16QAM-星形和矩形星座图调制解调MATLAB代码

16QAM-星形和矩形星座图调制解调MATLAB代码

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------------------------------------------------------------ % 软件无线电课程设计

%

% 方形、星形16QAM调制解调仿真%

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%%主程序

clc

clear

%% 定义参数

fd=250*10^6; %码元速率250M

fs=2500*10^6; %滤波器采样率

fc=2500*10^6; %载波频率2.5G

f=10000*10^6; %对载波采样

data_len=200000; %数据长度

sym_len=data_len/4; %码元序列长度

M_QAM=16;%QAM数

k=log2(M_QAM);

SNR=1:12;%白噪声信噪比,

%%

------------------------------------------------------------ bit_tx=randint(1,data_len);%产生随机序列echo off;

rec_qam16=QamMod(bit_tx,16);

%方形16QAM调制

star_qam16=SrarQamMod(bit_tx);

%星形16QAM调制

base_rec=base_shape(fd,fs,f,rec_qam16);

%基带成型滤波

base_star=base_shape(fd,fs,f,star_qam16); %基带成型滤波

for

i=1:length(SNR) %信噪比从1dB到12dB计算误码率

SNR_=i

%方形映射16QAM

rf_rec_qam16=CarrierMod(fc,f,base_rec);

%载波调制

rf_rec_qam16_n=awgn(rf_rec_qam16,SNR(i),'m easured'); %加噪声

[rec_qam16_rx

base_rec_rx]=CarrierDemod(fd,fs,fc,f,rf_rec_qa m16_n); %载波解调

bit_rec_rx=QamDemod(rec_qam16_rx,16);

%MQAM解调

[num_qam16,perr_qam16_rec(i)]=biterr(bit_tx, bit_rec_rx);%误码率

qam16_data_rec(i,:)=rec_qam16_rx;

%scatterplot(rec_qam16_rx);

%星形映射16QAM

rf_star_qam16=CarrierMod(fc,f,base_star);

%载波调制

rf_star_qam16_n=awgn(rf_star_qam16,SNR(i),' measured'); %加噪声

[star_qam16_rx

base_star_rx]=CarrierDemod(fd,fs,fc,f,rf_star_ qam16_n); %载波解调

bit_star_rx=StarQamDemod(star_qam16_rx);

%MQAM解调

[num_qam16,perr_qam16_star(i)]=biterr(bit_tx ,bit_star_rx);%误码率

qam16_data_star(i,:)=star_qam16_rx;

%scatterplot(star_qam16_rx);

end

%% 理论误码率计算

SNRtheo=0:0.1:length(SNR);

for i=1:length(SNRtheo)

SNRdec=10.^(SNRtheo(i)/10);

theo_perr_qam16(i)=(3/8)*erfc(sqrt(SNRdec*2/ 5));

end

%% 基带波形

N=200;

n=1:N;

t=1:N*10;

%发送端波形

figure;

stem(n,bit_tx(n)); title('发送序列'); %发送序列

figure('Name','发送端基带信号');

subplot(411);

plot(t,real(base_rec(t))); title('方形映射-Q路');

subplot(412);

plot(t,imag(base_rec(t))); title('方形映射-I路');

subplot(413);

plot(t,real(base_star(t))); title('星形映射-Q路

subplot(414);

plot(t,imag(base_star(t))); title('星形映射-I路');

%接收端波形

figure;

subplot(211);

stem(n,bit_rec_rx(n)); title('方形接收序列');

subplot(212);

stem(n,bit_star_rx(n)); title('星形接收序列');

figure('Name','接收端基带信号');

subplot(411);

plot(t,real(base_rec_rx(t))); title('方形映射-Q 路');

subplot(412);

plot(t,imag(base_rec_rx(t))); title('方形映射-I 路');

subplot(413);

plot(t,real(base_star_rx(t))); title('星形映射-Q路');