10. 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)
11. 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
13. 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)
14. GSM Frequency Bands
Frequency Band
GSM type
Uplink (UL) Downlink (DL)
GSM 900 890-915 Mhz 935-960 Mhz
GSM 1800 (DCS 1800) 1710-1785 Mhz 1805-1880 Mhz
GSM 1900 (PCS 1900) 1850-1910 Mhz 1930-1990 Mhz
15. GSM Channelization
• Physical Channel
– 200 Khz (Frequency Carrier) consist of 8 TS
• Logical Channel
– Control Channel
– Traffic Channel
Control Traffic
Channel Channel
16. GSM channelization (Cont’d)
Logical
channel
Chontrol Traffic
Channel Channel
Common Dedicated
Broadcast
Control Control Full Rate Half rate
channel
Channel Channel
18. 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
19. UMTS Radio Frequency Ranges
• FDD (Frequency Division Duplex)
• TDD (Time Division Duplex)
20. 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
21. 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
22. Handover Concept
BSC
Handover Req Handover
Acknowledge Request
Handover Req
Handover Req Acknowledge
Acknowledge
Handover
Handover
command
Complete
Handover
Request
Posisi 2
Site B Posisi 1 Site A
Posisi 3
23. 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
25. 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
34. 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
35. 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”.
36. Open Device Manager
• Step 3 :
• Look port to
conect hardware
(Modem)
• Scanner/GPS &
Check COM
Ports
37. 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:
38. 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 ToolsNemo OutdoorWorkspaces
47. Map Info
• Exporting from Nemo Outdoor
– Select Parameters
• Reporting KPI with Map Info
• Layer Control
– Symbol
• Create Thematic Map
• Define Network Performance
• Open Table
50. 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
60. UMTS Optimization
• 3 Mayor Steps in Optimizing Network
• UMTS performance indicator
• Problem Signature
• Tuning network
– Specific Neighbor list
– Managing excessive soft handoff
61. 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.
63. Problem Signature
• Missing Neighbor or No Neighbors defined for
Site. (Database)
• Poor Coverage Area.
• Pilot Pollution Area
64. Poor Coverage Area
• Test mobile measurements
• Antenna configuration check
• Verification of RF network design
• Propagation model verification
• Link budget analysis
65. 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
66. Pilot Pollution
• Active set UE > 3 and in range 5 dB or approximately 3
dB from the biggest active set.
• Reduce system performance,
67. 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
68. 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
69. 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
70. Type Antenna Down tilt
Mechanical down tilt
– Physic, Sectoral
Electrical down tilt
– Easy
0° 0°
Electrical Mechanical
72. 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
73. 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
