Architectural Opportunities for Novel Dynamic EMI Shifting(DEMIS)

Processors emit non-trivial amounts of electromagnetic radiation, creating interference in frequency bands used by wireless communication technologies such as cellular, WiFi and Bluetooth. We introduce the problem of in-band radio frequency noise as a form of electromagnetic interference (EMI) to the computer architecture community as a technical challenge to be addressed. This paper proposes the new idea of Dynamic EMI Shifting (DEMIS) where architectural and/or compiler changes allow the EMI to be shifted at runtime. DEMIS processors dynamically move the interference from bands used during communication to other unused frequencies. Unlike previous works that leverage static techniques, DEMIS dynamically targets specific frequency bands; the type of techniques used here are only possible from an architectural perspective. This paper is also the first to provide insights in the new area of dynamic EMI shifting by evaluating several platforms and showing the EMI is sensitive to many architectural and compilation parameters. Our evaluation over real systems shows a decrease of in-band EMI ranging from 3 to 15 dB with less than a 10% average performance impact. A 15dB EMI reduction for LTE can represent over 3x bandwidth improvement for EMI bound communication.