Behind every wireless telecommunications decision is a prediction of how far the signal will travel and how much strength it will lose along the way. This is called propagation modelling. Propagation models drive decisions about things like how and where to deploy cell towers, what rules to establish for geographically sharing spectrum, and what kind of spectrum equipment to build. It is vital that all stakeholders trust the models being used and accept the results as sound.

This month, NTIA’s Institute for Telecommunication Sciences [1] (ITS), the nation’s spectrum and communications lab, released a new official code base for the Irregular Terrain Model (ITM) for use by experts and non-experts alike.

The Federal Communications Commission Report and Order [2] opening the 6 GHz band to Wi-Fi and other unlicensed uses requires that ITM be used by the automated frequency coordination  system designed to protect incumbents from commercial entrants. Under the Commission’s ruling, at specific distances ITM must be used with an appropriate clutter model as one of the factors when determining exclusion zones to protect incumbent services.

ITM is the fifth propagation model code base that ITS has released on GitHub. In addition to the C++ propagation model source code, ITS published packages that target the .NET development environment. ITS also code signs its propagation software. Users can be confident that our products originate with us, and have not been tampered with.

This work is another in a long line of ITS’s industry leading research [3] on propagation modelling. ITS is committed to not only providing world class propagation models, but also to ensuring the availability of digital products whose integrity can be assured, that can be consumed by a large variety of applications and tools, and that can be utilized by experts and non-experts alike.

List of ITS open source propagation model software on GitHub:

• LFMF [4]: Low Frequency / Medium Frequency (LF/MF) Propagation Model
• ehata [5]: The Extended Hata (eHata) Urban Propagation Model
• p528 [6]: U.S. reference implementation of ITU-R Recommendation P.528 providing propagation path loss predictions for aeronautical mobile and radionavigation services using the VHF, UHF, and SHF bands
• if77-gierhart-johnson [7]: IF-77 Air-to-Ground Propagation Model (Gierhart-Johnson)
• ITM [8]: Irregular Terrain Model (Longley-Rice)

To view other available models, visit our ITS site [9].