Aircom Nominal Planning for UMTS

Commercial-in-Confidence

Nominal Planning for UMTSNominal Planning for UMTS

Nominal Planning for UMTS


ContentsContents• The site rollout process• The nominal plan• Using the nominal plan



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?



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


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



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.


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


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.


Example nominal plan for Jersey


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.



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.


Or


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.



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.


A

D

C B


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.


A3rd

D1st

C2ndB - Unsuitable


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.



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.


60º

60º

180º180º

300º

300º

Ant 1

Ant 2

Ant 5

Ant 4

Ant 6

Ant 3


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.



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



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



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



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.



Create Site TemplatesCreate Site Templates• Create default nominal sites

! either an omni site.! and/or a sector site.

• 3 sector parameters listed here.


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.


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.



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.



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.



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.



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.


Create Traffic Raster

Capture Traffic

Evaluate Each Cells Required Capacity

Re-Engineer Network (if required)


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



Spread Voice TrafficSpread Voice Traffic• Spread the traffic on the voice

terminal type over the island.



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.



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



Spread Data TrafficSpread Data Traffic• Spread the traffic on the data

terminal type over the island.



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.



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



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


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.


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


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


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


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.

Aircom Nominal Planning for UMTS

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