android Android-nRF-UART app connection interval/bandwidth configuration

[Vala]

Hi,

I hope is not a double post. I am doing a throughput evaluation with my custom board and an app that is based on the Nordic's Android UART app through NUS service and wanted to make sure that this app is capable of handling the requirements for a fast data transfer: connection interval, bandwidth connection event extension. Please let me know if there are other parameters that matters.

Vala

Edit: I guess the bandwidth, which defines the number of packets per connection interval, is basically defined and restricted by the Android OS. Am I right?

[Hung Bui]

Hi Vala,

On nRF5 side, beside connection interval, bandwidth connection event extension, how quick you send your data is also important to improve bandwidth. You should send as many packet as possible on a single connection event. Usually the approach is to queue until the buffer is full and queue again when there is packet sent (TX_COMPLETE event). It's better to send a packet with 20 bytes payload than sending several small payload packets.

On the Android side, you can also try to use .requestConnectionPriority() to request high priority for the connection. The "number of packets per connection event" is limited by the hardware on the device, what is important is to utilize the maximum the hardware can handle.

[Vala]

One question, is bandwidth in this context a SIG defined term? Or it is related to the SoftDevice definitions? I want to know if for example in Android devices (or other non-Nordic devices) there is a therm called bandwidth, which means "the allowed number of packets per connection interval"?