The Information Theoretic Approach to Signal Anomaly Detection for Cognitive Radio
Figure 7
(a) Message exchange between a mobile terminal and a base station using the WiBro communications protocol. An extra command sequence in the uplink subframe at ms initiates the power control loop. (b) The extra command sequence ( ms) and subsequent power change ( ms) are both revealed by KLD/L1D analyses of the signal. A larger KLD peak results from the anomalous command but not from the power change. L1D also leads to larger noise levels compared to KLD.
