I need help developing a gateway.

[HakJae]

Hi. I am developing a gateway using SDK15 and nRF52840.

I'm advertising 4 devices every 20ms.

Theoretically, it should be scanned 50 times each, but in reality it is scanned from 6 to 12.

At this time, the gateway is set up as follows.

/** @brief Parameters used when scanning. */
static ble_gap_scan_params_t const m_scan_params =
{
.active = 0,
.interval = SCAN_INTERVAL,         // 0xa0
.window = SCAN_WINDOW,          // 0xa0
.timeout = SCAN_DURATION,       // 0x00
.scan_phys = BLE_GAP_PHY_1MBPS,
.filter_policy = BLE_GAP_SCAN_FP_ACCEPT_ALL,
};

Please help me.

[David Edwin]

I ran a simulator test for 4 nodes to gateway, it appears that each node needs to transmit a packet about 5 times (worst case) before it is detected. This means your assumption of gateway detecting 50 packets of each node is optimistic.  

Improvements possible:

Use passive scanning in the gateway and non-connectable advertising in the nodes, this should improve the scanner performance a bit.