【信道容量】 QPSK+8PSK+16PSK+16QAM数字信号调制信道容量仿真【含Matlab源码 2784期】.zip

clc clear all snr=-10:1:35; %snr是信噪比 PsPn=10.^(0.1*snr); %Ps/Pn是信号功率比噪声功率，也是信号和噪声的能量比 Capacity=[]; %信道容量 log2py=[]; %信道容量公式第一项 signal_space=[]; %信号空间 sample=66666; %样本个数 %QPSK 8PSK 16PSK调制的信道容量曲线 for k=2:4 M=2.^k; if k==2 %QPSK信号星座图 signal_space(1) = complex(1,1); signal_space(2) = complex(-1,1); signal_space(3) = complex(-1,-1); signal_space(4) = complex(1,-1); end if k==3 %8PSK信号星座图 signal_space(1) = complex(1,0); signal_space(2) = complex(cos(pi/4),sin(pi/4)); signal_space(3) = complex(0,1); signal_space(4) = complex(cos(3*pi/4),sin(3*pi/4)); signal_space(5) = complex(-1,0); signal_space(6) = complex(cos(5*pi/4),sin(5*pi/4)); signal_space(7) = complex(0,-1); signal_space(8) = complex(cos(-pi/4),sin(-pi/4)); end if k==4 %16PSK信号星座图 signal_space(1) = complex(1,0); signal_space(2) = complex(cos(pi/8),sin(pi/8)); signal_space(3) = complex(cos(pi/4),sin(pi/4)); signal_space(4) = complex(cos(3*pi/8),sin(3*pi/8)); signal_space(5) = complex(0,1); signal_space(6) = complex(cos(5*pi/8),sin(5*pi/8)); signal_space(7) = complex(cos(3*pi/4),sin(3*pi/4)); signal_space(8) = complex(cos(7*pi/8),sin(7*pi/8)); signal_space(9) = complex(-1,0); signal_space(10) = complex(cos(7*pi/8),sin(-7*pi/8)); signal_space(11) = complex(cos(3*pi/4),sin(-3*pi/4)); signal_space(12) = complex(cos(5*pi/8),sin(-5*pi/8)); signal_space(13) = complex(0,-1); signal_space(14) = complex(cos(3*pi/8),sin(-3*pi/8)); signal_space(15) = complex(cos(pi/4),sin(-pi/4)); signal_space(16) = complex(cos(pi/8),sin(-pi/8)); end Es=sum((abs(signal_space)).^2)/M; %调制信号能量Es for i=1:1:length(snr) No=Es/PsPn(i); %能量比等于功率比 for j=1:1:sample x(j)=signal_space(floor(rand*M)+1); %输入随机信号 end y=x+sqrt(No./2)*complex(randn(1,sample),randn(1,sample)); %信号叠加噪声 for j=1:1:sample pysm=0; for b=1:1:M pysm=pysm+exp(-(abs(y(j)-signal_space(b))).^2/No); end log2py(j)=log2(1/M/(pi*No)*pysm); %信道容量公式第一项的和 end Capacity(i)=-mean(log2py)-log2(pi*exp(1)*No); %mean函数可以直接得出矩阵的均值 end EbNo=10*log10(PsPn./Capacity); if k==2 plot(EbNo,Capacity,'b--'); %QPSK调制信道容量曲线 end hold on; if k==3 plot(EbNo,Capacity,'r-.'); %8PSK调制信道容量曲线 end hold on; if k==4 plot(EbNo,Capacity,'k:'); %16PSK调制信道容量曲线 end hold on; end %16QAM调制的信道容量曲线 k=4; M=2.^k; signal_space(1) = complex(1,1); signal_space(2) = complex(1,3); signal_space(3) = complex(3,1); signal_space(4) = complex(3,3); signal_space(5) = complex(-1,1); signal_space(6) = complex(-1,3); signal_space(7) = complex(-3,1); signal_space(8) = complex(-3,3); signal_space(9) = complex(-1,-1); signal_space(10) = complex(-1,-3); signal_space(11) = complex(-3,-1); signal_space(12) = complex(-3,-3); signal_space(13) = complex(1,-1); signal_space(14) = complex(1,-3); signal_space(15) = complex(3,-1); signal_space(16) = complex(3,-3); Es=sum((abs(signal_space)).^2)/M; %调制信号能量Es for i=1:1:length(snr) No=Es/PsPn(i); %能量比等于功率比 for j=1:1:sample x(j)=signal_space(floor(rand*M)+1); %输入随机信号 end y=x+sqrt(No./2)*complex(randn(1,sample),randn(1,sample)); %信号叠加噪声 for j=1:1:sample pysm=0; for b=1:1:M pysm=pysm+exp(-(abs(y(j)-signal_space(b))).^2/No); end log2py(j)=log2(1/M/(pi*No)*pysm); %信道容量公式第一项的和 end Capacity(i)=-mean(log2py)-log2(pi*exp(1)*No); %mean函数可以直接得出矩阵的值 end EbNo=10*log10(PsPn./Capacity); plot(EbNo,Capacity,'c-'); xlabel('Eb/No(dB)'); ylabel('Capacity(比特每信道容量)'); axis([-2,20,0,5]); grid on; text(18,2.2,'QPSK') ; text(18,3.2,'8PSK') ; text(18,3.8,'16PSK' ) ; text(18,4.2,'16QAM') ;