samples: Bluetooth: add concurrent scanner and initiator sample

Add sample application that demonstrates faster connection
establishment using CONFIG_BT_SCAN_AND_INITIATE_IN_PARALLEL.

Signed-off-by: Henrik Lander <[email protected]>

samples/bluetooth/scanning_while_connecting/CMakeLists.txt

@@ -0,0 +1,11 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(connection_establishment_benchmark)
+
+target_sources(app PRIVATE src/main.c)

samples/bluetooth/scanning_while_connecting/Kconfig.sysbuild

@@ -0,0 +1,10 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+source "${ZEPHYR_BASE}/share/sysbuild/Kconfig"
+
+config NRF_DEFAULT_IPC_RADIO
+	default y

samples/bluetooth/scanning_while_connecting/README.rst

@@ -0,0 +1,228 @@
+.. _bt_scanning_while_connecting:
+
+Bluetooth: Scanning while connecting
+####################################
+
+.. contents::
+   :local:
+   :depth: 2
+
+The sample demonstrates how to reduce the time to establish connections to many devices, typically done when provisioning devices to a network.
+The total connection establishment time is reduced by scanning while connecting and by using the filter accept list.
+
+Requirements
+************
+
+The sample supports the following development kits:
+
+.. table-from-sample-yaml::
+
+The sample also requires at least one other development kit.
+Out of the box, this sample can be used together with the :ref:`peripheral_with_multiple_identities`.
+This sample filters out devices with a different name than a device running the :ref:`peripheral_with_multiple_identities` sample.
+The :ref:`peripheral_with_multiple_identities` sample acts as multiple peripheral devices.
+
+Overview
+********
+
+You can use this sample as a starting point to implement an application designed to provision a network of Bluetooth peripherals.
+The approaches demonstrated in this sample will reduce the total time to connect to many devices.
+A typical use-case is a gateway in a network of devices using Periodic Advertising with Responses.
+
+To illustrate how connection establishment speed can be improved, it measures the time needed to connect to 16 devices with three different modes: sequential scanning and connection establishment, concurrent scanning while connecting, and concurrent scanning while connecting with the filter accept list.
+
+Sequential scanning and connection establishment
+================================================
+
+This is the slowest and simplest approach.
+Sequential scanning and connection establishment is recommended when the application only needs to connect a handful of devices.
+
+The message sequence chart below illustrates the sequence of events.
+After a device is discovered, the application stops scanning and attempts to connect to the device.
+Once the connection is established, the application starts the scanner again to discover other connectable devices.
+
+.. msc::
+    hscale = "1.3";
+    App, Stack, Peers;
+    App=>Stack [label="scan_start()"];
+    Peers=>Stack [label="ADV_IND(A)"];
+    Stack=>App [label="scan_recv(A)"];
+    App=>Stack [label="scan_stop()"];
+    App=>Stack [label="bt_conn_le_create(A)"];
+    Peers=>Stack [label="ADV_IND(A)"];
+    Stack=>Peers [label="CONNECT_IND(A)"];
+    Stack=>App [label="connected_cb(A)"];
+    App=>Stack [label="scan_start()"];
+    Peers=>Stack [label="ADV_IND(B)"];
+    Stack=>App [label="scan_recv(B)"];
+    App=>Stack [label="scan_stop()"];
+    App=>Stack [label="bt_conn_le_create(B)"];
+    Peers=>Stack [label="ADV_IND(B)"];
+    Stack=>Peers [label="CONNECT_IND(B)"];
+    Stack=>App [label="connected_cb(B)"];
+
+Concurrent scanning while connecting
+====================================
+
+This mode requires the application to enable the :kconfig:option:`CONFIG_BT_SCAN_AND_INITIATE_IN_PARALLEL` Kconfig option.
+In this mode, the scanner is not stopped when the application creates connections.
+During a connection establishment procedure to a device, the application caches other devices it also wants to connect to.
+Once the connection establishment procedure is complete, it can immediately initiate a new connection establishment procedure to the cached device.
+When connecting to a cached device, the connection establishment procedure takes one less advertising interval compared to the sequential scanning and connection establishment mode.
+
+.. msc::
+    hscale = "1.3";
+    App, Stack, Peers;
+    App=>Stack [label="scan_start()"];
+    Peers=>Stack [label="ADV_IND(A)"];
+    Stack=>App [label="scan_recv(A)"];
+    App=>Stack [label="bt_conn_le_create(A)"];
+    Peers=>Stack [label="ADV_IND(B)"];
+    App rbox App [label="Cache address B"];
+    Peers=>Stack [label="ADV_IND(A)"];
+    Stack=>Peers [label="CONNECT_IND(A)"];
+    Stack=>App [label="connected_cb(A)"];
+    App=>Stack [label="bt_conn_le_create(B)"];
+    Peers=>Stack [label="ADV_IND(B)"];
+    Stack=>Peers [label="CONNECT_IND(B)"];
+    Stack=>App [label="connected_cb(B)"];
+
+Concurrent scanning while connecting with the filter accept list
+================================================================
+
+This mode requires the application to enable the :kconfig:option:`CONFIG_BT_FILTER_ACCEPT_LIST` Kconfig option in addition to :kconfig:option:`CONFIG_BT_SCAN_AND_INITIATE_IN_PARALLEL`.
+When the application starts the connection establishment procedure with the filter accept list, it can connect to any of the previously cached devices.
+This reduces the total connection setup time even more, because connection establishment is not relying on the on-air presence of only one of the cached devices.
+
+.. msc::
+    hscale = "1.3";
+    App, Stack, Peers;
+    App=>Stack [label="scan_start()"];
+    Peers=>Stack [label="ADV_IND(A)"];
+    Stack=>App [label="scan_recv(A)"];
+    App=>Stack [label="bt_conn_le_create(A)"];
+    Peers=>Stack [label="ADV_IND(B)"];
+    Peers=>Stack [label="ADV_IND(C)"];
+    Peers=>Stack [label="ADV_IND(D)"];
+    App rbox App [label="Cache addresses B, C, D"];
+    Peers=>Stack [label="ADV_IND(A)"];
+    Stack=>Peers [label="CONNECT_IND(A)"];
+    Stack=>App [label="connected_cb(A)"];
+    App rbox App [label="Set filter accept list to\nB, C, D"];
+    App=>Stack [label="bt_conn_le_create_auto()"];
+    Stack rbox Stack [label="The stack will connect to the first present ADV_IND of\nthe peers B,C,D"];
+    Peers=>Stack [label="ADV_IND(C)"];
+    Stack=>Peers [label="CONNECT_IND(C)"];
+    Stack=>App [label="connected_cb(C)"];
+
+.. note::
+   This sample application assumes it will never have to cache more devices than the maximum number of addresses that can be stored in the filter accept list.
+   For applications that cannot adhere to this simplification, the function :cfunc:`cache_peer_address` can be changed to not store more than defined by the :kconfig:option:`CONFIG_BT_CTLR_FAL_SIZE` Kconfig option.
+   Another simplification done in the sample application is storing duplicate devices in the filter accept list.
+
+Configuration
+*************
+
+|config|
+
+Building and running
+********************
+
+.. |sample path| replace:: :file:`samples/bluetooth/scanning_while_connecting`
+
+.. include:: /includes/build_and_run.txt
+
+Testing
+=======
+
+|test_sample|
+
+1. |connect_kit|
+#. |connect_terminal|
+#. Observe that the sample connects and prints out how much time it takes to connect to all peripherals.
+
+Sample output
+=============
+
+The result should look similar to the following output::
+
+   *** Booting nRF Connect SDK v2.8.99-1c63490f0539 ***
+   *** Using Zephyr OS v3.7.99-b9bc0846b926 ***
+   I: SoftDevice Controller build revision:
+   I: 49 40 e2 c0 6b e5 0d b3 |[email protected]...
+   I: ba a6 48 5e 49 a6 95 3d |..H^I..=
+   I: 65 35 b6 7c             |e5.|
+   I: HW Platform: Nordic Semiconductor (0x0002)
+   I: HW Variant: nRF54Lx (0x0005)
+   I: Firmware: Standard Bluetooth controller (0x00) Version 73.57920 Build 233139136
+   I: Identity: F6:BF:24:7D:46:5D (random)
+   I: HCI: version 6.0 (0x0e) revision 0x3030, manufacturer 0x0059
+   I: LMP: version 6.0 (0x0e) subver 0x3030
+   I: Bluetooth initialized
+
+   I: SEQUENTIAL_SCAN_AND_CONNECT:
+   I: starting sample benchmark
+   I: Connected to FF:AB:68:0C:34:FD (random), number of connections 1
+   I: Connected to E2:12:BF:D3:FB:D5 (random), number of connections 2
+   I: Connected to EE:37:AA:62:A2:FB (random), number of connections 3
+   I: Connected to C7:9B:42:1B:48:F8 (random), number of connections 4
+   I: Connected to F0:27:5B:37:0F:4B (random), number of connections 5
+   I: Connected to C8:BA:1D:6F:95:2B (random), number of connections 6
+   I: Connected to DF:02:31:C3:0B:C2 (random), number of connections 7
+   I: Connected to C7:E1:60:7A:F1:E0 (random), number of connections 8
+   I: Connected to CA:89:50:33:AB:31 (random), number of connections 9
+   I: Connected to E9:47:6B:FA:2F:DE (random), number of connections 10
+   I: Connected to EF:92:DC:88:3B:B3 (random), number of connections 11
+   I: Connected to F4:9C:8C:24:F9:44 (random), number of connections 12
+   I: Connected to DD:84:44:64:5D:FB (random), number of connections 13
+   I: Connected to FB:92:1D:8E:8C:D8 (random), number of connections 14
+   I: Connected to D9:E5:51:E0:5E:24 (random), number of connections 15
+   I: Connected to CF:2F:99:89:A3:4D (random), number of connections 16
+   I: 12 seconds to create 16 connections
+   I: Disconnecting connections...
+   I: ---------------------------------------------------------------------
+   I: ---------------------------------------------------------------------
+   I: CONCURRENT_SCAN_AND_CONNECT:
+   I: starting sample benchmark
+   I: Connected to F0:27:5B:37:0F:4B (random), number of connections 1
+   I: Connected to EE:37:AA:62:A2:FB (random), number of connections 2
+   I: Connected to D1:3D:B1:AA:84:27 (random), number of connections 3
+   I: Connected to CA:89:50:33:AB:31 (random), number of connections 4
+   I: Connected to C0:38:F8:47:10:17 (random), number of connections 5
+   I: Connected to E9:47:6B:FA:2F:DE (random), number of connections 6
+   I: Connected to D9:E5:51:E0:5E:24 (random), number of connections 7
+   I: Connected to FB:92:1D:8E:8C:D8 (random), number of connections 8
+   I: Connected to C7:E1:60:7A:F1:E0 (random), number of connections 9
+   I: Connected to E2:6D:21:28:C7:DB (random), number of connections 10
+   I: Connected to DF:02:31:C3:0B:C2 (random), number of connections 11
+   I: Connected to F0:F2:2A:C1:F7:72 (random), number of connections 12
+   I: Connected to DD:84:44:64:5D:FB (random), number of connections 13
+   I: Connected to F4:9C:8C:24:F9:44 (random), number of connections 14
+   I: Connected to EF:92:DC:88:3B:B3 (random), number of connections 15
+   I: Connected to C8:BA:1D:6F:95:2B (random), number of connections 16
+   I: 9 seconds to create 16 connections
+   I: Disconnecting connections...
+   I: ---------------------------------------------------------------------
+   I: ---------------------------------------------------------------------
+   I: CONCURRENT_SCAN_AND_CONNECT_FILTER_ACCEPT_LIST:
+   I: starting sample benchmark
+   I: Connected to DD:84:44:64:5D:FB (random), number of connections 1
+   I: Connected to C7:E1:60:7A:F1:E0 (random), number of connections 2
+   I: Connected to C7:9B:42:1B:48:F8 (random), number of connections 3
+   I: Connected to E9:47:6B:FA:2F:DE (random), number of connections 4
+   I: Connected to E2:12:BF:D3:FB:D5 (random), number of connections 5
+   I: Connected to FB:92:1D:8E:8C:D8 (random), number of connections 6
+   I: Connected to F0:F2:2A:C1:F7:72 (random), number of connections 7
+   I: Connected to CA:89:50:33:AB:31 (random), number of connections 8
+   I: Connected to F4:9C:8C:24:F9:44 (random), number of connections 9
+   I: Connected to E2:6D:21:28:C7:DB (random), number of connections 10
+   I: Connected to FF:AB:68:0C:34:FD (random), number of connections 11
+   I: Connected to EE:37:AA:62:A2:FB (random), number of connections 12
+   I: Connected to D1:3D:B1:AA:84:27 (random), number of connections 13
+   I: Connected to CF:2F:99:89:A3:4D (random), number of connections 14
+   I: Connected to EF:92:DC:88:3B:B3 (random), number of connections 15
+   I: Connected to D9:E5:51:E0:5E:24 (random), number of connections 16
+   I: 4 seconds to create 16 connections
+   I: Disconnecting connections...
+   I: ---------------------------------------------------------------------
+   I: ---------------------------------------------------------------------

samples/bluetooth/scanning_while_connecting/peripheral/CMakeLists.txt

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2020 Nordic Semiconductor ASA
+# Copyright (c) 2024 Nordic Semiconductor ASA
 #
 # SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 #

samples/bluetooth/scanning_while_connecting/peripheral/prj.conf

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2020 Nordic Semiconductor
+# Copyright (c) 2024 Nordic Semiconductor
 #
 # SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 #
@@ -10,7 +10,9 @@ CONFIG_BT=y
 CONFIG_BT_PERIPHERAL=y
 CONFIG_BT_CTLR_ADV_EXT=y
 CONFIG_BT_EXT_ADV=y
+CONFIG_BT_GAP_AUTO_UPDATE_CONN_PARAMS=n
 
-CONFIG_BT_EXT_ADV_MAX_ADV_SET=2
-CONFIG_BT_MAX_CONN=2
-CONFIG_BT_ID_MAX=2
+CONFIG_BT_EXT_ADV_MAX_ADV_SET=20
+CONFIG_BT_MAX_CONN=20
+CONFIG_BT_ID_MAX=20
+CONFIG_BT_BUF_ACL_RX_COUNT=21

samples/bluetooth/scanning_while_connecting/peripheral/src/main.c

@@ -74,15 +74,19 @@ static void start_connectable_advertiser(struct k_work *work)
 
 static int setup_advertiser(uint8_t id_adv)
 {
-	struct bt_le_adv_param adv_param =
-		BT_LE_ADV_PARAM_INIT(BT_LE_ADV_OPT_CONNECTABLE,
-				     BT_GAP_ADV_SLOW_INT_MIN,
-				     BT_GAP_ADV_SLOW_INT_MAX,
-				     NULL);
-
+	struct bt_le_adv_param adv_param = {
+		.id = BT_ID_DEFAULT,
+		.sid = 0,
+		.secondary_max_skip = 0,
+		.options = BT_LE_ADV_OPT_CONNECTABLE, // | BT_LE_ADV_OPT_EXT_ADV,
+		.interval_min = 800, /* Minimum Advertising Interval (N * 0.625 milliseconds) */
+		.interval_max = 800, /* Maximum Advertising Interval (N * 0.625 milliseconds) */
+		.peer = NULL,
+	};
+
 	size_t id_count = 0xFF;
 	int err;
-	
+
 	bt_id_get(NULL, &id_count);
 	if (id_adv == id_count) {
 		int id;
@@ -102,7 +106,7 @@ static int setup_advertiser(uint8_t id_adv)
 	printk("Using current id: %u\n", id_adv);
 	adv_param.id = id_adv;
 	advertisers[id_adv].id = id_adv;
-	
+
 	err = bt_le_ext_adv_create(&adv_param, NULL, &advertisers[id_adv].adv);
 	if (err) {
 		printk("Failed to create advertiser set (err %d)\n", err);
@@ -136,7 +140,7 @@ int main(void)
 	}
 
 	printk("Bluetooth initialized\n");
-	
+
 	printk("Starting %d advertisers\n", CONFIG_BT_EXT_ADV_MAX_ADV_SET);
 	for (uint8_t i = 0; i < CONFIG_BT_EXT_ADV_MAX_ADV_SET; i++)
 	{

samples/bluetooth/scanning_while_connecting/prj.conf

@@ -0,0 +1,23 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+CONFIG_NCS_SAMPLES_DEFAULTS=y
+
+CONFIG_BT=y
+CONFIG_BT_CENTRAL=y
+CONFIG_BT_FILTER_ACCEPT_LIST=y
+CONFIG_BT_SCAN_AND_INITIATE_IN_PARALLEL=y
+CONFIG_BT_CTLR_SDC_ALLOW_PARALLEL_SCANNING_AND_INITIATING=y
+
+# A ring buffer is used as a device address cache
+CONFIG_RING_BUFFER=y
+
+CONFIG_BT_CTLR_FAL_SIZE=255
+
+CONFIG_LOG=y
+
+CONFIG_BT_MAX_CONN=16
+CONFIG_BT_BUF_ACL_RX_COUNT=17

samples/bluetooth/scanning_while_connecting/sample.yaml

@@ -0,0 +1,16 @@
+sample:
+  description: Bluetooth Low Energy fast connection establishment sample
+  name: Bluetooth LE central scanning while connecting
+tests:
+  sample.bluetooth.scanning_while_connecting:
+    sysbuild: true
+    build_only: true
+    integration_platforms:
+      - nrf52840dk/nrf52840
+      - nrf5340dk/nrf5340/cpuapp
+      - nrf54l15dk/nrf54l15/cpuapp
+    platform_allow:
+      - nrf52840dk/nrf52840
+      - nrf5340dk/nrf5340/cpuapp
+      - nrf54l15dk/nrf54l15/cpuapp
+  tags: bluetooth ci_build sysbuild