OFDM中LS和DFT信道估计算法matlab程序实现及比较

clear all;
close all;
fprintf（‘OFDM信道估计仿真\n\n‘）;
carrier_count=64;%-----------载波数目
num_symbol=50;%--------------OFDM符号个数
Guard=8;%--------------------循环前缀
pilot_Inter=8;%--------------导频间隔
modulation_mode=16;%---------调制方式
SNR=[0:2:20];%-------------信噪比取值
NumLoop=15;%-----------------循环次数
num_bit_err=zeros（length（SNR）NumLoop）;
num_bit_err_dft=zeros（length（SNR）NumLoop）;
num_bit_err_ls=zeros（length（SNR）NumLoop）;
MSE=zeros（length（SNR）NumLoop）;
MSE1=zeros（length（SNR）NumLoop）;
MSE2=zeros（length（SNR）NumLoop）;
%%%%%%%%%%%%%%%%%%%%%%%主程序循环%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for c1=1:length（SNR）
    fprintf（‘\n\n\n仿真信噪比为%f\n\n‘SNR（c1））;
    for num1=1:NumLoop
        %---------------产生发送的随机序列——————————————-
        BitsLen=carrier_count*num_symbol;
        BitsTx=randint（1BitsLen）;
        %---------------符号调制---------------------------------------
        Modulated_Sequence=qammod（BitsTxmodulation_mode）;
        %---------------导频格式---------------------------------------
        pilot_len=carrier_count;
        pilot_symbols=round（rand（1pilot_len））;
        for i=1:pilot_len
            if pilot_symbols（1i）==0
                pilot_symbols（1i）=pilot_symbols（1i）-1;
            else
                pilot_symbols（1i）=pilot_symbols（1i）;
            end
        end
        pilot_symbols=pilot_symbols‘;
        %----------------计算导频和数据数目----------------------------
        num_pilot=ceil（num_symbol/pilot_Inter）;
        if rem（num_symbolpilot_Inter）==0
            num_pilot=num_pilot+1;
        end
        num_data=num_symbol+num_pilot;
        %----------------导频位置计算----------------------------------
        pilot_Indx=zeros（1num_pilot）;
        Data_Indx=zeros（1num_pilot*（pilot_Inter+1））;
        for i=1:num_pilot-1
            pilot_Indx（1i）=（i-1）*（pilot_Inter+1）+1;
        end
        pilot_Indx（1num_pilot）=num_data;
        for j=0:num_pilot
            Data_Indx（1（1+j*pilot_Inter）:（j+1）*pilot_Inter）=（2+j*（pilot_Inter+1））:（（j+1）*（pilot_Inter+1））;
        end
        Data_Indx=Data_Indx（11:num_symbol）;
        %----------------导频插入-------------------------------------
        piloted_ofdm_syms=zeros（carrier_countnum_data）;
        piloted_ofdm_syms（:Data_Indx）=reshape（Modulated_Sequencecarrier_countnum_symbol）;
        piloted_ofdm_syms（:pilot_Indx）=repmat（pilot_symbols1num_pilot）;
        %----------------IFFT变换———————————————————
        time_signal=sqrt（carrier_count）*ifft（piloted_ofdm_syms）;
        %----------------加循环前缀------------------------------------
        add_cyclic_signal=[time_signal（（carrier_count-Guard+1:carrier_count）:）;time_signal];
        Tx_data_trans=reshape（add_cyclic_signal1（carrier_count+Guard）*num_data）;
        %----------------信道处理--------------------------------------
        Tx_signal_power=sum（abs（Tx_data_trans（:））.^2）/length（Tx_data_trans（:））;
        noise_var=Tx_signal_power/（10^（SNR（c1）/10））;