Full-Duplex Spectrum Sensing and Access in Cognitive Radio Networks with Unknown Primary User Activities

In this paper, we consider the problem of optimal opportunistic spectrum access using full-duplex (FD) radios in presence of uncertain primary user (PU) channel statistics and propose a Sensing-and-Selectively-Transmit protocol (SaST). To optimize its throughput, the SU sensing period has to be carefully tuned. However, in absence of the exact knowledge of PU activity statistics, under SaST, the PU's performance may be adversely affected. A learning strategy is devised to update the estimated statistics based on spectrum sensing observations. Simulation studies demonstrate that the resulting robust solution provides a good trade-off between optimizing the SU's throughput and protecting the PU.