dsss-ppdu.cc

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2020 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
 *
 * Author: Rediet <getachew.redieteab@orange.com>
 *         Muhammad Iqbal Rochman <muhiqbalcr@uchicago.edu>
 *         Sébastien Deronne <sebastien.deronne@gmail.com> (DsssSigHeader)
 */

#include "ns3/wifi-phy.h"
#include "ns3/wifi-psdu.h"
#include "dsss-phy.h"
#include "dsss-ppdu.h"
#include "ns3/log.h"

namespace ns3 {

NS_LOG_COMPONENT_DEFINE ("DsssPpdu");

DsssPpdu::DsssPpdu (Ptr<const WifiPsdu> psdu, const WifiTxVector& txVector, Time ppduDuration, uint64_t uid)
  : WifiPpdu (psdu, txVector, uid)
{
  NS_LOG_FUNCTION (this << psdu << txVector << ppduDuration << uid);
  m_dsssSig.SetRate (txVector.GetMode ().GetDataRate (22));
  Time psduDuration = ppduDuration - WifiPhy::CalculatePhyPreambleAndHeaderDuration (txVector);
  m_dsssSig.SetLength (psduDuration.GetMicroSeconds ());
}

DsssPpdu::~DsssPpdu ()
{
}

WifiTxVector
DsssPpdu::DoGetTxVector (void) const
{
  WifiTxVector txVector;
  txVector.SetPreambleType (m_preamble);
  txVector.SetMode (DsssPhy::GetDsssRate (m_dsssSig.GetRate ()));
  txVector.SetChannelWidth (22);
  return txVector;
}

Time
DsssPpdu::GetTxDuration (void) const
{
  Time ppduDuration = Seconds (0);
  const WifiTxVector& txVector = GetTxVector ();
  ppduDuration = MicroSeconds (m_dsssSig.GetLength ()) + WifiPhy::CalculatePhyPreambleAndHeaderDuration (txVector);
  return ppduDuration;
}

Ptr<WifiPpdu>
DsssPpdu::Copy (void) const
{
  return Create<DsssPpdu> (GetPsdu (), GetTxVector (), GetTxDuration (), m_uid);
}

DsssPpdu::DsssSigHeader::DsssSigHeader ()
  : m_rate (0b00001010),
    m_length (0)
{
}

DsssPpdu::DsssSigHeader::~DsssSigHeader ()
{
}

TypeId
DsssPpdu::DsssSigHeader::GetTypeId (void)
{
  static TypeId tid = TypeId ("ns3::DsssSigHeader")
    .SetParent<Header> ()
    .SetGroupName ("Wifi")
    .AddConstructor<DsssSigHeader> ()
  ;
  return tid;
}

TypeId
DsssPpdu::DsssSigHeader::GetInstanceTypeId (void) const
{
  return GetTypeId ();
}

void
DsssPpdu::DsssSigHeader::Print (std::ostream &os) const
{
  os << "SIGNAL=" << GetRate ()
     << " LENGTH=" << m_length;
}

uint32_t
DsssPpdu::DsssSigHeader::GetSerializedSize (void) const
{
  return 6;
}

void
DsssPpdu::DsssSigHeader::SetRate (uint64_t rate)
{
  /* Here is the binary representation for a given rate:
   * 1 Mbit/s: 00001010
   * 2 Mbit/s: 00010100
   * 5.5 Mbit/s: 00110111
   * 11 Mbit/s: 01101110
   */
  switch (rate)
    {
      case 1000000:
        m_rate = 0b00001010;
        break;
      case 2000000:
        m_rate = 0b00010100;
        break;
      case 5500000:
        m_rate = 0b00110111;
        break;
      case 11000000:
        m_rate = 0b01101110;
        break;
      default:
        NS_ASSERT_MSG (false, "Invalid rate");
        break;
    }
}

uint64_t
DsssPpdu::DsssSigHeader::GetRate (void) const
{
  uint64_t rate = 0;
  switch (m_rate)
    {
      case 0b00001010:
        rate = 1000000;
        break;
      case 0b00010100:
        rate = 2000000;
        break;
      case 0b00110111:
        rate = 5500000;
        break;
      case 0b01101110:
        rate = 11000000;
        break;
      default:
        NS_ASSERT_MSG (false, "Invalid rate");
        break;
    }
  return rate;
}

void
DsssPpdu::DsssSigHeader::SetLength (uint16_t length)
{
  m_length = length;
}

uint16_t
DsssPpdu::DsssSigHeader::GetLength (void) const
{
  return m_length;
}

void
DsssPpdu::DsssSigHeader::Serialize (Buffer::Iterator start) const
{
  start.WriteU8 (m_rate);
  start.WriteU8 (0); /* SERVICE */
  start.WriteU16 (m_length);
  start.WriteU16 (0); /* CRC */
}

uint32_t
DsssPpdu::DsssSigHeader::Deserialize (Buffer::Iterator start)
{
  Buffer::Iterator i = start;
  m_rate = i.ReadU8 ();
  i.ReadU8 (); /* SERVICE */
  m_length =  i.ReadU16 ();
  i.ReadU16 (); /* CRC */
  return i.GetDistanceFrom (start);
}

} //namespace ns3