ReComm
Member level 2
The following code is used to estimate and correct the frequency offset errors for a single carrier system
How can i adapt it for OFDM System?
Code:
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
freqOffset = 0; phaseOffset = 0;
hPFO = comm.PhaseFrequencyOffset('FrequencyOffset', freqOffset, ... 'PhaseOffset', phaseOffset, ... 'SampleRate', samplesPerSymbol/Ts);
rx_signal1l = step(hPFO,tx_signal);
rx_signal = rx_signal1l.';
hDelayInstFreq = dsp.Delay;
hMovAve = dsp.DigitalFilter('TransferFunction','FIR (all zeros)', ... 'Numerator', ones(1,100)/100);
hCumSum = dsp.CumulativeSum('Dimension','Channels (running sum)', ... 'FrameBasedProcessing', true);
%% Calculate the frequency shift estimate
P = 2;
currInstFreq = rx_signal.^(2*P);
prevInstFreq = step(hDelayInstFreq, currInstFreq);
freqShiftEst1 = currInstFreq .* conj(prevInstFreq);
% Average over 1 frame
freqShiftEst = mean(freqShiftEst1);
% Moving average over 100 frames
freqShiftEst = step(hMovAve, freqShiftEst);
freqShiftEst = angle(freqShiftEst) / (2*P);
% Convert digital frequency to Hertz
freqShiftEst = freqShiftEst / (2*pi*Ts);
%% Apply frequency correction
freqCorr = repmat(-freqShiftEst*Ts, samplesPerFrame, 1);
% Calculate cumulative phase shift
freqCorr = step(hCumSum, freqCorr);
% Apply frequency shift correction
rxSym = rx_signal .* exp(1i*2*pi*freqCorr);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%How can i adapt it for OFDM System?
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