matlab仿真OFDM
%%%%%%%%%%%Developed for 16 QAM %%%%%%%%%%%%%%clear all
close all
t0=clock;
%%%%%%%INPUT PARAMETERS %%%%%%%%%%%
%%%%%N=, Number of FFT Points
N=1024;
%%%%% M=, Number of OFDM Sub Carriers
M=512;
%%%%% L=, Number of Symbols
L=10;
MMMa=16;%%%% Modulation Method %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% QPSK 16QAM
MMM1a=log2(MMMa);
%%%%% Tg=, Gurd Interval Ratio %%%%%%%%
Tg=0.1;
W=10;%%% Bandwidth(MHz)
DFF=W/M;
%%%%%% ts=, Effective Sumbol Duration (Micro Sec) %%%%%%%
ts=M/W;
%%%%%% D=, Gurd Interval Duration (Micro Sec) %%%%%%%
D=ts*Tg;
%%%%%% Ts=, Symbol Duration (Micro Sec) %%%%%%%%%%
Ts=ts+D;
st1=ts/N;
%%%%%%% Ng=, Number of Samples for Gurd Interval %%%%%%%
Ng=round(D/(ts/N));
%%%%%%% Nt=, Number of Samples for a Symbol %%%%%%%
Nt=(N+Ng);
%%%%%%% NNt=, Number of Samples for a Flame %%%%%%
NNt=Nt*L;
%%%%%%%%% Sampling frequency (usec) %%%%%%%%%%
tbw=1/st1;
%%%%%%% tsw=, Total Allocated Signal Bandwidth (MHz) %%%%%%%
tsw=(1/ts*M);%%%% W bandwidth
ddf=tbw/NNt; %%%% Frequency resolution
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
dt=0.1;%%%%%%delay spread
ds=st1;%%%%%%delay spacing
NP=10;%%%%%% number of delay path
%%% Power Delay profile withExponential decay constant
amp(1)=0.7854;
amp(2)=0.4861;
amp(3)=0.3009;
amp(4)=0.1863;
amp(5)=0.1153;
amp(6)=0.0714;
amp(7)=0.0442;
amp(8)=0.0273;
amp(9)=0.0169;
amp(10)=0.0105;
dts1(1:NP)=0:9;
%=f_MUL(NP,dt,ds,st1);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
cn=30;%%% dB
cn1=10^(-cn/10);
LLL=1;%%% Number of trial
for KLL=1:LLL;
if mod(KLL,1)==0,KLL
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
zxn1=zeros(1,NP);
zyn1=zeros(1,NP);
zn1=zeros(1,NP);
zn2=zeros(1,NP);
phn=zeros(1,NP);
amp1=zeros(1,NP);
qd3=zeros(1,NNt);
%%% Generation of Rayleigh fading
%%% Amplitude
zxn1(1:NP)=randn(1,NP);
zyn1(1:NP)=randn(1,NP);
zn1(1:NP)=zxn1(1:NP)+j*zyn1(1:NP);
zn2(1:NP)=abs(zn1(1:NP))/sqrt(2);
%%% Phase
phn(1:NP)=atan2(zyn1(1:NP),zxn1(1:NP));
amp1(1:NP)=zn2(1:NP).*amp(1:NP).*exp(j*phn(1:NP));
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
ya=zeros(L,M);
x3=zeros(L,N);
L1=N/2+1-M/2;
L2=N/2+M/2;
%%%%%%%%%%%%%Data generation %%%%%%%%%%%%%%
ya(1:L,1:M)=randint(L,M,MMMa);
%%%%%%%%%%%%% Modulation %%%%%%%%%
x3(1:L,L1:L2)=f_EnMQAM(ya(1:L,1:M),MMMa);
%%%%%%%%%%%Converting from Frequency to Time domain signal %%%%%%%%%
for k=1:L;
zz1(k,1:N)=ifft(fftshift(x3(k,1:N)))*sqrt(N);
%%%% Adding Guard Interval
z3(k,1:Nt)=;
end
q13=z3';
q73=q13(:)';
%%%%%%%%%% Evaluation of Power Spectrum under AWGN condition
q73a=fftshift(fft(q73));
pow1=q73a.*conj(q73a);
pow2=10*log10(pow1/max(pow1));
%%%%%%%%%%%
po3=mean(q73.*conj(q73));
c3=po3/2*cn1;
%%%%%% Noise Generation %%%%%
zxc(1:L,1:Nt)=sqrt(c3).*randn(L,Nt);
zyc(1:L,1:Nt)=sqrt(c3).*randn(L,Nt);
znc(1:L,1:Nt)=zxc(1:L,1:Nt)+j*zyc(1:L,1:Nt);
znn1c=znc';
znnc=znn1c(:)';
qd3(1:NNt)=amp1(1).*q73(1:NNt);
%%%% Generation of Multi-path fading signal
for k=2:NP;
qu23(k,1:NNt)=;
qu23(k,1:NNt)=amp1(k).*qu23(k,1:NNt);
qd3(1:NNt)=qd3(1:NNt)+qu23(k,1:NNt);
end
%%%%%%%%%% Evaluation of Power Spectrum under multi-path fading condition
qd3a=fftshift(fft(qd3));
pow3=qd3a.*conj(qd3a);
pow4=10*log10(pow3/max(pow3));
%%%% Adding AWGN
q73x=qd3+znnc;
q73y=q73+znnc;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
imax=1;
%%% Removing Guard interval
for k=1:L;
p93(k,1:Nt)=q73x(imax-1+(k-1)*Nt+(1:Nt));
p993(k,1:N)=;
%%%%%%%%%%FFT %%%%%
p813(k,1:N)=fftshift(fft(p993(k,1:N))/sqrt(N));
HH3(1:M)=p813(1,L1:L2)./x3(1,L1:L2);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
p8x3(k,1:M)=p813(k,L1:L2)./HH3(1:M);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
p93y(k,1:Nt)=q73y(imax-1+(k-1)*Nt+(1:Nt));
p993y(k,1:N)=;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%
p813y(k,1:N)=fftshift(fft(p993y(k,1:N))/sqrt(N));
p8y3(k,1:M)=p813y(k,L1:L2);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
end
%%% Demodulation of signal under AWGN
pb1(1:L,1:M)=f_DeMQAM(p8x3(1:L,1:M),MMMa);%%%
%%% evaluation of bit error rate performance
per1(KLL)=biterr(pb1(2:L,1:M),ya(2:L,1:M))/(M*(L-1)*MMM1a);
%%% Demodulation of signal under multi-path fading
pb2(1:L,1:M)=f_DeMQAM(p8y3(1:L,1:M),MMMa);%%%
per2(KLL)=biterr(pb2(2:L,1:M),ya(2:L,1:M))/(M*(L-1)*MMM1a);
end
%%%% Final BER
ERR1=mean(per1(1:LLL));
ERR2=mean(per2(1:LLL));
%%%%%%%%%%%%%%%%%%%%%%%%
figure(1)%%%%%% Information Real Data in Freq
stem(real(x3(2,1:N)))
grid on
figure(2)%%%%%% Information Imag Data in Freq
stem(imag(x3(2,1:N)))
grid on
figure(3)%%%%%% Time domain signal
plot(abs(z3(1,1:Nt)))
grid on
figure(4)
plot(abs(z3(1,1:Ng)))
grid on
figure(5)
plot(abs(z3(1,Nt-Ng:Nt)))
grid on
figure(6)
plot(pow2)
grid on
figure(7)
plot(pow4)
grid on
figure(8)
plot(abs(HH3))
grid on
figure(9)
stem(real(p8x3(2,1:M)))
grid on
figure(10)
stem(imag(p8x3(2,1:M)))
grid on
figure(11)
plot(p8x3(2:L,1:M),'x')
grid on
figure(12)
plot(p8y3(2:L,1:M),'x')
grid on
etime(clock,t0)/60
:)
正在学习这个,真是太感谢了:) randint 是什么意思？回复 #3 zhouwh 的帖子
help randint～～
有错误啊。f_EnMQAM这是啥东西呢？ thank you very much 是啊，有错误啊，
??? Undefined function or variable 'f_EnMQAM'.
Error in ==> E:\MATLAB6p5\work\Untitled333.m
On line 87==> x3(1:L,L1:L2)=f_EnMQAM(ya(1:L,1:M),MMMa);
谁能给解释下啊
怎么改？
刚开始学，不大懂
回复 7楼 haobaobao521 的帖子
太长了, 懒, 没细看可能是自订函数吧, 楼主可能为给齐
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