相关阴影衰落的非相关近似

Decorrelated Approximation for Correlated Shadowing Fading

为了简化多个对数正态随机干扰的问题,提出了1种等效方法,将相关随机变量之和等效为非相关随机变量的和.根据此方法,干扰存在阴影相关性时,只需简单地对阴影标准差进行修正,就可按非相关模型进行分析研究或者搭建仿真平台.导出了相应的标准差修正公式.修正后非相关的阴影标准差较相关时变大,而且随着相关系数和干扰源个数的增加而增大.在Sφrensen相关模型下,通过对累积分布函数和中断率的仿真验证了这种近似方法的有效性.

To simplify the problem of multiple lognormal random interferences, an equivalent method is proposed to approximate the sum of correlated random variables to the sum of uncorrelated ones. With this approximation, the theories based on uncorrelated shadowing model can be used to analyze and simulate the system performance in the presence of multiple correlated lognormal interferers by simply modifying the standard deviation of lognormal shadowing. The formula to modify the standard deviation is derived. The modified standard deviation is generally larger than the original one and increases with the correlation coefficient between lognormal interferers and with the number of interferers. With the Sφrensen correlation model, the validity of the approximation method has been verified by simulation of both the cumulative distribution function of the total interference and the outage probability.