3� ����, ���� ���� ��� ��������� ������� ����� ������3�, ������.
�������� 1. Introduction 2. Pre-requisite 3. IRAT operation 4. Key parameter of IRAT handover 5. Key parameter of Idle Mode Cell Reselection 6. Drive test introduction a. Drive test detail b. Scenario 1 – Cell reselection from WCDMA WCDMA to GSM c. Scenario 2 – IRAT Handover Handover from WCDMA to GSM d. Scenario 3 – IRAT Cell Change Change and Cell Cell Reselection from WCDMA to GSM
7. Conclusion
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������������ › This slide is to explain the 3G/2G inter-operational that Ericsson conducted in China Unicom 3G, Tai Yuan, Shan Xi province. › The slide is mainly to explain basic function, drive test cases, how does the setting impact to the IRAT handover as well as IRAT drive test samples. › The document shall provide some suggestion on the most suitable IRAT setting at the end of the document.
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2010-01-07
������������� › Prior to test on the IRAT. There are some data and information need to be checked and data consistency has played a major role in performing IRAT handover and cell reselect from WCDMA to GSM successfully. › External GSM NB defined in RNC must be consistent with BSC. Below are some of the information that we need to check: � CI � LAC � BCCH � BSIC (NCC + BCC)
› Pre-defined IRAT parameters in RNC shall be checked according.
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���� ��������� › 3G/2G inter-operationality can be mainly divided into 2 section. � Idle Mode � UE could be reselect from WCDMA to GSM in idle mode and vice versa. � Connected Mode � UE could be perform IRAT handover from WCDMA to GSM at CELL_DCH.
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2010-01-07
��� ��������� ��� ���� ���������1/4 › Below is the graph to show the Event 2d, Event 2f, and Event 3a.
Measurement Quantity (Ec/No and RSCP)
WCDMA cell
hysteresis2f/2 usedFreqTresh2fEcno usedFreqTresh2dEcno hysteresis2d/2
hysteresis2d/2
gsmTresh3a hysteresis3a/2
utranRelTresh3aEcno
GSM cell Reporting Reporting event 2d event 2f
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Reporting event 2d
6
Reporting event 3a
2010-01-07
��� ��������� ��� ���� ���������2/4 › Below are some of the key parameter involved in the IRAT handover. Parameter Name
© Ericsson AB 2010
Definition
Range
Current Setting
Default Setting
usedFreqThresh2dEcNo
Threshold for event 2d (the estimated quality of the currently used WCDMA RAN frequency is below a certain threshold). Used if measurement quantity is configured to be Ec/No.
-24 to 0
-12dB
-12dB
usedFreqThresh2dRscp
Threshold for event 2d (the estimated power level of the currently used WCDMA RAN frequency is below a certain threshold). Used if measurement quantity is configured to be RSCP.
-115 to -5
-104dBm
-100dBm
serviceOffset2dEcNo
Offset per UeRc-state that is added to the 2d, 2f, 3a and 2b Ec/No thresholds. Coverage trigger offset per UeRc.
-20 to 20
Speech=0, PS=-2, HS=-20
0
serviceOffset2dRSCP
Offset per UeRc-state that is added to the 2d, 2f, 3a and 2b Ec/No thresholds. Coverage trigger offset per UeRc.
-50 to 50
Speech=0, PS=-3, HS=0
0
hysteresis2d
Hysteresis used for event 2d.
0 to 14.5dB
0dB
0dB
timetotrigger2dEcNo
Interval time between detection of event 2d and sending of the measurement report, when the measurement quantity is CPICH EC/NO. If event 2d condition is fulfilled during at least a time greater than or equal to timeToTrigger2dEcno milliseconds, then event 2d occurs. A setting of 5000 disables the 2d Ec/No measurement.
0, 10, 20,…, 320,…., 5000ms
320ms
320ms
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��� ��������� ��� ���� ���������3/4 Parameter Name
© Ericsson AB 2010
Definition
hysteresis2f
Hysteresis used for event 2f.
timetotrigger2fEcno
Interval time between detection of event 2f and sending of the measurement report, when the measurement quantity is CPICH EC/NO. If event 2f condition is fulfilled during at least a time greater than or equal to timeToTrigger2fEcno milliseconds, then event 2f occurs.
Range
Current Setting
Default Setting
0 to -14.5
0dB
0dB
0; 10; 20;……. 1280;…. 2560,.
1280ms
1280ms
5000 ms
usedfreqRelThresh2fEcno
Relative threshold for event 2f versus event 2d. The estimated quality of the currently used WCDMA RAN frequency is above a certain threshold + usedFreqThresh2dEcno .
0 to 20
2dB
2dB
usedfreqRelThresh2fRscp
Relative threshold for event 2f versus event 2d. The estimated quality of the currently used WCDMA RAN frequency is above a certain threshold + usedFreqThresh2dRscp
0 to 20
3dB
3dB
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��� ��������� ��� ���� ���������4/4 Parameter Name
Definition
Range
Current Setting
Default Setting
utranRelThresh3aEcno
Relative threshold for event 3a versus event 2d (the estimated quality of the currently used WCDMA RAN frequency is below a certain threshold + usedFreqThresh2dEcno and the estimated quality of the GSM system is above a certain threshold in the same time interval) for WCDMA RAN, when the 2d measurement quantity is CPICH Ec/No.
-10 to 10
0dB
-1dB
utranRelThresh3aRscp
Relative threshold for event 3a versus event 2d (the estimated power level of the currently used WCDMA RAN frequency is below a certain threshold + usedFreqThresh2dRscp and the estimated power level of the GSM carrier is above a certain threshold in the same time interval) for WCDMA RAN, when the 2d measurement quantity is CPICH RSCP.
-20 to 20
0dB
-3dB
gsmThresh3a
Threshold for event 3a (the estimated quality of the currently used WCDMA RAN frequency is below a certain threshold and the estimated quality of the GSM system is above a certain threshold) for GSM.
-115 to 0
-95dBm
-95dBm
0dB
0dB
100ms
100ms
hysteresis3a timetotrigger3a
Hysteresis used for event 3a. Interval time. If event 3a condition is fulfilled during at least a time greater than or equal to timeToTrigger3a milliseconds, then event 3a occurs.
0 to 7.5dB 0; 10; 20;.. 100;… 1280;… 2560;…. 5000 ms
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Ericsson Internal
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2010-01-07
��� ��������� ��� ���� ������������1/2 › Below is the graph to show the threshold for cell reselection from GSM to WCDMA.
© Ericsson AB 2010
Ericsson Internal
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2010-01-07
��� ��������� ��� ���� ������������2/2 › This is the cell reselection parameter during idle mode. Parameter Name
Definition
Range
Current Setting
Default Setting
qQualmin
Minimum required quality level in the cell measured in the UE. The parameter is defined per serving cell and per WCDMA neighbor.
-24..0 [step 1dB]
-18dB
-18dB
qRxlevmin
Minimum signal strength level received in the UE. The parameter is defined per serving cell and per WCDMA neighbor and GSM neighbor.
-115..25; 100 (not sent)
-115dBm
-115dBm
sRatsearch
Decision on when measurements on GSM neighbors are performed which is made using this parameter in relation with Squal. The parameter is defined per cell.
-32..20
4dB
4dB
qHyst1s
Hysteresis value of the serving cell to be used for cell ranking.
0..40
4dB
4dB
qOffset1n
Signal strength offset between source and target cell to be used for cell ranking based on CPICH RSCP or EcNo. The parameter is defined per WCDMA neighbor relation and per GSM neighbor relation.
-50..50
0dB
0dB
treSelection
Reselection time control of cell selection and reselection. The time-to-trigger for cell reselection
0..31
2s
2s
occurs in seconds. The parameter is defined per cell.
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2010-01-07
����� ���� ������������
����� ���� ������ There are 3 scenario drive tests shall be done on idle mode, connected mode on CS and PS services respectively: › Idle mode to reselect from WCDMA to GSM. › CS12.2 drive test from WCDMA site towards IRAT border. › HSDPA PS call was done from WCDMA site to the IRAT border area.
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2010-01-07
����� ����� ������ › Blue arrow line to show the direction of the IRAT handover and idle mode cell reselection tests were carried out. › The drive route was located along 太茅路 from 小店 south bound to 桥家大院。
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�������� 1� ���� ���� ���� ����������� ���� ����� �� ��� � 1/2
› Sratsearch was configured at 0dB, it can be found from SIB3, Layer3 messages. › Idle mode cell reselection from WCDMA happened at EcNo = -21dB.
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Ericsson Internal
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2010-01-07
�������� 1� ���� ���� ���� ����������� ���� ����� �� ��� � 2/2
› Sratsearch was configured at 4dB, it can be found from SIB3, Layer3 messages. › Idle mode cell reselection from WCDMA happened at EcNo = -15.5dB.
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Ericsson Internal
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2010-01-07
�������� 2� ���� �������� ���� ����� �� ��� � 1/3
Measurement control
› › › › ›
Drive test was carry out with the parameter setting; usedfreqthresh2dEcno = -12dB, usedfreqthresh2dRscp = -104dBm that were configured at the tested utrancells. Event2d triggered at EcNo=-12dB . Event3a occurs at EcNo=-12.5dB , RSCP=-102dBm. From measurement report, the gsm-Carrier RSSI has recorded -66dBm. Targeted GSM with ARFCN@CH113 to be IRAT handover from WCDMA at event3a has fulfilled better than gsmthresh3a = 95dBm, and worse than usedFreqThresh2dEcno+ utranRelThresh3aEcno = -12+0dB = -12dB.
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2010-01-07
�������� 2� ���� �������� ���� ����� �� ��� � 2/3 Measurement control
› › › › ›
Drive test was carry out with the parameter setting; usedfreqthresh2dEcno = -16dB, usedfreqthresh2dRscp = -100dBm that were configured at the tested utrancells. Event2d triggered at RSCP=-100dBm . Event3a occurs at EcNo=-12.5dB , RSCP=-99dBm. From measurement report, the gsm-Carrier RSSI has recorded -74dBm. Targeted GSM with ARFCN@CH113 to be IRAT handover from WCDMA at event3a has fulfilled better than gsmthresh3a = 95dBm, and worse than usedFreqThresh2dRscp+ utranRelThresh3aRscp = -100+0dBm = -100dBm.
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Ericsson Internal
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2010-01-07
�������� 2� ���� �������� ���� ����� �� ��� � 3/3 Measurement control
› › › › › ›
Drive test was carry out with the parameter setting; usedfreqthresh2dEcno = -12dB, usedfreqthresh2dRscp = -100dBm that were configured at the tested utrancells. Event2d triggered at EcNo=-102dBm . Event3a occurs at EcNo=-13.5dB , RSCP=-101dBm. From measurement report, the gsm-Carrier RSSI has recorded -69dBm. Targeted GSM with ARFCN@CH113 to be IRAT handover from WCDMA at event3a has fulfilled better than gsmthresh3a = -95dBm, and worse than usedFreqThresh2dEcno+ utranRelThresh3aEcno = -12+0dB = 12dB. Multiple IRAT handover failure were encountered due to IRAT physical channel failure.
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Ericsson Internal
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2010-01-07
�������� 3� ���� ���� ������ ���� ����� �� ���� � 1/2 Measurement control
› › › › › ›
Drive test was carry out with the parameter setting; usedfreqthresh2dEcno = -12dB, usedfreqthresh2dRscp = 104dBm, serviceOffset2dEcNo=-2dB for PS, -20dB for HS and serviceOffset2dRscp=-3dB. Event2d triggered at EcNo=-12dB . Event3a occurs at EcNo=-13dB , RSCP=-102dBm. From measurement report, the gsm-Carrier RSSI has recorded -75dBm. Targeted GSM with ARFCN@CH113 to be IRAT handover from WCDMA at event3a has fulfilled better than gsmthresh3a = -95dBm, and worse than usedFreqThresh2dEcno+ utranRelThresh3aEcno = -12+0dB = -12dB. IRAT Cell Change has been triggered mainly due to parameter’ poorqualitydetected = ON
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Ericsson Internal
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2010-01-07
�������� 3� ���� ���� ������ ���� ����� �� ���� � 2/2 Measurement control
› Drive test was carry out with the parameter setting; usedfreqthresh2dEcno = -16dB, usedfreqthresh2dRscp = -100dBm, serviceOffset2dEcNo=-2dB for PS, -20dB for HS and serviceOffset2dRscp=-3dB. › Neither Event2d nor Event3a triggered due to HS was not suppose to handover to GPRS due to the strategy required by China Unicom. › Finally, UE goes to idle mode and cell reselection to GPRS. › GPRS was initiated at GSM with ARFCN 113, BSIC 33. › IRAT Cell Change does not occurs due to parameter’ poorqualitydetected = OFF © Ericsson AB 2010
Ericsson Internal
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2010-01-07
���������� With the multiple combination of the drive test setting either in idle mode, or connected mode. It is recommended to configure the below setting for smooth IRAT handover transition, better overall network throughput and as well as network KPI. › Recommend to configure Sratsearch = 4 › usedfreqthresh2dEcno = -12dB › usedfreqthresh2dRscp = -104dBm › Mobility phase 2: HStoDchTrigger: poorqualitydetected = OFF It is recommended to switch OFF the poorqualitydetected parameter mainly to provide the better DL throughput to the subscriber while mobilised, to improve the PS DCR as not every UE was support the HS downswitch to Cell_DCH due to poorqualitydetected feature enabled.
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Ericsson Internal
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