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class-a-end-device-lorawan-mac.cc
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/*
* Copyright (c) 2017 University of Padova
*
* 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: Davide Magrin <[email protected]>
* Martina Capuzzo <[email protected]>
*
* Modified by: Peggy Anderson <[email protected]>
* qiuyukang <[email protected]>
*/
#include "class-a-end-device-lorawan-mac.h"
#include "end-device-lora-phy.h"
#include "end-device-lorawan-mac.h"
#include "ns3/log.h"
#include <algorithm>
namespace ns3
{
namespace lorawan
{
NS_LOG_COMPONENT_DEFINE("ClassAEndDeviceLorawanMac");
NS_OBJECT_ENSURE_REGISTERED(ClassAEndDeviceLorawanMac);
TypeId
ClassAEndDeviceLorawanMac::GetTypeId()
{
static TypeId tid = TypeId("ns3::ClassAEndDeviceLorawanMac")
.SetParent<EndDeviceLorawanMac>()
.SetGroupName("lorawan")
.AddConstructor<ClassAEndDeviceLorawanMac>();
return tid;
}
ClassAEndDeviceLorawanMac::ClassAEndDeviceLorawanMac()
: // LoraWAN default
m_receiveDelay1(Seconds(1)),
// LoraWAN default
m_receiveDelay2(Seconds(2)),
m_rx1DrOffset(0)
{
NS_LOG_FUNCTION(this);
// Void the two receiveWindow events
m_closeFirstWindow = EventId();
m_closeFirstWindow.Cancel();
m_closeSecondWindow = EventId();
m_closeSecondWindow.Cancel();
m_secondReceiveWindow = EventId();
m_secondReceiveWindow.Cancel();
}
ClassAEndDeviceLorawanMac::~ClassAEndDeviceLorawanMac()
{
NS_LOG_FUNCTION_NOARGS();
}
/////////////////////
// Sending methods //
/////////////////////
void
ClassAEndDeviceLorawanMac::SendToPhy(Ptr<Packet> packetToSend)
{
/////////////////////////////////////////////////////////
// Add headers, prepare TX parameters and send the packet
/////////////////////////////////////////////////////////
NS_LOG_DEBUG("PacketToSend: " << packetToSend);
// Data rate adaptation as in LoRaWAN specification, V1.0.2 (2016)
if (m_enableDRAdapt && (m_dataRate > 0) && (m_retxParams.retxLeft < m_maxNumbTx) &&
(m_retxParams.retxLeft % 2 == 0))
{
m_txPower = 14; // Reset transmission power
m_dataRate = m_dataRate - 1;
}
// Craft LoraTxParameters object
LoraTxParameters params;
params.sf = GetSfFromDataRate(m_dataRate);
params.headerDisabled = m_headerDisabled;
params.codingRate = m_codingRate;
params.bandwidthHz = GetBandwidthFromDataRate(m_dataRate);
params.nPreamble = m_nPreambleSymbols;
params.crcEnabled = true;
params.lowDataRateOptimizationEnabled = LoraPhy::GetTSym(params) > MilliSeconds(16);
// Wake up PHY layer and directly send the packet
Ptr<LogicalLoraChannel> txChannel = GetChannelForTx();
NS_LOG_DEBUG("PacketToSend: " << packetToSend);
m_phy->Send(packetToSend, params, txChannel->GetFrequency(), m_txPower);
//////////////////////////////////////////////
// Register packet transmission for duty cycle
//////////////////////////////////////////////
// Compute packet duration
Time duration = m_phy->GetOnAirTime(packetToSend, params);
// Register the sent packet into the DutyCycleHelper
m_channelHelper.AddEvent(duration, txChannel);
//////////////////////////////
// Prepare for the downlink //
//////////////////////////////
// Switch the PHY to the channel so that it will listen here for downlink
m_phy->GetObject<EndDeviceLoraPhy>()->SetFrequency(txChannel->GetFrequency());
// Instruct the PHY on the right Spreading Factor to listen for during the window
// create a SetReplyDataRate function?
uint8_t replyDataRate = GetFirstReceiveWindowDataRate();
NS_LOG_DEBUG("m_dataRate: " << unsigned(m_dataRate)
<< ", m_rx1DrOffset: " << unsigned(m_rx1DrOffset)
<< ", replyDataRate: " << unsigned(replyDataRate) << ".");
m_phy->GetObject<EndDeviceLoraPhy>()->SetSpreadingFactor(GetSfFromDataRate(replyDataRate));
}
//////////////////////////
// Receiving methods //
//////////////////////////
void
ClassAEndDeviceLorawanMac::Receive(Ptr<const Packet> packet)
{
NS_LOG_FUNCTION(this << packet);
// Work on a copy of the packet
Ptr<Packet> packetCopy = packet->Copy();
// Remove the Mac Header to get some information
LorawanMacHeader mHdr;
packetCopy->RemoveHeader(mHdr);
NS_LOG_DEBUG("Mac Header: " << mHdr);
// Only keep analyzing the packet if it's downlink
if (!mHdr.IsUplink())
{
NS_LOG_INFO("Found a downlink packet.");
// Remove the Frame Header
LoraFrameHeader fHdr;
fHdr.SetAsDownlink();
packetCopy->RemoveHeader(fHdr);
NS_LOG_DEBUG("Frame Header: " << fHdr);
// Determine whether this packet is for us
bool messageForUs = (m_address == fHdr.GetAddress());
if (messageForUs)
{
NS_LOG_INFO("The message is for us!");
// If it exists, cancel the second receive window event
// THIS WILL BE GetReceiveWindow()
Simulator::Cancel(m_secondReceiveWindow);
// Parse the MAC commands
ParseCommands(fHdr);
// TODO Pass the packet up to the NetDevice
// Call the trace source
m_receivedPacket(packet);
}
else
{
NS_LOG_DEBUG("The message is intended for another recipient.");
// In this case, we are either receiving in the first receive window
// and finishing reception inside the second one, or receiving a
// packet in the second receive window and finding out, after the
// fact, that the packet is not for us. In either case, if we no
// longer have any retransmissions left, we declare failure.
if (m_retxParams.waitingAck && m_secondReceiveWindow.IsExpired())
{
if (m_retxParams.retxLeft == 0)
{
uint8_t txs = m_maxNumbTx - (m_retxParams.retxLeft);
m_requiredTxCallback(txs,
false,
m_retxParams.firstAttempt,
m_retxParams.packet);
NS_LOG_DEBUG("Failure: no more retransmissions left. Used "
<< unsigned(txs) << " transmissions.");
// Reset retransmission parameters
resetRetransmissionParameters();
}
else // Reschedule
{
this->Send(m_retxParams.packet);
NS_LOG_INFO("We have " << unsigned(m_retxParams.retxLeft)
<< " retransmissions left: rescheduling transmission.");
}
}
}
}
else if (m_retxParams.waitingAck && m_secondReceiveWindow.IsExpired())
{
NS_LOG_INFO("The packet we are receiving is in uplink.");
if (m_retxParams.retxLeft > 0)
{
this->Send(m_retxParams.packet);
NS_LOG_INFO("We have " << unsigned(m_retxParams.retxLeft)
<< " retransmissions left: rescheduling transmission.");
}
else
{
uint8_t txs = m_maxNumbTx - (m_retxParams.retxLeft);
m_requiredTxCallback(txs, false, m_retxParams.firstAttempt, m_retxParams.packet);
NS_LOG_DEBUG("Failure: no more retransmissions left. Used " << unsigned(txs)
<< " transmissions.");
// Reset retransmission parameters
resetRetransmissionParameters();
}
}
m_phy->GetObject<EndDeviceLoraPhy>()->SwitchToSleep();
}
void
ClassAEndDeviceLorawanMac::FailedReception(Ptr<const Packet> packet)
{
NS_LOG_FUNCTION(this << packet);
// Switch to sleep after a failed reception
m_phy->GetObject<EndDeviceLoraPhy>()->SwitchToSleep();
if (m_secondReceiveWindow.IsExpired() && m_retxParams.waitingAck)
{
if (m_retxParams.retxLeft > 0)
{
this->Send(m_retxParams.packet);
NS_LOG_INFO("We have " << unsigned(m_retxParams.retxLeft)
<< " retransmissions left: rescheduling transmission.");
}
else
{
uint8_t txs = m_maxNumbTx - (m_retxParams.retxLeft);
m_requiredTxCallback(txs, false, m_retxParams.firstAttempt, m_retxParams.packet);
NS_LOG_DEBUG("Failure: no more retransmissions left. Used " << unsigned(txs)
<< " transmissions.");
// Reset retransmission parameters
resetRetransmissionParameters();
}
}
}
void
ClassAEndDeviceLorawanMac::TxFinished(Ptr<const Packet> packet)
{
NS_LOG_FUNCTION_NOARGS();
// Schedule the opening of the first receive window
Simulator::Schedule(m_receiveDelay1, &ClassAEndDeviceLorawanMac::OpenFirstReceiveWindow, this);
// Schedule the opening of the second receive window
m_secondReceiveWindow = Simulator::Schedule(m_receiveDelay2,
&ClassAEndDeviceLorawanMac::OpenSecondReceiveWindow,
this);
// // Schedule the opening of the first receive window
// Simulator::Schedule (m_receiveDelay1,
// &ClassAEndDeviceLorawanMac::OpenFirstReceiveWindow, this);
//
// // Schedule the opening of the second receive window
// m_secondReceiveWindow = Simulator::Schedule (m_receiveDelay2,
// &ClassAEndDeviceLorawanMac::OpenSecondReceiveWindow,
// this);
// Switch the PHY to sleep
m_phy->GetObject<EndDeviceLoraPhy>()->SwitchToSleep();
}
void
ClassAEndDeviceLorawanMac::OpenFirstReceiveWindow()
{
NS_LOG_FUNCTION_NOARGS();
// Set Phy in Standby mode
m_phy->GetObject<EndDeviceLoraPhy>()->SwitchToStandby();
// Calculate the duration of a single symbol for the first receive window data rate
double tSym = pow(2, GetSfFromDataRate(GetFirstReceiveWindowDataRate())) /
GetBandwidthFromDataRate(GetFirstReceiveWindowDataRate());
// Schedule return to sleep after "at least the time required by the end
// device's radio transceiver to effectively detect a downlink preamble"
// (LoraWAN specification)
m_closeFirstWindow = Simulator::Schedule(Seconds(m_receiveWindowDurationInSymbols * tSym),
&ClassAEndDeviceLorawanMac::CloseFirstReceiveWindow,
this); // m_receiveWindowDuration
}
void
ClassAEndDeviceLorawanMac::CloseFirstReceiveWindow()
{
NS_LOG_FUNCTION_NOARGS();
Ptr<EndDeviceLoraPhy> phy = m_phy->GetObject<EndDeviceLoraPhy>();
// Check the Phy layer's state:
// - RX -> We are receiving a preamble.
// - STANDBY -> Nothing was received.
// - SLEEP -> We have received a packet.
// We should never be in TX or SLEEP mode at this point
switch (phy->GetState())
{
case EndDeviceLoraPhy::TX:
NS_ABORT_MSG("PHY was in TX mode when attempting to "
<< "close a receive window.");
break;
case EndDeviceLoraPhy::RX:
// PHY is receiving: let it finish. The Receive method will switch it back to SLEEP.
case EndDeviceLoraPhy::SLEEP:
// PHY has received, and the MAC's Receive already put the device to sleep
break;
case EndDeviceLoraPhy::STANDBY:
// Turn PHY layer to SLEEP
phy->SwitchToSleep();
break;
}
}
void
ClassAEndDeviceLorawanMac::OpenSecondReceiveWindow()
{
NS_LOG_FUNCTION_NOARGS();
// Check for receiver status: if it's locked on a packet, don't open this
// window at all.
if (m_phy->GetObject<EndDeviceLoraPhy>()->GetState() == EndDeviceLoraPhy::RX)
{
NS_LOG_INFO("Won't open second receive window since we are in RX mode.");
return;
}
// Set Phy in Standby mode
m_phy->GetObject<EndDeviceLoraPhy>()->SwitchToStandby();
// Switch to appropriate channel and data rate
NS_LOG_INFO("Using parameters: " << m_secondReceiveWindowFrequency << "Hz, DR"
<< unsigned(m_secondReceiveWindowDataRate));
m_phy->GetObject<EndDeviceLoraPhy>()->SetFrequency(m_secondReceiveWindowFrequency);
m_phy->GetObject<EndDeviceLoraPhy>()->SetSpreadingFactor(
GetSfFromDataRate(m_secondReceiveWindowDataRate));
// Calculate the duration of a single symbol for the second receive window data rate
double tSym = pow(2, GetSfFromDataRate(GetSecondReceiveWindowDataRate())) /
GetBandwidthFromDataRate(GetSecondReceiveWindowDataRate());
// Schedule return to sleep after "at least the time required by the end
// device's radio transceiver to effectively detect a downlink preamble"
// (LoraWAN specification)
m_closeSecondWindow = Simulator::Schedule(Seconds(m_receiveWindowDurationInSymbols * tSym),
&ClassAEndDeviceLorawanMac::CloseSecondReceiveWindow,
this);
}
void
ClassAEndDeviceLorawanMac::CloseSecondReceiveWindow()
{
NS_LOG_FUNCTION_NOARGS();
Ptr<EndDeviceLoraPhy> phy = m_phy->GetObject<EndDeviceLoraPhy>();
// NS_ASSERT (phy->m_state != EndDeviceLoraPhy::TX &&
// phy->m_state != EndDeviceLoraPhy::SLEEP);
// Check the Phy layer's state:
// - RX -> We have received a preamble.
// - STANDBY -> Nothing was detected.
switch (phy->GetState())
{
case EndDeviceLoraPhy::TX:
case EndDeviceLoraPhy::SLEEP:
break;
case EndDeviceLoraPhy::RX:
// PHY is receiving: let it finish
NS_LOG_DEBUG("PHY is receiving: Receive will handle the result.");
return;
case EndDeviceLoraPhy::STANDBY:
// Turn PHY layer to sleep
phy->SwitchToSleep();
break;
}
if (m_retxParams.waitingAck)
{
NS_LOG_DEBUG("No reception initiated by PHY: rescheduling transmission.");
if (m_retxParams.retxLeft > 0)
{
NS_LOG_INFO("We have " << unsigned(m_retxParams.retxLeft)
<< " retransmissions left: rescheduling transmission.");
this->Send(m_retxParams.packet);
}
else if (m_retxParams.retxLeft == 0 &&
m_phy->GetObject<EndDeviceLoraPhy>()->GetState() != EndDeviceLoraPhy::RX)
{
uint8_t txs = m_maxNumbTx - (m_retxParams.retxLeft);
m_requiredTxCallback(txs, false, m_retxParams.firstAttempt, m_retxParams.packet);
NS_LOG_DEBUG("Failure: no more retransmissions left. Used " << unsigned(txs)
<< " transmissions.");
// Reset retransmission parameters
resetRetransmissionParameters();
}
else
{
NS_ABORT_MSG("The number of retransmissions left is negative ! ");
}
}
else
{
uint8_t txs = m_maxNumbTx - (m_retxParams.retxLeft);
m_requiredTxCallback(txs, true, m_retxParams.firstAttempt, m_retxParams.packet);
NS_LOG_INFO(
"We have " << unsigned(m_retxParams.retxLeft)
<< " transmissions left. We were not transmitting confirmed messages.");
// Reset retransmission parameters
resetRetransmissionParameters();
}
}
/////////////////////////
// Getters and Setters //
/////////////////////////
Time
ClassAEndDeviceLorawanMac::GetNextClassTransmissionDelay(Time waitingTime)
{
NS_LOG_FUNCTION_NOARGS();
// This is a new packet from APP; it can not be sent until the end of the
// second receive window (if the second receive window has not closed yet)
if (!m_retxParams.waitingAck)
{
if (!m_closeFirstWindow.IsExpired() || !m_closeSecondWindow.IsExpired() ||
!m_secondReceiveWindow.IsExpired())
{
NS_LOG_WARN("Attempting to send when there are receive windows:"
<< " Transmission postponed.");
// Compute the duration of a single symbol for the second receive window data rate
double tSym = pow(2, GetSfFromDataRate(GetSecondReceiveWindowDataRate())) /
GetBandwidthFromDataRate(GetSecondReceiveWindowDataRate());
// Compute the closing time of the second receive window
Time endSecondRxWindow = Time(m_secondReceiveWindow.GetTs()) +
Seconds(m_receiveWindowDurationInSymbols * tSym);
NS_LOG_DEBUG("Duration until endSecondRxWindow for new transmission:"
<< (endSecondRxWindow - Simulator::Now()).GetSeconds());
waitingTime = std::max(waitingTime, endSecondRxWindow - Simulator::Now());
}
}
// This is a retransmitted packet, it can not be sent until the end of
// ACK_TIMEOUT (this timer starts when the second receive window was open)
else
{
double ack_timeout = m_uniformRV->GetValue(1, 3);
// Compute the duration until ACK_TIMEOUT (It may be a negative number, but it doesn't
// matter.)
Time retransmitWaitingTime =
Time(m_secondReceiveWindow.GetTs()) - Simulator::Now() + Seconds(ack_timeout);
NS_LOG_DEBUG("ack_timeout:" << ack_timeout << " retransmitWaitingTime:"
<< retransmitWaitingTime.GetSeconds());
waitingTime = std::max(waitingTime, retransmitWaitingTime);
}
return waitingTime;
}
uint8_t
ClassAEndDeviceLorawanMac::GetFirstReceiveWindowDataRate()
{
return m_replyDataRateMatrix.at(m_dataRate).at(m_rx1DrOffset);
}
void
ClassAEndDeviceLorawanMac::SetSecondReceiveWindowDataRate(uint8_t dataRate)
{
m_secondReceiveWindowDataRate = dataRate;
}
uint8_t
ClassAEndDeviceLorawanMac::GetSecondReceiveWindowDataRate() const
{
return m_secondReceiveWindowDataRate;
}
void
ClassAEndDeviceLorawanMac::SetSecondReceiveWindowFrequency(double frequencyMHz)
{
m_secondReceiveWindowFrequency = frequencyMHz;
}
double
ClassAEndDeviceLorawanMac::GetSecondReceiveWindowFrequency() const
{
return m_secondReceiveWindowFrequency;
}
/////////////////////////
// MAC command methods //
/////////////////////////
void
ClassAEndDeviceLorawanMac::OnRxClassParamSetupReq(Ptr<RxParamSetupReq> rxParamSetupReq)
{
NS_LOG_FUNCTION(this << rxParamSetupReq);
bool offsetOk = true;
bool dataRateOk = true;
uint8_t rx1DrOffset = rxParamSetupReq->GetRx1DrOffset();
uint8_t rx2DataRate = rxParamSetupReq->GetRx2DataRate();
double frequency = rxParamSetupReq->GetFrequency();
NS_LOG_FUNCTION(this << unsigned(rx1DrOffset) << unsigned(rx2DataRate) << frequency);
// Check that the desired offset is valid
if (!(0 <= rx1DrOffset && rx1DrOffset <= 5))
{
offsetOk = false;
}
// Check that the desired data rate is valid
if (GetSfFromDataRate(rx2DataRate) == 0 || GetBandwidthFromDataRate(rx2DataRate) == 0)
{
dataRateOk = false;
}
// For now, don't check for validity of frequency
m_secondReceiveWindowDataRate = rx2DataRate;
m_rx1DrOffset = rx1DrOffset;
m_secondReceiveWindowFrequency = frequency;
// Craft a RxParamSetupAns as response
NS_LOG_INFO("Adding RxParamSetupAns reply");
m_macCommandList.emplace_back(CreateObject<RxParamSetupAns>(offsetOk, dataRateOk, true));
}
} /* namespace lorawan */
} /* namespace ns3 */