EM.Terrano Tutorial Lesson 3: Analyzing Indoor Propagation Inside A Multi-Story Building Model

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Tutorial Project: Analyzing Indoor Propagation Inside A Multi-Story Building Model
Terrano L3 Fig title.png

Objective: In this project, you will build an indoor propagation scene consisting of an office building interior with internal walls and will analyze the scene using the SBR method.

Concepts/Features:

  • Wizard
  • Variable
  • Penetrable Surfaces
  • Material Properties
  • Received Rays
  • Received Power Coverage Map

Minimum Version Required: All versions

'Download2x.png Download Link: EMTerrano_Lesson3

What You Will Learn

In this tutorial you will use a wizard to construct the geometry of a multi-story building model made of penetrable surfaces. You will also learn how to define and change variables. You will change the wall properties including their thickness and conductivity and will examine the effect of these changes on the wireless propagation.

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Getting Started

Open the EM.Cube application and switch to EM.Terrano. Start a new project with the following attributes:

Starting Parameters
Name EMTerrano_Lesson3
Length Units Meters
Frequency Units GHz
Center Frequency 1GHz
Bandwidth 1GHz

Constructing the Geometry of the Multi-Story Building

For this tutorial lesson, you will use a wizard to build the geometry of a office building. Click on the Office Building Wizard OfficeBuildingWizardIcon.png button of the Wizard Toolbar or select the menu item Tools → Propagation Wizards → Office Building.Two arrays of box objects appear in the project workspace, which represent the rooms and hallways of a two-story office building.

EM.Terrano's wizard toolbar.
The geometry of the two-story building created by the wizard.

Defining the transmitter & Receivers

For this tutorial lesson, you will define three base location sets called "BasePointSet_1", "BasePointSet_2" and "BasePointSet_3" with the colors blue, orange and purple, respectively. Under "BasePointSet_1", create a single point object for the transmitter. Under "BasePointSet_2" and "BasePointSet_3", create two arrays of base points for two separate receiver sets on the first and second floors according to the tables below:

Part Object Type Object Group Group Color Dimensions Coordinates
Point_1 Point Base_Point_1 Blue N/A (-15m, 12m, 3m)
Point_2 Point Base_Point_2 Orange N/A (1m, 1m, 1m)
Point_3 Point Base_Point_3 Purple N/A (1m, 1m, 5m)
Array Object Parent Object X Count Y Count Z Count X Spacing Y Spacing Z Spacing
Point_2_Array_1 Point_2 29 27 1 1m 1m 0
Point_3_Array_2 Point_3 29 27 1 1m 1m 0

Define a new default transmitter set associated with BasePointSet_1. Similarly, define two separate new receiver sets associated with BasePointSet_2 and BasePointSet_3. At this time, your project workspace must show a scene like this figure:

The propagation scene with the two-story buildings, vertical half-wave dipole transmitter and receiver grids.

Running a SBR Analysis

At this time, you are ready to run a quick SBR analysis of your propagation scene. But you need to keep in mind that in indoor propagation scene an extremely large number of reflected rays may be produced due to successive bounces from all the walls, ceilings and floors. If you don't limit that maximum number of ray bounces, the simulation time may increase significantly. Open the simulation run dialog and click the Settings button next to the simulation engine type drop-down list. This opens up EM.Terrano's simulation engine settings dialog. At the top of the dialog, you can see a box labeled Max No. Ray Bounces that has a default value of 10. Reduce this value to Nref = 4.

EM.Terrano's simulation engine settings dialog.

Run an SBR analysis of your indoor propagation scene and visualize the coverage maps of the two receiver sets at the first and second floors.

The received power coverage map of the indoor propagation scene on the first floor with Nref = 4.
The received power coverage map of the indoor propagation scene on the second floor with Nref = 4.

Now visualize the rays in the scene. You may want to hide the second receiver set for more clarity. Remember that by default, the first receiver of the first receiver set is always selected as the active receiver for ray visualization. Open the property dialog of ReceiverSet_1, select its first receiver element and view its ray data dialog. You will see a total of 9 rays received by the first receiver.

The ray data dialog of the first receiver on the first floor with Nref = 4.
The 3D visualization of the rays received by the first receiver on the first floor with Nref = 4.

Next, open EM.Terrano's simulation engine settings dialog again and set the value of Max No. Ray Bounces to Nref = 8. Run another SBR analysis of your indoor propagation scene and visualize the coverage maps of the two receiver sets at the first and second floors.

The received power coverage map of the indoor propagation scene on the first floor with Nref = 8.
The received power coverage map of the indoor propagation scene on the second floor with Nref = 8.

Also visualize the rays received by the first receiver on the first floor. With Nref = 8, this receiver receives a total of 68 rays.

The 3D visualization of the rays received by the first receiver on the first floor with Nref = 8.

Changing the Wall Properties

The office building created by the wizard is highly parameterized. Open the Variable Dialog by clicking the Variable icon tn.png button on the Simulate Toolbar or selecting the menu item Simulate → Functions.... You will see a long list of variables related to the dimensions of the rooms and hallways, number of rooms along the X, Y, Z directions, as well as the wall properties.

EM.Cube's variables list showing the office building's parameters.

Select and highlight the variable "sig" from the list (corresponding to the wall conductivity) and click the Edit button of the dialog to open "Edit Variable" dialog. Change the definition or numeric value of "sig" from the original value of 0.001 to 0.1.

Changing the value of the wall conductivity.

Similarly, edit the variable "wall_thickness" from the list and change it from the original value of 0.25m to 0.5m.

Changing the value of the wall thickness.

Once all the changes take effect, run a new SBR analysis of your indoor propagation scene and visualize the receiver power coverage maps on both floors. From the figures below you can see a significant drop in the power levels of the receivers on both floors.

The received power coverage map of the indoor propagation scene on the first floor with thicker walls and higher wall loss.
The received power coverage map of the indoor propagation scene on the second floor with thicker walls and higher wall loss.

 

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