Chapter 10 Detection of Spread-Spectrum Signals

Abstract

The ability to detect the presence of spread-spectrum signals is often required by cognitive radio, ultra-wideband, and military systems. This chapter presents an analysis of the detection of spread-spectrum signals when the spreading sequence or the frequency-hopping pattern is unknown and cannot be accurately estimated by the detector. Thus, the detector cannot mimic the intended receiver, and alternative procedures are required. The goal is limited in that only detection is sought, not demodulation or decoding. Nevertheless, detection theory leads to impractical devices for the detection of spread-spectrum signals. An alternative procedure is to use a radiometer or energy detector, which relies solely on energy measurements to determine the presence of unknown signals. The radiometer has applications not only as a detector of spread-spectrum signals, but also as a sensing method in cognitive radio and ultra-wideband systems.