METHOD OF CALCULATION

Methodology to be used for estimating the propagation of electromagnetic waves through space. It is necessary to decide which simulation model you want to use in each case, depending on the environment in which the network is going to be deployed, the technology used, the work frequency bands and the quality of cartographic information available to model the terrain. By creating a new study, Xirio Online, by default, proposes the most suitable method for the calculation required.

It is possible to create the calculation method from a template or create a new one. In the first case a copy of the selected template is loaded, so that the template will not be modified.

The possible methods of propagation are determined by the study service that is being configuring.

The calculation methods of Xirio Online are based on a series of basic or standards models, usually promoted by international Recommendations, to which it is possible to configure settings for more precise adjustment due to circumstances of the planning.

The parameters to be set in the window corresponding to the method of calculation will depend on the basic propagation method selected by the user:

The basic propagation methods are:

- ITU-R Rec. 526: Deterministic calculation method based on difraction losses. It is valid for frequencies above 30 MHz. Recommended for all radio services in rural and sub-urban environments , where medium or high-resolution mapping is available. Read more.

- Deygout: Deterministic calculation method based on difraction losses. It is valid for frequencies above 30 MHz. Recommended for all radio services in rural and sub-urban environments, where medium or high resolution mapping is available. Read more.

- Line of sight: Calculation method that provides signal level prediction only in clearance conditions, using the free space attenuation. Read more.

- ITU-R Rec. 1546: Empirical calculation method in the frequency range from 30 MHz to 1 GHz. It is valid in rural environments for any radio service, and especially recommended for sound and video broadcasting for distances above 100km or where accurate mapping is not available. Read more.

- Okumura-Hata: Empirical calculation method valid in the frequency range from 150 MHz to 2 GHz. Recommended for mobile services and broadband access services in rural and urban environments, where high-resolution mapping is not available. Read more.

- Modulated Okumura-Hata: Hybrid calculation method valid in the frequency range from 150 MHz to 2 GHz. Based on the Okumura-Hata method, the model makes a correction for diffraction losses. Recommended when using high-resolution mapping in urban environments. Read more.

- Xia-Bertoni: Deterministic calculation method valid in the frequency range from 800 MHz to 2 GHz. Recommended for urban environments in mobile services and broadband access services. It requires urban cartography with building information (DEM). Read more.

- ITU-R Rec. 1411: Deterministic calculation method valid in the frequency range from 800 MHz to 5 GHz. Recommended for urban environments in mobile services and broadband access services. It requires urban cartography with building information (DEM). Read more.

- COST 231: Deterministic calculation method valid in the frequency range from 800 MHz to 2 GHz. Recommended for urban environments in mobile services and broadband access services. It requires urban cartography with building information (DEM). Read more.

- Stanford University Interim: Empirical calculation method valid for frequencies below 11 GHz. Recommended for mobile services and broadband access services (especially WiMAX) where urban cartography with building information (DEM) is not available. Read more.

- ITU-R Rec. 1812: Deterministic calculation method valid in the frequency range from 30 MHz to 3 GHz. Used in rural and mixed environments for all radio services, especially broadcasting, where medium or high resolution mapping is available. Read more.

- ITU-R Rec. 452: Deterministic calculation method valid in the frequency range from 700 MHz to 50 GHz. Highly recommended for interferences calculation in fixed service links. Read more.

- ITU-R Rec. 530: Deterministic calculation method valid for frequencies above 30 MHz. It incorporates the feasibility analysis of digital radio links in fixed services. Read more.

- Defined by user: Calculation method configurable by user in which is possible to define the basic propagation signal losses using a formula set manually by the user. Under the terms of that formula would be may intervene the distance (Km), the frequency (MHz), the height of the transmitter (m), the height of receptor (m), the effective height of transmitter (m) and the diffraction loss (dB).

Below are shown the corresponding parameters in case of choosing, for example, the method of propagation 526:

 

There are parameters that are common to all methods of propagation and others which are specific to each one, in the example would be the properties of the method 526.

The common parameters of all methods of propagation are:

- K Factor: Factor of curvature of the earth in the geographical area of the land on which the calculations are made. It depends on the tropospheric refractive index.

- Resolution: Used resolution for calculations. It is usual to choose the same resolution of the mapping used. However, in some cases it is useful to begin working with poorer resolutions, to get a quick and rough calculation, changing later to obtain more accurate results.


- Margin of fading: Only applicable in simulations of mobile service. Parameterizes the distribution of signal versus time and locations where the reception threshold only includes medium signal values (for 50% of time and 50% of locations). It is obtained by a standard deviation depending on the working frequency and a statistical distribution log-normal or Rayleigh. The final obtained results will be signal level exceeded in the percentage of time and / or locations used to calculate this "fading margin".

 

 

 

Home