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Comment by kenrick95 | Hacker News Reader

I've read some papers that claims that Bluetooth and Wi-Fi signal does interfere each other. And in my group project, we tried out transferring files from phone to phone via Bluetooth while there is another file transfer going on from laptop to laptop via Wi-Fi; and the result is that the time taken for the Bluetooth transfer to complete is longer than that when there is no Wi-Fi file transfer going on. Well, it may depend on the version of Bluetooth and Wi-Fi frequency used though. (but in my scenario, we're using 2.4GHz Wi-Fi and Bluetooth 4.0)

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Of course they interfere, Bluetooth and Bluetooth LE use the 2.4-2.48 ISM band, and so does WiFi. WiFi has up to 14 overlapping 20MHz channels, and Bluetooth 4.0 has 40 2MHz channels. Though I guess Bluetooth could be clever enough to avoid the channels with interference.

BLE has 3 advertising channels, spaced to try to avoid the WiFi channels. Once a connection is made (probably not relevant for beacons anyway), it uses frequency hopping over the other 37 channels to avoid interference as much as possible.

Yes, they can sometimes use overlapping bands. However Bluetooth tries to minimize that by using FHSS [0].

I've witnessed it first-hand with my last ultrabok (lenovo yoga 13, 2013), which uses a cheap radio (WiFi + Bluetooth) that shares several components, including a narrow USB bus. End-result: I couldn't use a BL mouse because my WiFi would go dial-up slow [1].

Macbooks had that problem too, FWIW [2]. The ONLY solution? Using a 5 GHz Wifi.

[0] https://en.wikipedia.org/wiki/Frequency-hopping_spread_spect... [1] https://forums.lenovo.com/t5/Lenovo-Edge-Yoga-Lavie-Z-Flex/Y... [2] https://discussions.apple.com/thread/6601731

Bluetooth beacons work by advertising only. The BLE advertising bands are at the start of the WiFi band, after the end, and in the middle (between two common WiFi channels). This minimises the likelihood of interference.

They can interfere, but there's so little data transferred that it's not a practical concern.

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