应用定向天线测量无线信道角度功率谱

Estimation of power azimuth spectrum for wireless channel using directional antenna measurements

针对无线信道角度功率谱测量问题,提出了一种简单而新颖的测量方法。利用定向天线进行方位角扫描的功率测量,观测值、天线方向图和角度功率谱之间构成第一类Fredholm积分方程,通过求解积分方程可以得到角度功率谱。利用低通滤波器对观测数据进行预处理可以克服解积分方程的病态问题,改变滤波器参数并结合最小均方误差准则,可以得到角度功率谱的最小均方误差估计。仿真结果验证了该方法的有效性。

A novel method for estimating power azimuth spectrum （PAS） of wireless channel is presented in this paper. Based on azimuth-scanning power measurements by using directional antenna, a Fredholm integral equation of the first kind can be constructed from the mesurmed data, the antenna pattern and the PAS. The estimations of PAS can be achieved by solving the integral equation. The ill-conditioned problems can be overcome by pre-processing the observed data by employing a lowpass filter. The minimum mean square error （MMSE） estimation of PAS can be achieved by selecting the proper parameters of the lowpass filter based on the MMSE criterion. Simulation results show that the method presented is effective.