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Last active April 23, 2020 09:11
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BLE advertisement frame successful exchange rate in scenarios with many advertising devices
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ble_frame_collisions.md

This is based on my partial knowledge of radio networks, and on very incomplete knowledge of the BLE stack.

AFAIK BLE scans in short intervals on one of 3 channels. With >50 devices in advertisement mode it may be hard to get non-colliding frames to the receiver.

  • I don’t think Bluetooth LE was designed to have hundreds of devices in discoverable mode sending out garbage identity frames.
  • Increasing the radio wake time may not be a solution either because you end up with flat batteries too quickly.

Protocol

  • 3 advertising channels;
  • scanning device listens to one for the discovery window(?);
  • advertising device hops to 1-3(?) and broadcasts the advertisment frame.

References

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