PGM-A Technical Notes.pdf

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PGM-A Propagation Model

PGM-A Propagation Model

The PGM-A propagation model emulates the Asset The PGM-A propagation model emulates the Asset

 propagation model and is intended to enable users to re-use  propagation model and is intended to enable users to re-use  propagation models in Planet

 propagation models in Planet EV  EV  that have been tuned using that have been tuned using Asset. This propagation model is not distributed with

Asset. This propagation model is not distributed with Planet

Metapath Software International (US), Inc. A Marconi Company

 Notice

This document contains confidential and proprietary information of Metapath Software International (US), Inc., a Marconi company (“MSI” or “Marconi”) and may not be copied, transmitted, stored in a retrieval system, or reproduced in any format or media, in whole or in part, without the prior written consent of Marconi. Information contained in this document supersedes that found in any previous manuals, guides, specifications data sheets, or other information that may have been provided or made available to the user. This document is provided for informational purposes only, and Marconi does not warrant or guarantee the accuracy, adequacy, quality, validity, completeness or suitability for any purpose the information contained in this document. Marconi may update, improve, and enhance this document and the products to which it relates at any time without prior notice to the user. MARCONI MAKES NO WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, THOSE OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

PURPOSE, WITH RESPECT TO THIS DOCUMENT OR THE INFORMATION CONTAINED HEREIN.

Trademark Acknowledgement

Marconi, Metapath, Ceer, Planet NOVA, Ceos, Planet, and deciBel Planner are trademarks or registered trademarks of the Marconi group of wireless telecommunication companies which include MSI, Metapath Software International Limited, and Northwood Technologies, Inc. WaveSight is a trademark of Wavecall. This document may contain other trademarks, trade names, or service marks of other organizations, each of which is the property of its respective owner.

Introduction

The PGM-A propagation model enables customers migrating from Asset to re-use their tuned Asset macrocell models within Planet EV . The algorithms used in the PGM-A propagation model are modified versions of those used in the PGM propagation model included with Planet EV . As you would do in Asset, you can define model parameters (k-factors) that influence results. Using the PGM-A propagation model, you will produce results that are comparable to those achieved using Asset in the most common

implementations of the model. Results will not be precisely the same. However, performance is very comparable to Asset.

Although it is typically recommended that you use Planet EV  models and tune them using measurements, it can be a more cost effective approach to

replicate Asset models in Planet EV  using the PGM-A model as there is no need to retune models.

This document provides the information necessary to successfully use the PGM-A propagation model, and it is intended for use during evaluation  periods or when Marconi Wireless implementation services are not being

used. This document explains how to add the PGM-A propagation model and associated user documentation to Planet EV , details some key differences  between the PGM and the PGM-A propagation models, and explains how to

edit the PGM-A propagation model.

Prerequisites to PGM-A propagation model use

In order to successfully use the PGM-A propagation model to migrate tuned Asset macrocell models to Planet EV , the following requirements must be met  before using the PGM-A propagation model:

1 _{Project data and site configurations must be converted for use in} Planet EV .

The project must be set up to replicate the Asset project. It is imperative that the site configuration, antenna data, and all related parameters are

The performance of prediction generation using the PGM-A model has proven to be very similar to that of the original Asset predictions.

However, the performance is not guaranteed and use of this model is optional.  All efforts will be made to support this propagation model in the event of a

defect; however, it is distributed as an Add-on tool that is not part of the standard software warranty.

identical to those in Asset. Planet EV  utilities are available to support this effort. For more information, contact Technical Support.

2 _{The geodata (height and clutter data) must be the same files as those} available in Asset in order to achieve similar results.

3 _{Clutter classes must have the same names or be mapped using the} Planet EV  Clutter Property Assignment dialog box.

 Adding the PGM-A propagation model and user documentation

to Planet

EV

The PGM-A propagation model is not part of the standard Planet EV 

installation. As the model has a very specific purpose (i.e., supporting

customers migrating from Asset), it is only distributed to specific customers or for specific projects. It is available upon request from Technical Support or Product Management.

To add the PGM-A propagation model and user

documentation to Planet

EV

1 _{Copy the PGM-A.mdl to the Planet EV /mdl folder.} 2 _{Copy the PGMA.chm file to the Planet EV /Help folder.}

3 _{Copy the PGM-A Technical Notes.pdf file to the Planet EV /Help/User} Guides folder.

Currently, there is no automated method of converting Asset model data into Planet EV _{model (.dpm) files or related Clutter Property}

 Assignment (.cpa) files. This must be done manually.

In Asset, model parameters are saved in the Model-List001.XML file. This file provides quick access all model parameters (alternatively, you can view model parameters in the Asset user interface).

Typically, the distribution and installation of this propagation model and the conversion of Asset models will be part of a Planet EV

Implementation service. It is strongly recommended that customers make use of these services for migration projects.

Workflow for using the PGM-A propagation model

Step 1

Open the Model-List001.XML file generated using Asset. The model name is listed in the ID column and is shown on multiple lines (one line for each clutter class). K factors for a model will be listed on several lines but the values will all be the same.

Step 2

Edit PGM-A propagation model parameters replicating the Asset model. See “Editing PGM-A propagation model parameters” on page 5.

Ensure that the model name is exactly the same as that used in  Asset.

Step 3

Create a Clutter Property Assignment (.cpa) file to associate with the new model. See “Creating a .cpa file for the PGM-A

propagation model” on page 10.

Step 4

For every Asset model, repeat the steps of the workflow to create a model (.dpm) file in Planet EV_.

Editing PGM-A propagation model parameters

The first step in the creation of a new propagation model is to edit model  parameters. Then, you need to create a clutter property assignment (.cpa) file

to associate with it.

To edit PGM-A propagation model parameters

1 _{Open a project in Planet EV .}

2 _{In the Project Data category, right-click Propagation Models and} choose New.

3 _{In the Propagation Model Type dialog box, choose PGM-A and click} OK.

4 _{On the Settings tab, in the Frequency box, define the frequency as shown} in the FREQUENCY column of the Model-List001.XML file.

5 _{In the Receiver Height box, define the receiver height as shown in the} MOBILE-HEIGHT column of the Model-List001.XML file.

6 _{From the Earth Curvature list, choose one of the following options:} ■ 4/3 Earth Curvature —when the value in the EARTH-RADIUS

column of the Model-List001.XML file is approximately 8500. ■ Normal Earth Curvature —when the value in the

EARTH-RADIUS column of the Model-List001.XML file is approximately 6400.

7 _{Click Edit.}

8 _{On the General tab, in the Model Type section, choose one of the} following options:

■ 1 piece —this type of model uses factors K1 to K7. Factors K1 (near) and K2 (near) are not used to define a 1-piece model. ■ 2 Piece —this type of model uses factors K1 to K7 as well as

K1 (near) and K2 (near).

9 _{If you chose the 2-piece model, in the Distance box, define the distance} (in meters) at which to use the constants K1 (near) and K2 (near).

10 _{In the K Factors section, define the K1 to K7 values as the K1 to K7} values in Model-List001.XML file or Asset GUI.

11 _{If you are using a 2-piece model, in the K1 (near) and the K2 (near)}  boxes enter a value between -150 and 250.

13 _{If clutter through loss is used in the Asset model, enable the Enable the} Path Clutter check box and define the distance as the K12 value

contained in the Model-List001.XML file or Asset GUI. 14 _{Click the Diffraction tab.}

15 _{In the Knife-Edge Merging Distance box, define the distance as K11 in} the Model-List001.XML file or Asset GUI.

16 _{Click the Effective Antenna Height tab.}

17 _{Choose one of the following options:}

■ Absolute —this is the same as the “Base Height” algorithm in Asset.

■ Relative —this is the same as the “Spot Height” algorithm in Asset.

■ Average —this is the same as the “Average Height” algorithm in Asset. You must define the ground level in the prediction area when you chose this type.

■ Slope —this is the same as the “Slope” algorithm in Asset. You must define the slope distance, the minimum height, and the maximum height when you chose this type.

18 _{When you have finished editing the propagation model parameters, click} OK.

19 _{Create a .cpa file to associate with the model. See “Creating a .cpa file for} the PGM-A propagation model” on page 10.

Creating a .cpa file for the PGM-A propagation model

In order to create a new model, you must create a .cpa file to associate with it. 1 _{In the Propagation Model Editor, click the Clutter Properties tab.}

2 _{Click Edit CPA.}

If your project uses clutter, clutter classes are automatically displayed in the Clutter Property Assignment dialog box.

3 _{In the Clutter Property Assignment dialog box, ensure that the clutter} classes contained in theModel-List001.XML file are listed in the

Reference Name box.

4 _{Define the Clutter Absorption Loss for each clutter class as contained in} the OFFSET column of the Model-List001.XML file.

5 _{Define the Through Clutter Loss for each clutter class as contained in} the MOBILE-HEIGHT3 column of theModel-List001.XML file.

6 _{From the File menu, choose Save As to save the .cpa file.}

7 _{In the Save As dialog box, in the File Name box, type a name for the file} and click Save.

8 _{Click Close.}

10 _{In the Save As dialog box, in the File Name box, type the same name for} the propagation model as that used in Asset and click Save.

11 _{Click Close.}

The new propagation model is added to the Propagation Models node in the Project Data category of the Project Explorer.

For additional information on propagation models, or for information on working with Planet EV , see the Planet EV User Guide.

Comparing the PGM and PGM-A propagation models

Both the Asset model and PGM model support two-piece models, where two sets of slope and intercept and are defined. One set is used for near Tx  predictions (d < distance) and the second set for predictions (d > distance). In

the PGM model, distance is entered in meters while in the Asset model, distance is entered in km.

PGM propagation model

The received signal strength at the mobile is given by the following equation in the PGM propagation model.

Equation 1.1 Received signal strength in the PGM propagation model

Where

 is the receive power in dBm.

 is the transmit power (ERP) in dBm.  is the constant offset in dB.

 is the multiplying factor for log(d).

With the two-piece model, both and can be assigned two sets of values. One set is used for d< distance and the other for d> distance, where distance is the distance in meters away from the base site specified in the Model Editor.

 is the multiplying factor for log( ). It compensates for gain due to antenna height.

K ₁ K ₂

P _RX  P_TX  K ₁ K ₂log( )d  K ₃log( H _{ef f} ) K ₄ Di ff ra ct io n K ₅log( H _{ef f} )log( )d  K ₆(H _meff ) K _CLUTTER + + + + + + + = P _RX  P_TX  K ₁ K ₂ K ₁ K ₂ K ₃ H _{ef f} 

 is the multiplying factor for diffraction calculation.

is the Okumura-Hata type of multiplying factor for .

 is the correction factor for the mobile effective antenna height gain ( ). d is the distance, in meters, of the receiver from the base site.

 is the effective height of base site antenna from ground.

Diffraction is the value calculated for loss due to diffraction over an obstructed path. The value produced is a negative number, so a positive multiplication factor, is required.

 is the gain in dB for the clutter type at the mobile position in Planet DMS_{. In}

Planet EV_{, represents a loss.}

 is the mobile effective antenna height.

PGM-A propagation model

In order to achieve similar results to those obtained using the Asset model, the PGM-A propagation model received signal equation (Equation 1.1) was

modified. The following sections detail key mappings between the two models:

■ K-factor mapping. See “K-Factor mapping” on page 13. ■ effective transmit antenna height mapping. See “Effective

receive antenna heights mapping” on page 13.

■ clutter parameters. See “Clutter parameters” on page 13.

■ diffraction loss calculations. See “Diffraction loss calculations” on page 14. K ₄ K ₅ log( H _{ef f} )log( )d  K ₆ K ₆ H _{ef f}   H _{ef f}  K ₄ K _CLUTTER K _CLUTTER  H _meff 

K-Factor mapping

K factors in the Asset propagation model can be mapped to those in the PGM model as follows:

Where

The capital letter K indicates a K-factor in the PGM propagation model and small letter k indicates a K-factor in the Asset model.

Effective receive antenna heights mapping

In Asset model, the height of Rx antenna is defined as the height of the mobile above ground. However, in the PGM model, an effective Rx height is used, as this typically leads to more accurate predictions.

Clutter parameters

The following table contains a comparison between the parameters in the Asset model versus those in the PGM model.

In the mapping equation for K₁, the k₄(logH_ms) term is only valid if the Rx height is defined globally and not per clutter. If the Rx height is defined by clutter, then the Rx height must be set to zero.

 As set Mod el PGM

Offset-loss (dB) Clutter Absorption Loss Height Clutter Height (m)

Separation (m) Clutter Separation

K ₁ = –

(

k ₁ –

3

k ₂ + k ₄

log

(

H _ms

)

)

K ₂ = k ₂ pa K ₃ = –( k ₅–3k ₆) K ₄ = k ₇ K ₅ = –k ₆ K ₆ = –k ₃

Diffraction loss calculations

In the Asset model, there are four methods for computing diffraction losses due to radio wave propagation over obstacles. These methods include the Bullington, Japanese Atlas, Deygout, and Epstein-Peterson methods. PGM only includes a modified version of the Epstein-Peterson method for

computing losses due to diffraction, which is automatically balanced with a Bullington algorithm, as a function of the profile characteristics; this method  provides more accuracy as it allows for an automated adaptation of the

algorithm for each predicted point. In this method, if there are more than three knife edges between the Tx and Rx, the first two knife edges are fixed, but the remaining knife edges are combined into the third knife edge. Both PGM and Asset models include an option for merging the distance of knife edges where knife edges with a distance of less than the merging distance are represented as a single knife edge.

Through-loss (dB) Through Clutter Loss is mapped to the Path Clutter parameter in PGM via the following: ■ Through-loss Distance was mapped to Path

Clutter Distance

■ Function Coefficient was set to 1 ■ Triangular Function type was selected

■ The Clutter Properties Assignment dialog box was modified to include the Through-loss parameter defined in the Asset model Through-loss Distance