10_RA4121AEN40GLA0_Idle Mode Mobility (Without Inter Sys Mobility)

Idle Mode Mobility LTE Radio Parameters RL40

1

© Nokia Siemens Networks

RA4121AEN40GLA0

Contents 1. LTE Functionalities & Features Overview 2. Parameters Structure & SIBs 3. Physical Channel Configuration & Random Access 4. UE State Handling 5. Bearer Management 6. Admission Control 7. Power Control & Power Setting 8. Adaptive Modulation & Coding 9. MIMO Mode Control 10. Idle Mode Mobility 11. Connected Mode Mobility 12. Scheduler 13. SON 4


RA4121AEN40GLA0

Index • • • • •

Measurements in LTE Cell Selection Cell Reselection Mobility States Intra LTE Mobility • Intra Frequency Mobility • Inter Frequency Mobility

• Inter RAT Mobility • LTE to UTRAN • LTE to GSM • LTE to CDMA 2000

5


RA4121AEN40GLA0

LTE Measurements Intra LTE measurements ( from LTE to LTE) • UE measurements – CQI measurements – Reference Signal Received Power (RSRP) – Reference Signal Received Quality (RSRQ) • eNB measurements – Non standardized (vendor specific): TA, Average RSSI, Average SINR, detected PRACH preambles, transport channel BLER – Standardized: DL RS Tx Power, Received Interference Power, Thermal Noise Power Measurements from LTE to other systems • UE measurements are mainly intended for handover. – UTRA FDD: CPICH RSCP, CPICH Ec/No and carrier RSSI – GSM: GSM carrier RSSI – UTRA TDD: carrier RSSI, RSCP, P-CCPCH – CDMA2000: 1xRTT Pilot Strength, HRPD Pilot Strength 6


RA4121AEN40GLA0

UE Measurements: RSRP & RSRQ RSRP (Reference Signal Received Power) • Average of power levels (in [W]) received across all Reference Signal symbols within the considered measurement frequency bandwidth.

• UE only takes measurements from the cell-specific Reference Signal elements of the serving cell, this makes RSRP results load and MIMO/diversity independent. If receiver diversity is in use by the UE, the reported value shall not be lower than the corresponding RSRP of any of the individual diversity branches

Received Signal Strength Indicator (RSSI) • RSSI comprises the linear average of the total received power (in [W]) observed only in OFDM symbols containing reference symbols for antenna port 0, in the measurement bandwidth, over N number of resource blocks by the UE from all sources, including co-channel serving and non-serving cells, adjacent channel interference, thermal noise etc.

RSRQ (Reference Signal Received Quality) • Defined as the ratio N×RSRP/(E-UTRA carrier RSSI), where N is the number of RBs of the E-UTRA carrier RSSI measurement bandwidth. The measurements in the numerator and denominator shall be made over the same set of resource blocks 7


RA4121AEN40GLA0

Index • • • • •


• Inter RAT Mobility • LTE to UTRAN • LTE to GSM • LTE to CDMA 2000

8


RA4121AEN40GLA0

Cell Selection Procedure 1) UE creates a candidate list of potential cells to camp on. Two possible search procedures: • Initial Cell Selection: UE scans all RF channels to find a suitable cell. On each carrier, the UE searches for the strongest cell and reads information. Once the UE has found the suitable cell for the selected PLMN, the UE creates a candidate list consisting of this cell and its neighboring cells as received in measurement control information. • Stored Information Cell Selection (optionally) This procedure requires information stored from previously received measurement control information elements (cell parameters, carrier frequencies, etc.). After the UE has found a suitable cell for the selected PLMN, candidate list is created same as the initial cell selection process. 2) Each cell on the candidate list is evaluated according to the selection criteria S 3) After selecting a suitable cell (S criterion fulfilled) for camp on, UE reports this event to NAS for registration procedures. If the registration is successful, the UE enters into "camped normally“ state.

Initial Selection - Carrier 1: strongest cell - Carrier 2: strongest cell - Carrier i ….. Stored Information Selection - Previous information - Previous detections 9


RA4121AEN40GLA0

S – Criterion Cell Selection UE selects a eUTRA cell if the S (selection) criteria is fulfilled: Srxlev > 0 Srxlev = Qrxlevmeas – (Qrxlevmin* + Qrxlevminoffset**) - Pcompensation UE measurement (RSRP)

SIB1 Parameter

SIB1 Parameter

Pcompensation = max (PEMAX*** – PUMAX, 0) (dB) SIB1 Parameter

qrxlevmin

* Qrxlevmin = LNCEL: qrxlevmin ** Qrxlevminoffset = LNCEL: qRxLevMinOffset (used only when camped in VPLMN) *** PEMAX = LNCEL: pMaxOwnCell PUMAX is UE class specific max. UL Tx power

Minimum required RSRP level LNCEL; -140…-44dBm; 2dBm; -

qRxLevMinOffset Affects minimum required RSRP level LNCEL; 2..16 dB; 2dB; -

pMaxOwnCell Used to calculate Pcompensation LNCEL; -30..34dBm; 1dBm; *PUMAX: UE class specific max. UL Tx power; 23 dBm 10


RA4121AEN40GLA0

S – Criterion Cell Selection

Cell size defining parameters: • Qrxlevmin

I am outside





I am inside, but have not enough power

pMaxOwnCell

Pcompensation = max(P_MAX_OWN_CELL – PUMAX, 0)

Used to calculate Pcompensation LNCEL; -30..33dBm; 1dBm; -

*PUMAX: UE class specific max. UL Tx power; 23 dBm 11


RA4121AEN40GLA0

Index • • • • •


12


RA4121AEN40GLA0

Parameter Objects Structure for Reselection

LNBTS LNCEL IAFIM CDFIM IRFIM GFIM

UFFIM GNFL IAFIM = Intra Frequency Idle Mode IRFIM = Inter Frequency Idle Mode UFFIM = UTRAN FDD Idle Mode GFIM = GERAN Frequency Idle Mode GNFL = GERAN Neighbor Frequency List CDFIM = CDMA2000 Frequency Idle Mode 13


RA4121AEN40GLA0

Reselection Process Overview UE is measuring the neighbor cells only when the RSRP signal level is below some threshold. The measurements trigger is based primarily on absolute priorities. In case of equal priority additional thresholds are defined

Measurements trigger

Evaluate cell reselection criteria “R”

Execute cell reselection

14


RA4121AEN40GLA0

For the reselection there are different cases depending on priorites of the neighbor frequency Layers (for inter-frequency and inter-RAT)

Priority Layer Concept in LTE • • • • • • •

15

Cell reselection between different LTE frequencies and different RATs is based on priorities Priorities could be configured for each LTE frequency (including serving cell) and for each frequency of each RAT Priorities are provided to UE via system information Equal priorities are not applicable for inter-RAT cell reselection UE performs only cell reselection evaluation for inter-LTE frequency and interRAT carriers for which the UE has a priority UE is camped on a cell which defines the priorities for the other network layers The range of absolute priorities is 0..7 (0 is the lowest priority) LNCEL: cellReSelPrio

Absolute priority of the serving cell

IRFIM: eutCelResPrio

Absolute priority of EUTRA carrier frequency

UFFIM: uCelResPrio

Absolute priority of the UTRA carrier frequency

GNFL: gCelResPrio

Absolute priority of the GERAN carrier frequency

CDFIM: hrpdCResPrio

Absolute priority of the CDMA2000 HRPD carrier frequency

CDFIM: rttCResPrio

Absolute priority of the CDMA2000 1xRTT carrier frequency


RA4121AEN40GLA0

Measurements Trigger - Intra Frequency • When to trigger the measurements of neighbor cells? • UE is not continuously measuring neighbor cells in search of a better cell to camp on • UE only performs intra frequency measurements when:

Intra - Frequency:

sIntrasearch LNCEL; 0..62dB; 2dB; -

Srxlev <= Sintrasearch → Qrxlevmeas ≤ Qrxlevmin + Sintrasearch (assuming that qRxLevMinOffset is not used)

16


RA4121AEN40GLA0

qrxlevmin Minimum required RSRP level LNCEL; -140…-44dBm; 2dBm; -

Measurements Trigger – Inter-frequency and InterRAT (1/2) • In the case of inter-frequency and inter-RAT reselection the measurements trigger depends primarily on the absolute priorities of the serving & non-serving layer • UE should always measure higher priority layers • Therefore UE searches for higher priority layers at least once every (60xNlayers) seconds • Nlayers is the total number of higher priorities LTE and 3G layers • Nlayers is increased by 1 if there is one or more groups of GSM frequencies with higher priority.

IF cellReSelPrio(inter-f or inter-RAT) > cellReSelPrio(serving) THEN the measurements of the neighbor cell are mandatory IF cellReSelPrio(inter-f or inter-RAT) <= cellReSelPrio(serving) THEN the measurements are performed when RSRP of the serving cell is below some threshold: Srxlev <= Snonintrasearch sNonIntrsearch LNCEL; 0..62dB; 2dB; → Qrxlevmeas ≤ Qrxlevmin + Snonintrasearch (assuming that qRxLevMinOffset is not used) 17


RA4121AEN40GLA0

Measurements Trigger – Inter-frequency and InterRAT (1/2)

sNonIntrsearch LNCEL; 0..62dB; 2dB; 18


RA4121AEN40GLA0

Reselection Process Overview UE is measuring the neighbor cells only when the RSRP signal level is below some threshold. The measurements trigger is based primarily on absolute priorities. In case of equal priority addotional thresholds are defined

Measurements trigger

Evaluate cell reselection criteria “R”

Execute cell reselection

19


RA4121AEN40GLA0

For the reselection there are different cases depending on priorites of the neighbor frequency Layers (for inter-frequency and inter-RAT)

R Criterion – Cell Reselection Intra-frequency Case (1/2) •

Once the measurements for neighbor cells have been triggered the UE will rank the measured cells which fulfill the S- Criterion according to the R- Criterion qHyst LNCEL; 0dB (0),…,24dB (15); • Cell ranking criterion: Rs = Qmeas,s + Qhyst,s qOffsetCell IAFIM; -24 dB (0),…,24 dB (30); - ; 0 Rn = Qmeas,n – Qoffset,n dB(15)

Rn > Rs “cell reselection“

tReselEutr LNCEL; 0…7s; 1s; -

Where: Qmeas,s & Qmeas,n = RSRP

• The UE shall reselect the new cell, if the following conditions are met: • 1. The new cell is better ranked than the serving cell during a time interval tReselection • 2. More than 1 second has elapsed since the UE has camped on the current serving cell

20


RA4121AEN40GLA0

Note: s – indicates the serving cell n – indicates the candidate neighbour cell.

R Criterion – Cell Reselection Intra-frequency Case (2/2)

Qmeas

Rs = Qmeas,s + Qhysts Rn = Qmeas,n - Qoffsets,n

Rn > Rs => „cell reselection“

qHyst

Qmeas,n

LNCEL; 0dB (0)… 24dB (15); -

Rn

Qmeas,s Qhysts

qOffsetCell IAFIM; -24 dB (0)… 24 dB (30); - ; 0 dB(15)

Rs

Qoffsets,n Treselection tReselEutr LNCEL; 0…7s; 1s; 21


RA4121AEN40GLA0

Time

R Criterion – Cell Reselection Inter-frequency Equal Priority Case • Similar to intra-frequency case • An additional frequency offset to control the reselection is introduced: LTE f2 Rs = Qmeas,s + Qhyst Rn = Qmeas,n – Qoffset Rn > Rs “cell reselection“ offset = 0 dB LTE f1

• Where:

Qmeas,s & Qmeas,n = RSRP Qoffset = qOffCell,n + Qoffsetfrequency qOffFrq

qOffCell

Frequency specific offset for equal priority EUTRAN frequencies IRFIM; -24..24; 2; 0 dB

Cell specific offset IRFIM; -24..24; 1; - dB

22


RA4121AEN40GLA0

LTE f2 offset = -2 dB LTE f1

R Criterion – Cell Reselection Reselection to a Higher Priority LTE frequency • The reselection to a higher absolute priority LTE layer is performed if: SnonServingCell > Threshx,high

interFrqThrH Threshx,high

• Where:

IRFIM; 0..62dB; 2dB; -

SnonServingCell = Qrxlevmeas – Qrxlevmin - Pcompensation qRxLevMinInterF Min. coverage criteria

• Qrxlevmeas = RSRP of the LTE frequency layer IRFIM;-140..-44dBm; 2dB; • Qrxlevmin specified by the parameter qRxLevMinInterF → Qrxlevmeas(nonServingCell) > qRxLevMinInterF + interFrqThrH (Assuming Pcompensation = 0)

• The criteria above must be satisfied for a time period equal to Treselection

interTResEut Reselection timer IRFIM; 0..7s; 1s; -

23


RA4121AEN40GLA0

R Criterion – Cell Reselection Reselection to a Lower Priority LTE frequency • Reselection to a lower priority LTE Layer is performed if: interFrqThrL

SservingCell < Thresoldserving,low AND SNonServingCell > Threshx,low

Threshx,low IRFIM; 0..62dB; 2dB; -

threshSrvLow

• Which means:

Thresholdserving,low LNCEL; 0..62dB; 2dB; -

→ Qrxlevmeas(ServingCell) < qRxLevMin + thresholdSrvLow

AND Qrxlevmeas(NonServingCell) > qRxLevMinInterF + interFreqThrL (assuming that qRxLevMinOffset is not used and Pcompensation = 0) qrxlevmin

qRxLevMinInterF

Minimum required RSRP level

Min. coverage criteria

LNCEL; -140…-44dBm; 2dBm; -

IRFIM;-140..-44dBm; 2dB; -

Threshx,high > Threshx,low > Thresserving,low 24


RA4121AEN40GLA0

Index • • • • •


25


RA4121AEN40GLA0

Mobility States • Possible mobility states are: high, medium & normal mobility speed UE’s. • For faster moving UEs the procedure alters - speed dependent scaling rules are applied. tEvaluation

• UE state detection:

nCellChgHigh LNCEL; 1..16; 1; -

LNCEL; 30s (0), 60s (1), 120s (2), 180s (3), 240s (4) ; -

– If the number of (different cells) cell reselections during the past time period tEvalulation exceeds nCellChgHigh, high mobility has been detected.

– If the number exceeds nCellChgMed, and not nCellChgHigh, medium mobility has been detected.

– Else Normal Mobility is considered – REMARK: Mobility could be further applied separately for intra, inter frequency, interRAT scenarios

.

nCellChgMed LNCEL; 1..16; 1; -

26


RA4121AEN40GLA0

Mobility States • For High & medium mobility states, cell ranking criteria will be modified to consider a scaling factor:

qHystSfHigh LNCEL; -6 dB (0), -4 dB (1), -2 dB (2), 0 dB (3); -

• High mobility: •

Multiply Qhyst by "Speed dependent ScalingFactor for Qhyst for high mobility state“ (qHystSfHigh)

•

Multiply tReselection by "Speed dependent ScalingFactor for TreselectionRAT for high mobility state for RAT cells. (RAT = EUTRAN, UTRAN, GERAN). (celResTiFHM) celResTiFHM qHystSfMed

•Medium mobility:

LNCEL; -6 dB (0), -4 dB (1), -2 dB (2), 0 dB (3); -

•

Multiply Qhyst by "Speed dependent ScalingFactor for Qhyst for medium mobility state“ (qHystSfMed)

•

Multiply tReselection by "Speed dependent ScalingFactor for TreselectionRAT for medium mobility state for RAT cells. (RAT = EUTRAN, UTRAN, GERAN). (celResTiFMM) celResTiFMM LNCEL; 0.25 (0), 0.5 (1), 0.75 (2), 1 (3); -

27

LNCEL; 0.25 (0), 0.5 (1), 0.75 (2), 1 (3); -


RA4121AEN40GLA0

Index • • • • •


28


RA4121AEN40GLA0

Idle Mode Mobility LTE Intra-Frequency (1/4) •

Broadcast of SIB 4 is optional – no need to broadcast any intrafrequency neighbor cells – UE is able to complete cell re-selection with SIB3 information

•

eUTRAN SIB4 informs about LTE idle mode neighbors – Physical Cell Identifier (PCI) of neighbor cell can be broadcast – cell (neighbor) individual re-select offset can be broadcast

•

SIB4 also informs about blacklisted cells (BC) – A UE is not allowed to re-select a blacklisted cell – Up to 16 groups of cells (PCIs) can be blacklisted – UE will not measure BC cells in connected mode •

UE will never be instructed from eNB to handover to a blacklisted cell

physCellIdNcl PCI is a unique cell identification in a neighboring cell list IAFIM; 0…503; 1; 29


RA4121AEN40GLA0

qOffsetCell IAFIM; -24 dB(0)… 24 dB (30); 0dB (15)

Idle Mode Mobility LTE Intra-Frequency (2/4) Black Listed Cells –> the feature prohibit UE to camp on group of cells

– – – – – –

UE shall not consider Black Listed Cells to camp on Operator can control Black Cell List Range of blacklisted cells must be consecutive Range can be defined with parameter IAFIM: rangeIntraPci Start of range can be defined with parameter IAFIM: startIntraPci PCI is Physical Cell Identifier Black Cell List startIntraPci rangeIntraPci

IAFIM; 0…503; 1; -

IAFIM; n4 (0), n8 (1), n12 (2), n16 (3), n24 (4), n32 (5), n48 (6), n64 (7), n84 (8), n96 (9), n128 (10), n168 (11), n252 (12), n504 (13), Not Used (14) ;-

0 30


rangeIntraPci

startIntraPci

PCI Range RA4121AEN40GLA0

503

Idle Mode Mobility LTE Intra-Frequency (3/4) SIB 4 Parameter structure of IAFIM Object: – IAFIMId Identifies IAFIM managed object – intrFrBCList (structure: 2 parameters)  rangeIntraPCI Indicates the number of PCIs in the range  startIntraPCI Indicates the lowest PCI in the range

x 16 Black Cell List

– intrFrNCList (structure: 2 parameters)  physCellIdNcl The Physical Cell Identifier is a unique cell identification in a Neighboring Cell List  qOffsetCell The parameter defines a cell-specific offset (in dB) that is used in the cell reselection procedure. IAFIM = Intra Frequency Idle Mode Parameters 31


RA4121AEN40GLA0

x 16

Idle Mode Mobility LTE Intra-Frequency (4/4) Neighbor cell list – copy from eNB SCF file

8 PCIs are blacklisted

1 regular intra-frequency neighbors defined

32


RA4121AEN40GLA0

Idle Mode Mobility LTE Inter-Frequency (1/2) SIB5 IRFIM Object Parameters • irfimId 8 frequency layers could be defined • dlCarFrqEut f2 Frequency number • eutCelResPrio relative cell prio for ranking

x8

• intFrBCList (structure: 2 parameters per neighbor) – rangeInterPci – startInterPci

x 16

• intFrNCList (structure: 2 parameters per neighbor) – physCellIdNcl – qOffCell • interFrqThrH • interFrqThrL

x 16

33


RA4121AEN40GLA0

Idle Mode Mobility LTE Intra-Frequency (2/2) SIB5 IRFIM Object Parameters

e.g. interTResEut

• interPresAntP Antenna port 1 used* • interTResEut • measBdw f2 Bandwidth • pMaxInterF • qOffFrq Frequency specific offset • qRxLevMinInterF minimum coverage criteria

E-UTRA Cell Reselection Timer IRFIM; 0 – 7s; 1; -

measBdw Max. allowed BW for neighbors IRFIM; 6, 15, 25, 59, 75, 100 mbw; -

pMaxInterF Pmax to be used in neighb. EUTRA cells on this frequency IRFIM; -33..33; 1; -

• tResEutSF (structure: 2 parameters) – eutResTiFHM – eutResTiFMM

* True  all neighbor cells are applying at least 2 cell specific Antenna Ports 34


RA4121AEN40GLA0

mbw: Resource Blocks

10_RA4121AEN40GLA0_Idle Mode Mobility (Without Inter Sys Mobility)

Recommend Documents