Two nRF52832DK boards on a table, approx 20 cm from each other, +4dBm output power.
Payload length is ~60bytes.
Running at 1Mbps gives me less than 0.1% PER, running at 2Mbps gives about 25% PER. (everything else kept identical)
Is this expected, or is there something at play here?
Could be how you are doing the PER measurement? Which code are you using?
Also, could just be local WiFi traffic stomping on the Bluetooth signals. The narrow 1Mbps signals sit pretty well in between wifi channels but not so with 2Mbps signals.
Try moving all the wifi stuff far away or turning them off. Also make sure you don't have a smartphone/tablet with you.
Nope, no WiFi or anything else... Spectrum is almost empty here... the same difference regardless of what channel I'm using....
And at that distance, if anything would affect the reception to a large extent it would probably be receiver saturation in that case.... But it that case, why such a difference between 1Mbps and 2Mbps...
BLE is FSK so IMD in the receiver shouldn't be an issue. What software are you using to measure PER?
Also is highly dependent on how you load the channel, hence the software question. The raw rate is 2Mbps but does not include all the BLE overhead. So actual rate is less. If you just try to shove 2Mbps through the pipe you will always see a high packet loss due to the overhead.
Here is some more info on the expected throughput:
Expected throughput is irrelevant in this topic... This has simply nothing to do with throughput at all actually...
I donated know what's confusing with the question... And where did BLE overhead come in to the question?
Let me clarify the question again so that we please could leave throughput and BLE overhead out of it since it's irrelevant... I'm not even using the soft device... And throughput and packet error rate is two completely different things, even though PER can influence the throughput...