83 lines
2.5 KiB
C++
83 lines
2.5 KiB
C++
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#include "duty_cycle_permit.hpp"
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#include "limeric_budget.hpp"
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#include <vanetza/common/runtime.hpp>
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#include <chrono>
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#include <cmath>
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namespace vanetza
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{
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namespace dcc
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{
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namespace
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{
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constexpr Clock::duration min_interval = std::chrono::milliseconds(25);
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constexpr Clock::duration max_interval = std::chrono::seconds(1);
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} // namespace
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LimericBudget::LimericBudget(const DutyCyclePermit& dcp, const Runtime& rt) :
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m_duty_cycle_permit(dcp), m_runtime(rt),
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m_interval(min_interval), m_tx_start(Clock::time_point::min()),
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m_tx_on(Clock::duration::zero())
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{
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update();
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}
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Clock::duration LimericBudget::delay()
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{
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Clock::duration delay = Clock::duration::max();
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if (m_runtime.now() >= m_tx_start + m_interval) {
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delay = Clock::duration::zero();
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} else {
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delay = m_tx_start + m_interval - m_runtime.now();
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}
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return delay;
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}
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Clock::duration LimericBudget::interval()
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{
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return m_interval;
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}
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void LimericBudget::notify(Clock::duration tx_on)
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{
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m_tx_start = m_runtime.now();
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m_tx_on = tx_on;
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using std::chrono::duration_cast;
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const auto duty_cycle = m_duty_cycle_permit.permitted_duty_cycle();
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const auto interval = duration_cast<Clock::duration>(tx_on / duty_cycle.value());
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m_interval = clamp_interval(interval);
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}
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void LimericBudget::update()
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{
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using std::chrono::duration_cast;
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using FloatingPointDuration = std::chrono::duration<double, Clock::period>;
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const FloatingPointDuration delay = m_tx_start + m_interval - m_runtime.now();
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const double duty_cycle = m_duty_cycle_permit.permitted_duty_cycle().value();
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if (duty_cycle > 0.0) {
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if (delay.count() > 0.0) {
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// Apply equation B.2 of TS 102 687 v1.2.1 if gate is closed at the moment
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const FloatingPointDuration interval = (m_tx_on / duty_cycle) * (delay / m_interval);
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m_interval = clamp_interval(duration_cast<Clock::duration>(interval) + m_runtime.now() - m_tx_start);
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} else {
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// use equation B.1 otherwise
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const FloatingPointDuration interval = m_tx_on / duty_cycle;
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m_interval = clamp_interval(duration_cast<Clock::duration>(interval));
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}
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} else {
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// bail out with maximum interval if duty cycle is not positive
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m_interval = max_interval;
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}
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}
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Clock::duration LimericBudget::clamp_interval(Clock::duration interval) const
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{
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return std::min(std::max(interval, min_interval), max_interval);
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}
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} // namespace dcc
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} // namespace vanetza
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