Combat radio system range reduction due to radiated electromagnetic interference from COTS electronics

Co-location between digital radio systems and civilian electronic equipment can lead to severe interference problems. Unintentional radiated electromagnetic emission can increase the bit error probability (BEP) in the digital radio receiver, and thus reduce the range of secure operation. Furthermore the intersystem interference causes a reduction of the jamming resistance. In this paper, the corresponding decrease of the operating range to compensate for this increase in BEP is determined Furthermore, the increase of the operating range for a hostile jammer is determined for a chosen example. The results are visualized as simulated coverage diagrams for chosen terrain environments. The analyses show that the operating range is decreased with approximately 25% for a co-location distance of 20 meters between the radio receiver and disturbing COTS (commercial of the shelf) equipment, if typical measured emission levels are used. In this scenario a hostile jammer gets nearly 50% larger operating range compared to a scenario without the COTS-computers. If a part of the emission equals the EN 55022 Class B emission limit, required for commercial equipment sold in the European Union, a range reduction of 50% is obtained. Thus, the overall conclusion is that interference from COTS can cause severe reductions of operating range for digital communication links. This interference can also have significant impact on the jamming resistance. These are important drawbacks that must be considered before co-locating COTS equipment close to tactical communication systems.