Robert J. Achatz and Brent L. Bedford

Abstract: Interference protection criteria (IPC) determine the interfering signal power a system can tolerate when sharing spectrum with other services. IPC are typically determined by measurements, but good measurements are often hindered by restrictions on equipment availability and inaccessible intermediate signals, performance metrics, and operational parameters. The purpose of this research is to determine if radio system software simulation can accurately emulate these measurements and alleviate their hindrances. Our approach is to use commercial off-the-shelf (COTS) radio system simulator software to model previous IPC measurement test fixtures and compare simulated to measured results. Measurements of mutual interference between SPN-43C radar and LTE systems are compared. The comparison revealed that 1) when the SPN-43C pulse repetition interval was the same as the LTE subframe period SPN-43C interference in the LTE UE was highly dependent on which OFDM word within the LTE subframe the SPN-43C pulse was repeatedly placed on and 2) simulation is more accurate than measurement for IPC tests with fixed threshold radars such as SPN-43C. These revelations show that simulation is a useful addition and potentially viable alternative to IPC measurement.

Keywords: spectrum engineering; spectrum sharing; electromagnetic compatibility (EMC) analysis; Long Term Evolution (LTE); interference protection criteria (IPC); Citizens Broadband Radio Service (CBRS); radio system software simulation; surveillance radar

Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

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