Self Organizing Networks (SON)
Overview
Drivers for Self Organizing Networks
• • • •
• •
Parallllel Para el oper operat atio ion n of of LTE LTE with ith 2G 2G and and 3G netw networ orks ks Larg Large e and and comp comple lex x num numbe berr and and stru struct ctur ure e of of net netw work ork para parame mete ters rs Expanding nu number of of Ba Base Stations OPEX reduction - Reduce hu human in interaction
Config Conf igur ure e & opti optimi mize ze the the netw networ ork k aut autom omat atic ical ally ly Butt all Bu allow ow the the ope opera rato torr to be the the fin final al con contr trol ol inst instan ance ce
Main Functionalities of SON Self-configuration (Plug and Play): • Automated network integration of new eNB by auto connection and auto configuration
Self-healing (Auto Repair): • Automatic detection and localization and removal of failures:
• Simplified installation, faster roll out • Automated neighbour configuration (X2) • Physical Cell ID
• Cell Outage Detection and Outage Mitigation • Automatic Alarm Reaction
Self-optimization (Auto Tune): • Auto-tune the network (coverage and
Self-planning: • Dynamic re-computation
capacity) with the help of UE and eNB measurements on local eNB level and/or network management level
• • • • •
Energy savings Mobility Robustness Load Balancing RACH Optimization Inter-cell interference coordination
• HW/SW-Failure HW/SW-Failure Mitigation
of network plan due to capacity extensions, traffic monitoring or optimizations
• Often going along with self-optimization (efficient way of network growth support)
3GPP: SON in Standardization 2007 2008
2008 2009
2009
2010
2010
SON in 3GPP Rel. 8 • Automated configuration of Physical Cell ID • ANR
Rel. 9 • Remaining/spill over(s) Rel. 8 • Automated configuration of Physical Cell ID
• Inter RAT ANR • Self-configuration of eNBs • Automatic Software Management
• Automatic Radio Configuration •
Self Configuration
• • • •
Function Coverage and Capacity optimization Mobility Load Balancing Mobility Robustness optimization Avoidance of Drive Tests SON Evaluation Scenario
Rel. 10 • Interference Reduction • Inter Cell Interference Coordination
• Coverage and Capacity optimization (spill over, new features like relays) • Mobility Robustness optimization (spill over, new features like relays) • Energy Savings • Control and Resource optimization of Relays
Self Optimization RAN3 • Cell outage compensation/ mitigation
Self Healing
• Self Healing
SA5
SON Featur Features es Exam Examples ples Self Configur Configuration ation
SON:: LTE SON LTE BTS Plu Plug’n g’n Pla Play y One touch deployment
Factory Assembly & Pre-Configuration
One Touch deployment : • Auto connection to the network with PKI based node authentication • Auto configuration of SW and configuration data • Automated deployment of licenses • Automated integration into the acce access ss-- core core-- and and netw networ orkk-
On-site installation (Field service)
Auto connection & configuration, remote commissioning
Network Management
eNB
MME
SAE-GW / PDN-GW
Self Configuration Procedure NetAct SON Coordinator
IP Backhaul NetAct Services 4. Auto SW & Configuration download
5. Auto X2 set-up
Certification & Registration Authority
3. Authentication & PKI Certificate Download
GW 6. Auto S1 set-up 1. auto-connect to backhaul
MME
2. IP address allocation
DHCP Server PKI = Public Key Infrastructure DHCP = Dynamic Host Control Protocol
PCI Management Automated PCI assignment and collision detection • • •
Each cell of a LTE network needs to have a Physical Cell ID (PCI) ( PCI) assigned Since the PCI range is limited to 504 values neither the neighbours of a cell, nor the neighbours neighbours of the neighbours shall have the same PCI value Handling phases: 1) Central optimized assignment for initial PID assignment for Flexi Multiradio BTS via NetAct Optimizer •
PCI assigned based on distance and actual adjacencies
2) Collision Detection with alarming in Flexi Multiradio BTS • •
Collision: two neighbour cells with the same PCI During the X2 setup the neighbour information is exchanged, Flexi Multiradio compares its own PCI with the ones of the neighbours activating an alarm if collision
3) Automatic Collision Resolution via NetAct Optimizer •
If collisions detected (via alarm) then optimization can be manually or automatically triggered several times a day
Feature ID: LTE468
Automated Neighbor Relation (ANR) Configuration •
Neighbour Neighbour relations are important as wrong neighbour definitions cause HO failures and dropped calls Self configuration of relations avoids manual planning & maintenance
•
ANR covers 4 steps: 1) 2) 3) 4)
•
Neighbour Neighbour cell c ell discovery Neighbour Neighbour Site’s X2 transport configuration discovery (i.e. Neighbour Neighbour Site IP@) X2 Connection Set-up with neighbour cell configuration configurati on update ANR Optimization
The scope within ANR is to establish an X2 connection between source and target nodes nodes and for that that it is necessary necessary that source eNB eNB knows the target target eNB IP@ How the source eNB eNB gets the IP@ differentiates differentiates the ANR features: features:
• – – –
Central ANR (RL10) ANR (RL20) ANR- Fully Fully UE based based (RL30) (RL30)
3GPP ANR Configuration Principle Neighbor Site eNB - B
UE connected
Site eNB - A
MME
New cell discovered New cell identified by ECGI
S1 : Request X2 Transport Configuration (ECGI)
relays request
S1: Request X2 Transport Configuration CM S1: Respond X2 Transport Configuration (IP@) S1 : Respond X2 Transport Configuration (IP@) CM Add Site & Cell parameter of eNB-A
X2 Setup : IPsec, SCTP, X2-AP [site & cell info] CM
CM
Add Site & Cell Parameter of eNB-B
relays response
ANR - Fully UE Based Automated Autom ated planning: planning: NO configuratio configuration n of any neighbor cell attributes, attributes, no OAM needed
• Fully 3GPP compliant • UE triggers X2 establishment first when unknown PCI is measured • UE is asked to measure ECGI by source eNB • Source Source eNB eNB sends sends ECGI ECGI to MME
eNBID#B
eNBID#A
• MME requests IP connectivity information (IP@) to the target eNB • MME forwards forwards the target eNB IP@ to the the source eNB •Source eNB established a X2 connection to the target neighbour neighbour sites • X2-set up message used for exchange of all required neighbour information
X2-Interface S1-Interface
MME S1-Interface
Advantage • No manual neighbour planning • requires SON/ANR supporting UE (report ECGIs)
PCI: Physical Cell ID ECGI: E-UTRAN Cell Global Identifier
Central Centr al ANR (Auto (Automatic matic Neigh Neighbou bourr Cell Relati Relation) on) Self Configuration of Neighbour Relations for LTE
• UE measurements are not taken into account • Central solution solution purely purely based in O&M: NetAct Configurator and NetAct Optimizer • Optimizer creates neighbours for each site, then Configurator adds the IP@ to the list and and this is downloaded downloaded to the sites with with the configuration data. - Neighbour relations (X2 paths) are already established as part of the configuration - UE measurements measurements are ignored: if UE detects an unknown unknown neighbour (not part of the neighbour list created by Optimizer) this is ignored
LTE ANR Automated Auto mated planning: planning: NO configurati configuration on of any neighbor cell attributes attributes •NetAct Optimizer and Configurator Configurator create the list of potential potential neighbour neighbour cells and related related IP connectivity information •When UE reports an unknown PCI the source eNB looks for that PCI in look-up tables to find the IP@ of the site hosting the PCI reported UEs measurements taken into account to trigger the X2 connection •Once known target eNB IP@ the X2 connection is established and information between neighbours is exchanged Advantage: •Works with any UE (no need to report ECGI) •No neighbour site planning required Feature ID: LTE492
Features Supporting Inter-RAT ANR Automated planning on central NMS level NetAct
• Automated planning of UTRAN/GSM neighbours neighbours done via NetAct Configurator and Optimizer • 2G/3G relevant data for Inter RAT relations is uploaded/retrieved uploaded/retrieved from the existing configuration management database
Optimizer
CM
Configurator
CM
• Optimizer calculates neighbour sites given by geo-locations • Configurator configures the neighbour neighbour cell lists and downloads downloads the plans
LTE GERAN UTRAN
UTRAN/GERAN Domain Managers
• No UE supporting UTRAN-ANR needed UTRAN GERAN
CM
Synchron Syn chronization ization of InterR InterRA AT Neigh Neighbours bours Always up to date neighbour relations • Enhancement Enhancement of Inter RAT ANR previous features • Update/synchronize Update/synchronize automatically changes of Inter-RAT neighbour neighbour information in case of relevant changes at the 2G/3G or LTE-side ensuring up-to-date Inter RAT neighbour neighbour relationships • Changes to trigger update: – Site/cells addition deletion – Cell parameter changes • Alignment to LTE network through NetAct • Synchronization Synchronization processes can be run automatically, be scheduled or triggered manually by operator
Optimizat Optimi zation ion of Neig Neighbo hbour ur Rel Relatio ations ns NetAct Net Act Op Optim timizer izer (Intr (Intra-L a-LTE) TE) Automatic neighbour relationship evaluation. OPEX reduction in managing mana ging neighbour relationships
• NetAct Optimizer supervises supervises the quality of the registered registered neighbour neighbour relations. Inefficient neighbour relations may be blacklisted for HO • Analysis based on HO performance counters and configuration information • Use cases: • Neighbou Neighbours rs will insufficient HO performance can be blacklisted • Blacklisted Neighbours can be whitelisted (e.g. to re-evaluate the performance due to changes in topology) • Neighbours can be marked by an operator so they are excluded from optimization. optimization. • Optimization works in a mid to long term schedule Feature ID(s): LTE 771
Optimizer CM
Configurator
No HO
PM
PRACH Management • Automatic assignment assignment of PRACH parameters parameters during during the initial initial eNB auto-configuration auto-configuration process • Configured PRACH parameters: • prachConfInd prachConfIndex, ex, prachFreqOff, prachCS, rootSeqInd rootSeqIndex ex • Assignment done for all cells of an eNB • Considering: • Own cell data • Configuration Configuration data from ‘surrounding’ eNBs incl. subordinate subordinate cells cells • Feature delimitation: • No PRACH / RACH optimization • Based e.g. on counter or PM counter results • Does not change any any data from from ‘surrounding’ ‘surrounding’ eNBs and their their subordinate cells cells • Runs only once during initial auto-configuration process • Benefit • No manual PRACH planning for new eNBs/cells required
SON Featur Features es Exam Examples ples Self Healing
Self Healing: Cell Outage Detection • Key Performance Indicators are evaluated to determine if • • •
•
there can be a problem in the cell The tools of NetAct “Thersholder & Profiler” are used to provide the alarm generation in case of a problem The feature rises an indication that there may be a problem so that the operator must still check the situation The failure scenarios are: • Cell availability • RACH failure rate • RRC connection setup failure • Data radio bearer setup failure rate • PDCP cell throughput • Uplink power measurements To prevent false alarms KPIs are performed to hystorical KPIs result values Feature ID(s): LTE432 Cell Outage Detection
Self Healing: Cell Outage Triggered Reset Automated cell service recovery NetAct 3 • Base Based d on on ser servic vice e ala alarm rm ra raise ised d by by Cel Celll Outa Outage ge Detection • Ne NetA tAct ct wor workf kflow low is tri trigg gger ered ed au auto toma mati tica calllly y • Au Auto toma mate ted d tri trigg gger ered ed ac acti tion on:: Res Reset et of BT BTS S • Al Ala arm cl cle eare red d wit with h act actio ion ns
Analyze the alarms and status of eNB
Thresholder & Profiler
Create and send commands for action: Reset Cell or eNB
2 NetAct
LTE432 Cell Outage Detection r o t i n o M
correlation
1 Feature ID(s): LTE502
BTS Site Manager
Alarms, Counters
4
SON Featur Features es Exam Examples ples Self Optimiz Optimization ation
Mobility Robustness (MRO) Increased network performance by automatic adaptations • Optimizing the Intra-LTE (Intra-frequency) radio network HO-configuration for robustness of mobility procedures (i.e. to avoid drops calls and radio link failures due to too early/late HOs)
• MRO fine tunes tunes based on on long-running long-running evaluation of KPIs KPIs / specific detections detections in eNBs / influenced by operator policies
• Fine tuning refers to the adjustment of HO related thresholds like HO offsets and Time to Trigger
Optimizer/Configurator
PM-history NetAct
Height
MRO -SF
MRO -SF
Measurement data Measuremant data
CM
Performance Measurements
PM
CM
PM
Feature ID(s): LTE 533
Minimization of Drive Test (MDT) • LTE953 is a feature designed to replace replace currently expensive expensive drive testing and and is intended intended for use during during network deployment, optimisation and operation • LTE953 is an automated ‘utilization’ feature of trace-related features LTE570 and LTE644: LTE953
ReportInterval ReportAmount
LTE644 Configurable Cell Trace Content
Collected cell trace data
LTE570 Periodic Measurements ITFs and elementary procedures for tracing •
LTE953 logic flow:
– – – –
Trace parameters parameters are sent from NetAct NetAct TraceViewer TraceViewer to eNB via iOMS. NetAct TraceViewer triggers triggers eNB to start trace session Capable Capa ble MDT UEs provide provide measur measureme ements nts when when triggere triggered d by eNB due to trace trace start start Measure Measurement ments s are sent sent to NetAct Trace Trace Viewer Viewer for post processin processing g and presenta presentation tion
Minimization of Drive Test (MDT) MDT profiles •
LTE953 MDT profile is a combination of selection rule, rule, UE limitation rule & activation rule which together define the trace session configuration intended to derive target conclusions Selection of of elementary elementary procedures procedures included included in trace session – Selection rule: Selection
Examples: RRCConnectionReestablishment, RRCConnectionReestablishment, S1 Uplink NAS Transport, X2 RLF Indication, ...
UE connections which which have to be covered covered by trace session – UE limitation rule: Upper limit of UE Activa ivatio tion n rul rule: e: Set of of feature features s which which have have to be activ activate ated d during during trace trace sessio session n – Act
•
Example: LTE570 Periodic Measurements
Target conclusions can be derived from traced data via postprocessing rules – Postprocessing rules are not part of LTE953, but they implicitly define the MDT profile
•
Target conclusions defining LTE953 MDT profiles concern coverage ... – ... quality measurement – ... problem detection – ... problem localization
Potential coverage problems Traced cell
Full SON support for distributed sites LTE1045
eNb
10km
RRH
NetAct would use co-ordinates of eNb, now can use co-ordinates co-ordinates of remote Antennas. Antennas. This info used in; • • • • • • •
PCI management ANR Auto config PRACH management ANR Inter RAT UTRAN ANR Inter Rat GERAN Sync of Inter RAT neighbors
20km
RRH
THAN !O"
