Channel Sounding: Initiator with Ranging Requester

Overview

Application demonstrates the BLE requester role in an RAP (Ranging Profile) system and the initiator role for Channel Sounding. It can connect with a BLE responder application (Refer to ras_rrsp_reflector). And then gets channel sounding ranging procedure indication and data using GATT Ranging service control point write commands to the BLE Ranging Responser role.

Requirements

  1. Atmosic EVK <board | serial>

Note

  • Currently, only the ATM34/e series of Atmosic devices are supported.

  1. Button

    • Press Button2 to unpair the device.

    Note

    • The default pin for Button2 is P6.

    • Install the JP27 and JP25 jumpers to enable Button2.

  2. Antenna_switch: connect IO to switch antenna as channel sounding enable

  • Need to connect external antenna switch board for EVK

  • For the related pin setting, please refer to the overlay file.

  • If there is no overlay file, the function is disabled.

  • Refer to atmosic,antenna.yaml for below properties.

    • e.g. P5 as antenna switch (JP29 in EVK board).

      In the case, Button1 can not be used, since it is also used with P5.

    / {
 aliases {
  sw0 = &button1;
 };
};
&atm_antenna {
 ant-out5-pin = <5>;
 mdm-ant-rx-3to0 = <0x00002000>;
 mdm-ant-tx-3to0 = <0x00002000>;
 mdm-ant-idle =<0>;
 status = "okay";
};

    • e.g. P16 as antenna switch, and antenna0 with P16 high

    &atm_antenna {
 ant-out0-pin = <16>;
 mdm-ant-rx-3to0 = <0x00000001>;
 mdm-ant-tx-3to0 = <0x00000001>;
 mdm-ant-idle =<0x01>;
 status = "okay";
};

Configuration Options

Bluetooth Transmit Power Control

To enable Bluetooth transmit power control reporting functionality, add the following configuration option to your project configuration file (prj.conf):

CONFIG_BT_TRANSMIT_POWER_CONTROL=y

This option enables:

  • Transmit power control information reporting to the host

  • Support for transmit power reporting procedures in BLE connections

  • Power control status monitoring and feedback mechanisms

  • Enhanced visibility into power control operations for channel sounding

Note

This feature enables the reporting of power control information rather than direct power adjustment. It is useful for monitoring and debugging power control behavior in ranging applications.

RSSI Reading Support

To enable RSSI (Received Signal Strength Indicator) reading functionality, add the following configuration option to your project configuration file (prj.conf):

CONFIG_READ_RSSI=y

This option enables:

  • RSSI measurement and reporting capabilities

  • Signal strength monitoring for BLE connections

Note

RSSI readings provide valuable signal strength information that can be used to improve connection quality assessment.

BLE PHY Mode Selection

To enable BLE PHY mode selection and automatic PHY updates, add the following configuration options to your project configuration file (prj.conf):

CONFIG_ATM_BT_PHY_UPDATE=y
CONFIG_ATM_BT_PHY=0

These options enable:

  • Flexible PHY mode selection (0=1M, 1=2M, 2=Coded)

  • Automatic PHY update to the configured mode if a different PHY is detected during connection

  • Retry mechanism for PHY update failures

Configuration Details

CONFIG_ATM_BT_PHY_UPDATE: Enable/disable automatic PHY updates

  • When enabled, the system will automatically attempt to update the PHY to the configured mode if a different PHY is detected

  • Up to 3 retry attempts are made if PHY update fails

CONFIG_ATM_BT_PHY: Select the preferred PHY mode

  • 0: 1M PHY (default) - Enhanced range and signal penetration for long-distance testing

  • 1: 2M PHY - Higher data rate for improved throughput

  • 2: Coded PHY - Extended range with lower data rate

Example configurations:

# For long-distance Channel Sounding with 1M PHY
CONFIG_ATM_BT_PHY_UPDATE=y
CONFIG_ATM_BT_PHY=0

# For high-throughput scenarios with 2M PHY
CONFIG_ATM_BT_PHY_UPDATE=y
CONFIG_ATM_BT_PHY=1

# For extended range with Coded PHY
CONFIG_ATM_BT_PHY_UPDATE=y
CONFIG_ATM_BT_PHY=2

Note

This feature is specifically designed for Channel Sounding applications where PHY mode selection is critical for optimal performance. The automatic PHY management ensures consistent PHY usage throughout the connection lifecycle.

Important

Reflector Configuration Requirement: When testing with a reflector device (e.g., ras_rrsp_reflector), the reflector must disable auto phy CONFIG_BT_AUTO_PHY_UPDATE=n. If not, PHY mismatches may occur during the connection, potentially affecting Channel Sounding performance and range measurements.

Building and Running

This application is built from openair/applications/ras_rreq_initiator.

Build with UART0 as console and shell command:

west build -p always -b <BOARD> openair/applications/ras_rreq_initiator --sysbuild -T applications.ras_rreq_initiator.atm

Build with UART1 as console and shell command:

west build -p always -b <BOARD> openair/applications/ras_rreq_initiator --sysbuild -T applications.ras_rreq_initiator.atm.uart1

Flash command:

west flash --skip-rebuild --device <DEVICE_ID> --jlink --fast_load [--erase_all]