Packet loss due to interference in ble.

[Nabeel Ar]

Board: nRF52810

SoftDevice: s112

SDK version: 17.0.2

I've developed a BLE application where nRF52810 as peripheral and nRF52833 as central. The peripheral continuously sends data to the central and mostly operated in a very close range. While testing my application in a crowded environment I'm experiencing data loss ( I suspect it's due to external interference ). I've checked the RSSI then, it is around -45 dBm ( I think the signal strength is good ). How can I overcome the problem?

Thank you in advance.

[Kenneth]

Hello,

Make sure to use maximum output power, and make sure you have got help to tune the antenna for optimal performance, a poorly tuned antenna will reduce the effective output power radiated. If you are using the internal LFCLK (internal RF 32kHz), then make sure you have set the tolerance to 500ppm and that the LFCLK callibrate the RC oscillator. This should ensure that you have a good design with good output power and that the peripheral tolerate timing drift between the two peers.

You can also consider to use shorter connection interval, this will allow more time to send data.

Best regards,
Kenneth

[Nabeel Ar]

Hi Kenneth,

I'm already using maximum tx power (4 dBm) and the tolerance is 500ppm. The connection interval is 7.5ms (min) and 15 ms (max), which I think is a shorter connection interval. Though I'm getting data loss due to interference.

Does Channel Hopping has to do anything to make it efficient? Will QoS or Adaptive channel hopping help me to overcome the problem??

Thanks in advance.

[Kenneth]

Nabeel Ar said:

Does Channel Hopping has to do anything to make it efficient? Will QoS or Adaptive channel hopping help me to overcome the problem??

No, this is simply a matter of link budget and signal level of the interference. So you need to improve the link budget by optimizing the design (e.g. make sure the antenna is properly tuned to 50ohm in the final product casing and tune the output power to 4dBm, adding a PA on the front-end will help (e.g. n21540)). Other than that it's very little one can do).

Kenneth

[Nabeel Ar]

Hi,

Kenneth said:

So you need to improve the link budget by optimizing the design (e.g. make sure the antenna is properly tuned to 50ohm in the final product casing

I'm already using 3rd party module with an antenna designed with the configuration mentioned above. Can anything be done on the firmware side to overcome the issue?

[Kenneth]

I would say no, but you can double check with the module manufacturer that you have placed the module according to their recommendations.

Kenneth