clear;
clc;
tic;
%------------------
Tc=8;%快跳频每个切片的周期，即跳频驻留时间,对于快跳频，要求fs>2*(deltaf/2+1/Tc),且fs=N/Tc
N=1;%每符号多少跳；
h=1;%调制指数
len=100000;%仿真的数据长度
snj=4:2:12;
p=1;
%------------------
Tb=Tc*N;%每符号Tc/Tb跳；
deltaf=h/Tc;%2FSK信号的调制指数最小为1；
tt=0:Tc-1;
signal_chip_0=exp(-j*pi*deltaf*tt);
signal_chip_1=exp(j*pi*deltaf*tt);
signal_chip0_dem=conj(repmat(signal_chip_0.',1,N));
signal_chip1_dem=conj(repmat(signal_chip_1.',1,N));
%----------------------
Eb=1*Tb;
snj2=10.^(snj/10);
Nj=Eb./snj2;
sigma=sqrt(Nj/2);
%---------------------
bitsrc=randint(1,len);
bitrec=zeros(1,len);
signal=zeros(1,Tb);
l_snj=length(snj);
errbits=zeros(1,l_snj);
errrate=zeros(1,l_snj);
r0=zeros(Tc,1);
r1=zeros(Tc,1);
for kk=1:len
randph=exp(j*2*pi*(rand(1,N)));
if bitsrc(kk)==0
signal=kron(randph,signal_chip_0);
else
signal=kron(randph,signal_chip_1);
end;
% subplot(2,1,1);
% plot(real(signal));
% subplot(2,1,2);
% plot(imag(signal));
noise=randn(1,Tb)+j*randn(1,Tb);
for nn=1:l_snj
recv=signal+sigma(nn)*noise;
recv2=reshape(recv,Tc,N);
r0=abs(sum(recv2.*signal_chip0_dem)).^p;
r1=abs(sum(recv2.*signal_chip1_dem)).^p;
if sum(r0)>=sum(r1)
bitrec(kk)=0;
else
bitrec(kk)=1;
end;
if bitrec(kk)~=bitsrc(kk)
errbits(nn)=errbits(nn)+1;
end;
end;
end;
errrate=errbits/len;
errrate0=0.5*exp(-snj2/2);
toc;
figure;
semilogy(snj,errrate0,'bo-',snj,errrate,'rd-');
legend('N=1的理论误比特率','实际仿真误比特率');
grid on;
