www.gusucode.com > CDMA小区中断概率仿真源码程序 > CDMA小区中断概率仿真源码程序/源程序/wilkinson.m
function [m_out,std_out] = wilkinson(m_x,std_x,r) % % This function computes the mean and standard deviation % of the sum of two lognormal RV's. % Input and ouput values are in dB. % lambda = 0.1*log(10); m_x_cmp = m_x; v_x_cmp = std_x.^2; m_y = lambda*m_x_cmp; v_y = (lambda^2)*v_x_cmp; u_1 = 0; for i = 1:length(m_y) u_1 = u_1 + exp(m_y(i) + v_y(i)/2); end a = 0; for i = 1:length(m_y) a = a + exp(2*m_y(i) + 2*v_y(i)); end b = 0; for i = 1:length(m_y)-1 for j = i+1:length(m_y) b = b + exp( m_y(i) + m_y(j) )*... exp(0.5*(v_y(i) + v_y(j) + ... 2*r*sqrt(v_y(i))*sqrt(v_y(j)))); end end u_2 = a + 2*b; % % mean and variance or the variable Z, which is normal in natural units % m_z = 2*log(u_1) - 0.5*log(u_2); std_z = sqrt(log(u_2) - 2*log(u_1)); % % mean and variance of the variable X, which is normal in dB. % g = 10*log10(exp(1)); m_out = g*m_z; std_out = g*std_z; % End of function file.