Bluetooth LE Waveform Generation and Transmission Using SDR

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

% Generate an advertising channel PDU
messageBits = bleLLAdvertisingChannelPDU(cfgLLAdv);

phyMode = 'LE1M'; % Select one mode from the set {'LE1M','LE2M','LE500K','LE125K'}
sps = 8;          % Samples per symbol
channelIndex = 37;  % Channel index value in the range [0,39]
accessAddressLen = 32;% Length of access address
accessAddressHex = '8E89BED6';  % Access address value in hexadecimal
accessAddressBin = int2bit(hex2dec(accessAddressHex),accessAddressLen,false); % Access address in binary

% Symbol rate based on |'Mode'|
symbolRate = 1e6;
if strcmp(phyMode,'LE2M')
    symbolRate = 2e6;
end

% Generate Bluetooth LE waveform
txWaveform = bleWaveformGenerator(messageBits,...
    'Mode',            phyMode,...
    'SamplesPerSymbol',sps,...
    'ChannelIndex',    channelIndex,...
    'AccessAddress',   accessAddressBin);

% Set up spectrum viewer
spectrumScope = spectrumAnalyzer('Method','welch', ...
    'SampleRate',       symbolRate*sps,...
    'SpectrumType',     'Power density', ...
    'SpectralAverages', 10, ...
    'YLimits',          [-130 0], ...
    'Title',            'Baseband Bluetooth LE Signal Spectrum', ...
    'YLabel',           'Power spectral density');

% Show power spectral density of the Bluetooth LE signal
spectrumScope(txWaveform);

% Initialize the parameters required for signal source
txCenterFrequency       = 2.402e9;  % Varies based on channel index value
txFrameLength           = length(txWaveform);
txNumberOfFrames        = 1e4;
txFrontEndSampleRate    = symbolRate*sps;

% The default signal source is 'File'
signalSink = 'File';

if strcmp(signalSink,'File')

    sigSink = comm.BasebandFileWriter('CenterFrequency',txCenterFrequency,...
        'Filename','bleCaptures.bb',...
        'SampleRate',txFrontEndSampleRate);
    sigSink(txWaveform); % Writing to a baseband file 'bleCaptures.bb'

elseif strcmp(signalSink,'ADALM-PLUTO')

    % First check if the HSP exists
    if isempty(which('plutoradio.internal.getRootDir'))
		link = sprintf('<a href="https://www.mathworks.com/hardware-support/adalm-pluto-radio.html"> ADALM-PLUTO Radio Support From Communications Toolbox</a>');
        error('Unable to find Communications Toolbox Support Package for ADALM-PLUTO Radio. To install the support package, visit %s.', link);
    end
    connectedRadios = findPlutoRadio; % Discover ADALM-PLUTO radio(s) connected to your computer
    radioID = connectedRadios(1).RadioID;
    sigSink = sdrtx( 'Pluto',...
        'RadioID',           radioID,...
        'CenterFrequency',   txCenterFrequency,...
        'Gain',              0,...
        'SamplesPerFrame',   txFrameLength,...
        'BasebandSampleRate',txFrontEndSampleRate);
    % The transfer of baseband data to the SDR hardware is enclosed in a
    % try/catch block. This means that if an error occurs during the
    % transmission, the hardware resources used by the SDR System
    % object(TM) are released.
    currentFrame = 1;
    try
        while currentFrame <= txNumberOfFrames
            % Data transmission
            sigSink(txWaveform);
            % Update the counter
            currentFrame = currentFrame + 1;
        end
    catch ME
        release(sigSink);
        rethrow(ME)
    end
else
    error('Invalid signal sink. Valid entries are File and ADALM-PLUTO.');
end

% Release the signal sink
release(sigSink)