Bluetooth / WiFi interference

Hi,

When running a bluetooth scan, we noticed that WiFi speeds drop dramatically on 2.4Ghz. Moreover, we see a very large jitter, where sometimes not a single packet gets through for about 3 seconds. The results with 5Ghz WiFi are much better. There, we also see a drop in speed, but it’s more in line with what we would expect.

The table below indicates whether a bluetooth scan was running, wether the duplicate-data parameter was enabled and what type of WiFi we were on:

Is this a known issue and is there any way to tune or fix this?

Thanks!
Niels Avonds

I think it is kind of interference of BT’s 2.4G with the Wifi. Have you tried to changed the band of wifi channel?

Thanks for the response.

Even if it only happens in a few bands, this is still an issue for us. We will be installing in a consumer setting where we do not control the WiFi network. Especially the 3 second delay where nothing get through is very worrying. Do you have any statistics on what the expected drop in speed is?

In our development environment we work around this by using 5GHz, but we will be rolling out to customers soon where we have no control over the WiFi network settings.

Hi,

Unfortunately, if this is signal strength or noise interference issue, we cannot resolve it by some software configuration.

Bluetooth and 2.4GHz wifi share the same antenna, so there will be an impact when Bluetooth and wifi are active.

There other variables here are

  • Other 2.4GHz noise, Microwave, other access points & Bluetooth activity
  • Other wifi traffic on the local network
  • Direct attached network devices
  • Quality of the access point, from a traffic routing perspective
  • Network congestion at the server used for through put test’s

These are the only variable that you could control. If the bcm4354 module cannot achieve your goal, please find other wifi module from other vendors on your product.

Which jetpack release are you using?

We do expect some interference, but what worries me most is the large delays when trying to ping (up to almost 3 seconds). I would expect the average speed to drop but these delays make the WiFi connection unusable.

As for Jetpack, we used the latest version available at the time of our test: Jetpack 4.3.

Hi,

Since BT and Wifi 2.4 GHz operate in TDM, interference is expected. BT scan is special case where BT occupies most of the air time and result is not surprising.

Make a conclusion here, this issue is not avoidable unless you use other channels that have less interference or noise.

We will not and cannot provide any other software solution for this issue. As my previous suggestion, if this wifi chip cannot satisfy your product, please use wifi/bt chip from other vendors. It is very common for other customers’ case too.