two_doppler_spead.m

多径多普勒信道模型

clear;
t=(0:0.01:10);an=[1,0.3,-0.8,0.5,-0.4,0.2];wn=[0,2,10,6,8,4];
for i=1:6;
s1(i,:)=an(i)*exp(j*0*wn(i))*[ones(1,501),zeros(1,500)];
s2(i,:)=an(i)*exp(j*0.02*wn(i))*[ones(1,501),zeros(1,500)];
end
y1(1,:)=sum(s1);y2(1,:)=sum(s2);wn1=[0,20,100,60,80,40];
for k=1:6;
s3(k,:)=an(k)*exp(j*0*wn1(k))*[ones(1,501),zeros(1,500)];
s4(k,:)=an(k)*exp(j*0.02*wn1(k))*[ones(1,501),zeros(1,500)];
end
y3(1,:)=sum(s3);y4(1,:)=sum(s4);
subplot(2,1,1);
plot(t,abs(y1));ylabel('y(t)'); xlabel('Time(us)');
title('case 1: small Doppler spread')
ylim([-0.2 2.2]);hold on;
plot(t,abs(y2),'r');hold off
legend('t_0=0msec','t_0=20msec')
subplot(2,1,2);
plot(t,abs(y3));xlabel('Time(us)');ylabel('y(t)');
title('case 2: large Doppler spread')
ylim([-0.2 2.2]);hold on;
plot(t,abs(y4) ,'r');hold off
legend('t_0=0msec','t_0=20msec')