function [preamble,c1,c2] = generatePreamble(WaveformPara,Power)

    N = WaveformPara.N_FFT;
    L = WaveformPara.CP_Len;
    pnSequence = comm.PNSequence('Polynomial',[8 6 5 4 0], ...
        'SamplesPerFrame',N,'InitialConditions',[0 0 0 0 0 0 0 1]);
    pnSeq1 = pnSequence();

    Modulator = comm.QPSKModulator;

    dataInMatrix1 = reshape(pnSeq1,N/2,2);
    dataSymbolsIn1 = bi2de(dataInMatrix1);   

    pnSeq1 = Modulator(dataSymbolsIn1);

    c1 = sqrt(2)*kron(pnSeq1,[1,0]');

    pnSequence = comm.PNSequence('Polynomial',[8 6 5 4 0], ...
        'SamplesPerFrame',N,'InitialConditions',[0 1 0 0 0 0 0 1]);
    pnSeq2 = pnSequence();                
    dataInMatrix2 = reshape(pnSeq2,N/2,2);
    dataSymbolsIn2 = bi2de(dataInMatrix2); 

    pnSeq2 = Modulator(dataSymbolsIn2);

    pnSequence = comm.PNSequence('Polynomial',[8 6 5 4 0], ...
        'SamplesPerFrame',N,'InitialConditions',[1 1 0 0 1 0 0 1]);
    pnSeq3 = pnSequence();
    dataInMatrix3 = reshape(pnSeq3,N/2,2);
    dataSymbolsIn3 = bi2de(dataInMatrix3); 

    pnSeq3 = Modulator(dataSymbolsIn3);

    c2 = zeros(N,1); 
    c2(1:2:N-1) = pnSeq2;
    c2(2:2:N) = pnSeq3;

    ofdmSymbol = ifft(c1,N)*sqrt(N);
    cp = ofdmSymbol(length(ofdmSymbol)-L+1:end);
    trainingSym1 = [cp;ofdmSymbol];
    
    ofdmSymbol = ifft(c2,N)*sqrt(N);
    cp = ofdmSymbol(length(ofdmSymbol)-L+1:end);
    trainingSym2 = [cp;ofdmSymbol];

    preamble = sqrt(Power)/sqrt(2)*([trainingSym1;trainingSym2]);
end