Estimation of Noise Power Uncertainty Interval and Energy Detector with Lowering SNR WALL Deterioration

Energy Detector (ED) is the most common way of idle spectrum sensing in cognitive radio. However, its performance may suffer seriously from the Noise Power Uncertainty (NPU). In this paper, a low computational algorithm is proposed to estimate the NPU interval, and the SNR WALL deterioration phenomenon with estimated noise power is analyzed theoretically. The SNR WALL deterioration theorems are obtained. In addition, a new ED algorithm based on modified threshold is proposed to eliminate SNR WALL deterioration. Numerical simulation results show that the proposed algorithm can estimate accurately the NPU interval, and verify the correctness of the SNR WALL deterioration theorems. Furthermore, both analytical and simulation results show that the proposed ED under NPU outperforms the ED of Robust Statistics Approach (RSA). The SNR WALL deterioration can be reduced effectively, hence improving the robustness of detection.