Aircom Nominal Planning for UMTS

Nominal Planning for UMTS


Commercial-in-Confidence


Contents • • •

The site rollout process The nominal plan Using the nominal plan



Session 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? •

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 Rollout process

Final Network Design



Simplified Network Planning Flowchart Initial network dimensioning Create nominal plan Define search areas Identify site options Site selection Site acquisition Detailed site design Site construction



Initial Network Dimensioning • Spreadsheet based analysis. • Used in the license application. • Identifies the approximate number of sites required.

• Identifies the approximate site radii required for:

Typical cell radii estimates Voice 64 kb/s 384 kb/s

Urban 1.8 km 1.6 km 1.4 km

Suburban 3.1 km 2.7 km 2.4 km

Rural 4.0 km 3.5 km 3.2 km

Service supported

!

Urban/Suburban/Rural areas

Maximum range to support all services

!

Voice/Data services

Service not supported in this environment

• Used as a major input to the nominal plan.



Create 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 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 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 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 Options • The surveyor will prepare a report listing the options.

• Report will include: ! !

! !

A

Accurate grid reference. Accurate height of structures or available antenna windows. Photographs of the site.

D C

B

360º panoramic photos from site or if obstructed from nearby location/structure.



Site 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

A3rd D1st C2nd

B - Unsuitable

and possibly a backup option.



Site 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 Design • Prior to commencement of

300º

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.

Ant 6

60º Ant 1

300º

60º

Ant 5

Ant 2 Ant 4 180º

Ant 3 180º

Must take into account other sites.



Creating 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.

•

It is more appropriate to analyze the nominal plan with ASSET rather than 3G at this stage.

Static simulations could be used, but the time taken to analyze the entire network would be prohibitive.



Setting up ASSET for Nominal Planning Create a UMTS propagation model Import suitable antenna patterns Create UMTS cell layer Create UMTS site templates



Create 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.

Parameter Model Type Frequency Mobile Rx Height Effective Earth Radius K1 K2 K3 K4 K5 K6 K7 Eff. Ant. Height Diffraction Merge knife edges

Setting Standard Macrocell 2.2 1.5 8491 143 42 -2.55 0 -13.82 -6.55 0.8 Relative Bullington 0

Clutter Type Unclassified Urban Suburban Residential Village Isolated Dwellings Open Rural Woodland Forest Park Recreational Industry Water Airport Open in urban Agricultural land Pylons Sea Rivers

Offset 0 10 5 3 2 1 7 2 5 0 1 5 1 1 0 0

• Set up a propagation model with the parameters described here.



Import 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 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 Templates • Create default nominal sites !

either an omni site.

!

and/or a sector site.

• 3 sector parameters listed here.

Level Site Cell Cell Cell Cell Cell UMTS cell layer #1 #2

Tab General General Cell Config Cell Config Cell Config Cell Config Antenna/TRX

Field Hex Radius Model Antenna Downtilt Height Azimuth PA output

Setting #1 UMTS 85 XP 4 20 #2 33

Will depend on area type eg Urban/Suburban/Rural Typically either 0º, 120º, 240º or 60º, 180º, 300º.



Creating 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 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 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 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 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).

Create Traffic Raster

Capture Traffic

Evaluate Each Cells Required Capacity

• Evaluate if each cell has sufficient capacity.

Re-Engineer Network (if required)



Create 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 Unclassified Urban Suburban Residential Village Isolated Dwellings Open Rural Woodland Forest Park Recreational Industry Water Airport Open in urban Agricultural land Pylons Sea Rivers

Weight 0 500 20 10 1 1 2 5 10 0 5 30 1 1 0 0



Spread Voice Traffic • Spread the traffic on the voice terminal type over the island.



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 Traffic • Use the traffic analysis tool to estimate the voice traffic per cell.

Cell: CS Traffic(E) Site0A: 1.27874 Site0B: 18.989 Site0C: 2.64128 Site1A: 18.1042 Site1B: 0.099755 Site1C: 1.71587 Site2A: 2.13376 Site2B: 1.58312 Site2C: 105.062 Site3A: 11.8475 Site3B: 2.43671 Site3C: 12.1231 Site4A: 2.06883 Site4B: 1.76368 Site4C: 1.87409 Site5A: 1.58884 Site5B: 3.31571 Site5C: 3.13637 Site6A: 1.81907 Site6B: 3.5485



Spread Data Traffic • Spread the traffic on the data terminal type over the island.



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 Traffic • Use the traffic analysis tool to estimate the voice traffic per cell.

Cell: Site0A: Site0B: Site0C: Site1A: Site1B: Site1C: Site2A: Site2B: Site2C: Site3A: Site3B: Site3C: Site4A: Site4B: Site4C: Site5A: Site5B: Site5C: Site6A: Site6B: Site6C:

Packet users 0.617848 9.13428 1.23677 9.05208 0.0498775 0.769083 0.732088 0.687448 52.4403 5.71852 0.963885 5.90523 0.496473 0.396895 0.889275 0.337783 0.733785 0.781533 0.754625 1.74732 1.42162



Evaluating Traffic Requirements (1) Load

Spare capacity for which can be allocated to non real time applications

Peak traffic Average circuit switched traffic

Real time non-controllable load

Time


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 must convert 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 circuits captures: !

1.58 Erlangs of voice traffic.

!

0.69 384kb/s data users.



Evaluating Traffic Requirements (3) Captured circuit switched Traffic = 1.58 Erlangs

Average capacity available for packet data Erlang B Formula (2% GOS)

5 circuits required

= 5 - 1.58 = 3.42 Erlangs or 3.42 x 12.2 = 41.69 kb/s Offered packet data

5 Erlangs 3.42 Erlangs 1.58 Erlangs

= 0.69 x 384 = 263.98 kb/s Extra capacity required for packet data = 263.98 - 41.69 = 222.29 kb/s or 222.29 = 19 voice equivalent circuits 12.2 Total voice equivalent circuits required = 5 + 19 = 24



Evaluating Traffic Requirements (4) Voice (erlangs offered)

Site0A: Site0B: Site0C: Site1A: Site1B: Site1C: Site2A: Site2B: Site2C: Site3A: Site3B: Site3C: Site4A: Site4B: Site4C: Site5A: Site5B: Site5C: Site6A: Site6B: Site6C:

1.27874 18.989 2.64128 18.1042 0.099755 1.71587 2.13376 1.58312 105.062 11.8475 2.43671 12.1231 2.06883 1.76368 1.87409 1.58884 3.31571 3.13637 1.81907 3.5485 2.84358

Extra Extra Voice Total voice Data rate No of 384 Data rate capacity equivalent voice equivalent required kb/s available Voice required circuits circuits equivalent for packet packet for packet (circuits for packet available circuits required data data data required) data for packet for packet required (kb/s) users (kb/s) (kb/s) data data 5 3.72 45.40 0.62 237.25 191.85 16 21 27 8.01 97.73 9.13 3507.56 3409.83 280 307 7 4.36 53.18 1.24 474.92 421.74 35 42 26 7.90 96.33 9.05 3476.00 3379.67 278 304 2 1.90 23.18 0.05 19.15 0.00 0 2 6 4.28 52.27 0.77 295.33 243.06 20 26 6 3.87 47.17 0.73 281.12 233.95 20 26 5 3.42 41.69 0.69 263.98 222.29 19 24 118 12.94 157.84 52.44 20137.08 19979.23 1638 1756 19 7.15 87.26 5.72 2195.91 2108.65 173 192 7 4.56 55.67 0.96 370.13 314.46 26 33 19 6.88 83.90 5.91 2267.61 2183.71 179 198 6 3.93 47.96 0.50 190.65 142.69 12 18 6 4.24 51.68 0.40 152.41 100.72 9 15 6 4.13 50.34 0.89 341.48 291.15 24 30 5 3.41 41.62 0.34 129.71 88.09 8 13 8 4.68 57.15 0.73 281.77 224.63 19 27 8 4.86 59.34 0.78 300.11 240.77 20 28 6 4.18 51.01 0.75 289.78 238.77 20 26 8 4.45 54.31 1.75 670.97 616.66 51 59 7 4.16 50.71 1.42 545.90 495.19 41 48

OVERLOAD STATUS

OK OVERLOAD OK OVERLOAD OK OK OK OK OVERLOAD OVERLOAD OK OVERLOAD OK OK OK OK OK OK OK OK OK


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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