3G Voice Opt

8/11/2019 3G Voice Opt

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Lucent Technologies ProprietaryNo.1

3G1x Voice RF Optim izat ion Procedures

Devesh PatelCDMA RF Opt imizat ion & App l icat ions Group

[email protected]

(973) 386-6280

Sept 11, 2001
mailto:[email protected]:[email protected]


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Learning Objectives

Upon completion of this presentation, the participant will have anunderstanding of :

Drive test based methods and procedures needed to optimize a 3G1x Voice network

RF Tuning Parameters

Steps involved in optimizing a new 3G1x Voice network

Drive test based techniques Data collection tools and metrics

Various Optimization phases/tests

Overview of Optimization problems

Various options for migrating from 2G to 3G voice

Associated optimization tools and methods

Various intra/inter-generation handoff types3G to 2G, 3G to 3G, 2G to 2G handoffs

Overview of optimization considerations


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Outline

RF Optimizationdefinition and objectives


3G1x Voice Cold startRF Optimization procedures

Drive test based

Data collection tools and metrics


Overview of Optimization problems

Overview of drive test alternatives

Migrating from a 2G network to 3G voicevarious options

Associated optimization tools and methods

Various intra/inter-generation handoff types

3G-to-2G handoffs3G-to-3G or 2G-to-2G handoffs

Optimization considerations


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RF Optimization - Definition

Defined as the process of fine-tuning all aspects of air-interfaceperformance in a network.

Main objective is to allow acceptable voice quality

Several optimization approaches:

Drive test mobile data based

Drive test Pilot scanner based

Prediction modeling / SM troubleshooting based

Presentation focuses on drive test data based techniques

End goal is to prepare a network for commercial operation

Some fine-tuning during commercial phase


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RF Optimization for 3G1x Voice - Objectives

Fundamental goals of RF Optimization for 3G1x Voice remain the same as 2G Acceptable paging, access, forward/reverse voice coverage

Measured based on FER, Ec/Io, mobile transmit power, mobile receive power

By ensuring good coverage dropped calls will automatically be minimized

Minimal number of dropped calls, missed pages, and failed accesses

Measured from dropped call and access tests

Fine tune performance of paging and access channels as necessary

Acceptable fractions of soft/softer handoff activity

Measured from overall handoff statistics with and without traffic loading

Adjusted sparingly with soft/softer handoff threshold changes

Attempt to keep consistent handoff thresholds throughout the network

IS 95B soft handoff thresholds require further study

Acceptable performance for semi-soft and hard handoffs

Measured from drop call statistics in these handoff zones


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RF Tuning Parameters - Primary

Primary Optimization Parameters: Coarse control of RF environment

BCR/CBR Attenuation (transmit power of each sector)

Antenna Configurations (azimuth, downtilt angle, height, pattern type)

Neighbor List Entries and Priorities (FCI and CDHNL forms)

Neighbor Set Search Window size

CDMA Semi-Soft and Hard Handoff Thresholds (F2->F1, F1->F1) (including 2G->2G,3G->3G,3G->2G)


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RF Tuning Parameters - Secondary

Secondary Optimization Parameters: Fine control of local performanceSoft Handoff Thresholds (IS 95A or IS95B)

Active Set Search Window Size

Cell Site Search Window Size

Pilot, Page, Sync, Quick Paging, Traffic Channel Digital Gain Settings

Access probe nomand initpower levels

Sector Size and Access Preamble Size

TCA bias

Inter-technology load preference deltas

Allow 3G1x sharing

Note:2G and 3G load preference deltasandAllow 3G1x sharingare new in 17.03.

They only apply for systems with mix 2G and 3G channel cards; not for a pure 2G or 3Gsystem. Their use is more in the commercial phase to adjust 2G and 3G traffic distribution

across 2G/3G carriers as 3G usage grows.


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RF Tuning ParametersFixed Parameters

Fixed Parameters: NOT Changed During RF Optimization Forward and Reverse Power Control Thresholds

Forward and Reverse Overload Control Parameters

Remaining Set Search Window Size

Reverse Pilot Fraction


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Optimization procedures3G1x Voice Cold Start


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3G1x Voice Cold Start -

RF Optimization Options

3G1x Voice Cold start defined as a new 3G1x Voice network

Basic options for 2G optimization apply to 3G Voice

drive test using Full rate Markov call in Radio Configuration 3 (RC3) mode

iterative approach for tuning key parameters

drive test using integrated Markov call and Pilot scanner approach

adds drive data independent of system parameters being optimized facilitates optimization of forward link coverage via software based predictive

analysis

zero drive optimization

predictive tools (Ocelot) used to provide initial solution

SM data, infrastructure capabilities, analysis tools used to further refine

performance based upon commercial data

Some amount of drive testing possible during commercial phase to trouble

shoot problem areas


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RF Optimization Tools for Drive

Testing

Mobile Data Collection Test SetupProvides efficient/reliable collection of mobile data

Similar test setup for drive test optimization can be used for 3G Voice

CAIT based

Key components 3G phone (MSM5000 based Qualcomm test phone)

CAIT

GPS unit

Laptop with PCMCIA dual socket I/O card

Isolation box

Attenuator box to simulate in-vehicle penetration and reverse link loading

Magmount antenna


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RF Optimization Tools for Drive

Testing cont .

RF Call Traceallows certain performance data to be collected at cell site

Suite of Data Analysis Tools

LDAT 3G

Provides analysis of mobile and RFCT data

Key outputs include- Forward and Reverse Frame Error Rates

- Pilot Ec/IoMax FCH finger, Aggregate

- Mobile Receive and Transmit Power

- Forward link traffic channel power (power relative to Pilot, not dgu as in 2G;

available starting 17.1)

- Number of Pilots above threshold- Alert/orig/term/build capabilities (3gtool)


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Pre-test Preparation

Perform Sector Verification Test

Initial drive test to assure all sectors are operational, antennas properly oriented, cabling

correctly installed, call processing and handoffs functional, translations properly set

identify and correct installation and database problems at an early stage (coaxial

cable/connector failures, misoriented antennas, erroneous translations)

Calibrate Cell Site Transmit Power

Manually adjust power for calibrated output levels at antenna interfaces

Initial transmit power settings to achieve baseline ERPs (Effective Radiated Power) for all

sectors in cluster

Configure System Parameters Based on Recommended Settings

Tests/analyses are continuously executed to ensure that recommended parameters

provide optimal starting point

Application Notes provide recommended translation parameters


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RF Optimization Phases

RF Optimization is performed in two phases: cluster testing and system wide

testing

Cluster Testing

Performed on a geographical grouping of cells (approx 20 cells)

Provides initial pass at optimization

Stages of cluster optimization include

Unloaded Coverage Test Loaded Coverage Test

Often requires iterative passes

Initially focus on coarse tuning

- adjust primary optimization parameters

Follow up with finer tuning

- iterate primary parameter adjustments as necessary and additionally makesecondary parameter adjustments

Problems that can not be resolved in a reasonable amount of time are often

deferred until System Wide Testing


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RF Optimization Phases cont .

System Wide Testingmore detailed tuning phase to address specific problems identified during cluster testing

perform loaded coverage test on major roadways

also isolate problem areas in cluster overlap regions

characterize overall system performance

comprehensive statistics compiled to assess overall system performance

Additional tests may be performed to further characterize system performance- dropped call tests

- origination and termination tests


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Unloaded Coverage Test

Drive test using single test phone with Full Rate Markov call in RC3 mode

Besides the test call, only Pilot, Page, QPCH and Sync channels

Analyze Best Server Ec/Io and Number of Pilots Above Threshold

Identify Marginal Performance Areas

Weak Coverage (Best Server Pilot Ec/Io< -12 dB)

Multiple Pilots (Number of Pilots with Ec/Io greater than -15 >= 4)

Examine Pilot Ec/Io Per Sector to identify coverage area of each sector

Specialized analysis tools indicate neighbor list omissions, weak coverage areas,

and multiple Pilot regions

Analysis of dropped calls observed during drive tests

Primary Parameter Optimization

Coarse adjustments to control RF environment and fix neighbor lists

Secondary Parameter Optimization

Fine adjustments to improve performance in local areas (mainly handoff thresholds)


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Drive test and iteratively optimize any additional trouble spots using primary and

secondary tuning parameters Drive same routes as the unloaded coverage test under loaded conditions

Use simulated load during the drive test

Drive test using single test phone

Full Rate Markov call in RC3 mode

Use RF Call Trace to log Reverse FER and Forward link traffic power

Perform any additional tests necessary to assess performance against cluster exittargets

Frame error rate test, call hold test, origination test, and termination test

Final Performance Validation test (cluster exit criteria)

Average FFER, average RFER, Dropped Call Probability, Origination Success Probability,

Termination Success Probability

Loaded Coverage Test


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Loaded Coverage Test cont .

Simulated Forward link loading provided with Orthogonal Channel Noise Source (OCNS)

Simulates traffic by turning on unused Channel Elements (CEs) under software control

Allows for variable loading on per-sector basis

Loading levels per contact

3G loading OCNS values should be similar to that for 2G

Simulated reverse link loading provided with attenuator in the reverse path

Place calibrated attenuator in-line between portable and roof mount antenna

Circulator(s) used to separate forward and reverse paths so attenuator only effects reverse

link

Simulates average, uniform traffic loading across all sectors on reverse link

Attenuation value per contract

Lower 3G mobile transmit power relative to 2G allows larger attenuation value

Allows increasing mobile transmit attenuation by 2dB


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Typical Optimization Problems

Neighbor List Omission

High FER or call drop in area characterized by strong pilot Ec/Io

Inadequate Mobile/cell site Search Window Size

High FER or call drop in area characterized by strong pilot Ec/Io

Forward Link Coverage problem

Characterized by Low Ec/Io from best server, low mobile receive power, high transmit

digital gain, and high forward FER

Excessive Internal-Interference on Forward Link

Low Ec/Io from best server, adequate mobile receive power, high transmit digital gain,

and high forward FER

Often there are four or more pilots present with nearly equal strengths and the total

signal level causes Ec/Io of all servers to be reduced

Around-the-Corner Problem

Mobile sees strong interference, mobile does not handoff to strong pilot soon enough,may drop the call


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Neighbor List Formation Guidelines

Keep neighbor lists as small as possible

Neighbor lists from Active pilots combined using 3 criteria

number of times a Neighbor is repeated on Active pilots Neighbor Lists

rank of the Active set pilot, based on strength or distance

strength is recommended

highest priority from Active pilots lists

Combined neighbors sorted, top 20 sent to mobile


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Commercial Monitoring

At conclusion of system-wide testing, the system is ready for live traffic

Optimization is an on-going process for a commercial network

additional tuning may be needed to accommodate uneven traffic patterns

new cell sites added to system

additional CDMA carriers added to system

design enhancements may lead to additional tuning

Various data sources to isolate problem areas.

Service Measurements

ROP

Undeclared neighbor list

Handoff Matrix

SPAT aids analysis by integrating data from above sources

Drive testing as needed


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Commercial Monitoring cont.

Typical problems:High dropped call/access performance

unacceptably high soft handoff usage

poor call performance due to bad hardware

unequal loading across carriers (esp. on inter-frequency handoff sectors)

inter-technology load preference deltas


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Pilot Scanner Based Approach

Viper is a pilot scanner developed by Agilent for optimizing and troubleshootingCDMA networks

Agilent pilot scanner available for US cellular frequencies and Korean PCS band

A pilot scanner provides pilot Ec/Io measurement for all pilots at each measurementpoint

data can be collected independent of system parameters

complete set of data is provided

Accurate and complete pilot survey data allows for comprehensive characterizationof coverage

allows for utilizing advanced tools to take advantage of complete data

improve speed and quality of optimization

Allows iterations to be performed in software rather than repeated drive testing

predict change in pilot coverage due to: change in BCR, antenna adjustment, forwardlink loading, or cell site additions

recommend FCI neighbor listsrecommend search window settings

Utilize Mongoose functionality of LDAT 2G for iterative prediction


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Pilot Scanner Issues

Basing optimization on single set of data

predicting changes in pilot coverage requires complete and accurate set of datainaccurate or incomplete data will propagate through all software iterations

Scanner data provides only forward link coverage data

Agilent tool set allows simultaneous collection of mobile data

Mobile provides reverse link data, performance data, etc.

help identify trouble spots

provide reverse link information

provide data for exit criteria testing

Use of mobile and pilot scanner data together complement each other

Rate of pilot scanning is important

Results should characterize long term channel conditions

Viper samples channels approximately once per second

For 3G, continue to utilize 2G Pilot scanner kit

Will also need a separate CAIT based 3G phone kit for exit criteria testing


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Zero Drive Test Optimization

Propagation-predictive models are combined with traffic load information tooptimize

Network Coverage

Network Capacity

Initial optimization is done with respect to a user-defined set of network parameters

in OCELOT

Cell-power levels, Antenna tilts, heights, orientation, azimuth.

Other parameters that control link or cell performance,

i.e. handoff thresholds

Subsequent fine-tuning using switch-based performance tools and friendly user

traffic

minimizes drive test cost

thorough and more accurate view of traffic compared to fixed drove route

Primary tool is System Performance Analysis Tool (SPAT)


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Coverage and Capacity Tradeoff Example

Network coverage:

The fraction of voice or data traffic that can receive service with link quality adequate todeliver desired service.

Coverage-limiting factors: Noise and interference.

Network capacity:

Amount of voice or data traffic the network can handle at a user-defined overallnetwork blocking rate.

High Capacity- Low Coverage Reduced Capacity- High Coverage

Cells have equal traffic load

Large interference areaCell-traffic unbalanced

Small interference areasTilt

Example:5-Sector Scenario


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Coverage and Capacity Trade-off Space

Optimize for all trade-offs

between network coverage and

network capacity

Tradeoff space

Every point in tradeoff space

corresponds to one network

configuration.

Its position represents the

network performance of that

configuration.

The best configurations

found form the Tradeoff

curve.

Tradeoff Curve:

Optimum Configuration

Initial

configuration

Tradeoff Space

Maximum Coverage

Configuration

Maximum Capacity

ConfigurationKnee of

Tradeoff Curve

0.80 0.85 0.900.8

0.9

1.0

1.1

1.2

Optimized

InitialNetworkCapacity

Network Coverage


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2G to 3G1x Voice migration

Scenarios and Optimization steps


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2G to 3G Migration

3G services can be gradually phased in on existing 2G deploymentsStart with

2G and 3G on the same carrier, or

introduce 3G on a separate carrier

Equip more 3G resources as 3G usage increases

Cell site upgrade to 3Guse of CCU-1x/ECU-1x channel card

RF optimization/validation tools &


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RF optimization/validation tools &

Metrics

RF tool kit similar to that for optimization of a 3G1x voice Cold start However, requires two handsets

One 2G phone and one 3G phone

Configuration similar to the dual mobile kit used for 2G multi-carrier optimization

RFCTtrace two phones (2G and 3G)

Loading

OCNS loading will be similar to that for 2G 3G phone could use additional 2dB attenuation compared to the 2G kit

Analysis Tools LDAT3G

3gtool

Continue to use LDAT and alert/orig/term tools for 2G phone until LDAT3G is fully compatible

Metrics

Similar to 3G1x Voice cold start or a 2G network

3G1x Voice should perform equally or better than 2G

RF Optimization Integrating 3G into 2G


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RF Optimization - Integrating 3G into 2G

Network

Integrating 3G1x into existing 2G network on the same carrier

Integrating 3G1x voice into existing 2G network should not require re-optimizationin core 3G area

primary goals of optimization are the same

optimization parameters are the same

tool set for drive optimization for 3G1x analogous to 2G

3G1x voice coverage should be as good or better than2G

If 3G1x is not deployed throughout the network then 3G1x to 2G handoff borders

require optimization(discussed later)

Can utilize SM/ROP data as 3G mobiles make commercial usage

isolate problem areas esp. at 3G-to-2G borders

approach allows getting to commercial stage quicker

Distribute 2G/3G traffic to carriers with respective hardware using 2G and 3G loadpreference deltas and Allow 3G1x sharing parameters

- Adjust with growth in 3G subscriber traffic

- Parameters/recommendations discussed in a separate ppt. for RF App. Notes

RF Optimization Integrating 3G into 2G


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RF Optimization - Integrating 3G into 2G

Network cont .

Several migration options possible

Coexist with 2G, or on a separate carrier

Ubiquitous, or concentrated deployments

Four potential scenarios illustrated on following slides

Optimization needs are scenario dependent


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2G to 3G MigrationScenario 1

F1: 2G

F2: 2G

F1: 2G/3G

F2: 2G

Highlights

Deploy 3G voice capability on same carrier (F1) throughout network

No 3G/2G handoff boundaries (unless in overload/resource shortage)

No inter-frequency handoff boundaries (unless in overload/resource shortage)

Requires 3G CCUs on F1

Optimization

No need for RF optimization

No 3G-to-2G handoffs or inter-frequency handoffs to optimize

Customer may require validation

Simultaneous 2G/3G phone calls on the same carrier (F1)use a RF kit with two phones (2G & 3G)

System wide loaded drive should suffice (commercial traffic loading should suffice)

Introduce 3G on an existing carrier


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HighlightsAdds 3G Voice capability on an existing carrier in some parts of the network

3G/2G handoff boundaries

No inter-frequency handoff boundaries (unless in overload/resource shortage)

Requires 3G CCUs on F1 in some parts of the network

Optimization

3G-to-2G handoff boundaries to optimize (details later)

No optimization in the core 3G service areapotential validation similar to scenario 1 - perform it after 3G-to-2G handoff optimization

Partial 3G addition the same carrier

F1: 2G

F2: 2G

F1:

2G/3G

F2: 2G

F1: 2G

F2: 2G


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HighlightsAdds 3G Voice capability on a new carrier in some parts of the network

3G-to-2G inter-frequency handoff boundaries

Requires 3G CCUs on F3 in some parts of the network

Optimization

Optimization in the core 3G service area

Similar to scenario 2

Test Carrier capability (exclusive mode) can be used since separate carrier3G-to-2G inter-frequency handoff boundaries to optimize

Methods similar to 2G-to-2G multicarrier handoffs [2]CIFHOTI and CMPIFHO recommended

Partial 3G addition on a new carrier

F1: 2G

F2: 2G

F1: 2G

F2: 2G

F3: 3G

F1: 2G

F2: 2G


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Various inter/intra generation handoff types3G-> 2G

2G->2G

3G->3G


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3G to 2G Handoffs Overview

As 3G is integrated into network it is desirable to support handoffs between

technologies

Primary Objectives

Provide reliable and efficient handoffs of Voice calls at 3G to 2G borders

support localized 3G implementation

support 3G to 2G interfrequency and same frequency handoffs at borders

Provide reliable method of interfrequency handoff if resource blocking occurs hand off to 3G or to 2G

For ubiquitous 2G/3G deployments, software prefers same technology handoffs (2G to

2G, 3G to 3G) at frequency borders or resource overflows


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Some Simple Scenarios

F1, 3G/2G

F1, 2G only

F1, F2

F1Only F1= 2G

F2 = 3G

F1,F2

both carriers = 2G/3G

Scenario 1 - Ubiquitous 3G/2G Coverage Scenario 2 - 3G/2G Same Frequency Border

Scenario 3 - 3G/2G Interfrequency Border

3G to 2G Same carrier Handoff


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3G to 2G Same carrier Handoff

Capabilities

Same frequency3G to 2G Handoff

3G call attempting to soft handoff to 2G only cell will be directed to 2G on thesame carrier

- will handoff directly into multiple way handoff

- triggered automatically; no translations required

Mobile must support 3G rate set on 2G

If the candidate 2Gonly cell on the current carrier is loaded/resource limited,

transition the call to 2G on another unblocking carrier

Trigger Criteria:

A 2G-only candidate set Pilot triggers 3G to 2G handoff

- If aggregate Active set Pilot Ec/Io is > -10 dB

Then the candidate 2G only Pilot Ec/Io must be equal/stronger than the

strongest Active set Pilot,

- Else the candidate pilot must exceed Tadd

3G-to-2G Same carrier Handoff example


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p

(npar5108 output)

A 3G-to-2G handoff event can be spotted from npar output of CAIT logs (example below)

General Handoff Direction message includes p_rev X, where X


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Optimization

The aggregate Pilot Ec/Io qualifier of > -10 extends the 3G call until mobile is

relatively close to a 2G only cellAllows maximizing 3G coverage

However, delaying the handoff transition may also result in a failed handoff and hence,

dropped call

Attempt optimization to improve in the problem areas

3G to 2G border test cluster/route selection

Should include area comprised of last tier of 3G cells as well as first tier of 2G onlycells

Similar to inter-frequency border area selection

Pick drive routes to traverse from 3G towards 2G-only coverage

Drive Procedure

Drive with 3G and 2G call on the same carrier

Testing during night time under unloaded and loaded conditions Same load as for the core 2G or 3G Voice area optimization

Investigate where 3G calls drop but 2G does not

3G-to-2G Same carrier Handoff


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Optimization cont.

Optimization/Troubleshooting

Most important reason for call drop should be rapidly rising Pilot

Adjust coverage to move handoff trigger area to alleviate the problem

Testing during night time under unloaded and loaded conditions

Same load as for the core 2G or 3G Voice area optimization

Other problem may be with 3G call handing to 2G too early. Possible source will be a 2G-only Pilot overshooting into 3G core area

- Assuming there are no 3G resource limitations

Attempt to reduce the 2G-only overshoot

- Otherwise 3G coverage/capacity will be sacrificed along the border

3G to 2G Inter-frequency Handoff


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Capabilities

Inter-frequency3G to 2G handoff

All currently supported inter-frequency handoff techniques apply. Includes:

- Pilot Assisted Handoff (Tcomp triggered or Tadd triggered)

- Directed Handoffs (cdhnland cdhflforms)

o Interfrequency Handoff Improvements (FID3006.1 or FID3006.2)

o Non-Pilot Assisted Handdown/Blind Handover

Optimization

Methods are similar to that for 2G to 2G multi-carrier handoffs [2]

3G to 2G Handoffs- Soft Handoff Blocking


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g

Scenarios

If 3G soft handoff is blocked then call will maintain 3G if possible

If another carrier has 3G resources available the mobile will IFHO to carrier using

standard pilot assisted techniques IFHO techniques

handoff to multiple way if CPMIFHO is enabled

If 3G resources are unavailable will go to 2G mode if mobile is rate capable

if applicable will attempt to stay on same carrier

handoff to alternate carrier directly into multiple way handoff (regardless of

CMPIFHO status)


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3G-3G or 2G-2G inter-frequency handoffs

Refers to same technology (3G to 3G or 2G to 2G) handoffs across different

carriers

Similar to inter-frequency handoff techniques in 2G

In a network with mixed 2G/3G service, same technology inter-handoffs favored

E.g., where 3G footprint on a specific carrier ends, software will attempt to

transition the call to a common 3G carrier, if available.

If not, transition the call to 2G

All 2G supported techniques available

Pilot Assisted Handoff (Tcomp triggered or Tadd triggered)

Directed Handoffs

- Interfrequency Handoff Improvements (FID3006.1 or FID3006.2)

- Non-Pilot Assisted Handdown/Blind Handover Optimization

Same as for existing 2G to 2G multi-carrier handoffs [2]

I t l P i t f C t t / R f


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Internal Points of Contact / References

Who to call for support/questionsDevesh Patel [email protected] (973) 386-6280

Anu Sandhu [email protected] (973) 386-3166

Murat Berin [email protected] (973) 884-5480

References

[1] 3G-1x Voice RF Optimization GuidelinesRFEC (DRAFT)

http://rfec.wh.lucent.com/html/cdma/rf_amp_docs.htm

[2] Multi-carrier RF Optimization Guidelines for PCS and Cellular CDMA

Systems Version 5.0

http://rfec.wh.lucent.com/html/cdma/rf_amp_docs.htm

S i S
mailto:[email protected]:[email protected]:[email protected]://rfec.wh.lucent.com/html/cdma/rf_amp_docs.htmhttp://rfec.wh.lucent.com/html/cdma/rf_amp_docs.htmhttp://rfec.wh.lucent.com/html/cdma/rf_amp_docs.htmhttp://rfec.wh.lucent.com/html/cdma/rf_amp_docs.htmmailto:[email protected]:[email protected]:[email protected]


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Session Summary

RF Optimizationdefinition and objectives


3G1x Voice Cold startRF Optimization procedures

Drive test based

Data collection tools and metrics


Overview of Optimization problemsOverview of drive test alternatives

Migrating from a 2G network to 3G voicevarious options

Associated optimization methods and tools

Various intra/inter-generation handoff types

3G-to-2G handoffs

3G-to-3G or 2G-to-2G handoffs

Optimization considerations

3G Voice Opt

Documents