S130 and scan performance potential issue

[Fabien Comte]

Hello,

I use S130 with NUS style connections as central and device at same time. It works nice and performance is good but when i run scan, performance become very poor.

I need active scan to see any iBeacon in proximity area and / or any new potential device.

Is there any way to fix that ? Fast "passive" scan at same time that fast connections ?

edit:

Performance is a "ping" latency (question from nRF51 board A to nRF51 board B then response from B to A)

define MIN_CONNECTION_INTERVAL (1 * BLE_GAP_CP_MIN_CONN_INTVL_MIN)

define MAX_CONNECTION_INTERVAL (1 * BLE_GAP_CP_MIN_CONN_INTVL_MIN)

define SLAVE_LATENCY 0

define SUPERVISION_TIMEOUT MSEC_TO_UNITS(1000, UNIT_10_MS)

define SCAN_INTERVAL MSEC_TO_UNITS(10, UNIT_0_625_MS)

define SCAN_WINDOW MSEC_TO_UNITS(5, UNIT_0_625_MS)

=> 20 to 30 ms (10 ms resolution)

define MIN_CONNECTION_INTERVAL (1 * BLE_GAP_CP_MIN_CONN_INTVL_MIN)

define MAX_CONNECTION_INTERVAL (1 * BLE_GAP_CP_MIN_CONN_INTVL_MIN)

define SLAVE_LATENCY 0

define SUPERVISION_TIMEOUT MSEC_TO_UNITS(1000, UNIT_10_MS)

define SCAN_INTERVAL MSEC_TO_UNITS(10, UNIT_0_625_MS)

define SCAN_WINDOW MSEC_TO_UNITS(10, UNIT_0_625_MS)

=> 200 ms (10 ms resolution)

Thank you.

[Petter Myhre]

You only have one radio. It can either scan or handle a connection event. By setting the scan window equal to the scan interval you tell the SoftDevice to scan 100 % of the time, and more connection events will be dropped. You can read more about this in the S130 SoftDevice Specification, see this. I'm not sure what connection interval you are actually using, but I recommend you to try different settings and see if you can get results that fulfill your requirements.

[Fabien Comte]

I understand if scanning share the same radio frontend you can just work on a channel at a time. But is there any way to do a kind of passive scan (use the channels sequences of connections) because emiters will transmit on the 3 bands in this case and i will increase my probability ?