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Demonstrating the Benefits of Self-Organising Networks

3G, HSPA+, LTE Optimisation

10 - 11th March 2010

Neil Scully (Vodafone Group R&D, UK)Ljupco Jorguseski (TNO ICT, The Netherlands)

3G, HSPA+, LTE Optimisation 2010 Neil Scully (Vodafone), Ljupco Jorguseski (TNO ICT)

Outline

1. SON Introduction

2. SON activities in 3GPP and NGMN

3. Demonstrating SON benefits

a) Handover optimisation SON algorithm (SOCRATES)

b) Cell outage compensation SON algorithm (SOCRATES)

c) Energy saving SON algorithm (TNO)

4. Summary and Recommendations

2/17

Vodafone Group R&D

Building effective SON SON: Self-organising networks→ Self-configuration→ Self-optimisation→ Self-healingFocus on LTE

SON for LTE: Is it a reality?

Aligning SON with operator processes+ Use cases represent operational tasks− Alignment with practical aspects

Standardisation+ Some use cases standardised− Slow progress

Research and development+ Significant efforts− Advanced SON is complicated

Building operator trust+ Addressed by vendors− Operators still need convincing

> What is still missing?

– Real-life tests and trials

– Advanced optimisation functionality

– Integration with operator processes

3/17

Vodafone Group R&D

SON: What are the benefits?

OPEX CAPEX

Efficiency Capacity

Network quality Availability

Energy savings

Reduction of manual effort Increase or decrease?

More efficient use of engineers More efficient network

Better optimisation Reacting to failures

Switch-off unused BS

> Focus is often on OPEX benefits, but other benefits are important as well

> Benefits will increase as more SON functionality becomes available

4/17

Vodafone Group R&D

SON in 3GPP standards

> Achieving operator benefit through multi-vendor standardisation–Base stations from different vendors–SON functionality from different vendor than base station vendor

– Implies centralised solution> NGMN (Next Generation Mobile Networks Alliance, http://www.ngmn.org) has been

the driving force behind SON for LTE

2008 2009 2010

Rel. 8 Rel. 9 Rel. 10

2011

Self-configuration Self-optimisation

ANRSelf-configuration

Load balancingMobility robustness optimisation

RACH optimisationCoverage and capacity optimisation

Minimisation of drive testsEnergy savings

5/17

http://www.ngmn.org/

Vodafone Group R&D

What is being standardised? (only interfaces relevant for SON are shown)

UE

eNodeB

ElementManager

NetworkManager

Itf-S

Itf-N

X2

Focus for distributed solutions:- Mobility robustness opt. (Rel. 9)- Load balancing (Rel. 9)

eNodeB

LTE-UuUE measurements:- ANR (Rel. 8)- RACH optimisation (Rel. 9)- Minimisation of drive tests (Rel. 10)

Control and monitoring

Standardisation of PerformanceMgmt and Configuration Mgmt

6/17


Demonstrating SON benefits

Concepts and ideas for SON are usefulHowever, what will SON really do?Three example SON algorithms:

– Handover optimisation SON algorithm (SOCRATES)– Cell outage compensation SON algorithm (SOCRATES)– Energy saving SON algorithm (TNO)

SOCRATES – See http://www.fp7-socrates.eu

7/17

http://www.fp7-socrates.eu/


Handover optimisation: Introduction (Thomas Jansen, TU Braunschweig)

Problem– Non-optimal handover performance

– Handover failures– Ping-pong handovers– Call dropping

Objective– Automatic optimisation of the handover

performanceApproach

– Analyse the system behaviour– Develop handover optimisation algorithm

Control parameters– Hysteresis– Time-to-Trigger

time

HO Drop

X

Ping-pong

8/17


Handover optimisation: Analysis of system behaviour

0

2

4

6

8

10

0

0.1

0.250.5

12

50

0.2

0.4

0.6

0.8

Hysteresis [dB]

Call drops

Time-to-Trigger [s]

Cal

l dro

ppin

g ra

tio

The above figure is based on using the same parameter settings for all cellsThe developed optimisation algorithm tunes cells individually

9/17


Handover optimisation: Demonstration of results

WITHOUT SON WITH SON

100 200 300 400 500 600 700 800 900 10000

5

10

15

20

25

Time [s]

Rat

io [%

]

Handover Performance for the operating point (4, 0.48)

Handover failurePing-Pong handoverCall dropping

100 200 300 400 500 600 700 800 900 10000

1

2

3

4

5

6

7

8

Time [s]R

atio

[%]

Handover performance (Optimisation)

Handover failurePing-Pong handoverCall dropping

Performance is improved by the optimisation algorithm, relative to static parameter settings

10/17


Cell Outage Compensation: Introduction

Measurements

Goal:Mitigate coverage hole resulting from the cell(s) in outage.

SON approach: Automatic adjustment of control parameters at neighbor cells

DL control parameters: Tx Power, Antenna Tilt

UL control parameters: Po (open‐loop power control operating point) , Antenna Tilt

IMPORTANT:

1) Trade‐off between coverage improvement and quality degradation

2) UL control parameters have much higher impact (from sensitivity studies) so focus on target Rx Power (Po), Antenna Tilt

11/17

http://www.sonyericsson.com/spg.jsp?cc=se&lc=sv&ver=4000&template=pip1&zone=pp&pid=10804

http://www.sonyericsson.com/spg.jsp?cc=se&lc=sv&ver=4000&template=pip1&zone=pp&pid=10804


Cell Outage Compensation: Demonstration of results (Mehdi Amirijoo, Ericsson)

Compensating cell (blue)

Cell in outage (red)

Compensated coverage hole (grey)

10th-perc DL throughput [Mbps] (averaged over compensating cells)

10th-perc UL throughput [Mbps] (averaged over compensating cells)

Increase in number of served UEs (relative to no compensation)

Control Parameter P0

12/17


Energy Saving: IntroductionDAILY TRAFFIC LOAD VARIATIONS

0

320

640

960

1280

1600

0 3 6 9 12 15 18 21 24

HOUR OF DAY

NET

WO

RK

-WID

E TR

AFF

IC L

OA

D

48 active sites48 active sites48 active sites12 active sites12 active sites

For more details see TR 32.826 (via www.3gpp.org)!

13/17


Energy Saving: Presentation of resultsENERGY CONSUMPTION

0

0.04

0.08

0.12

0.16

0.2

0 3 6 9 12 15 18 21

HOUR OF DAY

(48,4) configuration

Energy-optimised configuration

(36,

1)

(12,

1)

(12,

1)

(12,

1)

(12,

1)

(12,

1)

(12,

1)

(12,

1)

(36,

2)

(48,

2)

(48,

3)

(48,

4)

(48,

4)

(48,

3)

(48,

3)

(48,

4)

(48,

4)

(48,

4)

(48,

4)

(48,

3)

(48,

3)

(48,

2)

(36,

2)

(36,

1)

ENERGY CONSUMPTION

0

0.04

0.08

0.12

0.16

0.2

0 3 6 9 12 15 18 21

HOUR OF DAY

(48,4) configuration

Energy-optimised configuration

(36,

1)

(12,

1)

(12,

1)

(12,

1)

(12,

1)

(12,

1)

(12,

1)

(12,

1)

(36,

2)

(48,

2)

(48,

3)

(48,

4)

(48,

4)

(48,

3)

(48,

3)

(48,

4)

(48,

4)

(48,

4)

(48,

4)

(48,

3)

(48,

3)

(48,

2)

(36,

2)

(36,

1)

Energy saving gain

(sites, # carriers) for optimized energy

consumption

Energy gain (upper bound) between 18% and 35% depending on quality target and assumptions for minimum power consumptions

14/17


Summary and recommendations

Self-Organising Network (SON) benefits for handover:– Proposed SON algorithm optimizes handover performance and sets handover operating

points per cell– The overall network performance is increased and the handover failure ratio and ping-pong

ratio drop to zero in the shown case

Self-Organising Network (SON) benefits for cell outage compensation:– Proposed SON algorithm increases coverage (number of served UEs) at a cost of quality

reduction (e.g. lower UL and DL throughputs) in the presented scenario

Self-Organising Network (SON) benefits for energy saving:– Considerable energy saving gains (up to 18% or 35%) can be achieved in areas with

redundant capacity in off-peak traffic hours as shown in the example scenario

Recommendations– Investigate corresponding OPEX savings if SON algorithm is deployed for handover

performance– Clearly define acceptable quality degradation in order to deploy SON algorithm for cell

outage compensation– Deploy energy saving SON algorithm (direct OPEX gain in lower energy costs)

15/17


Questions

16/17


Contact Details

Neil Scully (Vodafone)– [email protected]– +44 7919 994699

Ljupco Jorguseski (TNO)– [email protected]– +31 15 2857154

Mehdi Amirijoo (Ericsson)– [email protected]

Thomas Jansen (TU Braunschweig)– [email protected]

17/17

mailto:[email protected]




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