Cognitive Radio Network as Sensors
Cognitive radio network as sensors is a new initiative and tries to explore the vision of a dual-use sensing/communication system based on cognitive radio network [1331–1333]. The motivation of cognitive radio network as sensors is to push the convergence of sensing and communication systems into a unified cognitive networking system. Cognitive radio network is a cyber-physical system with the integrated capabilities of control, communication, and computing. Cognitive radio network can provide an information superhighway and a strong backbone for the next-generation intelligence, surveillance, and reconnaissance.
Multifunctional SDRs for both radar and communication have been studied in [1334–1337]. OFDM waveform is explored. OFDM is the core technology in wideband communication. OFDM is adopted by 3GPP LTE, WLAN, power line communication, cognitive radio , as well as ADSL and VDSL. The OFDM waveform has also been used in the radar society [1338–1341]. The key feature of the OFDM waveform is that multiple frequencies can be exploited simultaneously and in an orthogonal way. Meanwhile, the radio resources of all frequencies in OFDM waveform can be adjusted dynamically. The advantages of using OFDM in radar have also been summarized in . Digital generation, inexpensive implementation, pulse-to-pulse shape variation, interference mitigation, noise-like waveform for low probability of intercept/detection (LPI/LPD), and so on ...