Ericsson Mobility Design Version History Version Issue Date Updated By 2G Workbook 3G Workbook 4G Workbook 1 19/6/2020 Andy Malloy / Rod Hewitt / Clive Larkin G18Q2_Issue1.5 W19.Q2 v1.2 L19.Q4 v4.0 2 Index 1 4G Idle Mode Mobility 8 2G Idle Mode Mobility 2 4G Connected Mode Mobility 9 2G Dedicated Mode Mobility 3 4G Carrier Aggregation 4 3G to 4G Connected Mode Mobility 5 3G Connected Mode Mobility 6 3G Idle Mode Mobility 7 3G Inter-RNC Mobility 3 High Level Mobility Overview All RATs • All Telefonica users are allowed to use 4G, 3G and 2G • 4G is the preferred service layer • 3G is the Voice layer where 4G VoLTE is not available • 3G is a coverage fallback layer for voice and data • 2G is a coverage fallback layer as a last resort • All capable UEs should return to 4G as soon as possible • Femto are a reselection only object, no dedicated procedures are supported When using 4G • Voice is enabled using VoLTE in voice enabled TACs • Up to 5 carriers are deployed in total, 3 Carrier aggregation on FDD only • UEs are directed to the higher bands in idle mode • CS fallback allowed to 3G or 2G (3G preferred) • SRVCC allowed to 3G only (TEF only, VF allow 2G as well) • Inter-frequency load balancing is enabled for data • Intra frequency handover is allowed on all carriers • Inter-frequency handover is allowed between carriers on the same sector • Coverage triggered PS Handover to 3G only When in 3G • U900 is the main 3G coverage layer by RF range rather than parameterised steering • 3G to 4G handover is not supported • Fast Return to 4G is supported for CSFB only • Intra frequency handover is allowed for all carriers • Inter frequency handover is allowed for CS only (U2100 / F4) • Inter RAT handover is allowed for CS only for VF only • No Inter RAT handover is allowed for TEF • No Inter RAT / Inter Frequency mobility is allowed out of F3 (TEF) When in 2G • 2G to 3G dedicated mode handover is deployed • Priority based reselection to 4G • Fast return on channel release enabled to 3G and 4G • Intra-2G dedicated mode handover is enabled • Urgency based handover is enabled • Cell load sharing and assignment to worse cell is allowed 4 4G Mobility – Carrier Information LTE Frequency Allocations CELL TYPE TEF L800 CID = 110, 120, 130, 140, 150, 160 TEF L1800 CID = 114, 124, 134, 144, 154, 164 TEF L1800 (Small Cells) CID = 114 TEF L2100 (10 MHz) CID = 115, 125, 135, 145, 155, 165 TEF L2100 (5 MHz) CID = 115, 125, 135, 145, 155, 165 TEF L2300_Carrier 1 CID = 116, 126, 136 TEF L2300_Carrier 2 CID = 117, 127, 137 TEF L900 (5 MHz) VF L800 CID = 10, 20, 30, 40, 50, 60 VF L1800 CID = 14, 24, 34, 44, 54, 64 VF L2100 (10 MHz) CID = 15, 25, 35, 45, 55, 65 VF L2100 (15 MHz) CID = 15, 25, 35, 45, 55, 65 VF L2600 CID = 18, 28, 38, 48, 58, 68 LTE BAND LTE FDD BAND 20 LTE FDD BAND 3 LTE FDD BAND 3 LTE FDD BAND 1 LTE FDD BAND 1 LTE TDD BAND 40 LTE TDD BAND 40 LTE FDD BAND 8 LTE FDD BAND 20 LTE FDD BAND 3 LTE FDD BAND 1 LTE FDD BAND 1 LTE FDD BAND 7 EARFCN DL EARFCN Bandwidth UL (MHz) Bandwidth (PRB) DL FREQ UL FREQ (MHz) (MHz) IDENTIFIER 6400 24400 10 MHz 50 PRB 816 857 L1 1226 19226 5 MHz 25 PRB 1807.6 1712.6 L2 1228 19228 5 MHz 25 PRB 1807.8 1712.8 199 18199 10 MHz 50 PRB 2129.9 1939.9 L7 224 18224 5 MHz 25 PRB 2132.4 1942.4 L3 39250 39250 20 MHz 100 PRB 2360 2360 L4 39448 3700 39448 21700 20 MHz 5MHz 100 PRB 25 PRB 2379.8 950.0 2379.8 905.0 LD LE 6300 24300 10 MHz 50 PRB 806 847 L5 1288 5 MHz 25 PRB 10 MHz 50 PRB 1813.8 2144.7/ 2139.9 1718.8 1954.7/ 1949.9 L6 347/299 19288 18347/ 18299 323 18323 15 MHz 75 PRB 2142.3 1952.3 LA 2850 20850 20 MHz 100 PRB 2630 2510 L8 6 L9 4G Mobility – Neighbour Allocation Rules 4G Neighbour Allocation Rules The parameter cellRelHoAttRateThreshold controls when ANR creates or removes a EUtranCellRelation MO. The EUtranCellRelation MO is created when the threshold for cellRelHoAttRateThreshold is reached. If the daily handover rate goes below the threshold during the timespecified in parameter removeNrelTime, the EUtranCellRelation MO is removed but kept as a candidate EUtranCellRelation . To stop the conversion of EUtranCellRelation, from candidate EUtranCellRelation to EUtranCellRelation MO and vice versa, set the parameter cellRelHoAttRateThreshold to zero. If anycandidate EUtranCellRelation exists at that time, they will beconverted to EUtranCellRelation MO at the next handover attempt or if the EUtranCellRelation MO is created manually. No moreconversions will be done when no candidate EUtranCellRelation exist, that is when all parameter candNeighborRel on the EUtranFreqRelation MOs are empty. If the conversion needs tobe stopped immediately contact Ericsson Personnel for support to delete all candidate EUtranCellRelation. ANR Detection of Problematic Cells functionality, when activated, can create an addition tothe rules for moving cell relations between the candidate cell relation list and EUtranCellRelation MOs. This depends on hoSuccLevel and problematicCellPolicy . See section ANR Detection of Problematic Cells for the functionality description. If the maximum number of possible intra-LTE cell relations, EUtranCellRelation , or external eNodeBs, ExternalENodeBFunction , stored in the MOM, is reached, ANR will stop adding neighbors. That is, alladditional neighbors found are, if cellRelHoAttRateThreshold is setto higher than zero, kept in the candidate list until the MOM stored neighbor list size isreduced. If cellRelHoAttRateThreshold is setto zero, they will instead be discarded. Furthermore, if the maximum candidate EUtranCellRelation for one EUtranFreqRelation isreached and there is no more room for new neighbor relations, an older candidateEUtranCellRelation, still not being converted into an MO EUtranCellRelation, will be swapped out from thelist to make room for the new neighbor relation instead. 8 4G ANR Rules ANR can be used together with manual optimization of neighbour lists and also removes neighbouring cell relations that have not been used within a configurable time period. L2300 L2300 L2100 L2100 L800 L800 L1800 L1800 The diagram above gives some example ANR paths. - Intra Frequency ANR is permitted between all cells on the same EARFCN - Inter Frequency ANR is NOT permitted when moving up the carrier layers, these relationships are manually added between layers on the same sector - Inter Frequency ANR is permitted between all cells when moving down the carrier layers - ANR is also enabled to WCDMA for both TEF and VF, but GSM for VF only Activation parameters and addition thresholds 9 RIM (Redirect with System Information) The benefit of Redirect with System Information feature is that it improves outage time when the User Equipment (UE) is redirected from LTE to GSM, WCDMA or TD-SCDMA (TDD only). This is, for example, important when performing a Circuit Switched (CS) fallback from LTE to a GSM, WCDMA or TD-SCDMA network since the UE is able to connect to the circuit switched domain faster. External cells in the eNodeB hold information about cells in GERAN, UTRAN, E-UTRAN or TD-SCDMA networks. Relations are established between cells in the eNodeB and in GERAN, UTRAN, E-UTRAN or TD-SCDMA networks. A RAN Information Management association is created between the serving BSS and the target BSS for redirecting the UE with system information. The redirection with system information works between the cell on the serving BSS (eNodeB) and the cell on the target BSS (BSC or RNC node). Parameters controlling RIM 10 4G Mobility – Neighbour Topology 4G Neighbour Topology – InterF / RAT Inter LTE EutraNetwork EutranFrequency EutranFreqRelation EutranCellRelation EUtranCellTDD:: L2300 EUtranCellFDD :: L2100 EUtranCellFDD :: L800 EUtranCellFDD :: L1800 Inter RAT – 2G GeraNetwork GeranFrequency GeranFreqGroupRelation GeranCellRelation ExternalUtranCell :: U900 ExternalGeranCell :: U900 12 Inter RAT – 3G UtraNetwork UtranFrequency ExternalUtranCellFDD UtranCellRelation 4G Idle Mode Mobility 4G Idle Mode Mobility – 4G to 3G/2G RSRP Based Reselection cellReselectionPriority dB Source Layer L800 L800 3 L1800 2 L2100 3 L2300T1/2 3 L1800 2 2 2 2 Target Layer L1800 GSM WCDMA _ALT L2100 L2300 (Any) (Any) 6 4 5 0 1 6 2 2 0 1 6 4 5 0 1 6 4 5 0 1 EUtranCellFDD::qRxLevMin 4 dB Within 4G UtranFreqRelation::threshServingLow 0 dB To 3G cellReselectionPriority ThreshXLow ThreshXHigh dB dB dB EUtranFreqRelation UtranFreqRelation GeranFreqGroupRelation L2300 L2100 -124 dBm EUtranCellFDD::threshServingLow - Idle mode mobility prioritises the highest layer where available in the Macro RAN. - L1800 has ‘sticky carrier’ settings deployed – this prevents idle mode reselection into the layer but effectively keeps you there once you get there (through others mechanisms). - EARFCN 1228 is an L1800 offset frequency used for a femto cell layer and this has the highest priority. - qOffsetEUTRA is an additional idle mode offset introduced and managed by the AMO feature Within 4G To 3G To 2G See tables below L800 - L900 has recently been added and the design is being updated. - L2300T2 has the same design as L2300T1 L1800 Target Layer ThreshXLow dB ThreshXHigh dB Source Layer L800 L1800 _ALT L1800 L2100 GSM (Any) L2300 WCDMA (Any) UMTS Target Layer Source Layer L800 L1800 _ALT L1800 L2100 GSM (Any) L2300 WCDMA (Any) L1800 0 0 0 0 0 4 4 L1800 4 4 10 4 4 4 4 L2100 10 10 0 0 0 4 4 L2100 4 4 10 4 10 4 4 L2300T1/2 10 10 0 10 0 4 4 L2300T1/2 4 4 10 4 4 4 4 L800 0 10 0 0 0 4 4 L800 4 4 10 10 10 4 4 GSM 14 4G Idle Mode Mobility - Parameters Layer Priority Parameter: Managed Object: Within 4G = To 3G = To 2G = Key Reselection Parameters cellReselectionPriority EutranFreqRelation UtranFreqRelationand GeranFreqRelation Target Layer Source Layer L800 L1800 L2100 L2300T1/2 L800 3 2 3 3 L1800_AL T 6 6 6 6 L2300T1 5 2 5 5 L1800 2 2 2 2 L2100 2 4 4 WCDMA (Any) 1 1 1 1 GSM (Any) 0 0 0 0 15 3GPP Parameter Ericsson Parameter Value Qrxlevmin qRxLevMin -124 dBm Qqualmin qQualMin -34 (Not used) SintrasearchP sIntraSearch 62 (-62 dBm) SnonIntraSearchP sNonIntraSearch 8 (-116 dBm) Qhyst qHyst 4 dB TreselectionRAT tReselectionEutra 2s TreselectionUTRA tReselectionUtra 2s TreselectionGera tReselectionGeran 2s 4G Connected Mode Mobility 4G Intra-Frequency Handover Event A3 Target > Source by: • Offset • Hysteresis • Time to trigger Serving 4G Cell MO ReportConfigEUtraBestCell ReportConfigEUtraBestCell ReportConfigEUtraBestCell ReportConfigEUtraBestCell Target 4G Cell Note: sMeasure = 0 (Disabled) 17 Parameter Name triggerQuantityA3 a3offset hysteresisA3 timeToTriggerA3 TEF O2 UK value RSRP 30 (3dB) 10 (1dB) 480 ms 4G Inter-Frequency Handover Based on IFLB • In Idle Mode, Ue are directed to reselection onto the highest available EUTRAN carrier • These ‘capacity layers’ then risk becoming congested and hence it is allowed to Load Balance ‘down’ to other co-sector carriers to distribute load evenly. L2300 L2100 • L800 L1800 Note: sMeasure = 0 (Disabled) 18 Valid Load Balancing routes are shown to the left – there is no Load Balancing INTO L2300 4G Inter-Frequency / Inter RAT Handover The Mobility Control at Poor Coverage feature is used. This introduces a concept of an Inner and Outer search zone as RSRP degrades. These level based zone dictate what mobility options the Ue has when residing in each of these zones. It is possible to configure the eNodeB such that the search zone is divided into an inner and an outer search zone. This is for RSRP by setting the ReportConfigSearch.a2OuterSearchThrRsrpOffsetattributes to a value lower than 0. The UE only uses an inner/outer search zone if there are low priority frequency relations, which are searched for in the outer, but not the inner, search zone. That is, only if there are frequency relations where the priority attribute has a value lower than (but not equal to) the value of the UeMeasControl.lowPrioMeasThresh MO attribute. In other cases, a standard search zone is used. 19 4G Inter-Frequency / Inter RAT Handover Data A1 event triggered with improving RSRP a1a2SearchThresholdRsrp = -118dBm / -116dBm (non L800 cell) hysteresisA1a2SearchRsrp = 20 (2dB) A2OuterSearchThrRsrpOffset = -2dB A1 A2 Bad Coverage a2CriticalThresholdRsrp = -130dBm L800 -116dBm -120dBm Look for other 4G carriers and 3G Release with redirect Others -114dBm A2 Search Inner -118dBm A2 Search Outer -120dBm Capacity layers introduce the concept of an Inner and Outer search within which mobility is only allowed Intra LTE. This zone does not exist in the L800 coverage layer. Look for other 4G carriers 20 4G Inter-Frequency / Inter RAT Handover Voice a1a2SearchThresholdRsrp = -118dBm / -116dBm (non L800 cell) hysteresisA1a2SearchRsrp = 20 (2dB) A2OuterSearchThrRsrpOffset = -2dB A1 A2 Bad Coverage a2CriticalThresholdRsrp = -130dBm L800 -112dBm -116dBm Others -110dBm A2 Search Inner -114dBm -116dBm The parameters in the table to the left are used to modify the existing threshold parameters for bearers with QCI 1 setup in conjunction with the Service Based Mobility feature. A2 Search Outer Look for other 4G carriers 21 4G Inter-Frequency / Inter RAT Handover Target Cell ‘Good Enough’ Voice subject to additional offsets for 3G RSRP, 3G Ec/No and 2G RXLev 22 4G CS Fallback 4G CS Fallback • CSFB may use RIM, this is covered on separate slide • Equal priority between F3 and F4 • F4 only defined as target when it exists on the co-site L2300 L2100 L800 Round Robin Target Cell U900 F3 U900 F4 24 L1800 4G Carrier Aggregation Allowed CA Combinations Assuming Ue Support • Any combination of 2 or more carriers • FDD - TDD CA deployed, TDD cannot be a PCell • Only allowed intra-sector • Note: currently no CA with L2300 TDD layer where 5G deployed • Enabled through neighbouring and eUtranCellRelation::sCellCandidate 26 3G Mobility – Carrier Information UMTS Frequency Allocations DLFrequenc DL UARFCN UL UARFCN y UL Frequency Identifier Operator Band O2 I 10637 9687 2127.4 MHz 1937.4 MHz F1 & femto O2 I 10661 9711 2132.2 MHz 1942.2 MHz F2 O2 VIII 2963 2738 932.6 MHz 887.6MHz F3 O2 VIII 3050 2825 950.0 MHz 905.0 MHz F4 VF I 10687 9737 2137.4 MHz 1947.4 MHz F5 & femto VF I 10712 9762 2142.4 MHz 1952.4 MHz F6 VF VIII 2987 2762 937.4MHz 892.4MHz F8 VF VIII 2938 2713 927.6 MHz 882.6 MHz F9 28 3G Mobility – Allocation Rules 3G TFinTF Neighbour Relation Limits Limits imposed due to restriction in SIB11 length • F1 cells: Up to 28 intra-frequency, 32 inter-frequency, 32 IRAT, but total has to be equal/less than 62 UMTS F1 UMTS F2 UMTS F3 UMTS F4 Intra Freq. Up to 28 Up to 31 Up to 31 Up to 31 Inter Freq. Up to 32 Up to 29 Up to 29 Up to 32 GSM Up to 32 Up to 32 Up to 32 Up to 32 Total <= 62 Total <= 62 Total <= 62 Total <= 62 30 • F2 cells: Up to 31 intra-frequency, 29 inter-frequency, 32 IRAT, but total has to be equal/less than 62 • F3 cells: Up to 31 intra-frequency, 29 inter-frequency, 32 IRAT, but total has to be equal/less than 62 • F4 cells: Up to 31 intra-frequency, 32 inter-frequency, 32 IRAT, but total has to be equal/less than 62 3G Mobility – Neighbour Topology 3G - 3G Neighbouring Rules Co-Site Co-Sector U900 F4 / F8 Inter-Site U900 F4 / F8 U900 F4 / F8 U900 F3 / F9 U900 F3 / F9 U900 F3 / F9 U2100 F2 / F6 U2100 F2 / F6 U2100 F2 / F6 U2100 F1 / F5 U2100 F1 / F5 UE camped on F1 F2 F3 F4 F5 F6 F9 F8 UE measuring F1, F2 & F3 F1, F2 & F3 F1, F3 & F4 F1, F3 & F4 F5, F6 & F9 F5, F6 & F9 F5, F9 & F8 F5, F9 & F8 U2100 F1 / F5 UtranRelation::mobilityRelationType CELL_RESELECTION_ONLY(2) HO_AND_CELL_RESEL(0)– CS and PS HO_AND_CELL_RESEL(0)– CS Only, no PS U2100 FEMTO F1 / F5 Reselection biased towards Femto using UtranRelation::qOffset2sn = -40dB. Handover biased against Femto using UtranRelation::selectionPriority = 99 (lowest) 32 UtranCell::hoType = 0 (IFHO_PREFERRED) For U21 Cells UtranCell::hoType = 2 (NONE) For U9 F3 Cells UtranCell::hoType = 4 (IFHO ONLY) For U9 F4 Cells UtranCell::hoType = 3 (IF GSM_PREFERRED) For U9 F8 Cells UtranCell::hoType = 1 (GSM_PREFERRED) For U9 F9 Cells 3G Ericsson Coverage Relation (Load Sharing) Rules Co-Sector • Coverage relations are defined for load sharing purposes U900 F4 • Co-sector coverage relations are mandatory (bidirectional) U900 F3 • When the F3 or F4 sector is not co-aligned with the F1 or F2 sector, the sector with the closest azimuth will be defined U2100 F2 • Note: Coverage relations are independent from UTRAN relations Only applicable for Ericsson RAN U2100 F1 33 3G Inter-RAT (GSM) Neighbouring Rules (TEF) Co-Site • IRAT co-sector neighbour relations are mandatory • IRAT co-sited neighbour relations are mandatory • IRAT inter-site tier 1 relations are mandatory for U900 • Co-Sector Inter-Site U900 F4 U900 F3 IRAT inter-site tier 1 relations are optional for U2100 U2100 F2 U2100 F1 GSM 900 GSM 900 GSM 900 GsmRelation::mobilityRelationType HO_AND_CELL_RESEL(0). HO behaviour is controlled by UtranCell:hoType, all ISHO disabled in Tef. PSHO is disabled by UeRc::gsmHoSupport 34 Note that the mobilityRelationType on GsmRelation has been kept as is even though ISHO to GSM has been disabled with UtranCell::hoType. It can be re-enabled at cell level in case in site specific scenarios 3G Inter-RAT (GSM) Neighbouring Rules (VF) Co-Site • IRAT co-sector neighbour relations are mandatory • IRAT co-sited neighbour relations are mandatory • IRAT inter-site tier 1 relations are mandatory for U900 • Co-Sector Inter-Site U900 F4 U900 F3 IRAT inter-site tier 1 relations are optional for U2100 U2100 F2 U2100 F1 GSM 900 GSM 900 GsmRelation::mobilityRelationType HO_AND_CELL_RESEL(0)– CS Only, no PS. IFHO is attempted first. HO behaviour is controlled by UtranCell:hoType. PSHO is disabled 35 by UeRc::gsmHoSupport GSM 900 3G Inter-RAT (LTE) Neighbouring Rules L2300 L2100 L1800 L800 Properties defined in EutranFreqRelation MO U2100 f2 U2100 f1 U900 f4 U900 f3 36 3G Idle Mode Mobility 3G Idle Mode Overview • Within 3G • Towards 4G • General qQualMin = -18dB sIntrasearch = 25 (16dB) sInterSearch = 23 (12dB) tReselection = 3s qHyst2 = 2dB • Features employed to move from 3G to 4G by default as soon as possible These support priority based reselection in idle mode and redirection in dedicated mode EutranFreqRelation::cellReselectionPriority = Highest EutranFreqRelation::qRxLevMin = -124 dBm (target RSRP) EutranFreqRelation::threshHigh = 8 (-116 dBm) UtranCell::tReselection = 3s • Within Macro Always searching, intra-freq first. qOffset2sn = 0 for all intra-RNC relations • Towards 2G • Towards Femto qOffset2sn = -40dB • sRATSearch = 2dB Search for reselection to 2G as a last resort Note: Idle in Macro across Iur is biased away from DRNC cell using UtranRelation::qOffset2sn = 3dB 38 3G Idle Mode Mobility – Reselection from 3G to Other RAT L2300 L2100 L800 L1800 EutranFreqRelation MO Reselection with Dedicated Priorities (Idle/PCH) cellReselectionPriority Release with Redirect (DCH) redirectionOrder L1800 5 2 L800 6 (highest) 1 (highest) EutranFreqRelation::cellReselectionPriority = Highest EutranFreqRelation::qRxLevMin = -124 dBm (target RSRP) EutranFreqRelation::threshHigh = 8 (-116 dBm) UtranCell::tReselection = 3s UMTS UtranCell::sRATSearch = 2 (-16 dBm) 2G to 3G and 2G to 4G reselection covered on separate slides GSM UtranCell::qQualMin = -18 dBm 39 3G Connected Mode Mobility 3G IntraFrequency Handover Parameterisation Event 1a/1b • Intra-Frequency Soft and Softer Handover • Soft and softer handover are controlled through the events 1a, 1b, 1c, and 1d in the following ways: • 1a: A new candidate for the active set enters reporting range • 1b: A cell in the active set leaves the reporting range • 1c: A cell not in active set becomes stronger than a cell in the active set • 1d: Any cell becomes better than the best cell in the active set event 1a event 1b event 1c event 1d Event add remove replace replace best UeMeasControl reportingRange Hysteresis timeToTrigger 4dB 0dB 320ms 6dB 0dB 2560ms 1dB 320ms 7.5dB 2560ms Event 1c 41 3G Inter Freq /IRAT Compressed Mode Settings Trigger Used Frequency Report Controlling Parameter Name DL Transmitted usedFreqThresh serviceOffset2d Code Power 2dRscp Rscp CPICH Ec/No CPICH RSCP UL for UE TX power Parameter Value DL Transmitted Code Power CPICH Ec/No CPICH RSCP usedFreqThresh 2dEcno usedFreqThresh 2dRscp usedFreqThresh 2dRscp -115 -21 -115 UL for UE TX -115 power Parameter Managed Object DL Transmitted Code Power UtranCell UtranCell CPICH Ec/No serviceOffset2dE cno serviceOffset2d Rscp serviceOffset2d Rscp 0 dB for Voice, 2 dB for Data 0 dB for Voice, 2 dB for Data 0 dB for Voice, 2 dB for Data usedFreqRelThre dlCodePwrRelTh nonUsedFreqThr serviceOffset2d sh4_2bRscp reshRscp esh4_2bRscp Rscp usedFreqRelThre sh4_2bEcno usedFreqRelThre sh4_2bRscp usedFreqRelThre sh4_2bRscp nonUsedFreqThr esh4_2bEcno nonUsedFreqThr esh4_2bRscp utranRelThreshR nonUsedFreqThr scp esh4_2bRscp serviceOffset2dE cno serviceOffset2d Rscp serviceOffset2d Rscp 0 5 -104 0 - -13 0 - -104 0 dB for Voice, 2 dB for Data 0 dB for Voice, 2 dB for Data 0 dB for Voice, 2 dB for Data -104 0 dB for Voice, 2 dB for Data 0 dB for Voice, 2 dB for Data 0 5 UeRc UeRc UeMeasControl UeMeasControl RbsMeasControl UeMeasControl UeMeasControl UeRc UeRc UeMeasControl - UeMeasControl UeRc UeMeasControl UeMeasControl UeMeasControl UeMeasControl UtranCell UeRc CPICH RSCP UL for UE TX Add evaluation example here DL Transmitted Code Power triggers Data. Evaluated againstUeRc z for target powerat x for Voice, y forUtranCell CPICH Ec/No CPICH RSCP UL for UE TX power Non Used Frequency Report 42 usedFreqThresh 2dEcno usedFreqThresh 2dRscp usedFreqThresh 2dRscp -21 -115 -115 3G TFinTF Inter-RNC Mobility • SRNS Relocation is not supported in Ericsson RAN • All Inter-RNC mobility is provided by Anchoring over the Iur • Separate parameters for mobility over Iur can be defined using the same parameter names but different managed objects (Mos): • IurLink • ExternalUTRANCell 43 Fast Return 3G to 4G Return from 3G to 4G (Idle / Data) Return from 3G to 4G as soon as possible both in Idle/PCH and Dedicated Mode States L2300 Mode: Feature: Idle / PCH DCH FAJ 121 1474 LTE Cell Reselection FAJ 121 2174 Release with Redirect to LTE EutranFreqRelation:: cellReselectionPriority EutranFreqRelatio n:: redirectionOrder L1800 5 2 L800 6 (highest) 1 (highest) Parameter: L2100 UtranCell:: releaseRedirect L1800 3G Cell Collocated with 4G = EUTRA Otherwise = OFF L800 Currently RwR triggered for CSFB case only Any UMTS 45 Return from 3G to 4G (Voice) Non-Colocated Sectors Colocated Sectors For all cases: In Idle – Priority Based Reselection In Dedicated – Release With Redirect (Blind Redirection) L2300 L2100 L1800 L2100 L800 L800 L800 P1 P1 P1 Any UMTS Any UMTS Any UMTS P2 L800 P1 Any UMTS 46 3G Load Balancing Configuration 3G Load Balancing Feature Admission block redirection (FAJ 121 1593) HSDPA IFLS (FAJ 121 1467) Non-HSPA IFLS (FAJ 121 1468) Acts on… RRC or Speech blocking • RRC Block to GSM • RRC Block to Inter-Frequency • RAB Speech Block Directed Retry Balancing HSDPA, EUL Balancing DCH (including Speech) 48 Feature Configuration RRC to GSM = ON for U900 only RRC to IF = OFF Speech (Directed Retry) = ON Enabled Enabled 2G Mobility – Carrier Information 2G Carrier Information 50 2G Mobility – Neighbour Allocation Rules 2G Neighbour Allocation Rules • Maximum of 12 2G – 3G Neighbours allowed per 2G Cell (minimise the possibility of handing to distant 3G neighbours) • Co-Sector and Co-Site are mandatory to F3 and F1 (if F1 exists) • 3 Femto Nbrs Required for TEF; 6 Femto Neighbours Required for VF. 52 2G Mobility – Neighbour Topology 2G Neighbour Capabilities 1 If WCDMA cells shall be defined for cell reselection, no more than 31 GSM cells may be defined for cell reselection measurements in idle mode. 2 If WCDMA cells shall be defined for active mode measurements, no more than 31 GSM cells may be defined for active mode measurements. 3 Mobility in idle and packet transfer mode to and from LTE FDD and LTE TDD supported. 4 Up to 64 UTRAN cells related to up to 32 UTRAN frequencies may be defined for cell reselection measurements in idle and packet transfer mode. 3GPP TS 45.008 has a requirement on the mobile stations in idle mode to monitor 3 frequencies with 32 cells per frequency. If this limit is exceeded, the MS behavior is unspecified. 5 Up to 64 UTRAN cells related to up to 32 UTRAN frequencies may be defined for active mode measurements.3GPP TS 45.008 has a requirement on the mobile stations in active mode to monitor 3 frequencies with 32 cells per frequency. If this limit is exceeded, the MS behavior is unspecified. 6 Up to 8 LTE frequencies may be defined for cell reselection. For each frequency defined, one less GSM cell may be defined for cell reselection. 3GPP TS 45.008 has a requirement on the mobile stations in idle mode to monitor 3 FDD+ 3 TDD frequencies. If this limit is exceeded, the MS behavior is unspecified. 7 Up to 8 LTE frequencies may be defined for active mode measurements. For each frequency defined, one less GSM cell may be defined for active mode measurements.3GPP TS 45.008 has a requirement on the mobile stations in active mode to monitor 3 FDD+ 3 TDD frequencies. If this limit is exceeded, the MS behavior is unspecified. 54 2G Idle Mode Mobility 2G – 2G Idle Mode – Cell Selection The MS continuously calculates the C1 criterion. The derived Received Level Average (RLA_C), needed for calculating the C1 criterion, is based on signal strength measurement samples. The measured values are stored in a running average filter using samples collected over a period of 5 seconds or 5 consecutive paging blocks, whichever is longest. To receive a valid measurement at least 5 received signal strength measurement samples are required per BCCH carrier. How frequent an MS is required to update RLA_C is described in 3GPP Technical Specification 45.008. The measurements and the verification of BSIC performed on the frequencies indicated in the BA list used. The 3GPP Technical Specifications 45.008 refers to this criterion as “path loss criterion parameter” even though the C1 criterion is based only on signal strength and not on path loss. C1 = RLA_C - ACCMIN - max(CCHPWR - P, 0) where: ACCMIN is the cell parameter that indicates the minimum received signal level at the MS required for accessing the system. CCHPWR is the cell parameter that indicates the maximum transmitting power that an MS is allowed to use when accessing the system. P is the maximum power output of the MS according to its class. The cell selection criterion is satisfied if C1 > 0. The C1 criterion will, as a consequence, limit access for MSs that receive high enough signal strength for successful downlink communication, but are weak in the uplink 56 2G to Other RAT Idle Mode Mobility • A number of mechanisms exist on 2G for moving traffic to other technologies. • Idle Mode Reselection – older UE which do not support Combined Reselection. • Combined Idle Mode Reselection – Enhanced behaviour for Ue which do not support Priority Based Reselection • Priority Based Reselection – Prioritises 4G over 3G. 57 2G to Other RAT Mobility - UMFI • In circuit switched active mode (speech and data), a Multi-RAT MS is measuring neighboring UTRAN and E-UTRAN cells and reporting to the BSS through measurement reports. To be able to perform inter system measurements a list of UTRAN neighbors, configured with parameter UMFI, is sent to the Multi-RAT MS in the message MEASUREMENT INFORMATION on the SACCH. • These lists can be the same as the list broadcast on BCCH to Multi-RAT MSs in idle mode, but it is also possible to set them separately in order to have different UMTS neighbors in idle and active mode. After changing from idle to active mode, the last list received over BCCH is used (that is, Idle 3G-BA), until a new one is received over SACCH (that is, active 3G-BA). • The Multi-RAT mobile is informed on how many UMTS cells (0-3) that shall be reported in the measurement report. This is set by parameter FDDMRR. BSS informs the mobile which measurement report to use, Measurement Report or Enhanced Measurement Report. 58 2G to other RAT mobility • COEXUMTS is a BSC exchange property which controls the mechanisms in place to facilitate mobility from 2G to other RAT • Current design value is 4 which allows, GSM-UMTS Cell Reselection and Handover allows end-users with Multi-RAT (Radio Access Technology) GSM/WCDMA Mobile Stations (MSs) to roam between UTRAN (UMTS Terrestrial Radio Access Network) and GSM radio access network without loss of service (provided the service is supported in both networks). It gives support for mobility in idle mode (GSM to UTRAN), for handover of circuit switched connections (GSM to UTRAN), and for cell reselection for packed switched service (GPRS/EGPRS to UTRAN). For Cell reselection to UMTS, the operator has the choice to use priority based cell reselection in addition to cell ranking based cell reselection. Combined Cell Reselection Triggering GSM to WCDMA provides the possibility to define a threshold for CPICH RSCP measurements to be used at cell reselection. The threshold for CPICH RSCP measurements assures a sufficient downlink signal strength, which in turn increases the possibility for the mobile to reach the network in the uplink in the target cell. Combined Handover Triggering GSM to WCDMA provides the possibility to define a CPICH RSCP threshold used to control the measurement reporting of UTRAN cells for MSs being in connected mode or for MSs being in NC2 mode. No UTRAN cells will be included in the measurement reports from the MS unless the non reporting radio entity (CPICH RSCP) have a value above the defined CPICH RSCP threshold. This assures that UTRAN handover candidates have a sufficient downlink signal strength, which in turn increases the possibility for the mobile to reach the network in the uplink in the target cell. GSM-LTE Cell Reselection gives support for cell reselection in idle and packet transfer mode from GSM to LTE (FDD and TDD). This feature also gives possibility to define E-UTRAN cells that are not allowed to select during cell reselection and RSRP and RSRQ thresholds used to control the measurement reporting of E-UTRAN cells. 59 2G Idle Mode Reselection – Inter RAT 3G • Ue through QSC, QSCI are instructed to measure other RAT continuously. • FDDQMIN is the minimum quality of a UTRAN cell for cell reselection. This parameter should not be used to control the cell reselection, but provide a sufficient quality of the candidate UTRAN cell. Set to 6 which gives a minimum Ec/No requirement of -14dB. • FDDQOFF defines an offset between signal quality of UTRAN and GSM cells. This is set to 0 (which equates to and infinite value) and is unused hence the criteria is always met. • This criteria has to be met for a minimum of 5 seconds. • RLA (Received Level Average) is the average of the received signal levels measured in dBm for all monitored GSM frequencies in the BA list. 60 2G Combined Idle Mode Reselection • Ue through QSC, QSCI, instructed to measure other RAT continuously. • FDDQMIN is the minimum quality of a UTRAN cell for cell reselection. This parameter should not be used to control the cell reselection, but provide a sufficient quality of the candidate UTRAN cell. Set to 6 which gives a minimum Ec/No requirement of -14dB. • FDDQMINOFF is 0 keeping FDDQMIN as the controlling threshold • FDDRSRPMIN is set to 4 which equates to -106dBm and the final value of RSRP calculates to -109dB after the 3dB reduction as per the formula below. . 61 2G Priority Based Cell Reselection to 3G / 4G • Ue through QSC, QSCI are instructed to measure other RAT continuously. • Each RAT is allocated a Priority (RATPRIO) as per table below. • L800 is highest priority layer • Cell reselection to a higher priority LTE frequency (always the case) occurs when • Cell reselection to a higher priority WCDMA frequency (always the case) occurs when 62 2G Connected Mode Mobility 2G Dedicated Mode Mobility • The handover decisions are based on signal strength and signal quality measurements performed by the mobile station. The MS measures the strength of the radio signal from the base station that serves the connection. In addition, it measures the signal strength of the BCCH carrier frequency from the surrounding and serving cells. These measurements are used in a comparison, in order to find the "best" server. • When Ericsson3 algorithm is used, all cell borders can be individually moved by cell-to-cell related handover border offset parameters in order to adjust them to the topography or to the traffic situation. In addition they have an individual hysteresis, also by cell-to-cell definable parameters. Separate hysteresis values can be used at low received signal strength and at high signal strength. • A number of urgency and support mechanisms exist to supplement the above measurements and are listed below. • • • • • • • • Urgent Handover in Bad Quality Situations - Used Urgent Handover at Excessive Timing Advance - Used Assignment to Other Cell - Used Hierarchical Cell Structures – No Longer Used Overlaid/Underlaid Subcells – Not Used Intra-cell Handover - Used Extended Range – Not Used Cell Load Sharing - Used 64 2G – 2G Connected Mode Assignment to Other Cell A Mobile Station (MS) in idle mode moving around in the network selects a certain cell, to which it will normally connect in case of a call set-up. At allocation of a traffic channel it may sometimes be better to select a different cell for various reasons. The Assignment to Other Cell feature makes it possible to assign the mobile to another cell than the one selected by the mobile. The Assignment to Other Cell feature operates at call set-up, during which a traffic channel is to be assigned. (Assignment to Other Cell = a handover from the Stand alone Dedicated Control CHannel, SDCCH, in originating cell directly to a Traffic CHannel, TCH, in target cell.) The feature makes it possible to select a traffic channel in another cell than the one that is currently serving the connection. The result, in terms of the effect on the entire network, depends on the radio conditions in the target cell. The target cell is either ranked better than the serving cell in the locating evaluations, or worse. Better cell - When the locating evaluations start at an early stage in the call set-up procedure, the locating evaluations may find cells with a higher locating ranking than the serving cell. To prevent unnecessary handovers and also to improve the general interference environment, the assignment can be redirected to these cells. This is also called Assignment to Better Cell. Worse cell - If a mobile cannot connect to the selected cell due to congestion, assignment to a cell with a lower locating ranking than the serving cell can be recommended. The probability for a call to get a usable connection to the network will then increase. This is in CME 20 called Assignment to Worse Cell. It is also, in GSM, known as Directed Retry. ASSOC is a parameter that turns the feature Assignment to Other Cell on or off. ASSOC is set to ON if the feature Automatic Handover Optimization is ON at least in one internal cell. It is not possible to set ASSOC to OFF if the feature Automatic Handover Optimization is ON at least in one internal cell. The parameter is set per BSC. AW determines if an assignment to a worse cell is allowed from that cell. However, to allow assignment to a worse cell, the parameter ASSOC has to be set to ON as well. AW is set to OFF in cells where the feature Automatic Handover Optimization is ON. It is not possible to set AW to ON in cells where the feature Automatic Handover Optimization is ON. The parameter is set per cell. IBHOASS determines whether an assignment to another BSC can be performed. The parameter is set per BSC. AWOFFSET is a signal strength offset parameter. It defines the maximum range of the signalstrength corridor between a congested serving cell and its neighbour, in where the neighbour cells are eligible as candidates for Assignment to Worse Cell. For example: The MS measures SS (serving cell) = -70, AWOFFSET = 15 allows assignment to neighbour with SS = -85 or stronger. The parameter is set per neighbour cell relation. CAND is set per neighbour cell relation and specifies if the neighbour cell shall be treated as a possible candidate at assignment and at handover. The parameter can take the following values: AWN, the cell is a possible candidate at assignment to a better or worse cell, but not at normal handover. NHN, the cell is a possible candidate at assignment to better cell and at normal handover. BOTH, the cell is a possible candidate at assignment to a better or worse cell and at normal handover. 65 2G – 2G Connected Mode The purpose of the Cell Load Sharing feature is to distribute some of a cells traffic load to surrounding cells during peaks in traffic. This is achieved by moving established connections to neighbouring cells that have idle resources. The logic of the Cell Load Sharing feature is an integrated part of the Locating algorithm. The Cell Load Sharing feature distributes the traffic load more evenly in a network and reduces the probability of congestion in a cell. This is achieved by moving established connections to neighbouring cells and thereby reducing the high load peaks in the cell. A higher average load can be allowed while the grade of service (allowed congestion level) remains the same. The trunking efficiency of a BSC is thus greater, resulting in an increase in carried traffic and better resource utilisation. Cell Load Sharing increases the number of handovers in the part of the network where the traffic load is unevenly distributed. 66 2G – 2G Connected Mode (Ericsson 3) The locating algorithm serves the purpose of providing possible cell candidates for handover listed in descending ranking. The channel allocation and handover signalling is not considered part of the locating algorithm. The algorithm consists of eight stages, corresponding to the eight boxes in the main flow chart shown to the right. The stages are processed roughly in a chronological manner. 1 Initiations - A locating individual is created. If there has been a previous locating individual handling the same connection, a penalty list and mobile behavior statistics can be received. 2 Filtering - Measured values (for signal strength, quality and timing advance) are filtered by performing an averaging of a number of consecutive measurements. 3 Urgency Conditions - Two types of urgency conditions are evaluated: bad signal quality and excessive timing advance. The signal quality is evaluated in the uplink as well as in the downlink. 4 Basic Ranking - A basic ranking list of cell candidates is prepared. The Ericsson GSM System provides three algorithms for basic ranking: Automatic Handover Optimization, Ericsson1 and Ericsson3. Automatic Handover Optimization and Ericsson3 ranking only consider signal strength. The Ericsson1 ranking (also called K/L-ranking) takes both signal strength and path loss into account. 5 Auxiliary Radio Network Functions Evaluations - The criteria for Overlaid/Underlaid Subcell Change, Hierarchical Cell Structures, Intra-cell Handover, Assignment to Other Cell, Extended Range and Cell Load Sharing are evaluated. 6 Organizing the List - All cells are organized into one final candidate list according to rules that are defined by the outcome of the urgency conditions, the overlaid/underlaid evaluations, the hierarchical cell structures evaluations, intra-cell handover evaluations and cell load sharing evaluations. Additional locating criteria are applied in order to remove unsuitable candidates. 7 Sending the List - The candidate list is sent for further processing to be used for channel allocation. 8 Allocation Reply - The outcome of the channel allocation determines the action. At success, the connection is transferred to another channel and the locating processing is transferred to a new locating individual. At congestion or signalling failure, the connection remains. 67 2G – 2G Intra Cell Handover Intra Cell Handover (IHO) aims at improving the interference situation for a circuit switched connection with sufficient signal strength. This is the situation for a connection with bad measured quality while the received signal strength at the same time is high, which can be the case for a mobile close to its serving base station. When the IHO quality and signal strength conditions (up- or downlink) are met, as for the marked mobiles below, an improvement attempt is done by changing BPC within the cell. IHO is the parameter for switching IHO on or off. The parameter is set per subcell. For the algorithm to trigger an IHO, the received filtered quality values rxqual are used, measured in the up- and downlink in dtqu units. These estimated bit error rate values are used by the algorithm together with the received filtered signal strength values RXLEV measured in the up- and downlink in rxlev units for the IHO triggering criteria, the quality vs. signal strength function, FQSS ( Table 1). It defines the maximum acceptable received quality value (rxqual) for every signal strength value (RXLEV), and thereby for an IHO to be requested the following equation must be fulfilled for uplink or downlink: rxqual > FQSS(RXLEV) There are offset parameters to further adjust the FQSS. The offsets can, besides signal strength and quality, also be set for uplink as well as downlink, and speech version on a per subcell level, though these are all represented in the equation below by SSOFFSET and QOFFSET for simplicity reasons (see further Section 5.1). The offset parameters also have, due to each ranging from negative to positive values, separate positive and negative representations when adjusting offset value for a cell. For example: the negative and positive representation for signal strength offset in the downlink are SSOFFSETDLN and SSOFFSETDLP (command: RLIHC). If the offset parameters are used, they contribute to the equation as below rxqual - QOFFSET > FQSS(RXLEV + SSOFFSET) The signal strength offset parameter (SSOFFSET) is used displace the curve in the horizontal direction to obtain IHOs at desired signal strength level. An increased SSOFFSET (setting a positive value) in the figure will trigger more IHOs, since they will be allowed for connections at lower signal strength. The quality offset parameter (QOFFSET) is used to displace the curve in the vertical direction to obtain IHOs at desired quality level. A decreased QOFFSET (setting a negative value) in the figure will trigger more IHOs, since they will be allowed for connections with lower rxqual values. 68 2G to 3G Handover • The Multi-RAT mobile is allowed to measure 1 UTRAN cell. • The UTRAN is set through QSC/QSCI to be measured constantly. • To be able to perform inter system measurements a list of UTRAN neighbors, configured with parameter UMFI • All valid UTRAN cells must have CPICH Ec/No equal or higher than the value of FDDREPTHR and CPICH RSCP equal or higher than the value of FDDREPTHR2. • MRSL additionally prevents handover to UTRAN cells with poor Ec/No • MRSL to 49 (0dB) towards external FEMTO cells (3 per BSC) Parameter Description Current Settings COEXUMTS BSC Exchange Property used to enable mobility features. 4 ONADDINFO; GSM-UMTS Cell Reselection and Handover, Combined Cell Reselection Triggering GSM to WCDMA and Combined Handover Triggering GSM to WCDMA are activated ISHOLEV Defines the traffic load threshold of the serving GSM cell that needs to be exceeded in order to evaluate UMTS measurements for handovers or when incoming handovers from WCDMA may be rejected. The load is exceeded when the percentage of idle TCH in the serving cell <= ISHOLEV. Comment 99 Setting will only reject incoming 3G2G HO if Service Indication is used and COEXUMTSLSH = 1 MRSL Defines a minimum threshold for the "quality" measure Ec/No for handovers to UTRAN. This parameter is defined per UTRAN cell. 29 (-10dB -> -9.5 dB) Minimum EcNo requirement for target ensures that UTRAN cell has Ec/No better then -9.5dB and prevents pingpong HO back down to GSM. FDDREPTHR2 Defines a threshold for the non reported “signal strength” measure CPICH RSCP of UTRAN cells. The MS includes a UTRAN cell in the measurement reports only if the non reporting threshold is exceeded. It shall be noted that the reporting entity in the measurement reports is CPICH Ec/No. This parameter is defined per GSM cell. The threshold parameter is used by MSs in connected mode and in NC2 mode. 18 (-98dBm) Only report 3G neighbours better than 98dBm RSCP. FDDMRR defines the number of UTRAN cells that the mobile should include in measurement reports. 1 Include 1 UTRAN cell in 2G Measurement Report QSC Defines if the monitoring of UMTS cells will be performed if the signal level is below (0-6) or above the threshold (8-14), always (7) or never (15). This parameter is defined per GSM cell. 7 ( always) Always monitor for UTRAN cells, other parameters govern whether or not they should be reported. QSCI Defines the control of UTRAN measurement after entering active mode, before reading the first QSC. In that period UTRAN measurements can always be performed (=1) or according to QSI value (=0). This parameter is defined per GSM cell. 1 Start monitoring immediately. FDDREPTHR Defines the reporting threshold for CPICH Ec/No measurement reporting of UTRAN FDD. MSs may report only those UTRAN FDD cells for which the measured value of CPICH Ec/No is equal to or higher than parameter FDDREPTHR. This parameter is defined per GSM cell. This parameter corresponds to 3GPP specification parameter FDD_REPORTING_THRESHOLD. 2 (-15.5dB) Only report 3G neighbours better than 15.5dBm. 69 Fast Return 2G to 3G, 2G to 4G Fast Return, 2G to 3G / 4G • Where applicable, a Ue on 2G can be instructed in the Channel Release message to return directly to either 3G or 4G without entering Idle mode on 2G. 3G 4G • If the GSM cell has been configured with an Active UTRAN Measurement Frequency List and up to G12A also a neighbor cell relation to a UTRAN cell, the BSC will direct a mobile to UTRAN when the following criteria are fulfilled: • If the GSM cell has been configured with an Idle E-UTRAN Measurement Frequency List and an Active E-UTRAN Measurement Frequency List, the BSC will direct a mobile to EUTRAN when the following criteria are fulfilled: • 1 The feature is activated. • 1 The feature is activated. • 2 The MS is a multi-RAT mobile. • 2 The MS is a LTE capable mobile. • 3 The parameter QSC has not been set to “never search for UTRAN”. • 3 The MS supports E-UTRAN measurements and reporting. • 4 MS has reported measurements on a UTRAN cell while in dedicated mode (there is UTRAN coverage). • 4 The parameter EQSC has not been set to “never search for E-UTRAN”. • 5 MS has reported measurements on a E-UTRAN cell while in dedicated mode (there is E-UTRAN coverage). • 6 Reported RSRP is equal or higher than value of minimum allowed RSRP level for EUTRAN FDD or E-UTRAN TDD. In case of reporting with measurement reports, parameters EFDDRSRPLEV and ETDDRSRPLEV respectively are used, and in case of reporting with enhanced measurement reports, parameters EFDDRSRPLEVEMR and ETDDRSRPLEVEMR respectively are used. • 5 Reported CPICH Ec/No level is equal or higher than value of the parameter FDDSQTHR. 71 Fast Return, 2G to 3G / 4G • Fast return to both 3G and 4G is used in Active mode, that is measurements are used wherever possible and per the table below. 72
