模拟aloha协议

clear
G = 5:0.01:0.1;
n=length(G);
t0=0.5;
i=0;
u=0;
b=0;
tb = 0;
tu=0;
ti=0;
for j = 1:length(G)
r = exprnd(G(j),1,n);
if r(j)<t0
    b=b+1;
    tb = r(j)+t0;
elseif r(