Nemo Drive Test on 2G/3G
Networks
Reason of Drive Test?
1. Network Performance Monitoring 2. Maintenance
3. Benchmarking
•
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)
OVERVIEW 3G SYSTEM
Specification of GSM
• Frequency band :
Uplink 890 – 915 Mhz Downlink 935 – 960 Mhz
• Duplex spacing : 45 Mhz
• Carrier spacing : 200 khz
• Modulation : GMSK
GSM network Architecture (cont’d)
•
3 Subsystem in GSM network
- BSS (Base Station Subsystem)- NSS (Network and Switching Subsystem)
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
GSM network Architecture (cont’d)
NSS (Network and Switching Sub System)
GSM network Architecture (cont’d)
Operation and Support System
•
Control and Monitor the Network
- NMC (Network Management Centre)
- Some OMC are controlled by NMCGSM Frequency Bands
GSM type Frequency Band
Uplink (UL) Downlink (DL)
GSM Channelization
•
Physical Channel
–
200 Khz (Frequency Carrier) consist of 8 TS
•
Logical Channel
–
Control Channel
–
Traffic Channel
Control Channel
GSM channelization (Cont’d)
Logical channel Chontrol Channel Broadcast channel Common Control Channel Dedicated Control Channel Traffic Channel3G/UMTS Concept
•
WCDMA Concept
•
UMTS Architecture
•
Channelization
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
UMTS Radio Frequency Ranges
• FDD (Frequency 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
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)
Handover Concept
Site B 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
Handover: Types (3G)
• Intra-System handovers
– Intra-frequency handovers
• Soft, Softer
– Inter-frequency handovers
• Hard
• Inter-System handovers
– Handover between
WCDMA <> GSM (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
Soft Handover Algorithm
AS_Th – AS_Th_Hyst
As_Rep_Hyst
As_Th + As_Th_Hyst
Cell 1 Connected
Event 1A Add Cell 2
Event 1C
Replace Cell 1 with Cell 3
Event 1B Remove Cell 3 CPICH 1 CPICH 2 CPICH 3 Time Measurement Quantity
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
Continuous Drive Test
• Drive Test (outdoor) – GPS
Analyze Data Collection
•
Analyze data that was collected before
(from Log files)
Reporting
•
To Answer Analyze Data Collection (Objective
Answer)
•
Optimization Consideration
Parameters DT GSM
1. Rx Level
2. Rx Qual
3. SQI
4. Cell Id, BSIC
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
• Step 1:
Start >“Settings”> “Control Panel” > “System”
Or “My Computer” >
“Manage” > “Device Manager”
Open Device Manager
• Step 2: Choose “Hardware”
Tab in System Properties >
Open Device Manager
• Step 3 :
• Look port to
conect hardware (Modem)
• Scanner/GPS & Check COM
Connect UE & Check COM Ports
• Double click the “3G Modem” to check Trace
port number > Check
under “Modem” Tab.
• For UE Modem:
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.
Running Program
Start >Program Files > Nemo Tools > Nemo Outdoor 5
• Workspace
• Details
• Device Configuration
User Interface Nemo Outdoor 5
Worksheet
Load Workspace
• Step 3: Browse to Nemo Workspace Folder -> Select “workspace” >
Create Workspace
@maestoe
Add Devices
• Step 1: Go to “Measurement” workspace > “Add New Device”.
Nemo Interface
• Map Interface – Open map (.tab)
• Nemo logfiles and other files are stored proper folder for easy access, eg.
DRIVE TEST ON FIELD (OUTDOOR)
REPORTING
Map Info
• Exporting from Nemo Outdoor – Select Parameters
• Reporting KPI with Map Info
• Layer Control – Symbol
• Create Thematic Map
• Define Network Performance
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
Open Log files
Layer Control
•
Command:
ANALYSIS (TUNING THE NETWORK)
UMTS Optimization
• 3 Mayor Steps in Optimizing Network
• UMTS performance indicator
• Problem Signature
• Tuning network
– Specific Neighbor list
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.
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)
Problem Signature
•
Missing Neighbor or No Neighbors defined for
Site. (Database)
Poor Coverage Area
•
Test mobile measurements
•
Antenna configuration check
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
Pilot Pollution
• Active set UE > 3 and in range 5 dB or approximately 3 dB from the biggest active set.
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
Tuning the Network
Solution (Antenna Adjustments) Include :
– Down tilting
– Antenna Height
– Azimuth
– Type of antenna Reason of Down tilting:
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,
Type Antenna Down tilt
Mechanical down tilt
– Physic, Sectoral Electrical down tilt
– Easy
0 ° 0 °
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
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
