IPOINT = 4; % 码片速率过采样倍数（4倍
alfs = 0.22; % 滚降因子
[xh] = hrollfcoef(irfn,IPOINT,sr,alfs,1); %发送端根升余弦滤波器系数 %%hrollfcoef指
[xh2] = hrollfcoef(irfn,IPOINT,sr,alfs,0); %接收端根升余弦滤波器系数
%++++++++++++++++++++++++扩频码初值设定+++++++++++++++++++ user = 4; % 用户数
%seq = 2; % 1:m序列 2:Gold序列 3:正交Gold序列 stage = 5; % 序列阶数
ptap1 = [2 5]; % 第一个线性移位寄存器的系数 ptap2 = [1 2 3 5]; % 第二个线性移位寄存器的系数 regi1 = [1 1 1 1 1]; % 第一个线性移位寄存器的初始化 regi2 = [1 1 1 1 1]; % 第二个线性移位寄存器的初始化 %移位寄存器级数 3，码长 7.
% 5 31
%+++++++++++++++++扩频码的产生+++++++++++++++++ m1 = mseq(stage,ptap1,regi1); m2 = mseq(stage,ptap2,regi2);
code = [goldseq(m1,m2,user),zeros(user,1)]; %正交 Gold序列 code = code * 2 - 1; %双极性 clen = length(code);
data = rand(user,nd) > 0.5; dlen = length(data);
data_m = data.*2 -1; %QPSK; data_s=zeros(user,dlen*(2^stage));
for i1=1:1:user %扩频 data_s(i1,:)=kron(data_m(i1,:),code(i1,:));
end
data_os = compoversamp2(data_s,IPOINT); % 过采样 data_f1 = compconv2(data_os,xh); % 滤波
if user == 1
data_f = data_f1; else
data_f = sum(data_f1); end
disp('--------------Send Data ...-------------------'); loo=0;
for kk=1:1:length(SNR)
data_n=awgn(data_f,SNR(kk),'measured');%在信号data_f中加入高斯白噪声
data_rf = compconv2(data_n,xh2); % 滤波
sampl = irfn * IPOINT + 1;
data_ros = data_rf(:,sampl:IPOINT:IPOINT*nd*clen+sampl-1); %减采样
%++++++++++解扩++++++++ data_rs=zeros(user,dlen); scused=ones(1,dlen);
for i2=1:1:user
bds=kron(scused,code(i2,:)); %将Gold码矩阵的i2行，复制scused次 ds=bds.*data_ros(1,:); %反哈达玛变换（解扩）
rds=reshape(ds,clen,length(data_ros(1,:))/clen);%对ds重新排列成 hl行，length(s)/hl。
%注：(reshape数据排列顺序：从上往下，从左往右)
ou=sum(rds); %对每列求和 t=length(ou);
en=zeros(1,t); for a=1:t
if ou(a)>1 %抽样判决 en(a)=1; else
en(a)=-1; end end
data_rs(i2,:)=en; end
%++++++++++++++++++
data_rm=(data_rs+1)./2;%BPSK解调 loo=loo+1;
[n(loo),r(loo)]=symerr(data_m,data_rs); %[number,ratio] = symerr(x,y) end
disp('----------------Calculate Finished-------------------'); disp('----------------Start Plot-------------------'); %根升余弦滤波器
figure('Name','根升余弦滤波器','NumberTitle','on'); % Tx
subplot(211);stem(xh);grid; xlabel('Bits index');
title('发送端根升余弦滤波器'); % Rx
subplot(212);stem(xh2);grid; xlabel('Bits index');
title('接收端根升余弦滤波器'); %误码率-信噪比关系图
figure; % plot the BER vs. SNR semilogy(SNR,r,'r-x'),grid; xlabel('SNR');ylabel('BER'); title('BER vs. SNR');
%原始数据，发送和接收的比较
figure('Name','Original Data','NumberTitle','on');
% plot data for a randomly selected user such as user no. 1 before the BPSK mapping Tx and Rx
% Tx
subplot(211);stem(data(cuser,1:20),'filled');grid; xlabel('Bits index');
title('Transmitted Bits (showing only 20 bits)'); % Rx
subplot(212);stem(data_rm(cuser,1:20),'filled');grid; xlabel('Bits index');
title('Received Bits (showing only 20 bits)');
%BPSK编码后，发送和接收的比较
figure('Name','BPSK Symbols','NumberTitle','on');
% plot data for a randomly selected user such as user no. 1 after the BPSK mapping Tx and Rx
% Tx
subplot(211);stem(data_m(cuser,1:20),'filled');grid; xlabel('Symbol index');
title('Transmitted BPSK Symbols (showing only 20 Symbol)'); % Rx
subplot(212);stem(data_rs(cuser,1:20),'filled');grid;
xlabel('Symbol index');
title('Received BPSK Symbols (showing only 20 Symbol)');
%要发送的数据，各个用户对应位求和的结果
figure('Name','Combined signals','NumberTitle','on');%plot combined signals %Tx
subplot(211);stem(data_f(1:50),'filled'); title('Combined signals (only 20 symbols)'); xlabel('Index of Combined symbols'); ylabel('Magnitude'); grid;
%Rx
subplot(212);stem(data_ros(1:50),'filled'); title('Combined noisy signals (only 20 symbols）'); xlabel('Index of Combined symbols');
ylabel('Magnitude'); grid;
disp('----------------Plot Finished-------------------');