bs-link-manager.cc

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/*
 * Copyright (c) 2007,2008,2009 INRIA, UDcast
 *
 * 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: Jahanzeb Farooq <jahanzeb.farooq@sophia.inria.fr>
 *          Mohamed Amine Ismail <amine.ismail@sophia.inria.fr>
 *                               <amine.ismail@UDcast.com>
 */
 
#include "bs-link-manager.h"
 
#include "bs-uplink-scheduler.h"
#include "burst-profile-manager.h"
#include "connection-manager.h"
#include "ss-manager.h"
#include "ss-record.h"
 
#include "ns3/log.h"
#include "ns3/node.h"
#include "ns3/packet.h"
#include "ns3/simulator.h"
 
#include <stdint.h>
 
namespace ns3
{
 
NS_LOG_COMPONENT_DEFINE("BSLinkManager");
 
NS_OBJECT_ENSURE_REGISTERED(BSLinkManager);
 
TypeId
BSLinkManager::GetTypeId()
{
    static TypeId tid = TypeId("ns3::BSLinkManager").SetParent<Object>().SetGroupName("Wimax");
    return tid;
}
 
BSLinkManager::BSLinkManager(Ptr<BaseStationNetDevice> bs)
    : m_bs(bs),
      m_signalQuality(10),
      m_signalQualityThreshold(10) // arbitrary value
{
    tries = 0;
}
 
BSLinkManager::~BSLinkManager()
{
    m_bs = nullptr;
}
 
uint8_t
BSLinkManager::CalculateRangingOppsToAllocate()
{
    // randomly selecting TOs up to 10, shall actually be decided by scheduler
    return rand() % 8 + 2;
}
 
/*
 * Function mainly to avoid duplicate code in DoReceive ()
 */
void
BSLinkManager::ProcessRangingRequest(Cid cid, RngReq rngreq)
{
    NS_ASSERT_MSG(m_bs->GetState() == BaseStationNetDevice::BS_STATE_UL_SUB_FRAME,
                  "Base station: Error while processing ranging request: !BS_STATE_UL_SUB_FRAME");
 
    Time irIntervalBoundary = Seconds(0);
 
    if (m_bs->GetUplinkScheduler()->GetIsInvIrIntrvlAllocated())
    {
        if (m_bs->GetUplinkScheduler()->GetIsIrIntrvlAllocated())
        {
            irIntervalBoundary =
                m_bs->GetUlSubframeStartTime() +
                Seconds((m_bs->GetUplinkScheduler()->GetNrIrOppsAllocated() + 1) *
                        m_bs->GetRangReqOppSize() * m_bs->GetSymbolDuration().GetSeconds());
        }
        else
        {
            irIntervalBoundary =
                m_bs->GetUlSubframeStartTime() +
                Seconds(m_bs->GetRangReqOppSize() * m_bs->GetSymbolDuration().GetSeconds());
        }
    }
    else
    {
        NS_ASSERT_MSG(
            m_bs->GetUplinkScheduler()->GetIsIrIntrvlAllocated(),
            "Base station: Error while processing ranging request: IR interval not allocated");
 
        irIntervalBoundary =
            m_bs->GetUlSubframeStartTime() +
            Seconds(m_bs->GetUplinkScheduler()->GetNrIrOppsAllocated() * m_bs->GetRangReqOppSize() *
                    m_bs->GetSymbolDuration().GetSeconds());
    }
 
    tries++;
 
    if (Simulator::Now() >= m_bs->GetUlSubframeStartTime() && Simulator::Now() < irIntervalBoundary)
    {
        PerformRanging(cid, rngreq);
    }
}
 
void
BSLinkManager::PerformRanging(Cid cid, RngReq rngreq)
{
    RngRsp rngrsp;
    bool decodable = false;
 
    // assuming low power, packet lost or undecodable first 2 times
    if (tries < 2)
    {
        return;
    }
    if (tries >= 3)
    {
        decodable = true;
    }
 
    NS_LOG_DEBUG("RNG-REQ:");
    rngreq.PrintDebug();
 
    if (!decodable)
    {
        rngrsp.SetFrameNumber(m_bs->GetNrFrames());
        rngrsp.SetInitRangOppNumber(m_bs->GetRangingOppNumber());
 
        SetParametersToAdjust(&rngrsp);
        rngrsp.SetRangStatus(WimaxNetDevice::RANGING_STATUS_CONTINUE); // see Figure 64
        ScheduleRngRspMessage(cid, &rngrsp);
    }
    else
    {
        if (cid.IsInitialRanging())
        {
            PerformInitialRanging(cid, &rngreq, &rngrsp);
        }
        else
        {
            // invited initial ranging or periodic ranging
            PerformInvitedRanging(cid, &rngrsp);
        }
    }
}
 
void
BSLinkManager::PerformInitialRanging(Cid cid, RngReq* rngreq, RngRsp* rngrsp)
{
    SSRecord* ssRecord = nullptr;
    bool isOldSS = m_bs->GetSSManager()->IsInRecord(rngreq->GetMacAddress());
    if (isOldSS)
    {
        ssRecord = m_bs->GetSSManager()->GetSSRecord(rngreq->GetMacAddress());
        // if this fails it would mean the RNG-RSP with success status was not received by the SS
    }
    else
    {
        ssRecord = m_bs->GetSSManager()->CreateSSRecord(rngreq->GetMacAddress());
    }
 
    if (ChangeDlChannel())
    {
        rngrsp->SetDlFreqOverride(GetNewDlChannel());
        AbortRanging(cid, rngrsp, ssRecord, isOldSS);
        return;
    }
 
    if (isOldSS)
    {
        // CIDs already assigned, e.g., RNG-REQ was lost and resent after timeout. reusing old CIDs
        ssRecord->ResetRangingCorrectionRetries();
        ssRecord->ResetInvitedRangingRetries();
    }
    else
    {
        m_bs->GetConnectionManager()->AllocateManagementConnections(ssRecord, rngrsp);
 
        WimaxPhy::ModulationType modulationType;
        uint8_t diuc =
            m_bs->GetBurstProfileManager()->GetBurstProfileForSS(ssRecord, rngreq, modulationType);
        ssRecord->SetModulationType(modulationType);
 
        // specify in RNG-RSP only if different than what SS requested
        if (rngreq->GetReqDlBurstProfile() != diuc)
        {
            rngrsp->SetDlOperBurstProfile(diuc);
        }
 
        // add SS (Basic CID) to poll list for invited ranging intervals, see Table 115
        ssRecord->EnablePollForRanging();
    }
 
    rngrsp->SetMacAddress(rngreq->GetMacAddress());
 
    if (isOldSS) // CIDs had already been allocated
    {
        cid = ssRecord->GetBasicCid();
    }
 
    if (IsRangingAcceptable())
    {
        AcceptRanging(cid, rngrsp, ssRecord);
    }
    else
    {
        ContinueRanging(cid, rngrsp, ssRecord);
    }
}
 
void
BSLinkManager::PerformInvitedRanging(Cid cid, RngRsp* rngrsp)
{
    SSRecord* ssRecord = m_bs->GetSSManager()->GetSSRecord(cid);
    ssRecord->IncrementRangingCorrectionRetries();
    ssRecord->ResetInvitedRangingRetries();
 
    if (IsRangingAcceptable())
    {
        AcceptRanging(cid, rngrsp, ssRecord);
    }
    else
    {
        if (ssRecord->GetRangingCorrectionRetries() == m_bs->GetMaxRangingCorrectionRetries())
        {
            AbortRanging(cid, rngrsp, ssRecord, true);
        }
        else
        {
            ContinueRanging(cid, rngrsp, ssRecord);
        }
    }
}
 
void
BSLinkManager::VerifyInvitedRanging(Cid cid, uint8_t uiuc)
{
    if (uiuc == OfdmUlBurstProfile::UIUC_INITIAL_RANGING)
    {
        SSRecord* ssRecord = m_bs->GetSSManager()->GetSSRecord(cid);
        if (ssRecord->GetInvitedRangRetries() > 0)
        {
            ssRecord->IncrementInvitedRangingRetries();
 
            if (ssRecord->GetInvitedRangRetries() == m_bs->GetMaxInvitedRangRetries())
            {
                auto rngrsp = new RngRsp();
                AbortRanging(ssRecord->GetBasicCid(), rngrsp, ssRecord, true);
            } // else keep polling
        }
    }
}
 
void
BSLinkManager::SetParametersToAdjust(RngRsp* rngrsp)
{
    // code to calculate parameter adjustment values goes here
    rngrsp->SetTimingAdjust(40);
    rngrsp->SetPowerLevelAdjust(8);
    rngrsp->SetOffsetFreqAdjust(30);
}
 
void
BSLinkManager::AbortRanging(Cid cid, RngRsp* rngrsp, SSRecord* ssRecord, bool isOldSS)
{
    rngrsp->SetRangStatus(WimaxNetDevice::RANGING_STATUS_ABORT);
    ScheduleRngRspMessage(cid, rngrsp);
 
    if (isOldSS)
    {
        ssRecord->SetRangingStatus(WimaxNetDevice::RANGING_STATUS_ABORT);
    }
 
    ssRecord->DisablePollForRanging();
    DeallocateCids(cid);
}
 
void
BSLinkManager::AcceptRanging(Cid cid, RngRsp* rngrsp, SSRecord* ssRecord)
{
    rngrsp->SetRangStatus(WimaxNetDevice::RANGING_STATUS_SUCCESS);
    ScheduleRngRspMessage(cid, rngrsp);
 
    /*Shall not be set until the SS receives the RNG-RSP, as it may be lost etc. may be state field
     is also added to SSRecord which then set to SS_STATE_REGISTERED once confirmed that SS has
     received this RNG-RSP, but how to determine that, may be as a data packet is received by the
     SS*/
    ssRecord->SetRangingStatus(WimaxNetDevice::RANGING_STATUS_SUCCESS);
 
    ssRecord->DisablePollForRanging();
}
 
void
BSLinkManager::ContinueRanging(Cid cid, RngRsp* rngrsp, SSRecord* ssRecord)
{
    rngrsp->SetRangStatus(WimaxNetDevice::RANGING_STATUS_CONTINUE);
    ScheduleRngRspMessage(cid, rngrsp);
    ssRecord->SetRangingStatus(WimaxNetDevice::RANGING_STATUS_CONTINUE);
}
 
void
BSLinkManager::ScheduleRngRspMessage(Cid cid, RngRsp* rngrsp)
{
    if (rngrsp->GetRangStatus() == WimaxNetDevice::RANGING_STATUS_SUCCESS ||
        rngrsp->GetRangStatus() == WimaxNetDevice::RANGING_STATUS_CONTINUE)
    {
        SetParametersToAdjust(rngrsp);
    }
 
    Ptr<Packet> p = Create<Packet>();
    p->AddHeader(*rngrsp);
    p->AddHeader(ManagementMessageType(ManagementMessageType::MESSAGE_TYPE_RNG_RSP));
 
    m_bs->Enqueue(p, MacHeaderType(), m_bs->GetConnection(cid));
}
 
void
BSLinkManager::DeallocateCids(Cid cid)
{
    // if necessary, delete entire connections or simply set CIDs to 0
}
 
uint64_t
BSLinkManager::SelectDlChannel()
{
    // Values according to WirelessMAN-OFDM RF profile for 10 MHz channelization
    // Section 12.3.3.1 from IEEE 802.16-2004 standard
    // profR10_3 :
    // channels: 5000 + n ⋅ 5 MHz, ∀n ∈ { 147, 149, 151, 153, 155, 157, 159, 161, 163, 165,
    // 167 } temporarily set to 1 for quick scanning. To be standard compliant, use a value in the
    // list above
    return m_bs->GetChannel(1);
}
 
bool
BSLinkManager::ChangeDlChannel()
{
    // code to decide if SS shall move to a new channel/frequency goes here
    return false;
}
 
uint32_t
BSLinkManager::GetNewDlChannel()
{
    // code to determine suggested new frequency goes here
    return 100;
}
 
uint8_t
BSLinkManager::GetSignalQuality()
{
    // code to measure signal quality goes here
    uint8_t signalQuality = m_signalQuality;
    m_signalQuality++;
    return signalQuality;
}
 
bool
BSLinkManager::IsRangingAcceptable()
{
    return GetSignalQuality() > m_signalQualityThreshold;
}
 
} // namespace ns3