/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2011 Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)

 *

 * 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: Marco Miozzo <marco.miozzo@cttc.es>        // original version

 * Modification: Dizhi Zhou <dizhi.zhou@gmail.com>    // modify codes related to downlink scheduler

 */

#include <ns3/log.h>

#include <ns3/pointer.h>

#include <ns3/integer.h>

#include <ns3/simulator.h>

#include <ns3/lte-amc.h>

#include <ns3/fdtbfq-ff-mac-scheduler.h>

#include <ns3/lte-vendor-specific-parameters.h>

NS_LOG_COMPONENT_DEFINE ("FdTbfqFfMacScheduler");

// value for SINR outside the range defined by LTE, used to indicate that there

// is no CQI for this element

#define NO_SINR -5000

namespace ns3 {

int FdTbfqType0AllocationRbg[4] = {

  10,       // RGB size 1

  26,       // RGB size 2

  63,       // RGB size 3

  110       // RGB size 4

};  // see table 7.1.6.1-1 of 36.213

NS_OBJECT_ENSURE_REGISTERED (FdTbfqFfMacScheduler);

class FdTbfqSchedulerMemberCschedSapProvider : public FfMacCschedSapProvider

{

public:

  FdTbfqSchedulerMemberCschedSapProvider (FdTbfqFfMacScheduler* scheduler);

  // inherited from FfMacCschedSapProvider

  virtual void CschedCellConfigReq (const struct CschedCellConfigReqParameters& params);

  virtual void CschedUeConfigReq (const struct CschedUeConfigReqParameters& params);

  virtual void CschedLcConfigReq (const struct CschedLcConfigReqParameters& params);

  virtual void CschedLcReleaseReq (const struct CschedLcReleaseReqParameters& params);

  virtual void CschedUeReleaseReq (const struct CschedUeReleaseReqParameters& params);

private:

  FdTbfqSchedulerMemberCschedSapProvider ();

  FdTbfqFfMacScheduler* m_scheduler;

};

FdTbfqSchedulerMemberCschedSapProvider::FdTbfqSchedulerMemberCschedSapProvider ()

{

}

FdTbfqSchedulerMemberCschedSapProvider::FdTbfqSchedulerMemberCschedSapProvider (FdTbfqFfMacScheduler* scheduler) : m_scheduler (scheduler)

{

}

void

FdTbfqSchedulerMemberCschedSapProvider::CschedCellConfigReq (const struct CschedCellConfigReqParameters& params)

{

  m_scheduler->DoCschedCellConfigReq (params);

}

void

FdTbfqSchedulerMemberCschedSapProvider::CschedUeConfigReq (const struct CschedUeConfigReqParameters& params)

{

  m_scheduler->DoCschedUeConfigReq (params);

}

void

FdTbfqSchedulerMemberCschedSapProvider::CschedLcConfigReq (const struct CschedLcConfigReqParameters& params)

{

  m_scheduler->DoCschedLcConfigReq (params);

}

void

FdTbfqSchedulerMemberCschedSapProvider::CschedLcReleaseReq (const struct CschedLcReleaseReqParameters& params)

{

  m_scheduler->DoCschedLcReleaseReq (params);

}

void

FdTbfqSchedulerMemberCschedSapProvider::CschedUeReleaseReq (const struct CschedUeReleaseReqParameters& params)

{

  m_scheduler->DoCschedUeReleaseReq (params);

}

class FdTbfqSchedulerMemberSchedSapProvider : public FfMacSchedSapProvider

{

public:

  FdTbfqSchedulerMemberSchedSapProvider (FdTbfqFfMacScheduler* scheduler);

  // inherited from FfMacSchedSapProvider

  virtual void SchedDlRlcBufferReq (const struct SchedDlRlcBufferReqParameters& params);

  virtual void SchedDlPagingBufferReq (const struct SchedDlPagingBufferReqParameters& params);

  virtual void SchedDlMacBufferReq (const struct SchedDlMacBufferReqParameters& params);

  virtual void SchedDlTriggerReq (const struct SchedDlTriggerReqParameters& params);

  virtual void SchedDlRachInfoReq (const struct SchedDlRachInfoReqParameters& params);

  virtual void SchedDlCqiInfoReq (const struct SchedDlCqiInfoReqParameters& params);

  virtual void SchedUlTriggerReq (const struct SchedUlTriggerReqParameters& params);

  virtual void SchedUlNoiseInterferenceReq (const struct SchedUlNoiseInterferenceReqParameters& params);

  virtual void SchedUlSrInfoReq (const struct SchedUlSrInfoReqParameters& params);

  virtual void SchedUlMacCtrlInfoReq (const struct SchedUlMacCtrlInfoReqParameters& params);

  virtual void SchedUlCqiInfoReq (const struct SchedUlCqiInfoReqParameters& params);

private:

  FdTbfqSchedulerMemberSchedSapProvider ();

  FdTbfqFfMacScheduler* m_scheduler;

};

FdTbfqSchedulerMemberSchedSapProvider::FdTbfqSchedulerMemberSchedSapProvider ()

{

}

FdTbfqSchedulerMemberSchedSapProvider::FdTbfqSchedulerMemberSchedSapProvider (FdTbfqFfMacScheduler* scheduler)

  : m_scheduler (scheduler)

{

}

void

FdTbfqSchedulerMemberSchedSapProvider::SchedDlRlcBufferReq (const struct SchedDlRlcBufferReqParameters& params)

{

  m_scheduler->DoSchedDlRlcBufferReq (params);

}

void

FdTbfqSchedulerMemberSchedSapProvider::SchedDlPagingBufferReq (const struct SchedDlPagingBufferReqParameters& params)

{

  m_scheduler->DoSchedDlPagingBufferReq (params);

}

void

FdTbfqSchedulerMemberSchedSapProvider::SchedDlMacBufferReq (const struct SchedDlMacBufferReqParameters& params)

{

  m_scheduler->DoSchedDlMacBufferReq (params);

}

void

FdTbfqSchedulerMemberSchedSapProvider::SchedDlTriggerReq (const struct SchedDlTriggerReqParameters& params)

{

  m_scheduler->DoSchedDlTriggerReq (params);

}

void

FdTbfqSchedulerMemberSchedSapProvider::SchedDlRachInfoReq (const struct SchedDlRachInfoReqParameters& params)

{

  m_scheduler->DoSchedDlRachInfoReq (params);

}

void

FdTbfqSchedulerMemberSchedSapProvider::SchedDlCqiInfoReq (const struct SchedDlCqiInfoReqParameters& params)

{

  m_scheduler->DoSchedDlCqiInfoReq (params);

}

void

FdTbfqSchedulerMemberSchedSapProvider::SchedUlTriggerReq (const struct SchedUlTriggerReqParameters& params)

{

  m_scheduler->DoSchedUlTriggerReq (params);

}

void

FdTbfqSchedulerMemberSchedSapProvider::SchedUlNoiseInterferenceReq (const struct SchedUlNoiseInterferenceReqParameters& params)

{

  m_scheduler->DoSchedUlNoiseInterferenceReq (params);

}

void

FdTbfqSchedulerMemberSchedSapProvider::SchedUlSrInfoReq (const struct SchedUlSrInfoReqParameters& params)

{

  m_scheduler->DoSchedUlSrInfoReq (params);

}

void

FdTbfqSchedulerMemberSchedSapProvider::SchedUlMacCtrlInfoReq (const struct SchedUlMacCtrlInfoReqParameters& params)

{

  m_scheduler->DoSchedUlMacCtrlInfoReq (params);

}

void

FdTbfqSchedulerMemberSchedSapProvider::SchedUlCqiInfoReq (const struct SchedUlCqiInfoReqParameters& params)

{

  m_scheduler->DoSchedUlCqiInfoReq (params);

}

FdTbfqFfMacScheduler::FdTbfqFfMacScheduler ()

  :   m_cschedSapUser (0),

    m_schedSapUser (0),

    m_timeWindow (99.0),

    m_nextRntiUl (0)

{

  m_amc = CreateObject <LteAmc> ();

  m_cschedSapProvider = new FdTbfqSchedulerMemberCschedSapProvider (this);

  m_schedSapProvider = new FdTbfqSchedulerMemberSchedSapProvider (this);

}

FdTbfqFfMacScheduler::~FdTbfqFfMacScheduler ()

{

  NS_LOG_FUNCTION (this);

}

void

FdTbfqFfMacScheduler::DoDispose ()

{

  NS_LOG_FUNCTION (this);

  delete m_cschedSapProvider;

  delete m_schedSapProvider;

}

TypeId

FdTbfqFfMacScheduler::GetTypeId (void)

{

  static TypeId tid = TypeId ("ns3::FdTbfqFfMacScheduler")

    .SetParent<FfMacScheduler> ()

    .AddConstructor<FdTbfqFfMacScheduler> ()

    .AddAttribute ("CqiTimerThreshold",

                   "The number of TTIs a CQI is valid (default 1000 - 1 sec.)",

                   UintegerValue (1000),

                   MakeUintegerAccessor (&FdTbfqFfMacScheduler::m_cqiTimersThreshold),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("DebtLimit",

                   "Flow debt limit (default -625000 bytes)",

                   IntegerValue (-625000),

                   MakeIntegerAccessor (&FdTbfqFfMacScheduler::m_debtLimit),

                   MakeIntegerChecker<int> ())

    .AddAttribute ("CreditLimit",

                   "Flow credit limit (default 625000 bytes)",

                   UintegerValue (625000),

                   MakeUintegerAccessor (&FdTbfqFfMacScheduler::m_creditLimit),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("TokenPoolSize",

                   "The maximum value of flow token pool (default 1 bytes)",

                   UintegerValue (1),

                   MakeUintegerAccessor (&FdTbfqFfMacScheduler::m_tokenPoolSize),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("CreditableThreshold",

                   "Threshold of flow credit (default 0 bytes)",

                   UintegerValue (0),

                   MakeUintegerAccessor (&FdTbfqFfMacScheduler::m_creditableThreshold),

                   MakeUintegerChecker<uint32_t> ())

  ;

  return tid;

}

void

FdTbfqFfMacScheduler::SetFfMacCschedSapUser (FfMacCschedSapUser* s)

{

  m_cschedSapUser = s;

}

void

FdTbfqFfMacScheduler::SetFfMacSchedSapUser (FfMacSchedSapUser* s)

{

  m_schedSapUser = s;

}

FfMacCschedSapProvider*

FdTbfqFfMacScheduler::GetFfMacCschedSapProvider ()

{

  return m_cschedSapProvider;

}

FfMacSchedSapProvider*

FdTbfqFfMacScheduler::GetFfMacSchedSapProvider ()

{

  return m_schedSapProvider;

}

void

FdTbfqFfMacScheduler::DoCschedCellConfigReq (const struct FfMacCschedSapProvider::CschedCellConfigReqParameters& params)

{

  NS_LOG_FUNCTION (this);

  // Read the subset of parameters used

  m_cschedCellConfig = params;

  FfMacCschedSapUser::CschedUeConfigCnfParameters cnf;

  cnf.m_result = SUCCESS;

  m_cschedSapUser->CschedUeConfigCnf (cnf);

  return;

}

void

FdTbfqFfMacScheduler::DoCschedUeConfigReq (const struct FfMacCschedSapProvider::CschedUeConfigReqParameters& params)

{

  NS_LOG_FUNCTION (this << " RNTI " << params.m_rnti << " txMode " << (uint16_t)params.m_transmissionMode);

  std::map <uint16_t,uint8_t>::iterator it = m_uesTxMode.find (params.m_rnti);

  if (it == m_uesTxMode.end ())

    {

      m_uesTxMode.insert (std::pair <uint16_t, double> (params.m_rnti, params.m_transmissionMode));

    }

  else

    {

      (*it).second = params.m_transmissionMode;

    }

  return;

}

void

FdTbfqFfMacScheduler::DoCschedLcConfigReq (const struct FfMacCschedSapProvider::CschedLcConfigReqParameters& params)

{

  NS_LOG_FUNCTION (this << " New LC, rnti: "  << params.m_rnti);

  std::map <uint16_t, fdtbfqsFlowPerf_t>::iterator it;

  for (uint16_t i = 0; i < params.m_logicalChannelConfigList.size (); i++)

    {

      it = m_flowStatsDl.find (params.m_rnti);

      if (it == m_flowStatsDl.end ())

        {

          uint64_t mbrDlInBytes = params.m_logicalChannelConfigList.at (i).m_eRabMaximulBitrateDl / 8;   // byte/s

          uint64_t mbrUlInBytes = params.m_logicalChannelConfigList.at (i).m_eRabMaximulBitrateUl / 8;   // byte/s

          fdtbfqsFlowPerf_t flowStatsDl;

          flowStatsDl.flowStart = Simulator::Now ();

          flowStatsDl.packetArrivalRate = 0;

          flowStatsDl.tokenGenerationRate =  mbrDlInBytes;

          flowStatsDl.tokenPoolSize = 0;

          flowStatsDl.maxTokenPoolSize = m_tokenPoolSize;

          flowStatsDl.counter = 0;

          flowStatsDl.burstCredit = m_creditLimit; // bytes

          flowStatsDl.debtLimit = m_debtLimit; // bytes

          flowStatsDl.creditableThreshold = m_creditableThreshold;

          m_flowStatsDl.insert (std::pair<uint16_t, fdtbfqsFlowPerf_t> (params.m_rnti, flowStatsDl));

          fdtbfqsFlowPerf_t flowStatsUl;

          flowStatsUl.flowStart = Simulator::Now ();

          flowStatsUl.packetArrivalRate = 0;

          flowStatsUl.tokenGenerationRate = mbrUlInBytes;

          flowStatsUl.tokenPoolSize = 0;

          flowStatsUl.maxTokenPoolSize = m_tokenPoolSize;

          flowStatsUl.counter = 0;

          flowStatsUl.burstCredit = m_creditLimit;  // bytes

          flowStatsUl.debtLimit = m_debtLimit;  // bytes

          flowStatsUl.creditableThreshold = m_creditableThreshold;

          m_flowStatsUl.insert (std::pair<uint16_t, fdtbfqsFlowPerf_t> (params.m_rnti, flowStatsUl));

        }

      else

        {

          NS_LOG_ERROR ("RNTI already exists");

        }

    }

  return;

}

void

FdTbfqFfMacScheduler::DoCschedLcReleaseReq (const struct FfMacCschedSapProvider::CschedLcReleaseReqParameters& params)

{

  NS_LOG_FUNCTION (this);

  // TODO: Implementation of the API

  return;

}

void

FdTbfqFfMacScheduler::DoCschedUeReleaseReq (const struct FfMacCschedSapProvider::CschedUeReleaseReqParameters& params)

{

  NS_LOG_FUNCTION (this);

  // TODO: Implementation of the API

  return;

}

void

FdTbfqFfMacScheduler::DoSchedDlRlcBufferReq (const struct FfMacSchedSapProvider::SchedDlRlcBufferReqParameters& params)

{

  NS_LOG_FUNCTION (this << params.m_rnti << (uint32_t) params.m_logicalChannelIdentity);

  // API generated by RLC for updating RLC parameters on a LC (tx and retx queues)

  std::map <LteFlowId_t, FfMacSchedSapProvider::SchedDlRlcBufferReqParameters>::iterator it;

  LteFlowId_t flow (params.m_rnti, params.m_logicalChannelIdentity);

  it =  m_rlcBufferReq.find (flow);

  if (it == m_rlcBufferReq.end ())

    {

      m_rlcBufferReq.insert (std::pair <LteFlowId_t, FfMacSchedSapProvider::SchedDlRlcBufferReqParameters> (flow, params));

    }

  else

    {

      (*it).second = params;

    }

  return;

}

void

FdTbfqFfMacScheduler::DoSchedDlPagingBufferReq (const struct FfMacSchedSapProvider::SchedDlPagingBufferReqParameters& params)

{

  NS_LOG_FUNCTION (this);

  // TODO: Implementation of the API

  return;

}

void

FdTbfqFfMacScheduler::DoSchedDlMacBufferReq (const struct FfMacSchedSapProvider::SchedDlMacBufferReqParameters& params)

{

  NS_LOG_FUNCTION (this);

  // TODO: Implementation of the API

  return;

}

int

FdTbfqFfMacScheduler::GetRbgSize (int dlbandwidth)

{

  for (int i = 0; i < 4; i++)

    {

      if (dlbandwidth < FdTbfqType0AllocationRbg[i])

        {

          return (i + 1);

        }

    }

  return (-1);

}

int 

FdTbfqFfMacScheduler::LcActivePerFlow (uint16_t rnti)

{

  std::map <LteFlowId_t, FfMacSchedSapProvider::SchedDlRlcBufferReqParameters>::iterator it;

  int lcActive = 0;

  for (it = m_rlcBufferReq.begin (); it != m_rlcBufferReq.end (); it++)

    {

      if (((*it).first.m_rnti == rnti) && (((*it).second.m_rlcTransmissionQueueSize > 0)

                                           || ((*it).second.m_rlcRetransmissionQueueSize > 0)

                                           || ((*it).second.m_rlcStatusPduSize > 0) ))

        {

          lcActive++;

        }

      if ((*it).first.m_rnti > rnti)

        {

          break;

        }

    }

  return (lcActive);

}

void

FdTbfqFfMacScheduler::DoSchedDlTriggerReq (const struct FfMacSchedSapProvider::SchedDlTriggerReqParameters& params)

{

  NS_LOG_FUNCTION (this << " Frame no. " << (params.m_sfnSf >> 4) << " subframe no. " << (0xF & params.m_sfnSf));

  // API generated by RLC for triggering the scheduling of a DL subframe

  // evaluate the relative channel quality indicator for each UE per each RBG 

  // (since we are using allocation type 0 the small unit of allocation is RBG)

  // Resource allocation type 0 (see sec 7.1.6.1 of 36.213)

  RefreshDlCqiMaps ();

  // update token pool, counter and bank size

  std::map <uint16_t, fdtbfqsFlowPerf_t>::iterator itStats;

  for (itStats = m_flowStatsDl.begin (); itStats != m_flowStatsDl.end (); itStats++)

    {

      if ( (*itStats).second.tokenGenerationRate / 1000 +  (*itStats).second.tokenPoolSize > (*itStats).second.maxTokenPoolSize )     

        {

          (*itStats).second.counter +=  (*itStats).second.tokenGenerationRate / 1000 - ( (*itStats).second.maxTokenPoolSize -  (*itStats).second.tokenPoolSize );

          (*itStats).second.tokenPoolSize = (*itStats).second.maxTokenPoolSize;

          bankSize += (*itStats).second.tokenGenerationRate / 1000 - ( (*itStats).second.maxTokenPoolSize -  (*itStats).second.tokenPoolSize );

        }

      else

        {

          (*itStats).second.tokenPoolSize += (*itStats).second.tokenGenerationRate / 1000;

        }

    }

  int rbgSize = GetRbgSize (m_cschedCellConfig.m_dlBandwidth);

  int rbgNum = m_cschedCellConfig.m_dlBandwidth / rbgSize;

  std::map <uint16_t, std::vector <uint16_t> > allocationMap;

  std::set <uint16_t> allocatedRnti;   // store UEs which are already assigned RBGs

  std::set <uint8_t> allocatedRbg;  // store RBGs which are already allocated to UE

  int totalRbg = 0;

  while (totalRbg < rbgNum)

    {

      // select UE with largest metric

      std::map <uint16_t, fdtbfqsFlowPerf_t>::iterator it;

      std::map <uint16_t, fdtbfqsFlowPerf_t>::iterator itMax = m_flowStatsDl.end ();

      double metricMax;

      bool firstRnti = true;

      for (it = m_flowStatsDl.begin (); it != m_flowStatsDl.end (); it++)

        {

          if (LcActivePerFlow ((*it).first) == 0)

            {

              continue;

            }

		      std::set <uint16_t>::iterator rnti;

          rnti = allocatedRnti.find((*it).first);

		      if (rnti != allocatedRnti.end ())  //  already allocated RBGs to this UE

		        {

		          continue;

		        }

		      double metric = ( ( (double)(*it).second.counter ) / ( (double)(*it).second.tokenGenerationRate ) );

		      if (firstRnti == true)

		        {

		          metricMax = metric;