【误码率仿真】基于matlab 16QAM调制误码率对比（含误符号率 误比特率）【含Matlab源码 4529期】.zip

% 16QAM误符号率仿真 % 参考文献：数字通信（第四版 proakis）P202 clear all; close all; clc; %----------------------------------------------% % 参数设置 %----------------------------------------------% num= 1e6; Rb = 100; %比特速率，bps fs = Rb; Ts = 1/fs; Pm = zeros(1,29); Pm_symbol = zeros(1,29); Pm_bit = zeros(1,29); ser = zeros(1,29); ber = zeros(1,29); for Eb_N0 = 0:0.5:14 %dB，信噪比递增，便于作图 data_src = randint(1,num); a = data_src(1:4:num-3); b = data_src(2:4:num-2); c = data_src(3:4:num-1); d = data_src(4:4:num); I = zeros(1,num/4); Q = zeros(1,num/4); for index = 1:num/4%星座点映射 switch a(index)*2^3+b(index)*2^2+c(index)*2^1+d(index)*2^0 case 0 I(index) = 3; Q(index) = 3; case 1 I(index) = 1; Q(index) = 3; case 2 I(index) = 3; Q(index) = 1; case 3 I(index) = 1; Q(index) = 1; case 4 I(index) = -3; Q(index) = 3; case 5 I(index) = -1; Q(index) = 3; case 6 I(index) = -3; Q(index) = 1; case 7 I(index) = -1; Q(index) = 1; case 8 I(index) = 3; Q(index) = -3; case 9 I(index) = 1; Q(index) = -3; case 10 I(index) = 3; Q(index) = -1; case 11 I(index) = 1; Q(index) = -1; case 12 I(index) = -3; Q(index) = -3; case 13 I(index) = -1; Q(index) = -3; case 14 I(index) = -3; Q(index) = -1; case 15 I(index) = -1; Q(index) = -1; otherwise end end mapped_signal=I+1j.*Q; Es_N0 = Eb_N0 + 6.02;%16QAM Es_N0与Eb_N0转换 SNR = Es_N0; mapped_signal_awgn = awgn(mapped_signal,SNR,10); rec_I = real(mapped_signal_awgn); rec_Q = imag(mapped_signal_awgn); demod_I = zeros(1,num/4); demod_Q = zeros(1,num/4); demod_a = zeros(1,num/4); demod_b = zeros(1,num/4); demod_c = zeros(1,num/4); demod_d = zeros(1,num/4); for index = 1:num/4%硬判决 if rec_I(index)>=2 && rec_Q(index)>=2 demod_I(index) = 3; demod_Q(index) = 3; demod_a(index) = 0; demod_b(index) = 0; demod_c(index) = 0; demod_d(index) = 0; elseif rec_I(index)>=2 && rec_Q(index)<2 && rec_Q(index)>=0 demod_I(index) = 3; demod_Q(index) = 1; demod_a(index) = 0; demod_b(index) = 0; demod_c(index) = 1; demod_d(index) = 0; elseif rec_I(index)>=2 && rec_Q(index)<-2 demod_I(index) = 3; demod_Q(index) = -3; demod_a(index) = 1; demod_b(index) = 0; demod_c(index) = 0; demod_d(index) = 0; elseif rec_I(index)>=2 && rec_Q(index)<0 && rec_Q(index)>=-2 demod_I(index) = 3; demod_Q(index) = -1; demod_a(index) = 1; demod_b(index) = 0; demod_c(index) = 1; demod_d(index) = 0; elseif rec_I(index)>=0 && rec_I(index)< 2 && rec_Q(index)>=2 demod_I(index) = 1; demod_Q(index) = 3; demod_a(index) = 0; demod_b(index) = 0; demod_c(index) = 0; demod_d(index) = 1; elseif rec_I(index)>=0 && rec_I(index)< 2 && rec_Q(index)<2 && rec_Q(index)>=0 demod_I(index) = 1; demod_Q(index) = 1; demod_a(index) = 0; demod_b(index) = 0; demod_c(index) = 1; demod_d(index) = 1; elseif rec_I(index)>=0 && rec_I(index)< 2 && rec_Q(index)<-2 demod_I(index) = 1; demod_Q(index) = -3; demod_a(index) = 1; demod_b(index) = 0; demod_c(index) = 0; demod_d(index) = 1; elseif rec_I(index)>=0 && rec_I(index)< 2 && rec_Q(index)>=-2 && rec_Q(index)<0 demod_I(index) = 1; demod_Q(index) = -1; demod_a(index) = 1; demod_b(index) = 0; demod_c(index) = 1; demod_d(index) = 1; elseif rec_I(index)<-2 && rec_Q(index)>=2 demod_I(index) = -3; demod_Q(index) = 3; demod_a(index) = 0; demod_b(index) = 1; demod_c(index) = 0; demod_d(index) = 0; elseif rec_I(index)<-2 && rec_Q(index)<2 && rec_Q(index)>=0 demod_I(index) = -3; demod_Q(index) = 1; demod_a(index) = 0; demod_b(index) = 1; demod_c(index) = 1; demod_d(index) = 0; elseif rec_I(index)<-2 && rec_Q(index)<-2 demod_I(index) = -3; demod_Q(index) = -3; demod_a(index) = 1; demod_b(index) = 1; demod_c(index) = 0; demod_d(index) = 0; elseif rec_I(index)<-2 && rec_Q(index)<0 && rec_Q(index)>=-2 demod_I(index) = -3; demod_Q(index) = -1; demod_a(index) = 1; demod_b(index) = 1; demod_c(index) = 1; demod_d(index) = 0; elseif rec_I(index)>=-2 && rec_I(index)<0 && rec_Q(index)>=2 demod_I(index) = -1; demod_Q(index) = 3; demod_a(index) = 0; demod_b(index) = 1; demod_c(index) = 0; demod_d(index) = 1; elseif rec_I(index)>=-2 && rec_I(index)<0 && rec_Q(index)<2 && rec_Q(index)>=0 demod_I(index) = -1; demod_Q(index) = 1; demod_a(index) = 0; demod_b(index) = 1; demod_c(index) = 1; demod_d(index) = 1; elseif rec_I(index)>=-2 && rec_I(index)<0 && rec_Q(index)<-2 demod_I(index) = -1; demod_Q(index) = -3; demod_a(index) = 1; demod_b(index) = 1; demod_c(index) = 0; demod_d(index) = 1; elseif rec_I(index)>=-2 && rec_I(index)<0 && rec_Q(index)<0 && rec_Q(index)>=-2 demod_I(index) = -1; demod_Q(index) = -1; demod_a(index) = 1; demod_b(index) = 1; demod_c(index) = 1; demod_d(index) = 1; end end data_rec(1:4:num-3) = demod_a; data_rec(2:4:num-2) = demod_b; data_rec(3:4:num-1) = demod_c; data_rec(4:4:num) = demod_d; %------------------计算理论值----------------% M = 16; Eb_N0_actual = 10^(Eb_N0/10); a = sqrt(3*log2(M)*Eb_N0_actual/(2*(M-1))) ; Q = 0.5*erfc(a); Pm(Eb_N0*2+1) = 2*(1-1/sqrt(M))*Q; Pm_symbol(Eb_N0*2+1) = 1 - (1-Pm(Eb_N0*2+1))^2;%计算理论误符号率 Pm_bit(Eb_N0*2+1) = Pm_symbol(Eb_N0*2+1)/4;%理论误码率公式未找到，近似计算理论误比特率，高信噪比下较准，低信噪比下比真值小 %------------------计算实际误符号率----------------% demod_signal = demod_I+1j*demod_Q; cnt = 0; for index = 1:num/4 if mapped_signal(index) ~= demod_signal(index) cnt = cnt + 1; end end ser(Eb_N0*2+1) = cnt/(num/4);%得到实际误符号率 %------------------计算实际误比特率----------------% cnt1 = 0; for index = 1:num if data_rec(index) ~= data_src(index) cnt1 = cnt1 + 1; end end ber(Eb_N0*2+1) = cnt1/num;%得到实际误符号率 end figure; semilogy((0:0.5:14),ser,'-*b');grid on; hold on; semilogy((0:0.5:14),Pm_symbol,'-+r');grid on;%作图比较 title('误符号率'); figure; semilogy((0:0.5:14),ber,'-*b');grid on; hold on; semilogy((0:0.5:14),Pm_bit,'-+r');grid on;%作图比较 title('误比特率');