logical-lora-channel-helper.cc

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/*
 * Copyright (c) 2017 University of Padova
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 * Author: Davide Magrin <magrinda@dei.unipd.it>
 */
 
#include "logical-lora-channel-helper.h"
 
#include "ns3/log.h"
#include "ns3/simulator.h"
 
namespace ns3
{
namespace lorawan
{
 
NS_LOG_COMPONENT_DEFINE("LogicalLoraChannelHelper");
 
NS_OBJECT_ENSURE_REGISTERED(LogicalLoraChannelHelper);
 
TypeId
LogicalLoraChannelHelper::GetTypeId()
{
    static TypeId tid =
        TypeId("ns3::LogicalLoraChannelHelper").SetParent<Object>().SetGroupName("lorawan");
    return tid;
}
 
LogicalLoraChannelHelper::LogicalLoraChannelHelper()
    : m_nextAggregatedTransmissionTime(Seconds(0)),
      m_aggregatedDutyCycle(1)
{
    NS_LOG_FUNCTION(this);
}
 
LogicalLoraChannelHelper::~LogicalLoraChannelHelper()
{
    NS_LOG_FUNCTION(this);
}
 
std::vector<Ptr<LogicalLoraChannel>>
LogicalLoraChannelHelper::GetChannelList()
{
    NS_LOG_FUNCTION(this);
 
    // Make a copy of the channel vector
    std::vector<Ptr<LogicalLoraChannel>> vector;
    vector.reserve(m_channelList.size());
    std::copy(m_channelList.begin(), m_channelList.end(), std::back_inserter(vector));
 
    return vector;
}
 
std::vector<Ptr<LogicalLoraChannel>>
LogicalLoraChannelHelper::GetEnabledChannelList()
{
    NS_LOG_FUNCTION(this);
 
    // Make a copy of the channel vector
    std::vector<Ptr<LogicalLoraChannel>> vector;
    vector.reserve(m_channelList.size());
    std::copy(m_channelList.begin(),
              m_channelList.end(),
              std::back_inserter(vector)); // Working on a copy
 
    std::vector<Ptr<LogicalLoraChannel>> channels;
    std::vector<Ptr<LogicalLoraChannel>>::iterator it;
    for (it = vector.begin(); it != vector.end(); it++)
    {
        if ((*it)->IsEnabledForUplink())
        {
            channels.push_back(*it);
        }
    }
 
    return channels;
}
 
Ptr<SubBand>
LogicalLoraChannelHelper::GetSubBandFromChannel(Ptr<LogicalLoraChannel> channel)
{
    return GetSubBandFromFrequency(channel->GetFrequency());
}
 
Ptr<SubBand>
LogicalLoraChannelHelper::GetSubBandFromFrequency(double frequency)
{
    // Get the SubBand this frequency belongs to
    std::list<Ptr<SubBand>>::iterator it;
    for (it = m_subBandList.begin(); it != m_subBandList.end(); it++)
    {
        if ((*it)->BelongsToSubBand(frequency))
        {
            return *it;
        }
    }
 
    NS_LOG_ERROR("Requested frequency: " << frequency);
    NS_ABORT_MSG("Warning: frequency is outside any known SubBand.");
 
    return nullptr; // If no SubBand is found, return 0
}
 
void
LogicalLoraChannelHelper::AddChannel(double frequency)
{
    NS_LOG_FUNCTION(this << frequency);
 
    // Create the new channel and increment the counter
    Ptr<LogicalLoraChannel> channel = Create<LogicalLoraChannel>(frequency);
 
    // Add it to the list
    m_channelList.push_back(channel);
 
    NS_LOG_DEBUG("Added a channel. Current number of channels in list is " << m_channelList.size());
}
 
void
LogicalLoraChannelHelper::AddChannel(Ptr<LogicalLoraChannel> logicalChannel)
{
    NS_LOG_FUNCTION(this << logicalChannel);
 
    // Add it to the list
    m_channelList.push_back(logicalChannel);
}
 
void
LogicalLoraChannelHelper::SetChannel(uint8_t chIndex, Ptr<LogicalLoraChannel> logicalChannel)
 
{
    NS_LOG_FUNCTION(this << chIndex << logicalChannel);
 
    m_channelList.at(chIndex) = logicalChannel;
}
 
void
LogicalLoraChannelHelper::AddSubBand(double firstFrequency,
                                     double lastFrequency,
                                     double dutyCycle,
                                     double maxTxPowerDbm)
{
    NS_LOG_FUNCTION(this << firstFrequency << lastFrequency);
 
    Ptr<SubBand> subBand = Create<SubBand>(firstFrequency, lastFrequency, dutyCycle, maxTxPowerDbm);
 
    m_subBandList.push_back(subBand);
}
 
void
LogicalLoraChannelHelper::AddSubBand(Ptr<SubBand> subBand)
{
    NS_LOG_FUNCTION(this << subBand);
 
    m_subBandList.push_back(subBand);
}
 
void
LogicalLoraChannelHelper::RemoveChannel(Ptr<LogicalLoraChannel> logicalChannel)
{
    // Search and remove the channel from the list
    std::vector<Ptr<LogicalLoraChannel>>::iterator it;
    for (it = m_channelList.begin(); it != m_channelList.end(); it++)
    {
        Ptr<LogicalLoraChannel> currentChannel = *it;
        if (currentChannel == logicalChannel)
        {
            m_channelList.erase(it);
            return;
        }
    }
}
 
Time
LogicalLoraChannelHelper::GetAggregatedWaitingTime()
{
    // Aggregate waiting time
    Time aggregatedWaitingTime = m_nextAggregatedTransmissionTime - Simulator::Now();
 
    // Handle case in which waiting time is negative
    aggregatedWaitingTime = Seconds(std::max(aggregatedWaitingTime.GetSeconds(), double(0)));
 
    NS_LOG_DEBUG("Aggregated waiting time: " << aggregatedWaitingTime.GetSeconds());
 
    return aggregatedWaitingTime;
}
 
Time
LogicalLoraChannelHelper::GetWaitingTime(Ptr<LogicalLoraChannel> channel)
{
    NS_LOG_FUNCTION(this << channel);
 
    // SubBand waiting time
    Time subBandWaitingTime =
        GetSubBandFromChannel(channel)->GetNextTransmissionTime() - Simulator::Now();
 
    // Handle case in which waiting time is negative
    subBandWaitingTime = Seconds(std::max(subBandWaitingTime.GetSeconds(), double(0)));
 
    NS_LOG_DEBUG("Waiting time: " << subBandWaitingTime.GetSeconds());
 
    return subBandWaitingTime;
}
 
void
LogicalLoraChannelHelper::AddEvent(Time duration, Ptr<LogicalLoraChannel> channel)
{
    NS_LOG_FUNCTION(this << duration << channel);
 
    Ptr<SubBand> subBand = GetSubBandFromChannel(channel);
 
    double dutyCycle = subBand->GetDutyCycle();
    double timeOnAir = duration.GetSeconds();
 
    // Computation of necessary waiting time on this sub-band
    subBand->SetNextTransmissionTime(Simulator::Now() + Seconds(timeOnAir / dutyCycle - timeOnAir));
 
    // Computation of necessary aggregate waiting time
    m_nextAggregatedTransmissionTime =
        Simulator::Now() + Seconds(timeOnAir / m_aggregatedDutyCycle - timeOnAir);
 
    NS_LOG_DEBUG("Time on air: " << timeOnAir);
    NS_LOG_DEBUG("m_aggregatedDutyCycle: " << m_aggregatedDutyCycle);
    NS_LOG_DEBUG("Current time: " << Simulator::Now().GetSeconds());
    NS_LOG_DEBUG("Next transmission on this sub-band allowed at time: "
                 << (subBand->GetNextTransmissionTime()).GetSeconds());
    NS_LOG_DEBUG("Next aggregated transmission allowed at time "
                 << m_nextAggregatedTransmissionTime.GetSeconds());
}
 
double
LogicalLoraChannelHelper::GetTxPowerForChannel(Ptr<LogicalLoraChannel> logicalChannel)
{
    NS_LOG_FUNCTION_NOARGS();
 
    // Get the maxTxPowerDbm from the SubBand this channel is in
    std::list<Ptr<SubBand>>::iterator it;
    for (it = m_subBandList.begin(); it != m_subBandList.end(); it++)
    {
        // Check whether this channel is in this SubBand
        if ((*it)->BelongsToSubBand(logicalChannel->GetFrequency()))
        {
            return (*it)->GetMaxTxPowerDbm();
        }
    }
    NS_ABORT_MSG("Logical channel doesn't belong to a known SubBand");
 
    return 0;
}
 
void
LogicalLoraChannelHelper::DisableChannel(int index)
{
    NS_LOG_FUNCTION(this << index);
 
    m_channelList.at(index)->DisableForUplink();
}
} // namespace lorawan
} // namespace ns3