噪声功率不确定性区间估计和降低SNR WALL恶化的能量检测算法
doi: 10.3724/SP.J.1146.2013.00928
Estimation of Noise Power Uncertainty Interval and Energy Detector with Lowering SNR WALL Deterioration
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摘要: 能量检测是认知无线电系统中广泛采用的空闲频谱检测方案，但其性能受到噪声功率不确定性(NPU)的严重影响。该文提出一种新颖的复杂度较低的NPU区间估计算法，并且从理论上分析了估计的噪声功率对能量检测信噪比墙(SNR WALL)恶化的影响，得出了SNR WALL恶化性定理。进一步基于门限修正提出一种改进的能量检测算法以消除SNR WALL恶化。仿真结果表明，该算法能较为精确地估计NPU区间，并且验证了SNR WALL恶化性定理的正确性；同时，改进的能量检测算法性能要优于稳健的统计方案(RSA)能量检测的结果，并且改进后降低了SNR WALL恶化，提高了检测的鲁棒性。
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关键词:
- 认知无线电 /
- 噪声功率不确定性(NPU) /
- NPU区间估计 /
- 信噪比墙恶化 /
- 能量检测
Abstract: 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. -
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