60115416 3g RF optimization guideline

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 

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

SSV: Single Site Verification

3G Optimization

Top aspects of 3G optimization

 Coverage Optimization

 Call Drop Optimization

 Handover & Neighbors Optimization

 Quality -Interference & Pilot Pollution Optimization

1 Coverage

3G RSCP level

Good: RSCP ≥ -85 dBm

Fair: -95 dBm ≤ RSCP < -85 dBm

Poor: RSCP < - 95 dBm

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 Coverage Optimization

Ways to improve coverage in a network if any of the following issue occurs Ways to improve coverage in a network if any of the following issue occurs

I Poor coverage - RSCP

Ways to improve poor coverage

 Antenna tilt

 Antenna azimuth

 Antenna location

 Antenna height

 Antenna type

 Site location

 New site

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

 Antenna Adjustment - Azimuth

 Antenna down tilt

 Lower pilot CPICH power

V 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 Faulty Hardware

6 Pilot pollution

7 Signalling

2 Optimization of Call Drop

I Call drop due to Poor coverage- Low signal strength

Ways to Optimize

 Antenna tilt

 Antenna azimuth

 Antenna height

 Antenna type

 Antenna location

 Site location

 New site

II 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

 Check neighbor list from BSS engineer

 Add missing neighbor cells

 Remove unnecessary neighbor cells

IV Call drop due to Interference

Ways to resolve interference issue, in other to reduce call drop in a network and improve performance

 Resolve High RTWP –Receive total wideband power

 Change antenna azimuth in the affected area

 Check Feeder connector

 Check external interference if any

V 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 defined 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 Quality -Interference & Pilot Pollution Optimization

1 Identification and Optimization of pilot pollution

Below are the process or condition for the identification of 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