认知无线电频谱感知之功率检测matlab代码

能量检测仿真实验代码：

clear all;clc; n = 5; ps = 1; SNR1 = -5; SNR2 = -8; SNR3 = -10;

% Sim_Times=10000; %Monter-Carlo times % m=5; T=0.001;

% 信号带宽W W=5*10^4; % 采样频率 Fs = 2*W; m = T*W; n = 2*T*W; % F0=W; % Fs=2;

% Sig=sqrt(2)*sin(2*pi*F0/Fs*t); %single tone samples, Fs=2F0 % 实际信噪比

snr1 = 10.^(SNR1/10); snr2 = 10.^(SNR2/10); snr3 = 10.^(SNR3/10); pn = (1/snr1)*ps; mu0 = n*pn;

sigma0 = sqrt(2*n)*pn; mu = n*(pn+ps);

sigma = sqrt(2*n*(pn^2+2*pn*ps));

% [noi,x0,mu0,sigma0,m0] = cnoi( n,pn ); % sig = randn(n,1); sig = 1; % 重复次数 count = 5000;

% 能量检测判决门限 lambda = [200:20:600]; lambda1 = [500:20:900]; lambda2 = [700:30:1300]; % 置信度判决参数 % tt = [-5:0.4:3]; % cc = 10.^tt;

% tt1 = [-1:0.1:1]; % cc1 = 10.^tt;

% cc2 = [-0.01:0.001:0.01];

for kk = 1:1:length(lambda); ff = 0; dd = 0; ff1 = 0; dd1 = 0; ff2 = 0; dd2 = 0;

for ii=1:1:count; t = (kk-1)*n+1:kk*n; init_phase = 1/6*pi;

sig=2*sin(2*pi*W/Fs*t+init_phase); %sig=1;

%dot(sig,sig)/n noi1 = randn(1,n);

noi1 = sqrt(1/snr1)*noi1; rec1 = noi1 + sig; noi2 = randn(1,n);

noi2 = sqrt(1/snr2)*noi2; rec2 = noi2 + sig; noi3 = randn(1,n);

noi3 = sqrt(1/snr3)*noi3; rec3 = noi3 + sig;

sum0_1 = dot(noi1,noi1); sum0_2 = dot(noi2,noi2); sum0_3 = dot(noi3,noi3); sum1_1 = dot(rec1,rec1); sum1_2 = dot(rec2,rec2); sum1_3 = dot(rec3,rec3); %单用户能量检测判决

if (sum0_1 > lambda(kk)); ff = ff+1; end

if (sum1_1 > lambda(kk)); dd = dd+1; end

if (sum0_2 > lambda1(kk)); ff1 = ff1+1; end

if (sum1_2 > lambda1(kk)); dd1 = dd1+1; end

if (sum0_3 > lambda2(kk)); ff2 = ff2+1; end

if (sum1_3 > lambda2(kk)); dd2 = dd2+1; end end

Pd_1(kk) = dd/count; Pf_1(kk) = ff/count; Pd_2(kk) = dd1/count; Pf_2(kk) = ff1/count; Pd_3(kk) = dd2/count; Pf_3(kk) = ff2/count; end

plot(Pf_1,Pd_1,'-o',Pf_2,Pd_2,'-s',Pf_3,Pd_3,'-*'); hold on; grid on;

xlabel('False alarm probability, P_{Fa}'); ylabel('Detection probability, P_{d}');

legend('能量检测 SNR=-5dB,n=100','能量检测 SNR=-8dB,n=100','能量检测 SNR=-10dB,n=100'); grid on; hold on;

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