2g3g interworking final

WCDMA RAN SERVICE LEVEL MEASUREMENT2G <-> 3G inter-working
2G <-> 3G inter working
2G -> 3G handover PS
3G -> 2G handover PS
3G -> 2G reselection
Cell Reselection
The cell selection criteria S are defined as follows:
The cell selection criterion S for a suitable cell is fulfilled when:
Where:
Squal
Not applicable for TDD cells or GSM cells
Srxlev
Qqualmeas
FDD cells. Not applicable for TDD cells or GSM cells.
Qrxlevmeas
CPICH RSCP for FDD cells (dBm), P-CCPCH RSCP
for TDD cells (dBm) and RXLEV for GSM cells (dBm).
Qqualmin
Qrxlevmin
Pcompensation
accessing the cell on RACH (read in system information), (dBm)
P_MAX
-20dB
-115dBm
-115dBm
-115dBm
-104dBm
intra
inter
GSM
Cell Reselection
If system info in the cell indicates that HCS is not used (UseOfHCS) then for intra-freq, inter-freq and inter-system the UE shall:
If Squal > Sintrasearch, UE need not perform intra-frequency measurements.
If Squal <= Sintrasearch, perform intra-frequency measurements.
If Squal > Sintersearch, UE need not perform inter-frequency measurements
If Squal <= Sintersearch, perform inter-frequency measurements.
If Squal > SsearchRAT m, UE need not perform measurements on cells of RAT "m".
If Squal <= SsearchRAT m, perform measurements on cells of RAT "m".
* © NOKIA / OS-PS CE Nokia Expert Club ISHO / 18.10.2004
Cell Reselection
Region
Condition
1
Cell Reselection
The following cell re-selection criteria is used for intra-freq, inter-freq & inter-RAT:
Rs = Qmeas,s + Qhysts
Qhyst1
This specifies the hysteresis for serving cell that is of different radio access modes or technologies AND for serving FDD cell when cell_selection_and reselection-quality_measure is set CPICH RSCP..
Qoffset1
This specifies the offset between the two cells when the neighbour cells that are of different radio access modes or technologies AND for neighbour FDD cells when cell_selection_and reselection-quality_measure is set CPICH RSCP
Qhyst2
This specifies the hysteresis for serving FDD cell when the cell_selection_and reselection-quality_measure is set CPICH Ec/No.
Qoffset2
This specifies the offset between the two cells when neighbour FDD cells when the cell_selection_and reselection-quality_measure is set CPICH Ec/No.
Cell Reselection
CPICH RSCP (WCDMA) and RSSI (GSM)
Rs = CPICH RSCP/GSM RSSI + Qhyst1
Rn= CPICH_RSCP(n) or RXLEV(n) - Qoffset1
Rn higher in GSM cell
Yes
No
CPICH Ec/No
calculation, with
hysteresis parameter
If a TDD or GSM cell is ranked as the best cell, then the UE must perform cell re-selection to that TDD or GSM cell.
If a FDD cell is ranked as the best cell and cell_selection_and_reselection-quality_measure is set to CPICH RSCP, the UE shall perform cell re-selection to that FDD cell.
If a FDD cell is ranked as the best cell and IE cell_selection_and_reselection-quality_measure is set to CPICH Ec/No, the UE shall perform a second ranking of the FDD cells according to the R criteria using the measurement quantity CPICH Ec/No calculating the R values of the FDD cells.
If a TDD or GSM cell is ranked as the best cell, then the UE must perform cell re-selection to that TDD or GSM cell.
If a FDD cell is ranked as the best cell and cell_selection_and_reselection-quality_measure is set to CPICH RSCP, the UE shall perform cell re-selection to that FDD cell.
If a FDD cell is ranked as the best cell and IE cell_selection_and_reselection-quality_measure is set to CPICH Ec/No, the UE shall perform a second ranking of the FDD cells according to the R criteria using the measurement quantity CPICH Ec/No calculating the R values of the FDD cells.
Cell Reselection
S-Criteria OK
Cells with
Highest HCS
Cell Reselection
UE Measurements / HCS Used
When serving cell belongs to a hierarchical cell structure, the UE use Squal for FDD cells and Srxlev for TDD cells as Sx
Rules for intra- and inter-frequency measurements:
if (Srxlevs <= SsearchhHCS) OR (FDD and Sx <= Sintersearch)
UE shall measure all intra- and inter-frequency cells
else if (Sx > Sintersearch)
UE shall measure all intra and inter-frequency cells which have higher HCS priority than the serving cell.
Sintrasearch = 4dB, Sintersearch = 2dB, Slimit, searchRAT = 2dB
Ssearch_RAT = 0dB, Ssearch_HCS = 1dB, SHCS_RAT = 1dB
Squal =
Q
qualmeas
HCS_PRIO = 0 … 7;
TS 25.304 5.2.6.1
Rules for inter-RAT measurements:
UE shall measure all inter-RAT cells
else if (Sx > Slimit, SearchRATm)
UE need not to measure inter-RATm neighboring cells
else
UE shall measure all inter-RATm cells with have equal or higher HCS priority level than the serving cell.
Sintrasearch = 4dB, Sintersearch = 2dB, Slimit, searchRAT = 2dB
Ssearch_RAT = 0dB, Ssearch_HCS = 1dB, SHCS_RAT = 1dB
Cell Reselection
TS 25.304 5.2.6.1
When serving cell belongs to a hierarchical cell structure, the UE use
Squal for FDD cells and Srxlev for TDD cells as Sx
Squal =
Q
Qqualmin
Srxlev =
Q
rxlevmeas
Cell Reselection
UE Measurements / HCS Used & fast moving UE
If the number of cell reselections during time period TCRmax exceeds NCR, high-mobility has been detected.
When the number of cell reselections during time period TCRmax no longer exceeds NCR, UE shall continue these measurements during time period TCrmaxHyst.
Then, UE shall revert to measure according to the threshold based measurement rules.
TCRmax = 60s, NCR = 8, TCRmaxHyst = 0s
TS 25.304 5.2.6.1
UE measures intra-, inter-frequency, and RATm neighbouring cells, which have equal or lower HCS priority than serving cell.
Furthermore, UE shall prioritise re-selection of intra-, inter-frequency, and RATm neighbouring cells on lower HCS priority level before neighbouring cells on same HCS priority level.
Cell Reselection
Intra-frequency
3G -> 2G cell reselection
3G -> 2G Cell Reselection
Nokia Strategy: reselect to GSM early
Note: GSM cell could be 15 dB weaker
Qmeas (CPICH Ec/No)
Parameter Summary
Cell Reselection
0
NCr
8
QHCS
WCDMA: -24
Qhyst1
Qhyst1 is used for TDD and GSM cells, and for FDD cells when cell selection and re-selection quality measure is set to CPICH RSCP
4
Qhyst2
Qhyst2 is used for FDD cells when cell selection and re-selection quality measure is set to CPICH Ec/No
4
QqualMin
-20
QrxlevMin
WCDMA: -115 GSM: -105
1
Sintersearch
The threshold for inter-frequency measurements, and for the HCS measurement rules
2
Sintrasearch
The threshold for intra-frequency measurements, and for the HCS measurement rules
4
Slimit_SearchRAT
2
Ssearch_RAT
0
SsearchHCS
1
TCrmax
The duration for evaluating the allowed amount of cell reselections
60 sec
0 sec
Treselection
The UE triggers the reselection of a new cell if the cell reselection criteria are fulfilled during the time interval Treselection
0
UseOfHCS
Indicates whether the serving cell belongs to a Hierarchical Cell Structure (HCS), or not
0
2G -> 3G reselection
Cell Reselection Parameters
Qsearch_I and Qsearch_P define thresholds. The threshold value also indicates, when the measurements have to be initiated and performed. The measurements are either started, when the serving cell‘s RLA is below or above the threshold value. The default value is 15.
FDD_Qoffset and FDD_GPRS_Offset define offset values, which have to be added to the RLA of the serving and non-serving GSM cells. The result is compared with the RSCP value of the WCDMA cell. The default parameter is 0.
FDD_Qmin defines a minimum CPICH Ec/No threshold for WCDMA cell for cell re-selection.
FDD_REP_QUANT defines the reporting quantity for UTRAN cell (1=Ec/No or 0=RSCP, default: 1).
3G_Search_PRIO is used to inidicate to the MS if 3G cells can be looked for when BSIC decoding is required. (0=no, 1=yes, default: 1)
The 3G Cell Reselection list is only used by multi-RAT MSs. The system information SI2quater and SI2ter can be used to provide 3G cell information. If the two system information messages carry 3G cell information, than their lists have to be combined in the UE‘s 3G Cell Reselection list, which may then hold up to 96 UMTS cells. Up to 8 carrier frequency bands can be stored in this list, too.
Cell Reselection Measurements
Cell Reselection for Circuit Switched Services (Packet Switched Services)
A multi-RAT mobile phone reads the (GPRS) 3G Cell Reselection list, which may hold other RATs. The network controls the cell reselection measurements by the parameter Qsearch_I (Qsearch_P), which is broadcasted on the BCCH (PBCCH). The two parameters define thresholds, which tell the UE whether measurements have to be performed when the RLA_C (RLA_P) of the serving cell is below or above the threshold. GSM cell measurements are often conducted more frequently then inter-frequency measurements to save battery power.
The MS identifies and selects the best UTRAN cell, given in the (GPRS) 3G Cell Reselection list, within 30 seconds. This holds, too, when several UTRAN cells of the same frequency are listed. This time increases by 30 seconds for each additional UTRAN frequency band in the (GPRS) 3G Cell Reselection list. The time limits are only valid under good radio conditions.
In the packet transfer mode, a MS must sent the first access to the best new UTRAN cell at latest 10+x seconds. x stands for the time required to read the relevant cell system information. The time holds only, when no new GSM cell is activated and good radio conditions. The time increases by 5 seconds for each additional UTRAN carrier band listed in the GPRS 3G Cell Reselection list.
Cell Reselection Algorithm
Algorithm for cell re-selection from GSM (GPRS) to the FDD mode in UTRAN
Pre-requisite for cell re-selection to UMTS is, that UTRAN carrier bands are included in the (GPRS) 3G Cell Reselection list. If so, the MS must update
RLA_C (RLA_P) value for the serving cell and
at least 6 strongest non serving GSM cells
at least every 5 seconds. Thereafter, the MS can re-select a suitable UTRAN cell, based on the S-Criterion. If an FDD cell is suitable, following two conditions must have been met:
For a period of 5 seconds, the measured RSCP value must exceed the PLA_C (RLA_P) of the serving GSM and of all non-serving GSM cells by the value FDD_Qoffset (FDD_GPRS_Qoffset). Did a cell re-selection occur within the previous 15 seconds, the FDD_Qoffset value is increased by 5 dB.
The measured Ec/No value of the FDD cell must be greater or equal than the broadcasted value FDD_Qmin.
If the UE as performed a cell re-selection to UTRAN within the previous 5 seconds, a cell re-selection back to UTRAN is not allowed, when a suitable cell can be found within GSM.
GSM BCCH 2Quater / 2Ter
Cell Reselection List
or
If, for suitable UMTS cell
& for a period of 5 s:
CPICH RSCP > RLA_C + FDD_Qoffset
+ least 6 strongest non serving GSM cells
at least every 5 s
check
and
FDD_Qmin= -13 dB
Cell Re-selection Parameters
Range of Qsearch_I and Qsearch_P (either Below or Above values comp. to RLA_C)
Recommended value is 7 (measure always)
Range of FDD_Qoffset and FDD_GPRS_Offset
Recommended value is 0 (select always if acceptable)
0
-98
8
-78
1
2
-94
-90
9
10
-74
-70
3
-86
11
-66
4
-82
12
-62
5
-78
13
-58
6
7
-74
Always
14
15
-54
Never
R_Below
dBm
R_Upper
dBm
0
-Always
8
0
1
2
-28
-24
9
10
4
8
3
-20
11
12
4
-16
12
16
5
-12
13
20
6
7
-8
-4
14
15
24
28
Range
dBm
Range
dBm
Cell Re-selection Parameters
Range of FDD_Qmin
Recommended value is 7 (-13 dBm)
FDD_REP_QUANT defines the reporting quantity for UTRAN cell (1=Ec/No or 0=RSCP, default 1)
3G_Search_PRIO parameter allows to extend the BSIC reporting interval from 10 s to 13s by checking the BSICs from non-serving BCCH carriers and also make WCDMA measurements as often as possible. Range is 0=no, 1=yes, default value 1
Defined in the SI2quater and PSI3quater if PBCCH is allocated.
Parameter
UEs have to support new parameter range !
0
-20
1
2
-19
-18
3
-17
4
-16
5
-15
6
7
-14
-13
Range
dBm
-16dB
-16dB
-16dB
Reselection
-16dB
-16dB
-115dBm
-115dBm
-115dBm
Reselection
-115dBm
-115dBm
FMCS
Disable (0)
Enable (1)
Disable (0)
HO Control
Disable (0)
Enable (1)
Enable (1)
Enable (1)
HO Control
Enable (1)
Enable (1)
Disable (0)
Disable (0)
Disable (0)
HO Control
Disable (0)
Disable (0)
Disable (0)
Disable (0)
Disable (0)
HO Control
Disable (0)
Disable (0)
Disable (0)
Disable (0)
Disable (0)
HO Control
Disable (0)
Disable (0)
0 Reports
0 Reports
0 Reports
HO Control
0 Reports
0 Reports
0
-20dB
0
Reselection
0
0
-95dBm
-105dBm
-95dBm
33dBm
33dBm
33dBm
33dBm
33dBm
33dBm
33dBm
33dBm
33dBm
33dBm
2G Parameter
Phase 1
7 (always)
7 (always)
80%
0%
6
5
N
3
3
Cell Re-selection Example
Non GPRS case
Ec/N0
RSCP
Cell Re-selection Example
Ec/N0
RSCP
WCDMA-> GSM cell reselection
CPICH RSCP (WCDMA) and RSSI (GSM)
Rs = CPICH RSCP + Qhyst1
How to avoid ping pong ?
When phone is camped on 3G, GSM measurements can start when CPICH Ec/Io of serving cell is below Ssearch_RAT + QqualMin.
When phone is camped on GSM, cell reselection to 3G is possible if CPICH Ec/Io of the candidate is above FDD_Qmin.
Therefore, to avoid ping pongs between 3G and GSM the following condition should be met:
FDD_Qmin >= QqualMin+Ssearch_RAT
QqualMin=-18 dB
Ssearch_RAT=4 dB
3G -> 2G General handover procedure flow
ISHO Process Overview
Event Triggered Coverage/Capacity
RNC commands selected UE(s) to start
IF/IS measurements
RSSI measurements and BSIC
verification for GSM cells
Only one decision method for IS HO
5 Coverage/Capacity HO Reasons
About 25 HO parameters
(max 3) + max 6 IFHO, max 6 ISHO neighb.
Max 32 neighbours could be measured
(31 Intra-Freq neighbours)
48 Inter-Freq neighbours
3G -> 2G Handover measurement triggering
IS Handover Triggering Reasons
maximum allowed power
FMCI: IFHOcauseUplinkQuality
FMCG: GSMcauseUplinkQuality
maximum allowed power, event 6A/6D
FMCI: IFHOcauseTxPwrUL
FMCG: GSMcauseTxPwrUL
e.g. Traffic & load reason IS-HO, etc
Frequency Measuring Control for Inter-Frequency = FMCI
Frequency Measuring Control for Inter-System (GSM) = FMCG
Measurement triggering: DL Coverage
Serving
HO measurements
HHoMaxAllowedBitrateDL
Max Power on Channel
PO3
PO2
DL_CODE_PWR = power of pilot bits Power of Data Bits > 33dBm + (-3dB) + (-1dB) => Power of Data Bits > 29dBm
Signal of Data Bits (=DL_Code_PWR-PowerOffsetDLdpcchPilot) > CPICH-Power – MaxLimit on DPCH – service specific offset
PowerOffsetDLdpcchPilot = offset pilots to data (-3dB)
Primary CPICH power = 33 dBm
MAX_DL_DPCH_TXPWR (PtxDPCHmax) indicates the maximum transmission power level a base station can use on the DPCH (see Admission Control SFS [9] for more information), expressed as a relative value (dB) with respect to the primary CPICH power (dBm). (default = -3dB)
DL_DPCH_TXPWR THRESHOLD (dB) is controlled with the following inter-frequency measurement control parameters, depending on the service type (see also Packet Scheduler SFS [8]):
InterFreqDLTxPwrThrRtPS for real time packet switched services (default = -3dB)
InterFreqDLTxPwrThrNrtPS for non-real time packet switched services
InterFreqDLTxPwrThrCS for circuit switched data services (default = -3dB)
InterFreqDLTxPwrThrAMR for circuit switched voice services (default = -1dB)
For 384 kB service:
Measurement triggering: DL Coverage
RNC orders UE to make IF/IS measurements when DL TX power of a single radio link reaches threshold defined as:
DL_code_PWR -PowerOffsetDLdpcchPilot > CPICH Pwr + DL Tx Pwr + DL_TPCH_TXPWR_Threshold
DL_CODE_PWR = measured DL code power
PowerOffsetDLdpcchPilot = power offset for the DPCCH pilot bits relative to the DPDCHs power default = 3 dB, range 0...6 dB, step size 0.25 dB
DL Tx Pwr (DPCH) = measurement on DPCH Tx power, (reported by BTS)
RLMeasRepPeriod (WBTS) / default=500ms, range 0..2000ms, step 100ms
CPICH Pwr = Tx power of the CPICH of an active cell
PtxPrimaryCPICH (serving RNC) or AdjsCPICHTxPwr (drifting RNC)/33 dBm, range -10…50 dBm, step 0.1 dBm
DL_TPCH_TXPWR_Threshold = depends on the service type
FMCI: InterfreqDLTxPwrThrAMR/CS/RtPS/NrtPS -1/-3/-3/-1 dB(range -10 dB..0, step 0.5 dB)
FMCG: GSMDLTxPwrThrAMR/CS/RtPS/NrtPS -1/-3/-3/-1 dB(range -10 dB..0, step 0.5 dB)
In Addition, the DL data rate allocated to the user must not exceed
WCEL: HHoMaxAllowedBitrateDL/64 kbits/s
NOTE: Either WCDMA or GSM will be measured, not both systems
DL_CODE_PWR - PowerOffsetDLdpcchPilot >= CPICH_POWER + MAX_DL_DPCH_TXPWR + DL_DPCH_TXPWR_THRESHOLD
MAX_DL_DPCH_TXPWR indicates the maximum transmission power level a base station can use on the DPCH (see Admission Control SFS [9] for more information), expressed as a relative value (dB) with respect to the primary CPICH power (dBm)
Measurement triggering: UL Quality
1st Quality deterioration report from PC to HC inside RNC
2nd Quality deterioration report (while the condition is
satisfied the message is periodically repeated)
default 5s
EnableULQualDetRep
HHoMaxAllowedBitrateUL
RNC
Despite increasing the SIR target to the maximum allowed value the quality is poor! Need to change frequency.
Main Parameters
EnableULQualDetRep indicates whether the UL outer loop PC can send a quality deterioration report to the Handover control in situations when the quality stays worse than the BER/BLER target despite of the uplink SIR target increase.
HHoMaxAllowedBitrateUL: bit rate first has to be reduced to this level before a HO is possible
ULQualDetRepThreshold determines the time period (default 5 s) during which the quality must stay worse than the BER/BLER target (despite of uplink SIR target increase) before the UL outer loop PC may send a quality deterioration report.
In case of RT data connection (CS or PS), the maximum allocated user bitrate on the uplink DPCH must be lower than or equal to the threshold HHoMaxAllowedBitrateUL (default 32 kbits/s), before the inter-frequency handover is possible.
Measurement triggering: UL Quality
RNC starts IF/IS measurements based on UL outer-loop power control reports.
Enable reports from Outer-loop Power Control Controller to trigger IF/IS HO, RNC:EnableULQualDetRep/default 0=no, 1=yes
Time duration for which BER/BLER target has not been reached, despite SIR target at maximum level, RNC: ULQualDetRepThreshold/5 s, 0.5..5, step 0.5s
Periodic report, every RNC: ULQualDetRepThreshold seconds, while BLER/BLER target is not reached.
In addition, the UL data rate allocated to the user must not exceed WCEL: HHoMaxAllowedBitrateUL/32 kbits/s
Measurement triggering: CPICH Ec/No
Reporting event: 1E: A P-CPICH exceeds an absolute threshold (triggered if one) 1F: A P-CPICH falls below an absolute threshold (triggered if all)
time
RNC starts IF/IS measurement when event 1F occurs for all cells in the active set: A Primary CPICH becomes less than an absolute threshold
RNC stops IF/IS measurement when event 1E occurs for at least one cell of the active set : A Primary CPICH becomes better than an absolute threshold
Note:IF/IS measurements can be stopped if event 1Fs are cancelled by events 1E only when IFHO/ISHO was not successful and only inside the time between CM measurements, specified by the time InterFreqMinMeasInterval GsmMinMeasInterval/default 10s, recommendation 2s .
Filtering applied before event evaluation in the UE:
FMCS: EcNoFilterCoefficient/0= 200ms filtering period
Threshold used frequency: FMCS : HHoEcNoCancel/ -20 dB…

2g3g interworking final

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