S130 and scan performance potential issue

Question

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 · Accepted Answer

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.