Nemo Drive Test on 2G/3G Networks
Nemo Drive Test on 2G/3G
Networks
Toha Ardi Nugraha
Network Optimization Process
@maestoe
Reason of Drive Test?
1.
2.
3.
4.
Network Performance Monitoring
Maintenance
Benchmarking
Customer Complains
@maestoe
•
•
•
•
•
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)
@maestoe
Module 1
OVERVIEW 3G SYSTEM
Data Transmission
@maestoe
GSM & UMTS Evolution
@maestoe
3G/UMTS Architectures (Migration)
@maestoe
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
@maestoe
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)
@maestoe
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
@maestoe
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)
@maestoe
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)
@maestoe
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
@maestoe
GSM Channelization
• Physical Channel
– 200 Khz (Frequency Carrier) consist of 8 TS
• Logical Channel
– Control Channel
– Traffic Channel
Control
Channel
Traffic
Channel
@maestoe
GSM channelization (Cont’d)
Logical
channel
Chontrol
Channel
Broadcast
channel
Common
Control
Channel
Traffic
Channel
Dedicated
Control
Channel
Full Rate
Half rate
@maestoe
3G/UMTS Concept
•
•
•
•
WCDMA Concept
UMTS Architecture
Channelization
Handover
@maestoe
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
@maestoe
UMTS Radio Frequency Ranges
• FDD (Frequency Division Duplex)
• TDD (Time Division Duplex)
@maestoe
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
@maestoe
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
@maestoe
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
@maestoe
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
@maestoe
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)
@maestoe
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
@maestoe
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
@maestoe
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
@maestoe
Reason of Drive Test?
•
•
•
•
Network Performance Monitoring
Maintenance
Benchmarking
Customer Complains
@maestoe
Continuous Drive Test
• Drive Test (outdoor)
– GPS
• Walk Test (indoor)
– Pin point/way point
@maestoe
Analyze Data Collection
• Analyze data that was collected before
(from Log files)
• To know some problems in current area
@maestoe
Reporting
• To Answer Analyze Data Collection (Objective
Answer)
• Optimization Consideration
• Recommendation
@maestoe
Parameters DT GSM
1.
2.
3.
4.
5.
6.
Rx Level
Rx Qual
SQI
Cell Id, BSIC
TA (Timing Advance)
ARFCN, etc
@maestoe
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
@maestoe
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”.
@maestoe
Open Device Manager
• Step 3 :
• Look port to
conect hardware
(Modem)
• Scanner/GPS &
Check COM
Ports
@maestoe
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:
@maestoe
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
@maestoe
Running Program
Start >Program Files > Nemo Tools > Nemo Outdoor 5
•
•
•
•
Workspace
Details
Device Configuration
Load a measurement
@maestoe
User Interface Nemo Outdoor 5
Device
graph
Worksheet
@maestoe
Load Workspace
•
Step 3: Browse to Nemo Workspace Folder -> Select “workspace” >
Click “Open”.
@maestoe
Create Workspace
• Parameter
@maestoe
Add Devices
•
Step 1: Go to “Measurement” workspace > “Add New Device”.
•
Step 2: Click the “Configuration” part
> “Trace port” and “Modem port”
@maestoe
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)
@maestoe
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
@maestoe
Export to Map Info
@maestoe
Select Parameters
@maestoe
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
@maestoe
Open Log files
•
Example file (.tab)
@maestoe
Layer Control
• Command:
– View
– Edit
@maestoe
Create Symbol
@maestoe
Create Thematic Map
@maestoe
Create Thematic Map (Cont.'s)
@maestoe
Create Thematic Map (Cont.'s)
@maestoe
Reporting with Map Info
@maestoe
Open Table
@maestoe
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
@maestoe
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.
@maestoe
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)
@maestoe
Problem Signature
• Missing Neighbor or No Neighbors defined for
Site. (Database)
• Poor Coverage Area.
• Pilot Pollution Area
@maestoe
Poor Coverage Area
•
•
•
•
•
Test mobile measurements
Antenna configuration check
Verification of RF network design
Propagation model verification
Link budget analysis
@maestoe
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
@maestoe
Pilot Pollution
• Active set UE > 3 and in range 5 dB or approximately 3
dB from the biggest active set.
• Reduce system performance,
@maestoe
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
@maestoe
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
@maestoe
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
@maestoe
Type Antenna Down tilt
Mechanical down tilt
–
Physic, Sectoral
Electrical down tilt
–
Easy
0°
Electrical
0°
Mechanical
@maestoe
Typical antenna beam pattern
@maestoe
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
@maestoe
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
@maestoe
Thanks
Networks
Toha Ardi Nugraha
Network Optimization Process
@maestoe
Reason of Drive Test?
1.
2.
3.
4.
Network Performance Monitoring
Maintenance
Benchmarking
Customer Complains
@maestoe
•
•
•
•
•
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)
@maestoe
Module 1
OVERVIEW 3G SYSTEM
Data Transmission
@maestoe
GSM & UMTS Evolution
@maestoe
3G/UMTS Architectures (Migration)
@maestoe
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
@maestoe
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)
@maestoe
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
@maestoe
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)
@maestoe
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)
@maestoe
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
@maestoe
GSM Channelization
• Physical Channel
– 200 Khz (Frequency Carrier) consist of 8 TS
• Logical Channel
– Control Channel
– Traffic Channel
Control
Channel
Traffic
Channel
@maestoe
GSM channelization (Cont’d)
Logical
channel
Chontrol
Channel
Broadcast
channel
Common
Control
Channel
Traffic
Channel
Dedicated
Control
Channel
Full Rate
Half rate
@maestoe
3G/UMTS Concept
•
•
•
•
WCDMA Concept
UMTS Architecture
Channelization
Handover
@maestoe
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
@maestoe
UMTS Radio Frequency Ranges
• FDD (Frequency Division Duplex)
• TDD (Time Division Duplex)
@maestoe
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
@maestoe
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
@maestoe
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
@maestoe
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
@maestoe
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)
@maestoe
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
@maestoe
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
@maestoe
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
@maestoe
Reason of Drive Test?
•
•
•
•
Network Performance Monitoring
Maintenance
Benchmarking
Customer Complains
@maestoe
Continuous Drive Test
• Drive Test (outdoor)
– GPS
• Walk Test (indoor)
– Pin point/way point
@maestoe
Analyze Data Collection
• Analyze data that was collected before
(from Log files)
• To know some problems in current area
@maestoe
Reporting
• To Answer Analyze Data Collection (Objective
Answer)
• Optimization Consideration
• Recommendation
@maestoe
Parameters DT GSM
1.
2.
3.
4.
5.
6.
Rx Level
Rx Qual
SQI
Cell Id, BSIC
TA (Timing Advance)
ARFCN, etc
@maestoe
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
@maestoe
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”.
@maestoe
Open Device Manager
• Step 3 :
• Look port to
conect hardware
(Modem)
• Scanner/GPS &
Check COM
Ports
@maestoe
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:
@maestoe
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
@maestoe
Running Program
Start >Program Files > Nemo Tools > Nemo Outdoor 5
•
•
•
•
Workspace
Details
Device Configuration
Load a measurement
@maestoe
User Interface Nemo Outdoor 5
Device
graph
Worksheet
@maestoe
Load Workspace
•
Step 3: Browse to Nemo Workspace Folder -> Select “workspace” >
Click “Open”.
@maestoe
Create Workspace
• Parameter
@maestoe
Add Devices
•
Step 1: Go to “Measurement” workspace > “Add New Device”.
•
Step 2: Click the “Configuration” part
> “Trace port” and “Modem port”
@maestoe
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)
@maestoe
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
@maestoe
Export to Map Info
@maestoe
Select Parameters
@maestoe
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
@maestoe
Open Log files
•
Example file (.tab)
@maestoe
Layer Control
• Command:
– View
– Edit
@maestoe
Create Symbol
@maestoe
Create Thematic Map
@maestoe
Create Thematic Map (Cont.'s)
@maestoe
Create Thematic Map (Cont.'s)
@maestoe
Reporting with Map Info
@maestoe
Open Table
@maestoe
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
@maestoe
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.
@maestoe
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)
@maestoe
Problem Signature
• Missing Neighbor or No Neighbors defined for
Site. (Database)
• Poor Coverage Area.
• Pilot Pollution Area
@maestoe
Poor Coverage Area
•
•
•
•
•
Test mobile measurements
Antenna configuration check
Verification of RF network design
Propagation model verification
Link budget analysis
@maestoe
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
@maestoe
Pilot Pollution
• Active set UE > 3 and in range 5 dB or approximately 3
dB from the biggest active set.
• Reduce system performance,
@maestoe
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
@maestoe
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
@maestoe
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
@maestoe
Type Antenna Down tilt
Mechanical down tilt
–
Physic, Sectoral
Electrical down tilt
–
Easy
0°
Electrical
0°
Mechanical
@maestoe
Typical antenna beam pattern
@maestoe
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
@maestoe
Reference
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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
@maestoe
Thanks