Cooperative wideband spectrum sensing for cognitive radio networks in fading channels

Spectrum sensing is an essential capability that allows the cognitive radios (CRs) to detect spectral holes and opportunistically use underutilised frequency bands without causing deleterious interference to primary users. In this study the authors address two cooperative wideband spectrum sensing techniques for the frequency-selective and frequency-non-selective fading channels in which the primary user signals are detected over multiple frequency bands. The primary user signals, indices and the number of occupied subbands, the channels characteristics and the noise variance of the secondary receivers (SRs) are considered to be unknown. Thus, the problem of spectrum sensing in the fusion centre is modelled by a composite testing hypothesis in time domain and using generalised likelihood ratio (GLR) test the spectral holes are detected. In the frequency-selective case the authors have decreased the computational complexity using some approximations. Simulation results show that the proposed spectrum sensing schemes achieve satisfactory performance and also are robust against the SRs arrangement in the CR network.