MLinkPlanner 2.0

Point-to-Point and Point-to-Multipoint Microwave Link Planning Software

User Manual

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Diffraction Analysis

Diffraction analysis allows the user to estimate diffraction losses due to obstacles on the path profile.

Strictly speaking, diffraction losses at the link should be avoided, especially in the high-frequency ranges where the accuracy of the path profile is comparable to the size of the first Fresnel zone.

Diffraction losses may be due to the inability to meet the clearance criteria as per Rec. ITU-R P.530-17, especially in the relatively low-frequency ranges (up to 2-4 GHz).

In MLinkPlanner 2.0, you can choose one of the following diffraction methods:

  • Rec. ITU-R P.526-15 (Complete Bullington method or Diffraction over multiple cylinders method)

  • Deygout principle method with correction ITU-R-P.526-11

  • Epstein-Peterson method

 

The method for calculating diffraction losses is selected in the Propagation Model menu.

To begin the analysis of diffraction loss on the link, select the required link, and click on the Diffraction analysis button in the upper toolbar.

 

Enter the heights of the antennas, as well as the K-factor for which you want to calculate the diffraction loss (after entering, press Enter), after which the result of calculating the diffraction loss on the path profile and the intermediate parameters will appear in the information window in accordance with the selected calculation method. In order to take into account the obtained results, click the Apply button. After this, the antenna heights in link parameters will change in accordance with the applied values.

Diffraction losses are calculated for a single path (by default, for the Main–Main path). If you want to estimate diffraction losses for other paths (Main–Diversity or Diversity–Main paths), you’ll need to change the height of the corresponding antennas.

When you calculate performance characteristics, diffraction losses are calculated automatically for each path based on the antenna heights and other parameters. These parameters are saved in the project file and can be defined for each path individually.

Parameters of Diffraction Analysis

Parameters of Diffraction Analysis

Value of K exceeded for 99.9% (ke) 

Consider vegetation according to Rec. ITU-R P.833-9

k-factor for Diffraction Analysis

Value of k-factor exceeded for approximately 99.9% of the worst month for the path profile according to Figure 2 in Rec. ITU-R P.530-17

In this case, the forest on the track profile is excluded from the diffraction calculation and the attenuation in the forest is calculated in accordance with Rec. ITU-R P.833-9 "Attenuation of signals by vegetation."

Figure 17. Bullington Diffraction Loss Analysis Rec. ITU-R P.526-15

Parameters for the Bullington Method of Rec. ITU-R P.526-15

Bullington Point

Bullington Point location

Luc, dB

Knife-edge loss for the Bullington point, dB

Lb, dB

Bullington diffraction loss for the path, dB

Lbs, dB

Bullington diffraction loss for the smooth path, dB

Lsph, dB

Spherical-earth diffraction loss, dB

L, dB

The diffraction loss for the general path, dB

Figure 18. Analysis of diffraction losses by the method of isolated cylinders according to Rec. ITU-R P.526-15

Displayed items for the method of isolated cylinders according to Rec. ITU-R P.526-15

Ray

Stretched String

Obstructions

Radiuses of the Cylinders

Sub-path Obstructions

60%F1 for Sub-path

Projections of Rays Intersecting above Obstacles

Baselines

60%F1 for Baselines

Minimum Space Between Points for One Obstruction

Obstruction No.

Sub-path Obstruction No.

Correction Factor Cn

Location, km

Clearance, m

V

Radius, km

Loss, dB

Total, dB

Show the ray line between antennas.

Show line Stretched string. This identifies the sample points which would be touched by a string stretched over the profile from the transmitter to receiver.

Show obstruction identifiers. The obstruction identifier numbers are shown in figures on a yellow background.

Show Radius equal to the radius of curvature at the obstacle top.

Show obstruction numbers on the Sub-path. The obstruction numbers on the Sub-path are shown on a blue background.

Show 60 % of the first Fresnel zone.

Show Projections of rays intersecting above obstacles.

Show Baselines.

Show 60% of the first Fresnel zone for baselines.

This parameter can be adjusted within 250 m–10 km for more accurate approximation of obstruction.

Identifier Number of Obstruction

Identifier Number of Obstruction on the Sub-path

Correction factor Cn according to Rec. ITU-R P.526-15

Location of Obstruction, km

Clearance at the Obstruction, m

Single dimensionless parameter according to Rec. ITU-R P.526-15

The radius of the Obstruction, km

Diffraction losses at each obstruction, dB

Total Loss, dB

Figure 19. Deygout Diffraction Loss Analysis Rec. ITU-R P.526-11

Displayed items for Deygout principle method with correction Rec. ITU-R-P.526-11

Dp, km

Distance to the main knife-edge obstacle, km

Dt, km

Distance to the knife-edge obstacle from the Tx side, km

Dr, km

Distance to the knife-edge obstacle from the Rx side, km

J(Vp), dB

Loss on the main knife-edge obstacle, dB

J(Vt), dB

Loss on the Tx knife-edge obstacle, dB

J(Vr), dB

Loss on the Rx knife-edge obstacle, dB

Empirical correction, dB

С, dB

Diffraction losses, dB

L, dB

Figure 20. Epstein-Peterson diffraction method

Displayed items for the Epstein-Peterson diffraction method

Obstruction №

Identifier Number of Obstruction

Distance, km

Distance to the knife-edge obstacle, km

V

The Diffraction Parameter

Loss, dB

Diffraction losses at each obstruction, dB

L, dB

Diffraction losses, dB

Planning Point-to-Multipoint Networks

Planning Point-to-Multipoint network in MLinkPlanner, you can do:


1.    Different coverage study types for PtMP Base Stations
2.    Availability calculation for Base Station - Subscriber Station links

To calculate radio coverage, it is sufficient to enter the parameters of the base station(s) and the typical parameters of the subscriber station - “subscriber station installation,” which can be located anywhere in the study area.

For the point-to-multipoint link availability calculation (see Point-to-Multipoint Links Availability Calculation), it is also necessary to specify the location of each of the subscriber stations, specify to which base station each subscriber station relates, and enter all necessary detailed parameters of base stations and subscriber stations.

Figure 21. PtMP Network menu

First, it is necessary to include the specification file of the equipment family that is supposed to be involved in the project. 


Click on the Add a new product family button in the Point-to-Multipoint menu to include the product family to your project. To download the product family files from our website, click on the Download product family files button, and a link will open in the browser. We are continually updating the files with equipment parameters, but if such equipment not on our website, then first create the equipment specification file (see Equipment Editor).

Toolbar:

- Create a new PtMP base station


- Sort the base stations in alphabetical order


- Select / Unselect all BS sectors


- Delete all selected sectors; if all sectors of the BS are selected, that BS will also be deleted.


- Summary Report for all active Point-to-Multipoint links in MS Excel. Click the "Summary Report" button and an Excel spreadsheet will open. Only active base stations will be listed in the spreadsheet.

Tx power general limits for the PtMP network

BS Sector

not use

not use general limits for BS sector

limit Tx power to max level, dBm

Maximum Tx power for all BS Sectors in this project, dBm 
From the general limit that is set in this menu and the limit that is set in a particular BS Sector, the most stringent limit is selected in the calculations.

limit EIRP to max level, dBm

Maximum EIRP for all BS Sectors in this project, dBm 
From the general limit that is set in this menu and the limit that is set in a particular BS Sector, the most stringent limit is selected in the calculations.

Subscriber Station

not use

not use general limits for Subscriber Station

limit Tx power to max level, dBm

Maximum Tx power for all Subscriber Stations in this project, dBm 
From the general limit that is set in this menu and the limit that is set in a particular Subscriber Station, the most stringent limit is selected during the calculation.

limit EIRP to max level, dBm

Maximum EIRP for all Subscriber Stations in this project, dBm 
From the general limit that is set in this menu and the limit that is set in a particular Subscriber Station, the most stringent limit is selected during the calculation.

To create a base station, click on the Add button at the top of the Point-to-Multipoint menu, then select a site from the list that appears. After that, the Base Station will appear on the map, as well as the width of the angular sector and its direction. When creating a BS, one BS sector is always automatically created. You can add as many sectors for the BS as you need, just click the button.

Figure 22. PtMP BS Parameters

Toolbar:

- Add a new base station with the same parameters.


- Move this BS up.


- Move this BS down.


- Delete the base station.


- Change the site.


- Position the map with the base station at the center of the screen.


- Copy base station parameters to the clipboard


- Paste base station parameters from the clipboard

Figure 23. Base Station Sector Parameters

Toolbar:

- Add a new sector with the same parameters.


- Move the sector up.


- Move the sector down.


- Delete the sector.


- Select / Unselect all modulations and coding rows.


- Global active sectors parameter change - a feature that allows you instantly change the parameters of any base station in accordance with the parameters of the current sector.


- Position the map with the base station at the center of the screen.


- Add a new subscriber station for this sector.


- Sort the list of subscriber stations in the sector in alphabetical order.


- Generate the path profiles for all subscriber stations of the sector.

- BS Sector Performance Summary provides a summary of the performance of all the subscriber stations of the selected base station sector including the maximum usable modulation modes of all the PtMP Links that meet the required minimum flat fade margin setting and minimum annual availability setting.


- Display the product specifications for the selected bandwidth in the form of a datasheet, which can be saved in PDF, Word, or Excel formats.


- Copy sector parameters to the clipboard


- Paste sector parameters from the clipboard

In the drop-down lists, select the product family from those previously included to the project then select the equipment model (product), channel bandwidth, and frequency band. After that, general information about the selected equipment, its image, channel bitrates, and Tx power and Rx parameters for each supported modulation type will appear below.

Frequency, MHz

Azimuth, deg

Feeder loss, dB

Antenna Beam Tilt, deg

Antenna Height, m

Antenna Gain, dBi

Antenna Type

Antenna Pattern

Frequency of the BS sector, MHz

Antenna azimuth, degree

Feeder loss, default value is 0 dB

Antenna beam tilt, degree. A negative value is a downward beam tilt, a positive value - upward beam tilt.

Antenna installation height relative to ground level, m. You can also change the antenna height in the profile window

Antenna gain, dBi

Antenna model; information only.

To select antenna pattern, click the button next to the entered antenna model code and load the file in the *.msi or *.nsma format.

Tx Power Limitation

not use

Maximum Tx power limit, dBm

Maximum EIRP limit, dBm

not use Tx power max limit

Maximum Tx power for this BS sector, dBm From the general limit that is set in the PtMP menu and the limit that is set in this BS sector, the most stringent limit is selected during the calculation. 

Maximum EIRP for this BS sector, dBm 
From the general limit that is set in the PtMP menu and the limit that is set in this BS sector, the most stringent limit is selected during the calculation.

Global active sectors parameter change - this is a very convenient feature that allows you instantly change the parameters of any base station sectors in accordance with the parameters of the current sector. 


The procedure for performing group parameter changes on Multiple Base Station sectors:
1. Mark as active two or more base station sectors whose parameters need to be changed by clicking on the checkbox located to the left of the Base Station sector name.

 

2. Set the required parameter values in the current BS sector.

 

3. Click the button Global active sectors parameter change to display the Global active sectors parameter change pop-up menu. Select the parameters that need to be copied to the previously marked active BS sectors by clicking on the checkboxes in the sector parameter list. Click the OK button and the selected parameters will be copied to all base station sectors marked as active.

Figure 24. Global active base station sectors parameter change

Coverage Study

 

The coverage study calculates the estimated coverage of the base stations – i.e., the study approximately determines the areas where the subscriber stations can be located and gives a rough estimate of the achievable link capacity in this location. To ensure the correctness of the decision to place the subscriber station in a particular location, and to determine the exact height and type of the subscriber station antenna for the required link capacity, it is necessary to perform a detailed link availability calculation.


Coverage study is performed under the following conditions:


1.    The parameters entered for each of the base station sectors are used for the coverage calculation.
2.    A typical "Subscriber station installation" is used in the calculations for predicting coverage in the entire study area. The typical subscriber station parameters are entered into the Coverage Study Details menu.
3.    The calculations do not take into account the excess path loss due to clutter loss (buildings and trees).

 

Before starting a coverage area study, you must first specify the parameters of the base station sectors that will be involved in the study and set those base station sectors to Active. Refer to Base Stations section for information on setting base station parameters. Please note that the coverage study for base station sectors will only be carried out if the checkbox, located to the left of the base station sector name, is active.


To configure the Coverage Study options, go to the Coverage Study Details menu.

Figure 25. Coverage Study Details for Received Power at subscriber stations study

Coverage study Details

Area Study Type

Received Power at subscriber stations
Strongest (Most likely) Server
C/I+N at subscriber stations

Base Station Parameters

Transmit Power, dBm

Use BS Transmitter Power Data

Study Radius, km

Оne power value for all base stations, dBm

Use the power settings for each of the base stations specified in the BS sector menu.

Maximum study radius from Base Station, km

Subscriber Station Installation

Antenna Height, m

Antenna Gain, dBi

Feeder Loss, dB

Antenna installation height relative to ground level, m.

Antenna gain, dBi

Feeder loss, default value is 0 dB

Additional calculation parameters

Margin, dB

Low Resolution

High Resolution

Prediction confidence margin of the calculation results for area study, dB

Low-resolution calculation (less computation time)

High-resolution calculation (more computation time)

Received Power at Subscriber Stations

Received power map shows those areas where a given signal power level is present at the subscriber station’s receiver (downlink).

Number of Levels

Color

Values, dBm *

Description

The number of signal levels from 1 to 8

The color of the signal level

Received power level, dBm

The text field as an annotation on each signal level; for example, 256-QAM 5/6 400 Mbit/s

* To automatically fill these fields with subscriber station parameters, go to the panel of the characteristics of the subscriber station and click on the Copy selected Rx thresholds to Coverage Study Levels button. Then the threshold levels are copied to the Levels field and information about the selected modulation modes is copied to the Description field.

To perform the coverage study, click the           button.

Figure 26. Received Power at subscriber stations coverage

Best Server

Best server map display is a map showing the base station supplying the strongest received signal at all locations on the base map.

Figure 27. Coverage Study Details for Best Server study

Required Service Threshold, dBm

This is the minimum acceptable signal strength
required by the receiver.

Apply Automatic Color Assignment

The program automatically assigns colors to the base stations in the study and then color fills the map according to these color assignments.

Use Colors from the Table

Fill the Table with Frequencies of BS

The colors for the base stations will be assigned in accordance with the frequency table.

Fill the table with the frequencies specified in the parameters of the base stations.

Figure 28. Best Server study

C/(I+N) at Subscriber Stations

The carrier-to-interference + noise ratio, C/(I+N) or CIR, is one of the most important quantities used in assessing system performance. The quantity CIR is more completely written as:

where C is the power of the signal from the strongest server at a location, Ik is the power of each of the other k signals at that location, NR is the receiver noise power, and K is the total number of transmitters which cause interference at this location. Ik is only computed for transmitters that are using a co-channel or adjacent channel. If the closest channel in use by the interference sector is an adjacent channel, then the interference contribution by the sector is reduced in amplitude by the adjacent channel rejection factor. 


Channels are defined as adjacent if the difference between the center frequencies of the channels is less than or equal to one bandwidth. 


Channels are defined as co-channels if the difference between the center frequencies of the channels is zero.


The receiver noise power is calculated by multiplying the receiver effective noise bandwidth by the power noise density as represented by the receiver noise figure.


CIR is calculated by first finding the strongest received signal power from any transmitter at each location. It then calculates the sum of the received signal powers from all of the other transmitters which also have relevant signal levels at the location. After the sum of the interference is found, the noise power is calculated and the ratio is found.


Note that once the strongest signal has been identified, the directional received antenna at each location is assumed to be pointed toward the transmitter from which the strongest signal is received. The received signal from the other (interference) transmitters is then found using the off-axis gain of the received antenna, assuming an orientation toward the strongest signal transmitter.

Figure 29. Coverage Study Details for C/(I+N) at subscriber stations study

Required Service Threshold, dBm

This is the minimum acceptable signal strength
required by the receiver.

Browse MSI or NSMA

Use Adjacent Channel Interference

Adjacent Channel Rejection, dB

Channel Bandwidth, MHz

Use Receiver Noise Power Level

Receiver Noise Figure, dB

Equivalent Noise Bandwidth, MHz

Choose the antenna pattern file for Subscriber Station Installation in MSI or NSMA format.

If the checkbox is active, the calculation will take into account the contribution of adjacent channels to interference.

Adjacent channel rejection, dB

Channel bandwidth, MHz

If the checkbox is active, the calculation will take into account the power of receiver noise.

Receiver noise figure, dB

Equivalent noise bandwidth, MHz

If the checkboxes "Use adjacent channel interference" and "Use receiver noise power level" are not active, the calculations will take into account only the co-channel interference.

Figure 30. C/(I+N)  study

Creating a Coverage Report 

Coverage reports can be saved as an interactive web page, an image file, or a KMZ file.


         Save the coverage as a webpage – Saves as a webpage. The index.html file (this is a page script), the bs.png file (the base station icon), and the folder of the coverage tile pyramid in the format {Z} / {X} / {Y} will be saved to the folder selected by the user. To view the result, open the index.html file in any web browser. This page can also be placed on a web server for viewing in any browser and on any of the operating systems (Windows, Mac, iOS, Android, Linux).


The webpage allows you to:
- Choose a base map from four different base maps
- Change the map zoom
- Display the legend
- Display the map zoom and the map scale and current coordinates of the cursor (in the decimal system and DMS)

 

To view an interactive webpage, you need an Internet connection.
The folder with the pyramid of tiles can be connected to any GIS that supports working with tiles (i.e.: QGIS, ArcGIS, MapInfo), which will demonstrate the result of calculating the radio coverage as a layer on any GIS.

Figure 31. Example of the interactive webpage

           Save the coverage as an image - Saves the result of coverage calculation as an image file in *.png format.


Before saving the image, the user can select the area of the saved coverage using the appearing frame. In this case, you can move both the border of the frame and the map itself.


When saving an image, the user also selects its resolution. Resolution may correspond with the current size or be two or four times larger. The better the resolution, the larger the size of the saved file. The maximum size of the bitmap image is approximately 5400x4400 pixels; the file size in the *.png format is about 10 MB.


A scale bar appears in the lower-left corner of the saved image.

Figure 32. Save the coverage as an image

Save the calculation result as a KMZ file - Saves the calculation result as a KMZ file, which can be opened in Google Earth.

Figure 33. View KMZ file in Google Earth

Two Coverage Calculation Comparison

The program allows you to perform a visual comparison of the two results coverage calculation. Therefore, you can evaluate the effect on coverage of a change in various parameters of the base and subscriber stations of the PtMP network.


To add the performed calculation to the comparison, click the Add Coverage to Compare button on the top toolbar. Now, when you go to the Compare coverage menu of the main toolbar, this calculation result will be located on the left side of the screen. Whereas on the right side of the screen, the result of the current coverage calculation will be displayed. Now, for example, you can change the height of the sector or sectors of active BSs, and after performing the coverage calculation, you can see how these changes were reflected in the result compared to the previous calculation.


Manage maps in the left and right panels (map shift and zoom) independently of each other. It is convenient to perform this operation with the mouse by dragging and rotating the wheel. By controlling the maps in this way, one can compare in small details the two results of coverage calculating.

Figure 20. Coverage Study Details for Strongest Server

Figure 34. Two coverage calculation comparison

PtMP Subscriber Stations

For each of the Base Stations, you can set its Subscriber Stations. 


To create a subscriber station, click on the Add subscriber station button in the sector to which it will be linked. Then select the site from the list. After that, the subscriber station panel will open.

Figure 35. Subscriber station parameters

- Add a new subscriber station with the same parameters.


- Move the subscriber station up.


- Move the subscriber station down.


- Delete the subscriber station.


- Select / Unselect all modulations and coding rows.


- Change the site.


- Position the map with the subscriber station at the center of the screen.


- Generate the path profile to a base station.


- Link report


- Copy selected Rx thresholds to Coverage Study Levels.


- Display the product specifications for the selected bandwidth in the form of a datasheet, which can be saved in PDF, Word, or Excel formats.

In the drop-down list, select the equipment model (product). The equipment family for the subscriber station is the same as the Family specified for the BS sector. Below you will see general information about the selected equipment, its image, channel bitrates, Tx power and Rx parameters for each modulation type.

Feeder and Other Losses, dB

Antenna Height, m

Antenna Gain, dBi

Antenna Type

Feeder and connector losses; default value is 0 dB.

Antenna installation height relative to ground level, m. You can also change the antenna height in the profile window.

Antenna gain, dBi

Antenna model; information only.

Tx Power Limitation

not use

Maximum Tx power limit, dBm

Antenna Type

not use Tx power max limit

Maximum Tx power for this Subscriber Station, dBm 
From the general limit that is set in the PtMP menu and the limit that is set in this Subscriber Station, the most stringent limit is selected during the calculation.

Maximum EIRP for this Subscriber Station, dBm 
From the general limit that is set in the PtMP menu and the limit that is set in this Subscriber Station, the most stringent limit is selected during the calculation.

The antenna pattern for a subscriber station is not specified since it is always directed strictly in the direction of the BS sector to which it is linked. The frequency also coincides with the BS sector frequency.


It is also convenient to create subscriber stations using the context menu on the base map. To do this, follow these steps:


1. In the main menu, select the BS sector to which the new subscriber station will be linked. You can also select the BS sector directly on the map by double-clicking on the degree designation of the desired BS sector.


2. Right-click on the site for the subscriber station and select “Create Subscriber Station Site Name” in the context menu.


3. If you right-click on a subscriber station that has already been created, an additional line will appear in the context menu: “Delete all subscriber stations associated with the Site Name site,” with which you can delete a subscriber station. Notice that you delete only the subscriber station, not the site that connected to it.

Point-to-Multipoint Link Availability Calculation

For each of the Base Station - Subscriber station links can be performed availability calculation with a detailed consideration of all clutters along with the path profile. This calculation enables you to choose the parameters of the antennas and equipment for each link.

To generate a report:


1.    Create a Base and Subscriber Station (see the relevant sections).


2.    In the parameters panel of the corresponding subscriber station, use the Generate the path profile to a base station. button to create a path profile between the base and subscriber stations. All of the possibilities when working with the path profile for PtMP are the same as when working with the profile for point-to-point links.


3.    Use the Link Report button to create a report; in this case, you can select the required report type - Short report or Full report.

Figure 36. PtMP link full report in PDF

Figure 37. BS Sector Performance Summary

BS Sector Performance Summary provides a summary of the performance of all the subscriber stations of the selected base station sector including the maximum usable modulation modes of all the PtMP Links that meet the required minimum flat fade margin setting and minimum annual availability setting.

Figure 38. MS Excel Summary Report for Point-to-Multipoint links

Click the "Summary Report" button on the PtMP menu and an Excel spreadsheet will open. Only active base stations will be listed in the spreadsheet.

In the point-to-multipoint link availability calculation, all clutter (buildings and trees) along the path profile are taken into account.

For point-to-multipoint links, the same path profile analysis features as for the point-to-point path profile available:

  • Antenna minimum height calculation

  • Reflection Analysis

  • Diffraction Analysis