多径瑞丽信道调制BPSK、QPSK、16QAM、64QAM

number_ofdm_signal=50; %Number of ofdm symbol for one loop 250 SNR_dB=[0 5 10 15 20 25 30]; % SNR per bit, i.e. Eb/N0, in dB % SNR_dB=30; ls_err_ber_64QAM=zeros(1,length(SNR_dB)); lmmse_err_ber=zeros(1,length(SNR_dB)); lr_lmmse_err_ber=zeros(1,length(SNR_dB)); DFT_err_ber=zeros(1,length(SNR_dB)); lmmse_mse=zeros(1,length(SNR_dB)); ls_mse=zeros(1,length(SNR_dB)); DFT_mse=zeros(1,length(SNR_dB)); % 2. MODULATION MODE BPSK = 1; %modulation type is bpsk QPSK = 2; %modulation type is qpsk QAM16 = 3; %modulation type is 16qam QAM64=4; mod_type = QAM64; % mod_type = QAM16; % mod_type = QPSK; % mod_type = BPSK; % 4. PILOT MODE BLOCK=1; COMB=2; pilot_type=BLOCK; pilot_insert_flag=0; %pilot_type=COMB; nloop=3; %Number of simulation loops % --------------------------------------------- % B: % +++++ TRANSMITTER +++++ % --------------------------------------------- for i=1:length(SNR_dB) %每个SNR点上仿真若干次 ls_error_bit=0; lmmse_error_bit=0; DFT_error_bit=0; total_bit_num=0; for iii=1:nloop % 1. chose the modulation type [serildata,para,fftlen]=bitcreate(mod_type,number_ofdm_signal); % dSource=modulation(serildata,64); [dSource,pilot_symbol_bit,symbol_bit] = baseMapping(serildata,mod_type); %按照不同的方式进行调制 dSource1=reshape(dSource,12800,2);%mod_type=16qam % dSource1=reshape(dSource,3200,2);%mod_type=qpsk a=dSource1(:,1); b=dSource1(:,2); figure(1); plot(dSource1,'*r');%绘制16QAM星座图 axis([-8 8 -8 8]); title('64QAM调制后星座图'); ylabel('Q'); xlabel('I'); % title('QPSK调制后星座图'); % title('16QAM调制后星座图'); grid on % 2. convert serial data to parall data 串并转换 paradata1=reshape(a,fftlen,number_ofdm_signal); paradata2=reshape(b,fftlen,number_ofdm_signal); % 3. insert pilot 插入导频 % c=hadamard(1024);%16QAM % c=hadamard(128);%QPSK c=randsrc(1536,2,[0,1;0.5,0.5]);%64QAM pilot_symbol_bit1=c(:,1); pilot_symbol_bit2=c(:,2);%插入的已知导频 [insert_pilot_out1,pilot_num,pilot_sequence1,pilot_space]=insert_pilot(pilot_symbol_bit1,paradata1,pilot_type,mod_type); [insert_pilot_out2,pilot_num,pilot_sequence2,pilot_space]=insert_pilot(pilot_symbol_bit2,paradata2,pilot_type,mod_type); % 4. IFFT transform ifft_out11=ifft(insert_pilot_out1); ifft_out22=ifft(insert_pilot_out2); % Nomalize the powerp; ifft_out1=ifft_out11.*sqrt(fftlen); ifft_out2=ifft_out22.*sqrt(fftlen); % 5. Guard intervals were inserted to eliminate ISI caused by multipath fading 插入保护间隔以消除符号间干扰 guard_internal= (fftlen*1/8); %Length of guard internal ofdm_guard_interval_out1=guard_interval_insert(ifft_out1,fftlen,guard_internal); ofdm_guard_interval_out2=guard_interval_insert(ifft_out2,fftlen,guard_internal); % 6. convert paradata into seridata 并串转换 ofdm_guard_interval_out_serial1=reshape(ofdm_guard_interval_out1,1,(fftlen+guard_internal)*(number_ofdm_signal+pilot_num)); ofdm_guard_interval_out_serial2=reshape(ofdm_guard_interval_out2,1,(fftlen+guard_internal)*(number_ofdm_signal+pilot_num)); % --------------------------------------------- % C: % +++++ CHANNEL +++++ % --------------------------------------------- % 1. multipath Rayleigh fading and doppler spread channel %假设功率延迟谱服从负指数分布~exp(-t/trms),trms=(1/4)*cp时长； %t在0~cp时长上均匀分布 %若cp时长为16e-6s，可以取5径延迟如下 multipath_number=6; delay=[0 0.2e-6 0.5e-6 1.6e-6 2.3e-6 5e-6]; %delay=[0 2e-6 4e-6 8e-6 12e-6]; % delay=[0 0.77e-6 1.92e-6 6.14e-6 8.83e-6 19.2e-6]; %trms=4e-6; %trms为多径平均延迟 trms=8e-6; %trms为多径平均延迟 var_pow=10*log10(exp(-delay/trms)); %var_pow是各条多径的功率系数 % doppler_frequency=20; doppler_frequency=5;%最大doppler频率为5Hz t_interval=1e-6;%采样间隔为1us counter=300000;%各径信道的采样点间隔，应该大于信道采样点数。由以上条件现在信道采样点数 count_begin=(iii-1)*(20*counter);%每次仿真信道采样的开始位置 trms_1=trms/t_interval; t_max=32e-6/t_interval; %信道采样点数，每个调制符号采一个点 passchan_ofdm_symbol1=multipath_chann(ofdm_guard_interval_out_serial1,multipath_number,var_pow,delay,doppler_frequency,t_interval,counter,count_begin); passchan_ofdm_symbol2=multipath_chann(ofdm_guard_interval_out_serial2,multipath_number,var_pow,delay,doppler_frequency,t_interval,counter,count_begin); % % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % %Contaminating the transmitted data with AWGN % % spow=sum(ich3.^qch3)./number_ofdm_signal./para; % % attn=0.5*spow*sr/br*10.^(-EbN0/10); % % attn=sqrt(attn) + eps; % % [ich4,qch4]=comb(ich3,qch3,attn); % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 2. add AWGN to multipath-signal snr=10^(SNR_dB(i)/10); % code_power1=norm(ofdm_guard_interval_out_serial1)^2/(length(ofdm_guard_interval_out_serial1)); %信号的符号功率 =var(passchan_ofdm_symbol) % code_power2=norm(ofdm_guard_interval_out_serial2)^2/(length(ofdm_guard_interval_out_serial2)); code_power1=norm(passchan_ofdm_symbol1)^2/(length(passchan_ofdm_symbol1)); %信号的符号功率 =var(passchan_ofdm_symbol) code_power2=norm(passchan_ofdm_symbol2)^2/(length(passchan_ofdm_symbol2)); sgma1=sqrt(code_power1/(2*snr));%sgma如何计算，与当前SNR和信号平均能量有关系 sgma2=sqrt(code_power2/(2*snr)); [receive_ofdm_symbol1,awgn1]=addnoise(passchan_ofdm_symbol1,sgma1); % use randn [receive_ofdm_symbol2,awgn2]=addnoise(passchan_ofdm_symbol2,sgma2); % [receive_ofdm_symbol1,awgn1]=addnoise(ofdm_guard_interval_out_serial1,sgma1); % use randn % [receive_ofdm_symbol2,awgn2]=addnoise(ofdm_guard_interval_out_serial2,sgma2); % --------------------------------------------- % D: % +++++ RECEIVER +++++ % --------------------------------------------- % 1. The guard interval was removed from received signals ich4 and qch4 %remove函数里包含了串并转换 guard_interval_remove_out1=guard_interval_remove(receive_ofdm_symbol1,(fftlen+guard_internal),guard_internal,(number_ofdm_signal+pilot_num)); guard_interval_remove_out2=guard_interval_remove(receive_ofdm_symbol2,(fftlen+guard_internal),guard_internal,(number_ofdm_signal+pilot_num)); % 2. FFT transform fft_out11=fft(guard_interval_remove_out1); fft_out22=fft(guard_interval_remove_out2); % nomalize the power fft_out1=fft_out11./sqrt(fftlen); fft_out2=fft_out22./sqrt(fftlen); % 3. channel estimation and signal detection % LS and zero-force ls_zf_detect_sig1=ls_estimation(fft_out1,pilot_space,pilot_sequence1,pilot_num);%导频间隔pilot_space=5，pilot_sequence1为导频序列，导频个数pilot_num=10 ls_zf_detect_sig2=ls_estimation(fft_out2,pilot_space,pilot_sequence2,pilot_num); % LMMSE and zero-force lmmse_zf_detect_sig1=lmmse_estimation(fft_out1,pilot_space,pilot_sequence1,pilot_num,trms_1,t_max,snr); lmmse_zf_detect_sig2=lmmse_estimation(fft_out2,pilot_space,pilot_sequence2,pilot_num,trms_1,t_max,snr); %low_rank_lmmse and zero-force [low_rank_lmmse_sig,dlamdaa,dlamda_sor]=lr_lmmse_estimation(fft_out1,pilot_space,pilot_sequence1,pilot_num,trms_1,t_max,snr,guard_internal); % transform domain: DFT [DFT_sig1,LL,A2]=DFT_estimation(fft_out1,pilot_space,pilot_sequenc