Cognitive radio system with advanced environment awareness engine using integrated propagation models and multiple antennas

摘要

Cognitive radio systems adaptively adjust their radio parameters based on the feedback from the electromagnetic environment. Therefore, it is expected that cognitive radio systems will have better performance if they are integrated with accurate site-specific propagation modeling. Our group has long standing expertise in propagation modeling utilizing geo-spatial tools and indoor building models, and has focus on integrating these models as part of the environment awareness engine in cognitive radios. In this paper, we present the preliminary results for a multi-antenna based spectrum sensing algorithm with adaptive thresholds. The results show that, an almost fixed detection rate of 85% can be achieved for a mobile cognitive radio in an urban environment when the thresholds are set based on the path loss information provided by site-specific propagation modeling. On the other hand, the spectrum sensing algorithm with a fixed threshold shows a great variability in the detection performance, going as low as 65% in regions with heavy fading, which leads to harmful interference.