nRF52833 advertising packet missing while in scanning Mode.

RE: nRF52833 advertising packet missing while in scanning Mode.

bjorn-spockeli — Wed, 22 Jan 2020 08:46:37 GMT

You can make sure thatthe central is scanning all the time, i.e. Scan windon == Scan Interval. Other than that its the RF environment that dictates how often a packet collision occurs. So make sure that there are as little 2.4GHz interference as possible in the area where you are deploying your tags.

Best regards

Bjørn

RE: nRF52833 advertising packet missing while in scanning Mode.

Swapnil Karkare — Wed, 22 Jan 2020 08:42:47 GMT

Hi Bjørn,

Do you have any suggestion regarding how to minimize packet losses?

Best Regards,

Swapnil

RE: nRF52833 advertising packet missing while in scanning Mode.

bjorn-spockeli — Wed, 22 Jan 2020 07:53:04 GMT

[quote user="Swapnil_karkare"][/quote]

I do apologize, but i didn't get the last line

"then you need to be in a connection where the link layer ensures that lost packets are retransmitted. "

Is this mean central needs to connected with peripheral? or could you give us more information regarding this?

Yes, that is what I meant. In order to guarantee that all packets sent by the peripheral is received by the central, then the peripheral and central must be connected. If the peripheral is only advertising and the central is scanning, then there will be packets lost either due to packet collisions or the central switching between the advertisement channels.

[quote user="Swapnil_karkare"][/quote]

In Our case all tags are non connectable and we need to scan only adverting packet of our pro priority tags. The nos could go up to 100 tags per 10 seconds.

For packet missing testing i am searching for only fixed tag with comparing MAC Addr and print timings.

In this scenario you will have to accept missing packets due to packet collisions or the central switching between the advertisement channels.

Best regards

Bjørn

RE: nRF52833 advertising packet missing while in scanning Mode.

Swapnil Karkare — Wed, 22 Jan 2020 07:33:51 GMT

Hi Bjørn,

I do apologize, but i didn't get the last line

"then you need to be in a connection where the link layer ensures that lost packets are retransmitted. "

Is this mean central needs to connected with peripheral? or could you give us more information regarding this?

In Our case all tags are non connectable and we need to scan only adverting packet of our pro priority tags. The nos could go up to 100 tags per 10 seconds.

For packet missing testing i am searching for only fixed tag with comparing MAC Addr and print timings.

RE: nRF52833 advertising packet missing while in scanning Mode.

bjorn-spockeli — Tue, 21 Jan 2020 14:08:37 GMT

Hi Swapnil,

Even if your central is scanning all the time, i.e. Scan windon == Scan Interval, you will still have a short period when the RADIO is switching scan frequency where you cannot receive any packets. In addition there might be packet collisions, interference etc that causes a packet to be discarded. Hence, if you need the data to arrive reliably, then you need to be in a connection where the link layer ensures that lost packets are retransmitted.

Best regards

Bjørn