Introduction of LTE SON

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Xi Li and Liang ZhaoComNets University of Bremen

06. October 2010

Overview and Research Aspects of LTE SON

‐ ITG FG5.2.1 Workshop Stuttgart

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Outline

Main Drivers for SON in LTEIntroduction of LTE SON

Standardization Status SON Functionalities SON Architecture

Related Work and Research ProjectsMain Research Aspects of LTE SON

Radio NetworkTransport Network

Conclusions

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Outline


Standardization Status SON FunctionalitiesSON Architecture



Conclusions

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Long Term Evolution

eNB

eNBeNB

eNB

MMES-GW / P-GW

MMES-GW / P-GW

EPC (Evolved Packet Core)

E-UTRAN

S1

X2

eNB: E‐UTRAN Node BMME: Mobility Management EntityS‐GW: Serving GatewayP‐GW: PDN (Packet Data Network) Gateway

The 3GPP introduces Long Term Evolution (LTE)

high throughput

low latency

increased system capacity

Improved coverage performance

for the Next Generation Mobile Network (NGMN)

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Main Drivers for SON in LTE

Rollout of the LTE leads to rapidly expanding number of Base Stations (new sites)

parallel operation of 2G, 3G and LTE

much higher complexity in network infrastructure and network management (Operation & Maintenance)

Self‐Organizing Network (SON) aims to

configure and optimize the LTE network

automatically by Self‐Configuration

Self‐Optimization

Self‐Healing

(Source: SOCRATES Project)

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Main Objectives of SON

Network Planning

Network Planning

Network Deployment

Network Deployment

Network Optimization

Network Optimization

Network Maintenance

Network Maintenance

Self‐Configuration functions reduce CAPEX

Self‐Configuration functions reduce CAPEX

Self‐Optimization & energy saving reduces OPEX

Self‐Optimization & energy saving reduces OPEX

Self‐Optimization and Self‐Healing functions improve user experiences

Self‐Optimization and Self‐Healing functions improve user experiences

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Outline





Conclusions

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Standardization Status

3GPP has introduced SON along its standardization path as required features for LTE deployments

Release 8

eNB Self‐configuration‐ S1, X2 interface‐ Automatic Neighbor Relation‐ Automatic Physical Cell ID assignmentSelf‐optimization ‐ Basic mobility load balancing

Multi‐vendor SON interworking

Release 9

Coverage & Capacity optimizationMobility load balancingMobility robust optimizationRACH optimization…

An important source of LTE SON development is the industry forum NGMN (Next Generation Mobile Networks)

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3GPP Specifications for SON

3GPP TS 36.902, “Evolved Universal Terrestrial Radio Access Network(E‐UTRAN); Self‐Configuring and Self‐Optimizing Network (SON) UseCases and Solutions”3GPP TS 32.500, “Telecommunication management; Self‐OrganizingNetworks (SON); Concepts and requirements”3GPP TS 32.501, “Telecommunication management; Self‐Configurationof Network Elements; Concepts and Integration Reference Point (IRP) Requirements”3GPP TS 32.502, “Telecommunication management; Self‐Configurationof Network Elements Integration Reference Point (IRP); Information Service (IS)”.3GPP TS 32.511, “Telecommunication management; Automatic Neighbour Relation (ANR) management; Concepts and requirements”3GPP TS 32.690, “Telecommunication Management; InventoryManagement (IM); Requirements.”

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Functionalities of SON

Self‐ConfigurationSelf‐Configuration

‐ plug and play of new eNBs‐ automatic neighbor lists‐ self configuring RF & transport‐ ….

Self‐OptimizationSelf‐Optimization

‐ coverage & capacity opt.‐ neighbor list opt.‐ interference control‐ energy savings‐ automatic handover opt. ‐ ….

Self‐HealingSelf‐Healing

‐ automatic detection of failures‐ automatic adjustment of parameters ‐ healing schemes

Main Benefits

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SON Architecture

Source: Nomor Research: White Paper "Self‐Organizing Networks (SON) in 3GPP Long Term Evolution"

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Outline





Conclusions

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Related Work and Research Projects

The SOCRATES (Self‐Optimisation and self‐ConfiguRATion in wirelEss networkS) Project

EU 7th Framework Program

Jan. 1, 2008 – Dec. 31, 2010

Project objectivesDevelopment of methods and algorithms for self‐organization

Specification of the required measurements

Validation and demonstration of the solutions

Assessment of the operational impact

Input to 3GPP standardization and NGMN activities

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The End‐to‐end efficiency (E3) ProjectFP7 EC Integrating Project (IP)

Jan. 1, 2008 – Dec. 31, 2009

Project objectives: Design, develop, prototype and showcase solutions to

guarantee interoperability, flexibility and scalability between existing legacy and future wireless systems

manage the overall system complexity

ensure convergence across access

technologies, business domains, regulatory

domains and geographical regions

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Contributions by different equipment vendors, independents, and IT vendors

Source: from actix

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Outline





Conclusions

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Main Research Aspects of LTE SON

General considerations for all SON functionsDefine required measurements at the eNB and UE

Define the required measurement parametersDefine the measurement frequency for each parameter

Define algorithms to trigger parameter adjustmentsDetermine the thresholds to trigger parameter adjustmentsDetermine the frequency of parameter adjustments

Define rules of coordination and cooperation among different SON functions

Design SON architectureCentralized SON, or distributed SON, or hybrid SON

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Main Research Aspects of LTE SON – Radio Network

Mobility Load Balancing Optimization: to optimize cell reselection/HO parameters to cope with the unbalanced traffic load

What shall be the proper load definition?‐ radio load, transport network load, or even the processing load

‐ Split between uplink and downlink

‐ Split between different QCIs

Algorithm for load balancing ‐ The algorithm can be based on radio load, or transport network load or both of them

‐ If both radio load and transport network load are considered, which one will have higher priority?

‐ The algorithm shall also consider differentiation among QCIs

How to adjust parameters for cell reselection?

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Coverage and Capacity Optimization: to optimize the network coverage and maximize the system capacity

Solutions to detect the coverage and capacity problems automaticallybased on eNB measurements and UE reports

Design a radio planning tool to solve the problems

Interference reduction

Mobility Robust Optimization: to automatically adjust the mobility parameters

Solutions to solve the mobility problems, e.g.‐ To identify a non‐suitable cell

‐ To identify problematic settings of cell selection/reselection parameters

‐ Minimize HOs when a UE is transited from idle to active mode

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Energy Saving: to cut on operation expenses by energy savingSwitch off cells (especially needed when a larger number of Home eNBs are deployed in the network)‐ Main issue: when to active and deactivate the eNBs and how?

Adapt the transmission power‐ Adapt the transmission power while also ensuring no influence onthe coverage, handover and load balancing

Adapt the multi‐antenna schemes: some of the antennas can be switched off to save the power‐ Adapt among SIMO, MIMO, Beamforming to achieve the maximum capacity with the minimum transmission power

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Main Research Aspects of LTE SON – Transport Network

Introduction of SON for the LTE Transport NetworkTo optimize the transport resources (i.e. capacity) utilizationTo save the operation costs (for manual configurations) and bandwidth costs with optimized resource utilization

Possible Aspects:

Automatic transport QoS optimization

Automatic transport capacity allocation

Load balancing in the transport network (e.g. applying traffic engineering methods)

Transport admission and congestion control optimizations

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Main Research Aspects of LTE SON – Transport Network

Transport SON functions:Dynamic bandwidth allocation‐ Bandwidth allocation shall follow the changes in traffic load

• estimating effective bandwidth• when to trigger the bandwidth update and how

Dynamic tuning of QoS parameters‐ e.g. DiffServ model parameters, scheduler parameters, buffer management parameters per QoS class

Optimal configuration/re‐configuration of eNB connectivity with the S‐GW‐ for the Multi‐S1 scenario (i.e. one eNB connected with multiple GWs), how to configure/re‐configure in case of one S‐GW fails

Optimal load balancing ‐ e.g. to apply MPLS (Multiprotocol Label Switching) Traffic engineering method

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Outline





Conclusions

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Conclusions

SON is a promising approach to significantly reduce the network installation and operation costs, and as well can improve the user experiences

3GPP and NGMN have defined a set of LTE SON user cases and associated SON functions

Further Researches on different user cases and SON functions are needed for the LTE

LTE Radio SON

LTE Transport SON

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References

1. 3GPP TS 36.902, “Evolved Universal Terrestrial Radio Access Network (E‐UTRAN); Self‐Configuring and Self‐Optimizing Network (SON) Use Cases and Solutions”

2. 3G Americas: “The Benefits of SON in LTE”, December 2009

3. Nomor Research, White Paper: "Self‐Organizing Networks (SON) in 3GPP Long Term Evolution“

4. NEC, White Paper: "Self Organizing Network "

5. Motorola, white paper: " LTE Operations and Maintenance Strategy ‐ Using Self‐Organizing Networks to Reduce OPEX"

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Thank You for your attention!

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Introduction of LTE SON

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