Bluetooth LE transmitter code in MATLAB

I am trying to use the Bluetooth LE in https://www.mathworks.com/help/comm/ug/bluetooth-low-energy-receiver.html. When I try to decode the data I saved in a .bb file created from the transmitter, I get an incorrect operation.

The code seems to run fine until I get to the part that calls:

[cfgLLAdv,pktCnt,crcCnt,remStartIdx] = helperBLEPhyBitRecover(rcvFilt,...

prbIdx,pktCnt,crcCnt,bleParam);

In the function, There is a function that determines the PDU length.

PDULenInBytes = comm.internal.utilities.bi2deRightMSB(PDULenField',2);

I am getting an incorrect value for PDULenInBytes. The value is way higher than the PDU's actual length. Once this happens the next lines of the code also fail because the size of the dewhitenedBits is less than the PDU size.

I have attached the output response waveform and the code for both transmitter and receiver.

%Transmitter Code:

%Transmission Frequency: 2.402 -

%RF Channels: 40

%Symbol Rate: 1Msym/s

%Modulation: GFSK

%Transmission Mode: LE1M i.e. Uncoded PHY with data rate of 1Mbps

%Preamble: 01010101 or 10101010 dependent on the first value of access

%address

%Access address: 32 bit field

%Payload maximum size is 2080 (includes every part of packet)

%%BLE Transmitter

clc;

phyMode = 'LE1M';

commSupportPackageCheck('BLUETOOTH'); %Check that MATLAB bluetooth is on system

symbolRate = 1e6;

channelBW = 2e6;

%Configure the advertising channel PDU

cfgLLAdv = bleLLAdvertisingChannelPDUConfig;

cfgLLAdv.PDUType = 'Advertising indication';

cfgLLAdv.AdvertisingData = '0123456789ABCDEF';

cfgLLAdv.AdvertiserAddress = '1234567890AB';

%Generate the message, pack into message bits

messageBits = bleLLAdvertisingChannelPDU(cfgLLAdv);

[status, value] = bleLLAdvertisingChannelPDUDecode(messageBits); %Loop exists here to go through octets of data entry

%For visualization purposes

numIter = 1;

sps = 8; % Samples per symbol

accessAddLen = 32;% Length of access address

accessAddHex = '8E89BED6'; % Access address value in hexadecimal

accessAddBin = de2bi(hex2dec(accessAddHex),accessAddLen)'; % Access address in binary

%Setting up visualization

% Create a spectrum analyzer object

specAn = dsp.SpectrumAnalyzer('SpectrumType','Power density');

specAn.SampleRate = symbolRate*sps;

% Create a time scope object

timeScope = timescope('SampleRate', symbolRate*sps,'TimeSpanSource','Auto',...

'ShowLegend',true);

rng default; %controlled repetiton

for numIdx = 1:numIter

channelIdx = randi([37 39],1,1);

%channelIdx = 37; % Channel index value in the range [0,39]

%Generate the waveform

txWaveform = bleWaveformGenerator(messageBits,...

'Mode', phyMode,...

'SamplesPerSymbol',sps,...

'ChannelIndex', channelIdx,...

'AccessAddress', accessAddBin);

% txWaveform = awgn(txWaveform,20,'measured');

% Initialize the parameters required for signal source

if channelIdx == 37

txCenterFrequency = 2.402e9;

elseif channelIdx == 38

txCenterFrequency = 2.426e9;

else

txCenterFrequency = 2.480e9;

end

txFrameLength = length(txWaveform);

txNumberOfFrames = 1; %1e4

txFrontEndSampleRate = symbolRate*sps;

% specAn.FrequencyOffset = channelBW*channelIdx;

specAn.Title = ['Spectrum of ',phyMode,' Waveform for Channel Index = ', num2str(channelIdx)];

channelIdx;

tic

while toc < 0.5 % To hold the spectrum for 0.5 seconds

specAn(txWaveform);

end

% Plot the generated waveform

timeScope.Title = ['BLE ',phyMode,' Waveform for Channel Index = ', num2str(channelIdx)];

timeScope(txWaveform);

end

sigSink = comm.BasebandFileWriter('CenterFrequency',txCenterFrequency,...

'Filename','bleCaptures.bb',...

'SampleRate',txFrontEndSampleRate);

sigSink(txWaveform); % Writing to a baseband file 'bleCaptures.bb'

%So basically it is a .bb because I can save the data

release(sigSink)

constDiagram = comm.ConstellationDiagram('SamplesPerSymbol',sps, ...

'SymbolsToDisplaySource','Property','SymbolsToDisplay',100);

constDiagram(txWaveform)

%% End

%Receive Code:

%%BLE Receiver

load 'Port ECG 1 [shielded 2020 10cm]-2020.09.30.17.01.31.716.MAT'

clc;

phyMode = 'LE1M';

bleParam = helperBLEReceiverConfig(phyMode);

bbFileName = 'bleCaptures.bb';

sigSrc = comm.BasebandFileReader(bbFileName);

sigSrcInfo = info(sigSrc);

sigSrc.SamplesPerFrame = sigSrcInfo.NumSamplesInData;

bbSampleRate = sigSrc.SampleRate;

bleParam.SamplesPerSymbol = bbSampleRate/bleParam.SymbolRate;

%View the received signal

spectrumScope = dsp.SpectrumAnalyzer( ...

'SampleRate', bbSampleRate,...

'SpectrumType', 'Power density', ...

'SpectralAverages', 10, ...

'YLimits', [-130 -10], ...

'Title', 'Received Baseband BLE Signal Spectrum', ...

'YLabel', 'Power spectral density');

dataCaptures = sigSrc();

% Show power spectral density of the received waveform

spectrumScope(dataCaptures);

agc = comm.AGC('MaxPowerGain',20,'DesiredOutputPower',2);

freqCompensator = comm.CoarseFrequencyCompensator('Modulation','OQPSK', ...

'SampleRate',bbSampleRate,...

'SamplesPerSymbol',2*bleParam.SamplesPerSymbol,...

'FrequencyResolution',100);

prbDet = comm.PreambleDetector(bleParam.RefSeq,'Detections','First');

length(dataCaptures)

bleParam.MinimumPacketLen;

pktCnt = 0;

crcCnt = 0;

displayFlag = true;%false; % true if the received data is to be printed

%while length(dataCaptures) > bleParam.MinimumPacketLen

% Consider two frames from the captured signal for each iteration

startIndex = 1;

endIndex = min(length(dataCaptures),2*bleParam.FrameLength);

rcvSig = dataCaptures(startIndex:endIndex);

rcvAGC = agc(rcvSig); % Perform AGC

rcvDCFree = rcvAGC - mean(rcvAGC); % Remove the DC offset

rcvFreqComp = freqCompensator(rcvDCFree); % Estimate and compensate for the carrier frequency offset

rcvFilt = conv(rcvFreqComp,bleParam.h,'same'); % Perform gaussian matched filtering

% Perform frame timing synchronization

[~, dtMt] = prbDet(rcvFilt);

release(prbDet)

prbDet.Threshold = max(dtMt);

prbIdx = prbDet(rcvFilt);

prbIdx;

% Extract message information

[cfgLLAdv,pktCnt,crcCnt,remStartIdx] = helperBLEPhyBitRecover(rcvFilt,...

prbIdx,pktCnt,crcCnt,bleParam);

% Remaining signal in the burst captures

dataCaptures = dataCaptures(1+remStartIdx:end);

% Display the decoded information

if displayFlag && ~isempty(cfgLLAdv)

disp('we are here')

fprintf('Advertising PDU Type: %s\n',cfgLLAdv.PDUType);

fprintf('Advertising Address: %s\n',cfgLLAdv.AdvertiserAddress);

end

% Release System objects

release(freqCompensator)

release(prbDet)

%end

% Release the signal source

release(sigSrc)

%%

[Akpabio Ekpewoh]

%Create a bluetooth LE transmitter

%RF Channels: 40
%Symbol Rate: 1Msym/s
%Modulation: GFSK
%Transmission Mode: LE1M i.e. Uncoded PHY with data rate of 1Mbps
%Preamble: 01010101 or 10101010 dependent on the first value of access
%address
%Access address: 32 bit field
%Payload maximum size is 2080 (includes every part of packet)

%%BLE Transmitter

clc;
phyMode = 'LE1M';
commSupportPackageCheck('BLUETOOTH'); %Check that MATLAB bluetooth is on system

symbolRate = 1e6;
channelBW = 2e6;

%Configure the advertising channel PDU
cfgLLAdv = bleLLAdvertisingChannelPDUConfig;
cfgLLAdv.PDUType         = 'Advertising indication';
cfgLLAdv.AdvertisingData = '0123456789ABCDEF';
cfgLLAdv.AdvertiserAddress = '1234567890AB';

%Generate the message, pack into message bits
messageBits = bleLLAdvertisingChannelPDU(cfgLLAdv);

[status, value] = bleLLAdvertisingChannelPDUDecode(messageBits); %Loop exists here to go through octets of data entry
%For visualization purposes
numIter = 1;
sps = 8; % Samples per symbol
accessAddLen = 32;% Length of access address
accessAddHex = '8E89BED6';  % Access address value in hexadecimal
accessAddBin = de2bi(hex2dec(accessAddHex),accessAddLen)'; % Access address in binary

%Setting up visualization
% Create a spectrum analyzer object
specAn = dsp.SpectrumAnalyzer('SpectrumType','Power density');
specAn.SampleRate = symbolRate*sps;

% Create a time scope object
timeScope = timescope('SampleRate', symbolRate*sps,'TimeSpanSource','Auto',...
     'ShowLegend',true);

rng default; %controlled repetiton
for numIdx = 1:numIter
    channelIdx = randi([37 39],1,1);
    %channelIdx = 37;  % Channel index value in the range [0,39]
    %Generate the waveform
    txWaveform = bleWaveformGenerator(messageBits,...
        'Mode',            phyMode,...
        'SamplesPerSymbol',sps,...
        'ChannelIndex',    channelIdx,...
        'AccessAddress',   accessAddBin);
  %  txWaveform = awgn(txWaveform,20,'measured');
% Initialize the parameters required for signal source
    if channelIdx == 37
    txCenterFrequency       = 2.402e9;
    elseif channelIdx == 38
    txCenterFrequency       = 2.426e9;
    else
    txCenterFrequency       = 2.480e9;
    end

    txFrameLength           = length(txWaveform);
    txNumberOfFrames        = 1; %1e4
    txFrontEndSampleRate    = symbolRate*sps;
    
%    specAn.FrequencyOffset = channelBW*channelIdx;
    specAn.Title = ['Spectrum of ',phyMode,' Waveform for Channel Index = ', num2str(channelIdx)];

    channelIdx;
    tic
    while toc < 0.5 % To hold the spectrum for 0.5 seconds
        specAn(txWaveform);
    end

    % Plot the generated waveform
    timeScope.Title = ['BLE ',phyMode,' Waveform for Channel Index = ', num2str(channelIdx)];
    timeScope(txWaveform);   
end
sigSink = comm.BasebandFileWriter('CenterFrequency',txCenterFrequency,...
        'Filename','bleCaptures.bb',...
        'SampleRate',txFrontEndSampleRate);


sigSink(txWaveform); % Writing to a baseband file 'bleCaptures.bb'
%So basically it is a .bb because I can save the data
release(sigSink)

constDiagram = comm.ConstellationDiagram('SamplesPerSymbol',sps, ...
    'SymbolsToDisplaySource','Property','SymbolsToDisplay',100);
constDiagram(txWaveform)

%% End



%Receiver
%%BLE Receiver
load 'Port ECG 1 [shielded 2020 10cm]-2020.09.30.17.01.31.716.MAT'
clc;
phyMode = 'LE1M';
bleParam = helperBLEReceiverConfig(phyMode);

bbFileName = 'bleCaptures.bb';

sigSrc = comm.BasebandFileReader(bbFileName);
sigSrcInfo = info(sigSrc);
sigSrc.SamplesPerFrame = sigSrcInfo.NumSamplesInData;
bbSampleRate = sigSrc.SampleRate;
bleParam.SamplesPerSymbol = bbSampleRate/bleParam.SymbolRate;

%View the received signal
spectrumScope = dsp.SpectrumAnalyzer( ...
    'SampleRate',       bbSampleRate,...
    'SpectrumType',     'Power density', ...
    'SpectralAverages', 10, ...
    'YLimits',          [-130 -10], ...
    'Title',            'Received Baseband BLE Signal Spectrum', ...
    'YLabel',           'Power spectral density');

dataCaptures = sigSrc();
% Show power spectral density of the received waveform
spectrumScope(dataCaptures);

agc = comm.AGC('MaxPowerGain',20,'DesiredOutputPower',2);

freqCompensator = comm.CoarseFrequencyCompensator('Modulation','OQPSK', ...
    'SampleRate',bbSampleRate,...
    'SamplesPerSymbol',2*bleParam.SamplesPerSymbol,...
    'FrequencyResolution',100);


prbDet = comm.PreambleDetector(bleParam.RefSeq,'Detections','First');
length(dataCaptures)
bleParam.MinimumPacketLen;

pktCnt = 0;
crcCnt = 0;
displayFlag = true;%false; % true if the received data is to be printed
%while length(dataCaptures) > bleParam.MinimumPacketLen

    % Consider two frames from the captured signal for each iteration

    startIndex = 1;
    endIndex = min(length(dataCaptures),2*bleParam.FrameLength);
    rcvSig = dataCaptures(startIndex:endIndex);

    rcvAGC = agc(rcvSig); % Perform AGC
    rcvDCFree = rcvAGC - mean(rcvAGC); % Remove the DC offset
    rcvFreqComp = freqCompensator(rcvDCFree); % Estimate and compensate for the carrier frequency offset
    rcvFilt = conv(rcvFreqComp,bleParam.h,'same'); % Perform gaussian matched filtering

    % Perform frame timing synchronization
    [~, dtMt] = prbDet(rcvFilt);
    release(prbDet)
    prbDet.Threshold = max(dtMt);
    prbIdx = prbDet(rcvFilt);
    
    prbIdx;
    % Extract message information
    [cfgLLAdv,pktCnt,crcCnt,remStartIdx] = helperBLEPhyBitRecover(rcvFilt,...
        prbIdx,pktCnt,crcCnt,bleParam);

    % Remaining signal in the burst captures
    dataCaptures = dataCaptures(1+remStartIdx:end);
   
    % Display the decoded information
    if displayFlag && ~isempty(cfgLLAdv)
        disp('we are here')
        fprintf('Advertising PDU Type: %s\n',cfgLLAdv.PDUType);
        fprintf('Advertising Address: %s\n',cfgLLAdv.AdvertiserAddress);
    end

    % Release System objects
    release(freqCompensator)
    release(prbDet)
%end

% Release the signal source
release(sigSrc)
%%