3G Handover Optimization

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3G Handover parameter optimizationOctober 2013

1 © Nokia Siemens Networks 2011

For internal use

Unique document identifier (ID) / Version number / Life cycle status

Dept. / Author / Date


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Motivation to pay attention to 3G HO parameters

1) Need to make the current neighbors to work better• When optimizing 3G neighbors very often the conclusion after identified the

poor neighbors is to keep them but to optimize the behavior

• Increase the amount of handovers

• Improve handover performance• By optimizing radio conditions

• Or by optimizing handover parameter settings

2 Need to ensure data call performance also through cell-reselection


For internal use


• Different re-selection criteria are applied for different types of cells andhandover directions

3) Need to managing the traffic steering in overlapping network layers• In order to maximize the utilization of network resources or use them

according to operator strategy, there is a need to control what traffic is servedin each layer and how

• Need to optimize UE handling in idle and connected mode

• Need to optimize handover triggering criteria



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Full process for handover optimization available

NetAct Optimizer current release supports WCDMA HO optimization process

• Actual network situation can be easily analyzed in one view• Overlapping cell layers and neighbors, from different vendors

• Performance of cells and neighbors can be viewed or

automatically analyzed• KPI analysis Traffic in classes, HO statistics

• Cell pair level signal overlap analysis

• Geo-KPI analysis for area troubleshooting


For internal use


• Current HO settings• Neighbor relations can be optimized

• Creation, deletion, list length optimizationfor all neighbor types based onmeasurements

• Radio conditions can be optimized• Signal overlap situation can be

improved to enable successful handovers

• Handover parameters can be manually modified



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Automated WCDMA Handover optimization

An optimization algorithm added in NetAct Optimizer to• Identify the WCDMA intra-frequency and inter-frequency neighbors

where handover performance is not on target level

• Clarify the root cause for the poor handover performance

• Propose better parameter values for handover triggeringAlgorithm considers both speech and data calls separately

Visual methods enhanced to evaluate the


For internal use


Optimizer functionality is controlled via SON Operations Managerto enable highly automated process

• Triggering criteria for algorithm execution can be set• Ability to control the execution order of the alternative algorithm

• E.g. whether poorly working neighbors are deleted or if they are optimizer



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Controlled Traffic Steeringin Heterogeneous NetworksOctober 2013


For internal use




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Operator strategies/targets with multipleoverlapping radio networksMost of the operators have radio network from multiple vendors and multiple

technologies covering the same area

• GSM 900 and GSM1800

• WCDMA several frequencies

• LTE spots or seamless coverage• Large umbrella cells, small micro cells,

even pico cells and femto cells…


For internal use


Via the overlapping coverage they are usually targeting to• Seamless coverage

• Adequate capacity in general

• Adequate capacity for specific value added traffic (services, subscribers)

Operator strategies in investing on all the layers and using these are very different


In order to use the investment according to strategy it must be possible tomonitor and control on how the traffic is moved across the network layers


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Traffic Steering layers

Management of Traffic Steering

Service Mgmt

Resource Mgmt

Service Mgmt

• The service and subscriber dimension,QoE

• Control from the service layer, e.g.

policies, subscriptions, …

Resource Mgmt

• Monitor NW QoS, usage and capacity

• Control the confi uration of network

M oni t or

C on t r ol

O p t i mi


For internal use



3G

LTE

2Gmacro

Small cells

Network functionalities

• Steering of traffic to the desired layers

• Based on e.g. priorities, services, UE,coverage and load

• Requires control

• Distributed functions and intelligence

transport

traffic steering functionalities for desiredoutcome, e.g. priorities

• Optimize the relevant parameters, e.g.triggering thresholds, …

utomat on

z e

radio core


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Traffic Steering in heterogeneous networks

•Traffic steering targets in load balancing and

improving the subscriber performance byforwarding the traffic efficiently between thenetwork layers based on availableinformation

− UE / network capability

− Requested service, QoS/QoE KPIs, QoSdifferentiation

− Cell load− Power consumption in UE and BTS− UE measurements− UE s eed and mobilit


For internal use


Traffic steering in idle mode

• Direct idle devices to the preferred active state uselayer to avoid unnecessary handovers and ping-pong for improved network service quality

• Layer selection is steered by adjusting measurementrules, cell reselection priorities, thresholds andoffsets

• Criteria for layer selection: device capability andpenetration, UE velocity and cell load

Traffic steering in connected mode

• Pushing the active calls to the appropriate layeraccording the session characteristics andnetwork capability

• Layer change is usually based on handover andcell reselection criteria

• Criteria for layer selection: used services, UEvelocity, UE and network capabilities matching,load in source and target cells, signal strength


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Traffic Management functionality for Optimizer

Traffic management starts by seamless analysis of the network and trafficconditions – All radio technologies and inter-system traffic

– Traffic class analysis in each geographical area

– All relevant domains like radio and transport

Traffic management functionality is handled in two levels

1. Target behavior setting by optimizing idle mode parameters


For internal use


– To ensure the right types of calls are activated in the right network layer – User controlled adjustment for the cell selection criteria

– Algorithm analyses the network based on statistics and according the given controlcriteria sets the optimal parameters

2. Traffic management principles for active calls – To help network elements to execute traffic steering according to operator strategy

– Adjustments for Handover or cell reselection criteria are made based on networkperformance and given control criteria


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Traffic Management capabilities in Optimizer today

NetAct Optimizer in OSS5.3 releases onwards provides a good base line formanaging the traffic steering in multi-radio network

Complete view to all overlapping network layers

• Optimizer provides one view to see 2G,3G and LTE network of any vendor• Network settings like neighbors or performance like traffic can be presented in the

common view


For internal use


Means to analyze the capacity utilization from end to end• Optimizer provides automated functionality to check the capacity bottlenecks in

the network now or near future

• In radio and transmission domain

Means to adjust the traffic steering related parameters manually

• In the current Optimizer the changes to parameters can be done manually andprovisioned automatically



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Balancing traffic load between GSM & WCDMA in acapital areaThe problem of one of the leading operators in Europe was to balance the load

between GSM and WCDMA

NetAct Optimizer was used to analyze thenetwork behavior in both layers

• Problematic cells were identified usingthe data provided in Optimizer• neighbors, handover attempts, traffic in cells and handovers

• Measurement based signal overlap and interference


For internal use


• signal strength and quality measurements from UEs,

propagation delay, timing advance

• Identification and elimination of theovershooting signals executed

”We met the target.The network was clearly stabilized andforced handover amount decreased.Optimizer provides unique visibility

and easy analysis of WCDMA behavior”

Analysis of an interferer:RSCP Threshold > -95, Distance >1kmprioritized with number of interference

samplesProblematic cells are ones with mostmeasured interference pairs

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3G Handover Optimization