4].

The UE shall ignore Access Class related cell access restrictions when selecting a cell to camp on, i.e. it shall not reject a cell for camping on because access on that cell is not allowed for any of the Access Classes of the UE. A change of the indicated access restriction shall not trigger cell re-selection by the UE.

Access Class related cell access restrictions shall be checked by the UE before sending an RRC connection request message when entering Connected Mode from UTRAN Idle mode. Access Class related cell access restrictions, if it is sent as a part of Domain Specific Access Restriction parameters, shall also be checked by the UE before sending INITIAL DIRECT TRANSFER message. Access Class related cell access restrictions, if it is sent as a part of Paging Permission with Access Control Parameters, shall be checked by the UE before sending a response to Paging message or before initiating a Location/Registration procedure. Access Class related cell access restrictions, if it is sent as a part of Extended Access Barring parameters, shall be checked by the UE before sending an RRC connection request message or INITIAL DIRECT TRANSFER message subject to extended access barring as indicated by higher layers. Otherwise, cell access restrictions associated with the Access Classes shall not apply for a UE which already is in Connected Mode.

For Access Class 0 to 9, ACDC related cell access restrictions, if it is sent in ACDC Barring Information paramerers shall be checked by the UE before sending an RRC connection request message when entering Connected Mode from UTRAN Idle mode in PS domain.

5.3.1.3 Emergency Call

A restriction on emergency calls, if needed, shall be indicated in the "Access class barred list" IE [4]. If access class 10 is indicated as barred in a cell, UEs with access class 0 to 9 or without an IMSI are not allowed to initiate emergency calls in this cell. For UEs with access classes 11 to 15, emergency calls are not allowed if both access class 10 and the relevant access class (11 to 15) are barred. Otherwise, emergency calls are allowed for those UEs.

Full details of operation under "Access class barred list" are described in [9].

5.3.2 GSM cells

The cell access restrictions applicable to GSM are specified in [1].

5.3.3 E-UTRA cells

The cell access restrictions applicable to E-UTRA are specified in [18].

5.3a Cell Reservations and Access Restrictions (MBSFN cells only for FDD, 3.84 Mcps TDD IMB and 3.84/7.68 Mcps TDD)

For an MBSFN cluster (see [4]) when cell status is indicated "not reserved" for operator use and "not reserved" for future extension (Cell Reservation Extension), and Cell Barred is set to "barred" or "not barred",

– All UEs shall treat this MBSFN cluster as a candidate during the MBSFN cluster selection and MBSFN cluster re-selection procedures.

For an MBSFN cluster (see [4]) when cell status is indicated as "not reserved" for operator use and "reserved" for future extension (Cell Reservation Extension),

– UEs shall not consider this MBSFN cluster as a candidate during the MBSFN cluster selection and MBSFN cluster re-selection procedures. The UE may choose to not recheck the status of this MBSFN cluster during the time corresponding to the maximum value for T_barred (see [4]).

For an MBSFN cluster (see [4]) when cell status is indicated as "reserved" for operator use,

– if a UE is assigned to Access Class 11 or 15 and the MBSFN cluster belongs to the home PLMN or to any EHPLMN:

– the UE shall treat this MBSFN cluster as a candidate during the MBSFN cluster selection and MBSFN cluster re-selection procedures.

– else:

– UEs shall not consider this MBSFN cluster as candidate during the MBSFN cluster selection and MBSFN cluster re-selection procedures The UE may choose to not recheck the status of this MBSFN cluster during the time corresponding to the maximum value for T_barred (see [4]).

NOTE: The UE should in all cases assume "intra-frequency cell re-selection" has the value "allowed".

5.4 Cell Selection and Reselection Processes in RRC Connected Mode

5.4.1 Void

5.4.2 Void

5.4.3 Cell Reselection Process in RRC connected mode

The cell reselection process in Connected Mode is the same as cell reselection evaluation process used for idle mode, described in subclause 5.2.6.

5.4.4 Cell Selection Process in RRC connected mode

The cell selection process in Connected Mode is for ‘out of service’ conditions [4] is the same as the cell selection process used for idle mode, described in subclause 5.2.3.

Selection of a suitable cell during a state transition or a change of frequency in Connected Mode is the same as the selection of a suitable UTRA cell used for idle mode, described in subclause 5.2.3.1. If the UE is ordered to select a suitable UTRA cell on a given frequency, it shall attempt to select a suitable cell on that frequency before considering cells on other frequencies.

5.5 Location Registration

In the UE, the AS shall report registration area information to the NAS.

If the UE reads more than one PLMN identity in the current cell, the UE shall report the found PLMN identities that make the cell suitable in the registration area information to NAS.

The non-access part of the location registration process is specified in [5].

Actions for the UE AS upon reception of Location Registration reject are specified in [9] and [16].

5.6 Support for manual CSG Selection

5.6.1 UTRA case

In the UE on request of NAS, the AS shall scan all RF channels in the UTRA bands according to its capabilities to find available CSGs. On each carrier, the UE shall at least search for the strongest cell, read its system information and report available CSG ID(s) together with their "HNB name" (if broadcast) and PLMN(s) to the NAS. The search for available CSGs may be stopped on request of the NAS.

If NAS has selected a CSG and provided this selection to AS, the UE shall search for an acceptable or suitable cell belonging to the selected CSG to camp on.

5.6.2 E-UTRA case

Support for manual CSG selection in E-UTRA is described in [18].

5.7 Logged Measurements

The UE may be configured to perform logging of measurement results in idle mode, CELL_PCH, URA_PCH states and CELL_FACH state when second DRX cycle is used with LOGGING MEASUREMENT CONFIGURATION message specified in TS 25.331 [4]. This configuration is valid while the logging duration timer is running.

If the configuration of logged measurements is valid, the UE shall perform logging of measurement results if all of the following conditions are met:

– the UE is in camped normally state in idle mode, CELL_PCH or URA_PCH states or CELL_FACH state when second DRX cycle is used;

– the RPLMN of the UE is present in the MDT PLMN identity list, if received in the LOGGING MEASUREMENT CONFIGURATION message, or the RPLMN of the UE is the same as the RPLMN at the point of time of LOGGING MEASUREMENT CONFIGURATION message reception;

– the UE is camped on a cell belonging to Area Configuration (see TS 25.331 [4]), if configured;

– the UE is camped on the RAT where the logged measurement configuration was received.

Otherwise, the logging of measurement results shall be suspended.

NOTE: Even if logging of measurement results is suspended, the logging duration timer and time stamp will continue, and the logged measurement configuration and corresponding log are kept.

5.8 Logged UTRAN ANR

5.8.1 General

The UE may be configured to perform UTRAN ANR measurement and logging in IDLE mode, CELL_PCH, URA_PCH state and CELL_FACH state when second DRX cycle is used with Logging Measurement Configuration message as specified in [4]. If configured, the UE will

– perform measurements and evaluation on the cells which are not included in the neighbour cell list in IDLE mode, CELL_PCH, URA_PCH state and CELL_FACH state when second DRX cycle is used.

– log information of the detected cells meeting the logging rules as specified in [4].

5.8.2 UTRAN ANR measurement process

5.8.2.1 Intra-freq and inter-freq ANR case

If configured via the Logging Measurement Configuration message, the UE may perform intra-freq and inter-freq ANR measurements and logging only when:

– in IDLE mode, CELL_PCH, URA_PCH state and CELL_FACH state when second DRX cycle is used.

– the UE is camping normally on a UTRAN cell belonging to the PLMN or the list of Equivalent PLMNs where the Logging Measurement Configuration is received.

During the intra-freq and inter-freq ANR process, the UE may measure on the frequencies associated with the cells listed in the neighbour cell list and log corresponding information of the detected set cells as specified in TS 25.331 [4].

5.8.2.2 Inter-RAT ANR case

If configured to perform inter-RAT ANR via the Logging Measurement Configuration message, the UE may perform inter-RAT ANR logging only when:

– after inter-RAT cell reselection from E-UTRAN or GSM to a normal UTRAN cell belonging to the PLMN or the list of Equivalent PLMNs where the Logging Measurement Configuration is received.

During the inter-RAT ANR process, the UE may log the corresponding information of the previously camped E-UTRAN or GSM cell as specified in TS 25.331 [4].

5.9 Accessibility measurements

The UE logs failure information when the RRC connection establishment procedure fails as specified in TS 25.331 [4].

5.10 RAN-assisted WLAN interworking

The purpose of this procedure is to facilitate RAN-assisted WLAN interworking.

5.10.1 RAN assistance parameter handling in Idle mode, CELL_PCH, URA_PCH and CELL_FACH

UEs in idle mode or in CELL_FACH, CELL_PCH or URA_PCH state shall store and apply RAN assistance parameters for the rules in sub-clause 5.10.2 as defined in the following:

– RAN assistance parameters received in System information block type 23 are used only if the UE is in camped normally state;

– upon cell reselection, and cell selection to another cell than the serving cell (or the best cell in case of UEs previously in CELL_DCH state and configured with DCHs only), the UE shall discard the RAN assistance parameters received in the UTRAN MOBILITY INFORMATION message or in the CELL UPDATE CONFIRM message and apply the RAN assistance parameters received in System information block type 23.

5.10.2 Access network selection and traffic steering rules

The rules in this sub-clause are only applicable for WLANs for which identifiers have been signaled to the UE by UTRAN and the UE is capable of access network selection and traffic steering rules. Coexistence with ANDSF based WLAN selection and traffic steering methods on the UE is based on mechanism described in TS 23.402 [23]. The rules refer to the following WLAN quantities:

ChannelUtilizationWLAN	WLAN channel utilization as defined in sub-clause 8.4.2.30 in [24].
BackhaulRateDlWLAN	WLAN DLBandwidth as defined in sub-clause 9.1.2 in [25].
BackhaulRateUlWLAN	WLAN ULBandwidth as defined sub-clause 9.1.2 in in [25].
BeaconRSSI	WLAN Beacon RSSI as defined in [26] and [27].

The upper layers in the UE shall be notified (see TS 24.302 [28]) when and for which WLAN(s), that matches all the provided identifiers (in sub-clause 5.10.3) for a specific entry in the list, the following conditions 1 and 2 for steering traffic from UTRAN to WLAN are satisfied for a time interval Tsteering_WLAN:

1) In the UTRAN serving cell:

Qrxlevmeas < Thresh_{ServingOffloadWLAN, Low}; or

Qqualmeas < Thresh_{ServingOffloadWLAN, Low2}.

2) In the target WLAN:

ChannelUtilizationWLAN < Thresh_{ChUtilWLAN, Low}; and

BackhaulRateDlWLAN > Thresh_{BackhRateDLWLAN, High}; and

BackhaulRateUlWLAN > Thresh_{BackhRateULWLAN, High}; and

BeaconRSSI > Thresh_{BeaconRSSIWLAN, High}.

The UE shall not consider the metrics for which a threshold has not been provided. The UE shall evaluate the UTRAN conditions on the serving cell in Idle mode, URA_PCH, CELL_PCH, CELL_FACH and CELL_DCH. If not all metrics related to the provided thresholds can be acquired for a WLAN BSS, the UE shall exclude that WLAN BSS from the evaluation of the above rule.

The upper layers in the UE shall be notified (see TS 24.302 [28]) when the following conditions 3 or 4 for steering traffic from WLAN to UTRAN are satisfied for a time interval Tsteering_WLAN:

1) In the source WLAN:

ChannelUtilizationWLAN > Thresh_{ChUtilWLAN, High}; or

BackhaulRateDlWLAN < Thresh_{BackhRateDLWLAN, Low}; or

BackhaulRateUlWLAN < Thresh_{BackhRateULWLAN, Low};or

BeaconRSSI < Thresh_{BeaconRSSIWLAN, Low}.

2) In the target UTRANcell:

Qrxlevmeas > Thresh_{ServingOffloadWLAN, High}; and

Qqualmeas > Thresh_{ServingOffloadWLAN, High2}.

If the FDD UE is configured with DCH only, the reference cell to use, for the rules defined in this sub-clause, is the best cell in active set.

5.10.3 RAN assistance parameters definition

The following RAN assistance parameters for RAN-assisted WLAN interworking may be provided:

Thresh_{ServingOffloadWLAN, Low}

This specifies the CPICH RSCP for FDD cells (dBm) and P-CCPCH RSCP for TDD cells (dBm) used by the UE for traffic steering from UTRAN to WLAN.

Thresh_{ServingOffloadWLAN, High}

This specifies the CPICH RSCP for FDD cells (dBm) and P-CCPCH RSCP for TDD cells (dBm) used by the UE for traffic steering from WLAN to UTRAN.

Thresh_{ServingOffloadWLAN, Low2}

This specifies the CPICH Ec/N0 (dB) for FDD cells used by the UE for traffic steering from UTRAN to WLAN.

Thresh_{ServingOffloadWLAN, High2}

This specifies the CPICH Ec/N0 (dB) for FDD cells used by the UE for traffic steering from WLAN to UTRAN.

Thresh_{ChUtilWLAN, Low}

This specifies the WLAN channel utilization (BSS load) threshold used by the UE for traffic steering from UTRAN to WLAN.

Thresh_{ChUtilWLAN, High}

This specifies the WLAN channel utilization (BSS load) threshold used by the UE for traffic steering from WLAN to UTRAN.

Thresh_{BackhRateDLWLAN, Low}

This specifies the backhaul available downlink bandwidth threshold used by the UE for traffic steering from WLAN to UTRAN.

Thresh_{BackhRateDLWLAN, High}

This specifies the backhaul available downlink bandwidth threshold used by the UE for traffic steering from UTRAN to WLAN.

Thresh_{BackhRateULWLAN, Low}

This specifies the backhaul available uplink bandwidth threshold used by the UE for traffic steering from WLAN to UTRAN.

Thresh_{BackhRateULWLAN, High}

This specifies the backhaul available uplink bandwidth threshold used by the UE for traffic steering from UTRAN to WLAN.

Thresh_{BeaconRSSIWLAN, Low}

This specifies the Beacon RSSI threshold used by the UE for traffic steering from WLAN to UTRAN.

Thresh_{BeaconRSSIWLAN, High}

This specifies the Beacon RSSI threshold used by the UE for traffic steering from UTRAN to WLAN.

Tsteering_WLAN

This specifies the timer value during which the rules should be fulfilled before starting traffic steering between UTRAN and WLAN.

WLAN identifiers

Only the SSIDs, BSSIDs and HESSIDs which are provided in this parameter shall be considered for traffic steering between UTRAN and WLAN based on the rules in this chapter.