Error in FBMC vs. OFDM Modulation of Mathworks

In this code, having a transmission without noise, the transmitted bits should be the same as the received bits.

The inpData variable is different than the rxBits variable. Example: inpData [1 0 1 1] .... rxBits [0 0 1 0]. Please help

s = rng(211);            % Set RNG state for repeatability

%%System Parameters

numFFT = 1024;           % Number of FFT points
numGuards = 212;         % Guard bands on both sides
K = 4;                   % Overlapping symbols, one of 2, 3, or 4
numSymbols = 8;        % Simulation length in symbols
bitsPerSubCarrier = 4;   % 2: 4QAM, 4: 16QAM, 6: 64QAM, 8: 256QAM
snrdB =0;              % SNR in dB

% Prototype filter
switch K
    case 2
        HkOneSided = sqrt(2)/2;
    case 3
        HkOneSided = [0.911438 0.411438];
    case 4
        HkOneSided = [0.971960 sqrt(2)/2 0.235147];
    otherwise
        return
end
% Build symmetric filter
Hk = [fliplr(HkOneSided) 1 HkOneSided];

% QAM symbol mapper
qamMapper = comm.RectangularQAMModulator(...
    'ModulationOrder', 2^bitsPerSubCarrier, ...
    'BitInput', true, ...
    'NormalizationMethod', 'Average power');

% Transmit-end processing
%   Initialize arrays
L = numFFT-2*numGuards;  % Number of complex symbols per OFDM symbol
KF = K*numFFT;
KL = K*L;
dataSubCar = zeros(L, 1);
dataSubCarUp = zeros(KL, 1);

sumFBMCSpec = zeros(KF*2, 1);
sumOFDMSpec = zeros(numFFT*2, 1);

numBits = bitsPerSubCarrier*L/2;    % account for oversampling by 2
inpData = zeros(numBits, numSymbols); 
rxBits = zeros(numBits, numSymbols);
txSigAll = complex(zeros(KF, numSymbols));
symBuf = complex(zeros(2*KF, 1));

% Loop over symbols
for symIdx = 1:numSymbols

      % Generate mapped symbol data
      inpData(:, symIdx) = randi([0 1], numBits, 1);
      modData = qamMapper(inpData(:, symIdx));

      % OQAM Modulator: alternate real and imaginary parts
      if rem(symIdx,2)==1     % Odd symbols
          dataSubCar(1:2:L) = real(modData);
          dataSubCar(2:2:L) = 1i*imag(modData);
      else                    % Even symbols
          dataSubCar(1:2:L) = 1i*imag(modData);
          dataSubCar(2:2:L) = real(modData);
      end

      % Upsample by K, pad with guards, and filter with the prototype filter
      dataSubCarUp(1:K:end) = dataSubCar;
      dataBitsUpPad = [zeros(numGuards*K,1); dataSubCarUp; zeros(numGuards*K,1)];
      X1 = filter(Hk, 1, dataBitsUpPad);
      % Remove 1/2 filter length delay
      X = [X1(K:end); zeros(K-1,1)];

      % Compute IFFT of length KF for the transmitted symbol
      txSymb = fftshift(ifft(X));

      % Transmitted signal is a sum of the delayed real, imag symbols
      symBuf = [symBuf(numFFT/2+1:end); complex(zeros(numFFT/2,1))];
      symBuf(KF+(1:KF)) = symBuf(KF+(1:KF)) + txSymb;

      % Compute power spectral density (PSD)
      currSym = complex(symBuf(1:KF));
      [specFBMC, fFBMC] = periodogram(currSym, hann(KF, 'periodic'), KF*2, 1);
      sumFBMCSpec = sumFBMCSpec + specFBMC;

      % Store transmitted signals for all symbols
      txSigAll(:,symIdx) = currSym;
  end

% Plot power spectral density
sumFBMCSpec = sumFBMCSpec/mean(sumFBMCSpec(1+K+2*numGuards*K:end-2*numGuards*K-K));
plot(fFBMC-0.5,10*log10(sumFBMCSpec));
grid on
axis([-0.5 0.5 -180 10]);
xlabel('Normalized frequency'); 
ylabel('PSD (dBW/Hz)')
title(['FBMC, K = ' num2str(K) ' overlapped symbols'])
set(gcf, 'Position', figposition([15 50 30 30]));

for symIdx = 1:numSymbols

      inpData2 = randi([0 1], bitsPerSubCarrier*L, 1);
      modData = qamMapper(inpData2);

      symOFDM = [zeros(numGuards,1); modData; zeros(numGuards,1)];
      ifftOut = sqrt(numFFT).*ifft(ifftshift(symOFDM));

      [specOFDM,fOFDM] = periodogram(ifftOut, rectwin(length(ifftOut)), ...
          numFFT*2, 1, 'centered'); 
      sumOFDMSpec = sumOFDMSpec + specOFDM;
  end

% Plot power spectral density (PSD) over all subcarriers
sumOFDMSpec = sumOFDMSpec/mean(sumOFDMSpec(1+2*numGuards:end-2*numGuards));
figure; 
plot(fOFDM,10*log10(sumOFDMSpec)); 
grid on
axis([-0.5 0.5 -180 10]);
xlabel('Normalized frequency'); 
ylabel('PSD (dBW/Hz)')
title(['OFDM, numFFT = ' num2str(numFFT)])
set(gcf, 'Position', figposition([46 50 30 30]));

% QAM demodulator
qamDemod = comm.RectangularQAMDemodulator(...
    'ModulationOrder', 2^bitsPerSubCarrier, ...
    'BitOutput', true, ...
    'NormalizationMethod', 'Average power');
BER = comm.ErrorRate;

% Process symbol-wise
for symIdx = 1:numSymbols
    rxSig = txSigAll(:, symIdx);

      % Add WGN
      %rxNsig = awgn(rxSig, snrdB, 'measured');

      % Perform FFT
      rxf = fft(fftshift(rxSig));

      % Matched filtering with prototype filter
      rxfmf = filter(Hk, 1, rxf);
      % Remove K-1 delay elements
      rxfmf = [rxfmf(K:end); zeros(K-1,1)];
      % Remove guards
      rxfmfg = rxfmf(numGuards*K+1:end-numGuards*K);

      % OQAM post-processing
      %  Downsample by 2K, extract real and imaginary parts
      if rem(symIdx, 2)
          % Imaginary part is K samples after real one
          r1 = real(rxfmfg(1:2*K:end));
          r2 = imag(rxfmfg(K+1:2*K:end));
          rcomb = complex(r1, r2);
      else
          % Real part is K samples after imaginary one
          r1 = imag(rxfmfg(1:2*K:end));
          r2 = real(rxfmfg(K+1:2*K:end));
          rcomb = complex(r2, r1);
      end
      %  Normalize by the upsampling factor
      rcomb = (1/K)*rcomb;

      % Demapper: Perform hard decision
      rxBits(:, symIdx) = qamDemod(rcomb);    
  end

% Measure BER with appropriate delay
BER.ReceiveDelay = bitsPerSubCarrier*KL;
ber = BER(inpData(:), rxBits(:));

% Display Bit error
disp(['FBMC Reception for K = ' num2str(K) ', BER = ' num2str(ber(1)) ...
    ' at SNR = ' num2str(snrdB) ' dB'])

% Restore RNG state
rng(s);

[abdullah qasim]

same problem

Answer 1

[mohamed elganiny]

Dear / Aaron Hughes

please, i want to know the purpose of the following two line in this code and briefly how these two lines work

i know that is related to sum and overlap block as mentioned in the code description but Unfortunately it is not clear for me to understand.

% Transmitted signal is a sum of the delayed real, imag symbols

symBuf = [symBuf(numFFT/2+1:end); complex(zeros(numFFT/2,1))];

symBuf(KF+(1:KF)) = symBuf(KF+(1:KF)) + txSymb;

thanks in advance

Answer 2

[abdullah qasim]

this code calculates BER for one sample, not for all samples so give one value for BER.

so we must do it loop (for loop) to calculate all values of ber and give the full sketch to BER to SNR

[Peter Liu]

Hi. Do you know why it measures BER with the delay bitsPerSubCarrier*KL ? Does it mean that all the recieved data lags behind the transmitted data by bitsPerSubCarrier*KL samples?

Answer 3

[Aaron Hughes]

Original article is here https://www.mathworks.com/help/comm/ug/fbmc-vs-ofdm-modulation.html

The "magic" of this code happens here

% Measure BER with appropriate delay <-- notice it says with appropriate "delay"

%BER.ReceiveDelay = bitsPerSubCarrier*KL; <-- if you comment out this line

like I did here, you'll get

the behavior you're reporting

ber = BER(inpData(:), rxBits(:)); ß this will report nearly 50% error rate

Because you are doing this

sum( rxBits(:,symIdx) ~= inpData(:,symIdx) )

But the way FBMC works, is there’s a delay due to the overlapping of symbols.

BER.ReceiveDelay = bitsPerSubCarrier*KL; ß That’s why there’s this

ber = BER(inpData(:), rxBits(:)); ß This will now report 0 errors

For example, if BER.ReceiveDelay=4800 and you’re sending 600 bits each symbol, then this is a delay of 4800/600 = 8 symbols.

This means you need to compare this

sum( rxBits(:,symIdx) ~= inpData(:,symIdx-8) )

And I’ve verified the code works!

===========================================================================

This code below will have the ERRORS you reported using the code above I just explained,

AND comm.ErrorRate will report this too

s = rng(211); % Set RNG state for repeatability

numFFT = 1024; % Number of FFT points

numGuards = 212; % Guard bands on both sides

K = 4; % Overlapping symbols, one of 2, 3, or 4

numSymbols = 100; % Simulation length in symbols

bitsPerSubCarrier = 2; % 2: 4QAM, 4: 16QAM, 6: 64QAM, 8: 256QAM

snrdB = 45; % SNR in dB

% Prototype filter

switch K

case 2

HkOneSided = sqrt(2)/2;

case 3

HkOneSided = [0.911438 0.411438];

case 4

HkOneSided = [0.971960 sqrt(2)/2 0.235147];

otherwise

return

end

% Build symmetric filter

Hk = [fliplr(HkOneSided) 1 HkOneSided];

% Transmit-end processing

% Initialize arrays

L = numFFT-2*numGuards; % Number of complex symbols per OFDM symbol

KF = K*numFFT;

KL = K*L;

dataSubCar = zeros(L, 1);

dataSubCarUp = zeros(KL, 1);

sumFBMCSpec = zeros(KF*2, 1);

sumOFDMSpec = zeros(numFFT*2, 1);

numBits = bitsPerSubCarrier*L/2; % account for oversampling by 2

inpData = zeros(numBits, numSymbols);

rxBits = zeros(numBits, numSymbols);

txSigAll = complex(zeros(KF, numSymbols));

symBuf = complex(zeros(2*KF, 1));

% Loop over symbols

for symIdx = 1:numSymbols

% Generate mapped symbol data

inpData(:, symIdx) = randi([0 1], numBits, 1);

modData = qammod(inpData(:, symIdx), 2^bitsPerSubCarrier, ...

'InputType', 'Bit', 'UnitAveragePower', true);

% OQAM Modulator: alternate real and imaginary parts

if rem(symIdx,2)==1 % Odd symbols

dataSubCar(1:2:L) = real(modData);

dataSubCar(2:2:L) = 1i*imag(modData);

else % Even symbols

dataSubCar(1:2:L) = 1i*imag(modData);

dataSubCar(2:2:L) = real(modData);

end

% Upsample by K, pad with guards, and filter with the prototype filter

dataSubCarUp(1:K:end) = dataSubCar;

dataBitsUpPad = [zeros(numGuards*K,1); dataSubCarUp; zeros(numGuards*K,1)];

X1 = filter(Hk, 1, dataBitsUpPad);

% Remove 1/2 filter length delay

X = [X1(K:end); zeros(K-1,1)];

% Compute IFFT of length KF for the transmitted symbol

txSymb = fftshift(ifft(X));

% Transmitted signal is a sum of the delayed real, imag symbols

symBuf = [symBuf(numFFT/2+1:end); complex(zeros(numFFT/2,1))];

symBuf(KF+(1:KF)) = symBuf(KF+(1:KF)) + txSymb;

% Compute power spectral density (PSD)

currSym = complex(symBuf(1:KF));

[specFBMC, fFBMC] = periodogram(currSym, hann(KF, 'periodic'), KF*2, 1);

sumFBMCSpec = sumFBMCSpec + specFBMC;

% Store transmitted signals for all symbols

txSigAll(:,symIdx) = currSym;

end

% Plot power spectral density

sumFBMCSpec = sumFBMCSpec/mean(sumFBMCSpec(1+K+2*numGuards*K:end-2*numGuards*K-K));

plot(fFBMC-0.5,10*log10(sumFBMCSpec));

grid on

axis([-0.5 0.5 -180 10]);

xlabel('Normalized frequency');

ylabel('PSD (dBW/Hz)')

title(['FBMC, K = ' num2str(K) ' overlapped symbols'])

set(gcf, 'Position', figposition([15 50 30 30]));

for symIdx = 1:numSymbols

inpData2 = randi([0 1], bitsPerSubCarrier*L, 1);

modData = qammod(inpData2, 2^bitsPerSubCarrier, ...

'InputType', 'Bit', 'UnitAveragePower', true);

symOFDM = [zeros(numGuards,1); modData; zeros(numGuards,1)];

ifftOut = sqrt(numFFT).*ifft(ifftshift(symOFDM));

[specOFDM,fOFDM] = periodogram(ifftOut, rectwin(length(ifftOut)), ...

numFFT*2, 1, 'centered');

sumOFDMSpec = sumOFDMSpec + specOFDM;

end

% Plot power spectral density (PSD) over all subcarriers

sumOFDMSpec = sumOFDMSpec/mean(sumOFDMSpec(1+2*numGuards:end-2*numGuards));

figure;

plot(fOFDM,10*log10(sumOFDMSpec));

grid on

axis([-0.5 0.5 -180 10]);

xlabel('Normalized frequency');

ylabel('PSD (dBW/Hz)')

title(['OFDM, numFFT = ' num2str(numFFT)])

set(gcf, 'Position', figposition([46 50 30 30]));

BER = comm.ErrorRate;

TotalBitsInError = 0;

TotalBits = 0;

% Process symbol-wise

for symIdx = 1:numSymbols

rxSig = txSigAll(:, symIdx);

% Add WGN

rxNsig = awgn(rxSig, snrdB, 'measured');

% Perform FFT

rxf = fft(fftshift(rxNsig));

% Matched filtering with prototype filter

rxfmf = filter(Hk, 1, rxf);

% Remove K-1 delay elements

rxfmf = [rxfmf(K:end); zeros(K-1,1)];

% Remove guards

rxfmfg = rxfmf(numGuards*K+1:end-numGuards*K);

% OQAM post-processing

% Downsample by 2K, extract real and imaginary parts

if rem(symIdx, 2)

% Imaginary part is K samples after real one

r1 = real(rxfmfg(1:2*K:end));

r2 = imag(rxfmfg(K+1:2*K:end));

rcomb = complex(r1, r2);

else

% Real part is K samples after imaginary one

r1 = imag(rxfmfg(1:2*K:end));

r2 = real(rxfmfg(K+1:2*K:end));

rcomb = complex(r2, r1);

end

% Normalize by the upsampling factor

rcomb = (1/K)*rcomb;

% De-mapper: Perform hard decision

rxBits(:, symIdx) = qamdemod(rcomb, 2^bitsPerSubCarrier, ...

'OutputType', 'bit', 'UnitAveragePower', true);

NumBitsInError = sum( rxBits(:,symIdx) ~= inpData(:,symIdx) );

fprintf('symIdx=%3d had %3d bits in error out of %d bits which is %.2f%% error rate\n',symIdx,NumBitsInError,length(inpData(:,symIdx)),100*NumBitsInError/length(inpData(:,symIdx)));

symIdx = symIdx;

TotalBitsInError = TotalBitsInError + NumBitsInError;

TotalBits = TotalBits + length(inpData(:,symIdx));

end

% Measure BER with appropriate delay

%BER.ReceiveDelay = bitsPerSubCarrier*KL;

ber = BER(inpData(:), rxBits(:));

% Display Bit error

disp(['FBMC Reception for K = ' num2str(K) ', BER = ' num2str(ber(1)) ...

' at SNR = ' num2str(snrdB) ' dB'])

fprintf('Total Bits in error is %d out of %d bits, BER=%.2f%%\n',ber(2),ber(3),100*ber(2)/ber(3));

fprintf('Total Bits in error is %d out of %d bits, BER=%.2f%%\n',TotalBitsInError,TotalBits,100*TotalBitsInError/TotalBits);

% Restore RNG state

rng(s);

Output looks like this

symIdx= 94 had 293 bits in error out of 600 bits which is 48.83% error rate

symIdx= 95 had 309 bits in error out of 600 bits which is 51.50% error rate

symIdx= 96 had 310 bits in error out of 600 bits which is 51.67% error rate

symIdx= 97 had 307 bits in error out of 600 bits which is 51.17% error rate

symIdx= 98 had 310 bits in error out of 600 bits which is 51.67% error rate

symIdx= 99 had 301 bits in error out of 600 bits which is 50.17% error rate

symIdx=100 had 310 bits in error out of 600 bits which is 51.67% error rate

FBMC Reception for K = 4, BER = 0.49973 at SNR = 45 dB

Total Bits in error is 29984 out of 60000 bits, BER=49.97%

Total Bits in error is 29984 out of 60000 bits, BER=49.97%

===========================================================================

This code below will NOT have the errors you reported because I’m incorporating the delay

s = rng(211); % Set RNG state for repeatability

numFFT = 1024; % Number of FFT points

numGuards = 212; % Guard bands on both sides

K = 4; % Overlapping symbols, one of 2, 3, or 4

numSymbols = 100; % Simulation length in symbols

bitsPerSubCarrier = 2; % 2: 4QAM, 4: 16QAM, 6: 64QAM, 8: 256QAM

snrdB = 45; % SNR in dB

% Prototype filter

switch K

case 2

HkOneSided = sqrt(2)/2;

case 3

HkOneSided = [0.911438 0.411438];

case 4

HkOneSided = [0.971960 sqrt(2)/2 0.235147];

otherwise

return

end

% Build symmetric filter

Hk = [fliplr(HkOneSided) 1 HkOneSided];

% Transmit-end processing

% Initialize arrays

L = numFFT-2*numGuards; % Number of complex symbols per OFDM symbol

KF = K*numFFT;

KL = K*L;

dataSubCar = zeros(L, 1);

dataSubCarUp = zeros(KL, 1);

sumFBMCSpec = zeros(KF*2, 1);

sumOFDMSpec = zeros(numFFT*2, 1);

numBits = bitsPerSubCarrier*L/2; % account for oversampling by 2

inpData = zeros(numBits, numSymbols);

rxBits = zeros(numBits, numSymbols);

txSigAll = complex(zeros(KF, numSymbols));

symBuf = complex(zeros(2*KF, 1));

% Loop over symbols

for symIdx = 1:numSymbols

% Generate mapped symbol data

inpData(:, symIdx) = randi([0 1], numBits, 1);

modData = qammod(inpData(:, symIdx), 2^bitsPerSubCarrier, ...

'InputType', 'Bit', 'UnitAveragePower', true);

% OQAM Modulator: alternate real and imaginary parts

ifrem(symIdx,2)==1 % Odd symbols

dataSubCar(1:2:L) = real(modData);

dataSubCar(2:2:L) = 1i*imag(modData);

else % Even symbols

dataSubCar(1:2:L) = 1i*imag(modData);

dataSubCar(2:2:L) = real(modData);

end

% Upsample by K, pad with guards, and filter with the prototype filter

dataSubCarUp(1:K:end) = dataSubCar;

dataBitsUpPad = [zeros(numGuards*K,1); dataSubCarUp; zeros(numGuards*K,1)];

X1 = filter(Hk, 1, dataBitsUpPad);

% Remove 1/2 filter length delay

X = [X1(K:end); zeros(K-1,1)];

% Compute IFFT of length KF for the transmitted symbol

txSymb = fftshift(ifft(X));

% Transmitted signal is a sum of the delayed real, imag symbols

symBuf = [symBuf(numFFT/2+1:end); complex(zeros(numFFT/2,1))];

symBuf(KF+(1:KF)) = symBuf(KF+(1:KF)) + txSymb;

% Compute power spectral density (PSD)

currSym = complex(symBuf(1:KF));

[specFBMC, fFBMC] = periodogram(currSym, hann(KF, 'periodic'), KF*2, 1);

sumFBMCSpec = sumFBMCSpec + specFBMC;

% Store transmitted signals for all symbols

txSigAll(:,symIdx) = currSym;

end

% Plot power spectral density

sumFBMCSpec = sumFBMCSpec/mean(sumFBMCSpec(1+K+2*numGuards*K:end-2*numGuards*K-K));

plot(fFBMC-0.5,10*log10(sumFBMCSpec));

grid on

axis([-0.5 0.5 -180 10]);

xlabel('Normalized frequency');

ylabel('PSD (dBW/Hz)')

title(['FBMC, K = ' num2str(K) ' overlapped symbols'])

set(gcf, 'Position', figposition([15 50 30 30]));

for symIdx = 1:numSymbols

inpData2 = randi([0 1], bitsPerSubCarrier*L, 1);

modData = qammod(inpData2, 2^bitsPerSubCarrier, ...

'InputType', 'Bit', 'UnitAveragePower', true);

symOFDM = [zeros(numGuards,1); modData; zeros(numGuards,1)];

ifftOut = sqrt(numFFT).*ifft(ifftshift(symOFDM));

[specOFDM,fOFDM] = periodogram(ifftOut, rectwin(length(ifftOut)), ...

numFFT*2, 1, 'centered');

sumOFDMSpec = sumOFDMSpec + specOFDM;

end

% Plot power spectral density (PSD) over all subcarriers

sumOFDMSpec = sumOFDMSpec/mean(sumOFDMSpec(1+2*numGuards:end-2*numGuards));

figure;

plot(fOFDM,10*log10(sumOFDMSpec));

grid on

axis([-0.5 0.5 -180 10]);

xlabel('Normalized frequency');

ylabel('PSD (dBW/Hz)')

title(['OFDM, numFFT = ' num2str(numFFT)])

set(gcf, 'Position', figposition([46 50 30 30]));

BER = comm.ErrorRate;

TotalBitsInError = 0;

TotalBits = 0;

% Process symbol-wise

for symIdx = 1:numSymbols

rxSig = txSigAll(:, symIdx);

% Add WGN

rxNsig = awgn(rxSig, snrdB, 'measured');

% Perform FFT

rxf = fft(fftshift(rxNsig));

% Matched filtering with prototype filter

rxfmf = filter(Hk, 1, rxf);

% Remove K-1 delay elements

rxfmf = [rxfmf(K:end); zeros(K-1,1)];

% Remove guards

rxfmfg = rxfmf(numGuards*K+1:end-numGuards*K);

% OQAM post-processing

% Downsample by 2K, extract real and imaginary parts

if rem(symIdx, 2)

% Imaginary part is K samples after real one

r1 = real(rxfmfg(1:2*K:end));

r2 = imag(rxfmfg(K+1:2*K:end));

rcomb = complex(r1, r2);

else

% Real part is K samples after imaginary one

r1 = imag(rxfmfg(1:2*K:end));

r2 = real(rxfmfg(K+1:2*K:end));

rcomb = complex(r2, r1);

end

% Normalize by the upsampling factor

rcomb = (1/K)*rcomb;

% De-mapper: Perform hard decision

rxBits(:, symIdx) = qamdemod(rcomb, 2^bitsPerSubCarrier, ...

'OutputType', 'bit', 'UnitAveragePower', true);

if symIdx>8

NumBitsInError = sum( rxBits(:,symIdx) ~= inpData(:,symIdx-8) );

fprintf('symIdx=%3d had %3d bits in error out of %d bits which is %.2f%% error rate\n',symIdx,NumBitsInError,length(inpData(:,symIdx)),100*NumBitsInError/length(inpData(:,symIdx)));

TotalBitsInError = TotalBitsInError + NumBitsInError;

TotalBits = TotalBits + length(inpData(:,symIdx));

end

symIdx = symIdx;

end

% Measure BER with appropriate delay

BER.ReceiveDelay = bitsPerSubCarrier*KL;

ber = BER(inpData(:), rxBits(:));

% Display Bit error

disp(['FBMC Reception for K = ' num2str(K) ', BER = ' num2str(ber(1)) ...

' at SNR = ' num2str(snrdB) ' dB'])

fprintf('Total Bits in error is %d out of %d bits, BER=%.2f%%\n',ber(2),ber(3),100*ber(2)/ber(3));

fprintf('Total Bits in error is %d out of %d bits, BER=%.2f%%\n',TotalBitsInError,TotalBits,100*TotalBitsInError/TotalBits);

% Restore RNG state

rng(s);

Output looks like this

symIdx= 94 had 0 bits in error out of 600 bits which is 0.00% error rate

symIdx= 95 had 0 bits in error out of 600 bits which is 0.00% error rate

symIdx= 96 had 0 bits in error out of 600 bits which is 0.00% error rate

symIdx= 97 had 0 bits in error out of 600 bits which is 0.00% error rate

symIdx= 98 had 0 bits in error out of 600 bits which is 0.00% error rate

symIdx= 99 had 0 bits in error out of 600 bits which is 0.00% error rate

symIdx=100 had 0 bits in error out of 600 bits which is 0.00% error rate

FBMC Reception for K = 4, BER = 0 at SNR = 45 dB

Total Bits in error is 0 out of 55200 bits, BER=0.00%

Total Bits in error is 0 out of 55200 bits, BER=0.00%

[Aaron Hughes]

What's the error?

[abdullah qasim]

thank you but this 50% of BER not reach to zero

Answer 4

[Aaron Hughes]

Sorry I don't understand your question.

But please notice there are 2 versions of the code I added above.

Version 1 will have an output like this

symIdx= 99 had 301 bits in error out of 600 bits which is 50.17% error rate

symIdx=100 had 310 bits in error out of 600 bits which is 51.67% error rate

FBMC Reception for K = 4, BER = 0.49973 at SNR = 45 dB

Total Bits in error is 29984 out of 60000 bits, BER=49.97%

Total Bits in error is 29984 out of 60000 bits, BER=49.97%

Version 2 will have an output like this

symIdx= 99 had 0 bits in error out of 600 bits which is 0.00% error rate

symIdx=100 had 0 bits in error out of 600 bits which is 0.00% error rate

FBMC Reception for K = 4, BER = 0 at SNR = 45 dB

Total Bits in error is 0 out of 55200 bits, BER=0.00%

Total Bits in error is 0 out of 55200 bits, BER=0.00%

Also I do see a syntax error in the code I added.

Looks like the rich text editor removed a space on me.

ifrem(symIdx,2)==1 % Odd symbols

should be

if rem(symIdx,2)==1 % Odd symbols

[abdullah qasim]

I mean, the first version BER does not reach zero

[Aaron Hughes]

The first version BER is not supposed to reach zero.

The first version is showing what happens if you don't take the delay into account, which is you get a BER of 50%.

The second version does take the delay into account, and you get a BER of 0%.

In this FBMC example, there are K=4 symbols overlapped which amounts to a processing delay of 2*K=8 symbol delay at the receiver.

NumBitsInError = sum( rxBits(:,symIdx) ~= inpData(:,symIdx-0) ); <-- Version 1 delay=0

NumBitsInError = sum( rxBits(:,symIdx) ~= inpData(:,symIdx-8) ); <-- Version 2 delay=8

[kim zheng cho]

Hi, i would like to ask if let said i want to process more than one symbol how should i modified the code?Since 1 symbol is 4096 point if let said i want to process two symbol in column which 8192 point/data bits how should i done it? As the left side must equal to right side . Thank you.....