Movesense 1.6.2 send_ble_nus_data B/s?

Question

What is B/s which can be achieved with Movesense send_ble_nus with 1.6.2? I assume packet length 20 is optimal. With 50 Hz * 20 B/s = 1000 B/s no loss when listening with Xamarin Forms https://github.com/aritchie/bluetoothle component on Windows 10 and Android 8.1. With 100 Hz * 20 B/s = 2000 B/s some (Window 10 <1 %, Android 8.1 <0.1 %) packets lost. Can 2000 B/s rates be obtained with e.g. MTU changes or with more optimal code?

Answer 1

Movesense sensor supports up to 158 byte MTU and BLE 4.2 Data Length Extension. If the counterpart knows to use large MTU and DLE, the optimal is to fill it all: i.e. putting data in 155 byte packets. Theoretically it is possible to get up to 800kbps speeds, but in practice with mobile it will be less (maybe much less).

With android it is easy to see what connection parameters are negotiated by enabling the "HCI dump" feature from Developer settings and studying the resulting .log file with Wireshark protocol analyzer.