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Spreading factor and link budget

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  • Spreading factor and link budget

    I found https://ieeexplore.ieee.org/ielx7/62...r=8600701&ref= which is a study on doppler effect in LoRa. The (somewhat simplified) conclusion is that a gound-based station will not be able decode SF12 sent from a satellite in an orbit lower than 550km. Since the sprites will be at ~250km, we should use SF11 or lower. Using SF11 instead of SF12 will eat about 3dB of our link budget. Not a big difference, but it is good to know that using SF12 might yield worse results than SF11.
    Last edited by mfalkvidd; 09-04-2019, 06:28 AM.

  • #2
    Hi mfalkvidd,

    It looks to me, that you have a lot of background knowledge about LoRaWan.

    I would be really nice from you, if you can maybe use the Articles section of this forum to give the newbies (like me) a bit of background.

    Gerd

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    • mfalkvidd
      mfalkvidd commented
      Editing a comment
      TTN has lots of great resources for learning about LoRaWAN. I would not come near their quality even if I spent weeks.

  • #3
    mfalkvidd Thank you very much for this. An interesting article. It would be useful to know the spreading factors involved in the 700+km world record:
    https://www.thethingsnetwork.org/art...e-world-record

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    • #4
      The post you linked says the first record (741km) used SF10BW125 which means SF10. The second (766km) used SF11BW125 so SF11. The post also mentions "theoretical maximum 800 km".

      Since these experiments were with balloons, there was little or no Doppler effect.

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      • #5
        Good article. Thanks for sharing.

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