model/plc-csmaca.h

/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2011 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: kwong yin <kwong-sang.yin@boeing.com>
 */

#ifndef PLC_CSMACA_H
#define PLC_CSMACA_H

#include <stdint.h>
#include "ns3/object.h"
#include "ns3/nstime.h"
#include "ns3/random-variable.h"
#include "ns3/packet.h"
#include "ns3/plc-phy.h"

namespace ns3 {

typedef enum
{
        CHANNEL_IDLE,
        CHANNEL_ACCESS_FAILURE
 } PLC_CsmaCaState;

/* This method informs MAC that channel is idle or busy */
typedef Callback< void > PLC_CsmaCaCcaRequestCallback;
typedef Callback< void > PLC_CsmaCaCcaCancelCallback;
typedef Callback< void, PLC_CsmaCaState> PLC_CsmaCaMacCallback;

class PLC_Mac;

class PLC_CsmaCa : public Object
{

public:
  static TypeId GetTypeId ();

  PLC_CsmaCa ();
  ~PLC_CsmaCa ();

  void setSlottedCsmaCa (void);
  void setUnSlottedCsmaCa (void);
  bool isSlottedCsmaCa (void) const;
  bool isUnSlottedCsmaCa (void) const;

  void setMacMinBE (uint8_t macMinBE);
  uint8_t getMacMinBE (void) const;
  void setMacMaxBE (uint8_t macMaxBE);
  uint8_t getMacMaxBE (void) const;
  void setmacMaxCSMABackoffs (uint8_t macMaxCSMABackoffs);
  uint8_t getmacMaxCSMABackoffs (void) const;

  void setUnitBackoffPeriod (uint64_t unitBackoffPeriod);
  uint64_t getUnitBackoffPeriod (void) const;

  /*
   *  Amount of time from now to the beginning of the next slot
   */
  uint64_t getTimeToNextSlot (void) const;

  /*
   * Start CSMA-CA algorithm (step 1), initialize NB, BE for both slotted and unslotted
   * CSMA-CA. For the slotted intialize CW plus also start on the backoff boundary
   */
  void Start (void);

  /*
   * cancel CSMA-CA algorithm
   */
  void Cancel ();

  /*
   * In step 2 of the CSMA-CA, perform a random backoff in the range of 0 to 2^BE -1
   */
  void RandomBackoffDelay ();

  /*
   * In the slotted CSMA-CA, after random backoff, Determine if the remaining
   * CSMA-CA operation can proceed ie. Can the entire transactions can be transmitted
   * before the end of the CAP. This step is performed between step 2 and 3.
   * This step is NOT performed for the unslotted CSMA-CA. If it can proceed
   * function CCAconfirmed() is called.
   */
  void CanProceed ();

  /*
   * Request the Phy to perform CCA (Step 3)
   *
   */
  void RequestCCA ();

  void CcaConfirm (PLC_PhyCcaResult status);

  void SetCcaRequestCallback (PLC_CsmaCaCcaRequestCallback c);

  void SetCcaCancelCallback (PLC_CsmaCaCcaCancelCallback c);

  void SetCsmaCaMacCallback (PLC_CsmaCaMacCallback c);

  bool IsActive(void) { return m_active; }

private:
  virtual void DoDispose ();
  PLC_CsmaCaCcaRequestCallback m_csmaCaCcaRequestCallback;
  PLC_CsmaCaCcaCancelCallback m_csmaCaCcaCancelCallback;
  PLC_CsmaCaMacCallback m_csmaCaMacCallback;

  bool m_isSlotted;                     // beacon-enabled slotted or nonbeacon-enabled unslotted CSMA-CA
                                        // beacon order == 15 means nonbeacon-enabled

  uint8_t m_NB;                         // number of backoffs for the current transmission
  uint8_t m_CW;                         // contention window length (used in slotted ver only)
  uint8_t m_BE;                         // backoff exponent
  bool m_BLE;                           // Battery Life Extension

  uint8_t m_macMinBE;                   //0-macMaxBE default 3
  uint8_t m_macMaxBE;                   //3-8 default 5
  uint8_t m_macMaxCSMABackoffs;         //0-5 default 4
  uint64_t m_aUnitBackoffPeriod;        // 20 symbols in each backoff periods

  bool m_active;

  EventId m_requestCCAEvent;
  EventId m_backoffEndEvent;
  EventId m_canProceedEvent;
};

}

// namespace ns-3

#endif /* PLC_CSMACA_H */