/*
 * Copyright (c) 2010 The Boeing Company
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Gary Pei <guangyu.pei@boeing.com>
 */

#ifndef NIST_ERROR_RATE_MODEL_H
#define NIST_ERROR_RATE_MODEL_H

#include "error-rate-model.h"
#include "wifi-mode.h"

namespace ns3
{

/**
 * \ingroup wifi
 *
 * A model for the error rate for different modulations.  For OFDM modulation,
 * the model description and validation can be found in
 * http://www.nsnam.org/~pei/80211ofdm.pdf.  For DSSS modulations (802.11b),
 * the model uses the DsssErrorRateModel.
 */
class NistErrorRateModel : public ErrorRateModel
{
  public:
    /**
     * \brief Get the type ID.
     * \return the object TypeId
     */
    static TypeId GetTypeId();

    NistErrorRateModel();

  private:
    double DoGetChunkSuccessRate(WifiMode mode,
                                 const WifiTxVector& txVector,
                                 double snr,
                                 uint64_t nbits,
                                 uint8_t numRxAntennas,
                                 WifiPpduField field,
                                 uint16_t staId) const override;
    /**
     * Return the bValue such that coding rate = bValue / (bValue + 1).
     *
     * \param codeRate the coding rate
     *
     * \return the bValue such that coding rate = bValue / (bValue + 1)
     */
    uint8_t GetBValue(WifiCodeRate codeRate) const;
    /**
     * Return the coded BER for the given p and b.
     *
     * \param p the SNR ratio (in linear scale)
     * \param bValue such that coding rate = bValue / (bValue + 1)
     *
     * \return the coded BER
     */
    double CalculatePe(double p, uint8_t bValue) const;
    /**
     * Return BER of BPSK at the given SNR.
     *
     * \param snr SNR ratio (in linear scale)
     *
     * \return BER of BPSK at the given SNR
     */
    double GetBpskBer(double snr) const;
    /**
     * Return BER of QPSK at the given SNR.
     *
     * \param snr SNR ratio (in linear scale)
     *
     * \return BER of QPSK at the given SNR
     */
    double GetQpskBer(double snr) const;
    /**
     * Return BER of QAM for a given constellation size at the given SNR.
     *
     * \param constellationSize the constellation size (M)
     * \param snr SNR ratio (in linear scale)
     * \return BER of QAM for a given constellation size at the given SNR
     */
    double GetQamBer(uint16_t constellationSize, double snr) const;
    /**
     * Return BER of BPSK at the given SNR after applying FEC.
     *
     * \param snr SNR ratio (in linear scale)
     * \param nbits the number of bits in the chunk
     * \param bValue the bValue such that coding rate = bValue / (bValue + 1)
     *
     * \return BER of BPSK at the given SNR after applying FEC
     */
    double GetFecBpskBer(double snr, uint64_t nbits, uint8_t bValue) const;
    /**
     * Return BER of QPSK at the given SNR after applying FEC.
     *
     * \param snr SNR ratio (in linear scale)
     * \param nbits the number of bits in the chunk
     * \param bValue the bValue such that coding rate = bValue / (bValue + 1)
     *
     * \return BER of QPSK at the given SNR after applying FEC
     */
    double GetFecQpskBer(double snr, uint64_t nbits, uint8_t bValue) const;
    /**
     * Return BER of QAM for a given constellation size at the given SNR after applying FEC.
     *
     * \param constellationSize the constellation size (M)
     * \param snr SNR ratio (in linear scale)
     * \param nbits the number of bits in the chunk
     * \param bValue the bValue such that coding rate = bValue / (bValue + 1)
     *
     * \return BER of QAM for a given constellation size at the given SNR after applying FEC
     */
    double GetFecQamBer(uint16_t constellationSize,
                        double snr,
                        uint64_t nbits,
                        uint8_t bValue) const;
};

} // namespace ns3

#endif /* NIST_ERROR_RATE_MODEL_H */
