I am doing a simple over-the-air(WiFi 802.11a) test in a shielded chamber involving one Tx and one Rx (around 5 feet).. I need to find the duty cycle given the length of the payload (in bytes), MCS etc. As far as I understand , duty cycle is time a device spent on channel / total time . I was going through this paper https://www.academia.edu/15142561/Determination_of_the_duty_cycle_of_WLAN_for_realistic_radio_frequency_electromagnetic_field_exposure_assessment Where the paper calculates the theoretical upper limit of duty cycle for a given MCS

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The payload is 1500 bytes Max data rate is 54 Mbps

How is the data 248 micro secs in calculations? I am thinking,it should be 222.22 micro seconds (1500*8/54 micro seconds)

can any one please let me know about it

And If anyone has done such analysis on duty cycles , please do guide me thanks


1 Answer 1


Wifi uses OFDM, which uses symbols that can transport many bytes at once. That means you can't have arbitrary long packets, but always need to use the next multiple of a symbol duration.

  • $\begingroup$ Thanks, Marcus for your comment and clarification $\endgroup$
    – Saira
    Commented Nov 15, 2019 at 16:12
  • $\begingroup$ You're welcome! You don't have to post a "thank you" comment, though – I'll take your upvote instead :) $\endgroup$ Commented Nov 15, 2019 at 17:08

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