Understanding Spectrum Clutter—It’s Not About Neatness!

The National Telecommunications and Information Administration's Institute for Telecommunication Sciences (ITS) has been working to better understand how to factor in clutter when analyzing and predicting the behavior of radio waves.

ITS engineer Chriss Hammerschmidt presented a paper earlier this week on "Extracting Clutter Metrics From Mobile Propagation Measurements in the 1755-1780 MHz Band" at MILCOM 2016, an international conference for military communications. The paper describes spectrum measurements ITS took during 2015 to inform and validate new radio wave propagation prediction models. Propagation models, mathematical algorithms that predict the behavior of radio waves, are an essential enabler for spectrum sharing. ITS and its predecessor labs within the Department of Commerce have been developing and improving propagation models since about 1909. But increased demand for spectrum, advances in technology, and the tremendous increase in the everyday spectrum usage (sometimes referred to as the "noise floor"), means that there are tremendous potential benefits from more research and testing to improve the accuracy of existing propagation models. As the telecommunications industry moves into the future with new technologies like 5G, ever more detailed models of clutter loss will be required to facilitate spectrum sharing.

This set of measurements is a first step on the path to making spectrum sharing as efficient as possible. Tremendous opportunities remain, however, for investment in propagation research and testing to achieve even greater efficiencies in our use of limited spectrum resources.