%  表示t2*r4系統,碼率= 1;
% 16qam 64qam   %qam調制有2種情況(4=16qam,6=64qam);
% Max_quantity_bits 輸入輸出量化比特位數
% Ofdm_bits 一個Ofdm符號的比特個數
% Time_length 假設在這個時間間隔中信道特性不發生變化
%------------需要自定義的參數-------------------------------------------%
% snr_min 迭代的最小的信噪比
% snr_max 迭代的最大的信噪比
% stepsize 迭代的步長

clear
clc

global table16 table64 Mod_type Ofdm_bits Time_length Tx_num Rx_num
global Max_quantity_bits Max_value Min_value Max_add_value
snr_min=0;
snr_max=30;
stepsize = 2.5;
Mod_type = 4;           
Ofdm_bits = 10000;        %一個ofdm符號長度
%-------------全局參量--------------------------------%
Tx_num = 2;             
Rx_num = 2;             
Time_length = 2;       
pqam_length = Ofdm_bits*Mod_type;          
%----------------量化參量-----------------------------%
Max_quantity_bits = 8;
Max_value = 2^(Max_quantity_bits-1);
Min_value = -Max_value;
Max_add_value = 2^(2*Max_quantity_bits-1);
%---------------------------------qam 映射--------------------------------------------------------%
sig_code = randint(Tx_num,pqam_length);
stbc_code = qam_mod(sig_code);

%-------------------函數stbc_decode完成stbc的譯碼（定點）-----------------------------------------%
table16 = table16*Max_value;
table64 = table64*Max_value;
table64 = fix(table64*127/138);
iterative_length = 0;
demap_out = zeros(Tx_num,pqam_length);
for snr_db_step =snr_min:stepsize:snr_max  
    iterative_length = iterative_length+1
    [rec_code,ch_mul_noice] = mimo_channel(stbc_code,snr_db_step);
    [decode_out,demap_int] = stbc_decode22(rec_code,ch_mul_noice,snr_db_step);
    demap_out = qam_demod(demap_int);
    error_ratio = err_static(demap_out,sig_code);
    e_record(iterative_length) = error_ratio;
end % snr_db_step =snr_min:snr_max 
%_________________________________________繪圖__________________________________________________%

xanxis = snr_min:stepsize:snr_max;  
if Mod_type == 4
    semilogy(xanxis,e_record,'mo-');  
elseif Mod_type == 6
    semilogy(xanxis,e_record,'k*-'); 
end
grid on;
hold on;
title('T2R2 系統');