Technical Training on 3G RF Optimization
Optimization is to
•
Keep track of network
•
Improve quality of network
•
To provide best network quality using any available spectrum analyzer
•
Accessibility, Retainability, Mobility
CS – Circuit switch – voice
PS- Packet switch – Data services faster than 2G data service
Video = CS + PS
RSCP- Receive signal level of a particular CPICH (dbm)
Ec/Io – The CPICH quality
CPICH- Common Pilot indication channel – it is a broadcast for every cell
IRAT- Handover from 3G to 2G Inter Radio Access technology
Softer handover – Softer HO occur btw sector of the same site
Soft HO- Occur btw sectors of the different sites
3G Optimization
Top aspects of 3G optimization
•
Coverage Optimization
•
Call Drop Optimization
•
Handover & Neighbors Optimization
•
1. Coverage
Quality -Interference & Pilot Pollution Optimization
3G RSCP level
Good: RSCP ≥ -85 dBm
Fair:
-95 dBm ≤ RSCP < -85 dBm
Poor: RSCP < - 95 dBm
RSCP
3G Coverage-Q
-65
G
Radio
Good
R
-75
Ok
Coverage
Causes Poor Coverage
1. Poor coverage due to bad RSCP- Receive signal level <
-95dbm
2. Poor Coverage due to Missing neighbors & handover
failure
3. Faulty hardware.
4. Interference
1.
-85
Coverage Optimization
Ways to improve coverage in a network if any of the following issue occurs
In
C
Ways to improve coverage in a network if any of the following issue occurs
C
I. Poor coverage - RSCP
Ways to improve poor coverage
-95
•
•
•
•
•
•
•
Antenna tilt
Antenna azimuth
Antenna location
Antenna height
Antenna type
Site location
New site
Coverage
w
II.
High interference and hence poor Ec/Io – High RTWP
Ways to resolve high interference in other to improve coverage
•
•
•
•
Resolve High RTWP –Receive total wideband power
Change antenna azimuth
Check Feeder connector
Check external interference
III. Poor Coverage due to Missing neighbors
Ways to resolve missing neighbors in other to improve coverage
•
•
Add missing neighbor cells
Check neighbor list from BSS engineer.
IV. Poor Coverage due to Pilot Pollution (too many cells present )
Ways to resolve pilot pollution in other to improve coverage
•
•
•
V.
Antenna Adjustment - Azimuth
Antenna down tilt
Lower pilot CPICH power
Check hardware alarm, Loss of attenuation check – Feeders , connectors &
Jumper
2. Call Drop
Causes of call drop
1.
Poor coverage – Low signal strength
2. Handover failure
3. Missing Neighbors
4. Interference
5. Hardware Faulty
6.
Pilot pollution
7.
Signalling
2. Optimization of Call Drop
I. Call drop due to Poor coverage- Low signal strength
Ways to Optimize
•
•
•
•
•
•
•
II
Antenna tilt
Antenna azimuth
Antenna height
Antenna type
Antenna location
Site location
New site
Call drop due to Handover failure
Ways to optimize handover failure
•
•
•
•
•
Unavailable time slots because of high traffic – Increase time slot
Congestion – Increase Capacity
Low signal strength and bad quality
Check handover margin
Hardware problem like TRX or time slot problem
III Call drop due to Missing neighbor
Ways to optimize handover problem
•
•
•
IV
Check neighbor list from BSS engineer
Add missing neighbor cells
Remove unnecessary neighbor cells
Call drop due to Interference.
Ways to resolve interference issue, in other to reduce call drop in a
network and improve performance.
•
•
•
•
V
Resolve High RTWP –Receive total wideband power
Change antenna azimuth in the affected area.
Check Feeder connector
Check external interference if any
Call drop due to Pilot Pollution (too many cells present)
Ways to resolve pilot pollution issue, in other to reduce call drop in a
network and improve performance
•
•
•
Change Antenna Azimuth in the affected area
Antenna down tilt
Lower pilot CPICH power
VI Check hardware Alarm, Radio failure and Node B failure
V. Signaling - Run a Trace in the affected area
3. Neighbor Optimization
I. Neighbor relation should be well define to avoid call drop
3G to 3G – on 3G network RNC
3G to 2G – on 3G network RNC
2G to 3G – on 2G network BSC
II. Check neighbor list from BSS engineer
III. Add missing neighbor cells
IV Remove unnecessary neighbor cells.
3b
Handover Optimization Check Handover margin
4.
1.
Quality -Interference & Pilot Pollution Optimization
Identification and Optimization of pilot pollution
Below are the process or condition to identification Pilot pollution in a network
•
•
•
•
More than 3 Active set in a cluster
All active set CPICH_RSCP > -95dbm
The difference between first & last active set < 5dbm
Pilot Scrambling code contribution more than 8% of pilot pollution in a cluster
Below are the process to resolve or optimize pilot pollution
•
•
•
Antenna Adjustment - Azimuth
Antenna down tilt - By adjusting tilts on the best servers, or worst
interference, pilot pollution can be removed or reduced in a network
Lower pilot power