Self Organizing Network in LTE. This covers different use cases.

1. Sachidananda Sahu

2.  Introduction
 Why SON
 SON In LTE
 Drivers for LTE SON
 LTE SON Features
 LTE SON Framework
 LTE SON Architecture
 Self Configuration Use Case
 PCI Planning Use Case
 ANR Use Case
 MRO Use Case
 Other LTE SON Features
 Conclusion
 References

3. Processes of self-organization literally create order out of disorder
~Francis Heylighen

4.  Self Organizational Network express itself that it organizes the network automatically and reduces
the manual intervention.
 SON is a collection of procedures or functions for automatic configuration, optimization,
diagnostication, and healing of networks.
 Things under consideration
 Material (Spectrum, Equipment, etc.) - With what things we will do the work.
 Human (Engineering time) - Who will do the work.

5.  The NGMN (Next Generation Mobile Networks Association) first published its SON requirements
in 2006.
 The concepts quickly picked up by 3GPP in 2008 and rolled into the LTE standardization activities.
 Starting with Release 8, 3GPP defines interfaces for SON built upon existing management
architecture.
 Successive 3GPP releases incorporates additional SON features tracking the expected network
evolution stages in time.
 Specification for SON and its use cases
 TS 36.300 : E-UTRAN Overall Description
 TR 32.821 : Study of SON related operation and OAM for home eNB.
 TR 32.500 : SON Concepts and Requirements
 TR 36.902 : Self Configuring and Self Optimizing Network use cases and solutions

6.  Reducing manual intervention or least possible human interaction.
 Atomization of repetitive process.
 Improve runtime operation/optimization based on real time data analysis.
 Improving user experience and network performance.
 Reduction of OPEX, CAPEX and complexity.
Network with out SON Capability Network with SON Capability

7.  SON Solution can be divided in to three categories
1 Self Configuration
2 Self Optimization
3 Self Healing
SON Features Proposed by NGMN

8. LTE SON Features …
1 Self Configuration
 Self-configuration mechanism is desirable during the pre-operational phases of network
elements such as network planning and deployment.
 Self Configuration Use Cases
 Plug & Play : IP Address allocation, Authentication, Software and Configuration Download from OAM, Establish connectivity with other nodes
 Planning radio parameters of a new eNB: Physical Cell ID automatic configuration, handover & cell selection thresholds, power settings, etc
 Planning transport parameters of a new eNB : SGW gateway nodes
 Planning connection for all neighbor nodes: Automatic Neighbor Relation (ANR)
 Self test

9. LTE SON Features …
2 Self Optimization
 Self-optimization mechanism is desirable during the operational stage so that network operators
get benefits of the dynamic optimization.
 Self Optimization Use Cases
 Neighbor cell list optimization
 Evaluation/addition/deletion of existing neighbor cells
 Intra/inter frequency and inter system neighbor cell list optimization
 Interference control
 Handover parameter optimization (MRO)
 Load balancing
 Energy savings
 RACH load optimization
 QoS related parameter optimization

10. LTE SON Features …
3 Self Healing
 Detects problem and solve or mitigate those to avoid user impact.
 Self Healing Use Cases
 cell outage detection and compensation : Antenna tilt and the cell transmit power
 self-recovery of network element (NE) software
 self-healing of board faults
 Self-diagnosis: create a model to diagnose, learning from past experiences.
 Self-healing: automatically start the corrective actions to solve the problem.
 Significantly reduce maintenance costs.

11. 3GPP Proposed SON Framework

12.  SON can be located as whole functionality block or even split in sub-functionality located in
different nodes.
 Localization of algorithm and control.
Centralized SON Distributed SON Hybrid SON

13.  Process where newly deployed nodes (eNBs) are configured by automatic installation procedures to get the
necessary basic configuration for system operation.
Self Configuration Procedure Flow

14.  Automatically configure the Physical Cell ID of a newly introduced cell and also change the PCI to
after detection of problem in PCI planning.
 Things to consider :
 Collison Free : The PCI of one cell should not be the same as those of his neighbor cells.
 Confusion Free : The PCI of the neighbor cells should not be the same.
PCI A PCI BPCI A PCI A
Collision Based Collision Free
PCI A PCI C
PCI B
PCI A PCI A
PCI B
Confusion Based Confusion Free

15.  PCI Planning Approach
 Listen on Radio Interface (NLM)
 UE assisted PCI detection
 X2 Message Based PCI detection
 3GPP Messages used for PCI Planning
 X2 Set Up Request
 X2 Set Up Response
 Measurement Report
 ENB Configuration Update
A Possible Solution

16.  It aims to set up the neighbor relation automatically as much as possible.
 ANR function relies on OAM and UE to report the neighbor cell information.
• OAM’s significance
• UE Measurement Report
ANR with help of UE Measurement

17.  A Neighbor cell Relation
• Source cell knows the ECGI/CGI and PCI of the target cell.
• Has an entry in the Neighbor Relation Table for the source cell identifying the target cell.
• Has the attributes in this Neighbor Relation Table entry defined, either by O&M or set to default values.
ANR Architecture Diagram

18.  Problem
 Manual setting of HO parameters in current 2G/3G systems is a time consuming task and it is also costly.
 Incorrect HO parameter setting negatively affect user experience.
 Solution
 Automatically adjusting the mobility parameters Trigger thresholds,Time to trigger, Hysteresis, NRT,
Antenna Remote Electrical Tilt etc
 Detecting the cause of Reduce Radio Link Failures and unnecessary handovers and decrease those counts.
 To enable adjustment of HO parameters , HO errors, reported by UE, can be notified to eNBs by backhaul
signaling.
 Too late handover
 Too early handover
 Handover to the wrong cell

19.  Too Late Handover
• If the UE mobility is faster than the HO parameter settings allow for.
• RLF in the source cell before the HO was initiated or during HO procedure.
• Terminal re-establishes in a different cell than the source

20.  Too Early handover
• RLF occurs a short time after the HO trigger to the target cell. The HO may or may not be
completely successful, depending on the over-the-air-messaging in the target cell.
• Terminal re-acquires the system in the source cell

21.  Wrong Cell handover
• RLF occurs a short time after the HO trigger to the target cell. The HO may or may not be
completely successful, depending on the over-the-air-messaging in the target cell.
• Terminal re-establishes in a different cell than the source or target.

22.  Mobility Load Balancing
 To balance the load between neighbor cells, capacity and handover parameters information are shared between eNBs
 MLB Functionality
 Load is measured for each cell in its monitoring eNB and information is exchanged over X2.
 An algorithm is applied to identify the need to distribute the load between two adjacent cells.
 Handover and/or cell reselection parameters are adjusted to enable the load balancing.

23.  Energy Saving & Interference Reduction
 Decreasing power consumption of network elements and reduce greenhouse emission.
 The ability of ENB to perform cell deactivation and reactivation based on cell load information and maintaining coverage, capacity
and quality of service.
 Interference reduction based on cell switch on/off which also increases capacity and quality.
 Based on load server information SON server takes decision.
3GPP Supported Messages

24.  Inter Cell Interference Coordination
 Problem
 DL Interference
 UL Interference
 Solution
 Avoid Use of same PRBs
 Co-ordinate use of PRBs
 RACH Optimization
 To reduce possible RACH (Random (Random Access Channel) Channel) resources collisions, so
configuration information is shared between eNBs.
 PRACH‐Configuration information is delivered by the X2 Setup and eNB Configuration Update messages.

25.  Reduction of human intervention.
 Real time optimization of network.
 Control in OPEX and CAPEX for operator.
 SON are flexible, adaptive, resilient, and scalable.
Merits of SON Operational Efficiency ~ Technology Graph

26.  TS 36.300 - Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Overall description
 TR 36.902 : Self Configuring and Self Optimizing Network use cases and solutions
 Self-Organizing Networks (SON) in 3GPP LTE Nomor Research
 The SOCRATES (Self-Optimisation and self-ConfiguRATion in wirelEss networkS) Project
 Benefits of Self-Organizing Networks (SON) for Mobile Operators Journal
 https://www.exploregate.com/
 https://www.sonlte.com/
 http://www.3gpp.org/

27. THANK YOU!