假定 f=800MHz,hm=1.5m,hb=30m,hroof=30m,平顶建筑， =90， =15m。比较 Walfish 模型和 Hata 模型的预   测结果（设收发距离为 1km~5km，步长为 200m)。 代码：clc; clear all; d=[1:0.2:5]; %km %---Okumura-Hata Urban loss ------------------------------------------- fc = 800; % MHz hb = 30; % m hm = 1.5; % m a = (1.1*log10(fc)-0.7)*hm -(1.56*log10(fc)-0.8); % 移动台天线高度修正因子 A = 69.55 + 26.16*log10(fc) - 13.82*log10(hb) - a; B = 44.9 - 6.55 *log10(hb); Lp1 = A +B*log10(d); plot(d, Lp1,'b-'); grid xlabel('距离 /km') ylabel('路径损耗 /dB') %---Walfisch-lkegami Urban loss ------------------------------------------- fc = 800; % MHz hb = 30; hm = 1.5; w = 15; hr = 30; % m % m %m %m b = 40; %沿无线路径的建筑物之间的距离取40 angle = 90; Lf = 32.4 + 20*log10(d) + 20*log10(fc); %自由空间损耗 L0 = 4 - 0.114*(angle-55); C = -16.9 - 10*log10(w) + 10*log10(fc); Lr = C + 20*log10(hr - hm) + L0; %楼顶至街道的绕射损耗 Kf = 0.7*(fc/925 - 1); Ka = 54; %d>=500且hb=hr Kd = 18; Lm = Ka + Kd*log10(d) + Kf*log(fc) - 9*log(b); %多重屏障的绕射损耗 LP2 = Lf + Lr + Lm; hold on plot(d, LP2, 'g-'); title('Okumura-Hata模型路径损耗与Walfisch-lkegami模型路径损耗对比'); legend('Okumura-Hata模型路径损耗','Walfisch-lkegami模型路径损耗'); hold off