Spectrum sensing for spreading communication system based on free probability theory

Based on free probability theory, a new scheme for frequency band sensing of spreading communication system is proposed. Unlike previous studies in the field, the new scheme does not require the knowledge of the spreading sequences of users and is related to the asymptotic free behavior of random matrices. Simulation result shows that the convergence characteristic holds true even for a small number of observations, which makes the new scheme well suited for realistic time-varing scenario. The sensing performance of new scheme is also much better than that of classical energy detection scheme.