Site Optimization Process

1. Site Optimization is mainly done in Three stages:

• Hardware Optimization/Alarm Rectification

• Physical Optimization/Drive Test

• Parameter(Soft) Optimization

First step of the optimization is to start with basic site database verification with the planned one & Study of the KPI & MRR reports.

Flow Chart for Optimization:

1.1.Hardware Optimization/Alarm Rectification:

Inputs for the Process are:

1..1.1. Drive Testing/Physical Optimization

1..1.2. OMCR for alarms/MO Dumps

1..1.3. KPI/MRR reports

• Following are listed Hardware Problems which can be Identified with the above mentioned three Inputs:

1..1.1. Faulty TRX/TRU

1..1.2. Sleeping TRX/Sleeping Cell

1..1.3. Path balance problems

1..1.4. High VSWR due to faulty feeder cable/Jumper cable

1..1.5. Sharp bending of feeder Cable

1..1.6. Improper connectors

1..1.7. BTS Cabling

1..1.8. Faulty combiner/CDU

1..1.9. BSC/Transcoder Problems

1..1.10. IDB Inconsistency

1..1.11. Slips in E1/Transmission Media

1..1.12. Clock Deviation

• Service affecting alarms on CF/TF/TRX/TX/RX are also checked which can be monitored from the OMCR.

1.2. Physical Optimization/Drive Test:

RF optimization is helpful in resolving specific coverage problems or interference problems, cell overreach, no dominant server issues, etc.

Before starting Physical Optimization/Drive test, study Reports to identify what activity has to be done to improve KPI. This will give better direction for optimization & reduce revisit on the site.

Typical thumb rule to follow while carrying out physical RF optimization for resolving coverage or interference issues -

Step 1:- Try tilting the antennas (Both Mechanical & Electrical).

Step 2:- Try changing the orientation.

Step 3:- Increase or reduce the height if tilt/reorientation does not solve the problem

Step 4:- Change the antenna type as a last resort.

• Inputs for the above activities are taken from:

1..2.1. MRR Reports

1..2.2. NCS Reports

1..2.3. Google Earth/Mapinfo

1..2.4. Drive Test Results

1..2.5. Customer Inputs

1.3. Parametric Optimization

Parametric optimization is done to bring the network performance close to desktop design.

Most of the parameters are enabled with default settings and are always kept unchanged. However there are some specific parameters which control the RF performance which can be changed on a cell or even carrier-level, to achieve specific improvements.

Flow Chart for Parametric Optimization.

Parametric Optimization Activity Details:

• Consistency Check: Some basics consistency are mentioned below

1..3.1. One Way (Single) Neighbors Defination

1..3.2. Less MAIO’s then Hopping Frequencies

1..3.3. BCCH frequency of N-CELL not included in Idle or Active list

1..3.4. Missing NCCPERM permitted values

1..3.5. External cell parameter mismatch

• Radio Feature Audit/Activation:

The lists of radio features are normally audited:

1..3.1. BTS and MS Power Control

1..3.2. Intracell Handover

1..3.3. Adaptive Configuration of Logical Channels (ACLC)

1..3.4. Antenna Hopping

1..3.5. Frequency Hopping

1..3.6. Underlaid/Overlaid subcells

1..3.7. BCCH in Overlaid subcell

1..3.8. Handover power boost

1..3.9. Hierarchical Cell Structures (HCS)

1..3.10. Cell Load Sharing (CLS)

1..3.11. SDCCH Power regulation

1..3.12. SDCCH Handover

1..3.13. Assignment to Worst Cell

1..3.14. Discontinuous transmission for Uplink and Downlink

1..3.15. Immediate Assignment on TCH

1..3.16. Flexible MAIO management

1..3.17. Idle Channel measurements (ICM)

2. Dropped Call Trouble shooting

There are mainly three statistics for Optimization

• SDCCH Drop

• TCH Drops

• Handover Statistics

Dropped Cause Analysis:

2..1. SDCCH Drops - Causes

2..1.1. Coverage

2..1.2. Congestion in TCH

2..1.3. Interference & Multipath

2..1.4. BTS performance/ Hardware issue

2..1.5. LAC Boundary

2..1.6. External Interference

2..2. TCH Drops - Causes

2..2.1. Coverage

2..2.2. Missing neighbor

2..2.3. Excessive TA

2..2.4. Interference & Multipath

2..2.5. BTS performance/Hardware Problem

2..2.6. External Interference

2..2.7. Wrong Parameter Setting

2..3. Handover Failure – Causes

2..3.1. TCH Congestion for Target Cell

2..3.2. Parameter Settings

Co-BCCH/BSIC in 2 ncells

Missing MBCCHNO

Too many MBCCHNOs

Too high hysteresis

Low output power in target cell

Hardware issue in target site

Wrong PLMN/NCCPERM

2..3.3. No Dominant Server

2..4. Solutions to Dropped Calls

2..4.1. Optimize Coverage(Physical optimization)

2..4.2. Interference Management

2..4.3. Optimize neighbors

2..4.4. Optimize handover parameters

2..4.5. Effective Frequency Hopping

2..4.6. Hardware investigation

2..4.7. In case of external interference, use of Band pass filter can solve the problem

2..4.8. Reduce Power if there is High coverage reflection due to uneven terrain or water body.