Secure cooperative spectrum sensing in cognitive radio networks using interference signatures

Cooperative spectrum sensing has received considerable attention as a viable means to enhance the detection performance by exploiting spatial diversity in received signal strengths. However, this is vulnerable to sensing data falsification attacks due to the distributed nature of cooperative spectrum sensing. To overcome this problem, we introduce a primary user emulation test (PUET), under which a trustful central entity (e.g., a cellular base station) transmits a test signal while other users are sensing the spectrum. The core of PUET is to correlate the reported sensing data with the transmission power of the test signal. Since this test signal is, in reality, an interference to the sensing of a primary signal, sensors cannot distinguish the test signal from the primary signal. Considering this characteristic of sensors, PUET detects attacks by evaluating the consistency of channel parameters, which are not known to sensors. By recognizing this defense mechanism, PUET checks the validity of reports from each sensor separately. The efficacy of PUET is validated via experimentation on a testbed deployed in an indoor environment. Our measurement study shows that PUET achieves over 95% detection rate while keeping the false alarm rate under 5%.