Nemo Drive Test on 2G/3G Networks Toha Ardi Nugraha Trainer at Expert Coaching Clinic
Network Optimization Process
Reason of Drive Test? 1. 2. 3. 4.
Network Performance Monitoring Maintenance Benchmarking 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. 2. 3. 4. 5. 6.
Rx Level Rx Qual SQI Cell Id, BSIC TA (Timing Advance) 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: Choose “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 • Nemo_Outdoor_manual
Thanks
