wiki:Manual/PropagationModels/LongleyRice
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Longley Rice propagation model plugin

Introduction

The Longley-Rice (Area prediction mode) propagation model was developed as SEAMCAT plug-in in the  National Telecommunications Institute (Poland) in co-operation with the  Wrocław University of Technology. The task was performed under Research Project of the Polish Ministry of Science and Higher Education entitled: Next generation teleinformatics services - technology, application and market aspects (no. PBZ-MNiSW-02/II/2007).

Initially, it used two types of plug-in available in SEAMCAT: Propagation plug-in and also post processing plug-in. The second one is needed for setting input parameters values. Eventually, with the coming of SEAMCAT 4.0.0 new interface, the GUI of the propagation plugin allowed to implement the Longley-Rice into one only propagation plugin (see download instruction).

The Longley-Rice (Irregular Terrain Model) propagation model in area prediction mode (i.e. no need for terrain profile details to make a path loss calculation) was developed for SEAMCAT. The propagation model can be used in a wide frequency range: 20 MHz – 20 GHz and is widely used in the USA and other countries.

The ITM model returns predicted median attenuation of a radio signal, regarding not only statistical terrain, system, climate parameters but also variability of the signal in time and in space, assuming a level of confidence. Longley-Rice computes path loss into three regions:

  • Line-of-sight range,
  • diffraction range and
  • scatter range (In distance between 1 – 2000 km).

ITM model is based on electromagnetic theory and on statistical analysis, the original model was developed in 1960’s in the USA. Further details of the model can be found here.

Download and testing of the plugin

The plugins are available in a .zip file containing the source code .java and the executable .class and the .jar if you want to allow embedding of your plugin into workspaces )

Name ver.1
Date 09/10/2013
LongleyRicePlugin download here (zip file containing .java and .jar)
Comment The previous version implemented using The postprocessing plugin has beem merged to use the new propagation plugin interface (see Archive bellow).
The calculation is unchanged
Compatibilty Compatible SEAMCAT 4.0.0 and onward (previous SEAMCAT versions do not support this version)

The results have been pre-tested and confirmed that they are consistent with expected value. The calibration test made by the National Telecommunications Institute can be found here.

How to load and use the plugins

Load the .class file or the .jar file (to allow embeddement) on your SEAMCAT plugin folders (see plugin section with embeddement)

The interface is self explanatory (note the usage of tooltips)

Archive

This archive present the longley Rice when it was implemented using the postprocessing plugin. Plugins: The source codes (2 .java files) are available ( a)Longley Rice algorithm b) configuration file) and the plugin in .jar format (containing several .class files) is freely downloadable from here.

To load the post-processing plugin implementation: You need to load the propagation model with embeddement. Choose the .jar file where the .class files are stored and in the In the fully Qualified Classname form of the Propagation model plugins write: LongleyRice. Then you need to load the Post processing plugin to configure it. In Fully Qualified Classname form of the Post processing plugin this time write: ConfigureLongleyRice, the Name/Reference populates as type and you can edit it. You can now set your propagation model in the victim or the interfering link. If you do not want to embed follow the instruction from the separate page.

Using Longley-Rice model: To use the plugin in the scenario you should select the Library plugin-class and select Plugin in propagation model selection



Then you must add the postprocessing plugin by select Workspace -> Post processing plugins, and configure it.



You can set different links (victim and Interfering) using different configuration of the Longley-Rice plugins . The plugin allows up to 99 links to be configured differently(i.e. the highest ID number should be 99).

To use the plugins for a particular configuration of a link, please provide the same ID number in the fields:

  • Param1 (propagation model plugin)
  • Propagation Model ID (post processing plugin)

Params 2 and 3 of the propagation model plugin are not use.

The number of post processing plugin instances in a particular SEAMCAT scenario should be the same as numbers of links in which Longley-Rice propagation model is used. The rest of parameters should be in the range described in chapter two (Input parameters).

The mode of variability form is described by 4 value:

  1. Single
  2. Individual
  3. Mobile
  4. Broadcast

It is important to accept every writing value by pressing enter.

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