nRF5340 DK Range isssue with higher MTU

RE: nRF5340 DK Range isssue with higher MTU

Susheel Nuguru — Mon, 18 Dec 2023 07:55:44 GMT

[quote user="AKV"]What is the maximum distance without any packet loss with the given power level.[/quote]

I do not think we have done on field range testing with nRF5340, but have done a lot of range testing with its predecessor (nRF52) and some of blogs were created as a result of those tests like this and this. Since the radio of nRF53 has better sensitivity, I am expecting same or better range as compared to nRF52.

[quote user="AKV"]1. We are transmitting every 20 ms only then why is that range is decreasing with connection interval 12.5ms ?[/quote]

You should sniff the packets in air for the connection and see how these transfers are different with different connection parameters. Transmitting every 20ms for only one connection event of length 2.5ms should not be different for 7.5ms or 12.5ms connection interval.

[quote user="AKV"]2. Why is the transmission is failing only to the last connected device?[/quote]

Not sure if I understand this correctly. The transmission is failing in the last connected device?

RE: nRF5340 DK Range isssue with higher MTU

AKV — Fri, 15 Dec 2023 07:50:10 GMT

[quote userid="6207" url="~/f/nordic-q-a/106396/nrf5340-dk-range-isssue-with-higher-mtu/459339"]How do you conclude the range? Is the limit disconnect event or is the limit throughput?[/quote]

What is the maximum distance without any packet loss with the given power level.

We are testing indoors with reduced power level to do the test indoor. And checking the packet error rate log to conclude the range.

We are transmitting 100 bytes in every 20 ms to all three connected devices.

The event length is 2.5 ms, Connection Interval is 7.5 ms and 2MBPS PHY.

When we increased the connection interval to 12.5 ms then the range is decreasing compared to connection interval 7.5ms and we observed that the the last connected device transmission is failing.

1. We are transmitting every 20 ms only then why is that range is decreasing with connection interval 12.5ms ?

2. Why is the transmission is failing only to the last connected device?

RE: nRF5340 DK Range isssue with higher MTU

Susheel Nuguru — Thu, 07 Dec 2023 11:26:39 GMT

[quote user=""]As per the above parameters 2MBPS and Event length 3.75 ms the MTU we can set up to 247 bytes. But its affecting the range.[/quote]

I think you are setting up the connection for your network too tight. With that connection interval and MTU size with that event length, you are leaving too less of a room for packet loss.

Where are you testing this? hopefully outdoors.

What is the supervision timeout for the connections? Is there any connection latency you are using in the initialization of the connection parameters?

How do you conclude the range? Is the limit disconnect event or is the limit throughput?

But I think there is no general fix or solution that can be given for these kind of tests with such tight connection intervals. I think you need to keep on calibrating connection parameters and MTU size to get a good balance of throughput and range.