frame_builder.cpp

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#include <arpa/inet.h>
#include <boost/crc.hpp>

#include "frame_builder.h"
#include "interleaver.h"
#include "qam.h"
#include "ppdu.h"
#include "symbol_mapper.h"
#include "fft.h"
#include "preamble.h"
#include "rates.h"
#include "viterbi.h"
#include "parity.h"
#include "modulator.h"
#include "puncturer.h"


#define preamble_length 256 

namespace fun
{
    frame_builder::frame_builder() :
        m_ifft(64)
    {
    }

    std::vector<std::complex<double> > frame_builder::build_frame(std::vector<unsigned char> payload, Rate rate)
    {
        //Append header, scramble, code, interleave, & modulate
        ppdu ppdu_frame(payload, rate);        
        std::vector<std::complex<double> > samples = ppdu_frame.encode();

        // Map the subcarriers and insert pilots
        symbol_mapper mapper = symbol_mapper();
        std::vector<std::complex<double> > mapped = mapper.map(samples);

        // Perform the IFFT
        m_ifft.inverse(mapped);

        // Add the cyclic prefixes
        std::vector<std::complex<double> > prefixed(mapped.size() * 80 / 64);
        for(int x = 0; x < mapped.size() / 64; x++)
        {
            memcpy(&prefixed[x*80], &mapped[x*64+48], 16*sizeof(std::complex<double>));
            memcpy(&prefixed[x*80+16], &mapped[x*64], 64*sizeof(std::complex<double>));
        }

        // Prepend the preamble
        std::vector<std::complex<double> > frame(prefixed.size() + 320);

        memcpy(&frame[0], &PREAMBLE_SAMPLES[0], 320 * sizeof(std::complex<double>));
        memcpy(&frame[320], &prefixed[0], prefixed.size() * sizeof(std::complex<double>));

        // Return the samples
        return frame;
    }
}