fmln pdf

www.huawei.com

Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.

UE Behaviors in Idle Mode


ForewordSRAN UE behaviors in idle mode focus on:

PLMN selection

2G-3G cell reselection

3G-2G cell reselection

PLMN selectionUsed to ensure that the PLMN selected by the UE provides services properly. System information receptionThe network broadcasts the network information to the UE that camps on the cell. Upon reception of broadcast information, the UE obtains the network information and takes actions accordingly. Cell selection and reselectionUsed to ensure that the UE finds a suitable cell to camp on.


References3GPP TS 25.304: UE Procedures in Idle Mode and Procedures

for Cell Reselection in Connected Mode


ObjectivesUpon completion of this course, you will be able to:

Describe the working principles of the UE Behaviors in Idle

Mode feature

Perform parameters modification of the UE Behaviors in Idle

Mode feature


Contents1. PLMN selection and Cell selection

2. 2G-3G cell reselection



PLMN selection

For 2G-3G network, there are two kinds of PLMN

configuration:

2G and 3G configured as the same PLMN ID

2G and 3G PLMN is difference


Two Kinds of PLMN Solution Customized Solution

2G Network Version cannot support R99 and is difficult to upgrade

2G Network Version can support R99 or can be upgraded to R99.

Solution based on PLMN Selection3G PLMN ID different from 2G PLMN ID

HPLMN = 3G PLMN ID & Set HPLMN searching time

Solution based on Cell reselection3G PLMN ID same as 2G PLMN ID

Reselection triggered by configuration parameters

Different 2G version

For difference PLMN IDAdvantage: No change on 2G networkDisadvantage: Slowly roam from 2G to 3G

For Same PLMN ID:Advantage: Rapidly roam back to 3GDisadvantage: Need patch on 2G,Additional 2G Configuration

For Huawei mostly 2G equipment support R99, so recommendation is same PLMN ID


Cell SelectionAfter PLMN selection, UE will try to find a suitable cell to

stay, this behavior is cell selection.

If UE just supports 2G, so it will perform 2G cell selection

If UE just supports 3G, so it will perform 2G cell selection

If UE support 2G and 3G, depending on the UE setting: Prefer

2G; Prefer 3G, Auto


Cell SelectionIf UE support 2G and 3G, UE setting: Auto

SIM

2G service area

3G/2G service area2G

3G

If UE support 2G and 3G, also on the 2G and 3G coverage area, it will depend on SIM card. If you use sim card, 2G cell will be selected first.


Cell SelectionIf UE support 2G and 3G, UE setting: Auto

USIM

2G service area

3G/2G service area2G

3G

If UE support 2G and 3G, also on the 2G and 3G coverage area, it will depend on SIM card. If you use USIM card, 3G cell will be selected first.


Cell ReselectionThe signal strength of both serving cell and neighboring cells varies with the movement of a UE and so the UE needs to select the most suitable cell to camp on. This process is called cell reselection

For 2G/3G network, cell reselection should be bidirectional. Sometimes cell reselection also will be triggered to balance the 2G/3G traffic.

New system information will be adopted to support 2G/3G cell reselection.


System Information For 2G/3G GSM SI 2ter:

contains frequency of 3G neighbor cell

GSM SI 2quater:contains information of cell reselection and measurement report, such

as: Qsearch I, Measurement Report Type

GSM SI 3: contains sending WCDMA classmark information and indication of existence SI 2quater

WCDMA SIB 11: contains measurement controlling information for 3G/2G cell reselection


2G-3G Cell ReselectionFrequency of 3G neighbor cell, which is in the “UTRAN FDD

cell BA1” table, should be sent to UE via system information.

If just one frequency in the UTRAN FDD BA1 table, MS should implement cell reselection equal or less than 30S. One more 3G frequency, extra 30s needed.


2G-3G Cell ReselectionFor 2G-3G cell reselection, two modes should be

considered:

Cell reselection in the CS idle mode

Cell reselection in the PS mode


CS Idle Mode

If: 2G receiving level <Q_search_I （0 =<Qsearch_I <7）2G receiving level >Q_search_I （7 <Qsearch_I <15）Qsearch_I=7 (allways); Qsearch_I=15 (never)

WCDMA RSCP – 2G receiving level > FDD_OffsetAnd

WCDMA EcNo > FDD_Qmin

Start monitor 3G neighbor cell

Implement cell reselection to 3G


CS Idle ModeQsearch I

This parameter specifies the level threshold for cell reselection

in idle mode. In idle mode, if the signal level in the serving cell

is below [0, 7] or above [8, 15], the MS starts to search for 3G

cells.

Default Value:15

If this parameter is set to 5 and if the signal level of the serving cell is lower than 5, the MS starts to search for 3G cells.If this parameter is set to 10 and if the signal level of the serving cell is higher than 10, the MS starts to search for 3G cells.0: -98 dBm1: -94 dBm2: -90 dBm3: -86 dBm4: -82 dBm5: -78 dBm6: -74 dBm7：(always), that is, the MS keeps searching for 3G cells8: -78 dBm9: -74 dBm10: -70 dBm11: -66 dBm12: -62 dBm13: -58 dBm14: -54 dBm15：∞(never), that is, the MS does not search for 3G cells


CS Idle ModeFDD Q Offset

Only when the average receive level of a 3G cell is FDD Q Offset greater than that of the serving cell, the 3G cell becomes a candidate cell.

0: -∞ (always select a cell if acceptable)

1: -28 dB

2: -24 dB

…

15: 28 dB

Default Value:8


CS Idle ModeFDD Qmin

This parameter specifies one threshold of the signal level for

3G cell reselection. Only when the receive level of a 3G cell is

greater than FDD Qmin, the 3G cell can be one candidate cell

for cell reselection.

Default Value:0

For FDD Qmin, the according value as below:0: -20 dB1: -6 dB2: -18 dB3: -8 dB4: -16 dB5: -10 dB6: -14 dB7: -12 dB.


PS Mode

PBCCH existence

Qsearch_P level threshold

FDD_Offset and DD_Qmin are met

Always same as

Qsearch_I

PBCCH not existence

Qsearch_I level threshold

Implement cell reselection to 3G

For the 2G/3G PS cell reselection, it should be bidirectional.


2G-3G Cell ReselectionIf two times cell reselection less than 15S, FDD_Offset

should plus 5dB.

If UE reselection from 3G to 2G, at least the first 5S, this UE

couldn’t occur cell reselection back to 3G neighbor cells.

If more than one 3G neighbor cell is met all requirement, the

strongest one will be target cell.


Measurement Start Criteria Inter-RAT measurement:

Squal ≤ SsearchRATm

↓

Qqualmeas − Qqualmin ≤ SsearchRATm

↓

Qqualmeas ≤ Qqualmin + SsearchRATm

If Squal > SsearchRATm, the UE need not start the inter-RAT measurement.If Squal ≤ SsearchRATm, the UE need to start the inter-RAT measurement.If system messages do not contain SsearchRATm, the UE always need to start the inter-RAT measurement.If criteria is met, UE will start to measure the 2G neighbor cell.


Parameters of Measurement Start Criteria (Cont.)

SsearchRat

Parameter name: Inter-RAT cell reselection threshold

Recommended value: 127, namely none

SearchRatContent: A threshold for inter-RAT cell reselection. When the quality (CPICH Ec/No measured by UE) of the serving cell is lower than this threshold plus the [Qqualmin] of the cell, the inter-RAT cell reselection procedure will be started. This parameter is not configured when its value is 127.Value range: {{-16~10}, {127}} Physical value range: -32~20; step: 2Physical unit: dBSet this parameter through ADD UCELLSELRESEL, query it through LST UCELLSELRESEL, and modify it through MOD UCELLSELRESEL.


Measurement Start Criteria Description

The intra-frequency, inter-frequency, and inter-RAT measurement criteria are as shown in the above figure.The intra-frequency cell reselection has a priority higher than the inter-frequency cell reselection and inter-RAT cell reselection, the intra-frequency cell reselection start threshold should be higher than the inter-frequency cell reselection start threshold and inter-RAT cell reselection start threshold. If the cell reselection threshold is set to a comparatively high value, the UE may frequently start cell reselections, and the battery of the UE may be largely consumed. If the cell reselection threshold is set to a comparatively low value, it is difficult for cell reselections to be started, and the UE may not timely reside in the cells with good quality, affecting the quality of communication between the UTRAN and the UE. For detailed information, refer to 3GPP TS 25.304.

IdleSintrasearchParameter name: Intra-freq cell reselection threshold for idle mode Recommended value: 127, namely none

ConnSintrasearchParameter name: Intra-freq cell reselection threshold for connected mode Recommended value: 127, namely none

IdleSintersearchContent: A threshold for inter-frequency cell reselection in idle mode. When the quality (CPICH Ec/No measured by UE) of the serving cell is lower than this threshold plus the [Qqualmin] of the cell, the inter-frequency cell reselection

d ill b t t d Thi t i t fi d h it l i 127


Cell Reselection CriteriaCriterion R is used for inter-RAT cell reselection

The cell-ranking criterion R is defined by:

nsoffsetnmeasn QQR,, −=

hystssmeass QQR += ,

In Rs, s means serving cell. In Rn, n means neighbor cell.The offset Qoffset1s,n is used for Qoffsets,n to calculate Rn. The hysteresis Qhyst1s is used for Qhysts to calculate Rs. Qoffset1s is for per neighbor direction.Criterion R is also used for intra-frequency, inter-frequency cell reselection

The UE shall rank the cells according to the R criterion, derive Qmeas,n and Qmeas,sand calculate the R values, as described in the following cases:

If a TDD or GSM cell is ranked as the best cell, the UE shall reselect that TDD or GSM cell.


Hysteresis and Time Interval

Treselection

In all the previous cases, the UE can reselect a new cell only when the following conditions are met:

The new cell is better ranked than the serving cell during a time interval Treselections.More than one second has elapsed since the UE camped on the current serving cell.


Parameters of R CriteriaQualMeas

Parameter name: Cell Sel-reselection quality measure

Recommended value: CPICH_ECNO

For 3G/2G cell reselection, the criterions always is

CPICH_RSCP, no matter this parameter is configured as what.

Treselections

Parameter name: Reselection delay time

Recommended value: 1, namely 1s

QualMeasContent: Measurement quantity of cell selection and reselection. It can be set to CPICH Ec/N0 or CPICH RSCP.Value range: CPICH_ECNO(CPICH Ec/N0), CPICH_RSCP(CPICH RSCP)Physical value range: CPICH_ECNO, CPICH_RSCPPhysical unit: NoneSet this parameter through ADD UCELLSELRESEL, query it through LST UCELLSELRESEL, and modify it through MOD UCELLSELRESEL.

TreselectionsContent: If the signal quality of a neighboring cell is better than that of the serving cell during the specified time of this parameter, the UE reselects the neighboring cell. It is used to avoid ping-pong reselection between different cells. Value range: 0~31Physical value range: 0~31; step: 1Physical unit: sSet this parameter through ADD UCELLSELRESEL, query it through LST UCELLSELRESEL, and modify it through MOD UCELLSELRESEL.


Parameters of R Criteria (Cont.)IdleQhyst1s

Parameter name: Hysteresis 1 for idle mode

Recommended value: 2, namely 4dB

ConnQhyst1s

Parameter name: Hysteresis 1 for connected mode (FACH

mode, but only when SIB 12 is implemented, this parameter

takes effect. Otherwise, during connected mode, IdleQhyst1s

takes effect)


IdleQhyst1sContent: The hysteresis value of the serving FDD cells in idle mode in case the quality measurement for cell selection and reselection is set to CPICH RSCP. It is related to the slow fading feature of the area where the cell is located. The greater the slow fading variance is, the greater this parameter.Value range: 0~20Physical value range: 0~40; step: 2Physical unit: dBSet this parameter through ADD UCELLSELRESEL, query it through LST UCELLSELRESEL, and modify it through MOD UCELLSELRESEL.

ConnQhyst1sContent: The hysteresis value of the serving FDD cells in connected mode in case the quality measurement for cell selection and reselection is set to CPICH RSCP. It is related to the slow fading feature of the area where the cell is located. The greater the slow fading variance is, the greater this parameter . Value range: 0~20Physical value range: 0~40; step: 2Physical unit: dBSet this parameter through ADD UCELLSELRESEL, query it through LST UCELLSELRESEL, and modify it through MOD UCELLSELRESEL.

Actually, there are IdleQhyst2s and ConnQhyst2s also. But these two parameters are for Ec/No, but 3G-2G cell reselection, just RSCP is considered. So for 3g-2G cell reselection, this two parameters are no meaning.


Parameters of R Criteria (Cont.)Qoffset1sn

Parameter name: Qoffset1sn


Qoffset1snContent: Offset of cell RSCP measurement value in WCDMA/GSM cell selection or reselection when the UE is in idle mode. Value range: -50~+50Physical value range: -50~+50; step: 1Physical unit: dBSet this parameter through ADD GSMNCELL ， LST GSMNCELL ， MOD GSMNCELL.


SummaryIn this course, we have learned:

Two kinds of 2G/3G PLMN division

2G-3G cell reselection relevant parameters

2G-3G cell reselection processing

3G-2G cell reselection algorithm and parameters

Thank youwww.huawei.com

fmln pdf

Documents

3g coverage area

3g neighbor cell

ue support 2g

2g cell reselection

cell reselection

plmn id

support r99

ue behaviors