Nemo Drive Test on 2G/3G Networks Toha Ardi Nugraha Trainerr at Expert Coaching Clinic Traine
Network Optimization Process
Reason Reason of of Drive Drive Test? Test? 1.
Network Pe Performance Mo Monitorin ring
2.
Maintenance
3.
Benchmarking
4.
Customer Complains
• Module 1 : Overview 3G System (1 hour) • Module 2 : Drive Test Concept (1,5 hour) • Module 3 : Drive Test on Field (2,5 hour) • Module 4 : Reporting (2 hour) • Module 5 : Analysis (2 hour)
Module 1
OVERVIEW 3G SYSTEM
Data Transmission
GSM & UMTS Evolution
3G/UMTS Architectures (Migration)
Specification of GSM • Frequency band : Uplink
890 – 915 Mhz
Downlink
935 – 960 Mhz
• Duplex spacing
: 45 Mhz
• Carrier spacing
: 200 khz
• Modulation
: GMSK
• Access method
: FDMA / TDMA
GSM network Architecture (cont’d) • 3 Subsystem in GSM network - BSS (Base Station Subsystem) - NSS (Network and Switching Subsystem) - OSS/OMC (Operating and Support system or Operating and Maintenance Centre)
GSM network Architecture (cont’d) BSS (Base Station SubSystem) •
BTS (Base Transceiver Station) - Radio equipment - To transmit and Receive signal to MS - Defined a Cell coverage depend on the power transmit
•
BSC (Base Station Controller) - RRM for several BTS - Handover management
•
TRAU - Rate adaption
GSM network Architecture (cont’d) NSS (Network and Switching Sub System) • MSC (Mobile Switching Centre) • HLR (Home Location Register) • VLR (Visitor Location Register) • AuC (Authentication Center)
GSM network Architecture (cont’d) Operation and Support System • Control and Monitor the Network - NMC (Network Management Centre) - Some OMC are controlled by NMC
- OMC (Operation and Maintenance Centre)
GSM Frequency Bands
GSM type
Frequency Band Uplink (UL)
Downlink (DL)
890-915 Mhz
935-960 Mhz
GSM 1800 (DCS 1800)
1710-1785 Mhz
1805-1880 Mhz
GSM 1900 (PCS 1900)
1850-1910 Mhz
1930-1990 Mhz
GSM 900
GSM Channelization • Physical Channel – 200 Khz (Frequency Carrier) consist of 8 TS
• Logical Channel – Control Channel – Traffic Channel
Control Channel
Traffic Channel
GSM channelization (Cont’d)
Logical channel
Chontrol Channel
Broadcast channel
Common Control Channel
Traffic Channel
Dedicated Control Channel
Full Rate
Half rate
3G/UMTS Concept • WCDMA Concept • UMTS Architecture • Channelization • Handover
WCDMA - Wideband CDMA • Radio access technology for one of the UMTS access modes (UTRA FDD) using 5 MHz duplex channels. – Frame length is of 10 msec, Chip rate is 3.84 Mcps – All users share the same frequency and time domain – Users separated by the codes
UMTS Radio Frequency Ranges • FDD (Frequency Division Duplex) • TDD (Time Division Duplex)
Channelization in UMTS •
Logical Channel between RLC and MAC – Specific for information types – What type of data to be transferred
•
Transport channel between MAC and PHY – Specific for “how to transfer information?” (quality guarantee) – How and with which type of characteristic the data is transferred by the Physical Layer
•
Physical Channel –
Exact Physical characteristics of the radio channel
WCDMA Channel (Cont.'s) • Spreading means increasing the signal bandwidth • Spreading includes two operations – Channelization (increases signal bandwidth) • Orthogonal Spreading
– Scrambling (does not affect the signal bandwidth) • Use pseudo-noise codes
Handover Concept BSC
Handover Req Acknowledge
Handover Request Handover Req Acknowledge
Handover Req Acknowledge Handover Complete
Handover command Handover Request
Posisi 2
Site B
Posisi 3
Posisi 1
Site A
Handover: Types (2G) • Intracell handover – MS moves from one sector to another sector within same cell • IntraBSC handover – MS moves from cell to another cell within same BSC • IntraMSC handover – MS moves from cell to another cell from different BSC within same MSC • InterMSC handover – MS moves from cell to another cell from different BSC and different MSC
Handover: Types (3G) •
Intra-System handovers – Intra-frequency handovers • Soft, Softer – Inter-frequency handovers • Hard
•
Inter-System handovers – Handover between WCDMA <> GSM (Hard) – Handover between WCDMA/FDD <> TDD (Hard)
Pilots Set The handset considers pilots in sets – Active : pilot of sector actually in use – Candidate : pilots mobile requested, but not yet set up & transmitting by system – Neighbors: pilots told t mobile by system, as nearby sectors to check – Remaining: any pilots used by system but not already in the other sets
Soft Handover Algorithm T Measurement Quantity
T
T
CPICH 1
As_Th + As_Th_Hyst
AS_Th – AS_Th_Hyst
As_Rep_Hyst
CPICH 2
CPICH 3
Time
Cell 1 Connected
Event 1A Add Cell 2
Event 1C Replace Cell 1 with Cell 3
Event 1B Remove Cell 3
Module 2
DRIVE TEST CONCEPT
Network Environment •
UMTS Drive Test is testing and measuring performance of 3G/UMTS network.
•
Tools : 1. Software Nemo Outdoor 2. PC laptop 3. GPS 4. Scanner
Reason of Drive Test? • Network Performance Monitoring • Maintenance • Benchmarking • Customer Complains
Continuous Drive Test • Drive Test (outdoor) – GPS
• Walk Test (indoor) – Pin point/way point
Analyze Data Collection • Analyze data that was collected before (from Log files)
• To know some problems in current area
Reporting • To Answer Analyze Data Collection (Objective Answer) • Optimization Consideration • Recommendation
Parameters DT GSM 1. Rx Level 2. Rx Qual 3. SQI 4. Cell Id, BSIC 5. TA (Timing Advance) 6. ARFCN, etc
Parameters DT UMTS • UARFCN (UMTS Absolute Radio Frequency Channel Number) • RSCP (Receive Signal Code Power) • RSSI (Receive Signal Strength Indicator) • SC (Scrambling Code) • Ec/No • UE TxPower (dBm) • Throughput • BER, etc
Open Device Manager •
Step 1: Start >“Settings”> “Control Panel” > “System”
Or “My Computer” >
“Manage” > “Device Manager”
•
Step 2: 2: Ch Choose “H “Hardware” Tab in System Properties > Click “Device Manager”.
Open Device Manager • Step 3 : • Look port to conect hardware (Modem) • Scanner/GPS & Check COM Ports
Connect UE & Check COM Ports •
Double click the “3G Modem” to check Trace port number > Check under “Modem” Tab.
•
For UE Modem: – In device manager view:
Start Nemo Outdoor 5.07 and Load Workspace • Make sure the Nemo dongle is connected to the laptop. • Launch Nemo Outdoor 5.07. • Load the desired workspace. • Workspace should contains adequate information for the user to monitor. • Different workspace should be created for different setup configuration. • Nemo workspace are stored proper folder for easy access, eg. C:\Nemo Tools\Nemo Outdoor\Workspaces
Running Program Start >Program Files > Nemo Tools > Nemo Outdoor 5 •
Workspace
•
Details
•
Device Configuration
•
Load a measurement
User Interface Nemo Outdoor 5
Device
graph
Worksheet
Load Workspace •
Step 3: Browse to Nemo Workspace Folder - > Select “workspace” > Click “Open”.
Create Workspace • Parameter
Add Devices •
Step 1: Go to “Measurement” workspace > “Add New Device”.
•
Step 2: Click the “Configuration” part > “Trace port” and “Modem port”
Nemo Interface • Map Interface – Open map (.tab)
•
Nemo logfiles and other files are stored proper folder for easy access, eg. C:\Nemo Tools\Results (.nmf)
Module 3
DRIVE TEST ON FIELD (OUTDOOR)
Module 4
REPORTING
Map Info • Exporting from Nemo Outdoor – Select Parameters
• Reporting KPI with Map Info • Layer Control – Symbol
• Create Thematic Map • Define Network Performance • Open Table
Export to Map Info
Select Parameters
Report KPI With Mapinfo •
KPI (Key Performance Indicator) : key to detemaint Network performance. like as , RSCP, Ec/No, etc
•
Mapinfo is Software for loading and mapping geogharphic analysis
•
File > open file (chose file extention .tab)
•
Ex : bandung.tap
•
Used Layer control
Open Log files
•
Example file (.tab)
Layer Control • Command: – View – Edit
Create Symbol
Create Thematic Map
Create Thematic Map (Cont.'s)
Create Thematic Map (Cont.'s)
Reporting with Map Info
Open Table
Module 4
ANALYSIS (TUNING THE NETWORK)
UMTS Optimization • 3 Mayor Steps in Optimizing Network • UMTS performance indicator • Problem Signature • Tuning network – Specific Neighbor list – Managing excessive soft handoff
3 Mayor Steps in Optimizing Network • RF optimization is the process of measuring, • analyzing, and tuning and existing network to meet network performance criteria • It usually occurs after the network planning is completed • It can be performed frequently to respond: – Changes or growth in the network – Customer complaints such as coverage, dropped call etc. – The need to improve capacity.
UMTS Performance Indicator KPI Target : – RSCP (good > -85 dBm) – Ec/No ( > -8 dB) – BER (98%) – Analyze Pilot Pollution Area – Drop Call Rate (DCR) – HSR (Handover Success Rate) – Call Setup Success Rate (CSSR)
Problem Signature • Missing Neighbor or No Neighbors defined for Site. (Database) • Poor Coverage Area. • Pilot Pollution Area
Poor Coverage Area • Test mobile measurements • Antenna configuration check • Verification of RF network design • Propagation model verification • Link budget analysis
Improving coverage – Cell spliting, Sectorisation • Difficult , Expensive • Primarily used for capacity enhancement
– Overlaid cell structure • Micro- and picocells • Cellular repeaters RNC Node B Node B Node B Node B
Pilot Pollution • Active set UE > 3 and in range 5 dB or approximately 3 dB from the biggest active set. •
Reduce system performance,
Antenna Fine Tuning • Horizontal plane – Possible coverage weakness between sector – Interference reduction – Traffic load distribution
• Vertical Plane – Interference reduction – Possible coverage weakness in the short to medium distance range – Traffic load distribution
Tuning the Network Solution (Antenna Adjustments) Include : – Down tilting – Antenna Height – Azimuth – Type of antenna Reason of Down tilting: 1 Reduce interference 2 Optimizing cell
Antenna Configuration •
General points to check – antenna type, e.g. • omni • directional 60, 90 or 120 degrees • electrical downtilt
– antenna azimuth angle (for directional antenna) • coverage targets – antenna tilt angle • electrical + mechanical
– diversity & isolation • e.g. space diversity, • polarisation diversity
Type Antenna Down tilt Mechanical down tilt –
Physic, Sectoral
Electrical down tilt –
Easy
0°
Electrical
0°
Mechanical
Typical antenna beam pattern
Omni vs. Sectorised • OMNI cells - more difficult to optimize – Electrical down tilt possible, however • same for entire cell
– Parameters same for entire cell
• Directional antenna – narrower beam easier to control interference – tilting less efficient with wider beams Sectorised cell site with different downtilt angles
Reference •
Short Course “In Building DCS 1800 Coverage”, Mobile Communication Laboratory, 2009
•
Short Course “Drive Test UMTS”, Mobile Communication Laboratory, 2008
•
Short Course “Drive Test CDMA 2001x and Optimization”, Mobile Communication Laboratory, 2008
•
Short Course “CDMA Drive Test and Optimization”, Antenna Laboratory, 2007
•
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