• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
SON in LTE - additional materials
 

SON in LTE - additional materials

on

  • 687 views

Here are some additional materials from tutorial entitled 'SON in LTE' delivered during the event ‘Lunch with LTE’ in November 2013 in Warsaw, Poland. ...

Here are some additional materials from tutorial entitled 'SON in LTE' delivered during the event ‘Lunch with LTE’ in November 2013 in Warsaw, Poland.

If you are interested in attending top in class LTE/LTE-Advanced courses, please have a look http://is-wirelesstraining.com/course-map-2 or contact us directly: info@is-wirelesstraining.com.

Statistics

Views

Total Views
687
Views on SlideShare
638
Embed Views
49

Actions

Likes
0
Downloads
94
Comments
0

1 Embed 49

http://4g-university.com 49

Accessibility

Categories

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    SON in LTE - additional materials SON in LTE - additional materials Presentation Transcript

    • LTE SON as a concept for NW automation LTE SON podejściem do automatyzacji działania sieci
    • LTE SON Outline 1. SON Introduction 2. Self-Configuration Algorithms (PCI, ANR) 3. Self-Optimization Algorithms (ICIC, ESM) 4. SON Coordinaton Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • SON Introduction Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • SON Introduction SON Concept – Drivers for SON PRB conf HO thresh Increasing complexity of networks • Multitude / growing number of parameters with interdependencies • Multitude of RRM algorithms working at different time scales TimeToTrig Hysteresis AC AC thresh PSched Heterogeneous Network to be cooperatively managed • Macro/Micro/Pico/Femto cells and Relays cdma 2000 Overlaying multiple networks for a single operator • 2G/3G/LTE/WiFi LTE WiFi Core GSM UMTS Higher operational frequencies • Increase number of cells required / higher NW cost High performance required • Growing number of BW hungry services • Growing number of devices and change of device character (M2M) Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • SON Introduction SON Concept – Evolution Path Towards Autonomous System 3. Predictive 2. Managed 1. Basic Approved OAM OAM Action Auto Algs Action Suggested change Meas Meas Collect & aggregate info from NEs into few consoles where required configs are initiated manually All NEs are managed independetly 4. Adaptive Automatic algs (e.g. SON) recommend actions based on gathered info. Actions need to be approved One time high level policy definition 5. Autonomic Adjust policy Approved Approved Adjust policy OAM Auto Algs Policy Suggested change Long term performance report System automatically takes action based on measurements controlled by low level policies set/adjusted by operator Copyright by IS-Wireless. All rights reserved. OAM Auto Algs Policy Suggested change Fully integrated system is dynamically managed based on business rules and policies www.is-wireless.com
    • SON Introduction SON Concept – Challenges for SON ”Although SON promises huge benefits towards having reliable and optimum mobile networks, the benefits come with challenges in making them reality” M. Marvangi (ICIMU 2011, Malaysia) Challenge Convince operators to change NW management • Redefinition of OAM/Planning/Optimization Procedures • Gain trust on automation – gradual introduction of SON SON Solution Requirement Flexible SON configuration: • Fully controlled SON • Partly controlled SON • Fully automatic SON Easy migration from non-SON to SON NW Resolve conflicts between different SON functions Assure that SON features taken from different vendors will cooperate Assure that SON solutions will operate in multi-RAT NW • E.g. single tilt change for LTE optimization might influence badly other RATs if single antenna used Copyright by IS-Wireless. All rights reserved. SON Cooperation / SON Coordinator Standardization Effort for multi-vendor and coordination Standardization Effort for InterRAT SON www.is-wireless.com
    • SON Introduction SON Within 3GPP Standardization (1/2) SON: set of Use Cases that govern the NW including: planning, setup & maintanence SON objective: minimization of manual changes of RAN configuration and optimization SON Self Configuration Self Optimization Self Healing Optimize powers HO params PRACH params Plug in Recovery actions Alarm Network RF failure eNB Configuration downloading eNB eNB restart eNB take over UEs eNB 3GPP approach for SON (3GPP TS 32.500): ”SON algorithms themselves will not be standarized in 3GPP” ”3GPP standarizes measurements, procedures and open interfaces to support SON” Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • SON Introduction SON Within 3GPP Standardization (2/2) Standard / Operator SON targets / policies Non-standard / Vendor dependent SON Framework SON algorithms Standard Settings, parameters Standard Nodes and interfaces Non-standard / Operator (counters / threshold / KPI) Standard eNB, UE measurements Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • SON Introduction Key Parts of SON SON supporting functions Copyright by IS-Wireless. All rights reserved. Main areas of SON www.is-wireless.com
    • Self-Configuration Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • Self-Configuration Self Configuration Procedure Example Self-Configuration (S-Conf): Process which brings a network element into service requiring minimal human operator intervention or none at all. Already deployed eNB New eNB 5. Auto X2 with neighbor setup eNB eNB O&M 3. Auto software and configuration download (e.g. PCIs, neighbors) 2. Get the IP address eNB 6. Configure the PCIs for cells 4. Autosetup the S1 connection 7. Set the neighbor cells (ANR) DHCP Server 1. Auto connect to backhaul Backhaul MME Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • Automated Configuration of PCI PCI Usage and PCI Assignment Criteria 504 PCIs To be distributed among cells PCI = 6 PCI = 3 PCI = 4 PCI = 1 Used at: • Synchronization (PSS/SSS) • Measurement reports • Handover requests • Cell reselection meas. • PHY signals (CRS, DRS) PCI = 2 PCI = 5 Criteria for PCI Assignment Collision- and confusion-free assignment Avoid reconfigurations Adaptability to different NW deployments .. but, PCI reuse is required (especially for HetNets) Applicability to initial and evolutionary deployment scenarios Specific PHY and operator policy constraints Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • Automated Configuration of PCI Collision and Confusion Free Possible Problems with PCI assignment Collision two neighbors have the same PCI PCI = 1 • • Collision free each two neighbors shall have different PCIs PCI = 1 PCI = 1 PCI = 2 UE is not able to differentiate between these two cells UE in connected mode can synchronize to the cell that it is not attached to Confusion two neighbors of a given (center) cell have the same PCI PCI = 1 • The assignment of PCI shall be PCI = 2 PCI = 1 Confusion free all neighbors of a given (center) cell shall have different PCI PCI = 1 PCI = 2 PCI = 3 If UE reports to cell 2 of strong cell 1 (left hand), the eNB can direct the user to right hand cell 1 in HO (which is not the reported neighbor) We may need a central assignment and reassignment the PCI to all eNBs (using e.g. graph coloring algorithm in RNP tool or a central node for assigning the IDs) Conflict avoidance approaches for distributed SON Listen on the radio interface (Listening module at eNB before setting PCI) UE assisted PCI detection (UE report all received PCIs, eNB assigns temporar PCI) Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • Automated Configuration of PCI Example Approach to Centralized PCI Assigment Usage of Graph Coloring Approach • • Use different colours for each node of the graph Use lowest number of different PCIs with collision / confussion free approach 2. Representation of the NW by graph • • 1. Example network layout Node – cell Edge – neighborhood relation to direct neighbor or neighbor of neighbor Neighbor of neighbor relation Considered Cell Neighbor of neighbor Considered Cell Direct neighbor relation Direct neighbor Approach: two connected nodes need to have different colours 4. Collision and confusion free PCI assignment PCI B PCI C PCI A PCI C Copyright by IS-Wireless. All rights reserved. 3. Coloured Graph PCI B www.is-wireless.com
    • Automatic Neighbor Relation Function Neighbor Relations Importance No ANR With ANR Succesful HO Measure Cell B and report Succesful HO Measure Cell B and report Cell B NR Table • Cell B • Cell Z NR Table • Cell B • Cell Z Cell A (serving) Cell C Cell A (serving) Cell C Cell C NRT update and HO control to cell C No Cell C measurement RLF and re-est in cell C Copyright by IS-Wireless. All rights reserved. Cell B Cell C discovery / measurement and report Succesful HO www.is-wireless.com
    • Automatic Neighbor Relation Function UE Based LTE Cell Discovery (LTE ANR) Core 6. TNL address of eNB with ECGI = 30 • • PCI = 1 EGCI = 20 • • PCI = 2 EGCI = 30 2. RRC Meas. Rep. (PCI = 2) 5. Report (ECGI = 30) 3. Request to report ECGI for PCI = 2 4. Read BCCH (ECGI = 30) NR Table • PCI 10 • PCI 12 PCI 2 1. Measure signal (PCI = 2) eNB eNB PCI 1 7. New entry (upd. NRT) PCI 2 NR Table • PCI 11 • PCI 13 PCI 1 9. New entry (upd. NRT) 8. Establish X2 interface (X2 Setup) Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • Self-Optimization Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • Self-Optimization Self Optimization Algorithm (High Level View) Keep monitoring Monitor input data Analyse input data with optimization algorithms Yes UE measurements UE signalling (e.g. RLF) Cell global counters Meet the targets? No Apply optimization algorithm and parameter adaptation Execute corrective actions Fallback mechanism System state better after the corrective actions execution? Yes No Restore the system to the previous state (before the corrective actions were executed) One time self-optimization procedure ends Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • Inter-Cell Interference Coordination ICIC Scenarios ICIC goal: Control the inter-cell interference (possible for PUSCH, PDSCH, PUCCH) Downlink Uplink Useful signal Interference eNB measures interference UE measures interference and sends info to eNB over measurement reports • • • Static – parameters are not changed (PFR or full reuse 1) Semi dynamic – slow adaptations of resources and CEU/CCU threshold Dynamic ICIC scheme – frequent adjustments of parameters (requires a lot of X2 signalling) Example semi-dynamic scheme – Partial Frequency Reuse Power Power CEU CEU SON ICIC decides on: • • • CCU f Inner / outer zone threshold BW part for each zone Outer zone reuse scheme for neighbors BW f BW Inner zone Copyright by IS-Wireless. All rights reserved. CCU Outer zone www.is-wireless.com
    • Inter-Cell Interference Coordination Example ICIC Operation on UE Mobility Cell 1 Cell 2 Power Power 2 1 3 4 5 f f BW 1 BW 2 5 4 3 UE is scheduled to outer subband where cell 2 doesn’t transmit UE is scheduled to inner subband with low interference (due to large pathloss) from cell 1 UE is handed over from cell 1 to cell 2 UE is scheduled to inner subband with low interference (due to large pathloss) from cell 2 UE is scheduled to outer subband where cell 1 doesn’t transmit Useful signal Interference Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • Inter-Cell Interference Coordination Proactive vs Reactive Approaches Reactive approach I’ve measured interference at PRB x 1 I’ll adapt power levels of UEs to decrease interference 2 eNB • Proactive approach (Dynamic PFR/SFR) Using indicators of experienced interference (interference is present) Copyright by IS-Wireless. All rights reserved. 1 I’ll not use PRB x 2 eNB OI = per UL PRB report on experienced interference I’ll schedule UE at PRB x eNB • • eNB HII = bitmap of UL PRB – interference sensitivity RNTP = bitmap of DL PRB – power threshold exceeding Announcing scheduling decisions (requires a lot of signalling) www.is-wireless.com
    • Energy Saving Management Example Daily Traffic Profile 100 Load voice % of max capacity of cell Load data % of max capacity of cell RF output power % of max output power 90 80 70 [% ] 60 50 40 30 20 23-0 22-23 21-22 20-21 19-20 17-18 16-17 15-16 14-15 13-14 12-13 11-12 10-11 9-10 8-9 7-8 6-7 5-6 4-5 3-4 2-3 1-2 0 0-1 10 Hour Possiblity to switch off cell Copyright by IS-Wireless. All rights reserved. High traffic scenario www.is-wireless.com
    • Energy Saving Management ESM Introduction and Usage Scenario ESM goal: Cost savings and reduced environmental impact. Focused on automatic adaptations of offered capacity by NW to actual traffic demand at given point of time Example actions • • Radio solutions: • Not scheduling in certain subframes • Switch off some antennas to save power in MIMO modes • Adapt transmission power • Switch off some carrierrs NW solutions: • Switch off cells (e.g. for HeNBs, capacity booster Pico cells etc) Considered scenarios • • Cell overlaid use case • eNB can enter ES mode if there’s radio coverage from other system Capacity limited network use case • Coverage area of a group of eNBs is taken care by one of more of its eNBs while others go into ES state Example scenario – capacity booster / capacity limited NW Coverage based macro-cells and capacity based pico-cells No-ES Switch-off capacity-boosters when capacity is no longer needed No-ES No-ES No-ES No-ES No-ES High traffic situation (e.g. busy hour) Copyright by IS-Wireless. All rights reserved. No-ES ESaving ESaving (cap booster) ESaving ESaving ESaving EScompensate (macrocell) ESaving Low traffic situation (e.g. night hours) www.is-wireless.com
    • SON Coordinator Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • Interaction Between SON Use Cases Problems with Interactions Multiple SON use cases UE measurements SON Use Case 1 eNB measurements SON Use Case 2 SON Use Case 3 • Can alter the same parameter • Interact with each other • • Parameter 1 Can work against each other Performance depends on multiple use cases Parameter 2 SON coordination definition (3GPP TS 32.522): ”SON Coordination means preventing or resolving conflicts or negative influences between SON functions to make SON functions comply with operator policy” Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • Interacting Use Cases - Example Interactions Between Handover Parameter Optimization and Load Balancing Metric conflict Unsatisfied users Virtual load HO offset Hysteresis HO param optimization RLF ratio (HPIRLF) HO ping pong ratio (HPIHPP) TTT HO failure ratio (HPIHOF) SON algorithms Control parameters KPIs / metrics Weighted sum: HP = w1 * HPIHOF + w2 * HPIHPP + w3 * HPIRLF Load balancing Source: Socrates D5.9 Final report Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • Interacting Use Cases – Example SON Coordinator – Cooperative Use Case Example (HPO and LB) Conflict detection and resolution E.g. settings of metrics weights, setting assured virtual load Coordination policy selection Operator policy COO1 Alignment HPO priorty COO2 Requested LB priority changes COO3 Abnormal situation detect/solve SON Coordinator Collects and processes PM/FM/CM Autognostics Virtual load Load balancing HO offset RLF ratio Hysteresis HO param optimization HO ping pong ratio TTT HO failure ratio SON algorithms Control parameters KPIs / metrics Source: Socrates D5.9 Final report Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • Interacting Use Cases - Example HPO and LB Cooperative Use Case – Example Results Av. No of unsatisfied users (%) Call drop ratio (%) HO pingpong ratio (%) HO failure ratio (%) Performance (%) 30 25 20 15 10 5 0 No SON HPO LB HPO&LB HPO&LB& Coordinator Source: Socrates D5.9 Final report Copyright by IS-Wireless. All rights reserved. www.is-wireless.com
    • Thank you for your attention! Copyright by IS-Wireless. All rights reserved. www.is-wireless.com