BLE transmission data loss from 5 peripherals to 1 central device

[masterLee]

Hi,

I have a configuration of five nRF52840 custom devices transmitting sensor data to a central device (laptop)

The devices can be connected and send data to the central but the central very frequently loses data

coming from the peripherals. This occurs randomly between peripherals during one connection session meaning that data

loss is noticed for example in peripheral 1 and 3 and after lets say two minutes in peripherals 2 and 5.

By saying data loss I mean that in a series of 100 data packets I notice approximately 10 lost packets from a peripheral.

The data loss is verified by the timestamp that is attached in each peripheral packet that is transmitted

Also, when I tried to connect the central to one peripheral device instead of 5 the all packets are transmitted without issues

Any ideas why this can happen?

Thank you for your time

[Kenneth]

The connection event length extension will have no effect in this case, it will only adjust the amount of time that should be allocated locally,  it will have no effect on the peer (phone).

Kenneth

[masterLee]

Thanks!

One last question.

In theory, for one peripheral the LE data packet transmission time (@2Mbps) is 1.4msec. Let's say 2msec for convenience. So for five devices the Connection Interval should be minimum 10 msec.

In a previous post, you suggested me to set minimum and maximum interval to 20msec, and gap event length to 3. Would it be wrong to make the connection interval somewhere closer to 10 msec?

It is not a problem for me to set it to 20msec I just want to understand the reason you suggested 20 msec in case I think of something the wrong way

Thank you for your time!