3G aspects of optimization*
Study of Self-Optimization of Neighbor Cell Listing for eNodeB in Long Term Evolution (LTE)
Hanan Naeem
Thesis Worker
Ericsson Finland
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Study of Self-Optimization of Neighbor Cell Listing for eNodeB in Long Term Evolution (LTE)
Author: Hanan M. Naeem
Supervisor: Prof. Riku Jäntti
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LTE - Long Term Evolution
Study and work done by 3GPP to specify the long term evolution of the 3G radio part referred as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network)
SAE - System Architecture Evolution
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Cell-edge data rates 2-3 times that of Rel-6 HSPA
Low delay/latency
Channel set-up: Less than 100 ms
High spectral efficiency
Spectrum flexibility
Support for FDD, Half-duplex FDD and TDD Modes
Cost-effective migration from current/future 3G systems
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Single eNodeB encompassing all major functionalities
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IP based Core network
EPC to be based on a single-node concept (GW) with all necessary functions encompassed in one node except the HSS (Home Subscriber Server)
MME (Mobility Management Entity) responsible for authentication of the user by interacting with HSS, bearer activation and deactivation and GW assignment during handovers
Anchors all 3GPP and non-3GPP technologies like GSM,HSPA, WiMax
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Thorough study of the concept of self-configuration & self-optimization.
Neighbor Cell List (NCL) self-optimization in cellular networks
Suggesting a possible NCL self-optimization algorithm
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Personalization
Autonomic computing is often referred to as self-CHOP (Self-Configuration, -Healing, - Optimization, and -Protection)
Automatic: Autonomic system must be able to self control and automatically configure or reconfigure
Adaptive: An autonomic system must be sensitive and be able to alter its course of action based on the situations confronted based on defined policies
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Self-Configuration
Configuration of a new node or a radio base station deployed or installed in an already working cellular network
Node undergoes self-automated management tasks to adjust to the actual confronted environment
Automated management tasks take place in pre-operational state of the node before entering the operational state
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Self-Configuration Features
Decentralization: Nodes or entities interact and communicate with each other in a localized manner
Adaptability: Ability to adapt in parallel with user density and traffic patterns
Survivability: Capability of a system to fulfill its mission, in a timely manner, in the presence of attacks, failures, or accidents
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Continuation of self-configuration
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Major Self-Optimization Tasks
Cell Identity Management:
Due to the availability of limited number of 504 physical-layer cell identities, Cell Identity Management is critical to avoid conflicts
Neighbor Cell Management:
Self-optimization enables each eNodeB manages a list of immediate neighboring eNodeBs in the network
Power Tuning:
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Graph associated to each layer functionality
Range based approach
Neighbor cells detected within a certain range of the candidate cell are regarded as potential neighbors
Overlapping identification finalizes the neighbor cell
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Same as range based technique
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Self-configuration phase has been completed successfully.
Sectorization is observed throughout E-UTRAN
There are no coverage gaps after self-configuration
Self-configuration phase has allocated each eNodeB cell with a calculated value of r
All cell IDs, corresponding IPs and assigned parameter ‘r’ to each cell are stored in a central database.
UE triggers measurement reports once a new potential neighbor comes across. This information is sent to the eNodeB for NCL calculations.
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Geographical coordinates used for angular calculations
Measurements done with respect to antenna main lobe direction
Overlapping detected based on different UEs in the field and measurement reports sent
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Cell Deletion From NCL
Unwanted and obsolete neighbors are to be deleted to keep the NCL updated
Conditions for deletion:
Σi [Φi] = , i=1,2, … N
Identify which cells are not been assigned any angle during the iteration process
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Conclusions
LTE is expected to meet most of the current market requirements
Self-managing processes would make this communications technology more robust, scalable and adaptable
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