BER OF M-ary PSK and M-ary QAM

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ABDUL 2020-10-1

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https://ww2.mathworks.cn/matlabcentral/answers/603034-ber-of-m-ary-psk-and-m-ary-qam

评论： ABDUL 2020-11-5

Dear All....

I am trying to write a program for the implementation of MIMO-OFDMby using wavelets transfrom . when i plot the BER Curve i am getting a straight line i am not able to get as a standard curve . any help will be appreciated.

Regards

Abdul Azeez

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ABDUL 2020-10-12

编辑：ABDUL 2020-10-12

在 MATLAB Online 中打开

hi.... find attached below code which i am trying to implement for the ofdm by using the wavelet transforms to plot the BER V/s SNR graph and the Peak to Average Power Ratio (PAPR) for the same . i am trying to plot the BER V/s SNR graph for which i am getting a straight line

Regards

Abdul Azeez

clc
clear all;
close all;
M = 4; % QPSK signal constellatio
N = 64; % number of subcarriers
fft_size = N; % have 128 data poexitint
nbits = 100; 
nDWTsym = ceil(nbits/N) ;% number of symbols for DWT system
nsym = nbits;
snr = 0:8;
% ------------------%
% TRANSMITTER          
% ------------------%
data_source=randsrc(1, fft_size*(nsym-2), 0:M-1); %the data source
sp = reshape(data_source,fft_size,nsym-2).';% s/p
% sp = reshape(qpsk_mod , fft_size, nsym-2);% s/p
[rdwt,cdwt] = size (sp);
tx_dwt= [];
for i=2:nsym-1
    for uu=1:cdwt
        qpsk_mod=pskmod(sp,M);
        DATADWT=qpsk_mod;
        AC = DATADWT(1:rdwt/2,uu);       % approximation coefficients
        DC = DATADWT(rdwt/2+1:rdwt,uu);  % detailed (wavelet) coefficients
        IDWT=idwt(AC,DC,'haar');         % IDWT process
        TXDWT(:,uu)= IDWT;               % transmitted data for DWT
    end
    %%% parallel to serial =======> to the channel
    ps1 = reshape( TXDWT,1,[]);
    ofdm_signal_dwt=TXDWT;
    pilot = zeros(size(TXDWT));
    Signal_Power_dwt = abs(ofdm_signal_dwt.^2);
    Peak_Power = max(Signal_Power_dwt,[],2);
    Mean_Power = mean(Signal_Power_dwt,2);
    PAPR_dwt = 10*log10(Peak_Power./Mean_Power);
    tx_dwt = [tx_dwt ofdm_signal_dwt];
end
figure (1)
[cdf0,PAPR0] = ccdf(PAPR_dwt,0.1);
semilogy(PAPR0,cdf0,'-b')
legend('DWT based MIMO OFDM System')
xlabel('PAPR0 [dB]');
ylabel('CCDF (Pr[PAPR>PAPR0])');
tt_dwt=reshape(TXDWT,1,[]);
tt_dwt =[ pilot tx_dwt pilot];
x_abs_dwt=abs(tt_dwt);
papr_dwt=10*log(max(x_abs_dwt.^2)/mean(x_abs_dwt.^2));
% ------------
% CHANNEL
% ------------
% ---------------
% RECEIVER
% ------------
no_of_error_dwt=[];
ratio_dwt=[];
for ii=1:length(snr)
    rx_dwt= [];
    rx_signal_matrix_dwt = reshape(ps1,rdwt,cdwt).';%98x64, 64x98
    [~, c] = size(rx_signal_matrix_dwt);
for j=1:cdwt
      A1=[];
      received_symbol=[];
      received_symbol_1=[];
      con_dwt=[];
      received_symbol_1=[];
      DWT=[];
      cd=[];
      RXDWT=[];
      channel = 1/sqrt(2)*[randn(1,length(rx_signal_matrix_dwt))+sqrt(-1)*randn(1,length(rx_signal_matrix_dwt))];
    %%% the transmitted signal is corrupted with addtive noise
      A1=channel.*rx_signal_matrix_dwt(j,:);
      received_symbol = awgn(A1, snr(ii));
% equalization:
      received_symbol = conj(channel).* received_symbol;   
% Convert Data back to "parallel" form to perform IDWT
con_dwt=reshape(received_symbol, 1,rdwt);
[DWT,cd]=dwt(con_dwt,'haar');%% DWT
        RXDWT=[DWT cd];% recieved data for DWT
%%% parallel to serial   
RXDWT1 = reshape(RXDWT.',1,[]);% at DWT
qpsk_demod=pskdemod(RXDWT,M);
rx_dwt =[rx_dwt  qpsk_demod];
end
% counting the errors and ratio 
[nDWT,rDWT]=biterr(data_source, rx_dwt);
simBerDWT(ii)=rDWT;%% DWT system
end 
figure (2)
theory_Pb_BPSK = (1/2)*erfc(sqrt(10.^(snr/10)));
semilogy(snr,theory_Pb_BPSK,'bs-','LineWidth',2);
hold on
semilogy(snr,simBerDWT,'mx-','LineWidth',2);
axis([0 8 10^-6 1]); grid on
legend('theory', 'simulation for DWT(Haar)','simulation for FFT');
xlabel('SNR, dB') ; ylabel('Bit Error Rate')
title('BER for qpsk using DWT based ofdm ')

ABDUL 2020-10-13

编辑：ABDUL 2020-10-13

it is 1x 64 only . if it can more generalised to 1xN data samples . it would be better .

ABDUL 2020-11-5

hi...

if i change the wavelet to other wavelets like db2,db3, sym2, sym3 my data is getting reduced for eg if i have a data of 1x64 , Ac will have 1x32 and Dc will have 1x32 through haar wavelet i will be getting a size of 1x64 but when i use other wavelet like db2 i will be getting the size for 1x30 for Ac and for Dc i will be getting 1x30 the total size of the data will be 1x60 how to retain the same size as 1x64 only when i use the wavelet of db2 and other wavelets

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