what is the relation between connection interval and the throughput?

[ahmed fathy]

i am using nrf52840 DK with softdevice (s140_nrf52840_5.0.0-1.alpha_softdevice) and applying this throughput example ATT_MTU Throughput Example. 
and notice that when I use MTU = 247 and the connection interval = 400 ms. the throughput is higher than using 7.5 ms and as I understand the packets per connection interval is limited to 6 packets so no need to make the connection interval higher than 7.5 ms if we need the highest throughput so I can't understand why throughput is higher at connection interval 400 ms than 7.5 ms?!! 

[ovrebekk]

Hi 

When using nRF devices on both sides of the link there is no limitation to how many packets you can send in a single connection event, and as such there is no need to minimize the connection interval to increase throughput. 

In fact, using very short connection intervals will reduce throughput, since there is some idle time at the end of every connection event where you will not be able to send any data. This idle time is more or less the same regardless of connection interval, so when using a longer interval it will have less impact on the throughput. 

The exception to this rule is in situations where the link is poor and you experience a lot of packet loss. Then longer connection intervals can reduce the throughput, since the connection event stops as soon as a packet is dropped. 

Best regards
Torbjørn 

[ahmed fathy]

thank you 

[ovrebekk]

You welcome