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FP7 SOCRATES
FP7 SOCRATES
Hans van den Berg (TNO, NL)
Ljupco Jorguseski (TNO, NL)
Neil Scully (Vodafone, UK)
Informa SON Conference, London, 30 Nov – 1 Dec 2010
WWW.FP7-SOCRATES.EU
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
1. SOCRATES Overview (15 min)
a) Background, approach, use cases
b) Main results
2. SON Concepts in SOCRATES (15 min)
Q&A (5 min)
3. SON Simulation Demo’s (30 min)
Q&A (10 min)
Outline
2/17
Hans
Neil
Ljupco
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
� SOCRATES
– Self-Optimisation and self-ConfiguRATion in wirelEss networkS
� Project period
– 3-year duration: From 01/01/2008 until 31/12/2010
� Effort
– Number of person months: 378
– Total project costs: € 4,980,433
� Consortium
FP7 SOCRATES
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
� Self-organisation in wireless networks
– Self-configuration
– e.g. ‘plug-and-play’ of new base
stations
– Self-optimisation
– measurements, processing,
parameter adjustment, …
– continuous loop
– Self-healing
– failure detection
– automatic minimisation of
coverage/capacity loss
� Focus on 3GPP LTE (E-UTRAN)
� Evolutionary approach
Measurements(Gathering and processing)
Self-optimisation
Setting
parameters
Self-healing
Self-configuration
continuousloop
triggered by incidental
events
Measurements(Gathering and processing)
Self-optimisation
Setting
parameters
Self-healing
Self-configuration
continuousloop
triggered by incidental
events
FP7 SOCRATES: KEY ISSUES
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
SELF-ORGANISATION: EXPECTED GAINS (1/2)
� OPEX reductions …
– Primary objective!
– Network operations increasingly complex
– Less human involvement in
– Network planning/optimisation
– Performance monitoring, drive testing
– Troubleshooting
Coverage GSM
Coverage EDGE
Coverage UMTS
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
SELF-ORGANISATION: EXPECTED GAINS (1/2)
� … and CAPEX reductions …
– Efficiency improvement � delayed capacity expansions
– smart eNodeBs may however be more expensive
� … and performance enhancements
– Enhanced service availability (robustness, resilience), QoS
IMPACT OF 'SELF-HEALING'
0 20 40 60 80 100
TIME
LO
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LIT
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SITEFAILURE
WITH SELF-HEALING:QUICK RECOVERY
TO TOLERABLE LEVEL
WITHOUT SELF-HEALING:DRAMATIC DROP
TO INTOLERABLE LEVEL
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
� Main objectives of SOCRATES
– Development of concepts, methods and algorithms for self-
organisation
– e.g. handover parameters, antenna parameters, admission control
parameters, …
– Specification of architectural requirements
– measurements, interfaces, protocols
– Assessment of the operational impact
– e.g. radio network planning, capacity management, …
SOCRATES: OBJECTIVES
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
FP7 SOCRATES
Overview
� FP7 SOCRATES
– Background
– Approach
– Use cases
– Results
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
SOCRATES: APPROACH (1/2)
9
Defining use cases, assessment criteria, reference scenariosand the framework
Developmentphase
Developing solutionsfor individual use cases
Integrationphase
Integrating use casesinto an overall solution
Requirementsphase O
VE
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0 200 400 600 800 1000 1200 1400 1600 18000
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scenario 3
t [s]
n u
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sers
in n
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reference
with load balancing
• Three phases
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
SOCRATES: APPROACH (1/2)
� Evolutionary approach towards self-optimisation
– Take current architecture as starting point
– Works quite well, when parameters are properly tuned …
– ‘Make’ existing functionalities ‘self-optimising’
– E.g. RRM mechanisms, …
– Determine actual need for self-optimisation by sensitivity analysis
– Algorithms for ‘automatic’ adaptation of parameters
– Required architectural modifications � impact on standardisation
– Measurements, interfaces, signaling, …
� Many ‘use cases’ defined and investigated
– Stand-alone functionalities
– Interacting functionalities
– coordination needed!
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
SOCRATES USE CASES (stand-alone functionalities)
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Self-optimisation
Handover parameter optimisation
Self-configuration Automatic generation of initial params
Self-healing Cell outage management
SON enabler X-map estimation
Load balancing
Packet scheduling optimisation
Admission control optimisation
Interference coordination
HeNB handover optimisation
HeNB interference and cov. optimisation
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
SOCRATES USE CASES (integrated functionalities)
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Self-optimisation
Admission Control and Handover Optimisation
Load balancing and Handover Optimisation
Macro & Home eNodeB Handover Optimisation
Packet Scheduling and Interference Coordination
� Combinations of use cases where there is either a control parameter conflict or an observability dependency
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
FP7 SOCRATES
Overview
� FP7 SOCRATES
– Background
– Approach
– Use cases
– Results
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
MAIN PROJECT RESULTS (1/2)
� Framework for development of self-organisation methods
– high-level guidelines, requirements, …
� Assessment criteria and methodologies
– OPEX, CAPEX, performance gains
– reference scenarios
� Self-organisation methods and algorithms for selected use cases
– stand-alone
– integrated
localrevenue
time
localrevenue
time
repair time
manualdetection
time
eNodeBdies
eNodeBrevived
repair time
regained revenue due tocell outage compensation
regained revenue due tocell outage detection otherwise
missedrevenueCASE WITH
SELF-HEALING
CASE WITHOUTSELF-HEALING
localrevenue
time
localrevenue
time
repair time
manualdetection
time
eNodeBdies
eNodeBrevived
repair time
regained revenue due tocell outage compensation
regained revenue due tocell outage detection otherwise
missedrevenueCASE WITH
SELF-HEALING
CASE WITHOUTSELF-HEALING
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
MAIN PROJECT RESULTS (2/2)
� SON coordination framework
– alignment of interacting SON functions
� Measurements, architecture & interfaces for SON
– based on use case studies, SON coordinator
� Demonstrations
– visualisation through simulation
– validation
� Implications of SON (ongoing work)
– network planning & operations
AUTOGNOSTICS
POLICY
ALIGNMENTIncl. Guard function
NETWORK SUBSYSTEM (e.g., eNB, neighbours, OSS, NMS)
OPERATOR
SONFUNCTIONS
POLICYinterface
performancequality metric
change requests
objectives
feedback onperformance
SON System
SONFUNCTIONS
SON
FUNCTIONS
SON
FUNCTION
specify data
requests
objectives & constraints
performance data
configuration
changes
performance data
feedback & constraints
control parameterinterface
raw measurements &configuration changes
Communication with peers
Note SON system will often be in the
eNB, but could be in any node
AUTOGNOSTICS
POLICY
ALIGNMENTIncl. Guard function
NETWORK SUBSYSTEM (e.g., eNB, neighbours, OSS, NMS)
OPERATOR
SONFUNCTIONS
POLICYinterface
performancequality metric
change requests
objectives
feedback onperformance
SON System
SONFUNCTIONS
SON
FUNCTIONS
SON
FUNCTION
specify data
requests
objectives & constraints
performance data
configuration
changes
performance data
feedback & constraints
control parameterinterface
raw measurements &configuration changes
Communication with peers
Note SON system will often be in the
eNB, but could be in any node
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
SOCRATES – DISSEMINATION OF PROJECT RESULTS
� Project deliverables, publications, presentations, …
� Organisation of workshops
– at ICT Mobile Summit 2009, Santander, June 2009
– joint SOCRATES / COST2100 workshops– Braunschweig, February 2009
– Athens, February 2010
� Demonstration stand at Future Networks & Mobile Summit 2010
– Florence, June 2010
� Interactions with NGMN
� Liaisons to 3GPP
– several contributions delivered and planned
http://www.fp7-socrates.eu
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
SOCRATES – FINAL WORKSHOP
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
1. SOCRATES Overview (15 min)
2. SON Concepts in SOCRATES (15 min)
a) Assessment Criteria
b) SON Coordination
Q&A (5 min)
3. SON Simulation Demo’s (30 min)
a) Home eNodeB
b) Handover
c) Load Balancing or Cell Outage Compensation
Q&A (10 min)
Outline
18/17
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Outline
� Assessment criteria for self-organising networks
– Introduction
– Metrics
– Performance / Coverage / Capacity
– OPEX
– Benchmarking approach
� Coordination of SON use cases
– Overview
– Policy Function
– Alignment Function
– Guard Function
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Introduction
� Why define assessment criteria?
– Evaluation of SON algorithms
– Comparing multiple algorithms: Which algorithm is best?
– Fine-tuning of an algorithm to optimise its performance
– Assessment of the gains that can be achieved using SON
– By comparison with manual network operation
– Essential part of development of algorithms
– But also useful for SON trials!
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Metrics: Performance – Coverage – Capacity
Performance(GoS/QoS)
GoS (Grade of Service)Call blocking ratio, call dropping ratio, …
Coverage Service coverage, data rate coverage, …
CapacityMaximum supportable traffic load, spectrum efficiency, …
QoS (Quality of Service)Packet delay, packet loss ratio, transfer time, throughput, MOS, fairness, …
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‘Conventional’ metrics, but important for SON
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Metrics: OPEX
� OPEX reduction is often quoted as an important SON gain
– Important to be able to quantify the impact
� In the SOCRATES approach:
– OPEX without SON is determined by summing together all components that
contribute to OPEX
– OPEX with SON is determined by assessing impact on various components
– Difference is then assessed
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Determining OPEX savings – Methodology
� OPEX without SON1. Determine effort for an individual task
– Task is defined as optimising or adjusting a parameter or parameter set
2. Determine OPEX per task, per network, per year
– Cost per task (Euro) = Effort per task (days) × Cost per day (Euro)
– OPEX per task / year = (Cost per task) × (#Changes per network) × (#Changes per year)
3. Determine total OPEX per year
– OPEX / year = SUMall-tasks(OPEX per task / year)
� OPEX with SON: use the same method as for ‘without SON’, but assess impact on different components
– In some cases OPEX may be reduced to zero, but definitely not always
� Can the SON algorithm completely autonomously:– Obtain the required inputs?
– Analyse the available data?
– Determine new parameter settings?
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Benchmarking: Overall assessment
� Approaches to determine overall assessment:
– Single target metric, with constraints on the other metrics
– Combining different metrics using a utility function (with possible constraints on
additional metrics)
� Absolute gains:
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Operator invests very little
in manual optimisation
Operator invests a lot inmanual optimisation
Gain is mainly in
network quality
Gain is mainlyOPEX reduction
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Why SON Coordination?
� The research and development work on SON has up to now concentrated on
stand-alone functions
� With an increasing number of SON functions, the likeliness of conflicting
goals and targets of the individual SON functions also increases
� The goal of SON coordination is to avoid or resolve potential conflicts, and
provide a single interface towards the operator regarding policies
SON
Function A
SON Function
B
MetricA
MetricB
P1
P2
P3
P4
SON
Function A
SON Function
B
MetricA
MetricB
P1
P2
P3
P4
SON Function
A
SON Function
B
Metric
A
MetricB
P1
P2
P3
P4
SON Function
A
SON Function
B
Metric
A
MetricB
P1
P2
P3
P4
Control Parameter Conflict Observability Dependency
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
SON Coordinator Framework - Overview
THE OPERATOR
NETWORK SUBSYSTEM
Policy Function
SON System
Guard Function
Alignment Function
Communi-cation with
Peers
Auto-gnosticsFunction
SON Functions
THE OPERATOR
NETWORK SUBSYSTEM
Policy Function
SON System
Guard Function
Alignment Function
Communi-cation with
Peers
Auto-gnosticsFunction
SON Functions
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Policy Function
OperatorPolicy
FunctionSON Func. A
Policy
SON-specific policies – these change according to cell type
High-level performance
objectives, e.g., accessibility, retainability
Guard
Align-
ment
Auto-gnostics
SON Func. B
Policy
SON Func. C
Policy
OperatorPolicy
FunctionSON Func. A
Policy
SON Func. A
Policy
SON-specific policies – these change according to cell type
High-level performance
objectives, e.g., accessibility, retainability
Guard
Align-
ment
Auto-gnostics
SON Func. B
Policy
SON Func. B
Policy
SON Func. C
Policy
SON Func. C
Policy
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Alignment Function
ArbitrationShort-term
driven, conflict
resolution
Network Subsystem
Trigger
SO
N
Fu
nctio
n
ActivationCause analysis, management of
SON functions
Policy Function
Alignment Function
Gu
ard
F
un
cti
on
Requests
Feedback,
Notifications,Settings, Start/Stop
Arbitration, Activation & Cause Analysis Settings
Confirmed Parameter Changes
ArbitrationShort-term
driven, conflict
resolution
Network Subsystem
Trigger
SO
N
Fu
nctio
n
ActivationCause analysis, management of
SON functions
Policy Function
Alignment Function
Gu
ard
F
un
cti
on
Requests
Feedback,
Notifications,Settings, Start/Stop
Arbitration, Activation & Cause Analysis Settings
Confirmed Parameter Changes
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Guard Function
Guard
FunctionOscillation Detection
Absolute Performance Surveillance
Data request definitions
Align-
mentFunction
Auto-
gnosticsFunction
Policy
Function
Performance,Fault, Config. Data
Triggers
Settings for the detection of extreme network behaviour
Guard
FunctionOscillation Detection
Absolute Performance Surveillance
Data request definitions
Align-
mentFunction
Auto-
gnosticsFunction
Policy
Function
Performance,Fault, Config. Data
Triggers
Settings for the detection of extreme network behaviour
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Questions
30/17
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
SOCRATES Simulation Demo’s
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
1. SON Simulation Demo’s
a) Handover
b) Load Balancing or Cell Outage Compensation
c) Self-optimisation of Home eNodeBs
Q&A
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Handover self optimisation
� Possible handover problems:
– HPIHOF: Handover failures (too early, too late)
– HPIHPP: Ping-pong handovers
– HPICD: Call dropping
HP = w1HPIHOF + w2HPIHPP + w3HPICD
� Objective
– Minimization of HP via automatic adjustment of hysteresis and time to trigger (TTT)
Ping-pong
time
HO Drop
X
33/17
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Handover self optimisation approach
� Off-line HO system behaviour
– System level simulations with different hysteresis and time-to-trigger
– Define operating region
34/17
� Derive on-line (self-) optimisation
– Start within the operating region
– Change HYS and/or TTT and measure handover performance (HP)
– If HP improved further change in same ‘direction’. Otherwise change in other ‘direction’. 1 2 3 4 5 6 7 8 9 100
0
Hysteresis [dB]
0.04
0.064
0.08
0.1
0.128
0.16
0.256
0.32
0.48
0.512
0.64
1.024
1.28
2.56
5.12
Legend
Possible HOP
Allowed HOP
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Handover demo (Thomas Janssen, TU Braunschweig)
35/17
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Load balancing self optimisation
� Possible load problems:
– Users concentrated in one cell i.e. unequal load distribution causing cell overload
– Users cannot be served with the required quality due to lack of resources
� Objective
– Load transfer from overloaded cell towards neighbour cells via automatic updates of HO offset
– Maximise number of satisfied users
SeNB TeNB
Hysteresis
Distance
SeNB TeNB
SeNB TeNB
LB HO offset
Hysteresish1
h2
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Load balancing self optimisation approach
� Estimate DL and UL load at target cell after
load balancing
– Based on DL and UL SINR estimation
– UEs do not change location during load balancing
� Decide which and how many UEs from
overloaded cell should be transferred
� Decide which neighbour cells will accept the
overload traffic
� Adjust HO offsets and send HO commands
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Load balancing demo (Szymon Stefanski, NSN)
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Cell outage compensation self optimisation
39/17
� Cell outage problems:
– Lost of coverage
– Unsatisfactory users and lost of revenue
� Objective
– Coverage (partially) restored by neighbour cells via automatic updates of e.g. antenna tilt, or uplink open loop power control operating point P0
– Maximise number of served users under the constraint that UL and DL quality target at neighbour cells are above thresholds
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Cell outage compensation self optimisation approach
QUL QDL
Quality target
checkL
� Measure UL and DL quality at neighbours
� Quality target check
– QUL <> QT,UL
– QDL <> QT,DL
� Adjust control parameters accordingly
– Decrease/increase DL power/tilt
– Decrease/increase P0
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Cell Outage Compensation Demo (Mehdi Amirijoo, Ericsson)
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
HeNB handover optimisation: Introduction and scenario
� Handover optimisation in scenario with
open access Home eNodeBs (HeNBs)
� HeNBs are placed indoors, but provide
coverage to outdoor users
� The objective is to determine how to
effectively use open access HeNBs
– Reliability: Minimise dropped calls due
to bad SINR conditions at handover
– User experience: Maximise the
throughput that the user is experiencing
� Optimisation for HeNB scenario may be
different than for macro-only scenarioFigure shows best server based purely on signal strength
X (m)
Y (
m)
-200 -100 0 100 200 300 400 500 600 700-500
-400
-300
-200
-100
0
100
200
300
400
500
3x3 layout of HeNBs
3 sector macro site
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Handover optimisation algorithm
� Statistics (HPI = Handover
Performance Indicator) used as input to
the algorithm are:
– Dropped call ratio (CDR)
– Ping-pong handover ratio (PPHR)
� Metrics are calculated separately for
each type of handover
– ‘X’ can be M (= Macro) or H (=Home eNodeB)
� Start values:
– PPHRThreshold = 0.1
– CDRThreshold = 0.1
– Hysteresis = 5 dB
– TTT = 320 ms (fixed)
PPHRX < PPHRThresholdX
CDRX > CDRThresholdX
Decrease CIOX by 1 dB
PPHRX > PPHRThresholdX
CDRX < CDRThresholdX
Increase CIOX by 1 dB
PPHRX < PPHRThresholdX
CDRX < CDRThresholdX
Decrease HPI thresholds by 0.02
PPHRX > PPHRThresholdX
CDRX > CDRThresholdX
Increase HPI thresholds by 0.02
Algorithm
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Macro & HeNB – Simulation results – Call drop ratio (CDR)
SON activated – start values: Hyst=5 dB, TTT=320 ms
No SON – param. values: Hyst=3 dB, TTT=320 ms � Ping-pong handover ratio increases for macro-macro handover
� Ping-pong handover ratio is negligible for all other handovers
0 100 200 300 400 500 6000
10
20
30
40
50
60
70
80
90
Time (s)
Call
dro
p r
atio (
%)
Macro-macro CDR - No SON
Macro-macro CDR - SON activated
HeNB-HeNB CDR - No SON
HeNB-HeNB CDR - SON activated
Even with SON, HeNB handover performanceis still an issue (for the considered scenario)
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Questions
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Hans van den Berg (TNO), Ljupco Jorguseski (TNO), Neil Scully (Vodafone)
Contact Details
� Hans van der Berg (TNO)– [email protected]
– +31 88 8667031
� Neil Scully (Vodafone)– [email protected]
– +44 7919 994699
� Ljupco Jorguseski (TNO)– [email protected]
– +31 88 8667154
� Thomas Jansen (TU Braunschweig)– [email protected]
� Szymon Stefanski (NSN)– [email protected]
� Mehdi Amirijoo (Ericsson)– [email protected]
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