Azzera filtri
Azzera filtri

Hi i would like to ask how i reduce my ber value using FBMC modulation for my project the signal at receiver side is from oscillscope but ber is high . so can someone help me?

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d = rng(211); % Set RNG state for repeatability
numFFT = 256; % Number of FFT points
numGuards = 53; % 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 num of bit in one symbol
bitsinreceiver = 6;
snrdB = 15; % 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);
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;
% Store transmitted signals for all symbols
currSym = complex(symBuf(1:KF));
txSigAll(:,symIdx) = currSym;
txrealsignal=real(txSigAll);
tximgsignal=imag(txSigAll);
% real and imaginarysignal
A=(23.95*real(txSigAll(:,12)));
B=(23.95*imag(txSigAll(:,12)));
C=[A B];
end
scopesignal = 'C:\Users\User\Desktop\4096_ij.csv';
T =readmatrix(scopesignal);
receivesignal=resample(T,2,8);
% Process symbol-wise
for symIdx = 1:numSymbols
rxSig = receivesignal;
% Add WGN
%rxNsig = awgn(rxSig, snrdB, 'measured');%%no need later
% 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;
% De-mapper: Perform hard decision
rxBits(:, symIdx) = qamdemod(rcomb, 2^bitsPerSubCarrier, ...
'OutputType', 'bit', 'UnitAveragePower', true);
end
% Measure BER with appropriate delay
BER = comm.ErrorRate;
BER.ReceiveDelay = bitsPerSubCarrier*KL;%1200 receivedelay
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(d);
%%%%%%%%%%%%%%%%%RESULT
%%FBMC Reception for K = 4, BER = 0.49167 at SNR = 15 dB
%%I WISH TO REDUCE BER VALUE THANK YOU

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