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Initial parameter planningMODULE 12
PRE-PLANNING
DETAILED PLANNING
Propagation measurementsCoverage prediction
Load estimationTraffic distributionPlanned Service and QoS definition
Post-launch optimisation
Measurement surveys
Statistical performance analysis
Quality Efficiency Availability
POST-PLANNING
Coverage and Capacity Planning
Dimensioning
Requirements and strategy for coverage, capacity and quality
PER SERVICE
Network configuration
Pre-launch optimisation
Measurements
ConfigurationPlanningConfigurationPlanning
Node-B Configuration
Antenna line configuration
Power budget
PER SERVICE
Site selection and planning
Site acquisition
Parameter Planning
Area/cell specific
Handover strategies
Other RRM
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Dimensioning process
Objectives
After this module the participant shall be able to:-
•Understand main principles of scrambling code
planning
•Understand main principles of neighbour planning in
3G
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Module Contents
• Scrambling code planning
• Neighbour planning principles
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Module Contents
• Scrambling code planning
• Neighbour planning principles
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Scrambling code
• Each cell within the radio network plan have to be assigned a primary scrambling code
• The 512 downlink primary scrambling codes are organised into 64 groups of 8
• Group 0 = SC 0…7
• Group 1 = SC 8…15
• …
• Group 63 = SC 504…511
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Scrambling code planning rules
• Main target to achieve sufficient isolation between cells which are assigned the same scrambling code
• Ensure that a UE never simultaneously receives the same scrambling code from more than a single cell
• UE never receives a scrambling code from one cell while it is expecting to receive the same scrambling code from second cell
• SHO failures
• Scrambling code planning may require co-ordination at international borders
• Scrambling code planning can be completed independently for each RF carrier
• An important part of scrambling code planning is to perform checks that neighbour lists do not include duplicate scrambling codes
• Measured (neighbour) cell is identified by the scrambling code only
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Scrambling code planning strategies
• Scrambling code planning strategies• Maximise the number of neighbours belonging to the same code group
• Maximise the number of neighbours belonging to different code groups
• Possible effect on cell synchronisation procedure• During cell selection, cell re-selection and soft handover
• The difference is likely to be dependant upon the UE implementation
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Example – SC plan for ROC configuration
• Strategy: Maximise the number of neighbours belonging to the same code group• When upgrade ROC Node B CEC Node B
• Additional four scrambling codes from each group• Two SCs for future expansion
Group 0
Group 2
Group 3
Group 4
Group 1
sc32
sc33
sc17
sc16
sc25
sc24
sc8
sc9
sc0sc1
Group 0
Group 2
Group 3
Group 4
Group 1
sc32
sc33
sc17
sc16
sc25
sc24
sc8
sc9
sc0sc1
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Scrambling code planning methods
• Using a radio network planning tool• NetAct Planner is able to plan scrambling codes according to a specific
strategy
• Using a ‘home-made’ tool
• Manually• For small areas (e.g. less tan 30 sites)
• Consideration should be given to moving the scrambling code plan to and from the live network
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Module Contents
• Scrambling code planning
• Neighbour planning principles• 3G Intra-frequency neighbour list planning
• 3G Inter-frequency neighbour list planning
• 2G neighbour list planning
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Neighbour planning and planning process
• In general it is recognised that high quality neighbour lists are critical to the performance of the network
• It is often assumed that neighbour lists will be refined during pre-launch or post-launch optimisation
• Initial neighbour list planning does not have to be very accurate
• Impact upon pre-launch optimisation have to be recognised
• Pre-launch optimisation is usually limited to a specific drive route• Neighbours which are required away from the drive route must be identified
during the planning process
• It is difficult to generate ideal neighbour lists during the neighbour list planning because of differences between predicted and actual propagation
• Pre-launch or post-launch optimisation required
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Module Contents
• Scrambling code planning
• Neighbour planning principles• 3G Intra-frequency neighbour list planning
• 3G Inter-frequency neighbour list planning
• 2G neighbour list planning
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3G Intra-frequency neighbour list
• 3G intra-frequency neighbour list planning is absolutely critical to network performance
• 3G intra-frequency neighbours are used for intra-frequency cell re-selection, softer handover, soft handover and intra-frequency hard handover
• Excessive neighbours increase the UE measurement time and may lead to important neighbours being deleted during soft handover
• Specification allows the network to specify a maximum of 32 intra-frequency cells for the UE to measure
• Serving cell + 31 Intra-frequency neighbours when not in soft handover
• 2-3 serving cells + 30-29 neighbours in soft handover
• Missing neighbours result in unnecessarily poor signal to noise ratios
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Neighbour planning tools
• Neighbour list planning can be completed using • Planning tool, e.g. Netact Planner which utilises
• Propagation predictions• Minimum CPICH Ec/Io requirements• Inter-cell interference• Maximum allowed neighbour list size
• A ‘home-made’ tool• Make use of distance and antenna azimuth rather than path loss
• Using the 2G neighbour plan • In networks which are primarily co-sited with existing 2G sites
• Manually• Small networks (e.g. less than 30 sites)
• Intra-frequency neighbour lists should always be generated such that every neighbour relationship is bi-directional
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Module Contents
• Scrambling code planning
• Neighbour planning principles• 3G Intra-frequency neighbour list planning
• 3G Inter-frequency neighbour list planning
• 2G neighbour list planning
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3G Inter-frequency neighbour list
• Inter-frequency neighbours are used for inter-frequency cell re-selection and inter-frequency handover.
• The Nokia RNC allows a maximum of 48 inter-frequency neighbours to be defined with a maximum of 32 on any one RF carrier.
• The Nokia RNC instructs the UE to measure neighbours from one RF carrier at a time for inter-frequency hard handover.
• Missing neighbours result in potentially failed inter-frequency hard handovers and cell re-selections
• Do not generate the high levels of interference which are associated with missing intra-frequency neighbours
• Excessive neighbours increase the UE measurement time and may lead to important neighbours being deleted during soft handover.
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3G Inter-frequency neighbour planning
• Same tools can be used as with intra-frequency neighbour planning
• Inter-frequency neighbour plan can be based upon the existing intra-frequency neighbour plan
• If the second RF carrier is being introduced subsequent to network launch
• The intra-frequency neighbour plan should have already been tuned during pre-launch and post-launch optimisation
• The second or third RF carrier is typically introduced at traffic hotspots• Part of the capacity upgrade process
• Upgrading a relatively small number of sites, or small clusters of sites
• The inter-frequency neighbour lists can be generated manually from the existing intra-frequency neighbour lists
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Module Contents
• Scrambling code planning
• Neighbour planning principles• 3G Intra-frequency neighbour list planning
• 3G Inter-frequency neighbour list planning
• 2G neighbour list planning
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2G neighbour list
• GSM neighbours are used for inter-system cell re-selection and inter-system handover.
• 3GPP specifications and the Nokia RNC allow a maximum of 32 inter-system neighbours to be defined
• Missing neighbours result in potentially failed inter-system handovers and cell re-selections
• Do not generate the high levels of interference which are associated with missing intra-frequency neighbours
• Excessive number of neighbours increase the UE measurement time and may lead to important neighbours being deleted during soft handover
• If an operator has both GSM900 and DCS1800 networks then it is possible to define inter-system neighbours only for the GSM900 layer or only for the DCS1800 layer
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2G neighbour list planning
• Inter-system neighbour list planning can be completed using a planning tool or using a ‘home-made’ tool
• UE requires only one good 2G neighbour in each location of the cell coverage
• If 3G sites are co-sited with 2G sites then GSM neighbour lists configured within the RNC can be based upon those configured within the BSC
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Module 12 – Initial parameter planning
Summary
•Main target of the scrambling code planning is to
achieve sufficient isolation between cells which are
assigned the same scrambling code
•High quality neighbour lists are critical to the
performance of the network