Multi-link Studies

It is common to have a system or environment consisting of several links, either as a multi-hop system stretching across a great distance, or in a metropolitan area where several links co-exist in the same frequency band. For such circumstances, it is essential to be able to analyze potential interference between links in such systems or environments. The multi-link study is intended for that purpose.

Selecting Studies>Multi-link Studies opens the Multi-Link System Studies dialog box where you can select several parameters to control your study results.

The first step is to select the Link Group that you intend to study (discussed in the Link Systems article). By defining link groups, you can choose to study selected portions of the system separately if desired. The list below the group selection will show a list of all the bi-directional links that are in the group.

In the Group/Link Creation section, you can set the Multi-Link study to create a new link group from those links that meet the criteria you enter for either C/(I+N) or Fresnel zone clearance. Groups created here are placed in the group list under RF Systems>Link Systems.

Click the Report Settings button to configure the amount of detail included in the Multi-Link report. You may then choose to do performance and interference studies for all the links at once or for just a single link in the presence of others in the group. If you want to study just a single link, you must first select it from the link list, then click on the Study selected link(s) button. To study all links at once, click the Study active link(s) button. The program will then go through the process of first evaluating the performance of each individual link. It will then analyze all the cross-link paths (every interfering transmitter to every victim receiver). The interfering power is then calculated using: those path loss values, the ERP from the interfering transmitter in the direction of the victim receiver, and the gain of the victim receiver antenna in the direction of the interfering transmitter. The interference from all other links is summed and then used to calculated the C/(I+N) ratio and availability performance of each victim link. The calculation will also take into account the operating frequency, receiver bandwidths, and noise figures for each interferer and victim receiver, as specified in the Link details dialog box for each link in the study.

Once the ‘Study complete’ message appears, you can click the Save Report button to save a text-only report. You can also print a full report including the link profiles to a printer or PDF print driver using the Print Setup and Print buttons. There is also an option to print (Write PDF) a pdf report which shows a Multi-link chart and Tx/Rx information for the selected Link ID.