How does BLE/WiFi-Coexistence in the ESP32 work?

michaelwgnr
Posts: 26
Joined: Wed Dec 21, 2016 3:41 pm

How does BLE/WiFi-Coexistence in the ESP32 work?

Postby michaelwgnr » Thu Mar 16, 2017 2:52 pm

A very general question: A BLE peripheral has hard timing constraints and is required to receive and transmit during its short connection events. From my understanding, I would assume both technologies use the same radio peripheral in the ESP32-hardware and access to the peripheral would be governed by some sort of TDMA-scheme. Is this assumption correct?

What effect does this have on the coexistence of WiFi on the ESP32? How is that problem of the radio being occuppied by BLE or WiFi solved? :?:

madscientist_42
Posts: 95
Joined: Tue Feb 21, 2017 10:17 pm

Re: How does BLE/WiFi-Coexistence in the ESP32 work?

Postby madscientist_42 » Thu Mar 16, 2017 5:51 pm

michaelwgnr wrote:A very general question: A BLE peripheral has hard timing constraints and is required to receive and transmit during its short connection events. From my understanding, I would assume both technologies use the same radio peripheral in the ESP32-hardware and access to the peripheral would be governed by some sort of TDMA-scheme. Is this assumption correct?

What effect does this have on the coexistence of WiFi on the ESP32? How is that problem of the radio being occuppied by BLE or WiFi solved? :?:
The RF Front-end (RFE) might be the same, but unlikely so. They've got differing power profile requirements and BANDWIDTH requirements.

Bluetooth has a 1MHz channel allocation.
BLE has a 2MHz channel allocation.
802.11n has a 20-40MHz channel allocation.

That's just the beginning.

If they don't share the same RFE with adjustments on modulation, etc. they will have two separate radios that run in COEX mode. Part of that Coexistence behavior is in Bluetooth's adaptive hopping system for the receive subsystem. The other part is a bunch of handshaking lines between the two radios to synchronize the transmissions on both modems so they're not transmitting at the same time.

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