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8/10/2019 60523609 NSN 2G 3G Parameter Setting
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1 NSN Siemens Networks Presentation / Author / Date
I insert classification level
Sharing Traffic 2G-3G
Load Base Handover 2G-3GCell Reselection
3G-2G
2G-3G
PUSH AMR
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Soc Classification level
Load based Handover GSM -> WCDMA
100%
80%
0%
Load reasonHandoversfor speech
Load of GSM cell
Packet Data to WCDMAregardless of GSM load
Speech to WCDMAonly with high GSM load
Higher bit ratesfor data users
More capacityfor speech
Packet BCCH parameters can be usedto push GPRS mobiles to WCDMA
Utran
HoThScTpdc
= 80%
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Soc Classification level
GSM
GSM
Load & Coverage Reason Handover
GSM
GSM highloaded
WCDMA lowloaded
GSM GSM
WCDMA WCDMA
Load reasonHandover for speech
and for HSCSD
WCDMA GSM
Load reasonHandover
Coverage reasonHandover
WCDMA can be usedto relieve GSM overload
GSM can be used to extendWCDMA coverage area
Mobile moving
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Soc Classification level
Load based Handover Process: GSM-> WCDMA
Handover Triggering Thresholds set in BSC
Inter-RAT measurements starts in caseThe RXLEVof the serving cell is above orbelow the given threshold Qsearch_C
Handover Decisionis done in case of
Load of the serving cell > Load_Threshold
& CPICH Ec/No> min Ec/No Threshold
MS selects the target UTRAN cell based
on measurement results
Handover command is send to MSC
MS is measuring the UTRAN cells continuouslyif they are defined as a neighbor ,
The number of GSM neighbor reported could be 3-6depending on the set value of parameterFDD_MULTIRAT_REPORT(0,1,2=def,3).
The load is measured in the cell level by comparing
the occupied TCHs to the available TCHs (20 s
interval used)
Load Threshold for Speech Calls or Transparent Data
inter-RAT Handover:
utranHoThScTpdc(Min Traffic Load TDHO),default = 80%
minEcnoThreshold(Min CPICH EC/NO
Threshold), default15 dB
Parameters are sent from the BSC to the mobilein the Measurement Information message
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ISHO 2G -> 3G Parameters
Parameter Specification name NSN parameter Range Default value
min traffic load for speech call LOAD_THRESHOLD_FOR
_SC_IS_HO
utranHoThScTpdc (LTSC) 0-100% 80%
minimum CPICH Ec/Io level MIN_ECNO_THRESHOLD minEcnoThreshold
(MET)
-240.5 dB -15 dB
min interval between unsucc ISHO
attempt
MIN_INTERVAL_BETWEE
N_UNSUCC_ISHO_ATTE
MPT
minIntUnsuccIsHo (UMIU) 0255 s 3 s
threshold for multi-RAT MS Qsearch_C qSearchC (QSRC) 015 15 (never)
rec. 7 (always)
Specification name Parameter explanation Value range Note
FDD_REP_QUANT Indicates the reporting quantity for UTRAN
FDD cells
0=RSCP,
1=EC/NO
Not tunable,
Fixed value 1
3G_SEARCH_PRIO Indicates if 3G cells may be searched when
BSIC decoding is required
0 = no,
1 = yes
Not tunable,
Fixed value 1
FDD_MULTIRAT_REPORTING The number of cells from the access
technology/mode FDD that shall be includedin the measurement report
03 Not tunable,
Fixed value 2
Qsearch_C_Initial Indicates the Qsearch value to be used in
connected mode before Qsearch_C is
received
0 = use Qsearch_I,
1 = (always)
Not tunable,
Fixed value 0
Changeable
Hidden
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Soc Classification level
Handover Control
GSM ISHO
Load Based Handover to WCDMA Cell Reselection
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Cell Reselection 3G -> 2G
First ranking of all the cells based onCPICH RSCP (WCDMA) and RSSI (GSM)
Rs = CPICH RSCP + Qhyst1Rn= Rxlev(n) - Qoffset1
Rn (GSM) > Rs (WCDMA)And
Rxlev (GSM) >QrxlevMin
YesNo
Cell re-selectionto GSM
Neighbour WCDMA or GSM
cell calculation with offsetparameter
Serving WCDMA cellcalculation, with
hysteresis parameter
UE starts GSM measurements ifCPICH Ec/No < qQualMin+ sSearchRAT
SintraSearch
SinterSearch
SsearchRAT
CPICH EcNo
qQualMin
Second ranking only for WCDMAcells based on CPICH Ec/No
Rs = CPICH Ec/No + Qhyst2Rn=CPICH_Ec/No(n)-Qoffset2 Cell re-selection to
WCDMA cell of highestR value
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Cell Reselection 3G -> 2G
UE ranks the serving cell and the measured neighboring cells to find out if
reselection should be madeAll the measured suitable cells (S-criteria) are included in the ranking.
Criteria for a suitable cell (S-criteria) is defined as
WCDMA intra-frequency neighbor cell:
CPICH Ec/No > AdjsQqualminand CPICH RSCP > AdjsQrexlevmin
WCDMA inter-frequency cell:
CPICH Ec/No > Adj iQqualminandCPICH RSCP > Adj iQrexlevmin
GSM cell:
Rxlev > Qrxlevmin
Ranking is done using Criteria R, and the UE reselects to the cell with highest R-
criteria. R-criteria is defined as:
For serving cell: Rs = Qmeas,s+ QhystsFor neighboring cell Rn = Qmeas,nQoffsetts,n
Qmeas is CPICH Ec/No for WCDMA cell and RxLev for GSM cell
GSM measurements can start when CPICH Ec/Io of serving cell is below Ssearch_RAT+ QqualMin
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Soc Classification level
GSM MS starts WCDMA measurements if:RLA_C< F(Qsearch_I) for 0
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Cell Re-selection Parameters
Qsearch_Iand Qsearch_Pdefine the threshold for non-GPRS/GPRS (respectively) capable
UEs to measure 3G neighbour cells when a running average of the received downlink
signal level (RLA_C) of the serving cell is below (0-7) or above (8-15) the threshold
Value 0 1 6 7 8 9 10 14 15
dBm -98 -94 -74 Always
-78 -74 -70 -54 Never
FDD_QoffsetandFDD_GPRS_Offsetthe non-GPRS/GPRS (respectively) capable UEsadd this offset to the RLA_C of the GSM cells. After that the UE compares the
measured RSCP values of 3G cells with signal levels of the GSM cells
Value 0 1 2 3 8 14 15
dBm -always -28 -24 -20 0 24 28
Always selectirrespective of RSCPvalue
Reselect in case RSCP >GSM RXLev (RLA_C)+28dB
If RLA_C < -94 UE starts3G measurements
UE always measures 3Gcells
If RLA_C > -70 UE starts3G measurements
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RLA_C
Cell Re-selection Example: weaker WCDMANon GPRS case
t
Serving GSM Cell
Neighbour WCDMA Cell
Ec/NoRSCP/RLA_C
5 sec.
Cell re-selection to WCDMA
FDD_Qmin=0-12 dB
FDD_Qoffset= -8 dB
Qsearch_I =-98 dBm
Measurements starts (serving cell)
Minimum Quality Requirement for WCDMA
Ec/N0
RSCP
GSM -> WCDMA
CPICH RSCP> RLA_C+ FDD_Qoffset&
CPICH Ec/No FDD_Qmin
Idle Mode
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Soc Classification level
Cell Re-selection Example: stronger WCDMAGPRS case
t
Serving GSM Cell (Best)
Neighbour WCDMA Cell
Ec/NoRSCP/RLA_C
5 sec.
Cell re-selection to WCDMA
FDD_Qmin= -20 dB
FDD_GPRS_Qoffset= 8 dB Qsearch_P
= -98 dBm
RLA_P
Measurements starts (serving cell)
Minimum Quality Requirement for WCDMA
Ec/N0
RSCP
Connected Mode
GSM -> WCDMA
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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
CPICH Ec/Io
FDD_Qmin >= -12dB
QqualMin +Ssearch_RAT
t
Camping on 3G Camping on GSM Camping on 3G
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Soc Classification level
PUSH AMR
Push Voice 3G-2G
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Soc Classification level
max. al lowed UE Tx Power(e.g. 21 dBm)+
GsmUETxPwrThrAMR:
FMCG; -60..0; 1; -3 dBhere: - 60 dB !
Forced Handover for AMR Voice Call
Feature can be used to push3G AMR calls to 2G
Extreme parameter setting for ISHO
trigger cause UE Tx power (event 6A)
WCDMA
GSM
AMR voice call setup in 3G
forced handover
to GSM
[..]UE RNC
RRC: RadioBearerSetup
RRC: RadioBearerSetupComplete
RRC: MeasurementControl
RRC: MeasurementReport (event 6A)
FMCG: GSMcauseTxPwrUL
FMCG: GsmUETxPwrThrAMR
ISHO measurements & HO
to GSM
UE immediately answers
with Measurement Report
push means Handover, not Directed-Retry !
Remember:
6A:UE Tx power >
absolute threshold
GSMcauseTxPWRUL FMCG; 0 (no) /1 (yes)
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THANKS