ZTE - Fast Return to LTE
Short Description
Description of feature functionalities...
Description
Fast Return to LTE Feature Guide
Fast Return to LTE
Fast Return to LTE Version V1.00
Date
2015/08/03
Author
Feng Hong
Reviewer
Wang Juntao
Notes
Compared with UR13, add section 3.2, 3.3 and 3.6, update section 6.2~6.4 Deleted reserved parameter GREspare1
V1.10
2015/11/19
Liu Fulei
Wang Juntao
2 bit14, added URncInfo.csmtIdentifySw ch 1.
Chapter 3.1.1: Add “CSFB Identified by RRC Connection Requests Is Categorized as CS Service ”
V1.20
2016/02/19
Liu Fulei
Wang Juntao
2.
Add “3.1.7 Special Scenario that C SFB Users are Forbidden to Fast
Return to LTE”. 3.
Add 3.1.8 Supplementary Services Forbidden to Fast Return to LTE
© 2016 ZTE Corporation. All rights reserved. ZTE CONFIDENTIAL: This document contains proprietary information of ZTE and is not to be disclosed or used without the prior written permission of ZTE. Due to update and improvement of ZTE products and technologies, information in this document is subjected to change without notice.
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TABLE OF CONTENTS 1
Feature Attribute ............................................................................................... 6
2 2.1 2.1.1
Overview Overview ................................. ................................................. ................................. .................................. .................................. ......................... ........ 6 Feature Introduction ............................................................................................. 6 ZWF21-03-111 Fast Return to LTE ...................................................................... 6
2.1.2 2.1.3 2.2 2.3
ZWF21-03-112 Packet Packet Service Fast Return to LTE for Inactive Mode ................. ................ . 7 ZWF21-03-113 Packet Service Fast Return to LTE for Active Mode .................. ........ ............ .. 8 License License Control Control ................................. ................................................. .................................. .................................. ................................. ................. 8 Correlation With Other Features .......................................................................... 8
3 3.1 3.1.1 3.1.2 3.1.3 3.1.4
Technical Description ....................................................................................... 9 ZWF21-03-111 Fast Return to LTE ...................................................................... 9 Identification of of CSFB Users and SRVCC Users.................. ......... ................... ................... .................. ........... .. 10 EUTRAN Supporting Judgement ....................................................................... 11 Fast Return in PS Handover Mode .................................................................... 11 Fast Return in Redirection Mode based on Measurement .................. ......... ................... ................ ...... 15
3.1.5 3.1.6 3.1.7 3.1.8 3.2
Fast Return in Redirection Mode without without Measurement .................. ......... .................. ................... .......... 19 Fast Return Strategy of IUR ............................................................................... 26 Special Scenario that CSFB Users are Forbidden to Fast Return to LTE ........... ......... .. 27 Supplementary Supplementary Services Forbidden to Fast Return to LTE ................... ......... ................... .............. ..... 27 ZWF21-03-112 Packet Packet Service Fast Return to LTE for Inactive Mode ............... 28
3.2.1 3.2.2 3.3 3.3.1 3.3.2
Strategy without Dedicated Priority .................................................................... Strategy with Dedicated Priority ......................................................................... ZWF21-03-113 Packet Service Fast Return to LTE for Active Mode .................. ........ .......... Strategy without Dedicated Priority .................................................................... Strategy with Dedicated Priority .........................................................................
3.4 3.4.1 3.4.2 3.5 3.5.1 3.5.2
Penalty strategy ................................................................................................. 32 Penalty Mechanism Principle ............................................................................. 32 Penalty on UE Flag ............................................................................................ 33 EUTRAN Frequency Priority .............................................................................. 33 Frequency Priority Configuration ........................................................................ 33 Frequency Priority Strategy in Handover/Redirection Handover/Redirection ................... ......... ................... .................. ............. .... 34
3.5.3 3.6
Relationship with Dedicated Priority ................................................................... 35 Optimization of Redirection to LTE Strategy for Only PS Signaling .................. ......... ........... .. 35
4 4.1
Paramete Parameters rs................................ ................................................. .................................. .................................. .................................. .................... ... 36 ZWF21-03-111 Fast Return to LTE .................................................................... 36
4.2 4.3 4.4
ZWF21-03-112 Packet Packet Service Fast Return to LTE for Inactive Mode ............... 42 ZWF21-03-113 Packet Service Fast Return to LTE f or Active Mode .................. ........ .......... 43 EUTRAN Frequency Priority .............................................................................. 44
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5 5.1 5.1.1 5.1.2
Related Counters and Alarms ........................................................................ 47 Related Counters ............................................................................................... 47 ZWF21-03-111 Fast Return to LTE .................................................................... 47 ZWF21-03-112 Packet Service Fast Return to LTE for Inactive Mode ............... 47
5.1.3 5.2
ZWF21-03-113 Packet Service Fast Return to LTE for Active Mode .................. 48 Related Alarms .................................................................................................. 48
6 6.1 6.2 6.2.1
Engineering Guide .......................................................................................... 48 Application Scenario .......................................................................................... 48 Feature Activation Procedure ............................................................................. 49 Fast Return to LTE............................................................................................. 49
6.2.2 6.2.3 6.2.4 6.3
Packet Service Fast Return to LTE for Inactive Mode ........................................ 59 Packet Service Fast Return to LTE for Active Mode ........................................... 60 EUTRAN Frequency Priority .............................................................................. 61 Feature Validation Procedure ............................................................................ 63
6.3.1 6.3.2 6.3.3 6.3.4 6.4 6.5
Fast Return to LTE for CSFB ............................................................................. 63 Pack Service Fast Return to LTE for Inactive Mode ........................................... 64 Packet Service Fast Return to LTE for Active Mode ........................................... 65 Fast Return to LTE with Dedicated Priority for CSFB ......................................... 65 Feature Deactivation Procedure......................................................................... 66 Impact on the Network ....................................................................................... 67
6.5.1 6.5.2 6.5.3
ZWF21-03-111 Fast Return to LTE .................................................................... 67 ZWF21-03-112 Packet Service Fast Return to LTE for Inactive Mode ............... 67 ZWF21-03-113 Packet Service Fast Return to LTE for Active Mode .................. 68
7
Abbreviation .................................................................................................... 68
8
Reference Document....................................................................................... 69
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FIGURES Figure 6-1
Parameters configuration interface 1 ................................................................49
Figure 6-2
Parameters configuration interface 2 ................................................................50
Figure 6-3
Parameters configuration interface 3 ................................................................50
Figure 6-4
Parameters configuration interface 4 ................................................................51
Figure 6-5
Parameters configuration interface 5 ................................................................52
Figure 6-6
Parameters configuration interface 6 ................................................................52
Figure 6-7
Parameters configuration interface 7 ................................................................53
Figure 6-8
Parameters configuration interface 8 ................................................................53
Figure 6-9
Parameters configuration interface 9 ................................................................54
Figure 6-10
Parameters configuration interface 10 ............................................................54
Figure 6-11
Parameters configuration interface 11 ............................................................55
Figure 6-12
Parameters configuration interface 12 ............................................................55
Figure 6-13
Parameters configuration interface 13 ............................................................56
Figure 6-14
Parameters configuration interface 14 ............................................................57
Figure 6-15
Parameters configuration interface 15 ............................................................57
Figure 6-16
Parameters configuration interface 16 ............................................................58
Figure 6-17
Parameters configuration interface 17 ............................................................59
Figure 6-18
Parameters configuration interface 18 ............................................................60
Figure 6-19
Parameters configuration interface 19 ............................................................61
Figure 6-20
Parameters configuration interface 20 ............................................................62
Figure 6-21
Parameters configuration interface 21 ............................................................63
TABLES Table 2-1
License Control List ............................................................................................ 8
Table 5-1
Counter List .......................................................................................................47
Table 6-1
Feature Validation Procedure 1..........................................................................63
Table 6-2
Feature Validation Procedure 2..........................................................................64
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Table 6-3
Feature Validation Procedure 3..........................................................................65
Table 6-4
Feature Validation Procedure 4..........................................................................65
Table 6-5
RNC Parameter List ...........................................................................................66
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1
Feature Attribute BSC/RNC version: [ZXWR RNC V3.14.10.14/ZXUR 9000 V4.14.10.14] BTS/Node B version: [ZXSDR V4.14.10] Attribute: [Optional] Involved NEs: NE Name
Related or Not
MS/UE
-
BTS/Node B
-
BSC/RNC
√
iTC
-
MSC
-
MGW
-
SGSN
-
GGSN
-
HLR
-
Special Requirement
“√”: involved “-”: not involved
2
Overview
2.1
Feature Introduction
2.1.1
ZWF21-03-111 Fast Return to LTE The LTE network without IMS element cannot provide voice service for the UE. The UE needs to establish the voice service after being transferred to the 3G network through the CSFB method. During the voice service release, if there is no any other service, the UE returns to the idle state after releasing the RRC connection, reads the UTRAN broadcast information, and probably needs another location area update. After that, the UE
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performs cell selection/reselection estimation, and returns to the LTE network under the control of the E-UTRAN cell reselection parameter. ZTE RAN fill s the “Redirect info” information in the RRC release message of the voice service, and the UE searches the LTE neighboring cell of the specific frequency without reading the UTRAN cell broadcast and location area update procedures, reducing the time cost by the UE to return to the LTE network. The data service of a UMTS/LTE dual mode terminal is possibly kept in the UMTS network. For example, PS data is ongoing after CS call is released for a CS fallback user, or a data service is transferred from LTE to UMTS at th e edge of LTE coverage. The data service is kept in the UMTS network in a long period when the data traffic is always active. This is not acceptable by both the operator and the subscriber. LTE network is new deployed and taken as a more advanced network. The operator prefers to utilize LTE network as much as possible. And the subscriber also wishes to experience service in it. To avoid the subscriber staying in UMTS network f or a long period, ZTE RAN triggers the subscriber to switch to LTE network when it is in the coverage of E-UTRAN cell.
2.1.2
ZWF21-03-112 Packet Service Fast Return to LTE for Inactive Mode If a 4G subscriber initials only PS data in 3G, when the data transmission is inactive, normally 3G RAN switches it to Cell PCH/URA PCH or IDLE. In the control of cell reselection parameters broadcast in 3G cell, the subscriber camps in LTE finally. However, some procedure such as reading the whole 3G cell system information, search LTE cells one by one indicated in SIB19 of 3G cell are required. With the feature, 3G RAN releases RRC connection of the subscriber and redirects it to LTE. It makes the terminal searching LTE target directly. It accelerates the subscriber back to LTE.
If the feature “ZWF27-02-002 User Dedicated Frequency Priority” is switched off, 3G RAN redirects or hand over the UE to LTE according to neighbor relation. Otherwise the UE is redirected or handover to LTE only when LTE is the highest priority according to the mapping of SPID to dedicated frequency priority. And the LTE frequency is provided to UE according the priority in dedicated frequency priority configuration.
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2.1.3
ZWF21-03-113 Packet Service Fast Return to LTE for Active Mode If a 4G subscriber establish PS data in 3G, he may stay in 3G in a long period when watching video or serving as a Wifi hotspot. With the feature, ZTE RAN identifies such subscriber and redirects him/her to LTE network.
If the feature “ZWF27-02-002 User De dicated Frequency Priority” is switched off, 3G RAN redirects or hand over the UE to LTE according to neighbor relation. Otherwise the UE is redirected or handover to LTE only when LTE is the highest priority according to the mapping of SPID to dedicated frequency priority. And the LTE frequency is provided to UE according the priority in dedicated frequency priority configuration.
2.2
License Control This feature is under license control. It must have authorization on the OMC or LMT before the configuration of the feature.
Table 2-1
License Control List
Feature ID
ZWF21-03-111
ZWF21-03-112
Feature Name
Service
Return
to
LTE
ZWF21-03-113
Service
Return
to
Active Mode
2.3
LTE
rol Item
NE
LTE
Fast for
Inactive Mode Packet
Configured
Fast Return to
Fast Return to LTE Packet
License Cont
Fast for
Fast Return to LTE
Fast Return to LTE
Unit
RNC
RNC
RNC
RNC
RNC
RNC
Correlation With Other Features 1. Required Features ZWF21-03-101 CS Fallback from LTE Support ZWF21-03-120 SR-VCC
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2. Mutually Exclusive Features None 3. Affected Features None
3
Technical Description
3.1
ZWF21-03-111 Fast Return to LTE When the UTRAN and EUTRAN are jointly deployed, the UE in EUTRAN can be handed over to the UTRAN through the CSFB or SRVCC. To provide these UEs better service experience, the UTRAN transfers these UEs to the EUTRAN through PS handover or redirection. The application scenario is described as follows:
The UE in the LTE cell initiates a voice call. Due to CSFB, the UE can be handed over from LTE to UMTS. When the CS call of the UE is released in the UMTS network, the RNC performs the fast return to LTE strategy.
The UE establishes PS service in EUTRAN, and initiates a CS call. The UE is handed over from LTE to UMTS due to CSFB. When the CS call of the UE is released in UMTS, the RNC performs the fast return to LTE strategy.
The UE establishes a VoLTE service in EUTRAN. If the signaling quality of the UE is getting worse, the SRVCC from LTE to UMTS is triggered. When the CS call of the UE is released in UMTS, the RNC performs the fast return to LTE strategy.
The UE establishes a VoLTE service and a PS service in EUTRAN. If the signaling quality of the UE is getting worse, the SRVCC from LTE to UMTS is triggered. When the CS call of the UE is released in UMTS, the RNC performs the fast return to LTE strategy.
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When the PS service channel switching from CELL_DCH to CELL_FACH for a UE is triggered in UMTS, the RNC performs the fast return to LTE strategy.
This document describes the fast return to LTE strategy that is applicable to t he following scenarios:
3.1.1
Fast return in PS Handover mode
Fast return in redirection mode based on measurement
Fast return in redirection mode without measurement
Identification of CSFB Users and SRVCC Users If any of the following conditions is satisfied, the UE shall be identified as a CSFB UE. 1.
The “CSFB Indication” is carried in the RRC Connection Request message, or
2.
Neither the “CSFB Indication” nor the “Pre-redirection info”(3GPP R9.4) is carried in the RRC Connection Request message, the time difference between the RRC Connection Request message and first RAB Assignment Request message for a CS service is not greater than URncInfo.csfbIdentifyTimer , or
3.
The “CSFB Information” is carried in “Source RNC to Target RNC Transparent
Container” of the Relocation Request message , or 4.
The RNC receives a IU RELEASE COMMAND message with IE “End of CSFB” (3GPP R10.4), or
5.
“CSMO” is carried in the NAS message “ CM SERVICE REQUEST” analyzed by the RNC, or
6.
“CSMO” is carried in the NAS message “ LOCATION UPDATING REQUEST” analyzed by the RNC, or
7.
“CSMT” is carried in the NAS message “LOCATION UPDATING REQUEST” analyzed by the RNC.
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If CSFB is identified by RRC Connection Requests and the Establishment Cause is
not any of “Originating Conversational Call , Terminating Conversational Call,
Emergency Call” , then the Establishment Cause of CSFB is modified as Originating Conversational Call.
If the following conditions are satisfied, the UE shall be identified as a SRVCC UE.
3.1.2
1.
ULogicalRnc.rncSrvccSw is set to “On”;
2.
The UE is relocated from the EUTRAN to UMTS and includes a CS service.
EUTRAN Supporting Judgement EUTRAN service handover IE is not “ Handover to EUTRAN shall not be performed ”,
1.
it indicates that handover or redirection to LTE is allowed. 2.
3.1.2.1
UE Capability supports LTE.
Identification of UE Capability and Special Handling For the relocation from other RNCs to the l ocal RNC, UE capability is only acquired in the way that RNC sends the UE CAPABILIT Y ENQUIRY message. When the RNC identifies the CSFB Information IE in the Relocation Request message, and does not acquire UE capability, if the switch URncInfo.ueLteCapJugSw is “1: On”, the UE is taken for supporting
LTE
(Support
of
E-UTRA
FDD/TDD).
Otherwise,
the
switch
URncInfo.ueLteCapJugSw is “0: Off”, the UE is not taken for supporting LTE.
3.1.3
Fast Return in PS Handover Mode Whether enabling the dedicated priority functionality affects the judgment on triggering fast return to LTE. See the details in the following chapters.
3.1.3.1
Strategy without Dedicated Priority
CSFB
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1.
The process of the PS Service when a CS service is released for Multi-RAB Service After the UE is handed over from EUTRAN to UTRAN due to CSFB, if the CS service is released for Multi-RAB, and if the following conditions are met, the
EUTRAN’s compressed mode is activated, and the inter -RAT measurement for the EUTRAN is configured. After the measurement reports are received, the PS handover procedure is performed and the UE is handed over to EUTRAN. i.
The EUTRAN neighboring cells exist.
ii.
The UE supports the PS handover from UMTS to EUTRAN.
iii.
URncInfo.cheEutraCapiSw is “Off”. Or URncInfo.cheEutraCapiSw is “On” and the UE E-UTRA Capability IE is obtained.
iv.
URncFunction.fastRetEUtranSwch is “On”.
v.
UCelInfoFDD.csfbMulSrv2LteSw
is
“Handover
judgment
Based
on
Measurement”. vi.
URncInfo.csfbPsHo2LteMode is “PS handover”.
SRVCC
1.
The process of the PS Service when a CS service is released for Multi-RAB Service After the UE is handed over from EUTRAN to UTRAN due to SRVCC, if the CS service is released for Multi-RAB, and if the following conditions are satisfied, the
EUTRAN’s compressed mode is activated, and the inter -RAT measurement for the EUTRAN is configured. After measurement reports are received, the PS handover procedure is performed and the UE is handed over to the EUTRAN. i.
The EUTRAN neighboring cells exist.
ii.
The UE supports the PS handover from UMTS to EUTRAN.
iii.
URncInfo.cheEutraCapiSw is “Off”. Or URncInfo.cheEutraCapiSw is “On” and the UE E-UTRA Capability IE is obtained.
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iv.
URncFunction.fastRetEUtranSwch is “On”.
v.
UCelInfoFDD.srvccMulSrv2LteSw
is “Handover judgment Based on
Measurement”. vi.
URncInfo.srvccPsHo2LteMode is “PS handover”.
Note: 1.
UCelInfoFDD.simCompUserNum is used to control the number of users activating compressed mode for fast return to EUTRAN based on measurement, to avoid affecting system performance. If the current number of the UEs
to be activated
with compressed mode due to fast return to EUTRAN in the cell is not less than UCelInfoFDD.simCompUserNum, the compressed mode for the UEs due to fast return to EUTAN will not be activated. Otherwise, the compressed mode for the UEs due to fast return to EUTAN will be activated. 2.
If the compressed mode is activated due to fast return to EUTRAN, the timer URncInfo.psHoLteMeasTimer is enabled. When the timer expires, if Event (3C) of the UE is not reported, the RNC determines whether the compressed mode of the UE is deactivated based on the current signal quality.
3.1.3.2
Strategy with Dedicated Priority When
user
dedicated
frequency
priority(ULogicalRnc.dePriRncSwch
and
UExtCelInfoFDD.dePriSwch) is on, the related strategy is as follows:
CSFB
1.
The process of the PS Service when a CS service is released for Multi-RAB Service After the UE is handed over from EUTRAN to UTRAN due to CSFB, if the CS service is released for Multi-RAB, and if the following conditions are met, the
EUTRAN’s compressed mode is activated, and the inter -RAT measurement for the EUTRAN is configured. After the measurement reports are received, the PS handover procedure is performed and the UE is handed over to EUTRAN. i.
The UE supporting EUTRAN neighboring cells exist.
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ii.
The UE supports the PS handover from UMTS to EUTRAN.
iii.
URncInfo.cheEutraCapiSw is “Off”. Or URncInfo.cheEutraCapiSw is “On” and the UE E-UTRA Capability IE is obtained.
iv.
URncFunction.fastRetEUtranSwch is “On”.
v.
UCelInfoFDD.csfbMulSrv2LteSw
is
“Handover
judgment
Based
on
Measurement”. vi.
URncInfo.csfbPsHo2LteMode is “PS handover”.
vii.
The highest priority of EUTRAN frequencies is higher than the highest priority of UTRAN frequencies. The frequency and priority acquires from MO_UDePri,
and the detailed strategy and parameters refer to “ZTE UMTS User Dedicated Frequency Priority Feature Guide”.
SRVCC
1.
The process of the PS Service when a CS service is released for Multi-RAB Service After the UE is handed over from EUTRAN to UTRAN due to SRVCC, if the CS service is released for Multi-RAB, and if the following conditions are satisfied, the
EUTRAN’s compressed mode is activated, and the inter -RAT measurement for the EUTRAN is configured. After measurement reports are received, the PS handover procedure is performed and the UE is handed over to the EUTRAN. i.
The UE supporting EUTRAN neighboring cells exist.
ii.
The UE supports the PS handover from UMTS to EUTRAN.
iii.
URncInfo.cheEutraCapiSw is “Off”. Or URncInfo.cheEutraCapiSw is “On” and the UE E-UTRA Capability IE is obtained.
iv.
URncFunction.fastRetEUtranSwch is “On”.
v.
UCelInfoFDD.srvccMulSrv2LteSw
is
“Handover
judgment
Based
on
Measurement”.
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vi.
URncInfo.srvccPsHo2LteMode is “PS handover”.
vii.
The highest priority of EUTRAN frequencies is higher than the highest priority of UTRAN frequencies. The frequency and priority acquires from MO_UDePri,
and the detailed strategy and parameters refer to “ZTE UMTS User Dedicated Frequency Priority Feature Guide”.
3.1.4
Fast Return in Redirection Mode based on Measurement Whether enabling the dedicated priority functionality affects the judgment on triggering fast return to LTE and the frequency filling criteria in IE “Redirection Info”. See the details in the following chapters.
3.1.4.1
Strategy without Dedicated Priority
CSFB
1.
The process of the PS Service when a CS service is released for Multi-RAB Service After the UE is handed over from EUTRAN to UTRAN due to CSFB, if the CS service is released for Multi-RAB, and if the following conditions are satisfied, the EUTRAN compressed mode is activated, and the inter-RAT measurement for the EUTRAN is configured. After the measurement reports are received, the Redirection procedure is performed, and downlink central frequency information of the EUTRAN cell whose quality meets inter-RAT measurement event is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN. i.
The EUTRAN neighboring cells exist.
ii.
URncFunction.fastRetEUtranSwch is “On”.
iii.
UCelInfoFDD.csfbMulSrv2LteSw
is
“Handover
judgment
Based
on
Measurement”. iv.
URncInfo.csfbPsHo2LteMode is “Redirection”, the UE supports the EUTRAN measurement; or URncInfo.csfbPsHo2LteMode is “PS handover”, the UE does
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not support the PS handover from UMTS to EUTRAN but supports the EUTRAN measurement.
SRVCC
1.
The process of the PS Service when the CS service is released for Multi-RAB Service After the UE is handed over from EUTRAN to UTRAN due to SRVCC, if the C S service is released for Multi-RAB, and if the following conditions are satisfied, the RNC activates the EUTRAN compressed mode, and configures the inter-RAT measurement. After the measurement reports are received, the RNC performs the Redirection procedure, and fills downlink central frequency information of the EUTRAN cell whose quality meets inter-RAT measurement event in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN. i.
The EUTRAN neighboring cells exist;
ii.
URncFunction.fastRetEUtranSwch is “On”;
iii.
UCelInfoFDD.srvccMulSrv2LteSw
is “Handover judgment Based on
Measurement”; iv.
URncInfo.srvccPsHo2LteMode is “Redirection”, the UE supports the EUTRAN measurement; or URncInfo.srvccPsHo2LteMode is “PS handover”, the UE does not support PS handover to EUTRAN but the EUTRAN measurement.
Note: 1.
UCelInfoFDD.simCompUserNum is used to control the number of users to be activated with compressed mode for fast return to EUTRAN based on measurement to avoid affecting system performance. If the current number of the UEs who has been activated compressed mode due to fast return to EUTRAN is not less than UCelInfoFDD.simCompUserNum, the compressed mode for the UEs due to fast return to EUTAN will not be activated. Otherwise, the compressed mode for the UEs due to fast return to EUTAN will be activated.
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2.
If the compressed mode is activated due to fast return to EUTRAN, the timer URncInfo.psHoLteMeasTimer is is initialized. When the timer expires, if Event (3C) of the UE is not reported, the RNC will judge whether the compressed mode of the UE is deactivated based on the current signal quality.
3.1.4.2
Strategy with Dedicated Priority When
user
dedicated
frequency
priority (ULogicalRnc.dePriRncSwch priority(
and
UExtCelInfoFDD.dePriSwch)) is on, the related strategy is as follows: UExtCelInfoFDD.dePriSwch
CSFB
1.
The process of the PS Service when a CS service is released for Multi-RAB Service After the UE is handed over from EUTRAN to UTRAN due to CSFB, if the CS service is released for Multi-RAB, and if the following conditions are satisfied, the EUTRAN compressed mode is activated, and the inter-RAT measurement for the EUTRAN is configured. After the measurement reports are received, the Redirection procedure is performed, and frequency satisfying the conditions is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN. i.
The UE supporting EUTRAN neighboring cells exist.
ii.
URncFunction.fastRetEUtranSwch is “On”.
iii.
UCelInfoFDD.csfbMulSrv2LteSw
is
“Handover
judgment
Based
on
Measurement”. iv.
URncInfo.csfbPsHo2LteMode is “Redirection”, the UE supports the EUTRAN measurement; or URncInfo.csfbPsHo2LteMode is “PS handover”, the UE does not support the PS handover from UMTS to EUTRAN but supports the EUTRAN measurement.
v.
The highest priority of EUTRAN frequencies is higher than the highest priority of UTRAN frequencies. The frequency and priority acquires from MO_UDePri,
and the detailed strategy and parameters refer to “ZTE UMTS User Dedicated Frequency Priority Feature Guide”.
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SRVCC
1.
The process of the PS Service when the CS service is released for Multi-RAB Service After the UE is handed over from EUTRAN to UTRAN due to SRVCC, if the CS service is released for Multi-RAB, and if the following conditions are satisfied, the RNC activates the EUTRAN compressed mode, and configures the inter-RAT measurement. After the measurement reports are received, the RNC performs the Redirection procedure, and fills downlink central frequency information of the EUTRAN cell who meets “Redirection Condition” in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN. i.
The UE supporting EUTRAN neighboring cells exist.
ii.
URncFunction.fastRetEUtranSwch is “On”;
iii.
UCelInfoFDD.srvccMulSrv2LteSw
is “Handover judgment Based on
Measurement”; iv.
URncInfo.srvccPsHo2LteMode is “Redirection”, the UE supports the EUTRAN measurement; or URncInfo.srvccPsHo2LteMode is “PS handover”, the UE does not support PS handover to EUTRAN but the EUTRAN measurement.
v.
The highest priority of EUTRAN frequencies is higher than the highest priority of UTRAN frequencies. The frequency and priority acquires from MO_UDePri,
and the detailed strategy and parameters refer to “ZTE UMTS User Dedicated Frequency Priority Feature Guide”. Note: Definition of frequency satisfying the conditions: Frequency set1 consists of UE reporting EUTRAN frequency, and frequency set2 consists of EUTRAN frequency configured in MO_UDePri. If frequency set1 and set2 have common frequency, then it adds this frequency to frequency set3. And the RNC fills the frequency in set3 with highest dedicated priority in
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RRC Connection Release. If several frequency have the same highest dedicated priority, then RNC fills 4 FDD frequencies and 4 TDD frequencies at most.
3.1.5
Fast Return in Redirection Mode without Measurement Whether enabling the dedicated priority functionality affects the judgment on triggering fast return to LTE and the frequency filling criteria in IE “Redirection Info”. See the details in the following chapters.
3.1.5.1
Strategy without Dedicated Priority
CSFB
1.
The process of the PS Service when the CS service is released for Multi-RAB Service After the UE is handed over from EUTRAN to UTRAN due to CSFB, if the CS service is released for Multi-RAB, and if the following conditions are satisfied, the EUTRAN cell downlink central frequency information is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN. i.
The EUTRAN neighboring cells exist.
ii.
URncFunction.fastRetEUtranSwch is “On”.
iii.
UCelInfoFDD.csfbMulSrv2LteSw
is
“Handover
judgment
Based
on
Measurement”. The UE neither supports the PS handover from UMTS to EUTRAN nor the EUTRAN measurement, but only supports EUTRAN (Support
of
E-UTRA
FDD/TDD).
Alternatively,
UCelInfoFDD.csfbMulSrv2LteSw is “Redirection without Measurement”, the UE supports EUTRAN (Support of E-UTRA FDD/TDD). 2.
The process of only CS Service After the UE is handed over from EUTRAN to UTRAN due to CSFB, if the CS service is released for Single-RAB, and if the following conditions are satisfied, the EUTRAN cell downlink central frequency information is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN.
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3.
i.
The EUTRAN neighboring cells exist.
ii.
The UE supports the EUTRAN (Support of E-UTRA FDD/TDD).
iii.
URncFunction.fastRetEUtranSwch is “On”.
iv.
UtranCellFDD.csfbCsRel2LteSw is “On”.
CS Service Establishment Failure
After the UE is handed over from EUTRAN to UTRAN due to CSFB, if the IU Release Command message of CS domain is received, and if the following conditions are satisfied, the EUTRAN cell downlink central frequency information is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN.
-
PS services exist i.
The EUTRAN neighboring cells exist.
ii.
URncFunction.fastRetEUtranSwch is “On”.
iii.
UCelInfoFDD.csfbMulSrv2LteSw
is
“Handover
Judgment
Based
on
Measurement”. The UE neither supports the PS handover from UMTS to EUTRAN nor the EUTRAN measurement, but only supports EUTRAN (Support
of
E-UTRA
FDD/TDD).
Alternatively,
UCelInfoFDD.csfbMulSrv2LteSw is “Redirection without Measurement”, the UE supports EUTRAN (Support of E-UTRA FDD/TDD).
-
PS services do not exist i.
The EUTRAN neighboring cells exist.
ii.
The UE supports the EUTRAN (Support of E-UTRA FDD/TDD).
iii.
URncFunction.fastRetEUtranSwch is “On”.
iv.
UtranCellFDD.csfbCsRel2LteSw is “On”.
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SRVCC
1.
The process of the PS Service when the CS service is released for Multi-RAB Service After the UE is handed over from EUTRAN to UTRAN due to SRVCC, if the CS service is released for Multi-RAB, and if the following conditions are satisfied, the EUTRAN cell downlink central frequency information is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN. i.
The EUTRAN neighboring cells exist.
ii.
URncFunction.fastRetEUtranSwch is “On”.
iii.
UCelInfoFDD.srvccMulSrv2LteSw
is
“Handover
judgment
Based
on
Measurement”, and the UE neither supports PS handovers to EUTRAN nor the EUTRAN measurement, and the UE only supports EUTRAN (Support of E-UTRA FDD/TDD). OR UCelInfoFDD.srvccMulSrv2LteSw is “Redirection
without Measurement”, and the UE supports EUTRAN (Support of E-UTRA FDD/TDD). 2.
The process of only CS Service After the UE is handed over from EUTRAN to UTRAN due to SRVCC, if the CS service is released for Single-RAB, and if the following conditions are satisfied, the
EUTRAN cell’s downlink central frequency information is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN.
i.
The EUTRAN neighboring cells exist.
ii.
The UE supports EUTRAN (Support of E-UTRA FDD/TDD).
iii.
URncFunction.fastRetEUtranSwch is “On”.
iv.
UtranCellFDD.srvccCsRel2LteSw is “On”.
The process of channel switching from CELL_DCH to CELL_FACH
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If the PS service channel switching from CELL_DCH to CELL_FACH is triggered in UMTS, and if the following conditions are satisfied, the EUTRAN cell downlink central frequency information is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN. i.
The EUTRAN neighboring cells exist.
ii.
The UE supports EUTRAN (Support of E-UTRA FDD/TDD).
iii.
URncFunction.fastRetEUtranSwch is “On”.
iv.
UCelInfoFDD.dch2FachRetLteSw is “On”.
Note: 1.
When the condition of fast return to LTE is fulfilled, the RNC acquires UE supporting frequencies from EUTRAN neighboring relation, then fills 4 FDD and 4 TDD frequencies in RRC Connection Release.
3.1.5.2
Strategy with Dedicated Priority When
user
dedicated
frequency
priority
(ULogicalRnc.dePriRncSwch
and
UExtCelInfoFDD.dePriSwch) is on, the related strategy is as follows:
CSFB
1.
The process of the PS Service when the CS service is released for Multi-RAB Service After the UE is handed over from EUTRAN to UTRAN due to CSFB, if the CS service is released for Multi-RAB, and if the following conditions are satisfied, the EUTRAN cell downlink central frequency information is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN. i.
The UE supporting EUTRAN neighboring cells exist.
ii.
URncFunction.fastRetEUtranSwch is “On”.
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iii.
UCelInfoFDD.csfbMulSrv2LteSw
is
“Handover
Judgment
Based
on
Measurement”. The UE neither supports the PS handover from UMTS to EUTRAN nor the EUTRAN measurement, but only supports EUTRAN (Support
of
E-UTRA
FDD/TDD).
Alternatively,
UCelInfoFDD.csfbMulSrv2LteSw is “Redirection without Measurement”, the UE supports EUTRAN (Support of E-UTRA FDD/TDD). iv.
The highest priority of EUTRAN frequencies is higher than the highest priority of UTRAN frequencies. The frequency and priority acquires from MO_UDePri,
and the detailed strategy and parameters refer to “ZTE UMTS User Dedicated Frequency Priority Feature Guide”. 2.
The process of only CS Service After the UE is handed over from EUTRAN to UTRAN due to CSFB, if the CS service is released for Single-RAB, and if the following conditions are satisfied, the EUTRAN cell downlink central frequency information is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN. i.
The UE supporting EUTRAN neighboring cells exist.
ii.
The UE supports the EUTRAN (Support of E-UTRA FDD/TDD).
iii.
URncFunction.fastRetEUtranSwch is “On”.
iv.
UtranCellFDD.csfbCsRel2LteSw is “On”.
v.
The highest priority of EUTRAN frequencies is higher than the highest priority of UTRAN frequencies. The frequency and priority acquires from MO_UDePri,
and the detailed strategy and parameters refer to “ZTE UMTS User Dedicated Frequency Priority Feature Guide”. 3.
CS Service Establishment Failure
After the UE is handed over from EUTRAN to UTRAN due to CSFB, if the IU Release Command message of CS domain is received, and if the following conditions are satisfied, the EUTRAN cell downlink central frequency information is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN.
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PS services exist
-
i.
The UE supporting EUTRAN neighboring cells exist.
i.
URncFunction.fastRetEUtranSwch is “On”.
ii.
UCelInfoFDD.csfbMulSrv2LteSw
is
“Handover
Judgment
Based
on
Measurement”. The UE neither supports the PS handover from UMTS to EUTRAN nor the EUTRAN measurement, but only supports EUTRAN (Support
of
E-UTRA
FDD/TDD).
Alternatively,
UCelInfoFDD.csfbMulSrv2LteSw is “Redirection without Measurement”, the UE supports EUTRAN (Support of E-UTRA FDD/TDD). iii.
The highest priority of EUTRAN frequencies is higher than the highest priority of UTRAN frequencies. The frequency and priority acquires from MO_UDePri,
and the detailed strategy and parameters refer to “ZTE UMTS User Dedicated Frequency Priority Feature Guide”. PS services do not exist
-
ii.
The UE supporting EUTRAN neighboring cells exist.
i.
The UE supports the EUTRAN (Support of E-UTRA FDD/TDD).
ii.
URncFunction.fastRetEUtranSwch is “On”.
iii.
UtranCellFDD.csfbCsRel2LteSw is “On”.
iv.
The highest priority of EUTRAN frequencies is higher than the highest priority of UTRAN frequencies. The frequency and priority acquires from MO_UDePri,
and the detailed strategy and parameters refer to “ZTE UMTS User Dedicated Frequency Priority Feature Guide”.
SRVCC
1.
The process of the PS Service when the CS service is released for Multi-RAB Service
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After the UE is handed over from EUTRAN to UTRAN due to SRVCC, if the CS service is released for Multi-RAB, and if the following conditions are satisfied, the EUTRAN cell downlink central frequency information is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN. i.
The UE supporting EUTRAN neighboring cells exist.
ii.
URncFunction.fastRetEUtranSwch is “On”.
iii.
UCelInfoFDD.srvccMulSrv2LteSw
is
“Handover
judgment
Based
on
Measurement”, and the UE neither supports PS handovers to EUTRAN nor the EUTRAN measurement, and the UE only supports EUTRAN (Support of E-UTRA FDD/TDD). OR UCelInfoFDD.srvccMulSrv2LteSw is “Redirection without Measur ement”, and the UE supports EUTRAN (Support of E -UTRA FDD/TDD). iv.
The highest priority of EUTRAN frequencies is higher than the highest priority of UTRAN frequencies. The frequency and priority acquires from MO_UDePri, and the detailed strategy and parameters refer to “ZTE UMTS User Dedicated
Frequency Priority Feature Guide”. 2.
The process of only CS Service After the UE is handed over from EUTRAN to UTRAN due to SRVCC, if the CS service is released for Single-RAB, and if the following conditions are satisfied, the
EUTRAN cell’s downlink central frequency information is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN. i.
The UE supporting EUTRAN neighboring cells exist.
ii.
The UE supports EUTRAN (Support of E-UTRA FDD/TDD).
iii.
URncFunction.fastRetEUtranSwch is “On”.
iv.
UtranCellFDD.srvccCsRel2LteSw is “On”.
v.
The highest priority of EUTRAN frequencies is higher than the highest priority of UTRAN frequencies. The frequency and priority acquires from MO_UDePri,
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and the detailed strategy and parameters refer to “ZTE UMTS User Dedicated Frequency Priority Feature Guide”.
The process of channel switching from CELL_DCH to CELL_FACH If the PS service channel switching from CELL_DCH to CELL_FACH is triggered in UMTS, and if the following conditions are satisfied, the EUTRAN cell downlink central frequency information is filled in the Redirection info of the RRC Connection Release message. Then the UE is redirected to EUTRAN. i.
The UE supporting EUTRAN neighboring cells exist.
ii.
The UE supports EUTRAN (Support of E-UTRA FDD/TDD).
iii.
URncFunction.fastRetEUtranSwch is “On”.
iv.
UCelInfoFDD.dch2FachRetLteSw is “On”.
v.
The highest priority of EUTRAN frequencies is higher than the highest priority of UTRAN frequencies. The frequency and priority acquires from MO_UDePri,
and the detailed strategy and parameters refer to “ZTE UMTS User Dedicated Frequency Priority Feature Guide”. Note: 1.
When the condiftion of fast return to LTE is fulfilled, the RNC acquires UE supporting frequencies from MO_UDePri, then fills 4 FDD and 4 TDD frequencies in RRC Connection Release.
3.1.6
Fast Return Strategy of IUR
Support Fast Return in Redirection Mode via Iur When the SRNC has no radio links and the EUTRAN neighboring cells exist, the SRNC saves the frequency information of EUTRAN neighboring cells returned by the DRNC, and the frequency information of EUTRAN neighboring cells that are the combination of those returned by the DRNC and configured by the SRNC are filled in the Redirection info of the RRC Connection Release message if the redirection conditions are satisfied.
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Currently, only redirection mode is supported.
Support CSFB Indicator via Iur When the SRNC sends the Relocation Request message to the DRNC, if the UE is identified as a CSFB user, the SRNC needs to fill “CSFB” in CSFB Information of the Source to Target Transparent Container to enable the target SRNC to identify the CSFB user and apply the Fast Return to EUTRAN function after the relocation procedure ends.
3.1.7
Special Scenario that CSFB Users are Forbidden to Fast Return to LTE For a CSFB terminated user, after location update, the CS RAB is not assigned but IU connection is released due to CN parameter configuration problem. The UE will return to LTE according to the current strategy, which leads to call failure. Therefore, this function is introduced, fast return to LTE is forbidden in this scenario, to increase the success rate of call setup and improve user experience.
This function is controlled by the parameter URncInfo.csmtIdentifySwch. When URncInfo.csmtIdentifySwch is set to 0, before a CSFB user releasing CS IU connection performs fast return to LTE, the following co nditions need to be judged, if they are both met, fast return to LTE is forbidden, otherwise, fast return to LTE is performed.
3.1.8
CSMT IE is carried in LOCATION UPDATING REQUEST message.
CS RAB has not been established.
Supplementary Services Forbidden to Fast Return to LTE When UE with Supplementary Services performs fast return to LTE during RRC connection release, UE is abnormal during LTE TAU procedure. In this case, this feature is introduced to forbid UE with Supplementary Services fast return to LTE during RRC connection release to improve user experience. This function is controlled by the parameter URncFunction.gresPara56 bit17 When this
parameter is set as “on”, if RNC identifies UE with Supplementary Services through NAS
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and this UE satisfies all criteria of fast return to LTE by redirection mode, then this UE is forbidden to fast return to LTE. Otherwise, this UE is allowed to fast return to LTE .
3.2
ZWF21-03-112 Packet Service Fast Return to LT E for Inactive Mode Whether enabling the dedicated priority functionality affects the judgment on triggering fast return to LTE. See the details in the following chapters.
3.2.1
Strategy without Dedicated Priority When the PS service of the UE in the UTRAN network migrates from other states to URA_PCH/CELL_PCH or IDLE, including CELL_DCH -> CELL_PCH/URA_PCH, CELL_DCH -> IDLE, CELL_FACH -> CELL_PCH/URA_PCH, and CELL_FACH -> IDLE, perform the Redirection flow as long as the following four conditions are met. Fill in the downlink central frequency information in Redirection info of RRC Connection Release. And the UE returns to the EUTRAN network.
3.2.2
1.
There are EUTRAN neighboring cells;
2.
The UE is capable of “Support of E-UTRA FDD/TDD ”;
3.
URncFunction.fastRetEUtranSwch is “on”;
4.
UExtCelInfoFDD.pchIdleRetLteSw is “on”.
Strategy with Dedicated Priority When both ULogicalRnc.dePriRncSwch and UExtCelInfoFDD.dePriSwch are enabled, the processing is described below. When the PS service of the UE in the UTRAN network migrates from other states to URA_PCH/CELL_PCH or IDLE, including CELL_DCH -> CELL_PCH/URA_PCH, CELL_DCH -> IDLE, CELL_FACH -> CELL_PCH/URA_PCH, and CELL_FACH -> IDLE,
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perform the Redirection flow as long as the following four conditions are met. Fill in the downlink central frequency information in Redirection info of RRC Connection Release. And the UE returns to the EUTRAN network. 1.
The UE is capable of “Support of E-UTRA FDD/TDD”;
2.
URncFunction.fastRetEUtranSwch is “on”;
3.
UExtCelInfoFDD.pchIdleRetLteSw is “on”;
4.
The highest priority of EUTRAN frequencies is higher than the highest priority of UTRAN frequencies.
Note: When the UE meets the conditions of fast return to LTE, the RNC acquires UE supporting frequencies from MO_UDePri. Excluding the frequency which the UE does not support, fill in the LTE frequency in the RRC Connection Release message according to the dedicated priority from the highest to the lowest. Fill in at most four frequencies for FDD and TDD respectively.
3.3
ZWF21-03-113 Packet Service Fast Return to LT E for Active Mode For the PS service in CELL_DCH, the RNC actively triggers fast return to LTE to improve
user’s experience. Whether enabling the dedicated priority functionality affects the judgment on triggering fast return to LTE. See the details in the following chapters.
3.3.1
Strategy without Dedicated Priority For the PS service in CELL_DCH, the RNC actively triggers fast return to LTE, which is controlled
by
UExtCelInfoFDD.dchPsBldRedLteSw.
When
URncFunction.fastRetEUtranSwch is “on”,
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When establishing the PS service, if UExtCelInfoFDD.dchPsBldRedLteSw is enabled and the UE supports LTE, start the timer PSOnUMTSTimer.
If the “penalty on UE” flag is “false”, the timer PSOnUMTSTimer is taken from the best cell’s parameter UExtCelInfoFDD.bldRedLteT1Short ;
If the “penalty on UE” flag is “true”, the timer PSOnUMTSTimer is taken from the best cell’s parameter UExtCelInfoFDD.bldRedLteT1Long ;
For description of “penalty on UE” flag, please refer to chapter 3.4.
When the timer PSOnUMTSTimer is up, the “penalty on UE” flag is set to be “false”. If the following conditions are met, release the RRC connection and make the UE fast return to LTE. 1.
The parameter UExtCelInfoFDD.dchPsBldRedLteSw of the best cell is “ on”;
2.
In CELL_DCH mode, only PS service through Iu interface is available;
3.
There are EUTRAN neighboring cells.
Otherwise, restart PSOnUMTSTimer. Note: 1.
Keep the timer if the best cell has changed before the timer is up;
2.
When the UE moves across the RNC, take the parameters of the cell to which the last link on SRNC belongs as long as there are no links on SRNC;
3.
When the UE meets the conditions of fast return to LTE, find the EUTRAN frequencies of which the UE is capable from the existing EUTRAN neighboring cells. In the Redirection of the RRC Connection Release message, fill in at most four EUTRAN FDD frequencies and four EUTRAN TDD frequencies.
3.3.2
Strategy with Dedicated Priority When both ULogicalRnc.dePriRncSwch and UExtCelInfoFDD.dePriSwch are enabled, and URncFunction.fastRetEUtranSwch is “on”, the processing is described below.
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For the PS service in CELL_DCH, the RNC actively triggers fast return to LTE, which is controlled by UExtCelInfoFDD.dchPsBldRedLteSw. When establishing the PS service, if UExtCelInfoFDD.dchPsBldRedLteSw is enabled and the UE supports LTE, start the timer PSOnUMTSTimer.
If the “penalty on UE” flag is “false”, the timer PSOnUMTSTimer is taken from the
best cell’s parameter UExtCelInfoFDD.bldRedLteT1Short ; If the “penalty on UE” flag is “true”, the timer PSOnUMTSTimer is taken from the
best cell’s parameter UExtCelInfoFDD.bldRedLteT1Long ; For description of “penalty on UE” flag, please refer to chapter 3.4.
When the timer PSOnUMTSTimer is up, the “penalty on UE” flag is set to be “false”. If the following conditions are met, release the RRC connection and make the UE fast return to LTE. 1.
The parameter UExtCelInfoFDD.dchPsBldRedLteSw of the best cell is “ on”;
2.
In CELL_DCH mode, only PS service through Iu interface is available;
3.
There are EUTRAN neighboring cells;
4.
The highest priority of EUTRAN frequencies higher than the highest priority among UTRAN frequencies.
Otherwise, restart PSOnUMTSTimer. Note: 1.
Keep the timer if the best cell has changed before the timer is up;
2.
When the UE moves across the RNC, take the parameters of the cell to which the last link on SRNC belongs as long as there are no links on SRNC;
3.
When the UE meets the conditions of fast return to LTE, the RNC acquires UE supporting frequencies from MO_UDePri. Excluding the frequency points which the UE does not support, fill in the LTE frequencies in the RRC Connection Release message according to the dedicated priority from the highest to the lowest. Fill in at most four frequencies for FDD and TDD respectively.
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3.4
Penalty strategy
3.4.1
Penalty Mechanism Principle To avoid UE’s ping-pong redirection between UTRAN and LTE in the LTE poorly covered districts, the penalty mechanism is applied. That is, when RNC initiates the fast return to LTE, the timer blindRedLteT2 is enabled. Before it expires, if RNC receives UE’s RRC connection request again, the LTE is considered to fail to provide the service to the UE, then the UE is punished. During the penalty period (PSOnUMTSTimer), RNC does not perform the Fast Return to LTE for the UE. The feature is controlled by UExtCelInfoFDD.blindRedPenSw . The following scenarios suit the Fast Return to LTE without measurement redirection.
PS Service when the CS service is released for Multi-RAB Service (including CS service establishment failure)
Fast return to LTE in data service inactivated mode
Fast return to LTE in data service activated mode
1.
For “Fast return to LTE in data service activated mode”, please refer to chapter 3.3;
2.
Following lists how to handle other scenarios. -
When establishing PS service, if UExtCelInfoFDD.dchPsBldRedLteSw is enabled and the UE supports LTE, and the “penalty on UE” flag is “True”, activate the timer PSOnUMTSTimer. The PSOnUMTSTimer is obtained from
the best service cell’s parameter UExtCelInfoFDD.bldRedLteT1Long. During the penalty period, if the above scenario satisfies the conditions of UE fast return to LTE and the “penalty on UE” flag is “True”, no fast return to LTE is performed. -
When PSOnUMTSTimer expires, set the “penalty on UE” flag to “False”. Restart the PSOnUMTSTimer, whose value is obtained from the best service
cell’s parameter UExtCelInfoFDD.bldRedLteT1Short..
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3.4.2
Penalty on UE Flag The “penalty on UE” flag indicates the UE that initiates RRC connection request again after original Fast Return to LTE. The default value is False. In the above mentioned scenario, when the RNC executes RRC connection release and Fast Return to LTE, enable the timer UExtCelInfoFDD.blindRedLteT2..
If the UE’s timer does not expire, -
Terminate the timer after receiving UE’s non -CSFB RRC connection request, and set the “penalty on UE” flag to True.
-
Terminate the timer after receiving UE’s CSFB RRC connection request, and set the “penalty on UE” flag to False.
If the UE’s timer expires, -
Set the punished UE flag to “False” if not receiving UE’s RRC connection request.
3.5
EUTRAN Frequency Priority If the EUTRAN network has multiple frequencies, when UE is handed over or redirected from UTRAN to EUTRAN, RNC hands over or redirects UE to the preset highest priority EUTRAN frequency. The feature is controlled by UExtCelInfoFDD.prioBsdHoRedi4ESw.
3.5.1
Frequency Priority Configuration Configure the frequency priority according to the following parameters.
EUTRAN
neighboring
cell’s
frequency
number
is
indicated
by
UUtranCellFDD.eutraFreqNum. EUTRAN frequency is indicated by dlEARFCN
is
the
number
UUtranCellFDD.dlEARFCN. Among group,
dimension
is
indicated
which, by
UUtranCellFDD.eutraFreqNum.
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EUTRAN frequency priority is indicated by UUtranCellFDD.frePrio4EHoRedi. Note: EUTRAN frequency requires frequency configured by EUTRAN neighboring cell configuration (MO UEUtranRelation) to perform configuration.
3.5.2
Frequency Priority Strategy in Handover/Redirection During the handover/redirection from UMTS to EUTRAN, the following strategies can be achieved according to the configured frequency priorities.
Measurement based handover/redirection i.
After receiving the measurement report, sequence the cells by the frequency priority.
ii.
If performing handover, select the cell at the highest frequency priority to initiate the handover.
iii.
If the redirection is executed, fill in the frequency at the highest priority level in Inter-RAT info of Release Info under RRC Connection Release. If several frequency priority levels are the same, fill in all of them. FDD and TDD can be filled in up to 4 respectively.
Redirection without measurement i.
For the EUTRAN neighboring cell frequency list maintained in the network side, sequence them by the frequency priority order.
ii.
If the RRC Connection Reject redirection is executed, fill in the Inter-RAT info by the frequency priority levels from high to low of Redirection Info. FDD and TDD can be filled in up to 4 respectively.
iii.
If the RRC Connection Reject redirection is executed, fill in the frequency at the highest priority level in Inter-RAT info of Redirection Info. If several frequency priority levels are the same, fill in all of them. FDD and TDD can be filled in up to 4 respectively.
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Note: 1.
1 For executing handover or redirection decision, see ZTE UMTS Handover with LTE Feature Guide.
2.
For executing RRC Connection Reject or RRC Connection Release redirection decision, see ZTE UMTS RRC Connection Redirect Feature Guide .
3.5.3
Relationship with Dedicated Priority For RRC connection redirection triggered by the congestion or load control and the Fast return to LTE based redirection scenarios, if the dedicated priority is enabled and the corresponding priority information is configured, this feature is not executed. Among which, 1.
For the RRC connection redirection triggered by the forced release of services that congestion and load control trigger, see ZTE UMTS RRC Connection Redirect Feature Guide.
2.
For the Fast return to LTE based redirection, see ZTE UMTS Fast Return to LTE Feature Guide.
3.
For the dedicated priority configuration, see ZTE UMTS User Dedicated Frequency Priority Feature Guide.
3.6
Optimization of Redirection to LTE Strategy for Only PS Signaling For a UE forbidden to access the LTE due to EUTRAN service handover attribute, the UE can be redirected to LTE when it has onl y PS signaling, and the access failure in LT E occurs. To avoid this kind of failure, the RNC should determine the EUTRAN service handover attribute of PS services which the UE had established. When the redirection to LTE is triggered to a UE which has only PS signaling and no PS services,
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If the EUTRAN service handover attribute (“Handover to E-UTRAN shall not be performed”) is carried by one of PS services which the UE had established, the UE with only PS signaling is not permitted to redirect to LTE.
If the EUTRAN service handover attribute is not carried by any of PS services which the UE had established, or no PS services had been established, the UE with only PS signaling is permitted to redirect to LTE.
4
Parameters
4.1
ZWF21-03-111 Fast Return to LTE Managed
Logic
Object
Name
Parameter Description
Value Range
Unit
Default Value
Recom mende d Value
This parameter is a global switch that enables or disables fast return of UE to the EUTRAN. When this switch is turned on, the RNC in a network with both UMTS and EUTRAN deployed can instruct a UE to fast return URncFunc tion.fastR etEUtranS wch
RNC
to the EUTRAN upon a CS
Switch of
release after the UE is handed
Fast Return over from the EUTRAN to the to
UTRAN due to CSFB or
E-UTRAN
SRVCC.
0:Off 1:On
BYTE
0:Off
1:On
When this switch is turned off, the RNC in a network with both UMTS and EUTRAN deployed will not instruct a UE to fast return to the EUTRAN upon a CS release after the UE is handed over from the EUTRAN to the UTRAN due to CSFB or
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Managed
Logic
Object
Name
Value
Parameter Description
Unit
Range
Default Value
Recom mende d Value
SRVCC. 0: Off 1:
The parameter indicates Switch of PS Service Fast Return UCelInfoF to EUTRAN DD.csfbM when CS is ulSrv2Lte released for Sw
EUTRAN CSFB Multi-RAB Service
Handov
whether EUTRAN measurement and compressed mode are initialized to hand over the PS service to EUTRAN as soon as possible or redirect it to EUTRAN without measurement after the CS service is released for multi-RAB with CSFB from
er udgme nt
2:
Based
Redirec
on Measur
N/A
0: Off
tion without
ement
Measur
2:
ement
Redirect
EUTRAN, so that better EUTRAN services are provided for UEs that support EUTRAN.
ion without Measur ement
PS Handover Mode when URncInfo. CS is csfbPsHo released for 2LteMode EUTRAN CSFB Multi-RAB
This parameter indicates the
0: PS
mode of PS handover from
Handov
UTRAN to EUTRAN. PS
er
handover or redirection can be 1: adopted based on UE
Redirect
capability.
ion
0: PS N/A
1:
Handov Redirec er
tion
s
10
10
N/A
Off
1: On
Service when pre-redirection information is not indicated in URncInfo.
Timer for
RRC connection Request,
if
CSFB the time between RRC csfbIdentif Identificatio connection Request and CS yTimer n RAB establish is not greater
0..6553 5
than the parameter, the service is indicated CSFB. UtranCell Switch of
This parameter indicates cell
FDD.csfb Fast Return switch of fast return to CsRel2Lte to EUTRAN EUTRAN for CS service. If the
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0: Off 1: On
37
Fast Return to LTE
Managed
Logic
Object
Name
Sw
Parameter Description
when
switch is On, when CS is
EUTRAN
released, frequency of
Value
Unit
Range
Default Value
Recom mende d Value
CSFB CS is EUTRAN is filled in redirection released
IE. This parameter indicates the number of users with
UCelInfoF
User
compressed mode activated
Number
for the balance strategy based
with
on measurement. When a new
Compresse user accesses and
d Mode DD.simCo Activation mpUserN for Balance um Strategy Based On
measurement balance requirements are satisfied, if the number of current users in
0..255, step 1
N/A
16
16
s
6
6
N/A
0: Off
1: On
compressed mode is not less than this parameter,
Measureme compressed mode will not be nt
activated, compressed mode will be activated after rab assignment procedure. This parameter indicates timer of deactivate compressed mode for Fast Return to
Timer of URncInfo. psHoLteM easTimer
EUTRAN.If compressed mode
Deactivate is initialized due to fast return Compresse to EUTRAN, the timer
(1..255)
d Mode for activates. When the timer
s, step
Fast Return expired, if event (3C) doesn’ t 1s to EUTRAN report, RNC will judge whether compressed mode is deactivate or not based on c urrent signal quality. Switch of
When single ps service is
UCelInfoF Fast Return transfer from CELL_DCH to DD.dch2F to EUTRAN CELL_FACH, the parameter
0: Off
achRetLte for PS Only indicates whether fast return to 1: On Sw
when UE
EUTRAN will be performed. If
RRC Status the parameter is On,
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RNC will
38
Fast Return to LTE
Managed
Logic
Object
Name
Parameter Description
Value Range
Unit
Default Value
Recom mende d Value
Transferrin initial RRC connection release g from
and fill EUTRAN cells'
CELL_DCH frequency. to CELL_FAC H This parameter is the switch of checking the UE E-UTRA Switch of URncInfo . checking cheEutraC the UE apiSw
E-UTRA Capability
Capability before initiating the PS handover procedure from UMTS to LTE. The parameter 0: Off is On, check that whether UE
1: On
N/A
0: Off
1: On
reports the UE E-UTRA Capability, if reports, the PS handover procedure is permitted, else not. The parameter indicates
ULogicalR RNC nc.rncSrvc SRVCC cSw
Switch
whether RNC supports the SRVCC function of
0: Off
TE->UTRAN to provide
1: On
N/A
0: Off
1: On
continuity of voice services between LTE and UTRAN. 0: Off
Switch of PS Service Fast Return UCelInfoF to EUTRAN DD.srvcc when CS is MulSrv2Lt released for eSw
EUTRAN SRVCC Multi-RAB Service
The parameter indicates
1:
whether EUTRAN
Handov
measurement and compressed er mode are initialized to hand
udgme
over the PS service to
nt
EUTRAN as soon as possible Based or redirect it to EUTRAN
on
N/A
0: Off
0: Off
without measurement after the Measur CS service is released for
ement
multi-RAB with SRVCC from
2:
EUTRAN, so that better
Redirect
EUTRAN services are provided ion for UEs that support EUTRAN. without Measur
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39
Fast Return to LTE
Managed
Logic
Object
Name
Value
Parameter Description
Range
Unit
Default Value
Recom mende d Value
ement PS Handover URncInfo. srvccPsH o2LteMod e
Mode when CS is released for EUTRAN SRVCC Multi-RAB
This parameter indicates the
0: PS
mode of PS handover from
Handov
UTRAN to EUTRAN. PS
er
handover or redirection can be 1: adopted based on UE
Redirect
capability.
ion
0: PS N/A
0: PS
Handov Handov er
er
N/A
0: Off
0: Off
N/A
0: Off
0: Off
N/A
0: Off
0: Off
Service Switch of UtranCell FDD.srvcc CsRel2Lte Sw
This parameter indicates cell
Fast Return switch of fast return to to EUTRAN EUTRAN for CS service.If the when
switch is On, when CS is
EUTRAN
released, frequency of
0: Off 1: On
SRVCC CS EUTRAN is filled in redirection is released IE. This parameter indicates whether a CSFB user is forbidden to fast return to LTE. When this parameter is set to 1, a CSFB user is not forbidden to fast return to LTE. When this
URncInfo. csmtIdenti fySwch
CSMT IE
parameter is set to 0, if a CSFB
for CSFB
user is a called user which
0: Off
Identificatio having the location updating n Switch
1: On
(CSMT IE is carried in LOCATION UPDATING REQUEST message), and have not established any CS RAB, this user is forbidden to fast return to LTE, otherwise, not forbidden.
URncInfo. ueLteCap JugSw
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UE LTE
This
parameter
Capability
disables
UE
Judgement determination Switch
enables
or
capability 0: Off when
the 1: On
capability of the UE is not
40
Fast Return to LTE
Managed
Logic
Object
Name
Value
Parameter Description
Unit
Range
Default Value
Recom mende d Value
obtained. 0: The UE does not support the LTE capability. 1: If the "CSFB Information" IE is contained in a Relocation Request capability
message, of
considered
the
as
the UE
is
"Support
of
E-UTRA FDD/TDD". The parameter is the switch of UExtCelIn Dedicated foFDD.de priority PriSwch
Switch
dedicated priority. When this function is on, it could make 0: Off expected UE camp on some 1: On
N/A
0: Off
0: Off
N/A
0:off
0:off
N/A
0: Off
1: On
10
10
frequency when UEs leave CELL_DCH.
The
it could make
parameter camp
expected UE
on some frequency
is the RNC when UEs leave CELL_DCH. ULogicalR switch of
0:off
nc.dePriR dedicated ncSwch
1:on
priority. When this function is on This parameter is Blind Fast
UExtCelIn Blind Fast
Return to LTE penalty Switch.
foFDD.blin Return to
When this parameter is on, 0: Off
dRedPen LTE penalty there is a penalty mechanism 1: On Sw
Switch
for PS Blind Fast Return to LTE. This
parameter
is
Blind
redirection to LTE Timer 2. UExtCelIn Blind
when UE is Blind Fast Return
foFDD.blin redirection to LTE, this timer starts. If RNC dRedLteT to LTE
recerives
2
connection request before this
Timer 2
a
UE's
RRC
(1..1800 )s, step s 1s
timer expires, LTE coverage would be considered to be bad
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41
Fast Return to LTE
Managed
Logic
Object
Name
Parameter Description
Value Range
Unit
Default Value
Recom mende d Value
and not to provide service for this
UE;
otherwise,
LTE
coverage would be consedered to be good. bit17:
Switch
of
Forbid
Supplementary Services fast return
to
lte
during
RRC
connection release URncFunc tion.gresP ara56
Global Reserved Parameter 56
If this parameter is set as "1:On":
Supplementary
Services cannot fast return to lte
during
RRC
connection
0: Off 1: On
N/A
0: Off
1: On
release If this parameter is set as "0:off":
Supplementary
Services can fast return to lte during RRC connection release
4.2
ZWF21-03-112 Packet Service Fast Return to LT E for Inactive Mode Managed
Logic
Object
Name Switch of Fast Return to EUTRAN for PS
UExtCelIn when UE foFDD.pc RRC Status hIdleRetLt Transferrin eSw
g to PCH/IDLE (CELL_PC H/URA_PC H/idle)
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Parameter Description
Value Range
Unit
Default Value
Recom mende d Value
This parameter indicates whether fast return to EUTRAN is performed when a PS service is transferred to PCH/IDLE (CELL_PCH/URA_PCH/idle). If this parameter is set to On, the
0:Off 1:On
BYTE
0:Off
1:On
RNC initiates RRC connection release and fills EUTRAN frequency information in the redirection field.
42
Fast Return to LTE
4.3
ZWF21-03-113 Packet Service Fast Return to LT E for Active Mode Managed
Logic
Object
Name
UExtCelIn foFDD.dc hPsBldRe dLteSw
PS in CELL_DCH Blind Fast Return to LTE Switch
Parameter Description
Value
Unit
Range
Default Value
Recom mende d Value
This parameter is PS in CELL_DCH Blind Fast Return to LTE Switch. When PS stays 0:Off in CELL_DCH, RNC will trigger 1:On
BYTE
0:Off
1:On
s
10
10
s
600
600
UE fast returns to LTE, without measurement. This parameter is Blind redirection to LTE Timer 1 Short. Regards to PS in
UExtCelIn foFDD.bld RedLteT1 Short
Blind redirection to LTE Timer 1 (Short)
CELL_DCH Blind Fast Return to LTE, if RNC does not
(1..6553
recerive a UE's RRC
5)s,
connection request before
step 1s
blindRedLteT2 expires, LTE coverage would be considered good, and set a short timer(bldRedLteT1Short) for UE. This parameter is Blind redirection to LTE Timer 1 Long. Afer UE Blind Fast Returns to LTE, if RNC
UExtCelIn foFDD.bld RedLteT1 Long
Blind redirection to LTE Timer 1 (Long)
recerives a UE's RRC connection request before
(1..6553
blindRedLteT2 expires, LTE
5)s,
coverage would be considered step 1s bad and not to provide service for UE, and a long timer(bldRedLteT1Long) is set for UE. UE could not fast return to LTE before bldRedLteT1Long expires.
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43
Fast Return to LTE
4.4
EUTRAN Frequency Priority Managed
Logic
Parameter
Object
Name
Description
Value Range
Unit
Default Value
Recom mende d Value
This parameter indicates whether to consider the frequency priority of neighbor cells in Switch of Considering Frequency UExtCelIn Priority in foFDD.pri UMTS->EoBsdHoR UTRAN edi4ESw Inter-RAT Handover or Redirection
E-UTRAN inter-RAT handover or redirection. The parameter is "On", the neighbor cell with the highest frequency priority is taken as the
0:Off 1:On
BYTE
0:Off
1:On
N/A
-
-
-
-
target cell for handover or redirection. The parameter is "Off", the frequency priority is not considered in E-UTRAN inter-RAT handover or redirection. This parameter indicates the number
Number of of neighbor EUTRAN UUtranCel EUTRAN
centre frequencies.
lFDD.eutr Centre
The number of
0..16
aFreqNum Frequencie frequencies and its s
priorities are configured according to this parameter.
Downlink
The parameter
Band 1: 0-599,
UUtranCel E-UTRAN
indicates the downlink Band 2:
lFDD.dlEA Absolute
E-UTRAN Absolute
600-1199, Band N/A
RFCN
Radio Frequency
3: 1200-1949,
Radio
Frequency Channel Number
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Band 4:
44
Fast Return to LTE
Managed
Logic
Parameter
Object
Name
Description
Channel
(EARFCN).
Number for dlEARFCN and Indicating
Unit
Value
Recom mende d Value
1950-2399, Band 5: 2400-2649,
frePrio4EHoRedi are Band 6:
Frequency used in pairs, and Priority
Value Range
Default
2650-2749, Band
there is a one-to-one 7: 2750-3449, correspondence
Band 8:
between each
3450-3799, Band
frequency in
9: 3800-4149,
dlEARFCN and its
Band 10:
priority in
4150-4749, Band
frePrio4EHoRedi.
11: 4750-4949, Band 12:
F_DL = F_DL_low +
5010-5179, Band
0.1 * (N_DL –
13: 5180-5279,
N_Offs-Dl), where
Band 14:
F_DL is center carrier 5280-5379, Band frequency, F_DL_low 17: 5730-5849, is dl lowest carrier
Band 18:
frequency, N_DL is
5850-5999, Band
DlEARFCN,
19: 6000-6149,
N_Offs-Dl is carrier
Band 20:
frequency offset
6150-6449, Band
indicated by band
21: 6450-6599,
indicator.
Band 22:
DBS_FP_MAX_NUM 6600-7399, Band _EUTRAN_FREQ is 23: 7500-7699, the maximum number Band 24: of neighbor EUTRAN 7700-8039, Band centre frequencies,
25: 8040-8689,
the value is 16.
Band 26: 8690-9039, Band 27: 9040-9209, Band 28: 9210-9659, Band 29: 9660-9769, Band 33: 36000-36199, Band 34:
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Fast Return to LTE
Managed
Logic
Parameter
Object
Name
Description
Value Range
Unit
Default Value
Recom mende d Value
36200-36349, Band 35: 36350-36949, Band 36: 36950-37549, Band 37: 37550-37749, Band 38: 37750-38249, Band 39: 38250-38649, Band 40: 38650-39649, Band 41: 39650-41589, Band 42: 41590-43589, Band 43: 43590-45589, Band 44: 45590-46589 This parameter indicates the frequency priority of neighbor cells in E-UTRAN inter-RAT Frequency handover or UUtranCel
Priority for redirection.The lowest
E-UTRAN lFDD.frePr Inter-RAT io4EHoRe Handover di or
priority is 0, and the highest priority is 2.
(0..2)
N/A
-
-
dlEARFCN and frePrio4EHoRedi are
Redirection used in pairs, and there is a one-to-one correspondence between each frequency in dlEARFCN and its
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46
Fast Return to LTE
Managed
Logic
Parameter
Object
Name
Description
Value Range
Unit
Default Value
Recom mende d Value
priority in frePrio4EHoRedi. DBS_FP_MAX_NUM _EUTRAN_FREQ is the maximum number of neighbor EUTRAN centre frequencies, the value is 16.
5
Related Counters and Alarms
5.1
Related Counters
5.1.1
ZWF21-03-111 Fast Return to LTE
Table 5-1
Counter List
Counter ID 312106776
314087002
5.1.2
Name Number of attempted relocation preparation for outgoing PS inter-RAT handovers(Utran to EUtran) Number of RRC connection release for redirection to LTE,cause by fast return
ZWF21-03-112 Packet Service Fast Return to LTE for Inactive Mode
Table 5-2
Counter List
Counter ID 312106776
314087002
ZTE Confidential Proprietary
Name
Number of attempted relocation preparation for outgoing PS inter-RAT handovers(Utran to EUtran) Number of RRC connection release for redirection to LTE,cause by fast return
47
Fast Return to LTE
5.1.3
ZWF21-03-113 Packet Service Fast Return to LTE for Active Mode
Table 5-3
Counter List
Counter ID 312106776
314087002
5.2
Name Number of attempted relocation preparation for outgoing PS inter-RAT handovers(Utran to EUtran) Number of RRC connection release for redirection to LTE,cause by fast return
Related Alarms This feature has no related alarm.
6
Engineering Guide
6.1
Application Scenario This feature is applied to the UTRAN and EUTRAN association scenario. Different sub-functions are suit for different scenes. When the UMTS and EUTRAN are jointly deployed, the UE in EUTRAN is handed over to UTRAN owing to CSFB, SRVCC. To make these UEs get better service experience, the UTRAN side will return them to EUTRAN by mode of PS HO or Redirection. 1.
When the function of IMS is not supported in LTE, the fast return to LTE for the CSFB service can be applied to all the scenes to guarantee the voice call establishment successfully.
2.
For the SRVCC service, because the triggering conditions from LTE to UMTS are based on the signaling quality or load congestion in general, this function is always set to off to avoid the ping-pong reselection/handover between UMTS and LTE.
3.
For the PS service from CELL_DCH to CELL_FACH or CELL_DCH/CELL_FACH to URA_PCH/CELL_PCH/IDLE,
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The
Ping-Pong
reselection/handover
may
be
48
Fast Return to LTE
happened without LTE quality judgment. The function should be avoided to be activated in the area which is poor coverage by LTE, otherwise the KPI and service performance will be influenced. 4.
For priority function, the RNC handovers or redirects the users to specific frequency, so as to control load distribute in multi frequency layers scene
5.
For the PS service in CELL_FACH, the RNC triggers fast return to LTE based on
the UEs’ measurement report as soon as possible, so as to control load distribute in multi- frequency scene. 6.
For the PS service in CELL_DCH, the RNC actively triggers fast return to LTE to improve users experience.
6.2
Feature Activation Procedure
6.2.1
Fast Return to LTE The purpose of this chapter is just to guide the reader how to find the GUI location of the parameters which are related to the deployment of this feature. The values indicated by the captures possibly are not the real value to configure. Please refer to the last column of table in chapter 4.1 for the practical configuration value. In the configuration resource tree window, open the [Modify Area->Managed Element->
UMTS Logical Function Configuration] interface and set the parameter “ RNC Switch of Fast Return to E-UTRAN ”, as shown in Figure 6-1
Figure 6-1
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Parameters configuration interface 1
49
Fast Return to LTE
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration->UTRAN Cell->Extended Info of UTRAN Cell]
interface and set the parameter “Switch of PS Service Fast Return to EUTRAN when CS is released for EUTRAN CSFB Multi- RAB Service”, as shown in Figure 6-2.
Figure 6-2
Parameters configuration interface 2
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration->Extended Info of RNC] interface and set the
parameter “PS Handover Mode when CS is released for EUTRAN CSFB Multi-RAB Service”, “Timer of Deactivate Compressed Mode for Fast Return to EUTRAN”, “Timer
for CSFB Identification(s)”, as shown in Figure 6-3 Figure 6-3
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Parameters configuration interface 3
50
Fast Return to LTE
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration->UTRAN Cell] interface and set the parameter
“Switch of Fast Return to EUTRAN when EUTRAN CSFB CS is released”, as shown in Figure 6-4
Figure 6-4
Parameters configuration interface 4
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration->UTRAN Cell->Extended Info of UTRAN Cell]
interface and set the parameter “User Number with Compressed Mode Activation for Balance Strategy Based On Measurement”,as shown in Figure 6-5.
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51
Fast Return to LTE
Figure 6-5
Parameters configuration interface 5
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration->UTRAN Cell->Extended Info of UTRAN Cell]
interface and set the parameter “ Switch of Fast Return to EUTRAN for PS Only when UE RRC Status Transferring from CELL_DCH to CELL_FACH ”, as shown in Figure 6-6
Figure 6-6
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Parameters configuration interface 6
52
Fast Return to LTE
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration->Extended Info of RNC] interface and set the
parameter “Switch of checking the UE E -UTRA Capability”,as shown in Figure 6-7 Figure 6-7
Parameters configuration interface 7
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration->PLMN Relating Configuration->Logic RNC Configuration] interface and set the parameter “RNC SRVCC Switch”, as shown in Figure 6-8
Figure 6-8
Parameters configuration interface 8
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration->UTRAN Cell->Extended Info of UTRAN Cell]
interface and set the parameter “Switch of PS Service Fast Return to EUTRAN when CS is released for EUTRAN SRVCC Multi- RAB Service”, as shown in Figure 6-9.
ZTE Confidential Proprietary
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Fast Return to LTE
Figure 6-9
Parameters configuration interface 9
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration->Extended Info of RNC] interface and set the
parameter “PS Handover Mode when CS is released for EUTRAN SRVCC Multi-RAB Service”,as shown in Figure 6-10
Figure 6-10
Parameters configuration interface 10
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration-> UTRAN Cell] interface and set the parameter
“Switch of Fast Return to EUT RAN when EUTRAN SRVCC CS is released ”, as shown in Figure 6-11
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Fast Return to LTE
Figure 6-11
Parameters configuration interface 11
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration-> PLMN Relating Configuration-> Logic RNC Configuration] interface and set the parameter “Dedicated priority RNC Switch ”, as shown in Figure 6-12
Figure 6-12
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Parameters configuration interface 12
55
Fast Return to LTE
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration-> UTRAN Cell->Extended Information 2 of UT RAN Cell] interface and set the parameter “Dedicated priority Switch ”, as shown in Figure 6-13
Figure 6-13
Parameters configuration interface 13
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration->Extended info of RNC] interface and set the
parameter “Switch of acquiring SPID based on IMEI ”, as shown in Figure 6-14.
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Fast Return to LTE
Figure 6-14
Parameters configuration interface 14
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration->Global Information Configuration->SPID and PriGroup relationship Profile->SPID and PriGroup relationship] interface and set the
parameter “SPID Index”,as shown in Figure 6-15 Figure 6-15
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Parameters configuration interface 15
57
Fast Return to LTE
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration->Service Configuration->RAN Priority When UE in Dedicated State ] interface and set the parameter “ Priority Group ID ”, as shown in Figure 6-16
Figure 6-16
Parameters configuration interface 16
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration->Service Configuration->Imei TAC List for SPID]
interface and set the parameter “SPID configured by RNC ”, “Length of IMEI TAC”,”Imei TAC”, as shown in Figure 6-17
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Fast Return to LTE
Figure 6-17
6.2.2
Parameters configuration interface 17
Packet Service Fast Return to LTE for Inactive Mode
The purpose of this chapter is just to guide the reader how to find the GUI location of the parameters which are related to the deployment of this feature. The values indicated by the captures possibly are not the real value to configure. Please refer to the last column of table in chapter 4.2 for the practical configuration value. In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration-> UTRAN Cell-> Extended Information 2 of
UTRAN Cell] interface and set the parameter “ Switch of Fast Return to EUTRAN for PS when UE RRC Status Transferring to PCH/IDLE(CELL_PCH/URA_PCH/idle)” , as shown in Figure 6-18
ZTE Confidential Proprietary
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Fast Return to LTE
Figure 6-18
6.2.3
Parameters configuration interface 18
Packet Service Fast Return to LTE for Active Mode The purpose of this chapter is just to guide the reader how to find the GUI location of the parameters which are related to the deployment of this feature. The values indicated by the captures possibly are not the real value to configure. Please refer to the last column of table in chapter 4.3 for the practical configuration value. In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration-> UTRAN Cell-> Extended Information 2 of
UTRAN Cell] interface and set the parameter “ PS in CELL-DCH Blind Fast Return to LTE Switch”,”Blind redirection to LTE Timer 1(Short)” , ”Blind redirection to LTE Timer
1(Long)”, as shown in Figure 6-19
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Fast Return to LTE
Figure 6-19
6.2.4
Parameters configuration interface 19
EUTRAN Frequency Priority In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration-> UTRAN Cell-> Extended Information 2 of
UTRAN Cell] interface and set the parameter “ Switch of Considering Frequency Priority in UMTS->E-UTRAN Inter- RAT Handover or Redirection”, as shown in as shown in Figure 6-20
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Fast Return to LTE
Figure 6-20
Parameters configuration interface 20
In the configuration resource tree window, open the [Modify Area->Managed Element-> UMTS Logical Function Configuration-> UTRAN Cell] interface and set the parameter
“Number of EUTRAN Centre Frequencies ”,” Downlink E-UTRAN Absolute Radio Frequency Channel Number for Indicating Frequency Priority ”, ” Frequency Priority for E-UTRAN Inter-RAT Handover or Redirection ”, as shown in Figure 6-21
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Fast Return to LTE
Figure 6-21
Parameters configuration interface 21
6.3
Feature Validation Procedure
6.3.1
Fast Return to LTE for CSFB
Table 6-1
Feature Validation Procedure 1
Test Item
Fast Return to LTE 1.
WCDMA and LTE system is ready.
2.
Cell1 supports HSUPA, HSDPA and DCH, Cell1 belongs to RNC1/NodeB1. Cell2 belongs to eNodeB1.
3.
Configure Cell1 with Cell2 adjacent cells with different
Preconditions coverage. 4.
Configure RNC support Fast Return to LTE function
5.
UE1 with R8 or higher versions supports both of UMTS and LTE and camps on EUTRAN Cell2 in Idle mode.
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Fast Return to LTE
Test Item
Fast Return to LTE 1.
UE1 makes a CS call to PSTN in EUTRAN cell2.
2.
ENodeB triggers the CSFB service from the Cell2 to Cell1, the
Test Steps CS service establishes on UTRAN Cell1.
Anticipative
3.
Release the CS call and then UE1 fast return to LTE.
1.
In step3, UE1 performs the fast return to EUTRAN Cell2
Result
6.3.2
successfully.
Pack Service Fast Return to LTE for Inactive Mode
Table 6-2
Feature Validation Procedure 2
Test Item
Fast Return to LTE 1.
WCDMA and LTE system is ready.
2.
Cell1 supports HSUPA, HSDPA and DCH, Cell1 belongs to RNC1/NodeB1. Cell2 belongs to eNodeB1.
3. Preconditions
Configure Cell1 and Cell2 as adjacent cells with different coverage.
4.
Configure RNC support Fast Return to LTE function for inactive mode..
5.
UE1 with R8 or higher versions supports both of UMTS and LTE and camps on UTRAN Cell1 in Idle mode.
1.
UE1 makes a PS service in UTRAN cell1 and start FTP downloading. The service establish in CELL_DCH status.
Test Steps
2.
Stop FTP downloading, UE1 meets the channel status changes from CELL_DCH to inactive mode.
Anticipative Result
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3.
UE1 fast return to Cell2..
1.
In step3, UE1 performs the fast return to EUTRAN Cell2 before changes to idle status.
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Fast Return to LTE
6.3.3
Packet Service Fast Return to LTE for Active Mode
Table 6-3
Feature Validation Procedure 3
Test Item
Fast Return to LTE 1.
WCDMA and LTE system is ready.
2.
Cell1 supports HSUPA, HSDPA and DCH, Cell1 belongs to RNC1/NodeB1. Cell2 belongs to eNodeB1.
3. Preconditions
Configure Cell1 and Cell2 as adjacent cells with different coverage.
4.
Configure RNC support Fast Return to LTE function in CELL_DCH mode.
5.
UE1 with R8 or higher versions supports both of UMTS and LTE and camps on UTRAN Cell1 in Idle mode.
1.
UE1 makes a PS service in UTRAN cell1, the service establish in CELL_DCH status.
Test Steps 2.
When UE1 stays in UMTS Cell1 and satisfies a certain threshold, UE1 fast return to Cell2.
1. Anticipative Result
In step2, RNC send “RRCConnectionRelease” message with frequency of Cell2 and UE1 performs the fast return to EUTRAN Cell2 successfully.
6.3.4
Fast Return to LTE with Dedicated Priority for CSFB
Table 6-4
Feature Validation Procedure 4
Test Item
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Fast Return to LTE
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Fast Return to LTE
Test Item
Fast Return to LTE 1.
WCDMA and LTE system is ready.
2.
Cell1 supports HSUPA, HSDPA and DCH, Cell1 belongs to RNC1/NodeB1. Cell2 belongs to eNodeB1.
3. Preconditions
Configure Cell1 with dedicated frequency priority and Configure RNC support dedicated priority function.
4.
Configure RNC support Fast Return to LTE function.
5. UE1 with R8 or higher versions supports both of UMTS and LTE and camps on EUTRAN Cell2. 1.
UE1 makes a CS call to PSTN or another UE in EUTRAN cell2.
2.
ENodeB triggers the CSFB service from the Cell2 to Cell1, the
Test Steps
CS service establishes on UTRAN Cell1 3.
Release the CS call and then UE1 fast return to LTE by dedicated priority.
Anticipative Result
6.4
1.
In step3, UE1 performs the fast return to EUTRAN Cell2 successfully.
Feature Deactivation Procedure Table 6-5
RNC Parameter List
Managed Object. logic name
GUI Name
URncFunction.fastRetE
RNC Switch of Fast Return
UtranSwch
to E-UTRAN
Default
Deactivation
Value
Value
OFF
OFF
OFF
OFF
OFF
OFF
Switch of PS Service Fast UCelInfoFDD.csfbMulSr
Return to EUTRAN when
v2LteSw
CS is released for EUTRAN CSFB Multi-RAB Service
UtranCellFDD.csfbCsRe l2LteSw
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Switch of Fast Return to EUTRAN when EUTRAN CSFB CS is released
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Fast Return to LTE
Managed Object. logic
GUI Name
name
Default
Deactivation
Value
Value
Switch of Fast Return to UCelInfoFDD.dch2Fach RetLteSw
EUTRAN for PS Only when UE RRC Status
OFF
OFF
OFF
OFF
OFF
OFF
Transferring from CELL_DCH to CELL_FACH Switch of Fast Return to EUTRAN for PS when UE
UExtCelInfoFDD.pchIdle
RRC Status Transferring to
RetLteSw
PCH/IDLE (CELL_PCH/URA_PCH/idl e)
UExtCelInfoFDD.
PS in CELL_DCH Blind
dchPsBldRedLteSw
Fast Return to LTE Switch
For the above parameters’ description and configuration, please refer to chapter 6.2.
6.5
Impact on the Network
6.5.1
ZWF21-03-111 Fast Return to LTE
Advantages of this feature: Because the UEs supporting LTE will be handed over to LTE as far as possible, the number of the attempted handover and redirection will be increased, and the users experience will be improved.
Disadvantages of this feature: None
6.5.2
ZWF21-03-112 Packet Service Fast Return to LTE for Inactive Mode
Advantages of this feature:
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Fast Return to LTE
Because the UEs supporting LTE will be handed over to LTE as far as possible, the number of the attempted handover and redirection will be increased, and the users experience will be improved.
Disadvantages of this feature: None
6.5.3
ZWF21-03-113 Packet Service Fast Return to LTE for Active Mode
Advantages of this feature: Because the UEs supporting LTE will be handed over to LTE as far as possible, the number of the attempted handover and redirection will be increased, and the users experience will be improved.
7
Disadvantages of this feature:
Abbreviation Abbreviation
Full Name rd
3GPP
3 Generation Partnership Project
CS
Circuit Switch
CSFB
Circuit Switched Fallback
EUTRAN
Evolved Universal Terrestrial Radio Access Network
KPI
Key Performance Indicator
LTE
Long Term Evolution
PS
Packet Switch
RNC
Radio Network Controller
SRNC
Serving Radio Network Controller
SRVCC
Single Radio Voice Call Continuity
UMTS
Universal Mobile Telecommunications System
UTRAN
Universal Terrestrial Radio Access Network
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