This section lists cell trace features and explains how to use tracing.
3.2.1 Trace features
This section lists all features related to cell trace functionality.
Table 12 Trace features
Feature Release
LTE163: Subscriber and Equipment Trace RL20
LTE433: Cell Trace RL20
LTE459: LTE Timing Advance Evaluation RL30 LTE644: Configurable Cell Trace Content RL30
LTE162: Cell Trace with IMSI RL40
LTE953: MDT (Minimization of Drive Test) RL40 LTE1340: Trace-based Real Time Monitoring RL40 LTE1457: Cell trace Configuration via Configuration
Management
RL40
LTE1687: Basic Layer3 Data Analyzer (L3DA) for LTE RL50 LTE1501: Measurement Report (MR) addition to cell
3.2.1.1 LTE163: Subscriber and Equipment Trace
This feature provides detailed, subscriber-oriented information at a call-level for one or more specific UEs. The subscriber and equipment trace supports the tracing of IMSI or IMEI numbers. The traces are activated on demand. The operator can activate
subscriber and equipment tracing for a limited period for the purpose of specific analysis, for example:
• root cause determination of a malfunctioning mobile
• advanced troubleshooting
• optimization of resource usage and quality
• RF coverage control and capacity improvement
• dropped call analysis
• E2E procedure validation
For more details, see LTE163: Subscriber and Equipment Trace.
3.2.1.2 LTE433: Cell Trace
With this feature, it is possible to follow the ongoing connections in a cell and to verify the intended functions within a cell. All UEs in a target cell that are in the connected state are traced simultaneously. This feature is also used for a more extensive analysis of a problem when various performance measurements do not give a clear indication of the problem. For more details, see LTE433: Cell Trace.
3.2.1.3 LTE459: LTE Timing Advance Evaluation
With this feature, the Timing Advance (TA) values are added to trace reports. Depending on the configuration, the TA values are added to vendor-specific extension tracing of the subscriber trace (LTE163: Subscriber and Equipment Trace) or the cell trace (LTE433:
Cell Trace). For more details, see LTE459: LTE Timing Advance Evaluation.
3.2.1.4 LTE644: Configurable cell trace content
This feature allows the operator to configure specific messages to be traced for each selected interface. For more details, see LTE644: Configurable cell trace content.
3.2.1.5 LTE162: Cell Trace with IMSI
With this feature, the existing cell trace data reports are mapped with the IMSI/IMEI numbers of the UEs located in the traced cell. This feature extends the scope of the LTE433: Cell Trace feature. The current LTE433: Cell Trace feature remains unchanged.
For more details, see LTE162: Cell Trace with IMSI.
3.2.1.6 LTE953: MDT (Minimization of Drive Test)
This feature is introduced as an alternative to expensive drive tests performed during network deployment and optimization. It offers a predefined set of MDT profiles available at the NetAct TraceViewer application. The profiles are defined to detect and monitor potential coverage problems. The solution is based on the data collected using the following features:
• LTE433: Cell Trace
• LTE644: Configurable cell trace content
• LTE570: Periodic UE Measurements
For more details, see LTE953: MDT (Minimization of Drive Test).
3.2.1.7 LTE1340: Trace-based Real Time Monitoring
This feature introduces a real-time network monitoring solution that is based on:
• trace data collected from multiple eNBs
• L3 Data Collector (L3DC) network element that acts as a trace collection entity in tracing
• Traffica is used for visualizing the collected data
For more details, see LTE1340: Trace-based Real Time Monitoring.
3.2.1.8 LTE1457: Cell trace Configuration via Configuration Management
The LTE1457: Cell trace Configuration via Configuration Management feature allows the operator to configure the cell trace using NetAct Configuration Management (CM) and the BTS Site Manager. This solution is an alternative to the existing method using NetAct TraceViewer application.
For more details, see LTE1457: Cell trace Configuration via Configuration Management.
3.2.1.9 LTE1687: Basic Layer3 Data Analyzer (L3DA) for LTE
The LTE1687: Basic Layer3 Data Analyzer (L3DA) for LTE feature introduces the Layer 3 Data Analyzer (L3DA), which is a tool for analyzing Flexi Multiradio BTS trace data. The LTE L3DA allows the operator to visualize and analyze the cell trace data collected in the L3 Data Collector (L3DC).
For more details, see LTE1687: Basic Layer3 Data Analyser (L3DA) for LTE.
3.2.2 Cell trace content
Cell trace data consists of:
• S1 Interface: S1AP data – context management – handover signaling
– UE capability info indication
– E-RAB management – NAS transport – location reporting – error indication
• X2 Interface: X2AP data – basic X2 mobility – error indication
• Uu Interface: RRC data – RRC connection signaling – counter check
– inter-RAT mobility – measurements – UE capability
– UL/DL information transfer
g
Note: The user plane is not traced.3.2.3 Activating cell trace in BTS Site Manager
This procedure shows how to activate the LTE433: Cell Trace feature using the BTS Site Manager.
Before you start
g
Note: To activate the feature on a wider scale, create a plan using the NetAct Configurator.Procedure
1 Set the LNBTS: Activate cell trace parameter to true.
During commisioning
• go to the Radio Network Configuration page
• expand MRBTS object
• select LNBTS object
• set Activate cell trace parameter to true
To activate other trace-related features, set the following parameter values to true:
• LNBTS: Activate cell trace with IMSI
• LNBTS: Activate MDT cell trace
• LNBTS: Activate subscriber and equipment trace
2 Create an MTRACE object.
To create MTRACE object:
• expand LNBTS object
• right click CTRLTS object and creat new MTRACE object
The CRTLTS object contains the basic trace parameters. Every active cell trace session equals one MTRACE object.
3 Configure the MTRACE object parameters.
To view the cell trace data in another tool than the NetAct, put the appropriate address in MTRACE:Trace collection entity IP address.
4 Set TA tracing to true.
• MTRACE object
• select Cell vendor specific tracing object
• set Cell TA tracing to true
The Timing Advance information is useful for troubleshooting.
Result
The cell trace data can be viewed with the NetAct Traceviewer, L3DA, or Traffica.
3.2.4 Viewing and analyzing cell trace data using L3DA
The following procedure shows how to use the L3DA application.
Purpose
The cell trace analysis platform consists of the following features:
• LTE1340: Trace-based Real Time Monitoring
Introduction of the L3 Data Collector (L3DC) and the function of sending cell trace data to Traffica
• LTE1687: Basic Layer3 Data Analyzer (L3DA) Introduction of the L3 analysis function
• LTE1909: BTS Diagnostics Toolkit A set of events for snapshot triggering
Typical call processing problems analyzed using the L3DA:
• call setup problems
• call drops
• handover failures
Before you start
To collect the cell trace data, the LTE433: Cell Trace feature needs to be configured.
Procedure
1 Start the cell trace.
To view the traces in L3DA, the L3DC IP address needs to be included in the cell trace configuration. The cell trace configuration is done with the BTS Site Manager or the TraceViewer application. The L3DC needs to be selected as the Trace Collection Entity during the cell trace configuration (the L3DC’s IP address put as the
tceIpAddress parameter value).
2 Open the L3DA.
To manage sacks and profiles, go to Environment > Change sack and profile (SCREEN). Select the one you need and click Load. To configure your log paths (and other preferences) go to Tools > Options.
3 Identify problematic calls by checking the ‘Out cause’ column.
Every call scenario is displayed in one row. They can be grouped by clicking on one of the columns in the main window (move the cursor on the column to see its description). The grouping helps to locate common root causes for failed events.
Columns useful for troubleshooting:
• Out Cause
Examples of abnormal call releases:
– No UE Reply – No EPC Messages – No UE Messages – Radiolink Failure – Re-est Reject
• Failure Phase Examples:
– RAB Active – RAB Setup – RAB Access – RRC Active – RRC Access
– Source S1 HO Setup – Target S1 HO Access
• Missing Reply Examples:
– RachPreamble – InitialUEMessage – rrcConnectionSetup
– securityModeCommand
• UE Distance
• HO Attempts
4 To view the scenario details right-click on the selected row and choose Trace View or Message view.
The Trace view shows the scenario in an L3 view, sequence view, or message view.
3.2.5 Tracing with NetAct
The NetAct Traceviewer application allows the user to activate and configure tracing.
For information on available tools and functions, refer to the NetAct operating documentation:
• TraceViewer Overview
• Tracing Subscribers and Equipment