34 lines
950 B
C++
34 lines
950 B
C++
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#include "transmission.hpp"
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#include <chrono>
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namespace vanetza
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{
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namespace dcc
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{
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Clock::duration Transmission::channel_occupancy() const
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{
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using namespace std::chrono;
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// assume 6 Mbps as default data rate
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const access::DataRateG5* rate = data_rate() ? data_rate() : &access::G5_6Mbps;
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// PHY
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static const auto phy_preamble = microseconds(32);
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static const auto phy_signal = microseconds(8);
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// MAC
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static const std::size_t bytes_epd = 2; // EtherType Protocol Discrimination (no LLC!)
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static const std::size_t bytes_mac = 34; // 802.11 MAC header
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const std::size_t bytes = rate->data_length(body_length() + bytes_epd + bytes_mac);
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const double seconds_per_byte = 1.0 / (rate->bytes_per_second());
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const duration<double> data_duration { bytes * seconds_per_byte };
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return phy_preamble + phy_signal + duration_cast<microseconds>(data_duration);
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}
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} // namespace dcc
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} // namespace vanetza
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