高斯白噪声的VHDL实现。伪随机序列只能输出均匀噪声，需要打乱相关性。-awgn in vhdl

In this paper we uate the performance of cooperative spectrum sensing (CSS) where each cognitive radio (CR) employs an improved energy detector (IED) with multiple antennas and uses selection combining (SC) for detecting the primary user (PU) in