最佳接收机的MATLAB

二元调制最佳接收机的MATLAB仿真程序

%bicomsim.m

close all

clear all

%P0 = 0.5;

%P1 = 0.5;

%fs = N/Tb

N = 10;

L = 1000;

k0 = 2;

Th1 = 0;

A = 1;

rand('state',sum(100*clock));

for db = -5:15,

r = 10^(db/10);

sigma = 0.5*A*sqrt(N)/10^(db/20);

i0 = db+6;

Pe0PSK(i0) = 0.5*erfc(sqrt(r));

Pe0ASKa(i0) = 0.5*erfc(sqrt(r/2));

Pe0ASKb(i0) = 0.5*erfc(sqrt(r/4));

Pe0FSK(i0) = Pe0ASKa(i0);

Th = 0.5*0.5*A^2*N;%2ASK

count = 0;

for j=1:L;

for i=1:N,

NN(i) = sigma*randn(1,1); %N(m, sigma)

s0(i) = 0;

s1(i) = A*sin(2*pi*k0*i/N);

x0(i) = s0(i) + NN(i);

x1(i) = s1(i) + NN(i);

end

summ0 = 0;

for i=1:N,

summ0 = summ0 + x0(i)*s1(i);

end

summa = summ0;

if summa > Th,

count = count + 1;

end

summ0 = 0;

for i=1:N,

summ0 = summ0 + x1(i)*s1(i);

end

summb = summ0;

if summb < Th,

count = count + 1;

end

end

PeASK(i0) = 0.5*count/L;

Th = 0; %2PSK

count = 0;

for j=1:L;

for i=1:N,

NN(i) = sigma*randn(1,1);

s0(i) = A*sin(2*pi*k0*i/N); Th = 0;

s1(i) = -A*sin(2*pi*k0*i/N); %2PSK

x0(i) = s0(i) + NN(i);

x1(i) = s1(i) + NN(i);

end

summ0 = sum(x0.*s0);

summ1 = sum(x0.*s1);

summa = summ0 - summ1;

sma(j) = summa;

if summa < Th,

count = count + 1;

end

summ0 = sum(x1.*s0);

summ1 = sum(x1.*s1);

summb = summ0 - summ1;

smb(j) = summb;

if summb > Th,

count = count + 1;

end

end

PePSK(i0) = 0.5*count/L;

Th = 0.5*0.5*A^2*N; %2FSK

count = 0;

for j=1:L;

for i=1:N,

NN(i) = sigma*randn(1,1);

s0(i) = A*sin(2*pi*k0*i/N); Th = 0;

s1(i) = A*sin(2*pi*(k0+1)*i/N);

x0(i) = s0(i) + NN(i);

x1(i) = s1(i) + NN(i);

end

summ0 = sum(x0.*s0);

summ1 = sum(x0.*s1);

summa = summ0 - summ1;

sma(j) = summa;

if summa < Th,

count = count + 1;

end

summ0 = sum(x1.*s0);

summ1 = sum(x1.*s1);

summb = summ0 - summ1;

smb(j) = summb;

if summb > Th,

count = count + 1;

end

end

PeFSK(i0) = 0.5*count/L;

end

i=1:21;

i2=i-6;

semilogy(i2,Pe0PSK,'b',i2,Pe0ASKb,'b',i2,Pe0FSK,'b');

hold on

semilogy(i2,PePSK,'r*',i2,PeASK,'ro',i2,PeFSK,'r+')

axis([-5 15 1.0e-06 1.0e0])