DVB-S2 Receiver Using Software-Defined Radio

This example uses:

Satellite Communications Toolbox Satellite Communications Toolbox
Communications Toolbox Support Package for Analog Devices ADALM-PLUTO Radio Communications Toolbox Support Package for Analog Devices ADALM-PLUTO Radio
Communications Toolbox Support Package for USRP Radio Communications Toolbox Support Package for USRP Radio

This example shows how to capture Digital Video Broadcasting Satellite Second Generation (DVB-S2) waveforms using the software-defined radio (SDR) device. The example then shows you how to perform synchronization, demodulation, and decoding of the received waveform, and measure the packet error rate (PER). To generate and transmit DVB-S2 waveforms, see the DVB-S2 Transmitter Using Software-Defined Radio example, and configure your test environment with:

Two SDR platforms connected to the same host computer. You must run two MATLAB® sessions, one for transmission and another for reception.
Two SDR platforms connected to different host computers. You must run a MATLAB® session on each, one for transmission and another for reception.

Introduction

For this example, use the comm.SDRuReceiver or sdrrx System object™ to receive data corrupted by over-the-air transmission at a sample rate of 2 Msps. The receiver design consists of matched filtering, symbol timing synchronization, frame synchronization, and carrier synchronization. To decode the physical layer (PL) frames, the receiver recovers the physical layer transmission parameters such as modulation scheme, code rate, and forward error correction (FEC) frame type from the PL header. To regenerate the input bit stream, receiver decodes the baseband (BB) header. Every baseband frame is a concatenation of user packets. The receiver returns the cyclic redundancy check (CRC) status of each packet is returned along with the decoded bits, and then measures the PER.

If you don't have an SDR device to capture the waveform, this example supports importing a file with a captured waveform.

This diagram summarizes the reception process.

For details on receiver design, see the End-to-End DVB-S2 Simulation with RF Impairments and Corrections example.

This example supports these SDRs for capturing the waveform.

ADALM-PLUTO (requires Communications Toolbox™ Support Package for Analog Devices® ADALM-PLUTO Radio)
USRP™ B200/B210/N200/N210/USRP2 (requires Communications Toolbox Support Package for USRP™ Radio)

Download DVB-S2 LDPC Parity Matrices Data Set

Load a MAT file containing DVB-S2 LDPC parity matrices. If the MAT file is not available on the MATLAB® path, use these commands to download and unzip the MAT file.

if ~exist('dvbs2xLDPCParityMatrices.mat','file')
    if ~exist('s2xLDPCParityMatrices.zip','file')
        url = 'https://ssd.mathworks.com/supportfiles/spc/satcom/DVB/s2xLDPCParityMatrices.zip';
        websave('s2xLDPCParityMatrices.zip',url);
        unzip('s2xLDPCParityMatrices.zip');
    end
    addpath('s2xLDPCParityMatrices');
end

Example Setup

To receive a waveform off the air, set useSDR to true. To import a waveform from a MAT file, set useSDR to false.

useSDR = false;

Specify the filename of a precaptured waveform to the fileName variable.

fileName = "capturedDVBS2Waveform.mat";

If you set useSDR to true, configure the variables required for SDR reception.

if useSDR
    rxsim.DeviceName = "B200";
    rxsim.RadioCenterFrequency = 915e6;
    rxsim.RadioGain = 20;
end

Initialize Receiver Parameters

At the receiver, you first perform DC offset compensation, followed by automatic gain control (AGC), symbol timing synchronization, and then frame synchronization, in order. The receiver algorithms include coarse and fine frequency impairment correction algorithms. The preferred loop bandwidth for symbol timing and coarse frequency compensation depends on the $E_{s} / N_{o}$ setting. If the captured signal is buried under noise, you can reduce the loop bandwidth to filter out more noise during acquisition. The number of frames required for the symbol synchronization and frame synchronization depends on the loop bandwidth setting.

Set rxParams.symbSyncLock to ceil(1e5/rxParams.plFrameSize) for signals heavily corrupted by noise. For signals whose SNR is less than 1 dB, set rxParams.frameSyncLock to a value in the range of [5, 15] frames. Set these fields of the rxParams structure for synchronization processing. Set valid values for fecFrame, modCod, Fsamp, and Rsym, for proper capture and validation of the demodulated signal.

fecFrame = "short";                             % DVB-S2 FECFrame type
modCod = 24;                                    % 32APSK 3/4
Fsamp = 2e6;                                    % Sampling rate in samples per second
Rsym = 1e6;                                     % Symbol rate in symbols per second
sps = Fsamp/Rsym;

rxParams = getRxParams(fecFrame,modCod);
rxParams.carrSyncLoopBW            = 1e-3;      % Coarse frequency estimator loop bandwidth normalized by symbol rate
rxParams.symbSyncLoopBW            = 1e-4;      % Symbol timing synchronizer loop bandwidth normalized by symbol rate
rxParams.symbSyncLock              = 2;         % Number of frames required for symbol timing error convergence
rxParams.frameSyncLock             = 1;         % Number of frames required for frame synchronization
rxParams.sps = sps;
% Total frames taken for symbol timing and frame synchronization to happen
rxParams.initialTimeSync = rxParams.symbSyncLock + rxParams.frameSyncLock;

Capture DVB-S2 Waveform Using SDR

Discover radio(s) connected to your computer. This example uses the first SDR radio found using the rxsim.DeviceName and findsdru function. Check if the radio is available and record the radio type. Initialize sdrrx or comm.SDRuReceiver System object. Set the platform, center frequency, sample rate, gain, and other relevant properties. Receive the DVB-S2 waveform over-the-air using the SDR device.

numFrames = 50;                                                  % Number of PL frames to capture
enableBurstMode       = true;
numFramesInBurst      = numFrames;
if useSDR
    if matches(rxsim.DeviceName,"Pluto")
        radioRx = sdrrx("Pluto");
        radioRx.RadioID               = "usb:0";
        radioRx.CenterFrequency       = rxsim.RadioCenterFrequency;
        radioRx.BasebandSampleRate    = Fsamp;
        radioRx.GainSource            = "Manual";
    else
        connectedRadios = findsdru;
        rIdx = find(strcmp(rxsim.DeviceName,{connectedRadios.Platform}));
        if strcmp(connectedRadios(rIdx).Status,"Success")
            usrpRx.Platform = connectedRadios(rIdx).Platform;
            switch usrpRx.Platform
                case {'B200','B210'}
                    usrpRx.SerialNum = connectedRadios(rIdx).SerialNum;
                    usrpRx.MasterClockRate = 20e6;
                case 'N200/N210/USRP2'
                    usrpRx.IPAddress = connectedRadios(rIdx).IPAddress;
                    usrpRx.MasterClockRate = 100e6;
                otherwise
                    error("%s\n","Unsupported USRP device");
            end
        end
    
    switch usrpRx.Platform
        case {'B200','B210'}
            radioRx = comm.SDRuReceiver( ...
                Platform         =    usrpRx.Platform, ...
                SerialNum        =    usrpRx.SerialNum, ...
                CenterFrequency  =    rxsim.RadioCenterFrequency, ...
                MasterClockRate  =    usrpRx.MasterClockRate, ...
                DecimationFactor =    usrpRx.MasterClockRate/Fsamp);
        case 'N200/N210/USRP2'
            radioRx = comm.SDRuReceiver( ...
                Platform         =   usrpRx.Platform, ...
                IPAddress        =   usrpRx.IPAddress, ...
                CenterFrequency  =   rxsim.RadioCenterFrequency, ...
                MasterClockRate  =   usrpRx.MasterClockRate, ...
                DecimationFactor =   usrpRx.MasterClockRate/Fsamp);      
    end
    end
    radioRx.Gain                 = rxsim.RadioGain;                            % In dB
    radioRx.OutputDataType       = "double";
    radioRx.SamplesPerFrame      = rxParams.plFrameSize*sps;
    if enableBurstMode
        radioRx.EnableBurstMode  = enableBurstMode;
        radioRx.NumFramesInBurst = numFramesInBurst;
    end
    disp(radioRx)
    rxLength   = numFrames*radioRx.SamplesPerFrame;
    rxIn       = zeros(rxLength,1) + 1i*zeros(rxLength,1);
    for l = 1:numFrames
        [rxIn((l-1)*radioRx.SamplesPerFrame+1:l*radioRx.SamplesPerFrame),numSamps,overrun] = radioRx();
        if overrun && ~usrpRx.EnableBurstMode
            fprintf("Overrun detected in loop #%d\n",l);
        end
    end
    release(radioRx);

Import Waveform from File

This section loads the DVB-S2 data from a MAT file.

else
    fprintf("Reading DVB-S2 IQ data from a captured file\n")
    load(fileName) 
end

Reading DVB-S2 IQ data from a captured file

rxIn = rxIn./(max(abs(rxIn)));
rxParams.initialTimeFreqSync = numFrames;
rxParams.totalSyncFrames = numFrames;

Visualize Received Waveform

Visualize the spectrum of the captured waveform and its constellation.

specAn = spectrumAnalyzer(SampleRate=Fsamp);
specAn(rxIn(1:100000));

rxConst = comm.ConstellationDiagram(Title="Received data", ...
    XLimits=[-1 1],YLimits=[-1 1], ...
    ShowReferenceConstellation=false, ...
    SamplesPerSymbol=rxParams.sps);
rxConst(rxIn(1:100000))

Initialize Receiver Processing System Objects

Create a time and coarse frequency synchronization System object by using the HelperDVBS2TimeFreqSynchronizer helper object. Initialize the comm.AGC, dsp.DCBlocker, and comm.ConstellationDiagram System objects.

timeFreqSync = HelperDVBS2TimeFreqSynchronizer( ...
    CarrSyncLoopBW=rxParams.carrSyncLoopBW, ...
    SymbSyncLoopBW=rxParams.symbSyncLoopBW, ...
    SamplesPerSymbol=rxParams.sps, ...
    DataFrameSize=rxParams.xFecFrameSize, ...
    SymbSyncTransitFrames=rxParams.symbSyncLock, ...
    FrameSyncAveragingFrames=rxParams.frameSyncLock);

agc = comm.AGC(AveragingLength=2000,AdaptationStepSize = 0.001);

dcBlock = dsp.DCBlocker(Algorithm="FIR",Length=100); 

syncConst = comm.ConstellationDiagram(Title="Synchronized data", ...
     XLimits=[-2 2], ...
     YLimits=[-2 2], ...
    ShowReferenceConstellation = false);
[numFramesLost,pktsErr,bitsErr,pktsRec,stIdx,numFreqEst] = deal(0);

% Initialize data indexing variables
plFrameSize = rxParams.plFrameSize;
symSyncOutLen = zeros(rxParams.initialTimeFreqSync,1);
freqCounter = 0;
isCoarseFreqLock = false;
cCFOEstMean = [];
isFineFreqLock = false;
cCFOEst = [];
rxParams.fineFreqEstTemp = zeros(numFrames-rxParams.initialTimeSync,1);
headerDataDisplayCounter = 0;
streamFormat = "packetized";

Synchronization and Data Recovery

To synchronize the received data and recover the input bit stream, process the distorted DVB-S2 waveform samples one frame at a time by following these steps.

Apply DC offset compensation to remove any DC components.
Apply AGC to normalize the input signal amplitude.
Apply matched filtering, outputting at a rate of 2 samples per symbol.
Apply symbol timing synchronization using the Gardner timing error detector (TED) with an output generated at the symbol rate. The Gardner TED is not data-aided, so you can perform before carrier synchronization.
Apply frame synchronization to detect the start of frame and to identify the pilot positions.
Estimate and apply coarse frequency offset correction.
Estimate and apply fine frequency offset correction.
Estimate and compensate for residual carrier frequency and phase noise.
Decode the PL header and compute the transmission parameters.
Demodulate and decode the PL frames.
Perform CRC check on the BB header. If the check passes, recover the header parameters.
Regenerate the input stream of data or packets from BB frames.

while stIdx < length(rxIn)

    % Use one DVB-S2 PL frame for each iteration.
    endIdx = stIdx + rxParams.plFrameSize*rxParams.sps;

    % In the last iteration, consider all the remaining samples in the received
    % waveform.
    isLastFrame = endIdx > length(rxIn);
    endIdx(isLastFrame) = length(rxIn);
    rxData = rxIn(stIdx+1:endIdx);

    % After coarse frequency offset loop is converged, the FLL works with a
    % reduced loop bandwidth.
    if rxParams.frameCount < rxParams.initialTimeFreqSync
        isCoarseFreqLock = false;
    else
        isCoarseFreqLock = true;
    end

    % Retrieve the last frame samples.
    if isLastFrame
        resSymb = plFrameSize - length(rxParams.cfBuffer);
        resSampCnt = resSymb*rxParams.sps - length(rxData);
        if resSampCnt >= 0                                    % Inadequate number of samples to fill last frame
            syncIn = [rxData;zeros(resSampCnt,1)];
        else                                                  % Excess samples are available to fill last frame
            syncIn = rxData(1:resSymb*rxParams.sps);
        end
    else
        syncIn = rxData;
    end

    % Apply DC offset compensation, AGC, matched filtering, symbol timing synchronization, frame
    % synchronization, and coarse frequency offset compensation.
    syncIn = dcBlock(syncIn);
    syncIn = agc(syncIn);
    if rxParams.frameCount > 1
        [coarseFreqSyncOut,syncIndex,phEst] = timeFreqSync(syncIn,isCoarseFreqLock);
        coarseCFOEst = diff(phEst(1:sps:end)/(2*pi));
        if rxParams.frameCount <= rxParams.initialTimeSync
            symSyncOutLen = [symSyncOutLen;length(coarseFreqSyncOut)]; %#ok<*AGROW>
            if any(abs(diff(symSyncOutLen(1:rxParams.frameCount))) > 5)
                error(["Symbol timing synchronization failed. The loop will not " ...
                    "converge, resulting in frame recovery. Decrease the symbSyncLoopBW " ...
                    "parameter for proper loop convergence."]);
            end
        end
        if rxParams.frameCount > rxParams.initialTimeSync + 1
            cCFOEstMean = [cCFOEstMean;mean(coarseCFOEst)];
            cCFOEst = [cCFOEst;coarseCFOEst];
            if length(cCFOEstMean) > 2
                diffVal = diff(abs(cCFOEstMean));
                if all(diffVal(end-1:end) < 0.01) && ~isCoarseFreqLock
                    isCoarseFreqLock = true;
                    rxParams.initialTimeFreqSync = rxParams.frameCount;
                elseif isLastFrame && ~isCoarseFreqLock
                   fprintf("%s\n",["Coarse frequency error estimation failed. Try analyzing the cCFOEst " ...
                       "across frames and check carrier synchronization has converged. Try reducing the " ...
                       "carrSyncLoopBW parameters"]);
                end
            end
        end
        rxParams.syncIndex = syncIndex;
        % The PL frame start index lies somewhere in the middle of the frame being processed.
        % From fine frequency estimation, the processing happens as a PL frame.
        % A buffer stores the symbols required to fill one PL frame.
        if isLastFrame
            fineFreqIn = [rxParams.cfBuffer; coarseFreqSyncOut];
        elseif rxParams.frameCount > 1
            buffLen = rxParams.plFrameSize - length(rxParams.cfBuffer);
            if buffLen < length(coarseFreqSyncOut)
                fineFreqIn = [rxParams.cfBuffer; coarseFreqSyncOut(1:buffLen)];
            else
                fineFreqIn = [rxParams.cfBuffer; coarseFreqSyncOut];
            end
        end
        % Estimate the fine frequency error by using the HelperDVBS2FineFreqEst
        % helper function.
        % Add 1 to the conditional check because the buffer used to get one PL
        % frame introduces a delay of one to the loop count.
        if (rxParams.frameCount > rxParams.initialTimeFreqSync + 1) && ...
                ~isFineFreqLock
            rxParams.fineFreqCorrVal = HelperDVBS2FineFreqEst( ...
                fineFreqIn(rxParams.pilotInd),rxParams.numPilots, ...
                rxParams.refPilots,rxParams.fineFreqCorrVal);
            % Normalize the frequency estimate by the input symbol rate
            % freqEst = angle(R)/(pi*(N+1)), where N (18) is the number of elements
            % used to compute the mean of auto correlation (R) in
            % HelperDVBS2FineFreqEst.
            freqEst = angle(rxParams.fineFreqCorrVal)/(pi*(19));
            rxParams.fineFreqEstTemp(1:end-1) = rxParams.fineFreqEstTemp(2:end);
            rxParams.fineFreqEstTemp(end) = freqEst;
            numFreqEst = numFreqEst + 1;
            if numFreqEst >= 5
                cg = abs(diff(rxParams.fineFreqEstTemp));
                if all(cg(end-2:end) < 1e-4)
                    isFineFreqLock = true;
                    rxParams.totalSyncFrames = rxParams.frameCount;
                    fprintf("Estimated carrier frequency offset in Hz = %f\n",(coarseCFOEst(end) + freqEst).*Rsym);
                elseif isLastFrame && ~isFineFreqLock
                    fprintf("%s\n","Fine frequency error estimation failed. Try analyzing the pilot fields in the PL frame to debug the issue.")
                end
            end
        end
        if isFineFreqLock 
            % Normalize the frequency estimate by the input symbol rate
            % freqEst = angle(R)/(pi*(N+1)), where N (18) is the number of elements
            % used to compute the mean of auto correlation (R) in
            % HelperDVBS2FineFreqEst.
            freqEst = angle(rxParams.fineFreqCorrVal)/(pi*(19));

            % Generate the symbol indices using frameCount and plFrameSize.
            % Subtract 2 from the rxParams.frameCount because the buffer used to get one
            % PL frame introduces a delay of one to the count.
            ind = (rxParams.frameCount-2)*plFrameSize:(rxParams.frameCount-1)*plFrameSize-1;
            phErr = exp(-1j*2*pi*freqEst*ind);
            fineFreqOut = fineFreqIn.*phErr(:);

            % Estimate the phase error estimation by using the HelperDVBS2PhaseEst
            % helper function.
            [phEstRes,rxParams.prevPhaseEst] = HelperDVBS2PhaseEst( ...
                fineFreqOut,rxParams.refPilots,rxParams.prevPhaseEst,rxParams.pilotInd);

            % Compensate for the residual frequency and phase offset by using
            % the HelperDVBS2PhaseCompensate helper function.
            if rxParams.frameCount >= rxParams.totalSyncFrames + 2
                phaseCompOut = HelperDVBS2PhaseCompensate(rxParams.ffBuffer, ...
                    rxParams.pilotEst,rxParams.pilotInd,phEstRes(2));
            end

            rxParams.ffBuffer = fineFreqOut;
            rxParams.pilotEst = phEstRes;

            % Perform phase compensation on the data portion by
            % interpolating the phase estimates computed on consecutive pilot
            % blocks. The second phase estimate is not available for the data
            % portion after the last pilot block in the last frame. Therefore,
            % the slope of phase estimates computed on all pilot blocks in the
            % last frame is extrapolated and used to compensate for the phase
            % error on the final data portion.
            if isLastFrame
                pilotBlkLen = 36;                                               % Symbols
                pilotBlkFreq = 1476;                                            % Symbols
                avgSlope = mean(diff(phEstRes(2:end)));
                chunkLen = rxParams.plFrameSize - rxParams.pilotInd(end) + ...
                    rxParams.pilotInd(pilotBlkLen);
                estEndPh = phEstRes(end) + avgSlope*chunkLen/pilotBlkFreq;
                phaseCompOut1 = HelperDVBS2PhaseCompensate(rxParams.ffBuffer, ...
                    rxParams.pilotEst,rxParams.pilotInd,estEndPh);
            end
        end

        % Recover the input bit stream.
        if rxParams.frameCount >= rxParams.totalSyncFrames + 2
            isValid = true;
            if isLastFrame
                syncOut = [phaseCompOut; phaseCompOut1];
            else
                syncOut = phaseCompOut;
            end
        else
            isValid = false;
            syncOut = [];
        end

        % Update the buffers and counters.
        rxParams.cfBuffer = coarseFreqSyncOut(rxParams.syncIndex:end);

        if isValid  % Data valid signal

            % Decode the PL header by using the dvbsPLHeaderRecover
            % function
            syncOut = syncOut/sqrt(mean(abs(syncOut).^2));
            rxPLHeader = syncOut(1:90);
            phyParams = dvbsPLHeaderRecover(rxPLHeader,Mode="DVB-S2/S2X regular");
            M = phyParams.ModulationOrder;
            R = eval(phyParams.LDPCCodeIdentifier);
            fecFrame = phyParams.FECFrameLength;
            pilotStat = phyParams.HasPilots;
            xFECFrameLen = fecFrame/log2(M);
            % Validate the decoded PL header.
            if M ~= rxParams.modOrder || abs(R-rxParams.codeRate) > 1e-3 || ...
                    fecFrame ~= rxParams.cwLen || ~pilotStat
                fprintf("Pl frame number %d , %s\n",rxParams.frameCount, ...
                    "PL header decoding failed")
            else                                                                % Demodulation and decoding
                if ~headerDataDisplayCounter
                   fprintf("%s\n","Physical layer header detection summary")
                   detPLParams = generatePLParamsTable(M,R,fecFrame,pilotStat)
                   headerDataDisplayCounter = headerDataDisplayCounter + 1;
                end
                rxFrame = syncOut(1:plFrameSize);
                % Synchronized data constellation plot
                syncConst(rxFrame)
                % Estimate noise variance by using
                % HelperDVBS2NoiseVarEstimate helper function.
                nVar = HelperDVBS2NoiseVarEstimate(rxFrame,rxParams.pilotInd,...
                    rxParams.refPilots,false);
                snr_dB = 10*log10(1/nVar);
                fprintf("PL frame number = %d\n",rxParams.frameCount)
                fprintf("Estimated SNR in dB = %f\n",snr_dB)
                % Recover the input bit stream by using
                % dvbs2BitRecover function
                [decBitsTemp,isFrameLost,pktCRC]  = dvbs2BitRecover(rxFrame,nVar);
                decBits = decBitsTemp{:};
                if ~isLastFrame
                    pktsErr = pktsErr + numel(pktCRC{:}) - sum(pktCRC{:});
                    pktsRec = pktsRec + numel(pktCRC{:});
                end
                if ~isFrameLost
                    fprintf("%s\n","BB header decoding passed")
                    if isempty(pktCRC{1})
                        streamFormat = "continuous";
                    else
                        streamFormat = "packetized";
                    end
                else
                    fprintf("%s\n","BB header decoding failed")
                end
                % Compute the number of frames lost. Consider CRC failure of the baseband header
                % as a frame loss.
                numFramesLost = isFrameLost + numFramesLost;
                fprintf("Total number of frames lost = %1d\n",numFramesLost)
            end

        end
    end
    stIdx = endIdx;
    rxParams.frameCount = rxParams.frameCount + 1;
end

Estimated carrier frequency offset in Hz = 3013.949463

Physical layer header detection summary

detPLParams=1×4 table
    Modulation    Code Rate    FEC Frame    Pilot Status
    __________    _________    _________    ____________

     "32APSK"       "3/4"       "short"        "true"

PL frame number = 19

Estimated SNR in dB = 13.215241

BB header decoding passed

Total number of frames lost = 0

PL frame number = 20

Estimated SNR in dB = 14.539769

BB header decoding passed

Total number of frames lost = 0

Visualization and Error Logs

Plot the constellation of the synchronized data and compute PER.

% Error metrics display
% For GS and TS packetized streams
if strcmp(streamFormat,"packetized")
    if pktsRec == 0
        fprintf("All frames are lost. No packets are retrieved from BB frames.")
    else
        per = pktsErr/pktsRec;
        fprintf("PER: %1.2e\n",per)
    end
end

PER: 0.00e+00

Further Exploration

Transmit a DVB-S2 waveform by using the DVB-S2 Transmitter Using Software-Defined Radio example. You can then decode the waveform using this example. In the companion example, try changing the FECFrame and MODCOD, and observe the detected PL parameters decoded in this example.
For details on how to configure the synchronization parameters of the rxParams for other configurations, see the Further Exploration section of End-to-End DVB-S2 Simulation with RF Impairments and Corrections example.

SDR Troubleshooting

ADALM-PLUTO Radio Common Problems and Fixes (Communications Toolbox Support Package for Analog Devices ADALM-Pluto Radio)
USRP Radio Common Problems and Fixes

Supporting Files

The example uses these helper functions and data file:

HelperDVBS2TimeFreqSynchronizer.m: Perform matched filtering, symbol timing synchronization, frame synchronization, and coarse frequency estimation and correction
HelperDVBS2FrameSync.m: Perform frame synchronization and detect the start of frame
HelperDVBS2FineFreqEst.m: Estimate fine frequency offset
HelperDVBS2PhaseEst.m: Estimate carrier phase offset
HelperDVBS2PhaseCompensate.m: Perform carrier phase compensation
HelperDVBS2NoiseVarEstimate.m: Estimate noise variance of received data
capturedDVBS2Waveform.mat: DVB-S2 IQ data captured using DVB-S2 Transmitter Using Software-Defined Radio example and SDRs.

References

ETSI Standard EN 302 307-1 V1.4.1(2014-11). Digital Video Broadcasting (DVB); Second Generation Framing Structure, Channel Coding and Modulation Systems for Broadcasting, Interactive Services, News Gathering and other Broadband Satellite Applications (DVB-S2).
ETSI Standard TR 102 376-1 V1.2.1(2015-11). Digital Video Broadcasting (DVB); Implementation Guidelines for the Second Generation System for Broadcasting, Interactive Services, News Gathering and other Broadband Satellite Applications (DVB-S2).

Local Functions

function rxParams = getRxParams(fecFrame,modCod)
% Receiver parameters generation

[modOrder,codeRate,cwLen] = satcom.internal.dvbs.getS2PHYParams(modCod,fecFrame);

dataLen = cwLen/log2(modOrder);

% Pilot sequence and indices generation
slotLen = 90;
pilotBlkFreq = 16;                                                    % In slots
numPilotBlks = floor(dataLen/(slotLen*pilotBlkFreq));
if floor(dataLen/(slotLen*16)) == dataLen/(slotLen*pilotBlkFreq)
    numPilotBlks = numPilotBlks - 1;
end
pilotLen = numPilotBlks*36;                                           % one pilot block contains 36 pilot symbols
frameSize = dataLen + pilotLen + slotLen;
plScrambIntSeq = satcom.internal.dvbs.plScramblingIntegerSequence(0);
cMap = [1 1j -1 -1j].';
cSeq = cMap(plScrambIntSeq+1);
[~, pilotInd] = satcom.internal.dvbs.pilotBlock(numPilotBlks);

rxParams.plFrameSize = frameSize;
rxParams.xFecFrameSize = dataLen;
rxParams.modOrder = modOrder;
rxParams.codeRate = codeRate;
rxParams.cwLen = cwLen;
rxParams.frameCount = 1;
rxParams.numPilots = numPilotBlks;
rxParams.pilotInd = pilotInd + slotLen;
rxParams.refPilots = (1+1j)/sqrt(2).*cSeq(pilotInd);
rxParams.cfBuffer = [];
rxParams.ffBuffer = complex(zeros(frameSize, 1));
rxParams.pilotPhEst = zeros(numPilotBlks+1, 1);
[rxParams.prevPhaseEst, rxParams.fineFreqCorrVal] = deal(0);
rxParams.syncIndex = 1;
end
function tbl =  generatePLParamsTable(M,R,fecFrame,pilotStat)
modScheme = ["QPSK" "8PSK" "16APSK" "32APSK"];
Modulation = modScheme(log2(M)-1);
[n,d] = rat(R);
CodeRate = strcat(string(n),"/",string(d));
if fecFrame == 64800
    FECFrame = "normal";
else
    FECFrame = "short";
end
if pilotStat
    PilotStatus = "true";
else
    PilotStatus = "false";
end
tbl = table(Modulation,CodeRate,FECFrame,PilotStatus);
tbl = renamevars(tbl,["Modulation","CodeRate","FECFrame", "PilotStatus"],["Modulation","Code Rate","FEC Frame", "Pilot Status"]);
end

Related Examples

DVB-S2 Transmitter Using Software-Defined Radio