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QMesh: A LoRa-based Voice Mesh Network

Developing a synchronized, flooded mesh network to carry codec2-encoded voice over LoRa

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The goal is to develop a functional replacement for FM voice in amateur radio that allows every device to function as a repeater. A simple synchronized, flooded mesh network will be used to forward codec2-encoded voice frames between devices. LoRa's resistance to interference will be leveraged to allow the network to withstand the large number of collisions that occur when using a flooded mesh, thus minimizing the broadcast storm problem.

Please see the GitHub Wiki for up-to-date information about QMesh.

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  • 1 × Custom LoRa RF shield
  • 1 × STM32 NUCLEO-144 board
  • 1 × Antenna SMA-male antenna for the right frequency (433MHz, 915MHz, etc.)
  • 1 × USB power supply Need to supply at least 1A
  • 1 × Amateur radio license Technician or higher in the United States to use this semi-custom, experimental RF hardware setup.

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  • Testing Results

    Dan Fay03/06/2020 at 03:25 0 comments

    It looks like the basic principle of QMesh -- that a synchronized, flooded mesh network can achieve a decently-high packet receive rate via the capture effect -- is valid.

    If I place two relay nodes right next to each other, I can get a packet receive rate (PRR) of around 80-100% when the received signals are strong. For marginal signal strengths, the collisions seem to effectively raise the noise floor.

  • Testing Capture

    Dan Fay02/19/2020 at 14:50 0 comments

    Basic meshing (i.e., data relaying) is working. Getting receive working was somewhat challenging due to some SPI bus contention issues as well as some CPU usage issues.

    This weekend will hopefully be the time when we determine whether successful capture works!

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  • 1
    Pending

    Once the hardware design stabilizes, I'll have better information here. Right now, however, I'm rapidly changing the design of the RF shield.

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Discussions

Per-Oskar O wrote 03/21/2020 at 12:08 point

Congratulations to the successful experiment. Do you think it would be possible to use this to make a lora based walkie talkie? I've been looking into the possibility make a cheap and dirty walkie-talkie using a esp32 and ESPnow. But alas, neither my codingskills nor my electronicsskills are good enough for that project. 

  Are you sure? yes | no

Dan Fay wrote 07/17/2019 at 12:17 point

Yes, there definitely has been! Please see the project's Github page (https://github.com/faydr/QMesh) for updates.

  Are you sure? yes | no

Dave wrote 05/28/2019 at 21:18 point

Any progress to report on this effort?  Interested.

  Are you sure? yes | no

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