Cooperative Spectrum Sensing via Belief Propagation in Spectrum-Heterogeneous Cognitive Radio Systems

In a heterogeneous cognitive radio system, different secondary users may suffer from different activities of primary user, thus making a joint cooperative spectrum sensing difficult. However, there typically exists strong correlation among secondary users located close to each other, which can substantially benefit the spectrum sensing. To leverage the correlation, belief propagation (BP) is applied for cooperative spectrum sensing in heterogeneous cognitive radio systems. Simplifications and assumptions are proposed to facilitate the message computing and passing in BP. Numerical results show that the BP based cooperative spectrum sensing can significantly improve the performance over single-user spectrum sensing using only a few iterations. Simulation also shows that the performance is insensitive to the knowledge of mutual distance between secondary users, as well as the number of bits used to quantize beliefs, the communication range and packet loss.