Advertisement packet loss in Coded PHY vs 1 Mb PHY

[Kcecil]

Using the following:

Rigado BMD-360 nRF52811 development board.

Softdevice S140 7.0.1

SDK 16.0

Using two development boards inches apart, one development board sends a single advertising event every 12 seconds.  The other development board is continuously scanning (interval and window = 7s).  The packets have 30 bytes of data including a sequence number.  I calculated packet loss based on the missing sequence numbers.

Sending and scanning using the 1 MB/s PHY, in a test of approx. 20 minutes  I get 100% reception of packets.

Sending and scanning using the Coded PHY, in the same test I get ~43% reception of packets, ~57% packet loss.

Is this expected behavior, or could I be configuring something wrong when advertising using Coded PHY?

Another behavior I've seen is for the above condition using the Coded PHY to have a repeating pattern of receiving 3 and missing 2.

[Simonr]

Could you provide any details as to how you confirmed the packets were lost on air? You could also try using SPI for transmission on the DK as well, just to make sure that it provides the same output as the UART.

If it is indeed on the air I think I'll have to see your hardware files to make sure the antenna matching, etc. all look good. Please let me know if you'd like me to set this case to private before you share any files and I'll do so.

Please note that we're entering the summer vacation period here in Norway, so delays must be expected as we are low on staff for the month of July. Sorry about the inconvenience!

Best regards,

Simon

[Kcecil]

Simon,

To verify the packets were lost on air, I simultaneously debugged the BLE application through SWD printing what was received, and monitored the output from the host processor.  When the host processor showed a missing packet, the debugger output also showed a missing packet.

Delays are not an issue at this point.  I don't see using a shorter scan interval as an issue, although I am curious as to why it would make a difference.