rf optimization scenarios

ZAHOOR UL HAQ

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ZAHOOR UL HAQ This document is the property of ZAHOOR UL HAQ and shall not be copied or circulated without written permission.

RF Optimization Scenarios This is a brief description of the common scenarios that the RF team experience during optimization. Also described are the databases that needs checking.

Problem Parameters Physical

Dropped Calls

1. Wrong parameter settings (perform consistency checks on adjcell/adjres, hoctrl, pwrctrl, and bts objects.)

1. Wrong azimuth orientation (check site/antenna config database, also MapInfo maps)

2. Verify if default parameters matches with the current database of omc or check for mismatches between customer settings and omc settings.

2. Wrong antenna/feeder cable connections (requires site visit)

3. Analyze drive data using TEMS 3. Faulty hardware installation (see site documentation)

4. Verify the neighbor list (this falls on consistency checks)

4. Site down (check omc site alarms and status)

5. In case of interference, check BCCH database or design data

5. Analyze data, look for interference

Handover Failures

1. Wrong parameter settings (perform consistency checks on adjcell/adjres, hoctrl, pwrctrl, and bts objects.)

1. Investigate coverage plots (verify coverage holes)

2. Check LAC assignment on the release_omc or perform consistency checks on lac listings.

2. Check antenna configuration/orientation database

3. Check Pwrctrl parameters (check mismatches between default and omc settings)

3. Analyze drive test data.

Multiple Handovers

1. Verify Hoctrl parameters, Pwr Bgt Ave Period, HO_Margin etc.

1. Investigate coverage plots (verify coverage holes)

2. Check Adjcell list (verify RxLev Min Access and HO_Margin values)

2. Check antenna configuration/orientation database

3. Analyze drive test data.

Interference

1. Check BCCH listings 1. Check site reports for possible hardware problems

2. Check cluster listings and verify cells with co-channel and adjacent channel

2. Use TEMS/other tools to analyze and distinguish internal and external interference

3. Check antenna hight data base 3. Check maps and locate sites with interfering BCCHs

Wrong (Invalid) Handovers

1. Check the neighbor list and verify mutuality between adjacent cells.

1. Check antenna azimuths and tilts

Blocking

1. Check PMS statistics (daily and weekly reports)

1. Add RTs

2. Check site database and verify number of RTs

.

ZAHOOR UL HAQ

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Methods and Tools: Cluster Testing is done to fine tune the fixed network and identify coverage issues. Identifying what type of cluster methodology is used. Data Analysis and Sorting (Radio Link and Cluster Performance Test) Drive Test Data indicates the status of the cluster before, and after, the addition of sites. Also indicates coverage issues. Customer Complaints (Trouble Tickets) are collected from the Customer Service Department and RF related issues are sent to the Network Planning department. The complaints are sorted into clusters and are given to the RF engineers to work on. PMS (Performance Measurement Sub-system) monitors network performance and creates reports that are then analyzed by the RF engineers during the performance testing. OMC Data is accessed and used to assess current network status information Cluster Drive Testing involves: 1. Defining Drive Routes 2. Drive Test Scheduling: Night Drive (off-peak time testing) Day Drive (peak-time testing) 3. Data Analysis and Recommendations

Analysis concentrates on coverage and quality issues. The drive test data analyzed is RXLevel, RXQual, MSTxPWR, and intra-Cluster connectivity.

4. Fine Tuning: Changes in parameters after analysis have been made. 5. Determining RF Coverage holes 6. Post- Processing of Drive Test Data using MapInfo and GIMS 7. Analysis using TEMS 8. Site visits if necessary 9. Printing and analyzing drive test plots for analysis and presentation Main Issues of Concern: Dropped calls Call setup failures Poor coverage Handover Failures Transmission and Synchronization Interference Blocking, etc. Actions: Workorders are produced for implementation of new services, and changes to the existing networks.

ZAHOOR UL HAQ

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Drive Test and Analysis Tools: MapInfo – desktop/pc mapping software GIMS – TEMS post processing software in MapInfo Ericsson TEMS mobile phone (1 or 2) GPS and external antennas Notebook computer and accessories Switch Terminal/AUI/GUI – real time switch terminal necessary for retrieving current network status information, cell parameters, BSS parameters, etc. Initial Optimization The purpose is to verify the basic performance of the radio-network and identify severe RF problems and possible hardware problems. Responsibilities of the RF engineering group: Preparation phase:

Reviewing frequency plan Preparing and checking of RF related OSS BSS data Handover performance Handover order Inter BCE Handover Inter MSC handovers Coverage Service quality

In contrast, ongoing RF optimization can cover issues such as resolving the main reasons of the degradation of the radio-network performance, which are the following:

Congestion Oscillating Handovers Actual network reconfiguration Interference caused by increasing traffic

ZAHOOR UL HAQ

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A summary of Radio Performance Test and RF Optimization Tasks:

Task Radio Performance Test RF Optimization

Call setup possibility

Checking the feasibility(possibility) of setting up MS originated calls and MS terminated calls

During RF optimization it is possible to keep track of call setup performance, because sufficient number of network statistics data and drive test data will be available.

Handover performance

Verification of proper handover function for each defined neighbor relationships

- identifying handover areas between all neighboring site(s) - identify and prioritize all abnormal handovers - adjustments for the elimination of oscillating handovers - the handover areas are identified on a map for future optimization

Handover order check correct handover sequence

Traffic distribution

Shifting or reducing the traffic from congested site(s) to its neighboring sites and optimize traffic flow in the network, handle hot-spot areas

Frequency plan adjustment

When new site is going to be integrated into network the initial frequency plan will be reviewed and readjusted if necessary

Due to the sufficient amount of network statistics data and drive test data more efficient frequency will be possible to be implemented and achieve higher capacity of the network

Coverage

During each site testing it will be possible to check correct per cell coverage distribution and identify- resolve general service degrading coverage problems

Due to the more extensive drive tests detailed mapping of the coverage will be available. In this case collected data will be sufficient for fine tune of antenna configuration in order to achieve evenly distributed coverage along clusters of sites

Service Quality

Any potential or identified interference issues, during the site tests, are analyzed and minimized

Increasing traffic and capacity up- grades of the network will result in new interference issues that can be identified and resolved only by regular monitoring of the network from network statistics and drive test Data inputs.

By:

ZAHOOR UL HAQ RF Engineer HUAWEI TECHNOLOGIES Ltd.

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