Indoor Network Design in Ics Telecom-Eng

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INDOOR NETWORK DESIGN IN ICS TELECOM 0

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INDOOR NETWORK DESIGN IN ICS TELECOM


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TABLE OF CONTENT 1 INTRODUCTION ____________________________________________________________ 2

2 PROJECT SETUP ____________________________________________________________ 4

2.1 Convert Tiff files _______________________________________________________________ 4

2.2 Draw the separators _____________________________________________________________ 6

3 NETWORK SETUP ___________________________________________________________ 7

3.1 Access Point creation ____________________________________________________________ 7

3.2 Generate Subscribers ____________________________________________________________ 9

4 PROPAGATION MODEL _____________________________________________________ 10

5 COVERAGE AND CONNECTIVITY ____________________________________________ 13

6 FREQUENCY ASSIGNMENT/INTERFERENCE ANALYSIS _______________________ 14


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1 INTRODUCTION ICS Telecom incorporates Indoor network deployment functions for WiFi applications. It integrates new design

and coverage analysis functions in order to perform any indoor network design, including W-LAN (WiFi,

802.11-b).

The building data can be manually extracted using ICS Telecom from a basic digitized floor plan. Based

upon the material crossed (walls in concrete, separators in brick on the same floor...) standard or manual

attenuations can be applied, as well as attenuation when a ceiling/floor is crossed. From this model, Indoor

coverage analysis can be performed taking into account a network located on the same floor, or on a different

one: find the best location for the stations, use the frequencies available the best way as possible (detailed

frequency assignment in order to minimize interference areas).

The technology that we will simulate in this example is WIFI application at 2.4 GHz. However, all principles

can also be used when working with other technologies.


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This example is done with a sample of basic digitized floor plan. This data contains the following elements:

• One Separators Model (produced at 10 cm resolution). This separators file (*.IDR file) gives at each

point the different classes of material: concrete (code 1), brick (code 2), plaster, metal…. This

resolution is commonly used to simulate WIFI networks, but lower resolutions until 1 cm can be used

to simulate other technologies.

A list of technical features is associated to each material class and is used for propagation simulation,

interference analysis, user's attenuation or to modify the propagation model according to

measurement survey… The user can modify all of these parameters (see "Tools �Indoor parameters"

menu).

• Two image files (*.img file and *.pal file for the colour information) can be displayed based on a

scanned floor plan.


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2 PROJECT SETUP There are two steps to create an indoor project in ICS Telecom:

- Convert the TIF file (scanned floor plan) to IMG, PAL, SOL and IDR files.

- Create the separators as vectors layers.

2.1 Convert Tiff files

• Start ICS Telecom

• Open the Indoor Project window

• In the opened window, select the Tiff file and click on open.

• In the opened window, choose a directory and give a name to the project and click on save.

• Define your Tiff step (m) and the Project step (m) on which you want to work.

• Click on OK

The Idr, Img, Pal and Sol files are automatically created and saved under the project name. Its can be

visualized in the Project Manager window.


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And the project is automatically loaded.


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2.2 Draw the separators

In order to draw the separators as vectors layers, a vector file must be defined.

• Create a vector file by clicking on "Map menu � Vector Map � New vector file".

• Select the Polyline Draw in the left tool bar .

• Left click on the map, select “Draw dtm/indoor line”

• Draw your indoor line; right click on the map to stop.

• Select “continue” and “add to dtm/indoor layer”

• In the opened window define the indoor code you want to associate to the separator and click on

OK.

If you pass your cursor on this new vector layer, the code associated is displayed in the main bar

.

Follow the same steps for all the separators you want to draw.


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3 NETWORK SETUP After having defined the project, a network must be created.

We will see two ways to define a WIFI network.

1 Place and set up the Access Point.

2 Generate potential subscribers and find the best position for Access Points.

3.1 Access Point creation

• Left click on the position wanted.

• Select "Add Tx/Rx" in the pop-up menu:

(Note that you can create an access point anywhere on map by left-clicking on map and selecting "Add

Tx/Rx".)

The parameter box appears:


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The parameters must be set in order to simulate the technology wanted. In our case the parameters set

are for the WIFI technology.

• Set all the parameters and the signal by choosing “RLAN FHSS” in the general window.

• In the Advanced window a floor offset can be defined in order to take into account the attenuations

due to the floor via a floor factor.

• Click on "OK" to close the "Tx/Rx parameters" box.

The parameter box can be open at any time by clicking on the station icon on map, then selecting the

name of the Access Point and clicking on "parameters".

The access points are now created to simulate a WIFI network and are displayed on the map.


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3.2 Generate Subscribers

To generate subscribers please report to the Subscribers tutorial.


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4 PROPAGATION MODEL In an indoor environment the degradations of an interior signal related to the propagation are due to two main

phenomena:

- Reflection on, and diffraction by, objects (including the walls and the floors) inside the parts;

- Loss transmission by the walls, the floors and others obstacles

In order to take into account these phenomena, ICS Telecom bases its simulation on the deterministic (or

adapted to the site) propagation model ITU-R 525 associated with adapted subpath attenuation and an

adapted diffraction.

This model takes into account the path degradation; not only degradation in free space, but also an additional

degradation due to the obstacles and the transmission in building materials and takes into account the vertical

and horizontal multipath propagations.

This method takes also into account the direct ray and the rays resulting from only one reflection.

All these considerations are possible thanks to precise information on the structure of the building which can

be defined on ICS Telecom.

• Open the propagation models window.


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• Select the ITU-R 525 model, the visibility/Indoor diffraction and the standard subpath attenuation.

The Visibility/Indoor diffraction detects the obstacles and takes into account the absorption of the signal due

to these obstacles.

The selected subpath model takes into account the attenuation due to the multipath along the floor plan only.

The other attenuation parameters are handled by applying the attenuation per material, not according to a

diffraction method, which is not applicable to an indoor environment.


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The reflections of the vertical surfaces can be taken into account by checking the 3D reflection engine.

• In the propagation models window select the option “3D coverage only” in the reflection part.

This model calculates the field strength at all point of the simulation area according to the reflected signals

contribution, taking into account a reflection coefficient defined by the user in the Ground occupancy

parameters box (if a ground occupancy file . sol is included in the project), or entered by the user in the

Reflectance field of the Propagation Models box. All seen points re-transmit the power received from the

transmitter (multiplied by the reflection coefficient) over 360°, the gain of the reflecting surface is calculated

according to the angle for 1 m² surface.

The setup of the attenuation per material is defined in tools\indoor parameters.

• Go on Tools/Indoor parameters

The attenuation per material can follow the ITU-R 1225 recommendation (automatic mode), or can be

manually defined (manual mode).


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- In automatic mode (default mode), the system considers only two materials: the walls and

partitions. The codes 1 to 3 correspond to walls, and the codes 4 and 5 correspond to

partitions.

The attenuation is calculated as follows:

Attenuation = (1.39 ´ Number of partitions crossed) + (2.38 ´ Number of walls crossed)

- In manual mode the user must input the attenuation for each material code.

The attenuation is calculated as follows:

Attenuation = (User attenuation ´ Number of obstacles) ´ User coefficient Thickness coefficient

5 COVERAGE AND CONNECTIVITY Once the technical parameters of one or several Access Points have been defined, the user can calculate the

coverage area, based upon a proper propagation model. The coverage areas can easily be analyzed:

covered/non covered, shadowed area, composite coverage, best server coverage … (Cf Main functions

document)

For the connection of Wireless devices to Access Points three deployment steps can be analyzed:

- Full Automatic Network deployment:

ICS Telecom performs automatically a coverage analysis from the handset database. The best

locations are found, placed in dedicated locations defined by the user or not.

- Completion of an existing network:

Part of the network already exists, but it needs to be completed in order to extend the

coverage area. ICS Telecom can setup automatically the extension in accordance with the

already existing access points: new locations (placed if wanted in preferred areas like walls,

hidden places, closets…), interference minimized for the entire network…

- Connection validation:

ICS Telecom allows you to validate the connection of handsets to the already existing

network, based upon several rules (limited or not to the number of lines available, bit rate…)


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6 FREQUENCY ASSIGNMENT/INTERFERENCE ANALYSIS

The locations of the access points are defined, the tool can help you to optimize the usage of the frequencies

available, while attaining the maximum area coverage by the resulting station configuration. According to the

frequency plan and the spectrum occupancy, ICS Telecom assigns interference free frequency to the access

point. The function optimizes the re-use of frequencies as much as possible.

Once the frequency plan has been validated, remaining interference areas can be located, analyzed, and

removed (or minimized to areas of non-interest) if possible by adjusting the network configuration.

Please report to the Frequency Assignment and interference analysis document.

Documents

Indoor Network Design in Ics Telecom-Eng