/*
 * Copyright (c) 2009 CTTC
 * Copyright (c) 2017 Orange Labs
 *
 * 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
 *
 * Authors: Nicola Baldo <nbaldo@cttc.es>
 *          Rediet <getachew.redieteab@orange.com>
 */

#ifndef WIFI_SPECTRUM_VALUE_HELPER_H
#define WIFI_SPECTRUM_VALUE_HELPER_H

#include <ns3/spectrum-value.h>

namespace ns3
{

/**
 * typedef for a pair of start and stop sub-band indexes
 */
typedef std::pair<uint32_t, uint32_t> WifiSpectrumBand;

/**
 * \ingroup spectrum
 *
 *  This class defines all functions to create a spectrum model for
 *  Wi-Fi based on a a spectral model aligned with an OFDM subcarrier
 *  spacing of 312.5 KHz (model also reused for DSSS modulations)
 */
class WifiSpectrumValueHelper
{
  public:
    /**
     * Destructor
     */
    virtual ~WifiSpectrumValueHelper();

    /**
     * Return a SpectrumModel instance corresponding to the center frequency
     * and channel width.  The spectrum model spans the channel width
     * +/- the guard bands (i.e. the model will span (channelWidth +
     * 2 * guardBandwidth) MHz of bandwidth).
     *
     * \param centerFrequency center frequency (MHz)
     * \param channelWidth channel width (MHz)
     * \param bandBandwidth width of each band (Hz)
     * \param guardBandwidth width of the guard band (MHz)
     *
     * \return the static SpectrumModel instance corresponding to the
     * given carrier frequency and channel width configuration.
     */
    static Ptr<SpectrumModel> GetSpectrumModel(uint32_t centerFrequency,
                                               uint16_t channelWidth,
                                               uint32_t bandBandwidth,
                                               uint16_t guardBandwidth);

    /**
     * Create a transmit power spectral density corresponding to DSSS
     *
     * The center frequency typically corresponds to 802.11b channel
     * center frequencies but is not restricted to those frequencies.
     *
     * \note There is no channel width parameter; this method assumes 22 MHz
     *
     * \param centerFrequency center frequency (MHz)
     * \param txPowerW  transmit power (W) to allocate
     * \param guardBandwidth width of the guard band (MHz)
     * \returns a pointer to a newly allocated SpectrumValue representing the DSSS Transmit Power
     * Spectral Density in W/Hz
     */
    static Ptr<SpectrumValue> CreateDsssTxPowerSpectralDensity(uint32_t centerFrequency,
                                                               double txPowerW,
                                                               uint16_t guardBandwidth);

    /**
     * Create a transmit power spectral density corresponding to OFDM
     * (802.11a/g).  Channel width may vary between 20, 10, and 5 MHz.
     * Guard bandwidth also typically varies with channel width.
     *
     * \param centerFrequency center frequency (MHz)
     * \param channelWidth channel width (MHz)
     * \param txPowerW  transmit power (W) to allocate
     * \param guardBandwidth width of the guard band (MHz)
     * \param minInnerBandDbr the minimum relative power in the inner band (in dBr)
     * \param minOuterbandDbr the minimum relative power in the outer band (in dBr)
     * \param lowestPointDbr maximum relative power of the outermost subcarriers of the guard band
     * (in dBr)
     * \return a pointer to a newly allocated SpectrumValue representing the OFDM Transmit Power
     * Spectral Density in W/Hz for each Band
     */
    static Ptr<SpectrumValue> CreateOfdmTxPowerSpectralDensity(uint32_t centerFrequency,
                                                               uint16_t channelWidth,
                                                               double txPowerW,
                                                               uint16_t guardBandwidth,
                                                               double minInnerBandDbr = -20,
                                                               double minOuterbandDbr = -28,
                                                               double lowestPointDbr = -40);

    /**
     * Create a transmit power spectral density corresponding to OFDM duplicated over multiple 20
     * MHz subchannels. Channel width may vary between 20, 40, 80, and 160 MHz.
     *
     * \param centerFrequency center frequency (MHz)
     * \param channelWidth channel width (MHz)
     * \param txPowerW  transmit power (W) to allocate
     * \param guardBandwidth width of the guard band (MHz)
     * \param minInnerBandDbr the minimum relative power in the inner band (in dBr)
     * \param minOuterbandDbr the minimum relative power in the outer band (in dBr)
     * \param lowestPointDbr maximum relative power of the outermost subcarriers of the guard band
     * (in dBr)
     * \param puncturedSubchannels bitmap indicating whether a 20 MHz subchannel is punctured or not
     * \return a pointer to a newly allocated SpectrumValue representing the duplicated 20 MHz OFDM
     * Transmit Power Spectral Density in W/Hz for each Band
     */
    static Ptr<SpectrumValue> CreateDuplicated20MhzTxPowerSpectralDensity(
        uint32_t centerFrequency,
        uint16_t channelWidth,
        double txPowerW,
        uint16_t guardBandwidth,
        double minInnerBandDbr = -20,
        double minOuterbandDbr = -28,
        double lowestPointDbr = -40,
        const std::vector<bool>& puncturedSubchannels = std::vector<bool>{});

    /**
     * Create a transmit power spectral density corresponding to OFDM
     * High Throughput (HT) (802.11n/ac).  Channel width may vary between
     * 20, 40, 80, and 160 MHz.
     *
     * \param centerFrequency center frequency (MHz)
     * \param channelWidth channel width (MHz)
     * \param txPowerW  transmit power (W) to allocate
     * \param guardBandwidth width of the guard band (MHz)
     * \param minInnerBandDbr the minimum relative power in the inner band (in dBr)
     * \param minOuterbandDbr the minimum relative power in the outer band (in dBr)
     * \param lowestPointDbr maximum relative power of the outermost subcarriers of the guard band
     * (in dBr)
     * \return a pointer to a newly allocated SpectrumValue representing the HT OFDM Transmit Power
     * Spectral Density in W/Hz for each Band
     */
    static Ptr<SpectrumValue> CreateHtOfdmTxPowerSpectralDensity(uint32_t centerFrequency,
                                                                 uint16_t channelWidth,
                                                                 double txPowerW,
                                                                 uint16_t guardBandwidth,
                                                                 double minInnerBandDbr = -20,
                                                                 double minOuterbandDbr = -28,
                                                                 double lowestPointDbr = -40);

    /**
     * Create a transmit power spectral density corresponding to OFDM
     * High Efficiency (HE) (802.11ax).  Channel width may vary between
     * 20, 40, 80, and 160 MHz.
     *
     * \param centerFrequency center frequency (MHz)
     * \param channelWidth channel width (MHz)
     * \param txPowerW  transmit power (W) to allocate
     * \param guardBandwidth width of the guard band (MHz)
     * \param minInnerBandDbr the minimum relative power in the inner band (in dBr)
     * \param minOuterbandDbr the minimum relative power in the outer band (in dBr)
     * \param lowestPointDbr maximum relative power of the outermost subcarriers of the guard band
     * (in dBr)
     * \param puncturedSubchannels bitmap indicating whether a 20 MHz subchannel is punctured or not
     * \return a pointer to a newly allocated SpectrumValue representing the HE OFDM Transmit Power
     * Spectral Density in W/Hz for each Band
     */
    static Ptr<SpectrumValue> CreateHeOfdmTxPowerSpectralDensity(
        uint32_t centerFrequency,
        uint16_t channelWidth,
        double txPowerW,
        uint16_t guardBandwidth,
        double minInnerBandDbr = -20,
        double minOuterbandDbr = -28,
        double lowestPointDbr = -40,
        const std::vector<bool>& puncturedSubchannels = std::vector<bool>{});

    /**
     * Create a transmit power spectral density corresponding to the OFDMA part
     * of HE TB PPDUs for a given RU.
     * An ideal (i.e. rectangular) spectral mask is considered for the time being.
     *
     * \param centerFrequency center frequency (MHz)
     * \param channelWidth channel width (MHz)
     * \param txPowerW  transmit power (W) to allocate
     * \param guardBandwidth width of the guard band (MHz)
     * \param ru the RU band used by the STA
     * \return a pointer to a newly allocated SpectrumValue representing the HE OFDM Transmit Power
     * Spectral Density on the RU used by the STA in W/Hz for each Band
     */
    static Ptr<SpectrumValue> CreateHeMuOfdmTxPowerSpectralDensity(uint32_t centerFrequency,
                                                                   uint16_t channelWidth,
                                                                   double txPowerW,
                                                                   uint16_t guardBandwidth,
                                                                   WifiSpectrumBand ru);

    /**
     * Create a power spectral density corresponding to the noise
     *
     * \param centerFrequency center frequency (MHz)
     * \param channelWidth channel width (MHz)
     * \param bandBandwidth width of each band (Hz)
     * \param noiseFigure the noise figure in dB w.r.t. a reference temperature of 290K
     * \param guardBandwidth width of the guard band (MHz)
     * \return a pointer to a newly allocated SpectrumValue representing the noise Power Spectral
     * Density in W/Hz for each Band
     */
    static Ptr<SpectrumValue> CreateNoisePowerSpectralDensity(uint32_t centerFrequency,
                                                              uint16_t channelWidth,
                                                              uint32_t bandBandwidth,
                                                              double noiseFigure,
                                                              uint16_t guardBandwidth);

    /**
     * Create a thermal noise power spectral density
     *
     * \param noiseFigure the noise figure
     * \param spectrumModel the spectrum model
     * \return a pointer to a newly allocated SpectrumValue representing the noise Power Spectral
     * Density in W/Hz corresponding to thermal noise, for each Band
     */
    static Ptr<SpectrumValue> CreateNoisePowerSpectralDensity(double noiseFigure,
                                                              Ptr<SpectrumModel> spectrumModel);

    /**
     * Create a spectral density corresponding to the RF filter
     *
     * \param centerFrequency the center frequency (MHz)
     * \param totalChannelWidth the total channel width (MHz)
     * \param bandBandwidth the width of each band (MHz)
     * \param guardBandwidth the width of the guard band (MHz)
     * \param band the pair of start and stop indexes that defines the band to be filtered
     *
     * \return a pointer to a SpectrumValue representing the RF filter applied
     * to an received power spectral density
     */
    static Ptr<SpectrumValue> CreateRfFilter(uint32_t centerFrequency,
                                             uint16_t totalChannelWidth,
                                             uint32_t bandBandwidth,
                                             uint16_t guardBandwidth,
                                             WifiSpectrumBand band);

    /**
     * Create a transmit power spectral density corresponding to OFDM
     * transmit spectrum mask requirements for 11a/11g/11n/11ac/11ax
     * Channel width may vary between 5, 10, 20, 40, 80, and 160 MHz.
     * The default (standard) values are illustrated below.
     *
     *   [ guard band  ][    channel width     ][  guard band ]
     *                   __________   __________                  _ 0 dBr
     *                  /          | |          \
     *                 /           |_|           \                _ -20 dBr
     *             . '                             ' .
     *         . '                                     ' .        _ -28 dBr
     *       .'                                           '.
     *     .'                                               '.
     *   .'                                                   '.  _ lowest point
     *
     *   |-----|                                         |-----|  outerBand left/right
     *         |------|                           |-- ---|        middle band left/right
     *                |-|                       |-|               inner band left/right
     *                  |-----------------------|                 allocated sub-bands
     *   |-----------------------------------------------------|  mask band
     *
     * Please take note that, since guard tones are within the allocated band
     * while not being ideally allocated any power, the inner band had to be
     * shifted inwards and a flat junction band (at -20 dBr) had to be added
     * between the inner and the middle bands.
     *
     * \param c spectrumValue to allocate according to transmit power spectral density mask (in W/Hz
     * for each band)
     * \param allocatedSubBands vector of start and stop subcarrier indexes of the allocated sub
     * bands
     * \param maskBand start and stop subcarrier indexes of transmit mask (in case signal doesn't
     * cover whole SpectrumModel)
     * \param txPowerPerBandW power allocated to each subcarrier in the allocated sub bands
     * \param nGuardBands size (in number of subcarriers) of the guard band (left and right)
     * \param innerSlopeWidth size (in number of subcarriers) of the inner band (i.e. slope going
     * from 0 dBr to -20 dBr in the figure above)
     * \param minInnerBandDbr the minimum relative power in the inner band (i.e., -20 dBr in the
     * figure above)
     * \param minOuterbandDbr the minimum relative power in the outer band (i.e., -28 dBr in the
     * figure above)
     * \param lowestPointDbr maximum relative power of the outermost subcarriers of the guard band
     * (in dBr)
     * \param puncturedSubBands vector of start and stop subcarrier indexes of the punctured sub
     * bands
     * \param puncturedSlopeWidth size (in number of subcarriers) of the punctured band slope
     */
    static void CreateSpectrumMaskForOfdm(
        Ptr<SpectrumValue> c,
        const std::vector<WifiSpectrumBand>& allocatedSubBands,
        WifiSpectrumBand maskBand,
        double txPowerPerBandW,
        uint32_t nGuardBands,
        uint32_t innerSlopeWidth,
        double minInnerBandDbr,
        double minOuterbandDbr,
        double lowestPointDbr,
        const std::vector<WifiSpectrumBand>& puncturedSubBands = std::vector<WifiSpectrumBand>{},
        uint32_t puncturedSlopeWidth = 0);

    /**
     * Normalize the transmit spectrum mask generated by CreateSpectrumMaskForOfdm
     * so that the total transmitted power corresponds to the input value.
     *
     * \param c spectrumValue to normalize (in W/Hz for each band)
     * \param txPowerW total transmit power (W) to allocate
     */
    static void NormalizeSpectrumMask(Ptr<SpectrumValue> c, double txPowerW);

    /**
     * Convert from dBm to Watts.
     * Taken from wifi-utils since the original method couldn't be called from here
     * due to resulting circular dependencies of spectrum and wifi modules.
     *
     * \param dbm the power in dBm
     *
     * \return the equivalent Watts for the given dBm
     */
    static double DbmToW(double dbm);

    /**
     * Calculate the power of the specified band composed of uniformly-sized sub-bands.
     *
     * \param psd received Power Spectral Density in W/Hz
     * \param band a pair of start and stop indexes that defines the band
     *
     * \return band power in W
     */
    static double GetBandPowerW(Ptr<SpectrumValue> psd, const WifiSpectrumBand& band);
};

/**
 * \ingroup spectrum
 *
 * Implements Wifi SpectrumValue for the 2.4 GHz ISM band only, with a
 * 5 MHz spectrum resolution.
 *
 */
class WifiSpectrumValue5MhzFactory
{
  public:
    /**
     * Destructor
     */
    virtual ~WifiSpectrumValue5MhzFactory();
    /**
     * Creates a SpectrumValue instance with a constant value for all frequencies
     *
     * @param psd the constant value
     *
     * @return a Ptr to a newly created SpectrumValue
     */
    virtual Ptr<SpectrumValue> CreateConstant(double psd);
    /**
     * Creates a SpectrumValue instance that represents the TX Power Spectral
     * Density  of a wifi device corresponding to the provided parameters
     *
     * Since the spectrum model has a resolution of 5 MHz, we model
     * the transmitted signal with a constant density over a 20MHz
     * bandwidth centered on the center frequency of the channel. The
     * transmission power outside the transmission power density is
     * calculated considering the transmit spectrum mask, see IEEE
     * Std. 802.11-2007, Annex I.  The two bands just outside of the main
     * 20 MHz are allocated power at -28 dB down from the center 20 MHz,
     * and the two bands outside of this are allocated power at -40 dB down
     * (with a total bandwidth of 60 MHz containing non-zero power allocation).
     *
     * @param txPower the total TX power in W
     * @param channel the number of the channel (1 <= channel <= 13)
     *
     * @return a Ptr to a newly created SpectrumValue
     */
    virtual Ptr<SpectrumValue> CreateTxPowerSpectralDensity(double txPower, uint8_t channel);
    /**
     * Creates a SpectrumValue instance which
     * represents the frequency response of the RF filter which is used
     * by a wifi device to receive signals when tuned to a particular channel
     *
     * @param channel the number of the channel (1 <= channel <= 13)
     *
     * @return a Ptr to a newly created SpectrumValue
     */
    virtual Ptr<SpectrumValue> CreateRfFilter(uint8_t channel);
};

} // namespace ns3

#endif /*  WIFI_SPECTRUM_VALUE_HELPER_H */
