%equation_dfe-rls
close all
clear all
clc
signal_length=1000;                                                 
%信息序列的長度
training_sequence_length=25;
%訓練序列的長度
time=1;                                                    
%蒙特卡洛仿真的次數
K1=5;
%前饋濾波器的階數為K1+1
K2=5;
%后饋濾波器的階數為K2
N=K1+K2+1;
%均衡器的階數
channel=[0.26,
         0.93,
         0.26]; 
%針對p496頁的信道情況
path_number=length(channel);
%信道多徑的徑數
snr=15;
%信噪比
err_result=zeros(training_sequence_length,1); 
%求均方誤差
for k=1:time
    signal_in=randint(signal_length,1);  
    %產生信息序列
    signal_out_all=bpsk_mapping(signal_in);
    %進行QPSK映射
    signal_receive_all=channelpass(signal_out_all,channel,snr);
    %映射后的信號通過信道
    signal_out_training=[signal_out_all(1:1:training_sequence_length)];
    [signal_equation,signal_decision,filter_coefficient]=dferls_equation(K1,K2,signal_receive_all,signal_out_training);
    %先用訓練序列使濾波器的系數達到最佳值，然后傳輸信息
    signal_demapping=demapping(signal_decision);
    %進行QPSK解映射
    bit_error=xor(signal_demapping,signal_in([(training_sequence_length+1):(length(signal_in)+path_number-K1-2)],:));
    bit_error_rate=sum(bit_error)/length(bit_error);
    %計算誤碼率
end
%求均方誤差
scatterplot(signal_out_all),title('調制之后的星座圖')
%調制之后的星座圖
scatterplot(signal_receive_all) ,title('通過信道之后的星座圖')
%通過信道之后的星座圖
scatterplot(signal_equation) ,title('均衡之后的星座圖')
%均衡之后的星座圖