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LTE/LTE-A SON  for Femtocells
 

LTE/LTE-A SON for Femtocells

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  • Jogando.net/mu - 03

    Olá, venho divulgar o melhor servidor de MU on-line do
    Brasil.
    -Season 6 Ep. 3 em todos os Servers. Sendo 7 servers diferenciados proporcionando sua diversão,
    VEJA ALGUMAS NOVIDADES :
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    It's a great to understand SON. could you send it to me for self study. Thanks a lot.
    Peter
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    LTE/LTE-A SON  for Femtocells LTE/LTE-A SON for Femtocells Presentation Transcript

    • LTE/LTE-A SON (for Femtocells) Mischa Dohler CTTC, Spain Manuel Palmowski & Dimitri Marandin mimoOn, GermanyCopyright © 2009 BeFEMTO– Broadband Evolved FEMTO Network. All Rights reservedCopyright © 2009  BeFEMTO–Broadband Evolved FEMTO Network. All Rights reserved. 1
    • System Degrees of Freedom [1/2] Degrees of Freedom (DOF) / Area:  new system DOF = old system DOF                x 20‐30  new system density = old system density     x 4  new DOF/km2 = old DOF/km2                       x 100 1E+12 1E+10 00000000 1000000 CELLULAR + WIFI + FEMTO CELLULAR + WIFI 10000 CELLULAR 100 1 GSM EDGE UMTS HSPA LTE LTE‐A Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 2
    • System Degrees of Freedom [2/2] With femtocells, the DOF  increases significantly! [presented by Interdigital: Globecom’11 – IWM2M, Houston] Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 3
    • Likelihood of Failure/Outage Important High‐Level Insides:  DOF/area increases  failures/outages increase: [© http://www.sciencedirect.com/science/article/pii/S0951832004000031]  loss in revenue if nothing done, and/or  very costly if addressed by human labour Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 4
    • Importance of SON  Previously Manual Processes:  reduce manual intervention for deployment savings  automate repetitive processes  examples: automatic planning & self‐configuration  Too Fast/Complex Processes:  improve run‐time operation based on real‐time data  automate optimization of critical network elements  example: self‐optimization & self‐healing  SON automation, however, is not new but rather a  further evolution of prior automation efforts Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 5
    • Elements of SON  Important Elements:  elements of “autonomous”  elements of “distributed”  elements of “intelligent/cognitive”  elements of “optimality”  SON ≠ SON:  despite large DOF, SON has to be (close to) optimal  since it makes no sense to have a system with amazing  components which however underperforms due to poor  “management” Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 6
    • SON in Cellular Networks Automated  Planning Planning Self  Configuration Deployment Self  Optimisation/ Optimisation Maintenance Self        Healing Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 7
    • Presentation Overview 1. SON in NGMN & 3GPP LTE 2. SON Architectural Elements 3. 3GPP SON Features 4. 3GPP SON Functional Details 5. Conclusions Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 8
    • 1. SON in NGMN & 3GPP LTECopyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 9
    • NGMN’s Input To SON Next Generation Mobile Networks  (NGMN) Alliance:  created in 2006 by group of operators  business requirements driven  often based on use‐cases of daily  networking routines  NGMN and SON:  SON input to 3GPP since 2006  10 SON use cases have been defined  (see right) which input to 3GPP Rx  QoS SON is likely to appear shortly Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 10
    • 3GPP High‐Level Structure Management!  maintenance/  maintenance/  system   CN interfaces,  development development architecture, service  protocols,  of GSM/GPRS/ of UMTS/HSPA/ capabilities, codecs  interworking, IMS,  EDGE RAN LTE RAN (inc. EPC)  terminals, SIM   Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 11
    • SON in 3GPP LTE Release 8 3GPP R8 is about eNB self‐configuration:  automatic neighbor relation  automatic physical cell ID (PCI) assignment  automatic inventory  automatic software download Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 12
    • SON in 3GPP LTE Release 9 3GPP R9 is about network optimization procedures:  mobility robustness and handover optimization  RACH optimization  load balancing optimization  inter‐cell interference coordination (ICIC) Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 13
    • SON in 3GPP LTE‐A Release 10 3GPP R10 is about overlaid networks:  coverage & capacity optimization  enhanced ICIC  cell outage detection and compensation  self‐healing functions  minimize drive test  energy savings Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 14
    • SON in 3GPP LTE‐A Release 11 3GPP R11 will be about heterogeneous networks:  automated network management  troubleshooting   multi‐layer, multi‐RAT heterogeneous networks  among other issues Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 15
    • 3GPP SON Status Rel8 Rel9 Rel10 ANR PCI_Sel. MLB, MRO, RACH MLB, MRO,CCO RAN Energy Saving (ES) Minimize Drive Test (MDT) PCI_Selection Energy Saving SA5 MDTANR = Automatic Neighbor RelationPCI  = Physical Cell IDMLB = Mobile Load Balancing Self‐HealingMRO = Mobility Robustness Opt.RACH = Random Access Channel SON MgmtCCO = Capacity & Coverage Opt. Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 16
    • 2. SON Architectural ElementsCopyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 17
    • SON Architecture Approaches [1/2] Levels of SON Execution:  localised: autonomous SON  NM SON execution based on purely local  information at (H)eNB & UE  distributed: autonomous SON  DM/EM DM/EM execution based on information  exchanged with neighbouring  SON SON (H)eNB (eg via X2 interface)  centralized: decision taking  based on (fairly complete)  system information (eg at  NM/DM/EM levels) X2 SON SON  hybrid: any mixture of above NM = Network Management DM = Device Management EM = Element Management Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 18
    • SON Architecture Approaches [2/2] centralized           distributed  localised hybridKPI = Key Performance Indicator Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 19
    • Key Time Intervals  For Centralised SON, timing is important:  Collection Interval: time period during which statistics  and data are collected; limited by vendor’s OAM  bandwidth; typical 5min (i.e. not at scheduling level!)  Analysis Interval: time period needed to draw decision;  typically several collection intervals (filtering effect by  considering also prior data history)  Change Interval: time period between executing the  changes in the network; typically limited by system’s  operational constraints Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 20
    • Important SON Trade‐Offs faster & less prone to “single point of failure” info from number of cells/RATs Centralised Distributed Localised multiple cells normally  ca. 2 cells adv. RRM long term statistics uses X2 small impact on ncells uses OAM  short term statistics multi‐vendor/multi‐ multi‐vendor (X2)  RAT self‐configuration handover opt. scheduler opt coverage optimisation load balancing Link adapt. opt (load balancing) RACH opt RACH opt Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 21
    • Coordinated SON Model  very difficult to standardise: management  lots of different ways to  implement a SON function are  possible  e.g. load balancing (LB) done  at NM level but handover (HO)  optimization done at eNB level  and both want to adjust the same  parameter in eNB decision taking feedback  practical way around today:  if function at NM level,  “configure” is standardised execution  at eNB level not standardised  currently primary & secondary  targets are defined [based on S5‐102029] Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 22
    • BeFEMTO HeNB Architecture Management Functions Perform. Mgmt SON Enabling Functions Fault Diag. Coverage  Network  Context Positioning Probe Estimation Sync Learning … Security network users SO-RRIM Local Netw Radio SON  Sub-functions Elem Agent Coordinator EAP‐ Energy SOAP  AKA Saving RPC Network SO‐RRIM S1AP/ Mobility  Functions HTTPS IKEv2 RRC X2AP Control GTP‐U PDCP Load Local TCP/ Balancing Location TCP SCTP UDP Mgmt. UDP RLC Admission Control IP/IPsec MAC Scheduler Routing … Geo Sublayer BB MAC PHY NMM PHY RF S1 / X2 / Type 1C / Rt /Lm  interfaces Uu / Un interfaces Network /Mgmt Functions Protocol Stacks Radio Functions Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 23
    • 3. 3GPP SON FeaturesCopyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 24
    • SON in Cellular Networks Automated  Planning Planning Self  Configuration Deployment Self  Optimisation/ Optimisation Maintenance Self        Healing Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 25
    • SON Functions (NGMN & 3GPP) Automated  Self‐Optimisation Planning Self‐ Configuration Self‐Healing Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 26
    • Automated Planning  From “trial & error” to “planning automation”: [© ICT MOMENTUM] Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 27
    • Self‐Configuration  Important Self‐Configuration Functions:  authentication  address allocation  secure OAM tunnel setup  SW installation  inventory management  transport parameters setup  radio parameters setup  self‐test Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 28
    • Self‐Optimisation 3GPP • Automatic Neighbour Relation • Mobility Robustness/Handover Optimisation • (Mobility) Load Balancing • RACH Optimisation • Coverage and Capacity Optimisation • Energy Saving • Interference Coordination • HeNB SON additional from Socrates/NGMN (not discus) • QoS Optimisation (advanced RRM) • Scheduler • admission control • congestion control • link level/L2/HARQ re‐tx/MIMO parameters Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 29
    • Self‐Healing  Important Self‐Configuration Functions:  failure recovery  cell outage compensation Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 30
    • 4. 3GPP SON Functional DetailsCopyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 31
    • eNB Self‐Configuration (Rel. 8) Benefits:   reduction of manual labour  faster and cheaper network deployment Description:   detect transport link & establish connection  download & upgrade software  set up initial configuration parameters  perform self‐test  go into “operational” mode Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 32
    • Benefits:   keeping centralized neighborhood tables is impossible  automating this is one of the most important SON features Description:   keep updated neighborcell (ncell) table through UE  obtain ECGI & IP via MME  to communicate to target eNBECGI = E‐UTRAN Cell Global IdentifierOAM = Operating Administration & MaintenanceMME = Mobility Management EntityRRC = Radio Resource ControlerTCI = Target Cell Identifier Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 33
    • PCI Selection (Rel 8/9) Planned/Centralised PCI  direct value is assigned (3 x 168 = 504 in total only!) SON/Distributed PCI selection  a range of PCIs is given eNB will not select cell IDs that are reported by UEs reported over the X2 interface (not for HeNB as of now) acquired through NW listen mode (will not catch all) select PCI value randomly from the remaining PCIs PCI collisions: >1 eNB seeing each other choose same IDPCI = Physical Cell ID Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 34
    • PCI Selection ‐ Collisions PCI collision probability depends on the number of PCIs  available for such cells PCI reported belongs to two different ECGI Collision recovery 500 non‐macro eNBs (e.g. HeNBs) dropped randomly in each macro eNB [R3‐091018] Number of PCIs Percentage of UEs Percentage of UEs Percentage of UEs available for observing collision of observing collision of PCIs observing collision of PCIs non-macro eNBs PCIs with random PCI with random PCI with random PCI allocation allocation allocation plus downlink plus downlink receiver receiver (sensitivity at -6 (sensitivity at -8 dB) dB) 10 15.2% 12.2% 11.7% 50 3.3% 2.6% 2.4% 100 1.7% 1.3% 1.2% 200 0.9% 0.7% 0.6% Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 35
    • MRO (Rel‐9, ext Rel‐10)Mobility Robustness Optimization (MRO) because …… Handovers (HOs) between same (intra) and different  (inter) radio access technologies (RATs) can go very wrong: too late handover (HO): too early intra‐RAT HO: wrong cell intra‐RAT HO: Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 36
    • MRO (Rel‐9, ext Rel‐10)  Mobility Robustness Optimization  detect radio link connection failures due to being too early, too late handovers or handover to wrong cells  caused by not optimised intra/inter‐RAT handover parameters  also used for optimising idle mode cell reselection parameters  UE sends Radio Link Failure (RLF) measurement report to eNB where UE did re‐establishment  Optimised for Rel‐10 to use also ConnectionRequest too early handover Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 37
    • MRO (Rel‐9, ext Rel‐10) OAM monitor KPIs, alarms: config target: Nr of HO events Rate of failures related to  Nr of HO failures HO Nr of too early HO eNB RRM config examples: MRO Trigger Threshold Time‐to‐Trigger Hysteresis against Ping‐Pong Mobility Speed & Neighbour Param. Control Electric Antenna Tilt Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 38
    • MLB (Rel‐9) Mobility Load Balancing   Distribute cell load evenly among cells or   Transfer part of traffic to other cells so that radio resources remain highly  utilized   Optimisation of mobility parameters or handover actions  Also includes setting of cell reselection mode for idle mode balancing Load Reporting  the radio resource usage (UL / DL PRB usage)  HW and TNL load indicator (UL/DL load: low, mid, high, overload)  a cell capacity class indicator and capacity value (UL / DL) PRB  = Physical Resource BlockTNL = Transport Network LayerHW = HardwareUL = uplinkDL = DownlinkRAB = Radio Access Bearer (next slide) Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 39
    • MLB – Active Mode LB OAM config target: monitor KPIs, alarms: ‐ RAB setup failure rate due to load Nr RAB setup failure due to load ‐ Rate of failures related to HO Total nr of RAB setup failureTarget  Serving eNB RRM configeNB LOAD INFO HO Trigger MOBILITY CHANGE MLB ‐/+ 10dB   target cell is informed (incr/reduce   proposed source cell  time until HO  decision) change Mobility  proposal for target cell  change Control Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 40
    • RACH optimisation (Rel 9)  Optimises the (P)RACH configuration access to internal  measurements and access to feedback from UEs (via RRC) and  from other (H)eNBs  The setting of RACH parameters that can be optimized are:   RACH configuration (resource unit allocation), preamble groups split,  backoff, power control  UEs which receive UEInformationRequest shall feedback: Number of RACH preambles sent until the successful RACH  completion (indication of quality of link) Contention resolution failure (indication of cell load)  X2 allows to exchange RACH config between eNBs  Rel 10 OAM policy targets: Access Probability and Access Delay  Probability Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 41
    • Min. Drive Tests (R10 procedure)  Performs logging of available measurements together with  location and time for logged measurement configured UEs  Types: Immediate and logged measurements  Immediate measurements (UE optional FFS) Reuses normal measurements with addition of location  Enhancement of RLF Report to include location  Idle mode logged measurements (UE optional) Input: duration, interval, cell ids and/or tracking areas Time, Location, Cell id, scell/ncell RSRP/Q  Add. eNB meas: eNB RIP and CQI under disc, + PHR and UL SINR  MDT activation via OAM per cell/region (not reused at HO)  S1 UE specific trace activation (can be cont. on HO) Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 42
    • Coverage and Capacity Opt (Rel‐10) Coverage definition “coverage hole” (should cover UL also) unsuccessful RX of DL control channels and signalling radio bearers different control channels have to be optimised jointly “weak coverage”: cell‐edge users, minimum service rate  not reached Types of coverage holes other RATs/no radio, coverage too small/too large CCO detection using MDT/MRO  Inputs: UE measurements, Performance measurements,  alarms  Outputs: power control, antenna tilt, azimuth  Capacity & Coverage improvements Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 43
    • Energy Saving  Optimise energy consumption: a cell providing additional capacity can be  switched off when its capacity is no longer needed and to be re‐activated  when needed  The decision typically based on cell load information  Peer eNBs are about the switch‐off over the X2 interface (eNB  Configuration Update procedure)  Informed eNBs keep the cell config when a cell is off and may request re‐ activation if needed (X2: Cell Activation procedure)  How to select to correct cell to switch‐on?  The operators can configure ES function:  enable/disable ES  OAM policies for switch‐off and reactivation  open   interRAT, overlaid inter‐eNB savings  solutions to capacity limited scenario of inter‐eNB energy saving  ES in network sharing Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 44
    • 5. ConclusionsCopyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 45
    • SON Conclusions Benefits of SON:   reduction of human intervention  real‐time optimization of network  significant CAPEX & OPEX savings! NGMN & 3GPP:   important SON features standardised from R8‐R11  focus shifting from auto‐planning & self‐configuration towards self‐optimization and self‐healing  most important SON features have been discussed in this presentation  whereas concrete embodiments of SON comes later today Copyright © 2009  BeFEMTO– Broadband Evolved FEMTO Network. All Rights reserved 46