Download - Aircom Nominal Planning for UMTS
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Nominal Planning for UMTSNominal Planning for UMTS
Nominal Planning for UMTS
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ContentsContents• The site rollout process• The nominal plan• Using the nominal plan
Nominal Planning for UMTS
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Session AimsSession Aims• This session answers the following questions:
! What is a nominal plan?! How does the nominal plan fit into the network rollout process?! How is a nominal plan created?! How is a nominal plan used?
Nominal Planning for UMTS
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What is a nominal plan?What is a nominal plan?• A nominal plan is initially a
hypothetical wireless network.• The nominal plan is the
starting point for the cell rollout process and will evolve into the final network design.
• As physical sites are identified and acquired, the nominal plan is amended.
Nominal Plan
Final Network Design
Rollout process
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Simplified Network Planning FlowchartSimplified Network Planning Flowchart
Create nominal plan
Define search areas
Site selection
Detailed site design
Site acquisition
Initial network dimensioning
Identify site options
Site construction
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Initial Network DimensioningInitial Network Dimensioning• Spreadsheet based analysis.• Used in the license application.• Identifies the approximate
number of sites required.• Identifies the approximate site
radii required for:! Urban/Suburban/Rural areas! Voice/Data services
• Used as a major input to the nominal plan.
Nominal Planning for UMTS
Urban Suburban RuralVoice 1.8 km 3.1 km
�����������������������������������������
�����������������������������������������
�����������������������������������������4.0 km
��������������������������������������������
64 kb/s 1.6 km������������������������������������������
������������������������������������������2.7 km 3.5 km384 kb/s
������������������������������������������
������������������������������������������
������������������������������������������1.4 km 2.4 km 3.2 km
Typical cell radii estimates
Maximum range to support all services
Service not supported in this environment
Service supported
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Create Nominal PlanCreate Nominal Plan• Position a hexagonal grid of
sites over the desired coverage area.
• The radius of each hexagon can be determined from the previous slide.
• The capacity of the network can then be analyzed to detect:
! Hot spots that require cell splits.! Under used cells that could be
removed from the plan.
Nominal Planning for UMTS
Example nominal plan for Jersey
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Define Search AreasDefine Search Areas• The sites in a nominal plan are only imaginary.• To become a real network, physical sites are required.• A suitable physical site must be found for each nominal site.• A suitable physical site must amongst other things:
! Give adequate radio coverage.! Have connectivity into the transmission network.! Be aesthetically and politically acceptable to the local community.! Have power nearby, good access and a co-operative owner.
• A survey of each nominal site is normally carried out to identify possible site options which meet the above criteria.
Nominal Planning for UMTS
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Define Search AreasDefine Search Areas• Guidelines have to be given to the surveyor so the options give
appropriate radio coverage.• The guideline is given in the form of a search area. Could be:
! Radius from the nominal site.! One or more polygons following height contours.
Nominal Planning for UMTS
Or
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Identify Site OptionsIdentify Site Options• Surveyor visits each search area and identifies potential site options.• The first sites to be considered should be
! Existing radio sites.! Sites offered from major site owners (MSO) E.g. Utilities & Railways.
• All options should meet certain criteria to ensure that they are! Technically acceptable.! Buildable
• A good idea to consult with the planning/zoning authority during the survey.
• Good training of surveyors will save time later in the build process.
Nominal Planning for UMTS
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Identify Site OptionsIdentify Site Options• The surveyor will prepare a
report listing the options.• Report will include:
! Accurate grid reference.! Accurate height of structures
or available antenna windows.! Photographs of the site.! 360º panoramic photos from
site or if obstructed from nearby location/structure.
Nominal Planning for UMTS
A
D
C B
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Site SelectionSite Selection• Normally a desk study.• Evaluate radio coverage and
transmission. ! Quickly eliminate unsuitable
options.! Rank the remaining sites in
order of preference.
• Nominate a preferred option and possibly a backup option.
Nominal Planning for UMTS
A3rd
D1st
C2ndB - Unsuitable
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Site AcquisitionSite Acquisition• Run more than one site simultaneously.• Negotiate with site owners.• Prepare drawings.• Draw up leases.• Apply for planning permissions.• Apply for power wayleaves.• As soon as one option is ready to proceed
! Sign the lease! Abandon the alternative! Enter site into building program.
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Detailed Site DesignDetailed Site Design• Prior to commencement of
construction work, a detailed site design is required.
• Includes! Antenna and feeder
requirements.! Antenna azimuths and tilts.! Equipment capacity
requirements
• Can’t be completed in isolation. Must take into account other sites.
Nominal Planning for UMTS
60º
60º
180º180º
300º
300º
Ant 1
Ant 2
Ant 5
Ant 4
Ant 6
Ant 3
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Creating a Nominal PlanCreating a Nominal Plan• At the start of the cell rollout program, the nominal plan is
only a rough outline of the network.• Static calculations will give adequate results at this stage. • Static simulations could be used, but the time taken to
analyze the entire network would be prohibitive.• It is more appropriate to analyze the nominal plan with
ASSET rather than 3G at this stage.
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Setting up ASSET for Nominal PlanningSetting up ASSET for Nominal Planning
Import suitable antenna patterns
Create UMTS cell layer
Create a UMTS propagation model
Create UMTS site templates
Nominal Planning for UMTS
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Create a UMTS Propagation ModelCreate a UMTS Propagation Model• In a real network rollout one of
the first tasks of the radio engineers would be to calibrate a UMTS propagation model.
• For the purposes of the following sections we will assume that this has been completed.
• Set up a propagation model with the parameters described here.
Parameter Setting Clutter Type OffsetModel Type Standard Macrocell Unclassified 0Frequency 2.2 Urban 10
Mobile Rx Height 1.5 Suburban Residential 5Effective Earth Radius 8491 Village 3
K1 143 Isolated Dwellings 2K2 42 Open Rural 1K3 -2.55 Woodland Forest 7K4 0 Park Recreational 2K5 -13.82 Industry 5K6 -6.55 Water 0K7 0.8 Airport 1
Eff. Ant. Height Relative Open in urban 5Diffraction Bullington Agricultural land 1
Merge knife edges 0 Pylons 1Sea 0Rivers 0
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Import Antenna PatternImport Antenna Pattern• Import the antenna patterns
supplied by the manufacturers.• For the purpose of this exercise
several antenna patterns have been supplied.
! An Omni! An 85º Sector
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Create Coverage Schema & Cell LayerCreate Coverage Schema & Cell Layer• The only parameters that are
necessary to set on the cell layer are the signal thresholds and the coverage schema.
• These are derived from the link budgets used in the network dimensioning.
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Create Site TemplatesCreate Site Templates• Create default nominal sites
! either an omni site.! and/or a sector site.
• 3 sector parameters listed here.
Nominal Planning for UMTS
Level Tab Field SettingSite General Hex Radius #1Cell General Model UMTSCell Cell Config Antenna 85 XPCell Cell Config Downtilt 4Cell Cell Config Height 20Cell Cell Config Azimuth #2
UMTS cell layer Antenna/TRX PA output 33
#1 Will depend on area type egUrban/Suburban/Rural
#2 Typically either 0º, 120º, 240ºor 60º, 180º, 300º.
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Creating a Nominal PlanCreating a Nominal Plan• From the link budgets, identify
the cell radius for each environment to be planned.
• Create a UMTS site template• For each environment, position
a hexagonal grid of sites with the appropriate cell radii over the target coverage area.
Nominal Planning for UMTS
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Locating Urban Nominal SitesLocating Urban Nominal Sites• Define mid hexagon radius as
1400m and select in the site template.
• Position a grid of sufficient sites to cover the urban areas.
Nominal Planning for UMTS
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Locating Rural Nominal SitesLocating Rural Nominal Sites• Define mid hexagon radius as
4000m and select in the site template.
• Position a grid of sufficient sites to cover the rural areas.
Nominal Planning for UMTS
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Evaluate Nominal Network CoverageEvaluate Nominal Network Coverage• Run a coverage array for the
nominal network.• Check that the coverage is in
line with your expectations.! The coverage will never exactly
match your hexagon radii.! If coverage is significantly better
or worse than anticipated review cell radius calculations and hexagon radii.
Nominal Planning for UMTS
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Evaluate Nominal Network CapacityEvaluate Nominal Network Capacity• Create a traffic raster for each
service.! Create a terminal type for each
service.! Spread traffic for each terminal
type to simulate users.
• Analyze how much traffic each cell will pick up (capture).
• Evaluate if each cell has sufficient capacity.
Nominal Planning for UMTS
Create Traffic Raster
Capture Traffic
Evaluate Each Cells Required Capacity
Re-Engineer Network (if required)
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Create Terminal TypesCreate Terminal Types• Create a circuit switched
terminal type for each service.• Allocate traffic to simulate
users.! Voice = 200 Erlangs! 384 kb/s = 100 Erlangs
(simulating 100 terminals)
Clutter Type WeightUnclassified 0
Urban 500Suburban Residential 20
Village 10Isolated Dwellings 1
Open Rural 1Woodland Forest 2Park Recreational 5
Industry 10Water 0Airport 5
Open in urban 30Agricultural land 1
Pylons 1Sea 0
Rivers 0
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Spread Voice TrafficSpread Voice Traffic• Spread the traffic on the voice
terminal type over the island.
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Create Coverage Array (Voice)Create Coverage Array (Voice)• Set the minimum service level
in the Array Settings window to match the minimum threshold for speech services.
! i.e. -114dBm
• Create coverage array as usual.
Nominal Planning for UMTS
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Analyze Voice TrafficAnalyze Voice Traffic• Use the traffic analysis tool to
estimate the voice traffic per cell.
Cell: CS Traffic(E)Site0A: 1.27874Site0B: 18.989Site0C: 2.64128Site1A: 18.1042Site1B: 0.099755Site1C: 1.71587Site2A: 2.13376Site2B: 1.58312Site2C: 105.062Site3A: 11.8475Site3B: 2.43671Site3C: 12.1231Site4A: 2.06883Site4B: 1.76368Site4C: 1.87409Site5A: 1.58884Site5B: 3.31571Site5C: 3.13637Site6A: 1.81907Site6B: 3.5485
Nominal Planning for UMTS
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Spread Data TrafficSpread Data Traffic• Spread the traffic on the data
terminal type over the island.
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Create Coverage Array (Data)Create Coverage Array (Data)• Set the minimum service level
in the Array Settings window to match the minimum threshold for data services.
! i.e. -96dBm
• Create coverage array as usual.
Nominal Planning for UMTS
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Analyze Data TrafficAnalyze Data Traffic• Use the traffic analysis tool to
estimate the voice traffic per cell.
Cell: Packet usersSite0A: 0.617848Site0B: 9.13428Site0C: 1.23677Site1A: 9.05208Site1B: 0.0498775Site1C: 0.769083Site2A: 0.732088Site2B: 0.687448Site2C: 52.4403Site3A: 5.71852Site3B: 0.963885Site3C: 5.90523Site4A: 0.496473Site4B: 0.396895Site4C: 0.889275Site5A: 0.337783Site5B: 0.733785Site5C: 0.781533Site6A: 0.754625Site6B: 1.74732Site6C: 1.42162
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Evaluating Traffic Requirements (1)Evaluating Traffic Requirements (1)Nominal Planning for UMTS
Real time non-controllable load
Spare capacity for which can be allocated to non real time applications
Peak traffic
Load
Time
Average circuit switched traffic
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Evaluating Traffic Requirements (2)Evaluating Traffic Requirements (2)• To evaluate the cell capacity
! First assume that the packet data can be scheduled to fill the spare real time capacity.
! When all the spare real time capacity has been exhausted we mustconvert the remaining capacity to 12.2kb/s voice equivalent circuits.
! It is now possible to estimate whether the cells capacity has been exceeded.
• Assume that a cell with a capacity of 60 12.2kb/s voice circuitscaptures:
! 1.58 Erlangs of voice traffic.! 0.69 384kb/s data users.
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Evaluating Traffic Requirements (3)Evaluating Traffic Requirements (3)Captured circuit switched Traffic = 1.58 Erlangs
Erlang B Formula (2% GOS)
5 circuits required
5 Erlangs
1.58 Erlangs
Offered packet data
= 0.69 x 384 = 263.98 kb/s
Nominal Planning for UMTS
Average capacity available for packet data
= 5 - 1.58 = 3.42 Erlangs
or 3.42 x 12.2 = 41.69 kb/s
Extra capacity required for packet data
= 263.98 - 41.69 = 222.29 kb/s
or 222.29 = 19 voice equivalent circuits12.2
Total voice equivalent circuits required
= 5 + 19 = 24
3.42 Erlangs
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Evaluating Traffic Requirements (4)Evaluating Traffic Requirements (4)Nominal Planning for UMTS
Voice (erlangs offered)
Voice (circuits required)
Voice equivalent
circuits available
for packet data
Data rate available
for packet data
(kb/s)
No of 384 kb/s
packet data users
Data rate required
for packet data
(kb/s)
Extra capacity required
for packet data
(kb/s)
Extra voice
equivalent circuits required
for packet data
Total voice
equivalent circuits required
OVERLOAD STATUS
Site0A: 1.27874 5 3.72 45.40 0.62 237.25 191.85 16 21 OKSite0B: 18.989 27 8.01 97.73 9.13 3507.56 3409.83 280 307 OVERLOADSite0C: 2.64128 7 4.36 53.18 1.24 474.92 421.74 35 42 OKSite1A: 18.1042 26 7.90 96.33 9.05 3476.00 3379.67 278 304 OVERLOADSite1B: 0.099755 2 1.90 23.18 0.05 19.15 0.00 0 2 OKSite1C: 1.71587 6 4.28 52.27 0.77 295.33 243.06 20 26 OKSite2A: 2.13376 6 3.87 47.17 0.73 281.12 233.95 20 26 OKSite2B: 1.58312 5 3.42 41.69 0.69 263.98 222.29 19 24 OKSite2C: 105.062 118 12.94 157.84 52.44 20137.08 19979.23 1638 1756 OVERLOADSite3A: 11.8475 19 7.15 87.26 5.72 2195.91 2108.65 173 192 OVERLOADSite3B: 2.43671 7 4.56 55.67 0.96 370.13 314.46 26 33 OKSite3C: 12.1231 19 6.88 83.90 5.91 2267.61 2183.71 179 198 OVERLOADSite4A: 2.06883 6 3.93 47.96 0.50 190.65 142.69 12 18 OKSite4B: 1.76368 6 4.24 51.68 0.40 152.41 100.72 9 15 OKSite4C: 1.87409 6 4.13 50.34 0.89 341.48 291.15 24 30 OKSite5A: 1.58884 5 3.41 41.62 0.34 129.71 88.09 8 13 OKSite5B: 3.31571 8 4.68 57.15 0.73 281.77 224.63 19 27 OKSite5C: 3.13637 8 4.86 59.34 0.78 300.11 240.77 20 28 OKSite6A: 1.81907 6 4.18 51.01 0.75 289.78 238.77 20 26 OKSite6B: 3.5485 8 4.45 54.31 1.75 670.97 616.66 51 59 OKSite6C: 2.84358 7 4.16 50.71 1.42 545.90 495.19 41 48 OK
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Evaluating Traffic Requirements (5)Evaluating Traffic Requirements (5)• From the previous slide
! Five cells are predicted as being overloaded.! One cell if close to being overloaded.
• All six cells need to be split for zero congestion.! Any congested omni sites should be sectored.! Sectored sites need to be offloaded onto new cells.
• After modifying the nominal plan, repeat the capacity analysis to ensure that the network is properly dimensioned.