Implementation of Real-Time Spectrum Handoff with Blind Cooperative Spectrum Sensing for Cognitive Radio using Software-Defined Radios

As the demand for frequency resources increases due to the current trends in technology such as IoT and smart cities, efficient spectral usage becomes a prerequisite. To improve spectral efficiency, many studies have proposed cognitive radio (CR) as a solution. CR is mainly composed of two parts: spectrum sensing, which allows continuous identification of spectrum holes, and spectrum handoff, which ensures the cognitive user (CU) vacates the channel when a primary user (PU) becomes active. This study implemented a CR system with both spectrum sensing and handoff capabilities using the ADALM Pluto Software-Defined Radio (SDR) and GNU Radio. For spectrum sensing, we used cooperative blind spectrum sensing (BSS) techniques, specifically energy detector and the covariance-based detector. For spectrum handoff, a probabilistic scheme was used and compared with a traditional reactive scheme. The performance of the implemented system was evaluated in both an open area and a full anechoic chamber. It was observed that both energy and covariance-based detectors were able to detect PU activity accurately, but the latter was able to sustain its performance at a lower signal-to-noise ratio (SNR). For spectrum handoff, two setups were done: one in the open area utilizing Wi-Fi and LTE bands, and another in the anechoic chamber to enable CU transmission. Results also show that the probabilistic scheme had better performance in handoff latency and throughput than a reactive scheme.