Energy Detection

Energy detection is a common signal detection method that determines the presence of signals by measuring their energy levels. This approach represents a relatively simple yet effective detection technique applicable across various domains including communications, radar systems, and radio frequency applications. In communication systems, energy detection can identify whether a channel contains signal transmission while assessing signal strength and quality through threshold comparison algorithms. In radar applications, this method enables target presence detection and facilitates distance/speed calculations using energy-based feature extraction. For radio frequency applications, energy detection assists in noise and interference identification while determining signal sources and types through spectral analysis. From an implementation perspective, energy detection typically involves calculating the received signal power over a specific observation window and comparing it against a predetermined threshold. The core algorithm can be expressed as: T = Σ|r[n]|², where T represents the test statistic, r[n] denotes received signal samples, and the detection decision is made by comparing T with a threshold γ derived from noise variance estimates. This method's simplicity makes it computationally efficient, though performance depends heavily on accurate noise power estimation and proper threshold selection techniques.