eHRPD/3GPP2
4.3 LTE498: RAN Information Management for GSM .1 Description of LTE498: RAN Information for GSM.1 Description of LTE498: RAN Information for GSM
Introduction to the feature
The LTE498: RAN Information for GSM feature allows the transfer of information between the source and target cell via the core network. This mechanism allows for a reduction of parameter setting.
4.3.1.1 Benefits
End-user benefits
During the following procedures:
• CSFB
• NACC
• normal redirection
to Global System for Mobile Communications (GSM), the GSM system information message is included in the RRCConnectionRelease and
MobilityFromEutranCommand messages. This feature reduces the time the UE uses to access the GSM network because the UE does not need to read the system information from GSM.
Operator benefits
This feature provides the operator with the following benefits:
• reducing the number of parameters needed to configure the network assisted cell change or the RRC connection release with redirect and SIB
4.3.1.2 Requirements
Software requirements
Table 12: Software requirements lists software required for this feature.
Table 12 Software requirements
System release Flexi Multiradio BTS Flexi Multiradio 10 BTS
OMS
RL60 LBTS6.0 LBTS6.0
-UE NetAct MME SAE GW
3GPP R8 UE capabilities NetAct8 EP1 -
-Hardware requirements
This feature requires no new or additional hardware.
4.3.1.3 Functional description
Figure 3 RIM protocol structure between E-UTRAN and GERANeNB MME
(controlling) SGSN BSC
(serving)
The systemInfoListGeran optional parameter contains SI that is manually entered.
The systemInfoType parameter, set by the operator, indicates which type of GERAN System Information (if any) is included in the RRC
MOBILITYFROMEUTRANCOMMAND message.
The systemInfoType and systemInfoListGeran parameters become meaningless under the same conditions, that is:
• if the LTE498: RAN Information Management for GSM feature is activated and
• the PLMN of the cell is not blacklisted for RIM and
• the gTargetRac parameter is configured The following RIM procedures are supported:
• RAN Information Request/Multiple Report procedure
• RAN Information Send procedure
• RAN Information Application Error procedure
• RAN Information Error procedure
The LTE498: RAN Information Management for GSM feature allows the eNB to receive GERAN SIB information from BSC without the need for configuration of GERAN SIBs by the operator.
The received GERAN SIBs are used during eNACC to GSM (the LTE442: Network Assisted Cell Change to GSM feature), and during enhanced UE Context Release with Redirect to GSM for CS fallback and/or the "normal" redirect (the LTE984: GSM Redirect with System Information feature).
Support of Direct Information Transfer via S1 interface
To transmit RIM information between the eNB and the MME, two following procedures are supported:
• the eNB Direct Information Transfer procedure
to transmit an information container from the eNB to the MME
• the MME Direct Information Transfer procedure
to transmit an information container from the MME to the eNB Blacklisting GSM PLMNs for RIM
In case of multi-operator configurations, the RIM might not be supported by all GSM networks. It is possible to blacklist the GSM PLMNs to avoid periodical attempts to establish RIM associations. The Blacklisted GSM PLMNs for RIM
(blacklistedGsmPlmnsForRim) parameter allows blacklisting of RIM for all GERAN neighbor cells belonging to one of the configured PLMNs. If the
blacklistedGsmPlmnsForRim parameter is omitted, the RIM applies for all GERAN neighbor cells of the eNB.
RIM interface status
The RIM interface status (rimStatus) parameter provides the status of the RIM association to a serving base station system (BSS). This parameter can have the values as follows:
• disabled
The GERAN neighbor cell is not RIM enabled. With the rimStatus=disabled, one of the following options happens:
– The LTE498: RAN Information Management for GSM feature is not activated.
– The PLMN of the GERAN cell is blacklisted for RIM.
– No RAC value is configured.
• unavailable
The GERAN neighbor cell is RIM-enabled but no valid system information from the RIM procedure is available.
• available
The GERAN neighbor cell is RIM-enabled and a valid system information from the RIM procedure is available.
4.3.1.4 System impact
Interdependencies between features
Activation of the LTE498: RAN Information Management for GSM feature is reasonable if at least one of the features: the LTE442: Network Assisted Cell Change to GSM or the LTE984: GSM Redirect with System Information is activated.
• LTE442: Network Assisted Cell Change to GSM
When both features: the LTE498: RAN Information Management for GSM and the LTE442: Network Assisted Cell Change to GSM are activated, then eNACC to GERAN procedure is populated with up-to-date system information acquired by RIM procedure.
• LTE984: GSM Redirect with System Information
When both features: the LTE498: RAN Information Management for GSM and the LTE984: GSM Redirect with System Information are activated, then GSM redirection procedure is populated with up-to-date system information acquired by RIM
procedure.
Impact on interfaces This feature impacts:
• the RRC protocol in the LTE-Uu interface
• the S1AP protocol in the S1-MME interface
Impact on network and network element management tools
This feature has no impact on network management or network element management tools.
Impact on system performance and capacity
This feature has no impact on system performance or capacity.
4.3.1.5 Management data
Alarms
Table 13: Modified alarms lists existing alarms related to this feature.
Table 13 Modified alarms
Alarm ID Alarm name
7657 BASE STATION CONNECTIVITY DEGRADED
The alarm is caused by the following BTS faults:
• RIM interface timeout
• RIM interface error
If an RIM association to a GERAN neighbor cell cannot be established after several attempts or if a RAN INFORMATION ERROR PDU is received or if an application error is detected in Application Container IE of RAN INFORMATION PDU or if Application Error Container IE is included in RAN INFORMATION PDU, the RIM interface timeout or RIM interface error fault is reported.
Only one fault can be reported per GERAN public land mobile network (PLMN). This avoids alarm floods and reporting of several alarms for the same root cause. The raised alarm remains active as long as there is an active fault for the PLMN even if the fault for
the cell, whose routing area code (RAC) and cell global identification (CGI) are reported in the alarm, has been cleared. Updating of alarm information is not required (a risk for message floods).
The RIM alarms do not suppress BASE STATION CONNECTIVITY DEGRADED alarms that are raised because of S1 and/or X2 interface failures.
Measurements and counters
There are no measurements and counters related to this feature.
Key performance indicators
There are no key performance indicators related to this feature.
Parameters
Table 14: New parameters lists parameters introduced with this feature.
Table 14 New parameters
Full name Abbreviated name Managed object Structure
RAC GERAN gTargetRac LNADJG
RIM interface status rimStatus LNADJG Activate RAN
Information
Management for GSM
actRIMforGSM LNBTS
Blacklisted GSM PLMNs for RIM
blacklistedGsmPlmnsF orRim
LNBTS
MCC mcc LNBTS blacklistedGsmPlmnsF
orRim
MNC mnc LNBTS blacklistedGsmPlmnsF
orRim
MNC length mncLength LNBTS blacklistedGsmPlmnsF
orRim Maximum RIR
attempts to GERAN
nRimRirG LNBTS
Timer to wait for next RI PDU from GERAN
tRimKaG LNBTS
Polling timer to ReStart RIR
Procedure to GERAN
tRimPollG LNBTS
Timer to wait for RIR Response from GERAN
tRimRirG LNBTS
Table 15: Related parameters lists existing parameters related with the feature.
Table 15 Related parameters
Name Abbreviation Managed object
System info list GERAN systemInfoListGeran LNADJG
Table 15 Related parameters (Cont.)
Name Abbreviation Managed object
System information type systemInfoType LNADJG
4.3.1.6 Sales information
Table 16 Sales information
BSW/ASW License control in network element
License control attributes
Activated by default
ASW SW Asset Monitoring - No
4.3.2 Activating LTE498: RAN Information Management for GSM
Before you start
Table 17 Parameters used for activating and configuring LTE498: RAN Information Management for GSM
Parameter Purpose Requires eNB restart or
object locking Activate RAN
Information
Management for GSM (actRIMforGSM)
activation flag no
RAC GERAN (gTargetRac)
optional configuration
g
Note: If it is not configured for the GERAN target cell, RAN Information Management (RIM) will not be used.no
Blacklisted GSM PLMNs for RIM (blacklistedGsmPlm nsForRim) parameter structure
optional configuration no
Maximum RIR
attempts to GERAN (nRimRirG)
mandatory configuration no
Timer to wait for next RI PDU from GERAN (tRimKaG)
mandatory configuration no
Polling timer to ReStart RIR
Procedure to GERAN (tRimPollG)
mandatory configuration no
Timer to wait for RIR Response from GERAN ( tRimRirG)
mandatory configuration no
Procedure
1 Follow the general procedure described in section Activating and deactivating LTE features using BTS Site Manager.
In Step 3 (Modify the feature-specific eNB configuration settings) of the general procedure, perform the steps described in this procedure.
2 Activate the feature.
a) Go to the Radio Network Configuration page.
b) Expand the MRBTS object.
c) Select the LNBTS object.
d) Set the Activate RAN Information Management for GSM (actRIMforGSM) parameter value to true.
3 Configure the RAC GERAN.
a) Go to the Radio Network Configuration page.
b) Expand the MRBTS object.
c) Right-click the LNBTS object.
d) Select New LNADJG.
e) For the LNADJG object set all the mandatory parameters' values.
f) Set the RAC GERAN (gTargetRac) parameter value.
4 Configure the parameters.
a) Go to the Radio Network Configuration page.
b) Expand the MRBTS object.
c) Select the LNBTS object.
d) Set the Maximum RIR attempts to GERAN (nRimRirG), Timer to wait for next RI PDU from GERAN (tRimKaG), Polling timer to ReStart RIR Procedure to GERAN (tRimPollG), Timer to wait for RIR Response from GERAN (tRimRirG) parameters’
values.
5 Send the parameters to the eNB according to the procedure described in section Activating and deactivating LTE features using BTS Site Manager.
Once RIM association is successfully established, the RIM interface
status (rimStatus) parameter, set by the system, is changed automatically to available. If RIM association is not established, alarm will be raised and the RIM interface status (rimStatus) parameter will be changed automatically to unavailable.
4.3.3 Deactivating LTE498: RAN Information Management for GSM
Procedure
1 Follow the general procedure described in section Activating and deactivating LTE features using BTS Site Manager.
In Step 3 (Modify the feature-specific eNB configuration settings) of the general procedure, perform the steps described in this procedure.
2 Deactivate the feature.
a) Go to the Radio Network Configuration page.
b) Expand the MRBTS object.
c) Select the LNBTS object.
d) Set the Activate RAN Information Management for GSM (actRIMforGSM) parameter value to false.
3 Send the parameters to the eNB according to the procedure described in section Activating and deactivating LTE features using BTS Site Manager.
The RIM interface status (rimStatus) parameter, set by the system, will be changed automatically to disabled for all LNADJG’s.