Message Tracing and Performance Monitoring
MML Command
4.27 WRFD-150219 Coverage Based PS Redirection from UMTS to LTE (New/Optional)
4.27.1 Feature Description
This feature enables the RNC to redirect a UMTS/LTE dual-mode UE processing only PS services to the LTE network when:
The UE is located in the hybrid network coverage of UMTS and LTE.
The UMTS signal quality received at the UE is poor.
The LTE signal quality received at the UE is good.
When the UMTS signal quality received at the UE is very poor, the RNC can redirect the UE to the LTE network through blind redirection.
This feature provides the following benefits:
This feature provides an alternative to the PS handover. When UEs, the UMTS network, or the LTE network does not support the UMTS-to-LTE PS handover, this feature enables PS redirection to the LTE network.
When the UMTS signal quality is poor but the LTE signal quality is good, this feature allows the UE to be redirected to the LTE network, which ensures the continuity of PS services.
When the UMTS signal quality is very poor, this feature allows blind redirection to the LTE network, reducing service drops.
During UE redirection to the LTE network, this feature allows the RNC to obtain the LTE frequency from the system information or from the neighboring LTE cell. If the RNC obtains the LTE frequency from the system information, operators can eliminate the workload for configuring the neighboring LTE cell.
4.27.2 System Capacity and Network Performance
System Capacity
No impact.
Network Performance
When the UMTS signal quality is poor but the LTE signal quality is good, this feature allows the UE to be redirected to the LTE network, which ensures the continuity of PS services.
Compared with PS handover, PS redirection shortens the duration of service interruptions.
When the blind redirection switch is turned on in an area with poor LTE network coverage, call drops may occur.
4.27.3 NEs
This feature is implemented on the RNC.
This feature requires support from the UE. The UE must support UMTS and LTE and support 3GPP Release 8 or later.
4.27.4 Hardware
No impact.
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4.27.5 Inter-NE Interfaces
No impact.
4.27.6 Operation and Maintenance
License
An RNC-level license control item has been added to the RNC for this feature.
Configuration Management
The following MML commands have been introduced on the RNC side to accommodate this feature, as described in Table 4-36. No MML command has been introduced on the NodeB side.
Table 4-36 RNC MML commands Change
Type
MO MML Command Description
New UU2LTEHOCO
V
SET
UU2LTEHOCOV
This new command is used to set the RNC-level UMTS-to-LTE handover or redirection
measurement algorithm parameters.
Coverage-based handovers and redirections are triggered by any event except event 2D, event 2F and event 1F.
The event-triggered reporting mode and periodical reporting mode are both available to measurement reporting for the coverage-based handover to LTE.
New UU2LTEHOCO V
LST
UU2LTEHOCOV
This new command is used to list the RNC-level UMTS-to-LTE handover or redirection
measurement algorithm parameters.
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Type
MO MML Command Description
New UU2LTEHOCO V
ADD
UCELLU2LTEH OCOV
This new command is used to add cell-level measurement algorithm parameters for coverage-based UMTS-to-LTE handovers and redirections.
Coverage-based handovers and redirections are triggered by any event except event 2D, event 2F and event 1F.
The event-triggered reporting mode and periodical reporting mode are both available to measurement reporting for the coverage-based handover to LTE.
This new command is used to modify cell-level measurement algorithm parameters for coverage-based UMTS-to-LTE handovers and redirections.
Coverage-based handovers and redirections are triggered by any event except event 2D, event 2F and event 1F.
The event-triggered reporting mode and periodical reporting mode are both available to measurement reporting for the coverage-based handover to LTE.
This new command is used to remove cell-level measurement algorithm parameters for coverage-based UMTS-to-LTE handovers and redirections.
New UU2LTEHOCO V
LST
UCELLU2LTEH OCOV
This new command is used to list cell-level measurement algorithm parameters for coverage-based UMTS-to-LTE handovers and redirections.
The following parameters have been introduced on the RNC side to accommodate this feature, as described in Table 4-37. No parameter has been introduced on the NodeB side.
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Change Type
MO Parameter ID MML Command Description
New UCORR
This new parameter specifies whether to enable a coverage-based UMTS-to-LTE PS
redirection. When the switch is turned on, the RNC allows the coverage-based UMTS-to-LTE PS redirection procedure.
New UU2LT
This new parameter specifies the Ec/N0 threshold for a UE to start LTE cell measurements.
When the measured Ec/N0 is below the threshold, the UE reports event 2D. Then, the RNC sends a signaling
message to enable the compressed mode and the UE starts LTE cell measurements. Event 2D and event 2F are triggered to enable and disable the compressed mode respectively. To enable the compressed mode earlier, increase the threshold of triggering event 2D; otherwise, decrease the threshold of triggering event 2D. To prevent frequent ping-pong handovers at intervals between
enabling and disabling the compressed mode, increase the difference between the thresholds of triggering event 2D and event 2F. Thresholds of triggering event 2D and event 2F are unique for inter-frequency UMTS cells, GSM cells, and LTE cells.
When LTE cells and inter-frequency UMTS cells coexist, use the
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Type
MO Parameter ID MML Command Description
thresholds of triggering event 2D and event 2F in UMTS.
When LTE cells and GSM cells coexist, use the thresholds of triggering event 2D and event 2F in GSM.
When inter-frequency UMTS cells, GSM cells, and LTE cells coexist, use the thresholds based on the value of
CoexistMeasThdChoice in the ADD
UCELLHOCOMM/SET