Harmful Interference and Its Role in Spectrum Policy

Radio spectrum has been subject to national and international regulation almost from its earliest days. “Harmful interference” is a key concept used by regulators in determining whether the impact of a proposed change in permitted radio use is acceptable vis-á-vis incumbent users. While the definition of harmful interference may have been adequate when it was first adopted decades ago, modern radio technology results in many situations where the definition is ambiguous. Clarifying the concept may improve regulatory certainty for developers of new radio technology while also improving the protection of incumbent users.