Slow rate from central to peripheral

Question

Hello,

I'm working on nrF52832 with two different Android device : Samsung Galaxy note 3 neo and HTC ONE M8.

My test :

Central side ( smartphone ) : each 200 ms I send 20 Bytes during 20s -> 100 * 20 Bytes
Peripheral side : I measure the time between the first packet and the last one.

The result :

HTC ONE M8 : 20.2 s to receive data
SAMSUNG = 43 s to receive data

We are trying to improve the data transmission because the rate is too slow on some smartphone ( ex : samsung note 3 neo ).

I think that the connection interval on ble_evt_connected return 39 -> 48,5ms ( for both smartphone )

#define MIN_CONN_INTERVAL                MSEC_TO_UNITS(10, UNIT_1_25_MS)           /**< Minimum acceptable connection interval (0.1 seconds). */
#define MAX_CONN_INTERVAL                MSEC_TO_UNITS(200, UNIT_1_25_MS)           /**< Maximum acceptable connection interval (0.2 second). 200*/
#define SLAVE_LATENCY                    0                                          /**< Slave latency. */
#define CONN_SUP_TIMEOUT                 MSEC_TO_UNITS(4000, UNIT_10_MS)            /**< Connection supervisory timeout (4 seconds). */

How can I increase the speed ?

Thank you very much.

Nabil

endnode · Accepted Answer

(get a sniffer, get a sniffer, get a sniffer... that's all I can recommend to you right now)

run_ar · Answer

Also try sending a connection parameter update request asking for max of 20. Or maybe as low of 7.5. The central dictates the conection interval and might not accept this. Setting max and min to 200ms - 7.5ms means the peripheral will accept any parameter within this range.

Slow rate from central to peripheral

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